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HomeMy WebLinkAbout25IWC7-Silver Falls Rd - Application Binder CLA Engineers, Inc. Civil · Structural · Survey Application Material Proposed Subdivision Map 001- Block 007- Lot 00A Silver Falls Road Montville, Connecticut Table of Sections: 1. Subdivision Application 2. Inland Wetland Application 3. Soil Scientist Report / Narrative 4. DEEP Reporting Form 5. USGS Map 6. Firmette 7. List of Adjacent Property Owners 8. Drainage Report CLA Engineers, Inc. Civil · Structural · Survey Section 1. Subdivision Application CLA Engineers, Inc. Civil · Structural · Survey Section 2. Inland Wetland Application CLA Engineers, Inc. Civil · Structural · Survey Section 3. Soil Scientist Report / Narrative April 7, 2025 Town of Montville Inland Wetlands Commission Attn: Douglas K. Brush, Chair Montville Town Hall 310 Norwich-New London Tpke Uncasville, CT 06382 Re: Town of Montville Lot 00A Silver Falls Rd Montville, CT CLA #7885 Dear Mr. Brush: On behalf of the applicant, CLA Engineers has performed a delineation and functional evaluation of the inland wetlands at the referenced site and assessed the site to provide a basis for determining the potential for impacts. The inland wetland boundary was delineated by Robert Russo CSS between June and November 2024. The wetland boundary and proposed development are shown on the plans prepared by CLA Engineers dated December 5, 2024. These data were augmented with additional online information from CTDEEP, USFWS, USGS, and the Town of Montville. Site Setting The site is a 19.5-acre parcel located on the eastern side of Silver Falls Rd south of 27 Silver Falls Rd. The parcel abuts the Town of Waterford and is currently undeveloped. The majority of the parcel is forested and there are six (6) unique wetland areas on the property, five of which appear to have some degree of groundwater or surface connectivity. Only one on-site wetland area (defined on plans as Wetland 101) will be disturbed by the proposed development. Therefore, this wetland impact letter and associated function and value analysis focuses only on Wetland 101. The entire project area is within the Latimer Brook subregional drainage basin (2202). The surrounding neighborhood is zoned residential (R-60) per most recent update of the Town of Montville Zoning Map and consists of low- to medium-density single family residential lots, many of which are developed. Soils The upland and wetland soils mapped on the property by NRCS (USGS) are listed in the table below. Additional descriptive details are provided in Appendix A. CLA Engineers, Inc. Civil Structural Survey 317 MAIN STREET NORWICH, CT 06360 (860) 886-1966 (860) 886-9165 FAX Table 1 - Soil Types and Properties at the Silver Falls Rd Site Soil Series Parent Material Drainage Class Texture/Characteristics Ridgebury, Leicester, and Whitman (3)* Coarse-loamy lodgment till Poorly drained to very poorly drained Sandy loam Paxton and Montauk (85) Coarse-loamy lodgment till Well drained Fine sandy loam Raypol (12)* Coarse-loamy eolian deposits Poorly drained Silt loam Woodbridge (46-47) Coarse-loamy lodgment till Moderately well drained Fine sandy loam Haven (703) Coarse-loamy eolian deposits Well drained Silt loam *Hydric (wetland) soil type One wetland soil unit mapped on this site consists of Ridgebury, Leicester, and Whitman soils. The Ridgebury series consists of very deep, somewhat poorly and poorly drained soils formed in lodgment till derived mainly from granite, gneiss and/or schist. They are commonly shallow to a densic contact. They are nearly level to gently sloping soils in depressions in uplands. They also occur in drainageways in uplands, in toeslope positions of hills, drumlins, and ground moraines, and in till plains. The Leicester series consists of very deep, poorly drained soils formed in coarse-loamy till. They are nearly level or gently sloping soils in drainageways and low-lying positions on hills. The Whitman series consists of very deep, very poorly drained soils formed in lodgment till derived mainly from granite, gneiss, and schist. They are shallow to a densic contact. Another wetland soil unit mapped on this site is comprised of Raypol silt loam. The Raypol series consists of very deep, poorly drained soils formed in loamy over sandy and gravelly outwash. They are nearly level to gently sloping soils in shallow drainageways and low-lying positions on terraces and plains. The upland soil units on this site are Paxton and Montauk fine sandy loams, Woodbridge fine sandy loam, and Haven silt loam. The Paxton series consists of well drained loamy soils formed in lodgment till. The soils are very deep to bedrock and moderately deep to a densic contact. They are nearly level to steep soils on hills, drumlins, till plains, and ground moraines. The Montauk series consists of well drained soils formed in lodgment or flow till derived primarily from granitic materials with lesser amounts of gneiss and schist. The soils are very deep to bedrock and moderately deep to a densic contact. These soils are on upland hills and moraines. The Woodbridge series consists of moderately well drained loamy soils formed in lodgment till. They are very deep to bedrock and moderately deep to a densic contact. They are nearly level to moderately steep soils on hills, drumlins, till plains, and ground moraines. The Haven series consists of very deep, well drained soils formed in loamy over sandy and gravelly outwash. They are nearly level through moderately sloping soils on outwash plains, valley trains, terraces, and water-sorted moraine deposits. Wetland Characteristics Classification While the National Wetlands Inventory (NWI https ://fwsprimary.wim.usgs.gov/ wetlands/apps/wetlands-mapper/) does not identify the wetland, CLA determined the onsite wetland to be a 43,300 square foot palustrine forested wetland (PFO1E) and palustrine emergent wetland (PEM1E) based on field investigation and GIS site review. The description of that classification is provided below. Classification code: PFO1E System Palustrine (P): The Palustrine System includes all nontidal wetlands dominated by trees, shrubs, persistent emergents, emergent mosses or lichens, and all such wetlands that occur in tidal areas where salinity due to ocean-derived salts is below 0.5 ppt. It also includes wetlands lacking such vegetation, but with all of the following four characteristics: (1) area less than 8 ha (20 acres); (2) active wave-formed or bedrock shoreline features lacking; (3) water depth in the deepest part of basin less than 2.5 m (8.2 ft) at low water; and (4) salinity due to ocean-derived salts less than 0.5 ppt. Class Forested (FO): Characterized by woody vegetation that is 6 m tall or taller. Subclass Persistent (1): Dominated by species that normally remain standing at least until the beginning of the next growing season. This subclass is found only in the Estuarine and Palustrine systems. Water Regime Seasonally Flooded/Saturated (E): Surface water is present for extended periods (generally for more than a month) during the growing season, but is absent by the end of the season in most years. When surface water is absent, the substrate typically remains saturated at or near the surface. Classification code: PEM1E System Palustrine (P): The Palustrine System includes all nontidal wetlands dominated by trees, shrubs, persistent emergents, emergent mosses or lichens, and all such wetlands that occur in tidal areas where salinity due to ocean-derived salts is below 0.5 ppt. It also includes wetlands lacking such vegetation, but with all of the following four characteristics: (1) area less than 8 ha (20 acres); (2) active wave-formed or bedrock shoreline features lacking; (3) water depth in the deepest part of basin less than 2.5 m (8.2 ft) at low water; and (4) salinity due to ocean-derived salts less than 0.5 ppt. Class Emergent (EM): Characterized by erect, rooted, herbaceous hydrophytes, excluding mosses and lichens. This vegetation is present for most of the growing season in most years. These wetlands are usually dominated by perennial plants. Subclass Persistent (1): Dominated by species that normally remain standing at least until the beginning of the next growing season. This subclass is found only in the Estuarine and Palustrine systems. Water Regime Seasonally Flooded/Saturated (E): Surface water is present for extended periods (generally for more than a month) during the growing season, but is absent by the end of the season in most years. When surface water is absent, the substrate typically remains saturated at or near the surface. Wetland hydrology The onsite wetland consists largely of a palustrine forested wetland area with likely groundwater connectivity to other wetlands and water bodies, most notably Silver Falls Pond across the street. Since the proposed development is not within 100 feet of any wetland besides Wetland 101, the below functional assessment focuses only on Wetland 101. The wetland is densely vegetated and appears healthy with high organic matter content in the soil. Various strata of vegetation exist within and around the wetland (trees, shrubs, emergent, mosses, etc.), evidencing relatively high plant biodiversity in the wetland. The wetland sits high in the drainage basin and appears to have groundwater connectivity to the other wetlands on site as well as Latimer Brook, a tributary to the Niantic River. The wetland is saturated but does not contain sufficient ponded water to support finfish or shellfish habitat. Additionally, a FEMA-designated floodplain contains much of Wetland 101 and the surrounding upland. The FEMA flood map for this site is included in Appendix B. Factors important to functional assessment The following observations are important to the functional assessment and are listed here to provide context to the later discussion of functions and values. 1. Connecticut protected species are known to be present on the site per the June 2024 update of the CTDEEP NDDB. 2. The wetland has two dominant classes (PFO1E and PEM1E). 3. The local zoning is residential (R-60) per the Town GIS, and the surrounding parcels appear to be used for single-family residences. 4. The wetland has melt-out till soils along its edge and lodgement till soils within per available online mapping. Detailed soil mapping from the U.S. Web Soil Survey are included within Appendix A. 5. The wetland is a part of a larger watercourse system (Niantic River system). 6. The wetland appears to be healthy and densely vegetated, and most of its edges are surrounded by at least 100 feet of undeveloped buffer area. Principal functions The functional assessment was conducted using the USCAE Highway Methodology (https://www.nae.usace.army.mil/Portals/74/docs/regulatory/Forms/HighwaySupplement6Apr20 15.pdf). The assessment is included as Appendix C and it revealed that the wetland has the following principal functions: 1. Groundwater recharge and discharge: this wetland has a variable water level and lacks a permanent outlet, indicating that it feeds the groundwater system. 2. Nutrient removal: the wetland is rich in organic material, which is highly capable of removing excess nutrients from agricultural operations and roads upland and upstream of the wetland. 3. Wildlife habitat: overland access from the wetland is possible to six (6) unique classes of wetland as well as upland areas. 4. Endangered species habitat: The Connecticut Natural Diversity Data Base (CTNDDB) has identified the wetland area as an area of concern for endangered species. Proposed Development As shown on the project plans, the following activities are planned in the wetland for a total of approximately 4,590 square feet of disturbance: 1. Construction and grading of a common driveway across the property from Silver Falls Rd to the four unique housing lots in the subdivision. Contractors will utilize typical excavators, loaders, rollers, and dump trucks for the construction of the driveway. 2. Construction of a 15” culvert beneath the driveway to promote connectivity in the wetland on both sides of the driveway. 3. Construction of a 70’ by 45’ stormwater quality basin within the upland review area (outside of the wetland) to manage runoff from the driveway area. 4. Implementation of erosion and sedimentation control measures in and around the project area including silt fence, grassed swale, anti-tracking pad, and hay bale barrier. Table: total wetland impacts from the proposed driveway construction Area in square U.S. feet Area in acres Permanent area impacted 4590 +/- 0.10 +/- Temporary area impacted 0 0 Potential for Impacts The proposed activities outlined above may impact the wetland’s principal functions in the following ways: 1. Groundwater recharge and discharge: because the stormwater basin is sized to accommodate for the changes in drainage due to the driveway, CLA does not anticipate any changes to the wetland’s ability to perform this function. 2. Nutrient removal: the proposed driveway could increase the overall nutrient load into the wetland. However, if proper erosion and sedimentation controls are implemented during and after construction as indicated on plans, CLA does not predict significant impacts to this functionality. 3. Wildlife habitat: because the area of the driveway is small relative to the wetland and quite narrow, we do not expect this project to impact wildlife habitat via fragmentation or other means. For instance, bats can easily travel across roadways with low or moderate traffic flow where the distance from one tree canopy to the other is less than 20 meters1. Because the proposed project is a private driveway only 14 feet in width, we do not expect to see any habitat fragmentation or collision risk for bat species. 4. Endangered species habitat: see “Wildlife Habitat” above. Narrative Describing the Activities to Take place on the property. This section is responsive to the Town of Montville Inland Wetlands Checklist, page 2 Item 3, Narrative. Alternatives considered This site is a developable parcel of land that has wetland along the entire road frontage as shown on the project plans. As such, the access driveway was located so as to minimize the total area of wetland disturbance by crossing the wetlands at the narrowest point. Description of the activity including location and square footage of disturbance. The overall all project consists of a 4-lot residential subdivision to be accessed from Sliver Spring Rd in Montville. The proposed development includes on site driveways, septic systems, wells, rain gardens and a stormwater treatment basin. The regulated activity includes construction of a residential driveway and a stormwater management basin within the upland review zone. More specifically, there will be a loss of approximately 4590 square feet of forested wetland in two separate locations within the first 400 feet of the intersection with Silver Falls Rd. The construction will include a15 inch diameter culvert at the first crossing location in order to provide connectivity to the upslope wetland and to protect the driveway. This work will be done in only after meeting with town staff and installation of the proper erosion and sediment control measures. The work will be performed with excavators, bulldozers and dump trucks. What type of erosion and sediment control will be used? As shown on the site plan, the following best management practices will be employed: 1. An anti-tracking pad at the construction entrance. 2. A rip rap swale along the edge of the driveway 3. Silt fence along the limits of disturbance 4. De-watering, if needed, as shown on the dewatering detail on the site plans. If machinery will be used or if work will be done by hand. Machinery will be used and it will include typical heavy construction machines such as excavators, bulldozers, and dump trucks. Identify the sub-drainage basin where the proposed activity will occur. The sub-drainage basin is number 2202. Summary CLA has designed the wetland crossing to occur at the narrowest available location thus providing for minimal loss of wetland habitat and function. If proper erosion and sedimentation controls are installed according to the site plans, we do not anticipate the proposed development will have any significant impact on the four principal functions of the onsite forested wetland. Sincerely, Robert C. Russo Soil and Wetland Scientist CLA Engineers, Norwich, CT Appendix A: Soil Map Adapted from Web Soil Survey, U.S. Geological Survey, U.S. Department of Agriculture Soil Map—State of Connecticut, Eastern Part (7885 Silver Falls Subdivision) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/2/2024 Page 1 of 3458810045882004588300458840045885004588600458810045882004588300458840045885004588600732400732500732600732700732800732900733000733100733200733300 732400 732500 732600 732700 732800 732900 733000 733100 733200 733300 41° 24' 57'' N 72° 13' 10'' W41° 24' 57'' N72° 12' 27'' W41° 24' 36'' N 72° 13' 10'' W41° 24' 36'' N 72° 12' 27'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 200 400 800 1200 Feet 0 50 100 200 300 Meters Map Scale: 1:4,630 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. Soil Map—State of Connecticut, Eastern Part (7885 Silver Falls Subdivision) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/2/2024 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3 Ridgebury, Leicester, and Whitman soils, 0 to 8 percent slopes, extremely stony 4.6 12.4% 12 Raypol silt loam, 0 to 3 percent slopes 2.3 6.1% 29B Agawam fine sandy loam, 3 to 8 percent slopes 0.8 2.2% 38C Hinckley loamy sand, 3 to 15 percent slopes 0.1 0.3% 46B Woodbridge fine sandy loam, 0 to 8 percent slopes, very stony 6.1 16.5% 47C Woodbridge fine sandy loam, 3 to 15 percent slopes, extremely stony 3.8 10.4% 75E Hollis-Chatfield-Rock outcrop complex, 15 to 45 percent slopes 0.1 0.2% 85B Paxton and Montauk fine sandy loams, 3 to 8 percent slopes, very stony 7.1 19.2% 85C Paxton and Montauk fine sandy loams, 8 to 15 percent slopes, very stony 7.3 19.8% 703B Haven silt loam, 3 to 8 percent slopes 3.2 8.8% W Water 1.5 4.1% Totals for Area of Interest 36.9 100.0% Soil Map—State of Connecticut, Eastern Part 7885 Silver Falls Subdivision Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/2/2024 Page 3 of 3 Appendix B: FEMA Firmette Map National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOODHAZARD AREAS Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or Depth Zone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood Hazard Zone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below.The basemap shown complies with FEMA's basemapaccuracy standards The flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 11/19/2024 at 4:51 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximatepoint selected by the user and does not representan authoritative property location. 1:6,000 72°13'20"W 41°25'7"N 72°12'42"W 41°24'40"N Basemap Imagery Source: USGS National Map 2023 Appendix C: Army Corps Wetland Assessment Sheet CLA Engineers, Inc. Civil · Structural · Survey Section 4. DEEP Reporting Form CLA Engineers, Inc. Civil · Structural · Survey Section 5. USGS Map CLA Engineers, Inc. Civil · Structural · Survey Section 6. Firmette National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOODHAZARD AREAS Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or Depth Zone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood Hazard Zone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below.The basemap shown complies with FEMA's basemapaccuracy standards The flood hazard information is derived directly from theauthoritative NFHL web services provided by FEMA. This mapwas exported on 11/19/2024 at 4:51 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximatepoint selected by the user and does not representan authoritative property location. 1:6,000 72°13'20"W 41°25'7"N 72°12'42"W 41°24'40"N Basemap Imagery Source: USGS National Map 2023 CLA Engineers, Inc. Civil · Structural · Survey Section 7. List of Adjacent Property Owners Adjacent Property Owner to Map 001/Block 007/Lot 00A Owner Location Mailing Address Mailing City Mailin Mailing Zip PALMER MICHAEL A 45 SILVER FALLS RD 45 SILVER FALLS RD OAKDALE CT 063701824 GJERGJAJ DANIELA SILVER FALLS RD 301 CHESTERFIELD RD EAST LYME CT 063331003 MACKAY JEFFREY R & JAMIE R 27 SILVER FALLS RD 27 SILVER FALLS RD OAKDALE CT 06370 HARVEY-BLAGDEN ELFRIEDA ELEANOR 15 SILVER FALLS RD 15 SILVER FALLS RD OAKDALE CT 063701824 STEARNS BRIAN J 230 BUTLERTOWN RD 230 BUTLERTOWN RD OAKDALE CT 06370 SKINNER CARMEN H 11 SILVER FALLS RD 11 SILVER FALLS RD OAKDALE CT 06370 MONTVILLE STAGING LLC 252 BUTLERTOWN RD 121 MEMORIAL DR SPRINGFIELD MA 01104 FIRLIK JOSEPH 225 BUTLERTOWN ROAD 34 ROGERS HILL ROAD WATERFORD CT 06385 GOLDEN TRAILS LLC 83 PEMBER ROAD 301 CHESTERFIELD ROAD EAST LYME CT 06333 WATERFORD LAND TRUST INC 55 PEMBER ROAD PO BOX 926 WATERFORD CT 06385 CYR VICTORIA & PALMER MICHAEL 18 SILVER FALLS RD 18 SILVER FALLS RD OAKDALE CT 063701823 BOSKA MARILYN L/U & BOSKA ROBERT W L/U&40 SILVER FALLS RD 45 SILVER FALLS RD OAKDALE CT 063701824 PRZYBYL LORI S B L/U & PALMER MICHAEL A CLA Engineers, Inc. Civil · Structural · Survey Section 8. Drainage Report Date: April 10, 2025 Page 1 of 2 Drainage Report Map 001- Block 007- Lot 00A Silver Falls Road Proposed Subdivision CLA Engineers, Inc. Civil · Structural · Survey DRAINAGE REPORT Proposed Subdivision Silver Falls Road Montville, Connecticut Prepared for Daniela Gjergjaj Narrative The proposed project is a residential subdivision located on Silver Falls Road (Map 001, Block 007, Lot 00A) in Montville Connecticut. The existing property is approximately 19-acres bounded by Silver Falls Road to the west. The location of the site in reference to the USGS Quad Map is attached as Figure 1. Existing conditions mapping is included in the subdivision plans. The existing site is generally comprised of wooded land with grass & brush. The property is divided by a ridgeline forming 2 watersheds on the property; existing ground elevations on the site range from approximately 212 to 118. Stormwater from the site currently flows via sheet flow to the from the ridgeline to the 24” HDPE on the west and to the wetlands to the east. The proposed development includes a 4-lot residential subdivision. The proposed lots will all front along Silver Falls Road and be served by a common driveway. There is no proposed roadway or public improvements. The proposed site grading has been designed to match the existing drainage patterns as closely as possible. The lot layouts and grading are depicted in the subdivision plans. As a low impact development measure stormwater throughout the site will continue to be managed by sheet flow over and treated by riprap swales and a water quality basin near the wetlands near Silver Falls Road. The watershed #1 draining to the existing 24” hdpe is approximately 129 acres. The proposed development will disturb approximately 4.4 acres within this watershed. The land use within the work area will change from primarily woods, brush, and grass to residential that includes approximately 2 acres of lawn within the development. Based on the magnitude of the development within the watershed and the difference in land use for the residential development, the impact to the peak stormwater runoff rates will be negligible. In our opinion the proposed development will have no negative impact to the peak flow rates to the existing pond, wetlands, 24” hdpe, and existing beyond the downstream property boundary. The watershed #2 draining to northeasterly wetlands is approximately 257 acres. The proposed development will disturb approximately 1.0 acre within this watershed. The land use within the work area will change from primarily woods, brush, and grass to residential that includes approximately .5 acres of lawn within the development. Based on the magnitude of the Date: April 10, 2025 Page 2 of 2 Drainage Report Map 001- Block 007- Lot 00A Silver Falls Road Proposed Subdivision CLA Engineers, Inc. Civil · Structural · Survey development within the watershed and the difference in land use for the residential development, the impact to the peak stormwater runoff rates will be negligible. In our opinion the proposed development will have no negative impact on the peak flow rates to the existing wetlands or existing land beyond the downstream boundary. Method: The site hydraulic analysis was performed using the SCS TR-55 method utilizing the Hydraflow Hydrographs Extension for AutoCAD. Water quality volume and groundwater recharge volume calculations were performed as outlined in the 2024 Connecticut Stormwater Quality Manual (Section 7.4.1 and Section 7.5.1 respectively). Runoff curve numbers for the existing conditions and post development conditions were compiled from Table 2-2 of TR-55 due to the minimal changes within the watershed the composite curve numbers remained the same for both pre and post construction. Stormwater Quality To meet the Connecticut DEEP stormwater discharge water quality requirements low impact development measures have been designed for the site in accordance with the 2024 Connecticut Stormwater Quality Manual to treat the proposed run-off. Stormwater run-off from each area of development will run to a water quality basin or underground chambers designed to treat water quality volumes as shown on the subdivision plans. Water quality volumes are shown on the detail sheet of the subdivision plans. CLA Engineers, Inc. Robert A. DeLuca, P.E. Hydrograph Summary Report 1 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 3.955 6 792 75,908 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 7.047 6 828 152,683 ------ ------ ------ Existing watershed #2 3 SCS Runoff 3.955 6 792 75,908 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 7.047 6 828 152,683 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 1 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 3.955 cfs Storm frequency = 1 yrs Time to peak = 792 min Time interval = 6 min Hyd. volume = 75,908 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 2.89 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 2 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) Existing Watershed #1 Hyd. No. 1 -- 1 Year Hyd No. 1 TR55 Tc Worksheet 3 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hyd. No. 1 Existing Watershed #1 Description A B C Totals Sheet Flow Manning's n-value = 0.800 0.011 0.011 Flow length (ft) = 150.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.37 0.00 0.00 Land slope (%) = 4.00 0.00 0.00 Travel Time (min)=38.19 +0.00 +0.00 =38.19 Shallow Concentrated Flow Flow length (ft) = 670.00 880.00 0.00 Watercourse slope (%) = 4.20 7.00 0.00 Surface description = Unpaved Unpaved Paved Average velocity (ft/s)=3.31 4.27 0.00 Travel Time (min)=3.38 +3.44 +0.00 =6.81 Channel Flow X sectional flow area (sqft) = 16.00 0.00 0.00 Wetted perimeter (ft) = 8.00 0.00 0.00 Channel slope (%) = 7.40 0.00 0.00 Manning's n-value = 0.050 0.015 0.015 Velocity (ft/s)=12.90 0.00 0.00 Flow length (ft) ({0})1430.0 0.0 0.0 Travel Time (min)=1.85 +0.00 +0.00 =1.85 Total Travel Time, Tc .............................................................................. 46.90 min Precipitation Report 4 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 1 yrs Time interval = 6 min Total precip. = 2.8900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 1 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 7.047 cfs Storm frequency = 1 yrs Time to peak = 828 min Time interval = 6 min Hyd. volume = 152,683 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 2.89 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 5 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) Existing watershed #2 Hyd. No. 2 -- 1 Year Hyd No. 2 TR55 Tc Worksheet 6 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hyd. No. 2 Existing watershed #2 Description A B C Totals Sheet Flow Manning's n-value = 0.800 0.011 0.011 Flow length (ft) = 150.0 0.0 0.0 Two-year 24-hr precip. (in) = 3.37 0.00 0.00 Land slope (%) = 5.30 0.00 0.00 Travel Time (min)=34.12 +0.00 +0.00 =34.12 Shallow Concentrated Flow Flow length (ft) = 1040.00 1200.00 3250.00 Watercourse slope (%) = 4.20 12.70 1.00 Surface description = Unpaved Unpaved Unpaved Average velocity (ft/s)=3.31 5.75 1.61 Travel Time (min)=5.24 +3.48 +33.57 =42.29 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 .............................................................................. 76.40 min Precipitation Report 7 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 1 yrs Time interval = 6 min Total precip. = 2.8900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 1 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 3.955 cfs Storm frequency = 1 yrs Time to peak = 792 min Time interval = 6 min Hyd. volume = 75,908 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 2.89 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 8 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 Watershed #1 Hyd. No. 3 -- 1 Year Hyd No. 3 Precipitation Report 9 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 1 yrs Time interval = 6 min Total precip. = 2.8900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 1 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 7.047 cfs Storm frequency = 1 yrs Time to peak = 828 min Time interval = 6 min Hyd. volume = 152,683 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 2.89 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 10 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) Proposed Watershed #2 Hyd. No. 4 -- 1 Year Hyd No. 4 TR55 Tc Worksheet 11 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hyd. No. 4 Proposed Watershed #2 Description A B C Totals Sheet Flow Manning's n-value = 0.000 0.000 0.000 Flow length (ft) = 0.0 0.0 0.0 Two-year 24-hr precip. (in) = 0.00 0.00 0.00 Land slope (%) = 0.00 0.00 0.00 Travel Time (min)=0.00 +0.00 +0.00 =0.00 Shallow Concentrated Flow Flow length (ft) = 0.00 0.00 0.00 Watercourse slope (%) = 0.00 0.00 0.00 Surface description = 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) = 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 = 0.000 0.000 0.000 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 .............................................................................. 76.40 min Precipitation Report 12 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 1 yrs Time interval = 6 min Total precip. = 2.8900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 1 Year Hydrograph Summary Report 13 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 10.87 6 774 150,229 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 18.07 6 804 302,172 ------ ------ ------ Existing watershed #2 3 SCS Runoff 10.87 6 774 150,229 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 18.07 6 804 302,172 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 2 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 10.87 cfs Storm frequency = 2 yrs Time to peak = 774 min Time interval = 6 min Hyd. volume = 150,229 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 3.45 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 14 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 10.00 10.00 12.00 12.00 Q (cfs) Time (min) Existing Watershed #1 Hyd. No. 1 -- 2 Year Hyd No. 1 Precipitation Report 15 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 2 yrs Time interval = 6 min Total precip. = 3.4500 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 2 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 18.07 cfs Storm frequency = 2 yrs Time to peak = 804 min Time interval = 6 min Hyd. volume = 302,172 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 3.45 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 16 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 3.00 3.00 6.00 6.00 9.00 9.00 12.00 12.00 15.00 15.00 18.00 18.00 21.00 21.00 Q (cfs) Time (min) Existing watershed #2 Hyd. No. 2 -- 2 Year Hyd No. 2 Precipitation Report 17 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 2 yrs Time interval = 6 min Total precip. = 3.4500 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 2 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 10.87 cfs Storm frequency = 2 yrs Time to peak = 774 min Time interval = 6 min Hyd. volume = 150,229 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 3.45 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 18 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 10.00 10.00 12.00 12.00 Q (cfs) Time (min) Proposed Watershed #1 Hyd. No. 3 -- 2 Year Hyd No. 3 Precipitation Report 19 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 2 yrs Time interval = 6 min Total precip. = 3.4500 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 2 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 18.07 cfs Storm frequency = 2 yrs Time to peak = 804 min Time interval = 6 min Hyd. volume = 302,172 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 3.45 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 20 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 3.00 3.00 6.00 6.00 9.00 9.00 12.00 12.00 15.00 15.00 18.00 18.00 21.00 21.00 Q (cfs) Time (min) Proposed Watershed #2 Hyd. No. 4 -- 2 Year Hyd No. 4 Precipitation Report 21 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 2 yrs Time interval = 6 min Total precip. = 3.4500 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 2 Year Hydrograph Summary Report 22 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 30.69 6 762 312,529 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 47.71 6 792 628,622 ------ ------ ------ Existing watershed #2 3 SCS Runoff 30.69 6 762 312,529 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 47.71 6 792 628,622 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 5 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 30.69 cfs Storm frequency = 5 yrs Time to peak = 762 min Time interval = 6 min Hyd. volume = 312,529 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 4.37 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 23 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 5.00 5.00 10.00 10.00 15.00 15.00 20.00 20.00 25.00 25.00 30.00 30.00 35.00 35.00 Q (cfs) Time (min) Existing Watershed #1 Hyd. No. 1 -- 5 Year Hyd No. 1 Precipitation Report 24 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 5 yrs Time interval = 6 min Total precip. = 4.3700 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 5 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 47.71 cfs Storm frequency = 5 yrs Time to peak = 792 min Time interval = 6 min Hyd. volume = 628,622 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 4.37 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 25 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 Q (cfs) Time (min) Existing watershed #2 Hyd. No. 2 -- 5 Year Hyd No. 2 Precipitation Report 26 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 5 yrs Time interval = 6 min Total precip. = 4.3700 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 5 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 30.69 cfs Storm frequency = 5 yrs Time to peak = 762 min Time interval = 6 min Hyd. volume = 312,529 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 4.37 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 27 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 5.00 5.00 10.00 10.00 15.00 15.00 20.00 20.00 25.00 25.00 30.00 30.00 35.00 35.00 Q (cfs) Time (min) Proposed Watershed #1 Hyd. No. 3 -- 5 Year Hyd No. 3 Precipitation Report 28 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 5 yrs Time interval = 6 min Total precip. = 4.3700 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 5 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 47.71 cfs Storm frequency = 5 yrs Time to peak = 792 min Time interval = 6 min Hyd. volume = 628,622 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 4.37 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 29 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 Q (cfs) Time (min) Proposed Watershed #2 Hyd. No. 4 -- 5 Year Hyd No. 4 Precipitation Report 30 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 5 yrs Time interval = 6 min Total precip. = 4.3700 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 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.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 5 Year Hydrograph Summary Report 31 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 53.72 6 756 479,613 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 81.68 6 786 964,695 ------ ------ ------ Existing watershed #2 3 SCS Runoff 53.72 6 756 479,613 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 81.68 6 786 964,695 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 10 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 53.72 cfs Storm frequency = 10 yrs Time to peak = 756 min Time interval = 6 min Hyd. volume = 479,613 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 5.14 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 32 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 Q (cfs) Time (min) Existing Watershed #1 Hyd. No. 1 -- 10 Year Hyd No. 1 Precipitation Report 33 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 10 yrs Time interval = 6 min Total precip. = 5.1400 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 10 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 81.68 cfs Storm frequency = 10 yrs Time to peak = 786 min Time interval = 6 min Hyd. volume = 964,695 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 5.14 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 34 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 70.00 70.00 80.00 80.00 90.00 90.00 Q (cfs) Time (min) Existing watershed #2 Hyd. No. 2 -- 10 Year Hyd No. 2 Precipitation Report 35 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 10 yrs Time interval = 6 min Total precip. = 5.1400 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 10 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 53.72 cfs Storm frequency = 10 yrs Time to peak = 756 min Time interval = 6 min Hyd. volume = 479,613 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 5.14 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 36 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 Q (cfs) Time (min) Proposed Watershed #1 Hyd. No. 3 -- 10 Year Hyd No. 3 Precipitation Report 37 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 10 yrs Time interval = 6 min Total precip. = 5.1400 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 10 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 81.68 cfs Storm frequency = 10 yrs Time to peak = 786 min Time interval = 6 min Hyd. volume = 964,695 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 5.14 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 38 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 70.00 70.00 80.00 80.00 90.00 90.00 Q (cfs) Time (min) Proposed Watershed #2 Hyd. No. 4 -- 10 Year Hyd No. 4 Precipitation Report 39 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 10 yrs Time interval = 6 min Total precip. = 5.1400 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 10 Year Hydrograph Summary Report 40 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 91.80 6 756 743,326 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 138.27 6 780 1,495,130 ------ ------ ------ Existing watershed #2 3 SCS Runoff 91.80 6 756 743,326 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 138.27 6 780 1,495,130 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 25 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 91.80 cfs Storm frequency = 25 yrs Time to peak = 756 min Time interval = 6 min Hyd. volume = 743,326 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 6.19 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 41 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 70.00 70.00 80.00 80.00 90.00 90.00 100.00 100.00 Q (cfs) Time (min) Existing Watershed #1 Hyd. No. 1 -- 25 Year Hyd No. 1 Precipitation Report 42 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 25 yrs Time interval = 6 min Total precip. = 6.1900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 25 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 138.27 cfs Storm frequency = 25 yrs Time to peak = 780 min Time interval = 6 min Hyd. volume = 1,495,130 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 6.19 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 43 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 140.00 140.00 Q (cfs) Time (min) Existing watershed #2 Hyd. No. 2 -- 25 Year Hyd No. 2 Precipitation Report 44 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 25 yrs Time interval = 6 min Total precip. = 6.1900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 25 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 91.80 cfs Storm frequency = 25 yrs Time to peak = 756 min Time interval = 6 min Hyd. volume = 743,326 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 6.19 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 45 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 10.00 10.00 20.00 20.00 30.00 30.00 40.00 40.00 50.00 50.00 60.00 60.00 70.00 70.00 80.00 80.00 90.00 90.00 100.00 100.00 Q (cfs) Time (min) Proposed Watershed #1 Hyd. No. 3 -- 25 Year Hyd No. 3 Precipitation Report 46 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 25 yrs Time interval = 6 min Total precip. = 6.1900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 25 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 138.27 cfs Storm frequency = 25 yrs Time to peak = 780 min Time interval = 6 min Hyd. volume = 1,495,130 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 6.19 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 47 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 140.00 140.00 Q (cfs) Time (min) Proposed Watershed #2 Hyd. No. 4 -- 25 Year Hyd No. 4 Precipitation Report 48 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 25 yrs Time interval = 6 min Total precip. = 6.1900 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 25 Year 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 123.39 6 756 963,867 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 186.07 6 774 1,938,727 ------ ------ ------ Existing watershed #2 3 SCS Runoff 123.39 6 756 963,867 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 186.07 6 774 1,938,727 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 50 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 123.39 cfs Storm frequency = 50 yrs Time to peak = 756 min Time interval = 6 min Hyd. volume = 963,867 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 6.98 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 50 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 140.00 140.00 Q (cfs) Time (min) Existing Watershed #1 Hyd. No. 1 -- 50 Year Hyd No. 1 Precipitation Report 51 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 50 yrs Time interval = 6 min Total precip. = 6.9800 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 50 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 186.07 cfs Storm frequency = 50 yrs Time to peak = 774 min Time interval = 6 min Hyd. volume = 1,938,727 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 6.98 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 52 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 30.00 30.00 60.00 60.00 90.00 90.00 120.00 120.00 150.00 150.00 180.00 180.00 210.00 210.00 Q (cfs) Time (min) Existing watershed #2 Hyd. No. 2 -- 50 Year Hyd No. 2 Precipitation Report 53 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 50 yrs Time interval = 6 min Total precip. = 6.9800 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 50 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 123.39 cfs Storm frequency = 50 yrs Time to peak = 756 min Time interval = 6 min Hyd. volume = 963,867 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 6.98 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 54 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 140.00 140.00 Q (cfs) Time (min) Proposed Watershed #1 Hyd. No. 3 -- 50 Year Hyd No. 3 Precipitation Report 55 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 50 yrs Time interval = 6 min Total precip. = 6.9800 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 50 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 186.07 cfs Storm frequency = 50 yrs Time to peak = 774 min Time interval = 6 min Hyd. volume = 1,938,727 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 6.98 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 56 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 30.00 30.00 60.00 60.00 90.00 90.00 120.00 120.00 150.00 150.00 180.00 180.00 210.00 210.00 Q (cfs) Time (min) Proposed Watershed #2 Hyd. No. 4 -- 50 Year Hyd No. 4 Precipitation Report 57 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 50 yrs Time interval = 6 min Total precip. = 6.9800 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 50 Year Hydrograph Summary Report 58 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 159.71 6 750 1,215,255 ------ ------ ------ Existing Watershed #1 2 SCS Runoff 241.25 6 774 2,444,370 ------ ------ ------ Existing watershed #2 3 SCS Runoff 159.71 6 750 1,215,255 ------ ------ ------ Proposed Watershed #1 4 SCS Runoff 241.25 6 774 2,444,370 ------ ------ ------ Proposed Watershed #2 7885 Hydrographs.gpw Return Period: 100 Year Tuesday, 04 / 8 / 2025 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 159.71 cfs Storm frequency = 100 yrs Time to peak = 750 min Time interval = 6 min Hyd. volume = 1,215,255 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 46.90 min Total precip. = 7.82 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(129.000 x 55)] / 129.000 59 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 140.00 140.00 160.00 160.00 Q (cfs) Time (min) Existing Watershed #1 Hyd. No. 1 -- 100 Year Hyd No. 1 Precipitation Report 60 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 1 Existing Watershed #1 Storm Frequency = 100 yrs Time interval = 6 min Total precip. = 7.8200 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 1 : Existing Watershed #1 - 100 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Hydrograph type = SCS Runoff Peak discharge = 241.25 cfs Storm frequency = 100 yrs Time to peak = 774 min Time interval = 6 min Hyd. volume = 2,444,370 cuft Drainage area = 257.000 ac Curve number = 55 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 7.82 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 61 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 40.00 40.00 80.00 80.00 120.00 120.00 160.00 160.00 200.00 200.00 240.00 240.00 280.00 280.00 Q (cfs) Time (min) Existing watershed #2 Hyd. No. 2 -- 100 Year Hyd No. 2 Precipitation Report 62 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 2 Existing watershed #2 Storm Frequency = 100 yrs Time interval = 6 min Total precip. = 7.8200 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 2 : Existing watershed #2 - 100 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Hydrograph type = SCS Runoff Peak discharge = 159.71 cfs Storm frequency = 100 yrs Time to peak = 750 min Time interval = 6 min Hyd. volume = 1,215,255 cuft Drainage area = 129.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 46.90 min Total precip. = 7.82 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(1.000 x 98) + (3.400 x 61) + (124.600 x 55)] / 129.000 63 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 140.00 140.00 160.00 160.00 Q (cfs) Time (min) Proposed Watershed #1 Hyd. No. 3 -- 100 Year Hyd No. 3 Precipitation Report 64 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 3 Proposed Watershed #1 Storm Frequency = 100 yrs Time interval = 6 min Total precip. = 7.8200 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 3 : Proposed Watershed #1 - 100 Year Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Hydrograph type = SCS Runoff Peak discharge = 241.25 cfs Storm frequency = 100 yrs Time to peak = 774 min Time interval = 6 min Hyd. volume = 2,444,370 cuft Drainage area = 257.000 ac Curve number = 55* Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = TR55 Time of conc. (Tc) = 76.40 min Total precip. = 7.82 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cdsShape factor = 484 * Composite (Area/CN) = [(0.850 x 61) + (1.000 x 98) + (255.150 x 55)] / 257.000 65 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Q (cfs) 0.00 0.00 40.00 40.00 80.00 80.00 120.00 120.00 160.00 160.00 200.00 200.00 240.00 240.00 280.00 280.00 Q (cfs) Time (min) Proposed Watershed #2 Hyd. No. 4 -- 100 Year Hyd No. 4 Precipitation Report 66 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Hyd. No. 4 Proposed Watershed #2 Storm Frequency = 100 yrs Time interval = 6 min Total precip. = 7.8200 in Distribution = Custom Storm duration = M:\NOAA Type D Distribution.cds 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 Precip (in) 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 Precip (in) Time (min)Custom Design Storm -- M:\NOAA Type D Distribution.cds Incremental Rainfall Precipitation Hyd. No. 4 : Proposed Watershed #2 - 100 Year Hydraflow Rainfall Report 67 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 Return Intensity-Duration-Frequency Equation Coefficients (FHA) Period (Yrs)B D E (N/A) 1 18.1733 3.5000 0.7010 -------- 2 22.7904 3.9000 0.7142 -------- 3 0.0000 0.0000 0.0000 -------- 5 26.8118 3.1000 0.7005 -------- 10 32.8535 3.8000 0.7098 -------- 25 38.4672 3.6000 0.7049 -------- 50 43.8334 3.7000 0.7074 -------- 100 48.6510 3.7000 0.7060 -------- File name: Brooklyn 2024.IDF Intensity = B / (Tc + D)^E Return Intensity Values (in/hr) Period(Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 4.05 2.93 2.35 1.99 1.74 1.55 1.41 1.29 1.20 1.12 1.05 0.99 2 4.78 3.48 2.79 2.36 2.06 1.84 1.67 1.53 1.42 1.32 1.24 1.17 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 6.19 4.42 3.53 2.97 2.59 2.31 2.09 1.92 1.78 1.66 1.56 1.47 10 7.02 5.10 4.09 3.46 3.02 2.70 2.45 2.25 2.08 1.94 1.82 1.72 25 8.44 6.11 4.90 4.14 3.62 3.23 2.93 2.69 2.49 2.32 2.18 2.06 50 9.49 6.88 5.52 4.67 4.08 3.64 3.30 3.03 2.81 2.62 2.46 2.32 100 10.56 7.67 6.15 5.21 4.55 4.06 3.68 3.38 3.13 2.92 2.74 2.59 Tc = time in minutes. Values may exceed 60. Rainfall Precipitation Table (in) Precip. file name: M:\7000\7300\7386 Reynolds St. Improvements\Studies-Calculations\Danielson storms.pcp Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 2.89 3.45 0.00 4.37 4.15 6.19 6.98 7.82 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 2.89 3.45 0.00 4.37 5.14 6.19 6.98 7.82 Hydraflow Table of Contents 7885 Hydrographs.gpw Hydraflow Hydrographs Extension for Autodesk® Civil 3D® 2019 by Autodesk, Inc. v2020 Tuesday, 04 / 8 / 2025 1 - Year Summary Report......................................................................................................................... 1 Hydrograph Reports................................................................................................................... 2 Hydrograph No. 1, SCS Runoff, Existing Watershed #1.......................................................... 2 TR-55 Tc Worksheet............................................................................................................ 3 Precipitation Report............................................................................................................. 4 Hydrograph No. 2, SCS Runoff, Existing watershed #2........................................................... 5 TR-55 Tc Worksheet............................................................................................................ 6 Precipitation Report............................................................................................................. 7 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1....................................................... 8 Precipitation Report............................................................................................................. 9 Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................10 TR-55 Tc Worksheet..........................................................................................................11 Precipitation Report...........................................................................................................12 2 - Year Summary Report.......................................................................................................................13 Hydrograph Reports.................................................................................................................14 Hydrograph No. 1, SCS Runoff, Existing Watershed #1........................................................14 Precipitation Report...........................................................................................................15 Hydrograph No. 2, SCS Runoff, Existing watershed #2.........................................................16 Precipitation Report...........................................................................................................17 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1.....................................................18 Precipitation Report...........................................................................................................19 Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................20 Precipitation Report...........................................................................................................21 5 - Year Summary Report.......................................................................................................................22 Hydrograph Reports.................................................................................................................23 Hydrograph No. 1, SCS Runoff, Existing Watershed #1........................................................23 Precipitation Report...........................................................................................................24 Hydrograph No. 2, SCS Runoff, Existing watershed #2.........................................................25 Precipitation Report...........................................................................................................26 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1.....................................................27 Precipitation Report...........................................................................................................28 Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................29 Precipitation Report...........................................................................................................30 10 - Year Summary Report.......................................................................................................................31 Hydrograph Reports.................................................................................................................32 Hydrograph No. 1, SCS Runoff, Existing Watershed #1........................................................32 Precipitation Report...........................................................................................................33 Hydrograph No. 2, SCS Runoff, Existing watershed #2.........................................................34 Precipitation Report...........................................................................................................35 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1.....................................................36 Precipitation Report...........................................................................................................37 Contents continued...7885 Hydrographs.gpw Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................38 Precipitation Report...........................................................................................................39 25 - Year Summary Report.......................................................................................................................40 Hydrograph Reports.................................................................................................................41 Hydrograph No. 1, SCS Runoff, Existing Watershed #1........................................................41 Precipitation Report...........................................................................................................42 Hydrograph No. 2, SCS Runoff, Existing watershed #2.........................................................43 Precipitation Report...........................................................................................................44 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1.....................................................45 Precipitation Report...........................................................................................................46 Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................47 Precipitation Report...........................................................................................................48 50 - Year Summary Report.......................................................................................................................49 Hydrograph Reports.................................................................................................................50 Hydrograph No. 1, SCS Runoff, Existing Watershed #1........................................................50 Precipitation Report...........................................................................................................51 Hydrograph No. 2, SCS Runoff, Existing watershed #2.........................................................52 Precipitation Report...........................................................................................................53 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1.....................................................54 Precipitation Report...........................................................................................................55 Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................56 Precipitation Report...........................................................................................................57 100 - Year Summary Report.......................................................................................................................58 Hydrograph Reports.................................................................................................................59 Hydrograph No. 1, SCS Runoff, Existing Watershed #1........................................................59 Precipitation Report...........................................................................................................60 Hydrograph No. 2, SCS Runoff, Existing watershed #2.........................................................61 Precipitation Report...........................................................................................................62 Hydrograph No. 3, SCS Runoff, Proposed Watershed #1.....................................................63 Precipitation Report...........................................................................................................64 Hydrograph No. 4, SCS Runoff, Proposed Watershed #2....................................................65 Precipitation Report...........................................................................................................66 IDF Report..................................................................................................................67