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HomeMy WebLinkAboutDrainage ReportPage 2 J:\221\1040 - Lot 6, Mineota Ridge - Silt\Civil\Reports\Drainage\2211040 - DRAINAGE STUDY LOT 6 MINEOTA.doc TABLE OF CONTENTS SECTION PAGE I. GENERAL LOCATION AND DESCRIPTION ................................................................ 3 II. HYDROLOGY ................................................................................................................... 3 III. EXISTING CONDITIONS ................................................................................................. 4 IV. PROPOSED CONDITIONS ............................................................................................... 4 V. RESULTS AND RECOMMENDATIONS ........................................................................ 5 VI. CONCLUSION ................................................................................................................... 5 VII. REFERENCES ................................................................................................................... 5 APPENDICES: 1. Vicinity Map (8.5”x11”) 2. SCS Soils Map (8.5”x11”) 3. Existing and Proposed Drainage Conditions (24”x36”) 4. NOAA TABLE SILT AREA Storm Rainfall (8.5”x11”) 5. Hydrologic Computations 6. Hydraulic Computations Page 3 J:\221\1040 - Lot 6, Mineota Ridge - Silt\Civil\Reports\Drainage\2211040 - DRAINAGE STUDY LOT 6 MINEOTA.doc I. GENERAL LOCATION AND DESCRIPTION A. Location The subject property is located at Lot 6 in the Mineota Ridge Subdivision within the County of Garfield, State of Colorado. A Vicinity Map has been included as Appendix 1. B. Description of Existing Property The existing lot is approximately 14.352 acres. The lot is currently undeveloped and consists of open space with sagebrush ground cover. The site is bordered by private properties on all sides. The site is accessed by a private road which traverses the property west to east near the northern portion of the site. Generally site drainage flows from south to north across the property. Existing site drainage discharges offsite via sheet flow at the northern property line to the adjacent private property. Grades on the property range from 6-percent to 50-percent, approximately. C. Soils Description This site primarily lies within two SCS mapping unit types: 51 – Olney loam, 6 to 12 percent slopes. The Soil Conservation Service describes the soil as well- drained with medium runoff, moderately high to high permeability, and moderate water storage capacity. The soil is classified as hydrologic soil group ‘B’. 66—Torriorthents-Camborthids-Rock outcrop complex, steep. The Soil Conservation Service describes the soil as well-drained with high runoff, moderately low to moderately high permeability, and very low water storage capacity. The soil is classified as hydrologic soil group ‘D’. Additional soils information can be referenced in Appendix 2. II. HYDROLOGY The hydrologic methods for this study are outlined in the Soil Conservation Service (SCS) publication "Procedures for Determining Peak Flows in Colorado" (1980) and the computer program AutoCAD Hydrology TR-55 Tabular Method. Peak flows in this area will be rainfall derived. Rainfall amounts were obtained using the Precipitation – Frequency Atlas of the Western United States published by the National Oceanic and Atmospheric Administration (NOAA). Using this atlas the precipitation corresponding to the 2-yr, 24 hr storm event is 1.06 inches; the 25-yr, 24-hr storm event is 1.79 inches; and the 100-yr, 24-hr storm event produces 2.27 inches of precipitation for the Silt area. Page 4 J:\221\1040 - Lot 6, Mineota Ridge - Silt\Civil\Reports\Drainage\2211040 - DRAINAGE STUDY LOT 6 MINEOTA.doc III. EXISTING CONDITIONS The project site is currently on an undeveloped parcel. A majority of the site consists of open space with sagebrush and grasses. Runoff curve numbers of 59 and 77 were selected for hydrologic soil group types “B” and “D” respectively for “Sagebrush with grass understory”; Poor and Fair condition (average) based on TR-55 table 2-2d. The scope of analysis for this project consists of the drainage basin relative to the disturbance area for the proposed improvements, approximately 8.364 acres. Overall, existing drainage patterns will generally be maintained with site discharges near the northeast portion of the site. The existing site has been analyzed with a single basin which analyzes the existing conditions. The existing basin includes the proposed gravel driveway, single family residence and future garage area. Hydrologic analysis has been conducted per Section 7-204(C)(3)a. of the Garfield County Land Use Code: Detention facilities shall ensure the post-development peak discharge rate does not exceed the pre-development peak discharge rate for the 2-year and 25-year return frequency, 24- hour duration storm. In determining Runoff rates, the entire area contributing Runoff shall be considered, including any existing offsite contribution. Pre-development conditions will be compared to the post-development condition with the change in impervious area. The existing and proposed basins have been illustrated on the existing and proposed drainage conditions maps included as Appendix 3 of this report. The Hydraflow SCS Hydrology calculator in AutoCAD was used to determine runoff and time of concentrations for each basin. Calculated flows for the existing basin is tabulated in Table 1 below. Complete drainage calculations are included in the appendices. Table 1. Existing Basin Characteristics BASIN AREA (acre) CN Tc (min) 25-YR PEAK FLOW (cfs) 100-YR PEAK FLOW (cfs) EX-1 8.364 68 16.0 0.47 1.98 IV. PROPOSED CONDITIONS Proposed development includes construction of a 2,108 square-foot single-family residence roof footprint and gravel driveway. Future construction includes a garage which is located within a currently proposed gravel parking area, and an approximately 2450-sf shop east of the single-family residence. Analysis for the post development condition includes the impervious area from the future garage and shop. The site has been analyzed as a single basin, PR-1. This will allow for a comparison of the same area between existing and proposed conditions to establish a required detention volume to release historic runoff rates during the 25-year design storm event. Existing drainage patterns are generally unchanged per the proposed single-family residence. A dry detention pond is proposed near the northeast corner of the site that will receive runoff from Page 5 J:\221\1040 - Lot 6, Mineota Ridge - Silt\Civil\Reports\Drainage\2211040 - DRAINAGE STUDY LOT 6 MINEOTA.doc the proposed improvements including proposed impervious areas. Drainage from the proposed impervious areas is collected in swales and is piped to a surface discharge north of the existing private driveway which traverses the property. Drainage then sheet flows north and is routed to the detention pond by a proposed swale near the north property boundary. Basin characteristics and calculated flows are tabulated in Table 2 below. Complete drainage calculations are included in the appendices and a proposed basin map showing the proposed basin delineation and characteristics can be referenced in Appendix 3. Table 2. Proposed Onsite Basin Characteristics BASIN AREA (acre) CN Tc (min) 25-YR PEAK FLOW (cfs) 100-YR PEAK FLOW (cfs) PR-1 8.364 70 16 0.42 2.57 V. RESULTS AND RECOMMENDATIONS This proposed development has a net increase in runoff from the site prior to detention due to the increased impervious area. The proposed detention pond receives runoff from proposed basin PR-1. The pond has an outlet pipe at the pond bottom that will release at the pre-development flow rate. An overflow weir will safely discharge 100-year or greater storm events along historic drainage patterns to the north/northeast where it discharges offsite. The proposed detention ponds at the northeast corner of the site receives runoff from the proposed improvements will provide 950 cubic feet of detention to maintain the pre-development 25-year runoff rate from the site. VI. CONCLUSION The proposed single-family residence at Lot 6 Mineota Ridge Subdivision will require drainage swales, culverts, storm piping and a detention pond for conveyance and detention. The analysis for the area affected by the drainage was compared to pre-development conditions prior to the proposed improvements in order to address additional detention storage to mitigate any additional impervious area. The proposed construction maintains the peak discharge leaving the site as required for the 25-year event. The change in flow characteristics is minor and will not adversely affect downstream landowners or structures. Water quality pollutant removal will be provided by the proposed detention pond via detention up to and including the 25-year storm event. VII. REFERENCES United States Department of Agriculture, Soil Conservation Service: Soil Survey of Aspen-Gypsum Area, Colorado, Parts of Eagle, and Garfield Counties, May 1992. APPENDIX 1 VICINITY MAP Garfield County, CO Developed by Account Number R084680 Par cel Number 217913300743 Acr es 14 Land SqFt 0 T ax Ar ea 023 2019 Mill Levy 73.8920 Physical Address 0 SILT 81652 Ow ner Address FERGUSON, C ODY G & KARLA C & SMITH, FRAN PO BOX 792 SILT C O 81652 2019 Total Actual Value $32,720 Last 2 Sa les Date Pr ice 9/1/2021 $0 9/1/2021 $0 Date created: 2/10/2022 Last Data Uploa ded: 2/10/2022 2:12:19 AM 2,000 ft Overvi ew Legend Parcels Roa ds Highw ays Limited Access Highwa y Major Road Loca l Roa d Minor Road Other Road Ra mp Ferry Pedestria n Way Lakes & River s APPENDIX 2 SCS SOILS MAP Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties (2211040 - EX-1 BOUNDARY) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 1 of 4437815043781904378230437827043783104378350437839043784304378470437815043781904378230437827043783104378350437839043784304378470274820274860274900274940274980275020275060 274820 274860 274900 274940 274980 275020 275060 39° 31' 35'' N 107° 37' 11'' W39° 31' 35'' N107° 37' 0'' W39° 31' 24'' N 107° 37' 11'' W39° 31' 24'' N 107° 37' 0'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 50 100 200 300 Feet 0 25 50 100 150 Meters Map Scale: 1:1,740 if printed on A portrait (8.5" x 11") 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 1:24,000. 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: Rifle Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 14, Sep 2, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Dec 31, 2009—Oct 12, 2017 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. Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties (2211040 - EX-1 BOUNDARY) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 51 Olney loam, 6 to 12 percent slopes B 4.3 51.6% 66 Torriorthents- Camborthids-Rock outcrop complex, steep D 4.1 48.4% Totals for Area of Interest 8.4 100.0% Description 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. 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. Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - EX-1 BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 3 of 4 Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - EX-1 BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 4 of 4 Rifle Area, Colorado, Parts of Garfield and Mesa Counties 51—Olney loam, 6 to 12 percent slopes Map Unit Setting National map unit symbol: jnym Elevation: 5,000 to 6,500 feet Farmland classification: Farmland of statewide importance Map Unit Composition Olney and similar soils:85 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Olney Setting Landform:Alluvial fans, valley sides Down-slope shape:Linear, convex Across-slope shape:Linear, convex Parent material:Alluvium derived from sandstone and shale Typical profile H1 - 0 to 12 inches: loam H2 - 12 to 33 inches: sandy clay loam H3 - 33 to 43 inches: gravelly sandy clay loam H4 - 43 to 60 inches: very gravelly sandy loam Properties and qualities Slope:6 to 12 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.60 to 2.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:15 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Moderate (about 7.6 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Ecological site: R048AY306UT - Upland Loam (Wyoming Big Sagebrush) Map Unit Description: Olney loam, 6 to 12 percent slopes---Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - SOILS BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 1 of 2 Hydric soil rating: No Data Source Information Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 14, Sep 2, 2021 Map Unit Description: Olney loam, 6 to 12 percent slopes---Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - SOILS BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 2 of 2 Rifle Area, Colorado, Parts of Garfield and Mesa Counties 66—Torriorthents-Camborthids-Rock outcrop complex, steep Map Unit Setting National map unit symbol: jnz4 Elevation: 5,000 to 8,500 feet Mean annual precipitation: 10 to 15 inches Mean annual air temperature: 39 to 46 degrees F Frost-free period: 80 to 105 days Farmland classification: Not prime farmland Map Unit Composition Torriorthents, steep, and similar soils:45 percent Camborthids, steep, and similar soils:20 percent Rock outcrop, steep:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Torriorthents, Steep Setting Landform:Mountainsides Landform position (two-dimensional):Footslope Landform position (three-dimensional):Mountainflank, base slope Down-slope shape:Convex Across-slope shape:Convex Parent material:Stony, basaltic alluvium derived from sandstone and shale Typical profile H1 - 0 to 4 inches: variable H2 - 4 to 30 inches: fine sandy loam H3 - 30 to 34 inches: unweathered bedrock Properties and qualities Slope:15 to 70 percent Depth to restrictive feature:4 to 30 inches to lithic bedrock Drainage class:Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:5 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Very low (about 2.4 inches) Map Unit Description: Torriorthents-Camborthids-Rock outcrop complex, steep---Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - SOILS BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 1 of 3 Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: D Hydric soil rating: No Description of Camborthids, Steep Setting Landform:Mountainsides Landform position (two-dimensional):Footslope Landform position (three-dimensional):Mountainflank, base slope Down-slope shape:Convex Across-slope shape:Convex Parent material:Stony, basaltic alluvium derived from sandstone and shale Typical profile H1 - 0 to 4 inches: variable H2 - 4 to 30 inches: clay loam H3 - 30 to 34 inches: unweathered bedrock Properties and qualities Slope:15 to 65 percent Depth to restrictive feature:15 to 60 inches to lithic bedrock Drainage class:Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:10 percent Gypsum, maximum content:2 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 4.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7e Hydrologic Soil Group: C Hydric soil rating: No Description of Rock Outcrop, Steep Setting Landform:Mountainsides Landform position (three-dimensional):Free face Down-slope shape:Convex Across-slope shape:Convex Typical profile H1 - 0 to 60 inches: unweathered bedrock Map Unit Description: Torriorthents-Camborthids-Rock outcrop complex, steep---Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - SOILS BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 2 of 3 Properties and qualities Slope:15 to 70 percent Depth to restrictive feature:0 inches to paralithic bedrock Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately high (0.00 to 0.20 in/hr) Available water supply, 0 to 60 inches: Very low (about 0.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8s Hydric soil rating: No Data Source Information Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and Mesa Counties Survey Area Data: Version 14, Sep 2, 2021 Map Unit Description: Torriorthents-Camborthids-Rock outcrop complex, steep---Rifle Area, Colorado, Parts of Garfield and Mesa Counties 2211040 - SOILS BOUNDARY Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 12/30/2021 Page 3 of 3 APPENDIX 3 EXISTING & PROPOSED DRAINAGE CONDITIONS OEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEXXXXXXXXXXXXXXXXXXXXXXXXYARDHYDBYNO.DATEPROJECT NO.REVISIONHIGH COUNTRY ENGINEERING, INC. PHONE (970) 945-8676 - FAX (970) 945-2555 www.hceng.com drawn by: checked by: date: file: 1517 BLAKE AVENUE, STE 101, GLENWOOD SPRINGS, CO 81601 COLORADO 811CALL BEFOREYOU DIGUtility NotificationCenter of Colorado2211040.00FERGUSON-SMITH RESIDENCE GARFIELD COUNTY, CO LOT 6, MINEOTA ESTATES HCE HCE 2/11/2022EXDREXISTING CONDITIONS DRAINAGE MAP EXDR OEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEXXXXXXXXXXXXXXXXXXXXXXXXYARDHYDPROPOSEDRESIDENCEMAIN FF: 5704.08LOWER FF: 5695.00PARKING AREABYNO.DATEPROJECT NO.REVISIONHIGH COUNTRY ENGINEERING, INC. PHONE (970) 945-8676 - FAX (970) 945-2555 www.hceng.com drawn by: checked by: date: file: 1517 BLAKE AVENUE, STE 101, GLENWOOD SPRINGS, CO 81601 COLORADO 811CALL BEFOREYOU DIGUtility NotificationCenter of Colorado2211040.00FERGUSON-SMITH RESIDENCE GARFIELD COUNTY, CO LOT 6, MINEOTA ESTATES HCE HCE 2/11/2022PRDR-1EXISTING DRAINAGE CONDITIONS MAP PRDR OEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEOEXXXXXXXXXXXXXXXXXXXXXXXXYARDHYDPROPOSEDRESIDENCEMAIN FF: 5704.08LOWER FF: 5695.00PARKING AREABYNO.DATEPROJECT NO.REVISIONHIGH COUNTRY ENGINEERING, INC. PHONE (970) 945-8676 - FAX (970) 945-2555 www.hceng.com drawn by: checked by: date: file: 1517 BLAKE AVENUE, STE 101, GLENWOOD SPRINGS, CO 81601 COLORADO 811CALL BEFOREYOU DIGUtility NotificationCenter of Colorado2211040.00FERGUSON-SMITH RESIDENCE GARFIELD COUNTY, CO LOT 6, MINEOTA ESTATES HCE HCE 2/10/2022PRDR-2PROPOSED DRAINAGE SUB-BASIN MAP PRDR APPENDIX 4 NOAA TABLE – SILT AREA STORM RAINFALL NOAA Atlas 14, Volume 8, Version 2 Location name: Silt, Colorado, USA* Latitude: 39.5251°, Longitude: -107.6183° Elevation: 5705.69 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Deborah Martin, Sandra Pavlovic, Ishani Roy, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Michael Yekta, Geoffery Bonnin 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 0.117 (0.091‑0.149) 0.151 (0.118‑0.193) 0.211 (0.164‑0.270) 0.264 (0.204‑0.339) 0.340 (0.256‑0.462) 0.403 (0.295‑0.554) 0.469 (0.331‑0.663) 0.538 (0.365‑0.787) 0.635 (0.414‑0.959) 0.712 (0.450‑1.09) 10-min 0.171 (0.134‑0.218) 0.222 (0.173‑0.283) 0.309 (0.240‑0.396) 0.386 (0.299‑0.497) 0.498 (0.375‑0.676) 0.590 (0.432‑0.811) 0.686 (0.485‑0.971) 0.788 (0.534‑1.15) 0.930 (0.606‑1.40) 1.04 (0.660‑1.59) 15-min 0.208 (0.163‑0.265) 0.270 (0.211‑0.345) 0.377 (0.293‑0.482) 0.471 (0.364‑0.606) 0.608 (0.457‑0.824) 0.720 (0.527‑0.990) 0.837 (0.591‑1.19) 0.961 (0.651‑1.41) 1.13 (0.738‑1.71) 1.27 (0.804‑1.94) 30-min 0.266 (0.208‑0.339) 0.354 (0.276‑0.451) 0.500 (0.389‑0.640) 0.625 (0.484‑0.804) 0.803 (0.600‑1.08) 0.944 (0.689‑1.29) 1.09 (0.767‑1.53) 1.24 (0.837‑1.80) 1.44 (0.938‑2.17) 1.60 (1.01‑2.45) 60-min 0.348 (0.272‑0.443) 0.441 (0.344‑0.562) 0.598 (0.465‑0.765) 0.733 (0.567‑0.943) 0.924 (0.692‑1.25) 1.08 (0.787‑1.48) 1.24 (0.871‑1.74) 1.40 (0.946‑2.04) 1.62 (1.06‑2.44) 1.80 (1.14‑2.75) 2-hr 0.429 (0.338‑0.541) 0.528 (0.416‑0.667) 0.696 (0.546‑0.882) 0.840 (0.655‑1.07) 1.05 (0.791‑1.39) 1.21 (0.893‑1.64) 1.38 (0.984‑1.92) 1.56 (1.07‑2.24) 1.80 (1.19‑2.68) 1.99 (1.27‑3.00) 3-hr 0.500 (0.396‑0.628) 0.590 (0.467‑0.742) 0.745 (0.588‑0.939) 0.881 (0.691‑1.12) 1.08 (0.823‑1.43) 1.24 (0.922‑1.67) 1.41 (1.01‑1.95) 1.59 (1.09‑2.27) 1.84 (1.22‑2.71) 2.03 (1.31‑3.04) 6-hr 0.625 (0.500‑0.777) 0.720 (0.575‑0.896) 0.882 (0.702‑1.10) 1.02 (0.809‑1.28) 1.22 (0.940‑1.60) 1.39 (1.04‑1.84) 1.55 (1.13‑2.12) 1.73 (1.20‑2.43) 1.98 (1.32‑2.86) 2.17 (1.41‑3.19) 12-hr 0.767 (0.619‑0.945) 0.885 (0.713‑1.09) 1.08 (0.869‑1.34) 1.25 (0.999‑1.55) 1.49 (1.16‑1.92) 1.68 (1.27‑2.20) 1.88 (1.38‑2.53) 2.09 (1.46‑2.89) 2.37 (1.60‑3.38) 2.59 (1.70‑3.75) 24-hr 0.925 (0.753‑1.13) 1.06 (0.866‑1.30) 1.30 (1.05‑1.59) 1.50 (1.21‑1.85) 1.79 (1.40‑2.29) 2.03 (1.55‑2.62) 2.27 (1.67‑3.01) 2.52 (1.78‑3.44) 2.86 (1.95‑4.02) 3.13 (2.08‑4.46) 2-day 1.09 (0.894‑1.31) 1.24 (1.02‑1.50) 1.51 (1.24‑1.83) 1.74 (1.42‑2.12) 2.08 (1.64‑2.62) 2.34 (1.81‑3.00) 2.62 (1.96‑3.44) 2.92 (2.09‑3.93) 3.32 (2.29‑4.60) 3.64 (2.44‑5.10) 3-day 1.18 (0.974‑1.41) 1.36 (1.12‑1.64) 1.67 (1.37‑2.01) 1.93 (1.58‑2.34) 2.30 (1.83‑2.88) 2.59 (2.01‑3.29) 2.90 (2.17‑3.76) 3.21 (2.31‑4.28) 3.64 (2.52‑4.98) 3.97 (2.68‑5.51) 4-day 1.26 (1.04‑1.50) 1.46 (1.21‑1.74) 1.79 (1.48‑2.15) 2.07 (1.70‑2.49) 2.46 (1.96‑3.06) 2.77 (2.16‑3.49) 3.09 (2.32‑3.98) 3.41 (2.46‑4.51) 3.84 (2.68‑5.23) 4.18 (2.84‑5.77) 7-day 1.48 (1.24‑1.76) 1.69 (1.41‑2.01) 2.04 (1.70‑2.43) 2.33 (1.93‑2.79) 2.74 (2.20‑3.37) 3.06 (2.40‑3.81) 3.38 (2.57‑4.31) 3.71 (2.71‑4.86) 4.16 (2.92‑5.59) 4.50 (3.08‑6.14) 10-day 1.69 (1.42‑1.99) 1.90 (1.59‑2.24) 2.25 (1.88‑2.66) 2.54 (2.12‑3.02) 2.95 (2.38‑3.61) 3.28 (2.59‑4.06) 3.61 (2.75‑4.57) 3.94 (2.89‑5.12) 4.40 (3.11‑5.86) 4.75 (3.27‑6.41) 20-day 2.23 (1.90‑2.61) 2.48 (2.10‑2.90) 2.88 (2.43‑3.38) 3.21 (2.70‑3.78) 3.67 (2.99‑4.43) 4.03 (3.21‑4.92) 4.39 (3.38‑5.47) 4.76 (3.52‑6.07) 5.24 (3.74‑6.86) 5.61 (3.91‑7.45) 30-day 2.68 (2.29‑3.11) 2.97 (2.54‑3.46) 3.45 (2.93‑4.02) 3.84 (3.25‑4.49) 4.37 (3.57‑5.22) 4.77 (3.82‑5.77) 5.17 (4.00‑6.38) 5.56 (4.14‑7.03) 6.08 (4.36‑7.87) 6.47 (4.53‑8.50) 45-day 3.24 (2.78‑3.74) 3.61 (3.10‑4.18) 4.21 (3.60‑4.88) 4.69 (3.99‑5.45) 5.32 (4.37‑6.30) 5.79 (4.66‑6.94) 6.25 (4.87‑7.64) 6.69 (5.01‑8.37) 7.26 (5.24‑9.28) 7.66 (5.41‑9.97) 60-day 3.72 (3.21‑4.28) 4.17 (3.59‑4.80) 4.89 (4.19‑5.63) 5.45 (4.65‑6.31) 6.19 (5.09‑7.27) 6.73 (5.43‑8.01) 7.24 (5.66‑8.78) 7.73 (5.81‑9.58) 8.33 (6.03‑10.6) 8.76 (6.21‑11.3) 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 (for a 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 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. Back to Top PF graphical APPENDIX 5 HYDROLOGIC COMPUTATIONS Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Tuesday, Jan 4 2022 EX-1 Hydrograph type = SCS Peak discharge (cfs) = 0.466 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 8.200 Curve number (CN) = 68 Basin Slope (%)= See Worksheet Hydraulic length (ft)= See Worksheet Tc method = TR55 Time of conc. (min) = 16 Total precip. (in) = 1.79 Storm Distribution = Type II Storm duration (hrs) = 24 Shape factor = 484 Hydrograph Volume = 3,907 (cuft); 0.090 (acft) 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 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 (hrs) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 0.47 (cfs) TR55 Tc Worksheet Hydraflow Express by Intelisolve SCS EX-1 Description A B C Totals Sheet Flow Manning's n-value = 0.130 0.011 0.011 Flow length (ft) = 300.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 1.06 0.00 0.00 Land slope (%) = 27.00 0.00 0.00 Travel Time (min) = 12.91 + 0.00 + 0.00 = 12.91 Shallow Concentrated Flow Flow length (ft) = 699.00 184.80 0.00 Watercourse slope (%) = 18.90 2.14 0.00 Surface description = Unpaved Unpaved Paved Average velocity (ft/s) = 7.01 2.36 0.00 Travel Time (min) = 1.66 + 1.30 + 0.00 = 2.97 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 Travel Time (min) = 0 + 0 + 0 = 0.00 Total Travel Time, Tc .............................................................................. 16.00 min Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Tuesday, Jan 4 2022 EX-1 Hydrograph type = SCS Peak discharge (cfs) = 1.984 Storm frequency (yrs) = 100 Time interval (min) = 1 Drainage area (ac) = 8.200 Curve number (CN) = 68 Basin Slope (%)= See Worksheet Hydraulic length (ft)= See Worksheet Tc method = TR55 Time of conc. (min) = 16 Total precip. (in) = 2.27 Storm Distribution = Type II Storm duration (hrs) = 24 Shape factor = 484 Hydrograph Volume = 8,818 (cuft); 0.202 (acft) 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (hrs) Runoff Hydrograph 100-yr frequency Runoff Hyd - Qp = 1.98 (cfs) Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jan 7 2022 PR-1 Hydrograph type = SCS Peak discharge (cfs) = 0.849 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 8.360 Curve number (CN) = 70 Basin Slope (%)= See Worksheet Hydraulic length (ft)= See Worksheet Tc method = TR55 Time of conc. (min) = 16 Total precip. (in) = 1.79 Storm Distribution = Type II Storm duration (hrs) = 24 Shape factor = 484 Hydrograph Volume = 5,122 (cuft); 0.118 (acft) 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 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 (hrs) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 0.85 (cfs)Outflow Hyd *Req. Stor = 707 (cuft) * * Estimated TR55 Tc Worksheet Hydraflow Express by Intelisolve SCS PR-1 Description A B C Totals Sheet Flow Manning's n-value = 0.130 0.011 0.011 Flow length (ft) = 300.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 1.06 0.00 0.00 Land slope (%) = 27.00 0.00 0.00 Travel Time (min) = 12.91 + 0.00 + 0.00 = 12.91 Shallow Concentrated Flow Flow length (ft) = 699.00 184.80 0.00 Watercourse slope (%) = 18.90 2.14 0.00 Surface description = Unpaved Unpaved Paved Average velocity (ft/s) = 7.01 2.36 0.00 Travel Time (min) = 1.66 + 1.30 + 0.00 = 2.97 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 Travel Time (min) = 0 + 0 + 0 = 0.00 Total Travel Time, Tc .............................................................................. 16.00 min Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jan 7 2022 PR-1 Hydrograph type = SCS Peak discharge (cfs) = 2.742 Storm frequency (yrs) = 100 Time interval (min) = 1 Drainage area (ac) = 8.360 Curve number (CN) = 70 Basin Slope (%)= See Worksheet Hydraulic length (ft)= See Worksheet Tc method = TR55 Time of conc. (min) = 16 Total precip. (in) = 2.27 Storm Distribution = Type II Storm duration (hrs) = 24 Shape factor = 484 Hydrograph Volume = 10,763 (cuft); 0.247 (acft) 0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (hrs) Runoff Hydrograph 100-yr frequency Runoff Hyd - Qp = 2.74 (cfs) Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Monday, Jan 10 2022 P-1 Hydrograph type = Rational Peak discharge (cfs) = 1.405 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 2.200 Runoff coeff. (C) = 0.3 Rainfall Inten (in/hr) = 2.129 Tc by TR55 (min) = 20 IDF Curve = SILT-IDF.IDF Rec limb factor = 1.00 Hydrograph Volume = 1,687 (cuft); 0.039 (acft) 0 5 10 15 20 25 30 35 40 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 1.41 (cfs) TR55 Tc Worksheet Hydraflow Express by Intelisolve Rational P-1 Description A B C Totals Sheet Flow Manning's n-value = 0.130 0.011 0.011 Flow length (ft) = 300.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 1.06 0.00 0.00 Land slope (%) = 10.33 0.00 0.00 Travel Time (min) = 18.96 + 0.00 + 0.00 = 18.96 Shallow Concentrated Flow Flow length (ft) = 294.00 0.00 0.00 Watercourse slope (%) = 31.30 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) = 9.03 0.00 0.00 Travel Time (min) = 0.54 + 0.00 + 0.00 = 0.54 Channel Flow X sectional flow area ((sqft)) = 2.50 0.00 0.00 Wetted perimeter ((ft)) = 5.39 0.00 0.00 Channel slope (%) = 4.10 0.00 0.00 Manning's n-value = 0.025 0.015 0.015 Velocity (ft/s) = 7.21 0.00 0.00 Flow length (ft) = 84.0 0.0 0.0 Travel Time (min) = 0.1941040.00+0 +0 =0.19 Total Travel Time, Tc .............................................................................. 20.00 min Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Monday, Jan 10 2022 P-2 Hydrograph type = Rational Peak discharge (cfs) = 2.400 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 3.130 Runoff coeff. (C) = 0.36 Rainfall Inten (in/hr) = 2.129 Tc by TR55 (min) = 20 IDF Curve = SILT-IDF.IDF Rec limb factor = 1.00 Hydrograph Volume = 2,879 (cuft); 0.066 (acft) 0 5 10 15 20 25 30 35 40 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (min) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 2.40 (cfs) TR55 Tc Worksheet Hydraflow Express by Intelisolve Rational P-2 Description A B C Totals Sheet Flow Manning's n-value = 0.130 0.011 0.011 Flow length (ft) = 300.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 1.06 0.00 0.00 Land slope (%) = 10.33 0.00 0.00 Travel Time (min) = 18.96 + 0.00 + 0.00 = 18.96 Shallow Concentrated Flow Flow length (ft) = 294.00 0.00 0.00 Watercourse slope (%) = 31.30 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) = 9.03 0.00 0.00 Travel Time (min) = 0.54 + 0.00 + 0.00 = 0.54 Channel Flow X sectional flow area ((sqft)) = 2.50 2.50 0.00 Wetted perimeter ((ft)) = 5.39 5.39 0.00 Channel slope (%) = 4.10 2.00 0.00 Manning's n-value = 0.025 0.025 0.015 Velocity (ft/s) = 7.21 5.04 0.00 Flow length (ft) = 84.0 154.0 0.0 Travel Time (min) = 0.1941040.00+ 0.50951020.00+0 =0.70 Total Travel Time, Tc .............................................................................. 20.00 min Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Monday, Jan 10 2022 P-3 Hydrograph type = Rational Peak discharge (cfs) = 0.741 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 0.900 Runoff coeff. (C) = 0.3 Rainfall Inten (in/hr) = 2.744 Tc by TR55 (min) = 13 IDF Curve = SILT-IDF.IDF Rec limb factor = 1.00 Hydrograph Volume = 578 (cuft); 0.013 (acft) 0 5 10 15 20 25 30 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) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 0.74 (cfs) TR55 Tc Worksheet Hydraflow Express by Intelisolve Rational P-3 Description A B C Totals Sheet Flow Manning's n-value = 0.130 0.011 0.011 Flow length (ft) = 300.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 1.06 0.00 0.00 Land slope (%) = 34.83 0.00 0.00 Travel Time (min) = 11.66 + 0.00 + 0.00 = 11.66 Shallow Concentrated Flow Flow length (ft) = 74.00 0.00 0.00 Watercourse slope (%) = 8.58 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) = 4.73 0.00 0.00 Travel Time (min) = 0.26 + 0.00 + 0.00 = 0.26 Channel Flow X sectional flow area ((sqft)) = 2.50 2.50 0.00 Wetted perimeter ((ft)) = 5.39 5.39 0.00 Channel slope (%) = 4.10 2.00 0.00 Manning's n-value = 0.025 0.025 0.015 Velocity (ft/s) = 7.21 5.04 0.00 Flow length (ft) = 84.0 154.0 0.0 Travel Time (min) = 0.1941040.00+ 0.50951020.00+0 =0.70 Total Travel Time, Tc .............................................................................. 13.00 min Hydrology Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jan 7 2022 PIPE P-4 Hydrograph type = Rational Peak discharge (cfs) = 2.635 Storm frequency (yrs) = 25 Time interval (min) = 1 Drainage area (ac) = 3.030 Runoff coeff. (C) = 0.33 Rainfall Inten (in/hr) = 2.636 Tc by TR55 (min) = 14 IDF Curve = SILT-IDF.IDF Rec limb factor = 1.00 Hydrograph Volume = 2,214 (cuft); 0.051 (acft) 0 5 10 15 20 25 30 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (min) Runoff Hydrograph 25-yr frequency Runoff Hyd - Qp = 2.64 (cfs) TR55 Tc Worksheet Hydraflow Express by Intelisolve Rational PIPE P-4 Description A B C Totals Sheet Flow Manning's n-value = 0.130 0.011 0.011 Flow length (ft) = 300.0 0.0 0.0 Two-year 24-hr precip. ((in)) = 1.06 0.00 0.00 Land slope (%) = 27.00 0.00 0.00 Travel Time (min) = 12.91 + 0.00 + 0.00 = 12.91 Shallow Concentrated Flow Flow length (ft) = 270.00 0.00 0.00 Watercourse slope (%) = 36.70 0.00 0.00 Surface description = Unpaved Paved Paved Average velocity (ft/s) = 9.77 0.00 0.00 Travel Time (min) = 0.46 + 0.00 + 0.00 = 0.46 Channel Flow X sectional flow area ((sqft)) = 2.50 0.00 0.00 Wetted perimeter ((ft)) = 5.39 0.00 0.00 Channel slope (%) = 6.44 0.00 0.00 Manning's n-value = 0.025 0.015 0.015 Velocity (ft/s) = 9.04 0.00 0.00 Flow length (ft) = 322.0 0.0 0.0 Travel Time (min) = 0.59369050.00+0 +0 =0.59 Total Travel Time, Tc .............................................................................. 14.00 min APPENDIX 6 HYDRAULIC COMPUTATIONS Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Monday, Jan 10 2022 P-1 Circular Diameter (ft) = 1.00 Invert Elev (ft) = 5684.03 Slope (%) = 1.00 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 1.41 Highlighted Depth (ft) = 0.42 Q (cfs) = 1.410 Area (sqft) = 0.32 Velocity (ft/s) = 4.47 Wetted Perim (ft) = 1.41 Crit Depth, Yc (ft) = 0.51 Top Width (ft) = 0.99 EGL (ft) = 0.73 0 1 2 3 Elev (ft)Depth (ft)Section 5683.50 -0.53 5684.00 -0.03 5684.50 0.47 5685.00 0.97 5685.50 1.47 5686.00 1.97 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Monday, Jan 10 2022 P-2 Circular Diameter (ft) = 1.00 Invert Elev (ft) = 5680.59 Slope (%) = 1.00 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 2.40 Highlighted Depth (ft) = 0.57 Q (cfs) = 2.400 Area (sqft) = 0.46 Velocity (ft/s) = 5.17 Wetted Perim (ft) = 1.71 Crit Depth, Yc (ft) = 0.67 Top Width (ft) = 0.99 EGL (ft) = 0.99 0 1 2 Elev (ft)Section 5680.00 5680.50 5681.00 5681.50 5682.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Monday, Jan 10 2022 P-3 Circular Diameter (ft) = 1.00 Invert Elev (ft) = 5689.59 Slope (%) = 1.00 N-Value = 0.025 Calculations Compute by: Known Q Known Q (cfs) = 0.74 Highlighted Depth (ft) = 0.44 Q (cfs) = 0.740 Area (sqft) = 0.34 Velocity (ft/s) = 2.21 Wetted Perim (ft) = 1.45 Crit Depth, Yc (ft) = 0.36 Top Width (ft) = 0.99 EGL (ft) = 0.52 0 1 2 Elev (ft)Section 5689.00 5689.50 5690.00 5690.50 5691.00 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Friday, Jan 7 2022 PIPE P-4 Circular Diameter (ft) = 1.00 Invert Elev (ft) = 5678.23 Slope (%) = 1.00 N-Value = 0.012 Calculations Compute by: Known Q Known Q (cfs) = 2.64 Highlighted Depth (ft) = 0.61 Q (cfs) = 2.640 Area (sqft) = 0.50 Velocity (ft/s) = 5.25 Wetted Perim (ft) = 1.79 Crit Depth, Yc (ft) = 0.70 Top Width (ft) = 0.97 EGL (ft) = 1.04 0 1 2 3 Elev (ft)Depth (ft)Section 5677.50 -0.73 5678.00 -0.23 5678.50 0.27 5679.00 0.77 5679.50 1.27 5680.00 1.77 Reach (ft) 1S PR-1 2P DETENTION POND Routing Diagram for 2211040_PR Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net, Printed 1/7/2022 HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link 2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 2HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 25-YR Type II 24-hr Default 24.00 1 1.79 2 2 100-YR Type II 24-hr Default 24.00 1 2.27 2 Type II 24-hr 25-YR Rainfall=1.79"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 3HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment 1S: PR-1 Runoff = 0.83 cfs @ 12.15 hrs, Volume= 0.096 af, Depth> 0.14" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=1.79" Area (ac) CN Description * 3.730 59 Sagebrush range, Fair/Poor, HSG B * 4.050 77 Sagebrush range, Fair/Poor, HSG D * 0.580 98 Impervious 8.360 70 Weighted Average 7.780 93.06% Pervious Area 0.580 6.94% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.9 300 0.2700 0.39 Sheet Flow, Range n= 0.130 P2= 1.06" 1.7 699 0.1890 7.00 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1.3 185 0.0214 2.36 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 15.9 1,184 Total Type II 24-hr 25-YR Rainfall=1.79"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 4HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Subcatchment 1S: PR-1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 25-YR Rainfall=1.79" Runoff Area=8.360 ac Runoff Volume=0.096 af Runoff Depth>0.14" Flow Length=1,184' Tc=15.9 min CN=70 0.83 cfs Type II 24-hr 25-YR Rainfall=1.79"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 5HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond 2P: DETENTION POND Inflow Area = 8.360 ac, 6.94% Impervious, Inflow Depth > 0.14" for 25-YR event Inflow = 0.83 cfs @ 12.15 hrs, Volume= 0.096 af Outflow = 0.42 cfs @ 12.43 hrs, Volume= 0.095 af, Atten= 50%, Lag= 16.9 min Primary = 0.42 cfs @ 12.43 hrs, Volume= 0.095 af Secondary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 5,665.66' @ 12.43 hrs Surf.Area= 504 sf Storage= 465 cf Plug-Flow detention time= 13.3 min calculated for 0.095 af (98% of inflow) Center-of-Mass det. time= 9.2 min ( 883.8 - 874.5 ) Volume Invert Avail.Storage Storage Description #1 5,664.50' 950 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 5,664.50 297 0 0 5,666.50 653 950 950 Device Routing Invert Outlet Devices #1 Primary 5,664.50'10.0" Round Culvert L= 9.5' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 5,664.50' / 5,664.40' S= 0.0105 '/' Cc= 0.900 n= 0.012, Flow Area= 0.55 sf #2 Device 1 5,664.50'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Device 1 5,665.75'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Secondary 5,666.00'2.0' long x 0.7' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 Coef. (English) 2.76 2.82 2.93 3.09 3.18 3.22 3.27 3.30 3.32 3.31 3.32 Primary OutFlow Max=0.42 cfs @ 12.43 hrs HW=5,665.66' (Free Discharge) 1=Culvert (Passes 0.42 cfs of 2.12 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.42 cfs @ 4.80 fps) 3=Orifice/Grate ( Controls 0.00 cfs) Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=5,664.50' (Free Discharge) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type II 24-hr 25-YR Rainfall=1.79"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 6HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Pond 2P: DETENTION POND Inflow Outflow Primary Secondary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=8.360 ac Peak Elev=5,665.66' Storage=465 cf 0.83 cfs 0.42 cfs0.42 cfs 0.00 cfs Type II 24-hr 100-YR Rainfall=2.27"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 7HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Subcatchment 1S: PR-1 Runoff = 2.68 cfs @ 12.12 hrs, Volume= 0.210 af, Depth> 0.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100-YR Rainfall=2.27" Area (ac) CN Description * 3.730 59 Sagebrush range, Fair/Poor, HSG B * 4.050 77 Sagebrush range, Fair/Poor, HSG D * 0.580 98 Impervious 8.360 70 Weighted Average 7.780 93.06% Pervious Area 0.580 6.94% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.9 300 0.2700 0.39 Sheet Flow, Range n= 0.130 P2= 1.06" 1.7 699 0.1890 7.00 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1.3 185 0.0214 2.36 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 15.9 1,184 Total Type II 24-hr 100-YR Rainfall=2.27"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 8HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Subcatchment 1S: PR-1 Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Type II 24-hr 100-YR Rainfall=2.27" Runoff Area=8.360 ac Runoff Volume=0.210 af Runoff Depth>0.30" Flow Length=1,184' Tc=15.9 min CN=70 2.68 cfs Type II 24-hr 100-YR Rainfall=2.27"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 9HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Summary for Pond 2P: DETENTION POND Inflow Area = 8.360 ac, 6.94% Impervious, Inflow Depth > 0.30" for 100-YR event Inflow = 2.68 cfs @ 12.12 hrs, Volume= 0.210 af Outflow = 2.57 cfs @ 12.16 hrs, Volume= 0.208 af, Atten= 4%, Lag= 2.7 min Primary = 2.20 cfs @ 12.16 hrs, Volume= 0.205 af Secondary = 0.36 cfs @ 12.16 hrs, Volume= 0.003 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 5,666.16' @ 12.16 hrs Surf.Area= 593 sf Storage= 741 cf Plug-Flow detention time= 11.4 min calculated for 0.208 af (99% of inflow) Center-of-Mass det. time= 8.6 min ( 857.2 - 848.6 ) Volume Invert Avail.Storage Storage Description #1 5,664.50' 950 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 5,664.50 297 0 0 5,666.50 653 950 950 Device Routing Invert Outlet Devices #1 Primary 5,664.50'10.0" Round Culvert L= 9.5' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 5,664.50' / 5,664.40' S= 0.0105 '/' Cc= 0.900 n= 0.012, Flow Area= 0.55 sf #2 Device 1 5,664.50'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Device 1 5,665.75'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Secondary 5,666.00'2.0' long x 0.7' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 Coef. (English) 2.76 2.82 2.93 3.09 3.18 3.22 3.27 3.30 3.32 3.31 3.32 Primary OutFlow Max=2.18 cfs @ 12.16 hrs HW=5,666.15' (Free Discharge) 1=Culvert (Passes 2.18 cfs of 2.92 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.51 cfs @ 5.87 fps) 3=Orifice/Grate (Orifice Controls 1.66 cfs @ 3.05 fps) Secondary OutFlow Max=0.33 cfs @ 12.16 hrs HW=5,666.15' (Free Discharge) 4=Broad-Crested Rectangular Weir (Weir Controls 0.33 cfs @ 1.08 fps) Type II 24-hr 100-YR Rainfall=2.27"2211040_PR Printed 1/7/2022Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net Page 10HydroCAD® 10.10-4b Sampler s/n S11218 © 2020 HydroCAD Software Solutions LLC This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and educational use ONLY. For actual design or modeling applications you MUST use a full version of HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical support,training materials, and additional features which are essential for actual design work. Pond 2P: DETENTION POND Inflow Outflow Primary Secondary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)3 2 1 0 Inflow Area=8.360 ac Peak Elev=5,666.16' Storage=741 cf 2.68 cfs 2.57 cfs 2.20 cfs 0.36 cfs