HomeMy WebLinkAbout24IWC11-375 Maple Ave REV Stormwater Management Report 1-13-25STORMWATER
MANAGEMENT PLAN
Proposed Trailer Storage Facility
375 Maple Avenue & Route 163 Montville, Connecticut
Prepared For:
349 Maple Ave, LLC & Rand-Whitney Realty, LLC
December 16, 2024
(Revised January 13, 2025)
Prepared By: CLA Engineers, Inc.
Consulting Engineers 317 Main Street Norwich, CT 06360
Ph: 860-886-1966 F: 860-886-9165 www.claengineers.com
Kyle Haubert, P.E.
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility 375 Maple Ave & Route 163
CLA Engineers, Inc.
Civil · Structural · Survey
STORMWATER MANAGEMENT PLAN Proposed Trailer Storage 375 Maple Avenue & Route 163
Montville, Connecticut Prepared for Rand-Whitney Containerboard TABLE OF CONTENTS
1.0 Introduction ........................................................................................................................ 1
2.0 Standard 1 – Runoff Volume and Pollutant Reduction ................................................. 7
3.0 Standard 2 – Stormwater Runoff Quantity Control .................................................... 13
4.0 Standard 3 – Construction of Soil Erosion and Sediment Control ............................. 14
5.0 Standard 4 - Post-Construction Operation and Maintenance ..................................... 16
LIST OF FIGURES
Figure 1: Location Map (USGS)
Figure 2: 2019 Aerial Map
Figure 3: Existing Conditions Watershed Plan
Figure 4: Proposed Conditions Watershed Plan
APPENDICES
Appendix A: NRCS Soil Report
Appendix B: Hydrograph Reports - 2, 10, 25, 50, and 100-Year Frequencies
Appendix C: Rainfall Data
Appendix D: StreamStats Report
Appendix E: Design Plan Set (Separate Document)
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 1
1.0 Introduction
The project is to provide additional trailer storage space for Rand-Whitney Containerboard’s
transportation operations, which are currently at maximum capacity. The project proposes
construction of a paved storage area and access road for the storage of box trailers on two parcels
of land owned by the parent company. The two parcels are located at 375 Maple Avenue (Parcel
ID P0128100) and the adjoining parcel, Route 163 (Parcel ID R0128600) in Montville, CT. The
parcels are recorded as owned by two subsidiary companies namely, 349 Maple Ave LLC and
Rand-Whitney Realty LLC respectively.
The storage area will be accessed primarily by an internal paved driveway that will connect to
Robertson Road, thus minimizing traffic impact to Maple Avenue. The driveway will be
constructed on the parcel recorded as ‘Route 163’. A secondary access from Maple Avenue is
proposed to be constructed however, this access is intended for emergency access only and will be
chained to prevent general access. The location of both parcels is shown on Figure 1, and in relation
to the 2019 Connecticut orthoimagery as Figure 2. A location map is also included on the Site
Development Plans.
As part of this project, the Town of Montville’s existing 30” stormwater pipe, that currently
discharges onto 375 Maple Avenue, will be extended and a new drainage easement in favor of the
Town of Montville will be established.
This report was prepared to address the Soil Erosion and Sediment Control and Stormwater
Management requirements stipulated in the Town of Montville’s Planning and Zoning
Regulations. The Soil Erosion and Sediment Control Plan has been developed in accordance with
the 2023 Connecticut Guidelines for Soil Erosion and Sediment Control. The stormwater
management and quality has been designed in accordance with the 2024 Connecticut Stormwater
Quality Manual. A full-size Design Plan Set is included separately as Appendix E.
Existing Conditions
Both parcels are located in an industrial zone which straddles the Oxoboxo Brook. Parcel Route
163 is approximately 34.6 acres in area and is mostly comprised of Rockland Pond; a manmade
pond formed by the damming of Oxoboxo Brook in 1900. The Rockland Pond Dam (CT00242) is
owned and maintained by Rand-Whitney Containerboard. The only developed portion of Parcel
Route 163 is located at its northeast corner which is used as a trailer storage area.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 2
375 Maple Avenue is approximately 2.94-acres comprised mostly of undeveloped land located on
the southwest side of Oxoboxo Brook. A residential house was originally present on the lot but
has recently been raised. The land is currently cleared and ready for development. Access is from
Maple Avenue only.
Soils
A custom soil resource report for the property was mapped using NRCS Web Soil Survey website and are listed in the table below.
Soil in the area of development mainly consist of Merrimac fine sandy loam (Hydrological Group
A) and Urban Fill (Hydrological Group D). Further details of the soils located on site are presented
in Appendix A
Wetland hydrology
Two wetland areas have been identified and delineated on the project site. The first is the 13-acre
watercourse and pond area comprised of Oxoboxo Brook and Rockland Pond. This wetland is a
large but somewhat degraded open water ecosystem. Oxoboxo Brook flows eventually into the
Thames River, a major watercourse connected with the Long Island Sound (Atlantic Ocean). No
work is proposed within this wetland, but a portion of the development area coincides with the
wetland’s 50-foot upland review area.
The second wetland area on the project site is a small (<1ac) man-made channelized wetland in
the northeast corner of 375 Maple Avenue. The channel formed as a result of the discharge of
stormwater over time by the Town of Montville’s 30” storm pipe (identified on plans). This
wetland appears to have existed for fewer than 50 years based on available online mapping from
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 3
CTECO (although the pipe itself appears to be older than 50 years) and is not associated with any
watercourse. CLA believes it to have a small impact on groundwater recharge. The wetlands
principal functions and the impacts to this and downstream wetlands are evaluated and detailed in
the Wetland Letter Report.
Existing Watershed Hydrology
An existing conditions watershed map and stormwater flow paths are included as Figure 3. The
site is located in CTDEEP Local Stormwater Basin 3004-00 (Oxoboxo Brook) and drains in a
northeasterly direction. Run-off from the site is directed to the Oxoboxo Brook both upstream and
downstream of the dam. Run-off from the northwest portion of the site drains to Rockland Pond,
which is upstream of the dam (Ex Watershed 1). The remaining southeast portion of the site drains
to the downstream side of the dam before passing beneath Robertson Road and through the Rand
Whitney facility (Ex Watershed 2).
An existing municipal storm drain
system originating from Sharp Hill
Road enters the property and daylights
approximately 200 feet from the
southwest property line. The system
comprises a 30” corrugated metal pipe
that conveys stormwater from the
roadway collection system located on
Sharp Hill Road and Carol Drive. The
drainage system is also used to collect
overland flow from upgradient areas.
Over the course of time, the discharge has eroded the surface soils to create a fairly uniform
channel that flows east and into the Oxoboxo Brook. The periodic discharge has created a man-
made channelized wetland less than 1-acre in area, running directly over the town’s sanitary sewer
line and, according to the WPCA, causes unwanted infiltration issues. The town has no known
rights to drain onto the property and in its current location, will interfere with the proposed
development. The project proposes to extend the pipe through the property and relocate the point
of discharge to avoid conflict with the proposed improvements.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 4
Existing Watershed 1 is located at the
northwest portion of the property. It
comprises cleared woodland and some
rock outcrops and remnants of the
foundation from the raised residential
house. Grades are moderate to slight.
Run-off from this watershed is directed
overland in a northerly direction where
it eventually reaches Rockland Pond.
This is considered Analysis Point 1.
Analysis Point 1 – Rockland Pond
Existing Watershed 2 comprises the
remainder of the southeast portion of
the property. It comprises cleared
woodland and brush with moderate to
slight slopes. Run-off from this
watershed flows northeast and is
intercepted by the man-made channel
associated with the town’s storm drain
discharge. It then follows the channel
and eventually discharges to the
Oxoboxo Brook immediately upstream
of the Robertson Road culvert. This is
considered Analysis Point 2.
Analysis Point 2 – Oxoboxo Brook
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 5
Proposed Conditions
A proposed conditions watershed map and stormwater flow paths are included as Figure 4. The
proposed development includes construction of a paved laydown area sufficient to accommodate
61 storage spaces for trailers and paved driveways that access Maple Avenue and Robertson Road.
The approximate total area of disturbance is 3.9 acres and impervious area to be constructed is
approximately 2.14 acres. The proposed site improvements are depicted on the Site Improvement
Plans.
As previously mentioned, the Town of Montville’s existing 30” storm drain will be extended
through the limits of the site with the point of discharge relocated to the northeast, beyond the
limits of paving.
Proposed Watershed Hydrology
The proposed site grading will mimic existing drainage patterns and run-off from the site will
continue to be directed to the Oxoboxo Brook both upstream and downstream of the dam. Run-off
from the northwest portion of the site will be directed to drain towards Rockland Pond, which is
upstream of the dam (Pr Watershed 1) and the southeast portion of the site will continue to drain
to Oxoboxo Brook on the downstream side of the dam (Pr Watershed 2).
Pr-Watershed 1
Proposed Watershed 1 comprises the developed area that produces run-off directed towards and
discharges to Rockland Pond (Upstream of Rockland Pond Dam). The watershed comprises the
newly developed area (Pr Watershed 1a) and the remaining undeveloped area (Pr Watershed 1b).
Run-off from the developed portion of the watershed will be directed northeast and intercepted by
a perimeter grass-lined swale where it will be conveyed and discharged to Water Quality Basin 1.
Stormwater that leaves Basin 1 will discharge over a rip-rap lined level spreader before entering
Rockland Pond (Analysis Point 1)
Pr-Watershed 2
Proposed Watershed 2 comprises the remaining developed area that will ultimately discharge to
the Oxoboxo Brook downstream of the Rockland Pond Dam. A portion of this watershed will be
directed towards Water Quality Basin 2 (Pr Watershed 2a) and the remaining developed area
comprising the Robertson Road driveway (Pr Watershed 2b) will discharge directly to Oxoboxo
Brook.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 6
Hydrological Analysis:
The site stormwater hydrological analysis was performed for the 2-year, 10-year, 25-year, 50-year
and 100-year frequency storms using the USDA/NRCS TR-55 method to determine the peak flow
rates from the existing and post development conditions. As recommended by the CT Stormwater
Quality Manual, a Type D storm distribution was used. Precipitation data, rainfall intensities, and
distribution were acquired from NOAA Atlas 14, Volume 10, Version 3 for the site, and is included
in Appendix B. Rainfall data obtained from NOAA Atlas 14 is included in Appendix C.
The soils onsite in the area of development fall into the hydrologic soil groups A and D. A copy
of the soil mapping is included in Appendix A. The runoff curve numbers for the site are based on
the ground cover and hydrologic soil group and are included in Table 1.
Table 1 – Curve Numbers
Runoff curve numbers for the existing and post development conditions were compiled from Table
2-2 of the USDA/NRCS TR-55 manual. The following curve numbers were used for the
calculations. Weighted curve number calculations are included in the hydrograph reports.
Existing Conditions CN
Good Condition Woods (HSG A) 30 Good Condition Woods (HSG D) 77 Good Condition Open Space (HSG A) 39 Pavement 98
Post Development CN Good Condition Woods (HSG A) 30 Good Condition Woods (HSG D) 77 Good Open Space (HSG A) 39
Pavement 98
Stormwater Management Standards and Performance Criteria
The design of the stormwater management is required to meet and comply with the standards and
performance criteria using non-structural Low Impact Development (LID) site planning and design
techniques and structural stormwater Best Management Practices (BMPs), in addition to
operational source controls and pollution prevention. The following standards are set out in
Chapter 4 of the 2024 Connecticut Stormwater Quality Manual (SQM) and are intended to be
consistent with the post-construction stormwater management requirements of the CTDEEP
stormwater general permits, as well as local requirements within municipal planning, zoning, and
stormwater ordinances and regulations.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 7
2.0 Standard 1 – Runoff Volume and Pollutant Reduction
The purpose of this Standard is to preserve pre-development hydrology and pollutant loads to
protect water quality and maintain groundwater recharge. For the purposes of this standard, this
project is considered a new development, and therefore the Required Retention Volume (RRV) is
equal to 100% of the site’s Water Quality Volume (WQV). To meet this standard, a combination
of pre-treatment devices and water quality basins have been designed for the site in accordance
with the 2024 Connecticut Stormwater Quality Manual to treat the proposed stormwater runoff.
Proposed Watershed 1 (Analysis Point 1)
Stormwater runoff from post development Watershed 1 originates from the combined discharge
associated with Pr Watershed 1a and Pr Watershed 1b. Runoff from Pr Watershed 1b comprises
open space with landscaping and requires no treatment.
Run-off from new pavement associated with Pr Watershed 1a will sheet flow to vegetated swales
that will convey stormwater to two sediment forebays in advance of entering Stormwater Basin 1.
Although the vegetated swales will provide some level of pre-treatment, no credit for the
stormwater’s residency time in the swales has been taken and Pre-treatment will be provided by
the two sediment forebays.
Two test pits (TP 1 & TP 9) were performed in the vicinity of Basin 1. TP 1 exhibited the most
restrictive conditions where groundwater was observed at elevation 230.3 and mottling at elevation
231. No ledge was observed. To provide sufficient volume to address run-off volume and pollutant
reduction, the bottom elevation of Basin 1 was set at elevation 231.0. The basin bottom elevation
will therefore be at or close to the seasonally high-water level (SHWL).
The soils in the vicinity of Basin 1 are Hydrological Group A which are conducive for infiltration.
While the recommended vertical separation between the basin bottom and the SHWL will not be
achieved, infiltration will still occur through the bottom and sides of the basin due to hydraulic
pressure head differences. The volume of water required to be treated (WQV) and the available
volume provided by the basin is calculated as follows:
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 8
Pr Watershed 1a (Basin 1)
Water Quality Volume (WQV)
Sizing in Accordance with Chapter 4 of the DEEP 2024 Storm Water Quality Manual
Water Quality Volume (WQV) = (P)(R)(A) / 12
P = 1.3"
R = 0.05 + 0.009(I)
I = percent of impervious cover
A = watershed area
Total Watershed Area (Ac.) : 1.92
Watershed Impervious Area (Ac.) : 1.11
I = 0.58
R = 0.57
Required WQV = 0.12 Ac.-Ft
= 5154 CF
Volume Provided = 24,172 CF
Proposed Water Quality Basin 1 contains 24,172 CF of storage below the primary outlet elevation.
No flow over the primary outlet is predicted to leave the basin during a 25-year storm event and
only 0.35 cfs is expected to leave basin during the 100-year event. The excess volume provided is
required to address Standard 2 – Stormwater Run-off Quantity Control and will be discussed in
the next section.
The dimensions and volume of the sediment forebays have been designed in accordance with
Chapter 13 of the DEEP 2024 Storm Water Quality Manual as follows:
Based on the combination of the vegetated swales and the oversized sediment forebays and
treatment basins, CLA believes that the stormwater system shown on the project plans is consistent with the CTDEEP 2024 Manual.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 9
Sediment Forebay 1a
Water Quality Volume (WQV)
Sizing in Accordance with Chapter 4 of the DEEP 2024 Storm Water Quality Manual
Water Quality Volume (WQV) = (P)(R)(A) / 12
P = 1.3"
R = 0.05 + 0.009(I)
I = percent of impervious cover
A = watershed area
Total Watershed Area (Ac.) : 0.91
Watershed Impervious Area (Ac.) : 0.73
I = 80.13%
R = 0.77
Required WQV = 0.08 Ac.-Ft
3,312 CF
Bottom Surface Area = 0.066 * %WQV
Recommended % of WQV to be Treated 25%
Minimum Bottom Surface Area = 55 sf
Bottom Surface Area Provided = 185 sf
Min. Volume = 25% of the WQV below the outlet invert
25% of the WQV = 828 cf
Volume Provided = 1,020 cf
Sediment Forebay 1b
Water Quality Volume (WQV)
Sizing in Accordance with Chapter 4 of the DEEP 2024 Storm Water Quality Manual
Water Quality Volume (WQV) = (P)(R)(A) / 12
P = 1.3"
R = 0.05 + 0.009(I)
I = percent of impervious cover
A = watershed area
Total Watershed Area (Ac.) : 0.55
Watershed Impervious Area (Ac.) : 0.38
I = 69.06%
R = 0.67
Required WQV = 0.04 Ac.-Ft
1,737 CF
Bottom Surface Area = 0.066 * %WQV
Recommended % of WQV to be Treated 25%
Minimum Bottom Surface Area = 29 sf
Bottom Surface Area Provided = 405 sf
Min. Volume = 25% of the WQV below the outlet invert
25% of the WQV = 434 cf
Volume Provided = 1,897 cf
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 10
Proposed Watershed 2 (Analysis Point 2)
Stormwater runoff from post development Watershed 2 comprises the combined discharge
associated with Pr Watershed 2a and Pr Watershed 2b.
Stormwater runoff from Proposed Watershed 2a will sheet flow to a vegetated swale that will
convey stormwater to a sediment forebay in advance of entering Stormwater Basin 2. Similarly,
no credit for the stormwater’s residency time in the swales has been taken and pre-treatment will
be provided by the sediment forebay.
The volume of water required to be treated (WQV) and the available volume provided by the basin
is calculated as follows:
Pr Watershed 2a (Basin #2)
Water Quality Volume (WQV)
Sizing in Accordance with Chapter 4 of the DEEP 2024 Storm Water Quality Manual
Water Quality Volume (WQV) = (P)(R)(A) / 12
P = 1.3"
R = 0.05 + 0.009(I)
I = percent of impervious cover
A = watershed area
Total Watershed Area (Ac.) : 1.11
Watershed Impervious Area (Ac.) : 0.79
I = 71.2%
R = 0.69
Required WQV = 0.08 Ac.-Ft
3,625 CF
Volume Provided = 9,515 cf
Proposed Water Quality Basin 2 contains 9,515 CF of storage below the primary outlet elevation.
Similarly, no flow over the primary outlet is predicted to leave the basin during a 2-year storm
event and only 0.1 cfs is expected to leave basin during 10-year event. The excess volume provided
is required to address Standard 2 – Stormwater Run-off Quantity Control and will be discussed in
the next section.
Pre-treatment for stormwater flow into the basin is achieved by routing flow through an in-line
sediment forebay. The dimensions and volume of the sediment forebay have been designed in
accordance with Chapter 13 of the DEEP 2024 Storm Water Quality Manual as follows:
CLA Engineers, Inc.
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Proposed Trailer Storage Facility
375 Maple Ave & Route 163 11
Sediment Forebay 2
Water Quality Volume (WQV)
Sizing in Accordance with Chapter 4 of the DEEP 2024 Storm Water Quality Manual
Water Quality Volume (WQV) = (P)(R)(A) / 12
P = 1.3"
R = 0.05 + 0.009(I)
I = percent of impervious cover
A = watershed area
Total Watershed Area (Ac.) : 1.04
Watershed Impervious Area (Ac.) : 0.79
I = 76.18%
R = 0.74
Required WQV = 0.08 Ac.-Ft
3,608 CF
Bottom Surface Area = 0.066 * %WQV
Recommended % of WQV to be Treated 25%
Minimum Bottom Surface Area = 60 sf
Bottom Surface Area Provided = 240 sf
Min. Volume = 25% of the WQV below the outlet invert
25% of the WQV = 902 cf
Volume Provided = 1,709 cf
Runoff from Pr Watershed 2b comprises the impervious area associated with the driveway between
the trailer storage area and Robertson Road. Runoff from this area will be directed to a Qualifying
Pervious Area (QPA) adjacent to the driveway. The SQM explains that certain areas of impervious
area can be directed to natural or landscaped vegetated areas that are of sufficient size and with
adequately permeable soils to disperse and retain runoff without causing erosion or negative
impacts to adjacent downgradient properties.
Certain criteria should be met in order for the QPA to qualify for credit. In general, the following
criteria of the proposed QPA will be met:
• The proposed QPA is located outside of the regulated wetland
• The QPA is remote from any buildings
• The portion of the QPA disturbed during construction shall receive 6 inches of topsoil and
seeded with New England Roadside Matrix Mix to promote healthy vegetative cover. The
remainder of the undisturbed QPA currently consists of dense vegetation covering more
than 90% of the area.
• To limit unnecessary disturbance to the existing vegetation downgradient of the QPA,
grading has been set to 15%. This meets the maximum grade criteria for undisturbed
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forested areas. Although this area will initially be loamed and seeded to promote
vegetative growth, this area will not be maintained as lawn and is expected to quickly
repopulate with larger vegetation that will promote sheet flow residency times.
Other criteria specific to driveways include:
• the maximum contributing flow path from the driveway to the QPA will be 30-feet (width
of the driveway).
• The length of the QPA will be equal to the length of the driveway and the width of the
QPA (min. 64-feet) will be more than twice the width of the driveway.
• Salt tolerant New England Roadside Matrix Upland Seed Mix will be placed immediately
next to the roadside.
Additionally, to provide pre-treatment to the run-off, a 2-feet wide, 3-feet deep stone filled choker
trench will be installed adjacent to the driveway. This will provide initial pre-treatment through
nominal detention (40% stone voids), sediment retention and prevent road edge deterioration.
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Proposed Trailer Storage Facility
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3.0 Standard 2 – Stormwater Runoff Quantity Control
The purpose of this standard is to ensure that pre-development peak flow rates are not exceeded
and manage the volume and timing of runoff to prevent downstream flooding, channel erosion,
and other adverse impacts, and safely convey flows into, through and from structural stormwater
BMPs.
To mitigate peak stormwater runoff rates due to the proposed increased impervious area onsite,
stormwater will be routed through two water quality basins that have been sized to detain sufficient
volumes of water to mitigate post-development peak flows. A summary of the existing condition
and post development peak flow rates from the site are included in Table 2.
Table 2 – Peak Flow Rates
Analysis Point 1 Peak Flow Rate (CFS)
per Storm Event
2-Year 10-Year 25-Year 50-Year 100-Year
Existing Conditions 0.00 0.02 0.10 0.25 0.55
Proposed Conditions 0.00 0.00 0.04 0.17 0.35
Difference 0.00 -0.02 -0.06 -0.08 -0.20
Analysis Point 2 Peak Flow Rate (CFS)
per Storm Event
2-Year 10-Year 25-Year 50-Year 100-Year
Existing Conditions 0.01 0.24 0.77 1.40 2.20
Proposed Conditions 0.52 1.50 2.26 2.84 3.48
Difference 0.51 1.26 1.49 1.44 1.28
Site Wide Peak Flow Rate (CFS)
per Storm Event
2-Year 10-Year 25-Year 50-Year 100-Year
Existing Conditions 0.01 0.24 0.86 1.64 2.72
Proposed Conditions 0.52 1.52 2.29 2.94 3.65
Difference 0.51 1.28 1.43 1.30 0.93
For Analysis Point 1, the proposed design maintains or reduces the peak stormwater flow rates in
comparison to the existing conditions across all storm events.
For Analysis Point 2, small increases in run-off will be realized. This is attributed to the Qualifying
Pervious Area not able to sufficiently detain run-off from the proposed driveway.
CLA Engineers, Inc.
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Proposed Trailer Storage Facility
375 Maple Ave & Route 163 14
A USGS StreamStats report was generated for the watershed area contributing to the Oxoboxo
Brook immediately upstream of Robertson Road (See Appendix D). The report approximates the
watershed area to be 9.66 square miles with the following peak flows using the Area-Averaged
Method.
2-Yr (CFS) 10-Yr (CFS) 25-Yr (CFS) 50-Yr (CFS 100-Yr (CFS)
326 608 805 978 1170
Given the significant watershed area and existing peak flows, the increases in proposed peak flows
leaving the site are negligible and we believe no negative downstream impacts will occur.
Hydrographs detailing the calculations are included in Appendix B.
4.0 Standard 3 – Construction of Soil Erosion and Sediment Control
The 2023 CT Guidelines for Soil Erosion & Sedimentation Control applies to the construction
phase of the project. A detailed erosion and sediment control plan has been provided in the site
development plans. Due to the existing topography and the restrictive nature of the site, the
proposed stormwater basins have been designed to function as temporary sedimentation traps
during stabilization, and then to be converted to provide permanent water quality treatment for the
life of the facility. While the guidelines do not recommend locating sediment traps in the proposed
locations of permanent, post-construction stormwater BMPs, they recognize in some cases, this is
unavoidable and require the sediment traps to be modified after their function is complete, to
prepare it for long-term use. In this case, the bottom elevations of the sediment traps are designed
to be at least 1-foot above the bottom floor elevation of the permanent stormwater basins, to avoid
fine soil particles sealing the underlying soils. Removal of accumulated sediment and, if necessary,
restoration of the pre-construction infiltration capacity of the underlying soils will be performed.
Trap Capacity
The temporary sediment trap shall have an initial storage volume of 134 cubic yards per acre of
drainage area. Half of this volume shall be in the form of wet storage to provide a stable settling
medium. The remaining storage volume shall be in the form of a drawdown (dry storage) which
will provide extended settling time during less frequent, larger storm events.
The dimensions and volume of the sediment traps have been designed in accordance with Chapter
5 of the Connecticut Guidelines for Soil Erosion and Sediment Control as follows:
CLA Engineers, Inc.
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Proposed Trailer Storage Facility
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Sediment Trap 1 Sediment Trap 2
Area of Disturbance (Acres) 1.51 1.62
SSV Required per Acre of
Disturbance 134 134
SSV Required = (CY) 202 217
Total Storage Provided = (CY) 675 308
Dry Storage Volume Required CY = 101 109
Dry Storage Volume Provided CY = 370 172
Wet Storage Volume Required CY = 101 109
Wet Storage Volume Provided CY = 305 136
General Slope Protection Erosion Control Matting shall be installed on all side slopes of 3H:1V in accordance with the
Erosion Control Matting Detail. Matting must be listed on the latest CTDOT Qualified Products List under Class 1 Slope Protection Type D. Erosion Control Matting (Swales)
Within the proposed grassed lined swales, a temporary (bio-degradable) lining will be required to convey runoff until grass (turf) can be established. Class 2, Flexible Channel Liner Protection shall be used for temporary linings. The specific Type shall be based on the proposed permissible shear stress calculated as follows for the 10-year storm event.
According to Section 7.6.7 of the CTDOT Drainage Manual, roadside drainage channels are designed to carry the 10-year design flow, and a 2-year return period is used for the design of temporary linings. The following hydraulic characteristics for each swale labeled on the Proposed Watershed Plan were calculated using Hydraflow Express Extension for Autodesk and the Mannings’s Equation for a trapezoidal channel:
CLA Engineers, Inc.
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Proposed Trailer Storage Facility
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Flow Characteristics for 2-Yr Event Swale
1a
Swale
1b Swale 1c Swale 2
Runoff Coefficient 0.9 0.9 0.9 0.9
5 Min. Intensity (in/hr) 4.87 4.87 4.87 4.87
Contributing Drainage Area (Ac) 0.18 0.73 0.88 0.58
Volume (Q) 0.8 3.2 3.9 2.5
Bottom Width (ft) 2 2 2 2
Slope (%) 3.7 0.5 1.8 1.7
Side slopes (Z:1) 3 3 3 3
Manning's n (HEC-15) 0.05 0.05 0.05 0.05
Depth of Flow (ft) 0.2 0.7 0.5 0.4
Velocity (Ft./Sec) 1.5 1.2 2.0 1.7
Max Shear Stress (lb/ft2) 0.5 0.2 0.6 0.5
Erosion control matting is evaluated by the CTDOT for use in eight Types (A-H), grouped into
two Classes. Types E through H are included in Class 2 and are designated as Flexible Channel Liner Protection. This classification is based upon the permissible shear stress of the material. The purpose of Class 2 matting is to protect the geometry of a channel from loss of soil, and to promote the establishment of a warm-season, perennial vegetative cover. Class 2 Types are designated
according to the shear stress limits shown in Table 7-5. The shear stress ranges are based on values published in HEC-15.
Given the maximum shear stress values calculated above, Type F matting shall be used.
5.0 Standard 4 - Post-Construction Operation and Maintenance
The purpose of this standard is to ensure that long-term maintenance of the structural stormwater management systems is performed so they continue to function as designed and to implement operational source control and pollution prevention measures.
Town of Montville 30” Drainage Pipe Capacity
As mentioned earlier in the report, the town of Montville’s existing 30” drainage pipe is required
to be replaced so that its vertical alignment and discharge location does not interfere with the
proposed development. The pipe will be replaced on its existing horizontal alignment and the
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 17
discharge point relocated north and east, beyond the area of development and closer to the
Oxoboxo Brook.
Proposed site grading requires the slope of the pipe to be lowered through the site. The pipe
provides conveyance for run-off from the Sharp Hill Road drainage system. To ensure the new
pipe has sufficient volume, a Manning’s pipe flow calculation was performed of the down-stream
most pipe of the Sharp Hill Road drainage system, prior to crossing Maple Avenue and entering
the 30” pipe.
Maximum volume Q (cfs) = A *1.486/n * R2/3 * S1/2 = 71 c.f.s
Where: Pipe Dia. = 24”
Slope = 8.6% (Grade at bottom of Sharp Hill Road)
n = 0.013 (Concrete)
This represents the theoretical maximum flow rate for a straight length of pipe with no energy loss
from in-line structures. In practice, the volume is likely to be less.
The proposed drainage pipe to be replaced through the development will be constructed in three
sections connected by two manholes. The first section of pipe will be a 30” HDPE installed at
2.9%.
Maximum volume of the 30” pipe Q (cfs) = 81 c.f.s (in excess of 71 c.f.s.)
Where: Pipe Dia. = 30”
Slope = 2.9%
n = 0.012 (HDPE)
To reduce velocity at the point of discharge, the last two sections of pipe will be increased to 36”
in diameter and installed at less grade. Due to hydraulic head pressure from the upstream section,
the final section of pipe will be ignored.
Maximum volume of the 36” pipe Q (cfs) = 101 c.f.s (in excess 71 c.f.s.)
Where: Pipe Dia. = 36”
Slope = 2.9%
n = 0.012 (HDPE)
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 18
Using Manning’s equation to calculate flow velocity V:
Maximum Flow Velocity V = (1.49/n)Rh2/3S1/2 = 14.6 feet/sec*
*In practice, velocity is expected to be lower.
Section 11.13 of the CTDOT Drainage Manual provides guidance on rip-rap stone size based on
discharge velocity and apron size. Given there will be minimal tail conditions, a Type A rip-rap
apron will be proposed.
The following dimensions were
Q= 71 cfs
Sp 2.5 feet
La= 40.1 feet
W1= 7.5 feet
W2= 35.5 feet
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 19
Provisions for the post-construction operation and maintenance of the permanent stormwater
management and pollution prevention devices are outlined on the plans and are as follows:
1. Pollution Prevention Team:
The Owner shall be responsible for carrying out the provisions of the plan.
2. Sweeping:
Parking lots, sidewalks, and other impervious surfaces shall be swept clean of
sand and litter and any other pollutants at least twice per year
a. Between November 15th and December 15th (after leaf fall)
b. During April (after snow melt)
3. Outside Storage:
Accessories or equipment stored outside shall be covered or maintained to
minimize the possibility of these materials or their residue passing to stormwater.
4. Washing:
No washing of vehicles, accessories, equipment, or appliances onsite.
5. Maintenance and Inspection of Stormwater Infrastructure:
a. Monthly inspection of stormwater structures and outfalls.
b. Clean sediment and debris from structures at least once per year during April.
c. Comply with the hydrodynamic separator operations and maintenance
requirements in accordance with the Operations and Maintenance Manual
provided by the Manufacturer.
d. Comply with the rain garden maintenance schedule.
6. Spills or Accidental Discharges:
a. Comply with State and Federal regulations to contain and clean up any spill or
discharge and dispose of materials at an approved facility.
b. Contact Connecticut DEEP oil and chemical spill response division 860-424-
3338.
c. The following steps should be performed as soon as possible
- Stop the source of the spill
- Contain the spill
- Cover the spill with absorbent material such as kitty litter, saw dust, or oil
absorbent pads. Do not use straw.
- Dispose of absorber in accordance with Local and State regulations.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 20
The following is a general operations and maintenance schedule for the stormwater infrastructure
and project site.
MAINTENANCE SCHEDULE FOR STORMWATER BASINS
Activity Schedule
Prior to new spring growth reaching a height of 2” (e.g., shortly after forsythia or redbud blooms), trim any material standing from the previous year close to the ground (approximately 2”).
Second growing season
This will allow the soil to warm more quickly, which will
stimulate the emergence and growth of native seedlings and reduce the likelihood of the meadow being invaded by shrubs.
Problem weeds should be hand pulled or spot sprayed with an approved herbicide, such as Rodeo® or Garlon® 3A.
If you did not plant vines or spiny plants as part of your mix, be vigilant about controlling them. These are more easily pulled when they are young rather than after they have had two to three months of growth. Examples include bindweed, blackberry, multiflora rose, mile-a-minute and Japanese hops. Be equally vigilant about controlling other invasive species, such as autumn olive and Japanese knotweed.
Special Circumstances
If you notice a heavy infestation of ragweed or foxtail in the
second growing season, trim the meadow to a height of 8”. Trimming should cease by mid-September.
For the basin and side slopes, inspect for invasive vegetation. Monthly
Grassy weeds or persistent perennials can re-establish in these soils. Monitor and control weeds by hand pulling or spot spraying. Inspect for damage, undercut, or eroded area Semi-Annually
Inspect Sediment Forebay and monitor for sediment accumulation. Remove any trash and organic debris (leaves) in
spring & fall. Remove sediment from the sediment forebay or other pretreatment area when it accumulates to a depth of more than 12 inches or 50% of the design depth. Clean outlet of sediment forebay or other pretreatment measures when drawdown time exceeds 36 hours after the end of a storm event. Remove sediment from the infiltration basin surface when the sediment accumulation exceeds 2 inches or when drawdown
time exceeds 48 hours after the end of a storm event, indicating that the system is clogged.
Weed as necessary. Mow grass within infiltration basin to a height of 3 to 6 inches. Maintain a healthy, vigorous stand of grass cover; re-seed as necessary. Clean and remove debris & sediment from inlet and outlet structures.
CLA Engineers, Inc.
Civil · Structural · Survey
December 16, 2024 (Revised January 13, 2025)
Stormwater Management Report
Proposed Trailer Storage Facility
375 Maple Ave & Route 163 21
Mow side slopes. Close mowing throughout the regular growing
season or extensive chemical use is not conducive to water quality improvement and wildlife habitat. Spring mowed vegetation can typically remain within basins providing cover for new emerging vegetation.
Repair undercut or eroded areas. As needed maintenance
Maintenance Schedule for Trailer Storage Areas
Activity Schedule
Sweep parking lots & impervious areas Between November 15th and December 15th (after leaf fall)
During April (after snow melt)
Remove and dispose of trash and debris onsite Daily - As needed maintenance
Maintenance Schedule for Qualifying Pervious Area (QPA)
Activity Schedule
Sweep impervious areas Between November 15th and December 15th (after leaf fall) During April (after snow melt)
Inspect QPA for erosion and loss of vegetation Annually - As needed maintenance
Remove and dispose of trash and debris onsite Annually - As needed maintenance
EX WATERSHED #1
EX WATERSHED #2
ANALYSIS POINT # 2
ANALYSIS POINT # 1
WATERSHED BOUNDARY
TIME OF CONCENTRATION FLOW PATH
FLOOD ZONE AE
REGULATORY FLOODWAY
PROPERTY LINE
LEGEND
EXISTING WATERSHED 1
EXISTING WATERSHED 2
1 01/08/25 TOWN COMMENTSHYDROLOGICAL SOIL GROUP BOUNDARY
15
15
31
24'±
20'
246
248250
250
248
246
244
242
240 238236234 234
236238
240
242
252
252 252252
250250248
246244
246244242240
238
236
234
232
230
228
220
222
224
226228 218
216
21
2
210
210
220
220218216
228
226
224
222
220
307 (HG D)
URBAN LAND
34B (HG A)
MERRIMAC FINE SANDY LOAM DD
ANALYSIS POINT # 1
WATERSHED BOUNDARY
TIME OF CONCENTRATION FLOW PATH
FLOOD ZONE AE
REGULATORY FLOODWAY
PROPERTY LINE
LEGEND
PR WATERSHED 1a
PR WATERSHED 1b
PR WATERSHED 2a
PR WATERSHED 2b
PROPOSED WATERSHED 1a
PROPOSED WATERSHED 1b
PROPOSED WATERSHED 2a
PROPOSED WATERSHED 2b
STORMWATER BASIN 1
STORMWATER BASIN 2
ANALYSIS POINT # 2
QUALIFYING PERVIOUS AREA
QUALIFYING PERVIOUS AREA
HYDROLOGICAL SOIL GROUP BOUNDARY 1 01/08/25 TOWN COMMENTS
CLA Engineers, Inc.
Civil · Structural · Survey
Appendix A
NRCS Soil Report
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
State of
Connecticut,
Eastern Part
7767F Rand Whiney
Natural
Resources
Conservation
Service
November 8, 2024
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
Soil Map..................................................................................................................5
Soil Map (7767F Rand Whitney)..........................................................................6
Legend..................................................................................................................7
Map Unit Legend (7767F Rand Whitney).............................................................8
Map Unit Descriptions (7767F Rand Whitney).....................................................8
State of Connecticut, Eastern Part..................................................................10
23A—Sudbury sandy loam, 0 to 5 percent slopes......................................10
34B—Merrimac fine sandy loam, 3 to 8 percent slopes..............................11
38C—Hinckley loamy sand, 3 to 15 percent slopes....................................13
75E—Hollis-Chatfield-Rock outcrop complex, 15 to 45 percent slopes......15
307—Urban land.........................................................................................18
W—Water....................................................................................................18
Soil Information for All Uses...............................................................................20
Soil Properties and Qualities..............................................................................20
Soil Qualities and Features.............................................................................20
Hydrologic Soil Group (7767F Rand Whitney)............................................20
References............................................................................................................25
4
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
5
6
Custom Soil Resource Report
Soil Map (7767F Rand Whitney)459287045929604593050459314045932304593320459287045929604593050459314045932304593320738510 738600 738690 738780 738870 738960 739050 739140 739230 739320
738510 738600 738690 738780 738870 738960 739050 739140 739230 739320
41° 27' 22'' N 72° 8' 40'' W41° 27' 22'' N72° 8' 4'' W41° 27' 5'' N
72° 8' 40'' W41° 27' 5'' N
72° 8' 4'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:3,830 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:12,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: State of Connecticut, Eastern Part
Survey Area Data: Version 2, Aug 30, 2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jun 14, 2022—Oct 6,
2022
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
7
Map Unit Legend (7767F Rand Whitney)
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
23A Sudbury sandy loam, 0 to 5
percent slopes
1.4 5.3%
34B Merrimac fine sandy loam, 3 to
8 percent slopes
5.1 18.6%
38C Hinckley loamy sand, 3 to 15
percent slopes
0.5 1.8%
75E Hollis-Chatfield-Rock outcrop
complex, 15 to 45 percent
slopes
0.4 1.4%
307 Urban land 7.0 25.4%
W Water 13.1 47.6%
Totals for Area of Interest 27.5 100.0%
Map Unit Descriptions (7767F Rand
Whitney)
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
Custom Soil Resource Report
8
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
Custom Soil Resource Report
9
State of Connecticut, Eastern Part
23A—Sudbury sandy loam, 0 to 5 percent slopes
Map Unit Setting
National map unit symbol: 9lkv
Elevation: 0 to 1,200 feet
Mean annual precipitation: 43 to 54 inches
Mean annual air temperature: 45 to 55 degrees F
Frost-free period: 140 to 185 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Sudbury and similar soils:80 percent
Minor components:20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Sudbury
Setting
Landform:Terraces, outwash plains
Down-slope shape:Concave
Across-slope shape:Linear
Parent material:Sandy and gravelly glaciofluvial deposits derived from granite
and/or schist and/or gneiss
Typical profile
Oe - 0 to 1 inches: moderately decomposed plant material
A - 1 to 5 inches: sandy loam
Bw1 - 5 to 17 inches: gravelly sandy loam
Bw2 - 17 to 25 inches: sandy loam
2C - 25 to 60 inches: stratified gravel to sand
Properties and qualities
Slope:0 to 5 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Moderately well drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat):High (1.98 to 5.95
in/hr)
Depth to water table:About 17 to 36 inches
Frequency of flooding:None
Frequency of ponding:None
Available water supply, 0 to 60 inches: Low (about 4.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2w
Hydrologic Soil Group: A/D
Ecological site: F144AY027MA - Moist Sandy Outwash
Hydric soil rating: No
Minor Components
Agawam
Percent of map unit:5 percent
Custom Soil Resource Report
10
Landform:Terraces, outwash plains
Down-slope shape:Linear
Across-slope shape:Linear
Hydric soil rating: No
Merrimac
Percent of map unit:5 percent
Landform:Terraces, outwash plains, kames
Down-slope shape:Linear
Across-slope shape:Linear
Hydric soil rating: No
Ninigret
Percent of map unit:5 percent
Landform:Terraces, outwash plains
Down-slope shape:Linear
Across-slope shape:Concave
Hydric soil rating: No
Tisbury
Percent of map unit:3 percent
Landform:Terraces, outwash plains
Down-slope shape:Concave
Across-slope shape:Linear
Hydric soil rating: No
Walpole
Percent of map unit:2 percent
Landform:Drainageways on terraces, depressions on terraces
Down-slope shape:Concave
Across-slope shape:Concave
Hydric soil rating: Yes
34B—Merrimac fine sandy loam, 3 to 8 percent slopes
Map Unit Setting
National map unit symbol: 2tyqs
Elevation: 0 to 1,290 feet
Mean annual precipitation: 36 to 71 inches
Mean annual air temperature: 39 to 55 degrees F
Frost-free period: 140 to 240 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Merrimac and similar soils:86 percent
Minor components:14 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Custom Soil Resource Report
11
Description of Merrimac
Setting
Landform:Outwash plains, outwash terraces, moraines, eskers, kames
Landform position (two-dimensional):Backslope, footslope, summit, shoulder
Landform position (three-dimensional):Side slope, crest, riser, tread
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Loamy glaciofluvial deposits derived from granite, schist, and
gneiss over sandy and gravelly glaciofluvial deposits derived from granite,
schist, and gneiss
Typical profile
Ap - 0 to 10 inches: fine sandy loam
Bw1 - 10 to 22 inches: fine sandy loam
Bw2 - 22 to 26 inches: stratified gravel to gravelly loamy sand
2C - 26 to 65 inches: stratified gravel to very gravelly sand
Properties and qualities
Slope:3 to 8 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Somewhat excessively drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very
high (1.42 to 99.90 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:2 percent
Maximum salinity:Nonsaline (0.0 to 1.4 mmhos/cm)
Sodium adsorption ratio, maximum:1.0
Available water supply, 0 to 60 inches: Low (about 4.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2s
Hydrologic Soil Group: A
Ecological site: F145XY008MA - Dry Outwash
Hydric soil rating: No
Minor Components
Sudbury
Percent of map unit:5 percent
Landform:Deltas, terraces, outwash plains
Landform position (two-dimensional):Footslope
Landform position (three-dimensional):Tread, dip
Down-slope shape:Concave
Across-slope shape:Linear
Hydric soil rating: No
Hinckley
Percent of map unit:5 percent
Landform:Deltas, kames, eskers, outwash plains
Landform position (two-dimensional):Summit, shoulder, backslope
Custom Soil Resource Report
12
Landform position (three-dimensional):Nose slope, side slope, crest, head slope,
rise
Down-slope shape:Convex
Across-slope shape:Convex, linear
Hydric soil rating: No
Windsor
Percent of map unit:3 percent
Landform:Dunes, deltas, outwash terraces, outwash plains
Landform position (two-dimensional):Summit
Landform position (three-dimensional):Tread, riser
Down-slope shape:Convex, linear
Across-slope shape:Convex, linear
Hydric soil rating: No
Walpole
Percent of map unit:1 percent
Landform:Depressions
Landform position (three-dimensional):Tread
Down-slope shape:Concave
Across-slope shape:Concave
Ecological site:F144AY028MA - Wet Outwash
Hydric soil rating: Yes
38C—Hinckley loamy sand, 3 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2svmb
Elevation: 0 to 1,290 feet
Mean annual precipitation: 36 to 71 inches
Mean annual air temperature: 39 to 55 degrees F
Frost-free period: 140 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Hinckley and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Hinckley
Setting
Landform:Outwash deltas, outwash terraces, moraines, eskers, kames, outwash
plains, kame terraces
Landform position (two-dimensional):Shoulder, backslope, footslope, toeslope,
summit
Landform position (three-dimensional):Nose slope, side slope, crest, head slope,
riser, tread
Down-slope shape:Concave, convex, linear
Across-slope shape:Convex, linear, concave
Custom Soil Resource Report
13
Parent material:Sandy and gravelly glaciofluvial deposits derived from gneiss
and/or granite and/or schist
Typical profile
Oe - 0 to 1 inches: moderately decomposed plant material
A - 1 to 8 inches: loamy sand
Bw1 - 8 to 11 inches: gravelly loamy sand
Bw2 - 11 to 16 inches: gravelly loamy sand
BC - 16 to 19 inches: very gravelly loamy sand
C - 19 to 65 inches: very gravelly sand
Properties and qualities
Slope:3 to 15 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Excessively drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very
high (1.42 to 99.90 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm)
Available water supply, 0 to 60 inches: Low (about 3.1 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: A
Ecological site: F144AY022MA - Dry Outwash
Hydric soil rating: No
Minor Components
Merrimac
Percent of map unit:5 percent
Landform:Kames, outwash plains, outwash terraces, moraines, eskers
Landform position (two-dimensional):Backslope, footslope, shoulder, toeslope,
summit
Landform position (three-dimensional):Side slope, crest, head slope, nose slope,
riser, tread
Down-slope shape:Convex
Across-slope shape:Convex
Hydric soil rating: No
Windsor
Percent of map unit:5 percent
Landform:Moraines, eskers, kames, outwash deltas, outwash terraces, outwash
plains, kame terraces
Landform position (two-dimensional):Shoulder, backslope, footslope, toeslope,
summit
Landform position (three-dimensional):Nose slope, side slope, crest, head slope,
riser, tread
Down-slope shape:Concave, convex, linear
Across-slope shape:Convex, linear, concave
Hydric soil rating: No
Custom Soil Resource Report
14
Agawam
Percent of map unit:3 percent
Landform:Outwash deltas, outwash terraces, moraines, eskers, kames, outwash
plains, kame terraces
Landform position (two-dimensional):Shoulder, backslope, toeslope, summit,
footslope
Landform position (three-dimensional):Nose slope, side slope, crest, head slope,
riser, tread
Down-slope shape:Concave, convex, linear
Across-slope shape:Convex, linear, concave
Hydric soil rating: No
Sudbury
Percent of map unit:2 percent
Landform:Outwash deltas, moraines, outwash plains, kame terraces, outwash
terraces
Landform position (two-dimensional):Backslope, footslope
Landform position (three-dimensional):Base slope, tread
Down-slope shape:Concave, linear
Across-slope shape:Concave, linear
Hydric soil rating: No
75E—Hollis-Chatfield-Rock outcrop complex, 15 to 45 percent slopes
Map Unit Setting
National map unit symbol: 9lqp
Elevation: 0 to 1,200 feet
Mean annual precipitation: 43 to 56 inches
Mean annual air temperature: 45 to 55 degrees F
Frost-free period: 140 to 185 days
Farmland classification: Not prime farmland
Map Unit Composition
Hollis and similar soils:35 percent
Chatfield and similar soils:30 percent
Rock outcrop:15 percent
Minor components:20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Hollis
Setting
Landform:Ridges, hills
Down-slope shape:Convex
Across-slope shape:Convex
Parent material:Loamy melt-out till derived from granite and/or schist and/or
gneiss
Typical profile
Oa - 0 to 1 inches: highly decomposed plant material
Custom Soil Resource Report
15
A - 1 to 6 inches: gravelly fine sandy loam
Bw1 - 6 to 9 inches: channery fine sandy loam
Bw2 - 9 to 15 inches: gravelly fine sandy loam
2R - 15 to 80 inches: bedrock
Properties and qualities
Slope:15 to 45 percent
Surface area covered with cobbles, stones or boulders:9.0 percent
Depth to restrictive feature:10 to 20 inches to lithic bedrock
Drainage class:Somewhat excessively drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat):Low to high (0.01 to
5.95 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Available water supply, 0 to 60 inches: Very low (about 1.8 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7s
Hydrologic Soil Group: D
Ecological site: F144AY033MA - Shallow Dry Till Uplands
Hydric soil rating: No
Description of Chatfield
Setting
Landform:Ridges, hills
Down-slope shape:Convex
Across-slope shape:Linear
Parent material:Coarse-loamy melt-out till derived from granite and/or schist
and/or gneiss
Typical profile
Oa - 0 to 1 inches: highly decomposed plant material
A - 1 to 6 inches: gravelly fine sandy loam
Bw1 - 6 to 15 inches: gravelly fine sandy loam
Bw2 - 15 to 29 inches: gravelly fine sandy loam
2R - 29 to 80 inches: unweathered bedrock
Properties and qualities
Slope:15 to 45 percent
Surface area covered with cobbles, stones or boulders:1.6 percent
Depth to restrictive feature:20 to 40 inches to lithic bedrock
Drainage class:Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat):Low to high (0.01 to
5.95 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Available water supply, 0 to 60 inches: Low (about 3.3 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7s
Custom Soil Resource Report
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Hydrologic Soil Group: B
Ecological site: F144AY034CT - Well Drained Till Uplands
Hydric soil rating: No
Description of Rock Outcrop
Typical profile
R - 0 to 0 inches: bedrock
Properties and qualities
Slope:15 to 45 percent
Depth to restrictive feature:0 inches to lithic bedrock
Runoff class: Very high
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8
Hydrologic Soil Group: D
Hydric soil rating: Unranked
Minor Components
Charlton
Percent of map unit:7 percent
Landform:Hills
Down-slope shape:Linear
Across-slope shape:Linear
Hydric soil rating: No
Leicester
Percent of map unit:5 percent
Landform:Drainageways, depressions
Down-slope shape:Linear
Across-slope shape:Concave
Hydric soil rating: Yes
Sutton, very stony
Percent of map unit:5 percent
Landform:Drainageways, depressions
Down-slope shape:Concave
Across-slope shape:Linear
Hydric soil rating: No
Unnamed, red parent material
Percent of map unit:1 percent
Hydric soil rating: No
Unnamed, sandy subsoil
Percent of map unit:1 percent
Hydric soil rating: No
Brimfield
Percent of map unit:1 percent
Landform:Ridges, hills
Down-slope shape:Convex
Across-slope shape:Convex
Hydric soil rating: No
Custom Soil Resource Report
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307—Urban land
Map Unit Setting
National map unit symbol: 9lmh
Elevation: 0 to 2,000 feet
Mean annual precipitation: 43 to 56 inches
Mean annual air temperature: 45 to 55 degrees F
Frost-free period: 120 to 185 days
Farmland classification: Not prime farmland
Map Unit Composition
Urban land:80 percent
Minor components:20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Urban Land
Typical profile
H - 0 to 6 inches: material
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8
Hydrologic Soil Group: D
Hydric soil rating: Unranked
Minor Components
Unnamed, undisturbed soils
Percent of map unit:10 percent
Hydric soil rating: No
Udorthents, wet substratum
Percent of map unit:10 percent
Down-slope shape:Convex
Across-slope shape:Linear
Hydric soil rating: No
W—Water
Map Unit Composition
Water:100 percent
Custom Soil Resource Report
18
Estimates are based on observations, descriptions, and transects of the mapunit.
Custom Soil Resource Report
19
Soil Information for All Uses
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and
qualities displayed as thematic maps with a summary table for the soil map units in
the selected area of interest. A single value or rating for each map unit is generated
by aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each property or quality.
Soil Qualities and Features
Soil qualities are behavior and performance attributes that are not directly
measured, but are inferred from observations of dynamic conditions and from soil
properties. Example soil qualities include natural drainage, and frost action. Soil
features are attributes that are not directly part of the soil. Example soil features
include slope and depth to restrictive layer. These features can greatly impact the
use and management of the soil.
Hydrologic Soil Group (7767F Rand Whitney)
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
20
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer at
or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Custom Soil Resource Report
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22
Custom Soil Resource Report
Map—Hydrologic Soil Group (7767F Rand Whitney)459287045929604593050459314045932304593320459287045929604593050459314045932304593320738510 738600 738690 738780 738870 738960 739050 739140 739230 739320
738510 738600 738690 738780 738870 738960 739050 739140 739230 739320
41° 27' 22'' N 72° 8' 40'' W41° 27' 22'' N72° 8' 4'' W41° 27' 5'' N
72° 8' 40'' W41° 27' 5'' N
72° 8' 4'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:3,830 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:12,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: State of Connecticut, Eastern Part
Survey Area Data: Version 2, Aug 30, 2024
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Jun 14, 2022—Oct 6,
2022
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
23
Table—Hydrologic Soil Group (7767F Rand Whitney)
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
23A Sudbury sandy loam, 0
to 5 percent slopes
A/D 1.4 5.3%
34B Merrimac fine sandy
loam, 3 to 8 percent
slopes
A 5.1 18.6%
38C Hinckley loamy sand, 3
to 15 percent slopes
A 0.5 1.8%
75E Hollis-Chatfield-Rock
outcrop complex, 15 to
45 percent slopes
D 0.4 1.4%
307 Urban land D 7.0 25.4%
W Water 13.1 47.6%
Totals for Area of Interest 27.5 100.0%
Rating Options—Hydrologic Soil Group (7767F Rand Whitney)
Aggregation Method: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Custom Soil Resource Report
24
References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
25
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
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CLA Engineers, Inc.
Civil · Structural · Survey
Appendix B
Hydrograph Reports – 2, 10 & 100-Year Frequencies
1 - Ex Watershed 1 2 - Ex Watershed 2
3 - Existing Conditions
4 - Pr Watershed 1a
5 - Basin 1
6 - Pr Watershed 1b
7 - Pr Watershed 1
8 - Pr Watershed 2a
9 - Basin 2
10 - Pr Watershed 2b
11 - Pr Watershed 2
12 - Proposed Conditions
1
Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Project: Analysis.gpw Tuesday, 01 / 14 / 2025
Hyd.Origin Description
Legend
1 SCS Runoff Ex Watershed 1
2 SCS Runoff Ex Watershed 2
3 Combine Existing Conditions
4 SCS Runoff Pr Watershed 1a
5 Reservoir Basin 1
6 SCS Runoff Pr Watershed 1b
7 Combine Pr Watershed 1
8 SCS Runoff Pr Watershed 2a
9 Reservoir Basin 2
10 SCS Runoff Pr Watershed 2b
11 Combine Pr Watershed 2
12 Combine Proposed Conditions
Hydraflow Table of Contents Analysis.gpw
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Watershed Model Schematic...................................................................................... 1
Hydrograph Return Period Recap............................................................................. 2
2 - Year
Summary Report......................................................................................................................... 3
Hydrograph Reports................................................................................................................... 4
Hydrograph No. 1, SCS Runoff, Ex Watershed 1..................................................................... 4
TR-55 Tc Worksheet............................................................................................................ 5
Precipitation Report............................................................................................................. 6
Hydrograph No. 2, SCS Runoff, Ex Watershed 2..................................................................... 7
TR-55 Tc Worksheet............................................................................................................ 8
Precipitation Report............................................................................................................. 9
Hydrograph No. 3, Combine, Existing Conditions.................................................................. 10
Hydrograph No. 4, SCS Runoff, Pr Watershed 1a................................................................. 11
TR-55 Tc Worksheet.......................................................................................................... 12
Precipitation Report...........................................................................................................13
Hydrograph No. 5, Reservoir, Basin 1.................................................................................... 14
Pond Report - Pond 1........................................................................................................ 15
Hydrograph No. 6, SCS Runoff, Pr Watershed 1b................................................................. 17
Precipitation Report...........................................................................................................18
Hydrograph No. 7, Combine, Pr Watershed 1........................................................................ 19
Hydrograph No. 8, SCS Runoff, Pr Watershed 2a................................................................. 20
TR-55 Tc Worksheet.......................................................................................................... 21
Precipitation Report...........................................................................................................22
Hydrograph No. 9, Reservoir, Basin 2.................................................................................... 23
Pond Report - Pond 2........................................................................................................ 24
Hydrograph No. 10, SCS Runoff, Pr Watershed 2b............................................................... 26
Precipitation Report...........................................................................................................27
Hydrograph No. 11, Combine, Pr Watershed 2...................................................................... 28
Hydrograph No. 12, Combine, Proposed Conditions............................................................. 29
10 - Year
Summary Report....................................................................................................................... 30
Hydrograph Reports................................................................................................................. 31
Hydrograph No. 1, SCS Runoff, Ex Watershed 1................................................................... 31
Precipitation Report...........................................................................................................32
Hydrograph No. 2, SCS Runoff, Ex Watershed 2................................................................... 33
Precipitation Report...........................................................................................................34
Hydrograph No. 3, Combine, Existing Conditions.................................................................. 35
Hydrograph No. 4, SCS Runoff, Pr Watershed 1a................................................................. 36
Precipitation Report...........................................................................................................37
Hydrograph No. 5, Reservoir, Basin 1.................................................................................... 38
Hydrograph No. 6, SCS Runoff, Pr Watershed 1b................................................................. 39
Precipitation Report...........................................................................................................40
Hydrograph No. 7, Combine, Pr Watershed 1........................................................................ 41
Hydrograph No. 8, SCS Runoff, Pr Watershed 2a................................................................. 42
Precipitation Report...........................................................................................................43
Contents continued...Analysis.gpw
Hydrograph No. 9, Reservoir, Basin 2.................................................................................... 44
Hydrograph No. 10, SCS Runoff, Pr Watershed 2b............................................................... 45
Precipitation Report...........................................................................................................46
Hydrograph No. 11, Combine, Pr Watershed 2...................................................................... 47
Hydrograph No. 12, Combine, Proposed Conditions............................................................. 48
25 - Year
Summary Report....................................................................................................................... 49
Hydrograph Reports................................................................................................................. 50
Hydrograph No. 1, SCS Runoff, Ex Watershed 1................................................................... 50
Precipitation Report...........................................................................................................51
Hydrograph No. 2, SCS Runoff, Ex Watershed 2................................................................... 52
Precipitation Report...........................................................................................................53
Hydrograph No. 3, Combine, Existing Conditions.................................................................. 54
Hydrograph No. 4, SCS Runoff, Pr Watershed 1a................................................................. 55
Precipitation Report...........................................................................................................56
Hydrograph No. 5, Reservoir, Basin 1.................................................................................... 57
Hydrograph No. 6, SCS Runoff, Pr Watershed 1b................................................................. 58
Precipitation Report...........................................................................................................59
Hydrograph No. 7, Combine, Pr Watershed 1........................................................................ 60
Hydrograph No. 8, SCS Runoff, Pr Watershed 2a................................................................. 61
Precipitation Report...........................................................................................................62
Hydrograph No. 9, Reservoir, Basin 2.................................................................................... 63
Hydrograph No. 10, SCS Runoff, Pr Watershed 2b............................................................... 64
Precipitation Report...........................................................................................................65
Hydrograph No. 11, Combine, Pr Watershed 2...................................................................... 66
Hydrograph No. 12, Combine, Proposed Conditions............................................................. 67
50 - Year
Summary Report....................................................................................................................... 68
Hydrograph Reports................................................................................................................. 69
Hydrograph No. 1, SCS Runoff, Ex Watershed 1................................................................... 69
Precipitation Report...........................................................................................................70
Hydrograph No. 2, SCS Runoff, Ex Watershed 2................................................................... 71
Precipitation Report...........................................................................................................72
Hydrograph No. 3, Combine, Existing Conditions.................................................................. 73
Hydrograph No. 4, SCS Runoff, Pr Watershed 1a................................................................. 74
Precipitation Report...........................................................................................................75
Hydrograph No. 5, Reservoir, Basin 1.................................................................................... 76
Hydrograph No. 6, SCS Runoff, Pr Watershed 1b................................................................. 77
Precipitation Report...........................................................................................................78
Hydrograph No. 7, Combine, Pr Watershed 1........................................................................ 79
Hydrograph No. 8, SCS Runoff, Pr Watershed 2a................................................................. 80
Precipitation Report...........................................................................................................81
Hydrograph No. 9, Reservoir, Basin 2.................................................................................... 82
Hydrograph No. 10, SCS Runoff, Pr Watershed 2b............................................................... 83
Precipitation Report...........................................................................................................84
Hydrograph No. 11, Combine, Pr Watershed 2...................................................................... 85
Hydrograph No. 12, Combine, Proposed Conditions............................................................. 86
100 - Year
Contents continued...Analysis.gpw
Summary Report....................................................................................................................... 87
Hydrograph Reports................................................................................................................. 88
Hydrograph No. 1, SCS Runoff, Ex Watershed 1................................................................... 88
Precipitation Report...........................................................................................................89
Hydrograph No. 2, SCS Runoff, Ex Watershed 2................................................................... 90
Precipitation Report...........................................................................................................91
Hydrograph No. 3, Combine, Existing Conditions.................................................................. 92
Hydrograph No. 4, SCS Runoff, Pr Watershed 1a................................................................. 93
Precipitation Report...........................................................................................................94
Hydrograph No. 5, Reservoir, Basin 1.................................................................................... 95
Hydrograph No. 6, SCS Runoff, Pr Watershed 1b................................................................. 96
Precipitation Report...........................................................................................................97
Hydrograph No. 7, Combine, Pr Watershed 1........................................................................ 98
Hydrograph No. 8, SCS Runoff, Pr Watershed 2a................................................................. 99
Precipitation Report......................................................................................................... 100
Hydrograph No. 9, Reservoir, Basin 2.................................................................................. 101
Hydrograph No. 10, SCS Runoff, Pr Watershed 2b............................................................. 102
Precipitation Report......................................................................................................... 103
Hydrograph No. 11, Combine, Pr Watershed 2.................................................................... 104
Hydrograph No. 12, Combine, Proposed Conditions........................................................... 105
IDF Report................................................................................................................ 106
Hydrograph Return Period Recap
2
Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph
No. type hyd(s)Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 SCS Runoff ------ ------- 0.000 ------- ------- 0.021 0.097 0.248 0.546 Ex Watershed 1
2 SCS Runoff ------ ------- 0.011 ------- ------- 0.243 0.773 1.395 2.205 Ex Watershed 2
3 Combine 1, 2 ------- 0.011 ------- ------- 0.243 0.860 1.637 2.721 Existing Conditions
4 SCS Runoff ------ ------- 1.897 ------- ------- 4.074 5.544 6.676 7.884 Pr Watershed 1a
5 Reservoir 4 ------- 0.000 ------- ------- 0.000 0.000 0.171 0.347 Basin 1
6 SCS Runoff ------ ------- 0.000 ------- ------- 0.007 0.035 0.092 0.169 Pr Watershed 1b
7 Combine 5, 6 ------- 0.000 ------- ------- 0.007 0.035 0.178 0.361 Pr Watershed 1
8 SCS Runoff ------ ------- 1.682 ------- ------- 3.256 4.280 5.058 5.880 Pr Watershed 2a
9 Reservoir 8 ------- 0.000 ------- ------- 0.093 0.353 0.767 1.615 Basin 2
10 SCS Runoff ------ ------- 0.519 ------- ------- 1.522 2.257 2.842 3.481 Pr Watershed 2b
11 Combine 9, 10 ------- 0.519 ------- ------- 1.522 2.257 2.842 3.481 Pr Watershed 2
12 Combine 7, 11 ------- 0.519 ------- ------- 1.522 2.289 2.935 3.648 Proposed Conditions
Proj. file: Analysis.gpw Tuesday, 01 / 14 / 2025
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hydrograph Summary Report
3
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.000 1 n/a 0 ------ ------ ------ Ex Watershed 1
2 SCS Runoff 0.011 1 1301 346 ------ ------ ------ Ex Watershed 2
3 Combine 0.011 1 1301 346 1, 2 ------ ------ Existing Conditions
4 SCS Runoff 1.897 1 733 7,988 ------ ------ ------ Pr Watershed 1a
5 Reservoir 0.000 1 n/a 0 4 232.23 7,988 Basin 1
6 SCS Runoff 0.000 1 1424 5 ------ ------ ------ Pr Watershed 1b
7 Combine 0.000 1 1424 5 5, 6 ------ ------ Pr Watershed 1
8 SCS Runoff 1.682 1 729 5,881 ------ ------ ------ Pr Watershed 2a
9 Reservoir 0.000 1 n/a 0 8 233.12 5,881 Basin 2
10 SCS Runoff 0.519 1 730 2,214 ------ ------ ------ Pr Watershed 2b
11 Combine 0.519 1 730 2,214 9, 10 ------ ------ Pr Watershed 2
12 Combine 0.519 1 730 2,219 7, 11 ------ ------ Proposed Conditions
Analysis.gpw Return Period: 2 Year Tuesday, 01 / 14 / 2025
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Hydrograph type = SCS Runoff Peak discharge = 0.000 cfs
Storm frequency = 2 yrs Time to peak = n/a
Time interval = 1 min Hyd. volume = 0 cuft
Drainage area = 1.420 ac Curve number = 36*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.30 min
Total precip. = 3.45 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.600 x 30) + (0.790 x 39) + (0.030 x 98)] / 1.420
4
0 10 20 30 40 50 60
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Ex Watershed 1
Hyd. No. 1 -- 2 Year
Hyd No. 1
TR55 Tc Worksheet 5
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hyd. No. 1
Ex Watershed 1
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 40.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.45 0.00 0.00
Land slope (%) = 1.10 0.00 0.00
Travel Time (min) = 8.39 + 0.00 + 0.00 = 8.39
Shallow Concentrated Flow
Flow length (ft) = 65.00 74.00 43.00
Watercourse slope (%) = 12.70 5.00 0.10
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =5.75 3.61 0.51
Travel Time (min) = 0.19 + 0.34 + 1.40 = 1.93
Channel Flow
X sectional flow area (sqft) = 0.00 0.00 0.00
Wetted perimeter (ft) = 0.00 0.00 0.00
Channel slope (%) = 0.00 0.00 0.00
Manning's n-value = 0.015 0.015 0.015
Velocity (ft/s) =0.00
0.00
0.00
Flow length (ft) ({0})0.0 0.0 0.0
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Total Travel Time, Tc .............................................................................. 10.30 min
Precipitation Report 6
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Storm Frequency = 2 yrs Time interval = 1 min
Total precip. = 3.4500 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 1 : Ex Watershed 1 - 2 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Hydrograph type = SCS Runoff Peak discharge = 0.011 cfs
Storm frequency = 2 yrs Time to peak = 1301 min
Time interval = 1 min Hyd. volume = 346 cuft
Drainage area = 2.890 ac Curve number = 42*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 20.40 min
Total precip. = 3.45 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(1.760 x 30) + (0.500 x 77) + (0.540 x 39) + (0.090 x 98)] / 2.890
7
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Ex Watershed 2
Hyd. No. 2 -- 2 Year
Hyd No. 2
TR55 Tc Worksheet 8
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hyd. No. 2
Ex Watershed 2
Description A B C Totals
Sheet Flow
Manning's n-value = 0.240 0.011 0.011
Flow length (ft) = 138.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.45 0.00 0.00
Land slope (%) = 2.40 0.00 0.00
Travel Time (min) = 16.53 + 0.00 + 0.00 = 16.53
Shallow Concentrated Flow
Flow length (ft) = 80.00 200.00 181.00
Watercourse slope (%) = 6.00 2.40 1.90
Surface description = Unpaved Unpaved Unpaved
Average velocity (ft/s) =3.95 2.50 2.22
Travel Time (min) = 0.34 + 1.33 + 1.36 = 3.03
Channel Flow
X sectional flow area (sqft) = 13.00 0.00 0.00
Wetted perimeter (ft) = 15.00 0.00 0.00
Channel slope (%) = 3.10 0.00 0.00
Manning's n-value = 0.040 0.015 0.015
Velocity (ft/s) =5.96
0.00
0.00
Flow length (ft) ({0})311.0 0.0 0.0
Travel Time (min) = 0.87 + 0.00 + 0.00 = 0.87
Total Travel Time, Tc .............................................................................. 20.40 min
Precipitation Report 9
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Storm Frequency = 2 yrs Time interval = 1 min
Total precip. = 3.4500 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 2 : Ex Watershed 2 - 2 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 3
Existing Conditions
Hydrograph type = Combine Peak discharge = 0.011 cfs
Storm frequency = 2 yrs Time to peak = 1301 min
Time interval = 1 min Hyd. volume = 346 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 4.310 ac
10
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Existing Conditions
Hyd. No. 3 -- 2 Year
Hyd No. 3 Hyd No. 1 Hyd No. 2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Hydrograph type = SCS Runoff Peak discharge = 1.897 cfs
Storm frequency = 2 yrs Time to peak = 733 min
Time interval = 1 min Hyd. volume = 7,988 cuft
Drainage area = 1.920 ac Curve number = 73*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 14.50 min
Total precip. = 3.45 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.810 x 39) + (1.110 x 98)] / 1.920
11
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Pr Watershed 1a
Hyd. No. 4 -- 2 Year
Hyd No. 4
TR55 Tc Worksheet 12
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hyd. No. 4
Pr Watershed 1a
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 151.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.45 0.00 0.00
Land slope (%) = 3.70 0.00 0.00
Travel Time (min) = 1.27 + 0.00 + 0.00 = 1.27
Shallow Concentrated Flow
Flow length (ft) = 0.00 0.00 0.00
Watercourse slope (%) = 0.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) =0.00 0.00 0.00
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Channel Flow
X sectional flow area (sqft) = 5.00 0.00 0.00
Wetted perimeter (ft) = 8.00 0.00 0.00
Channel slope (%) = 0.40 0.00 0.00
Manning's n-value = 0.400 0.015 0.015
Velocity (ft/s) =0.17
0.00
0.00
Flow length (ft) ({0})136.0 0.0 0.0
Travel Time (min) = 13.18 + 0.00 + 0.00 = 13.18
Total Travel Time, Tc .............................................................................. 14.50 min
Precipitation Report 13
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Storm Frequency = 2 yrs Time interval = 1 min
Total precip. = 3.4500 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 4 : Pr Watershed 1a - 2 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 5
Basin 1
Hydrograph type = Reservoir Peak discharge = 0.000 cfs
Storm frequency = 2 yrs Time to peak = n/a
Time interval = 1 min Hyd. volume = 0 cuft
Inflow hyd. No. = 4 - Pr Watershed 1a Max. Elevation = 232.23 ft
Reservoir name = Pond 1 Max. Storage = 7,988 cuft
Storage Indication method used.
14
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Basin 1
Hyd. No. 5 -- 2 Year
Hyd No. 5 Hyd No. 4 Total storage used = 7,988 cuft
Pond Report 15
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Pond No. 1 - Pond 1
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 231.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00 231.00 5,359 0 0
1.00 232.00 7,040 6,180 6,180
2.00 233.00 8,883 7,943 14,123
3.00 234.00 11,264 10,049 24,172
4.00 235.00 13,394 12,312 36,484
Culvert / Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise (in)= 0.00 0.00 0.00 0.00
Span (in)= 0.00 0.00 0.00 0.00
No. Barrels = 0 000
Invert El. (ft)= 0.00 0.00 0.00 0.00
Length (ft)= 0.00 0.00 0.00 0.00
Slope (%)= 0.00 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff.= 0.60 0.60 0.60 0.60
Multi-Stage = n/a NoNoNo
Crest Len (ft)= 8.00 0.00 0.00 0.00
Crest El. (ft)= 234.00 0.00 0.00 0.00
Weir Coeff.= 3.33 3.33 3.33 3.33
Weir Type = Rect --- --- ---
Multi-Stage = No No No No
Exfil.(in/hr)= 0.000 (by Wet area)
TW Elev. (ft)= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage / Storage / Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 231.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.10 618 231.10 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.20 1,236 231.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.30 1,854 231.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.40 2,472 231.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.50 3,090 231.50 --- --- --- --- 0.00 --- --- --- --- --- 0.0000.60 3,708 231.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.70 4,326 231.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.80 4,944 231.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.90 5,562 231.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.00 6,180 232.00 --- --- --- --- 0.00 --- --- --- --- --- 0.0001.10 6,974 232.10 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.20 7,768 232.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.30 8,563 232.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.40 9,357 232.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.50 10,151 232.50 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.60 10,946 232.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.70 11,740 232.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.80 12,534 232.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.90 13,328 232.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.00 14,123 233.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.10 15,128 233.10 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.20 16,132 233.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.30 17,137 233.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.40 18,142 233.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.50 19,147 233.50 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.60 20,152 233.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.70 21,157 233.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.80 22,162 233.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.90 23,167 233.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000
3.00 24,172 234.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000
3.10 25,403 234.10 --- --- --- --- 0.84 --- --- --- --- --- 0.8433.20 26,634 234.20 --- --- --- --- 2.38 --- --- --- --- --- 2.383
3.30 27,865 234.30 --- --- --- --- 4.38 --- --- --- --- --- 4.377
3.40 29,097 234.40 --- --- --- --- 6.74 --- --- --- --- --- 6.739
3.50 30,328 234.50 --- --- --- --- 9.42 --- --- --- --- --- 9.419
3.60 31,559 234.60 --- --- --- --- 12.38 --- --- --- --- --- 12.38
3.70 32,790 234.70 --- --- --- --- 15.60 --- --- --- --- --- 15.60
Continues on next page...
16
Pond 1
Stage / Storage / Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
3.80 34,022 234.80 --- --- --- --- 19.06 --- --- --- --- --- 19.06
3.90 35,253 234.90 --- --- --- --- 22.75 --- --- --- --- --- 22.75
4.00 36,484 235.00 --- --- --- --- 26.64 --- --- --- --- --- 26.64
...End
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Hydrograph type = SCS Runoff Peak discharge = 0.000 cfs
Storm frequency = 2 yrs Time to peak = 1424 min
Time interval = 1 min Hyd. volume = 5 cuft
Drainage area = 0.190 ac Curve number = 39*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 3.45 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.190 x 39)] / 0.190
17
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1b
Hyd. No. 6 -- 2 Year
Hyd No. 6
Precipitation Report 18
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Storm Frequency = 2 yrs Time interval = 1 min
Total precip. = 3.4500 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 6 : Pr Watershed 1b - 2 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 7
Pr Watershed 1
Hydrograph type = Combine Peak discharge = 0.000 cfs
Storm frequency = 2 yrs Time to peak = 1424 min
Time interval = 1 min Hyd. volume = 5 cuft
Inflow hyds. = 5, 6 Contrib. drain. area = 0.190 ac
19
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1
Hyd. No. 7 -- 2 Year
Hyd No. 7 Hyd No. 5 Hyd No. 6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Hydrograph type = SCS Runoff Peak discharge = 1.682 cfs
Storm frequency = 2 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 5,881 cuft
Drainage area = 1.110 ac Curve number = 78*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.80 min
Total precip. = 3.45 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.370 x 39) + (0.740 x 98)] / 1.110
20
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Pr Watershed 2a
Hyd. No. 8 -- 2 Year
Hyd No. 8
TR55 Tc Worksheet 21
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hyd. No. 8
Pr Watershed 2a
Description A B C Totals
Sheet Flow
Manning's n-value = 0.011 0.011 0.011
Flow length (ft) = 132.0 0.0 0.0
Two-year 24-hr precip. (in) = 3.45 0.00 0.00
Land slope (%) = 3.00 0.00 0.00
Travel Time (min) = 1.24 + 0.00 + 0.00 = 1.24
Shallow Concentrated Flow
Flow length (ft) = 0.00 0.00 0.00
Watercourse slope (%) = 0.00 0.00 0.00
Surface description = Paved Paved Paved
Average velocity (ft/s) =0.00 0.00 0.00
Travel Time (min) = 0.00 + 0.00 + 0.00 = 0.00
Channel Flow
X sectional flow area (sqft) = 5.00 5.00 0.00
Wetted perimeter (ft) = 8.00 8.00 0.00
Channel slope (%) = 2.80 1.30 0.00
Manning's n-value = 0.400 0.400 0.015
Velocity (ft/s) =0.45
0.31
0.00
Flow length (ft) ({0})120.0 58.0 0.0
Travel Time (min) = 4.40 + 3.12 + 0.00 = 7.51
Total Travel Time, Tc .............................................................................. 8.80 min
Precipitation Report 22
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Storm Frequency = 2 yrs Time interval = 1 min
Total precip. = 3.4500 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 8 : Pr Watershed 2a - 2 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 9
Basin 2
Hydrograph type = Reservoir Peak discharge = 0.000 cfs
Storm frequency = 2 yrs Time to peak = n/a
Time interval = 1 min Hyd. volume = 0 cuft
Inflow hyd. No. = 8 - Pr Watershed 2a Max. Elevation = 233.12 ft
Reservoir name = Pond 2 Max. Storage = 5,881 cuft
Storage Indication method used.
23
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Basin 2
Hyd. No. 9 -- 2 Year
Hyd No. 9 Hyd No. 8 Total storage used = 5,881 cuft
Pond Report 24
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Pond No. 2 - Pond 2
Pond Data
Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 231.00 ft
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft)
0.00 231.00 1,906 0 0
1.00 232.00 2,680 2,282 2,282
2.00 233.00 3,551 3,105 5,387
3.00 234.00 4,734 4,128 9,515
4.00 235.00 5,671 5,195 14,710
Culvert / Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise (in)= 0.00 0.00 0.00 0.00
Span (in)= 0.00 0.00 0.00 0.00
No. Barrels = 0 000
Invert El. (ft)= 0.00 0.00 0.00 0.00
Length (ft)= 0.00 0.00 0.00 0.00
Slope (%)= 0.00 0.00 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff.= 0.60 0.60 0.60 0.60
Multi-Stage = n/a NoNoNo
Crest Len (ft)= 8.00 0.00 0.00 0.00
Crest El. (ft)= 234.00 0.00 0.00 0.00
Weir Coeff.= 3.33 3.33 3.33 3.33
Weir Type = Rect --- --- ---
Multi-Stage = No No No No
Exfil.(in/hr)= 0.000 (by Wet area)
TW Elev. (ft)= 0.00
Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s).
Stage / Storage / Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 231.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.10 228 231.10 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.20 456 231.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.30 685 231.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.40 913 231.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.50 1,141 231.50 --- --- --- --- 0.00 --- --- --- --- --- 0.0000.60 1,369 231.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.70 1,597 231.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.80 1,825 231.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000
0.90 2,054 231.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.00 2,282 232.00 --- --- --- --- 0.00 --- --- --- --- --- 0.0001.10 2,592 232.10 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.20 2,903 232.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.30 3,213 232.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.40 3,524 232.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.50 3,834 232.50 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.60 4,145 232.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.70 4,455 232.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.80 4,766 232.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000
1.90 5,076 232.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.00 5,387 233.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.10 5,800 233.10 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.20 6,212 233.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.30 6,625 233.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.40 7,038 233.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.50 7,451 233.50 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.60 7,864 233.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.70 8,276 233.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.80 8,689 233.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000
2.90 9,102 233.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000
3.00 9,515 234.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000
3.10 10,034 234.10 --- --- --- --- 0.84 --- --- --- --- --- 0.8433.20 10,554 234.20 --- --- --- --- 2.38 --- --- --- --- --- 2.383
3.30 11,073 234.30 --- --- --- --- 4.38 --- --- --- --- --- 4.378
3.40 11,593 234.40 --- --- --- --- 6.74 --- --- --- --- --- 6.740
3.50 12,112 234.50 --- --- --- --- 9.42 --- --- --- --- --- 9.420
3.60 12,632 234.60 --- --- --- --- 12.38 --- --- --- --- --- 12.38
3.70 13,151 234.70 --- --- --- --- 15.60 --- --- --- --- --- 15.60
Continues on next page...
25
Pond 2
Stage / Storage / Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
3.80 13,671 234.80 --- --- --- --- 19.06 --- --- --- --- --- 19.06
3.90 14,190 234.90 --- --- --- --- 22.75 --- --- --- --- --- 22.75
4.00 14,710 235.00 --- --- --- --- 26.64 --- --- --- --- --- 26.64
...End
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Hydrograph type = SCS Runoff Peak discharge = 0.519 cfs
Storm frequency = 2 yrs Time to peak = 730 min
Time interval = 1 min Hyd. volume = 2,214 cuft
Drainage area = 0.960 ac Curve number = 63*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 3.45 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.120 x 30) + (0.040 x 77) + (0.230 x 39) + (0.280 x 80) + (0.290 x 77)] / 0.960
26
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.10 0.10
0.20 0.20
0.30 0.30
0.40 0.40
0.50 0.50
0.60 0.60
0.70 0.70
0.80 0.80
0.90 0.90
1.00 1.00
Q (cfs)
Time (min)
Pr Watershed 2b
Hyd. No. 10 -- 2 Year
Hyd No. 10
Precipitation Report 27
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Storm Frequency = 2 yrs Time interval = 1 min
Total precip. = 3.4500 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 10 : Pr Watershed 2b - 2 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 11
Pr Watershed 2
Hydrograph type = Combine Peak discharge = 0.519 cfs
Storm frequency = 2 yrs Time to peak = 730 min
Time interval = 1 min Hyd. volume = 2,214 cuft
Inflow hyds. = 9, 10 Contrib. drain. area = 0.960 ac
28
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.10 0.10
0.20 0.20
0.30 0.30
0.40 0.40
0.50 0.50
0.60 0.60
0.70 0.70
0.80 0.80
0.90 0.90
1.00 1.00
Q (cfs)
Time (min)
Pr Watershed 2
Hyd. No. 11 -- 2 Year
Hyd No. 11 Hyd No. 9 Hyd No. 10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 12
Proposed Conditions
Hydrograph type = Combine Peak discharge = 0.519 cfs
Storm frequency = 2 yrs Time to peak = 730 min
Time interval = 1 min Hyd. volume = 2,219 cuft
Inflow hyds. = 7, 11 Contrib. drain. area = 0.000 ac
29
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.10 0.10
0.20 0.20
0.30 0.30
0.40 0.40
0.50 0.50
0.60 0.60
0.70 0.70
0.80 0.80
0.90 0.90
1.00 1.00
Q (cfs)
Time (min)
Proposed Conditions
Hyd. No. 12 -- 2 Year
Hyd No. 12 Hyd No. 7 Hyd No. 11
Hydrograph Summary Report
30
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.021 1 863 664 ------ ------ ------ Ex Watershed 1
2 SCS Runoff 0.243 1 757 3,641 ------ ------ ------ Ex Watershed 2
3 Combine 0.243 1 757 4,305 1, 2 ------ ------ Existing Conditions
4 SCS Runoff 4.074 1 732 16,552 ------ ------ ------ Pr Watershed 1a
5 Reservoir 0.000 1 n/a 0 4 233.24 16,552 Basin 1
6 SCS Runoff 0.007 1 775 160 ------ ------ ------ Pr Watershed 1b
7 Combine 0.007 1 775 160 5, 6 ------ ------ Pr Watershed 1
8 SCS Runoff 3.256 1 729 11,338 ------ ------ ------ Pr Watershed 2a
9 Reservoir 0.093 1 1061 1,823 8 234.01 9,572 Basin 2
10 SCS Runoff 1.522 1 729 5,525 ------ ------ ------ Pr Watershed 2b
11 Combine 1.522 1 729 7,347 9, 10 ------ ------ Pr Watershed 2
12 Combine 1.522 1 729 7,507 7, 11 ------ ------ Proposed Conditions
Analysis.gpw Return Period: 10 Year Tuesday, 01 / 14 / 2025
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Hydrograph type = SCS Runoff Peak discharge = 0.021 cfs
Storm frequency = 10 yrs Time to peak = 863 min
Time interval = 1 min Hyd. volume = 664 cuft
Drainage area = 1.420 ac Curve number = 36*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.30 min
Total precip. = 5.12 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.600 x 30) + (0.790 x 39) + (0.030 x 98)] / 1.420
31
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Ex Watershed 1
Hyd. No. 1 -- 10 Year
Hyd No. 1
Precipitation Report 32
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Storm Frequency = 10 yrs Time interval = 1 min
Total precip. = 5.1200 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 1 : Ex Watershed 1 - 10 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Hydrograph type = SCS Runoff Peak discharge = 0.243 cfs
Storm frequency = 10 yrs Time to peak = 757 min
Time interval = 1 min Hyd. volume = 3,641 cuft
Drainage area = 2.890 ac Curve number = 42*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 20.40 min
Total precip. = 5.12 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(1.760 x 30) + (0.500 x 77) + (0.540 x 39) + (0.090 x 98)] / 2.890
33
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Q (cfs)
Time (min)
Ex Watershed 2
Hyd. No. 2 -- 10 Year
Hyd No. 2
Precipitation Report 34
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Storm Frequency = 10 yrs Time interval = 1 min
Total precip. = 5.1200 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 2 : Ex Watershed 2 - 10 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 3
Existing Conditions
Hydrograph type = Combine Peak discharge = 0.243 cfs
Storm frequency = 10 yrs Time to peak = 757 min
Time interval = 1 min Hyd. volume = 4,305 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 4.310 ac
35
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Q (cfs)
Time (min)
Existing Conditions
Hyd. No. 3 -- 10 Year
Hyd No. 3 Hyd No. 1 Hyd No. 2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Hydrograph type = SCS Runoff Peak discharge = 4.074 cfs
Storm frequency = 10 yrs Time to peak = 732 min
Time interval = 1 min Hyd. volume = 16,552 cuft
Drainage area = 1.920 ac Curve number = 73*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 14.50 min
Total precip. = 5.12 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.810 x 39) + (1.110 x 98)] / 1.920
36
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
Q (cfs)
Time (min)
Pr Watershed 1a
Hyd. No. 4 -- 10 Year
Hyd No. 4
Precipitation Report 37
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Storm Frequency = 10 yrs Time interval = 1 min
Total precip. = 5.1200 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 4 : Pr Watershed 1a - 10 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 5
Basin 1
Hydrograph type = Reservoir Peak discharge = 0.000 cfs
Storm frequency = 10 yrs Time to peak = n/a
Time interval = 1 min Hyd. volume = 0 cuft
Inflow hyd. No. = 4 - Pr Watershed 1a Max. Elevation = 233.24 ft
Reservoir name = Pond 1 Max. Storage = 16,552 cuft
Storage Indication method used.
38
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
Q (cfs)
Time (min)
Basin 1
Hyd. No. 5 -- 10 Year
Hyd No. 5 Hyd No. 4 Total storage used = 16,552 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Hydrograph type = SCS Runoff Peak discharge = 0.007 cfs
Storm frequency = 10 yrs Time to peak = 775 min
Time interval = 1 min Hyd. volume = 160 cuft
Drainage area = 0.190 ac Curve number = 39*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 5.12 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.190 x 39)] / 0.190
39
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1b
Hyd. No. 6 -- 10 Year
Hyd No. 6
Precipitation Report 40
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Storm Frequency = 10 yrs Time interval = 1 min
Total precip. = 5.1200 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 6 : Pr Watershed 1b - 10 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 7
Pr Watershed 1
Hydrograph type = Combine Peak discharge = 0.007 cfs
Storm frequency = 10 yrs Time to peak = 775 min
Time interval = 1 min Hyd. volume = 160 cuft
Inflow hyds. = 5, 6 Contrib. drain. area = 0.190 ac
41
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1
Hyd. No. 7 -- 10 Year
Hyd No. 7 Hyd No. 5 Hyd No. 6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Hydrograph type = SCS Runoff Peak discharge = 3.256 cfs
Storm frequency = 10 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 11,338 cuft
Drainage area = 1.110 ac Curve number = 78*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.80 min
Total precip. = 5.12 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.370 x 39) + (0.740 x 98)] / 1.110
42
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
Q (cfs)
Time (min)
Pr Watershed 2a
Hyd. No. 8 -- 10 Year
Hyd No. 8
Precipitation Report 43
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Storm Frequency = 10 yrs Time interval = 1 min
Total precip. = 5.1200 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 8 : Pr Watershed 2a - 10 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 9
Basin 2
Hydrograph type = Reservoir Peak discharge = 0.093 cfs
Storm frequency = 10 yrs Time to peak = 1061 min
Time interval = 1 min Hyd. volume = 1,823 cuft
Inflow hyd. No. = 8 - Pr Watershed 2a Max. Elevation = 234.01 ft
Reservoir name = Pond 2 Max. Storage = 9,572 cuft
Storage Indication method used.
44
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
Q (cfs)
Time (min)
Basin 2
Hyd. No. 9 -- 10 Year
Hyd No. 9 Hyd No. 8 Total storage used = 9,572 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Hydrograph type = SCS Runoff Peak discharge = 1.522 cfs
Storm frequency = 10 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 5,525 cuft
Drainage area = 0.960 ac Curve number = 63*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 5.12 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.120 x 30) + (0.040 x 77) + (0.230 x 39) + (0.280 x 80) + (0.290 x 77)] / 0.960
45
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Pr Watershed 2b
Hyd. No. 10 -- 10 Year
Hyd No. 10
Precipitation Report 46
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Storm Frequency = 10 yrs Time interval = 1 min
Total precip. = 5.1200 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 10 : Pr Watershed 2b - 10 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 11
Pr Watershed 2
Hydrograph type = Combine Peak discharge = 1.522 cfs
Storm frequency = 10 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 7,347 cuft
Inflow hyds. = 9, 10 Contrib. drain. area = 0.960 ac
47
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Pr Watershed 2
Hyd. No. 11 -- 10 Year
Hyd No. 11 Hyd No. 9 Hyd No. 10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 12
Proposed Conditions
Hydrograph type = Combine Peak discharge = 1.522 cfs
Storm frequency = 10 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 7,507 cuft
Inflow hyds. = 7, 11 Contrib. drain. area = 0.000 ac
48
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Proposed Conditions
Hyd. No. 12 -- 10 Year
Hyd No. 12 Hyd No. 7 Hyd No. 11
Hydrograph Summary Report
49
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.097 1 754 1,746 ------ ------ ------ Ex Watershed 1
2 SCS Runoff 0.773 1 745 7,107 ------ ------ ------ Ex Watershed 2
3 Combine 0.860 1 746 8,853 1, 2 ------ ------ Existing Conditions
4 SCS Runoff 5.544 1 732 22,455 ------ ------ ------ Pr Watershed 1a
5 Reservoir 0.000 1 n/a 0 4 233.83 22,455 Basin 1
6 SCS Runoff 0.035 1 732 350 ------ ------ ------ Pr Watershed 1b
7 Combine 0.035 1 732 350 5, 6 ------ ------ Pr Watershed 1
8 SCS Runoff 4.280 1 729 14,991 ------ ------ ------ Pr Watershed 2a
9 Reservoir 0.353 1 813 5,476 8 234.04 9,733 Basin 2
10 SCS Runoff 2.257 1 729 7,976 ------ ------ ------ Pr Watershed 2b
11 Combine 2.257 1 729 13,453 9, 10 ------ ------ Pr Watershed 2
12 Combine 2.289 1 729 13,803 7, 11 ------ ------ Proposed Conditions
Analysis.gpw Return Period: 25 Year Tuesday, 01 / 14 / 2025
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Hydrograph type = SCS Runoff Peak discharge = 0.097 cfs
Storm frequency = 25 yrs Time to peak = 754 min
Time interval = 1 min Hyd. volume = 1,746 cuft
Drainage area = 1.420 ac Curve number = 36*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.30 min
Total precip. = 6.16 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.600 x 30) + (0.790 x 39) + (0.030 x 98)] / 1.420
50
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Ex Watershed 1
Hyd. No. 1 -- 25 Year
Hyd No. 1
Precipitation Report 51
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Storm Frequency = 25 yrs Time interval = 1 min
Total precip. = 6.1600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 1 : Ex Watershed 1 - 25 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Hydrograph type = SCS Runoff Peak discharge = 0.773 cfs
Storm frequency = 25 yrs Time to peak = 745 min
Time interval = 1 min Hyd. volume = 7,107 cuft
Drainage area = 2.890 ac Curve number = 42*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 20.40 min
Total precip. = 6.16 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(1.760 x 30) + (0.500 x 77) + (0.540 x 39) + (0.090 x 98)] / 2.890
52
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.10 0.10
0.20 0.20
0.30 0.30
0.40 0.40
0.50 0.50
0.60 0.60
0.70 0.70
0.80 0.80
0.90 0.90
1.00 1.00
Q (cfs)
Time (min)
Ex Watershed 2
Hyd. No. 2 -- 25 Year
Hyd No. 2
Precipitation Report 53
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Storm Frequency = 25 yrs Time interval = 1 min
Total precip. = 6.1600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 2 : Ex Watershed 2 - 25 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 3
Existing Conditions
Hydrograph type = Combine Peak discharge = 0.860 cfs
Storm frequency = 25 yrs Time to peak = 746 min
Time interval = 1 min Hyd. volume = 8,853 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 4.310 ac
54
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.10 0.10
0.20 0.20
0.30 0.30
0.40 0.40
0.50 0.50
0.60 0.60
0.70 0.70
0.80 0.80
0.90 0.90
1.00 1.00
Q (cfs)
Time (min)
Existing Conditions
Hyd. No. 3 -- 25 Year
Hyd No. 3 Hyd No. 1 Hyd No. 2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Hydrograph type = SCS Runoff Peak discharge = 5.544 cfs
Storm frequency = 25 yrs Time to peak = 732 min
Time interval = 1 min Hyd. volume = 22,455 cuft
Drainage area = 1.920 ac Curve number = 73*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 14.50 min
Total precip. = 6.16 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.810 x 39) + (1.110 x 98)] / 1.920
55
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (min)
Pr Watershed 1a
Hyd. No. 4 -- 25 Year
Hyd No. 4
Precipitation Report 56
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Storm Frequency = 25 yrs Time interval = 1 min
Total precip. = 6.1600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 4 : Pr Watershed 1a - 25 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 5
Basin 1
Hydrograph type = Reservoir Peak discharge = 0.000 cfs
Storm frequency = 25 yrs Time to peak = n/a
Time interval = 1 min Hyd. volume = 0 cuft
Inflow hyd. No. = 4 - Pr Watershed 1a Max. Elevation = 233.83 ft
Reservoir name = Pond 1 Max. Storage = 22,455 cuft
Storage Indication method used.
57
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (min)
Basin 1
Hyd. No. 5 -- 25 Year
Hyd No. 5 Hyd No. 4 Total storage used = 22,455 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Hydrograph type = SCS Runoff Peak discharge = 0.035 cfs
Storm frequency = 25 yrs Time to peak = 732 min
Time interval = 1 min Hyd. volume = 350 cuft
Drainage area = 0.190 ac Curve number = 39*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.16 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.190 x 39)] / 0.190
58
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1b
Hyd. No. 6 -- 25 Year
Hyd No. 6
Precipitation Report 59
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Storm Frequency = 25 yrs Time interval = 1 min
Total precip. = 6.1600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 6 : Pr Watershed 1b - 25 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 7
Pr Watershed 1
Hydrograph type = Combine Peak discharge = 0.035 cfs
Storm frequency = 25 yrs Time to peak = 732 min
Time interval = 1 min Hyd. volume = 350 cuft
Inflow hyds. = 5, 6 Contrib. drain. area = 0.190 ac
60
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1
Hyd. No. 7 -- 25 Year
Hyd No. 7 Hyd No. 5 Hyd No. 6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Hydrograph type = SCS Runoff Peak discharge = 4.280 cfs
Storm frequency = 25 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 14,991 cuft
Drainage area = 1.110 ac Curve number = 78*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.80 min
Total precip. = 6.16 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.370 x 39) + (0.740 x 98)] / 1.110
61
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
Q (cfs)
Time (min)
Pr Watershed 2a
Hyd. No. 8 -- 25 Year
Hyd No. 8
Precipitation Report 62
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Storm Frequency = 25 yrs Time interval = 1 min
Total precip. = 6.1600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 8 : Pr Watershed 2a - 25 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 9
Basin 2
Hydrograph type = Reservoir Peak discharge = 0.353 cfs
Storm frequency = 25 yrs Time to peak = 813 min
Time interval = 1 min Hyd. volume = 5,476 cuft
Inflow hyd. No. = 8 - Pr Watershed 2a Max. Elevation = 234.04 ft
Reservoir name = Pond 2 Max. Storage = 9,733 cuft
Storage Indication method used.
63
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
Q (cfs)
Time (min)
Basin 2
Hyd. No. 9 -- 25 Year
Hyd No. 9 Hyd No. 8 Total storage used = 9,733 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Hydrograph type = SCS Runoff Peak discharge = 2.257 cfs
Storm frequency = 25 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 7,976 cuft
Drainage area = 0.960 ac Curve number = 63*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 6.16 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.120 x 30) + (0.040 x 77) + (0.230 x 39) + (0.280 x 80) + (0.290 x 77)] / 0.960
64
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Pr Watershed 2b
Hyd. No. 10 -- 25 Year
Hyd No. 10
Precipitation Report 65
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Storm Frequency = 25 yrs Time interval = 1 min
Total precip. = 6.1600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 10 : Pr Watershed 2b - 25 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 11
Pr Watershed 2
Hydrograph type = Combine Peak discharge = 2.257 cfs
Storm frequency = 25 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 13,453 cuft
Inflow hyds. = 9, 10 Contrib. drain. area = 0.960 ac
66
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Pr Watershed 2
Hyd. No. 11 -- 25 Year
Hyd No. 11 Hyd No. 9 Hyd No. 10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 12
Proposed Conditions
Hydrograph type = Combine Peak discharge = 2.289 cfs
Storm frequency = 25 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 13,803 cuft
Inflow hyds. = 7, 11 Contrib. drain. area = 0.000 ac
67
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Proposed Conditions
Hyd. No. 12 -- 25 Year
Hyd No. 12 Hyd No. 7 Hyd No. 11
Hydrograph Summary Report
68
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.248 1 739 2,840 ------ ------ ------ Ex Watershed 1
2 SCS Runoff 1.395 1 742 10,279 ------ ------ ------ Ex Watershed 2
3 Combine 1.637 1 741 13,119 1, 2 ------ ------ Existing Conditions
4 SCS Runoff 6.676 1 732 27,067 ------ ------ ------ Pr Watershed 1a
5 Reservoir 0.171 1 1241 2,894 4 234.02 24,421 Basin 1
6 SCS Runoff 0.092 1 729 531 ------ ------ ------ Pr Watershed 1b
7 Combine 0.178 1 1236 3,425 5, 6 ------ ------ Pr Watershed 1
8 SCS Runoff 5.058 1 729 17,811 ------ ------ ------ Pr Watershed 2a
9 Reservoir 0.767 1 770 8,296 8 234.09 9,988 Basin 2
10 SCS Runoff 2.842 1 729 9,953 ------ ------ ------ Pr Watershed 2b
11 Combine 2.842 1 729 18,249 9, 10 ------ ------ Pr Watershed 2
12 Combine 2.935 1 729 21,674 7, 11 ------ ------ Proposed Conditions
Analysis.gpw Return Period: 50 Year Tuesday, 01 / 14 / 2025
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Hydrograph type = SCS Runoff Peak discharge = 0.248 cfs
Storm frequency = 50 yrs Time to peak = 739 min
Time interval = 1 min Hyd. volume = 2,840 cuft
Drainage area = 1.420 ac Curve number = 36*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.30 min
Total precip. = 6.94 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.600 x 30) + (0.790 x 39) + (0.030 x 98)] / 1.420
69
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Q (cfs)
Time (min)
Ex Watershed 1
Hyd. No. 1 -- 50 Year
Hyd No. 1
Precipitation Report 70
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Storm Frequency = 50 yrs Time interval = 1 min
Total precip. = 6.9400 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 1 : Ex Watershed 1 - 50 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Hydrograph type = SCS Runoff Peak discharge = 1.395 cfs
Storm frequency = 50 yrs Time to peak = 742 min
Time interval = 1 min Hyd. volume = 10,279 cuft
Drainage area = 2.890 ac Curve number = 42*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 20.40 min
Total precip. = 6.94 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(1.760 x 30) + (0.500 x 77) + (0.540 x 39) + (0.090 x 98)] / 2.890
71
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Ex Watershed 2
Hyd. No. 2 -- 50 Year
Hyd No. 2
Precipitation Report 72
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Storm Frequency = 50 yrs Time interval = 1 min
Total precip. = 6.9400 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 2 : Ex Watershed 2 - 50 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 3
Existing Conditions
Hydrograph type = Combine Peak discharge = 1.637 cfs
Storm frequency = 50 yrs Time to peak = 741 min
Time interval = 1 min Hyd. volume = 13,119 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 4.310 ac
73
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
Q (cfs)
Time (min)
Existing Conditions
Hyd. No. 3 -- 50 Year
Hyd No. 3 Hyd No. 1 Hyd No. 2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Hydrograph type = SCS Runoff Peak discharge = 6.676 cfs
Storm frequency = 50 yrs Time to peak = 732 min
Time interval = 1 min Hyd. volume = 27,067 cuft
Drainage area = 1.920 ac Curve number = 73*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 14.50 min
Total precip. = 6.94 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.810 x 39) + (1.110 x 98)] / 1.920
74
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
7.00 7.00
Q (cfs)
Time (min)
Pr Watershed 1a
Hyd. No. 4 -- 50 Year
Hyd No. 4
Precipitation Report 75
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Storm Frequency = 50 yrs Time interval = 1 min
Total precip. = 6.9400 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 4 : Pr Watershed 1a - 50 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 5
Basin 1
Hydrograph type = Reservoir Peak discharge = 0.171 cfs
Storm frequency = 50 yrs Time to peak = 1241 min
Time interval = 1 min Hyd. volume = 2,894 cuft
Inflow hyd. No. = 4 - Pr Watershed 1a Max. Elevation = 234.02 ft
Reservoir name = Pond 1 Max. Storage = 24,421 cuft
Storage Indication method used.
76
0 180 360 540 720 900 1080 1260 1440 1620
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
7.00 7.00
Q (cfs)
Time (min)
Basin 1
Hyd. No. 5 -- 50 Year
Hyd No. 5 Hyd No. 4 Total storage used = 24,421 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Hydrograph type = SCS Runoff Peak discharge = 0.092 cfs
Storm frequency = 50 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 531 cuft
Drainage area = 0.190 ac Curve number = 39*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.94 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.190 x 39)] / 0.190
77
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.01 0.01
0.02 0.02
0.03 0.03
0.04 0.04
0.05 0.05
0.06 0.06
0.07 0.07
0.08 0.08
0.09 0.09
0.10 0.10
Q (cfs)
Time (min)
Pr Watershed 1b
Hyd. No. 6 -- 50 Year
Hyd No. 6
Precipitation Report 78
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Storm Frequency = 50 yrs Time interval = 1 min
Total precip. = 6.9400 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 6 : Pr Watershed 1b - 50 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 7
Pr Watershed 1
Hydrograph type = Combine Peak discharge = 0.178 cfs
Storm frequency = 50 yrs Time to peak = 1236 min
Time interval = 1 min Hyd. volume = 3,425 cuft
Inflow hyds. = 5, 6 Contrib. drain. area = 0.190 ac
79
0 180 360 540 720 900 1080 1260 1440 1620
Q (cfs)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Q (cfs)
Time (min)
Pr Watershed 1
Hyd. No. 7 -- 50 Year
Hyd No. 7 Hyd No. 5 Hyd No. 6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Hydrograph type = SCS Runoff Peak discharge = 5.058 cfs
Storm frequency = 50 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 17,811 cuft
Drainage area = 1.110 ac Curve number = 78*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.80 min
Total precip. = 6.94 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.370 x 39) + (0.740 x 98)] / 1.110
80
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (min)
Pr Watershed 2a
Hyd. No. 8 -- 50 Year
Hyd No. 8
Precipitation Report 81
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Storm Frequency = 50 yrs Time interval = 1 min
Total precip. = 6.9400 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 8 : Pr Watershed 2a - 50 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 9
Basin 2
Hydrograph type = Reservoir Peak discharge = 0.767 cfs
Storm frequency = 50 yrs Time to peak = 770 min
Time interval = 1 min Hyd. volume = 8,296 cuft
Inflow hyd. No. = 8 - Pr Watershed 2a Max. Elevation = 234.09 ft
Reservoir name = Pond 2 Max. Storage = 9,988 cuft
Storage Indication method used.
82
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (min)
Basin 2
Hyd. No. 9 -- 50 Year
Hyd No. 9 Hyd No. 8 Total storage used = 9,988 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Hydrograph type = SCS Runoff Peak discharge = 2.842 cfs
Storm frequency = 50 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 9,953 cuft
Drainage area = 0.960 ac Curve number = 63*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 6.94 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.120 x 30) + (0.040 x 77) + (0.230 x 39) + (0.280 x 80) + (0.290 x 77)] / 0.960
83
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Pr Watershed 2b
Hyd. No. 10 -- 50 Year
Hyd No. 10
Precipitation Report 84
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Storm Frequency = 50 yrs Time interval = 1 min
Total precip. = 6.9400 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 10 : Pr Watershed 2b - 50 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 11
Pr Watershed 2
Hydrograph type = Combine Peak discharge = 2.842 cfs
Storm frequency = 50 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 18,249 cuft
Inflow hyds. = 9, 10 Contrib. drain. area = 0.960 ac
85
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Pr Watershed 2
Hyd. No. 11 -- 50 Year
Hyd No. 11 Hyd No. 9 Hyd No. 10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 12
Proposed Conditions
Hydrograph type = Combine Peak discharge = 2.935 cfs
Storm frequency = 50 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 21,674 cuft
Inflow hyds. = 7, 11 Contrib. drain. area = 0.000 ac
86
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Proposed Conditions
Hyd. No. 12 -- 50 Year
Hyd No. 12 Hyd No. 7 Hyd No. 11
Hydrograph Summary Report
87
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 0.546 1 735 4,219 ------ ------ ------ Ex Watershed 1
2 SCS Runoff 2.205 1 739 14,068 ------ ------ ------ Ex Watershed 2
3 Combine 2.721 1 738 18,287 1, 2 ------ ------ Existing Conditions
4 SCS Runoff 7.884 1 732 32,045 ------ ------ ------ Pr Watershed 1a
5 Reservoir 0.347 1 964 7,872 4 234.04 24,679 Basin 1
6 SCS Runoff 0.169 1 728 753 ------ ------ ------ Pr Watershed 1b
7 Combine 0.361 1 967 8,625 5, 6 ------ ------ Pr Watershed 1
8 SCS Runoff 5.880 1 729 20,830 ------ ------ ------ Pr Watershed 2a
9 Reservoir 1.615 1 746 11,315 8 234.15 10,295 Basin 2
10 SCS Runoff 3.481 1 729 12,131 ------ ------ ------ Pr Watershed 2b
11 Combine 3.481 1 729 23,445 9, 10 ------ ------ Pr Watershed 2
12 Combine 3.648 1 729 32,070 7, 11 ------ ------ Proposed Conditions
Analysis.gpw Return Period: 100 Year Tuesday, 01 / 14 / 2025
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Hydrograph type = SCS Runoff Peak discharge = 0.546 cfs
Storm frequency = 100 yrs Time to peak = 735 min
Time interval = 1 min Hyd. volume = 4,219 cuft
Drainage area = 1.420 ac Curve number = 36*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 10.30 min
Total precip. = 7.76 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.600 x 30) + (0.790 x 39) + (0.030 x 98)] / 1.420
88
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.10 0.10
0.20 0.20
0.30 0.30
0.40 0.40
0.50 0.50
0.60 0.60
0.70 0.70
0.80 0.80
0.90 0.90
1.00 1.00
Q (cfs)
Time (min)
Ex Watershed 1
Hyd. No. 1 -- 100 Year
Hyd No. 1
Precipitation Report 89
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 1
Ex Watershed 1
Storm Frequency = 100 yrs Time interval = 1 min
Total precip. = 7.7600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 1 : Ex Watershed 1 - 100 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Hydrograph type = SCS Runoff Peak discharge = 2.205 cfs
Storm frequency = 100 yrs Time to peak = 739 min
Time interval = 1 min Hyd. volume = 14,068 cuft
Drainage area = 2.890 ac Curve number = 42*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 20.40 min
Total precip. = 7.76 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(1.760 x 30) + (0.500 x 77) + (0.540 x 39) + (0.090 x 98)] / 2.890
90
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Ex Watershed 2
Hyd. No. 2 -- 100 Year
Hyd No. 2
Precipitation Report 91
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 2
Ex Watershed 2
Storm Frequency = 100 yrs Time interval = 1 min
Total precip. = 7.7600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 2 : Ex Watershed 2 - 100 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 3
Existing Conditions
Hydrograph type = Combine Peak discharge = 2.721 cfs
Storm frequency = 100 yrs Time to peak = 738 min
Time interval = 1 min Hyd. volume = 18,287 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 4.310 ac
92
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Q (cfs)
Time (min)
Existing Conditions
Hyd. No. 3 -- 100 Year
Hyd No. 3 Hyd No. 1 Hyd No. 2
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Hydrograph type = SCS Runoff Peak discharge = 7.884 cfs
Storm frequency = 100 yrs Time to peak = 732 min
Time interval = 1 min Hyd. volume = 32,045 cuft
Drainage area = 1.920 ac Curve number = 73*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 14.50 min
Total precip. = 7.76 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.810 x 39) + (1.110 x 98)] / 1.920
93
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
Q (cfs)
Time (min)
Pr Watershed 1a
Hyd. No. 4 -- 100 Year
Hyd No. 4
Precipitation Report 94
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 4
Pr Watershed 1a
Storm Frequency = 100 yrs Time interval = 1 min
Total precip. = 7.7600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 4 : Pr Watershed 1a - 100 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 5
Basin 1
Hydrograph type = Reservoir Peak discharge = 0.347 cfs
Storm frequency = 100 yrs Time to peak = 964 min
Time interval = 1 min Hyd. volume = 7,872 cuft
Inflow hyd. No. = 4 - Pr Watershed 1a Max. Elevation = 234.04 ft
Reservoir name = Pond 1 Max. Storage = 24,679 cuft
Storage Indication method used.
95
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
2.00 2.00
4.00 4.00
6.00 6.00
8.00 8.00
Q (cfs)
Time (min)
Basin 1
Hyd. No. 5 -- 100 Year
Hyd No. 5 Hyd No. 4 Total storage used = 24,679 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Hydrograph type = SCS Runoff Peak discharge = 0.169 cfs
Storm frequency = 100 yrs Time to peak = 728 min
Time interval = 1 min Hyd. volume = 753 cuft
Drainage area = 0.190 ac Curve number = 39*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 7.76 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.190 x 39)] / 0.190
96
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Q (cfs)
Time (min)
Pr Watershed 1b
Hyd. No. 6 -- 100 Year
Hyd No. 6
Precipitation Report 97
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 6
Pr Watershed 1b
Storm Frequency = 100 yrs Time interval = 1 min
Total precip. = 7.7600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 6 : Pr Watershed 1b - 100 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 7
Pr Watershed 1
Hydrograph type = Combine Peak discharge = 0.361 cfs
Storm frequency = 100 yrs Time to peak = 967 min
Time interval = 1 min Hyd. volume = 8,625 cuft
Inflow hyds. = 5, 6 Contrib. drain. area = 0.190 ac
98
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Q (cfs)
Time (min)
Pr Watershed 1
Hyd. No. 7 -- 100 Year
Hyd No. 7 Hyd No. 5 Hyd No. 6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Hydrograph type = SCS Runoff Peak discharge = 5.880 cfs
Storm frequency = 100 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 20,830 cuft
Drainage area = 1.110 ac Curve number = 78*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.80 min
Total precip. = 7.76 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.370 x 39) + (0.740 x 98)] / 1.110
99
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (min)
Pr Watershed 2a
Hyd. No. 8 -- 100 Year
Hyd No. 8
Precipitation Report 100
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 8
Pr Watershed 2a
Storm Frequency = 100 yrs Time interval = 1 min
Total precip. = 7.7600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 8 : Pr Watershed 2a - 100 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 9
Basin 2
Hydrograph type = Reservoir Peak discharge = 1.615 cfs
Storm frequency = 100 yrs Time to peak = 746 min
Time interval = 1 min Hyd. volume = 11,315 cuft
Inflow hyd. No. = 8 - Pr Watershed 2a Max. Elevation = 234.15 ft
Reservoir name = Pond 2 Max. Storage = 10,295 cuft
Storage Indication method used.
101
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
5.00 5.00
6.00 6.00
Q (cfs)
Time (min)
Basin 2
Hyd. No. 9 -- 100 Year
Hyd No. 9 Hyd No. 8 Total storage used = 10,295 cuft
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Hydrograph type = SCS Runoff Peak discharge = 3.481 cfs
Storm frequency = 100 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 12,131 cuft
Drainage area = 0.960 ac Curve number = 63*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 10.00 min
Total precip. = 7.76 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cdsShape factor = 484
* Composite (Area/CN) = [(0.120 x 30) + (0.040 x 77) + (0.230 x 39) + (0.280 x 80) + (0.290 x 77)] / 0.960
102
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
Q (cfs)
Time (min)
Pr Watershed 2b
Hyd. No. 10 -- 100 Year
Hyd No. 10
Precipitation Report 103
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 10
Pr Watershed 2b
Storm Frequency = 100 yrs Time interval = 1 min
Total precip. = 7.7600 in Distribution = Custom
Storm duration = M:\NOAA Type D Distribution 1 min.cds
0 140 280 420 560 700 840 980 1120 1260 1400 1540
Precip (in)
0.00 0.00
0.05 0.05
0.10 0.10
0.15 0.15
0.20 0.20
0.25 0.25
0.30 0.30
0.35 0.35
0.40 0.40
0.45 0.45
0.50 0.50
Precip (in)
Time (min)Custom Design Storm -- M:\NOAA Type D Distribution 1 min.cds
Incremental Rainfall Precipitation
Hyd. No. 10 : Pr Watershed 2b - 100 Year
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 11
Pr Watershed 2
Hydrograph type = Combine Peak discharge = 3.481 cfs
Storm frequency = 100 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 23,445 cuft
Inflow hyds. = 9, 10 Contrib. drain. area = 0.960 ac
104
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
Q (cfs)
Time (min)
Pr Watershed 2
Hyd. No. 11 -- 100 Year
Hyd No. 11 Hyd No. 9 Hyd No. 10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Hyd. No. 12
Proposed Conditions
Hydrograph type = Combine Peak discharge = 3.648 cfs
Storm frequency = 100 yrs Time to peak = 729 min
Time interval = 1 min Hyd. volume = 32,070 cuft
Inflow hyds. = 7, 11 Contrib. drain. area = 0.000 ac
105
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Q (cfs)
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
4.00 4.00
Q (cfs)
Time (min)
Proposed Conditions
Hyd. No. 12 -- 100 Year
Hyd No. 12 Hyd No. 7 Hyd No. 11
Hydraflow Rainfall Report 106
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Tuesday, 01 / 14 / 2025
Return Intensity-Duration-Frequency Equation Coefficients (FHA)
Period
(Yrs) B D E (N/A)
1 0.0000 0.0000 0.0000 --------
2 21.8860 3.8000 0.6927 --------
3 0.0000 0.0000 0.0000 --------
5 0.0000 0.0000 0.0000 --------
10 30.7805 3.4000 0.6802 --------
25 37.8346 3.5000 0.6853 --------
50 43.4031 3.6000 0.6893 --------
100 48.2349 3.6000 0.6872 --------
File name: 7767F Intensity Values for Rational Method.IDF
Intensity = B / (Tc + D)^E
Return Intensity Values (in/hr)
Period(Yrs)5 min1015202530354045505560
1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
2 4.85 3.55 2.87 2.44 2.13 1.91 1.74 1.60 1.48 1.38 1.30 1.23
3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
10 7.24 5.27 4.25 3.60 3.16 2.83 2.57 2.37 2.20 2.06 1.94 1.83
25 8.73 6.36 5.12 4.35 3.81 3.41 3.10 2.85 2.65 2.47 2.33 2.20
50 9.85 7.18 5.79 4.91 4.30 3.85 3.50 3.22 2.99 2.79 2.62 2.48
100 10.99 8.02 6.47 5.49 4.81 4.31 3.92 3.60 3.34 3.13 2.94 2.78
Tc = time in minutes. Values may exceed 60.
Rainfall Precipitation Table (in)
00\7767F - Rand Whitney Stormwater Design\Studies-Calculations\Drainage\7767F Depth Values for SCS Method.pcp
Storm
Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
SCS 24-hour 0.00 3.45 0.00 0.00 5.12 6.16 6.94 7.76
SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Custom 0.00 3.45 0.00 0.00 5.12 6.16 6.94 7.76
CLA Engineers, Inc.
Civil · Structural · Survey
Appendix B
Rainfall Data
NOAA Atlas 14, Volume 10, Version 3
Location name: Uncasville, Connecticut, USA*
Latitude: 41.453°, Longitude: -72.1399°
Elevation: 240 ft**
* source: ESRI Maps** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Orlan Wilhite
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Duration Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 0.340
(0.265‑0.426)
0.406
(0.316‑0.509)
0.514
(0.399‑0.647)
0.604
(0.466‑0.763)
0.728
(0.544‑0.953)
0.821
(0.601‑1.09)
0.918
(0.654‑1.26)
1.03
(0.693‑1.44)
1.19
(0.770‑1.70)
1.32
(0.836‑1.93)
10-min 0.482
(0.375‑0.603)
0.576
(0.448‑0.721)
0.729
(0.566‑0.916)
0.856
(0.660‑1.08)
1.03
(0.771‑1.35)
1.16
(0.852‑1.55)
1.30
(0.926‑1.79)
1.46
(0.982‑2.03)
1.68
(1.09‑2.42)
1.87
(1.18‑2.73)
15-min 0.567
(0.442‑0.710)
0.677
(0.527‑0.849)
0.857
(0.665‑1.08)
1.01
(0.777‑1.27)
1.21
(0.907‑1.59)
1.37
(1.00‑1.82)
1.53
(1.09‑2.10)
1.72
(1.16‑2.39)
1.98
(1.28‑2.84)
2.20
(1.39‑3.21)
30-min 0.798
(0.622‑1.00)
0.953
(0.742‑1.20)
1.21
(0.937‑1.52)
1.42
(1.09‑1.79)
1.71
(1.28‑2.24)
1.92
(1.41‑2.56)
2.15
(1.53‑2.96)
2.41
(1.62‑3.36)
2.78
(1.80‑4.00)
3.09
(1.96‑4.51)
60-min 1.03
(0.802‑1.29)
1.23
(0.957‑1.54)
1.56
(1.21‑1.96)
1.83
(1.41‑2.31)
2.20
(1.64‑2.88)
2.48
(1.82‑3.31)
2.78
(1.98‑3.82)
3.11
(2.10‑4.34)
3.59
(2.33‑5.15)
3.98
(2.52‑5.81)
2-hr 1.35
(1.06‑1.68)
1.61
(1.27‑2.01)
2.04
(1.59‑2.54)
2.39
(1.86‑3.00)
2.88
(2.17‑3.74)
3.24
(2.39‑4.29)
3.63
(2.60‑4.96)
4.07
(2.76‑5.63)
4.73
(3.08‑6.72)
5.27
(3.35‑7.62)
3-hr 1.57
(1.24‑1.95)
1.87
(1.48‑2.32)
2.36
(1.86‑2.94)
2.77
(2.16‑3.46)
3.33
(2.52‑4.32)
3.75
(2.78‑4.94)
4.19
(3.02‑5.71)
4.71
(3.20‑6.48)
5.48
(3.57‑7.75)
6.12
(3.90‑8.79)
6-hr 2.00
(1.59‑2.46)
2.37
(1.88‑2.92)
2.99
(2.36‑3.69)
3.50
(2.75‑4.33)
4.20
(3.19‑5.39)
4.72
(3.52‑6.17)
5.27
(3.82‑7.12)
5.92
(4.04‑8.08)
6.88
(4.51‑9.64)
7.68
(4.91‑10.9)
12-hr 2.47
(1.98‑3.02)
2.93
(2.34‑3.58)
3.68
(2.93‑4.51)
4.30
(3.41‑5.30)
5.16
(3.95‑6.58)
5.80
(4.35‑7.53)
6.48
(4.72‑8.67)
7.27
(4.98‑9.83)
8.42
(5.54‑11.7)
9.38
(6.02‑13.2)
24-hr 2.90
(2.34‑3.52)
3.45
(2.78‑4.20)
4.36
(3.50‑5.31)
5.12
(4.08‑6.26)
6.16
(4.75‑7.80)
6.94
(5.24‑8.93)
7.76
(5.69‑10.3)
8.72
(6.01‑11.7)
10.1
(6.71‑14.0)
11.3
(7.31‑15.8)
2-day 3.25
(2.64‑3.91)
3.91
(3.18‑4.72)
5.00
(4.04‑6.04)
5.90
(4.74‑7.16)
7.14
(5.55‑8.99)
8.06
(6.14‑10.3)
9.06
(6.70‑12.0)
10.2
(7.09‑13.6)
12.0
(7.98‑16.4)
13.6
(8.77‑18.8)
3-day 3.52
(2.88‑4.23)
4.24
(3.46‑5.10)
5.42
(4.40‑6.53)
6.40
(5.16‑7.73)
7.74
(6.05‑9.71)
8.74
(6.68‑11.2)
9.82
(7.29‑12.9)
11.1
(7.71‑14.7)
13.1
(8.69‑17.7)
14.7
(9.55‑20.3)
4-day 3.78
(3.10‑4.53)
4.54
(3.72‑5.44)
5.78
(4.71‑6.94)
6.81
(5.51‑8.20)
8.22
(6.44‑10.3)
9.27
(7.11‑11.8)
10.4
(7.74‑13.7)
11.8
(8.18‑15.5)
13.8
(9.20‑18.7)
15.6
(10.1‑21.3)
7-day 4.52
(3.72‑5.37)
5.34
(4.40‑6.36)
6.70
(5.50‑8.00)
7.83
(6.38‑9.38)
9.38
(7.38‑11.6)
10.5
(8.10‑13.3)
11.8
(8.78‑15.3)
13.2
(9.24‑17.3)
15.4
(10.3‑20.6)
17.2
(11.2‑23.4)
10-day 5.24
(4.33‑6.21)
6.10
(5.05‑7.24)
7.53
(6.20‑8.95)
8.71
(7.12‑10.4)
10.3
(8.15‑12.7)
11.5
(8.90‑14.5)
12.8
(9.57‑16.5)
14.3
(10.0‑18.6)
16.5
(11.1‑22.0)
18.3
(12.0‑24.8)
20-day 7.45
(6.21‑8.76)
8.37
(6.98‑9.86)
9.89
(8.20‑11.7)
11.1
(9.19‑13.2)
12.9
(10.2‑15.7)
14.2
(11.0‑17.5)
15.5
(11.6‑19.6)
17.0
(12.0‑21.8)
18.9
(12.8‑24.9)
20.4
(13.4‑27.3)
30-day 9.29
(7.78‑10.9)
10.2
(8.58‑12.0)
11.8
(9.85‑13.9)
13.1
(10.9‑15.5)
14.9
(11.9‑18.0)
16.3
(12.6‑19.9)
17.7
(13.1‑22.0)
19.0
(13.5‑24.3)
20.7
(14.1‑27.2)
22.0
(14.5‑29.3)
45-day 11.6
(9.74‑13.5)
12.6
(10.6‑14.7)
14.2
(11.9‑16.6)
15.6
(13.0‑18.3)
17.5
(13.9‑20.9)
19.0
(14.7‑23.0)
20.4
(15.1‑25.1)
21.6
(15.4‑27.5)
23.2
(15.8‑30.2)
24.2
(15.9‑32.0)
60-day 13.5
(11.4‑15.7)
14.5
(12.2‑16.9)
16.2
(13.6‑18.9)
17.7
(14.7‑20.7)
19.6
(15.7‑23.4)
21.2
(16.5‑25.6)
22.7
(16.8‑27.8)
23.9
(17.1‑30.3)
25.3
(17.3‑32.9)
26.2
(17.4‑34.5)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequencyestimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates atupper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
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Large scale map
Large scale aerial
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National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: HDSC.Questions@noaa.gov
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NOAA Atlas 14, Volume 10, Version 3
Location name: Uncasville, Connecticut, USA*
Latitude: 41.453°, Longitude: -72.1399°
Elevation: 240 ft**
* source: ESRI Maps** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Orlan Wilhite
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Duration Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 4.08
(3.18‑5.11)
4.87
(3.79‑6.11)
6.17
(4.79‑7.76)
7.25
(5.59‑9.16)
8.74
(6.53‑11.4)
9.85
(7.21‑13.1)
11.0
(7.85‑15.1)
12.3
(8.32‑17.2)
14.3
(9.24‑20.5)
15.9
(10.0‑23.1)
10-min 2.89
(2.25‑3.62)
3.46
(2.69‑4.33)
4.37
(3.40‑5.50)
5.14
(3.96‑6.49)
6.19
(4.63‑8.10)
6.98
(5.11‑9.29)
7.81
(5.56‑10.7)
8.75
(5.89‑12.2)
10.1
(6.55‑14.5)
11.2
(7.10‑16.4)
15-min 2.27
(1.77‑2.84)
2.71
(2.11‑3.40)
3.43
(2.66‑4.31)
4.03
(3.11‑5.08)
4.85
(3.63‑6.35)
5.47
(4.01‑7.29)
6.12
(4.36‑8.42)
6.86
(4.62‑9.58)
7.93
(5.14‑11.4)
8.80
(5.57‑12.8)
30-min 1.60
(1.24‑2.00)
1.91
(1.48‑2.39)
2.41
(1.87‑3.03)
2.83
(2.19‑3.58)
3.41
(2.55‑4.47)
3.85
(2.82‑5.13)
4.31
(3.06‑5.92)
4.83
(3.25‑6.73)
5.57
(3.61‑7.99)
6.18
(3.91‑9.02)
60-min 1.03
(0.802‑1.29)
1.23
(0.957‑1.54)
1.56
(1.21‑1.96)
1.83
(1.41‑2.31)
2.20
(1.64‑2.88)
2.48
(1.82‑3.31)
2.78
(1.98‑3.82)
3.11
(2.10‑4.34)
3.59
(2.33‑5.15)
3.98
(2.52‑5.81)
2-hr 0.677
(0.531‑0.842)
0.807
(0.633‑1.00)
1.02
(0.797‑1.27)
1.20
(0.930‑1.50)
1.44
(1.08‑1.87)
1.62
(1.20‑2.15)
1.81
(1.30‑2.48)
2.04
(1.38‑2.82)
2.36
(1.54‑3.36)
2.64
(1.67‑3.81)
3-hr 0.523
(0.413‑0.649)
0.623
(0.491‑0.773)
0.787
(0.617‑0.978)
0.922
(0.719‑1.15)
1.11
(0.838‑1.44)
1.25
(0.924‑1.65)
1.40
(1.00‑1.90)
1.57
(1.06‑2.16)
1.82
(1.19‑2.58)
2.04
(1.30‑2.93)
6-hr 0.334
(0.265‑0.410)
0.396
(0.314‑0.488)
0.498
(0.394‑0.615)
0.583
(0.458‑0.723)
0.700
(0.533‑0.900)
0.787
(0.587‑1.03)
0.880
(0.637‑1.19)
0.988
(0.674‑1.35)
1.15
(0.752‑1.61)
1.28
(0.820‑1.83)
12-hr 0.205
(0.164‑0.250)
0.243
(0.194‑0.297)
0.305
(0.243‑0.374)
0.357
(0.282‑0.439)
0.428
(0.328‑0.546)
0.481
(0.361‑0.624)
0.537
(0.391‑0.719)
0.603
(0.413‑0.815)
0.698
(0.459‑0.970)
0.778
(0.499‑1.10)
24-hr 0.120
(0.097‑0.146)
0.143
(0.115‑0.174)
0.181
(0.145‑0.221)
0.213
(0.170‑0.260)
0.256
(0.197‑0.325)
0.288
(0.218‑0.372)
0.323
(0.237‑0.429)
0.363
(0.250‑0.487)
0.422
(0.279‑0.582)
0.472
(0.304‑0.660)
2-day 0.067
(0.054‑0.081)
0.081
(0.066‑0.098)
0.104
(0.084‑0.125)
0.122
(0.098‑0.149)
0.148
(0.115‑0.187)
0.167
(0.127‑0.215)
0.188
(0.139‑0.249)
0.213
(0.147‑0.283)
0.250
(0.166‑0.341)
0.282
(0.182‑0.390)
3-day 0.048
(0.039‑0.058)
0.058
(0.048‑0.070)
0.075
(0.061‑0.090)
0.088
(0.071‑0.107)
0.107
(0.083‑0.134)
0.121
(0.092‑0.154)
0.136
(0.101‑0.179)
0.154
(0.107‑0.204)
0.181
(0.120‑0.246)
0.204
(0.132‑0.281)
4-day 0.039
(0.032‑0.047)
0.047
(0.038‑0.056)
0.060
(0.049‑0.072)
0.070
(0.057‑0.085)
0.085
(0.067‑0.107)
0.096
(0.074‑0.122)
0.108
(0.080‑0.142)
0.122
(0.085‑0.161)
0.143
(0.095‑0.194)
0.162
(0.105‑0.222)
7-day 0.026
(0.022‑0.031)
0.031
(0.026‑0.037)
0.039
(0.032‑0.047)
0.046
(0.037‑0.055)
0.055
(0.043‑0.069)
0.062
(0.048‑0.078)
0.070
(0.052‑0.090)
0.078
(0.054‑0.102)
0.091
(0.061‑0.122)
0.102
(0.066‑0.139)
10-day 0.021
(0.018‑0.025)
0.025
(0.021‑0.030)
0.031
(0.025‑0.037)
0.036
(0.029‑0.043)
0.043
(0.033‑0.053)
0.048
(0.037‑0.060)
0.053
(0.039‑0.068)
0.059
(0.041‑0.077)
0.068
(0.046‑0.091)
0.076
(0.049‑0.103)
20-day 0.015
(0.012‑0.018)
0.017
(0.014‑0.020)
0.020
(0.017‑0.024)
0.023
(0.019‑0.027)
0.026
(0.021‑0.032)
0.029
(0.022‑0.036)
0.032
(0.024‑0.040)
0.035
(0.024‑0.045)
0.039
(0.026‑0.051)
0.042
(0.027‑0.056)
30-day 0.012
(0.010‑0.015)
0.014
(0.011‑0.016)
0.016
(0.013‑0.019)
0.018
(0.015‑0.021)
0.020
(0.016‑0.024)
0.022
(0.017‑0.027)
0.024
(0.018‑0.030)
0.026
(0.018‑0.033)
0.028
(0.019‑0.037)
0.030
(0.020‑0.040)
45-day 0.010
(0.009‑0.012)
0.011
(0.009‑0.013)
0.013
(0.011‑0.015)
0.014
(0.012‑0.016)
0.016
(0.012‑0.019)
0.017
(0.013‑0.021)
0.018
(0.013‑0.023)
0.020
(0.014‑0.025)
0.021
(0.014‑0.027)
0.022
(0.014‑0.029)
60-day 0.009
(0.007‑0.010)
0.010
(0.008‑0.011)
0.011
(0.009‑0.013)
0.012
(0.010‑0.014)
0.013
(0.010‑0.016)
0.014
(0.011‑0.017)
0.015
(0.011‑0.019)
0.016
(0.011‑0.021)
0.017
(0.011‑0.022)
0.018
(0.012‑0.023)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (fora given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are notchecked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
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CLA Engineers, Inc.
Civil · Structural · Survey
Appendix D
StreamStats Report
StreamStats Report
Collapse All
Basin Characteristics
Parameter
Code Parameter Description Value Unit
DRNAREA Area that drains to a point on a stream 9.66 square
miles
I24H100Y Maximum 24-hour precipitation that occurs on average once in 100 years 7.79 inches
I24H10Y Maximum 24-hour precipitation that occurs on average once in 10 years 5.07 inches
I24H200Y Maximum 24-hour precipitation that occurs on average once in 200 years 8.89 inches
I24H25Y Maximum 24-hour precipitation that occurs on average once in 25 years 6.15 inches
I24H2Y Maximum 24-hour precipitation that occurs on average once in 2 years - Equivalent to
precipitation intensity index
3.16 inches
I24H500Y Maximum 24-hour precipitation that occurs on average once in 500 years 10.34 inches
I24H50Y Maximum 24-hour precipitation that occurs on average once in 50 years 6.97 inches
I24H5Y Maximum 24-hour precipitation that occurs on average once in 5 years 4.25 inches
SSURGOCCDD Percentage of area with hydrologic soil types C, D, or C/D from SSURGO 0.3108 percent
Region ID:CT
Workspace ID:CT20241205180712767000
Clicked Point (Latitude, Longitude):41.45263, -72.13696
Time:2024-12-05 13:07:40 -0500
12/5/24, 1:09 PM StreamStats
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Peak-Flow Statistics
Peak-Flow Statistics Parameters [Statewide DA only SIR 2020 5054]
Parameter Code Parameter Name Value Units Min Limit Max Limit
DRNAREA Drainage Area 9.66 square miles 0.69 325
Peak-Flow Statistics Parameters [Statewide Multiparameter SIR 2020 5054]
Parameter Code Parameter Name Value Units Min Limit Max Limit
DRNAREA Drainage Area 9.66 square miles 0.69 325
I24H2Y 24 Hour 2 Year Precipitation 3.16 inches 2.77 3.32
SSURGOCCDD Percent soil type C or D from SSURGO 0.3108 percent 0.118 0.945
I24H5Y 24 Hour 5 Year Precipitation 4.25 inches 4 4.7
I24H10Y 24 Hour 10 Year Precipitation 5.07 inches 4.86 5.79
I24H25Y 24 Hour 25 Year Precipitation 6.15 inches 5.99 7.22
I24H50Y 24 Hour 50 Year Precipitation 6.97 inches 6.81 8.3
I24H100Y 24 Hour 100 Year Precipitation 7.79 inches 7.62 9.38
I24H200Y 24 Hour 200 YearPrecipitation 8.89 inches 8.7 11.22
I24H500Y 24 Hour 500 Year Precipitation 10.34 inches 10.1 13.64
Peak-Flow Statistics Flow Report [Statewide DA only SIR 2020 5054]
PIL: Lower 90% Prediction Interval, PIU: Upper 90% Prediction Interval, ASEp: Average Standard Error of Prediction, SE: Standard
Error, PC: Percent Correct, RMSE: Root Mean Squared Error, PseudoR^2: Pseudo R Squared (other -- see report)
Statistic Value Unit ASEp
Drainage Area Only 50-percent AEP flood 374 ft^3/s 35
Drainage Area Only 20-percent AEP flood 645 ft^3/s 35
Drainage Area Only 10-percent AEP flood 870 ft^3/s 36.3
Drainage Area Only 4-percent AEP flood 1210 ft^3/s 37.8
Drainage Area Only 2-percent AEP flood 1490 ft^3/s 39.8
Drainage Area Only 1-percent AEP flood 1810 ft^3/s 42.4
Drainage Area Only 0.5-percent AEP flood 2180 ft^3/s 44.4
Drainage Area Only 0.2-percent AEP flood 2720 ft^3/s 48
Peak-Flow Statistics Flow Report [Statewide Multiparameter SIR 2020 5054]
PIL: Lower 90% Prediction Interval, PIU: Upper 90% Prediction Interval, ASEp: Average Standard Error of Prediction, SE: Standard
Error, PC: Percent Correct, RMSE: Root Mean Squared Error, PseudoR^2: Pseudo R Squared (other -- see report)
Statistic Value Unit PIL PIU ASEp
50-percent AEP flood 326 ft^3/s 80 1330 26.5
20-percent AEP flood 488 ft^3/s 109 2190 26.3
10-percent AEP flood 608 ft^3/s 125 2950 28.4
4-percent AEP flood 805 ft^3/s 150 4320 31.5
2-percent AEP flood 978 ft^3/s 166 5760 34.3
1-percent AEP flood 1170 ft^3/s 181 7580 37.1
0.5-percent AEP flood 1380 ft^3/s 241 7890 40.6
12/5/24, 1:09 PM StreamStats
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Statistic Value Unit PIL PIU ASEp
0.2-percent AEP flood 1730 ft^3/s 323 9270 45
Peak-Flow Statistics Flow Report [Area-Averaged]
PIL: Lower 90% Prediction Interval, PIU: Upper 90% Prediction Interval, ASEp: Average Standard Error of Prediction, SE: Standard
Error, PC: Percent Correct, RMSE: Root Mean Squared Error, PseudoR^2: Pseudo R Squared (other -- see report)
Statistic Value Unit ASEp
Drainage Area Only 50-percent AEP flood 374 ft^3/s 35
Drainage Area Only 20-percent AEP flood 645 ft^3/s 35
Drainage Area Only 10-percent AEP flood 870 ft^3/s 36.3
Drainage Area Only 4-percent AEP flood 1210 ft^3/s 37.8
Drainage Area Only 2-percent AEP flood 1490 ft^3/s 39.8
Drainage Area Only 1-percent AEP flood 1810 ft^3/s 42.4
Drainage Area Only 0.5-percent AEP flood 2180 ft^3/s 44.4
Drainage Area Only 0.2-percent AEP flood 2720 ft^3/s 48
50-percent AEP flood 326 ft^3/s 80 1330 26.5
20-percent AEP flood 488 ft^3/s 109 2190 26.3
10-percent AEP flood 608 ft^3/s 125 2950 28.4
4-percent AEP flood 805 ft^3/s 150 4320 31.5
2-percent AEP flood 978 ft^3/s 166 5760 34.3
1-percent AEP flood 1170 ft^3/s 181 7580 37.1
0.5-percent AEP flood 1380 ft^3/s 241 7890 40.6
0.2-percent AEP flood 1730 ft^3/s 323 9270 45
Peak-Flow Statistics Citations
Ahearn, E.A., and Hodgkins, G.A.,2020, Estimating flood magnitude and frequency on streams and rivers in Connecticut, based
on data through water year 2015: U.S. Geological Survey Scientific Investigations Report 2020–5054, 42 p.
(https://doi.org/10.3133/sir20205054)
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