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Home My WebLink AboutELIZABETH STREET FARMS - FDP - FDP170037 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTFINAL DRAINAGE REPORT Elizabeth Street Farms Fort Collins, Colorado Prepared for: High Plains Builders, LLC P.O. Box 2796 Gillette, Wyoming 82717 Phone: (307) 257-2352 Prepared by: Galloway & Company, Inc. 5265 Ronald Reagan Blvd., Suite 210 Johnstown, Colorado 80534 Phone: (970) 800-3300 Contact: Herman Feissner, PE Original Preparation: November 2nd, 2016 Revised: July 12th, 2017 Revised: September 12th, 2017 Revised: December 27th, 2017 1 TABLE OF CONTENTS TABLE OF CONTENTS.......................................................................................................................... 1 I. CERTIFICATIONS .......................................................................................................................... 2 II. GENERAL LOCATION AND DESCRIPTION .................................................................................. 3 III. DRAINAGE BASINS AND SUB-BASINS ........................................................................................ 5 IV. DRAINAGE DESIGN CRITERIA ..................................................................................................... 5 V. DRAINAGE FACILITY DESIGN .................................................................................................... 10 VI. EROSION AND SEDIMENT CONTROL MEASURES ................................................................... 13 VII. CONCLUSIONS ............................................................................................................................ 14 VIII. REFERENCES .............................................................................................................................. 15 APPENDIX A - REFERENCE MATERIALS VICINITY MAP NRCS SOILS MAP FEMA FIRMETTE CITY OF FORT COLLINS FLOOD MAPPING APPENDIX B - HYDROLOGY CALCULATIONS EXISTING RUNOFF CALCULATIONS PROPOSED RUNOFF CALCULATIONS APPENDIX C - HYDRAULIC CALCULATIONS SWALE CAPACITY CALCULATIONS DETENTION POND SIZING APPENDIX D – DRAINAGE MAPS + VARIANCE APPLICATION EXISTING CONDITION DRAINAGE MAP WEST PLUM PUD DEVELOPED CONDITION DRAINAGE MAP 2 I. CERTIFICATIONS CERTIFICATION OF ENGINEER “I hereby certify that this report for the final drainage design of Elizabeth Street Farms was prepared by me (or under my direct supervision) in accordance with the provisions of the Fort Collins Stormwater Criteria Manual for the owners thereof.” ______________________________________ Herman Feissner, PE Registered Professional Engineer State of Colorado No. 38066 For and on behalf of Galloway & Company, Inc. CERTIFICATION OF OWNER “High Plains Builders, LLC hereby certifies that the drainage facilities for the Elizabeth Street Farms be constructed according to the design presented in this report. We understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed and/or certified by our engineer. We also understand that the City of Fort Collins relies on the representation of others to establish that drainage facilities are designed and constructed in compliance with City of Fort Collins guidelines, standards, or specifications. Review by the City of Fort Collins can therefore in no way limit or diminish any liability, which we or any other party may have with respect to the design or construction of such facilities.” ____________________________________ High Plains Builders, LLC Attest: ___________________________________ (Name of Responsible Party) __________________________________ Notary Public Authorized Signature STAMP AND SIGNATURE WITH APPROVAL OF FINAL DRAINAGE REPORT ` 3 II. GENERAL LOCATION AND DESCRIPTION LOCATION Elizabeth Street Farms (hereafter referred to as “the site” or “project site”) is located at 2620 West Elizabeth Street. The site is bounded on north by single-family residential development and Pear Street right-of-way (existing cul-de-sac); on the south by West Elizabeth Street; and on the east and west by single-family residential. More specifically, the site is Tract A of West Plum Street – a Planned Unit Development situate in the north half of Section 16, Township 7 north, Range 69 west of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. Refer to Appendix A for a vicinity map. DESCRIPTION OF PROPERTY The project site consists of ±2.56 acres. It is largely vacant and undeveloped. Previously the site was used for agriculture. An existing two-story brick house, which the developer plans to restore, is located in the southeast region of the site. An existing irrigation lateral, which is still in use, crosses the site from west to east. The existing grades average between 0.50% and 1.00%. Locally steeper grades exist along the irrigation lateral and around the existing house. The existing runoff flows from northwest to southeast. An existing swale along the north edge of West Elizabeth Street captures existing runoff and conveys it east. There are no major drainage ways passing through the project site. According to the USDA NRCS Web Soil Survey, ‘Altvan-Satanta loams, 0 to 3 percent slopes’ covers roughly one-third of the project site. The remaining two-thirds of the site are ‘Altvan- Satanta loams, 3 to 9 percent slopes’. These soils are associated with Hydrologic Soil Group (HSG) ‘B’. HSG ‘B’ soils have 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. Refer to Appendix A for additional soils information. Hollingsworth Associates, Inc. conducted a subsurface study the project site. The results of the preliminary geotechnical investigation are summarized in Subsurface Study for Ten Lots West Elizabeth Subdivision Fort Collins, Colorado (Job No.: 16-469 | Dated: October 12, 2016). The ` 4 subsurface conditions across the lots were quite uniform, as indicated by exploratory borings B-1 through B-5, and consisted of 12 inches of topsoil, 2 to 11 feet of medium stiff to stiff sandy clay, which occasionally graded into clayey sand, and 2 feet to 5 feet of firm to medium hard, interlayered and integrated weathered claystone/sandstone overlaying hard to very hard claystone for the depth drilled, 21 feet. The site is situated east of the Pleasant Valley and Lake Canal. An operational west-to-east irrigation lateral flows across the project site. According to the ditch rider, Ed Wendel, five people currently receive water from the lateral. Elizabeth Street Farms will develop in a single phase as single-family residential. The project includes the development of eight (8) single-family lots, street improvements, wet and dry utility infrastructure and landscaping. A single point of access will be provided to the project site from Pear Street. ` 5 III. DRAINAGE BASINS AND SUB-BASINS MAJOR BASIN DESCRIPTION The project site is located in the Canal Importation master plan drainage basin. According to the City of Fort Collins website (www.fcgov.com), this basin “spans nearly five square miles in west- central Fort Collins. Three major irrigation canals traverse the basin from north to south and impact the drainage in the basin. The canals can intercept runoff traveling through the basin and transport it out of the basin, and they also spill runoff into the basin when their capacity is exceeded”. SUB- BASIN DESCRIPTION The project site generally conforms to the input parameters of SWMM subbasin 9 in the Canal Importation drainage basin. SWMM subbasin 9 is 60% impervious. It generally drains to Elizabeth Street and then east. The proposed site will be ±56% impervious. The runoff ultimately drains into the Red Fox Meadows neighborhood natural area. The project site is shown on FEMA Map Numbers 08069C0960F and 08069C0978G (refer to Appendix A for FEMA Firmettes). Neither map shows the project impacted by an existing floodplain/floodway. Refer to Appendix A for a copy of each Firmette and a copy of the City of Fort Collins flood map. ` 6 IV. DRAINAGE DESIGN CRITERIA REGULATIONS The final drainage design presented herein was prepared in accordance with the Fort Collins Amendments to the Urban Drainage and Flood Control District Criteria Manual (i.e., Urban Drainage and Flood Control District Urban Storm Drainage Criteria Manuals Volumes 1, 2 and 3 [Manual]). Together, the requirements are referred to as the Fort Collins Stormwater Criteria Manual [FCSCM]. DIRECTLY CONNECTED IMPERVIOUS AREA (DCIA) The project site is encumbered by several constraints; therefore, we developed a strategy for implementing ‘The Four-Step Process’ for stormwater quality management to the Maximum Extent Practicable (MEP). Each step is listed below along with a brief narrative describing the implementation strategy. Step 1 - Employ runoff reduction practices The developed runoff from basins A1 through A4 flow through vegetated swales before entering the on-site detention facility. The UDFCD defines a Grass Swale as “Densely vegetated drainage way with low-pitched side slopes that collects and slowly conveys runoff. The design of the longitudinal slope and cross-section size forces the flow to be slow and shallow, thereby facilitating sedimentation while limiting erosion.” The proposed vegetated swales will have low longitudinal slopes of ±0.50%. It is designed to convey 2-year storm event runoff in a slow (i.e., <1 ft/sec) and shallow manner (i.e., normal depth <1 foot). This design encourages settling and infiltration. Approximately 1.2 acres of new impervious area will be created by the project. Of this, ±0.88 acre (73 percent) will be treated by the vegetated swales. Impervious areas have been disconnected to the Maximum Extent Practicable. (MEP) Step 2 - Implement BMPs that provide a Water Quality Capture Volume (WQCV) The proposed BMPs do not provide WQCV because of site constraints. Refer to DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS for additional information. ` 7 Step 3 - Stabilize drainageways Planting within the vegetated swales will stabilize the drainage way and prevent erosion during storm events exceeding the 2-year recurrence level. Step 4 - Implement site specific and other source control BMPS Site specific considerations such as material storage and other site operations are addressed in the Stormwater Management Plan (SWMP). DEVELOPMENT CRITERIA REFERENCE AND CONSTRAINTS Several constraints drove the WQ/LID and detention pond design presented here. · The outfall from the proposed on-site detention pond is the flowline of West Elizabeth Street, elevation ±5107.41. · The developer wants to keep the existing house; this constrains the grading design. · The closest storm drain system is located more than one-half mile east along Elizabeth Street. · The site is generally flat. The existing grades average 0.50% to 1.00%. Locally steeper grades exist around the structures and existing irrigation lateral. · The project site is bounded by existing development. · The existing soils are unsuitable for infiltrating stormwater runoff. The boring logs show clay underlain by claystone/sandstone and claystone. Considering the expansive nature of the subgrade soils, the subsurface study recommended that residences be founded on drilled piers (refer to Appendix A for these boring logs). Appendix D contains a Stormwater Alternative Compliance/Variance Application. This document references a short list of ‘hardships’ preventing the site from meeting the requirements presented in ORDINANCE NO. 007 | 3.1 Low Impact Development criteria. HYDROLOGICAL CRITERIA For urban catchments that are not complex and are generally 160 acres or less in size, it is acceptable that the design storm runoff be analyzed using the Rational Method. The Rational Method is often used when only the peak flow rate or total volume of runoff is needed (e.g., ` 8 storm sewer sizing or simple detention basin sizing). The Rational Method was used to estimate the peak flow at each design point. Routing calculations (i.e., time attenuation) that aggregate the basins draining to a specific design point are include in the Rational Method calculations in Appendix B. The Rational Method is based on the Rational Formula: Q = CiA Where: Q = the maximum rate of runoff, cfs C = a runoff coefficient that is the ratio between the runoff volume from an area and the average rate of rainfall depth over a given duration for that area i = average intensity of rainfall in inches per hour for a duration equal to the Time of Concentration (Tc) A = area, acres The one-hour rainfall Intensity-Duration-Frequency tables for use with the Rational Method of runoff analysis is provided in Appendix B. The 2-year and 100-year storm events serve as the basis for the drainage system design. The 2-year storm is considered the minor storm event. It has a fifty percent probability of exceedance during any given year. The 100-year storm is considered the major storm event. It has a one percent probability of exceedance during any given year. The 2-year drainage system, at a minimum, must be designed to transport runoff from the 2- year recurrence interval storm event with minimal disruption to the urban environment. The 100-year drainage system, at a minimum, must be designed to convey runoff from the 100- year recurrence interval flood to minimize life hazards and health, damage to structures, and interruption to traffic and services. HYDRAULIC CRITERIA Street Capacity Analysis ` 9 The street section generally drains from the crown, across the travel lane and into roadside swales. The proposed street section is bounded by a one foot wide concrete ribbon along each side of the asphalt. Storm Drain and Swale Capacity Analysis The storm drain system is limited to short culverts and swales that convey runoff underneath driveways and along the internal streets. The hydraulic analysis was completed using Bentley FlowMaster. Refer to Appendix C for swale and culvert capacity calculations. ` 10 V. DRAINAGE FACILITY DESIGN GENERAL CONCEPT This final design presents a system for collecting and conveying developed runoff from the proposed development at Elizabeth Street Farms to the on-site detention pond. The on-site developed runoff in each catchment begins as overland flow from the residential lot areas (i.e., roof area, concrete hardscape and landscaping). This runoff then flows from the lots to the swale sections along the backs and fronts of the lots. These swales drain into on- site detention pond (i.e., basin A5). SPECIFIC DETAILS On-Site Detention Pond The proposed on-site detention pond was sized with the Modified FAA Method (refer to Appendix C). The site constraints limited the volume of the on-site detention pond to 9385 ft3 (0.22 ac-ft). The proposed release rate from the detention pond is 1.2 cfs. This exceeds the calculated 2-year release rate of ±0.6 cfs (combined release from basins EX4 and EX5). There does not appear to be any remaining areas that can develop in SWMM subbasin 9, except for this site, and the site is located at the far west end of the basin. Considering this, the proposed increase in release rate will have a negligible effect on the basin during the 100-year storm event. The pond will discharge to the flowline in West Elizabeth Street. A Basins These basins comprise approximately 1.84 acres. The developed runoff from the roof areas will flow overland through landscaping and into vegetated swales along the private internal streets. Flow in the swales will drain into the on-site detention pond. Basin A1 will flow into the on-site detention pond through two (2) - 8” HDPE culverts. We proposed medium duty flapgates at the downstream end to prevent ponded water in basin A5 from draining back into basin A1. B Basin This basin is comprised of private street improvements and portions of two lots. The developed runoff from the structures will be disconnected from the street section by landscaped area. The ` 11 undetained developed runoff, Q2=0.40 cfs and Q100=2.4 cfs, will drain into Pear Street and then flow north ±235 lf, in the existing roll over curb and gutter, to an existing concrete cross pan. The cross pan conveys local developed runoff from West Plum Street PUD basin 2 (±2.75 acres, Q2=3.09 cfs, Q100=8.97 cfs) to the east in an existing swale with a concrete pan and into an existing detention pond. View of existing swale looking east from Pear Street We approximated the original swale design in FlowMaster. Without accounting for the effects of Tc, we added basin B1 runoff to the proposed swale design (Q100=5.09 cfs). The normal depth increased from 0.50 foot to 0.58 foot. The proposed flows should have a negligible impact on the existing drainage infrastructure in this area. We do recommend clearing vegetation from underneath the fence situated perpendicular to the swale and at the point the swale drains into the existing detention pond (see photograph below). ` 12 Existing swale looking west at existing detention pond OS1 Basin This basin includes future West Elizabeth Street right-of-way and existing West Elizabeth Street improvements. The runoff will continue to flow east along Elizabeth Street. ` 13 VI. EROSION AND SEDIMENT CONTROL MEASURES A General Permit for Stormwater Discharge Associated with Construction Activities issued by the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division (WQCD), will be acquired for the site. A Stormwater Management Plan (SWMP) was prepared and is presented separately. It identifies the Best Management Practices (BMPs) which, when implemented, will meet the requirements of the General Permit. ` 14 VII. CONCLUSIONS COMPLIANCE WITH STANDARDS The design presented in this final drainage report for Elizabeth Street Farms has been prepared in accordance with the design standards and guidelines presented in the Fort Collins Stormwater Criteria Manual. VARIANCES A Stormwater Alternative Compliance/Variance Application is included in Appendix D. The site seeks a variance from meeting the requirements presented in ORDINANCE NO. 007 | 3.1 Low Impact Development criteria. DRAINAGE CONCEPT The proposed Elizabeth Street Farms storm drainage improvements should provide adequate protection for the developed site. The proposed drainage design for the site should not negatively impact the existing downstream storm drainage system. ` 15 VII. REFERENCES 1. Fort Collins Stormwater Criteria Manual (Addendum to the Urban Storm Drainage Criteria Manuals Volumes 1, 2 and 3), prepared by City of Fort Collins. 2. Urban Drainage and Flood Control District, Drainage Criteria Manual Volumes 1 and 2, prepared by Wright-McLaughlin Engineers, dated June 2001 (revised April 2008), and the Volume 3, prepared by Wright-McLaughlin Engineers, dated September 1992 and revised November 2010. ` APPENDIX A REFERENCE MATERIAL ` VICINITY MAP Vicinity Map Not to Scale West Elizabeth Street Rocky Road Project Site Overland Trail Timber Lane Pearl Street Orchard Place ` NRCS SOILS MAP Hydrologic Soil Group—Larimer County Area, Colorado (2620 West Elizabeth Street) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/25/2016 Page 1 of 4 4491570 4491580 4491590 4491600 4491610 4491620 4491630 4491640 4491650 4491660 4491670 4491570 4491580 4491590 4491600 4491610 4491620 4491630 4491640 4491650 4491660 4491670 489340 489350 489360 489370 489380 489390 489400 489410 489420 489430 489440 489450 489460 489470 489480 489490 489340 489350 489360 489370 489380 489390 489400 489410 489420 489430 489440 489450 489460 489470 489480 489490 40° 34' 32'' N 105° 7' 33'' W 40° 34' 32'' N 105° 7' 26'' W 40° 34' 29'' N 105° 7' 33'' W 40° 34' 29'' N 105° 7' 26'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 35 70 140 210 Feet 0 10 20 40 60 Meters Map Scale: 1:765 if printed on A landscape (11" x 8.5") sheet. Warning: 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: http://websoilsurvey.nrcs.usda.gov 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: Larimer County Area, Colorado Hydrologic Soil Group Hydrologic Soil Group— Summary by Map Unit — Larimer County Area, Colorado (CO644) Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes B 0.8 31.6% 4 Altvan-Satanta loams, 3 to 9 percent slopes B 1.7 68.4% Totals for Area of Interest 2.6 100.0% 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. Rating Options Aggregation Method: Dominant Condition Hydrologic Soil Group—Larimer County Area, Colorado 2620 West Elizabeth Street Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/25/2016 Page 3 of 4 Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado 2620 West Elizabeth Street Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/25/2016 Page 4 of 4 ` FEMA FIRMETTE ` CITY OF FORT COLLINS FLOOD MAPPING 1,128 188.0 2620 West Elizabeth Street Fort Collins, Colorado This map is a user generated static output from the City of Fort Collins FCMaps Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. City of Fort Collins - GIS 143.0 1: WGS_1984_Web_Mercator_Auxiliary_Sphere 0 71.50 143.0 Feet Notes Legend 857 FEMA Floodplain FEMA High Risk - Floodway FEMA High Risk - 100 Year FEMA Moderate Risk - 100 / 500 Year FEMA Map Panel City Floodplains City High Risk - Floodway City High Risk - 100 Year City Moderate Risk - 100 Year City Limits ` APPENDIX B HYDROLOGY CALCULATIONS ` EXISTING RUNOFF CALCULATIONS Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street Location: CO, Fort Collins Project No.: Calculated By: H. Feissner Checked By: H. Feissner INPUT User Input Date: 11/1/16 INPUT User Input Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family 95% 5% 62.5% 70% 75% 80% EX1 0.05 50 0.00 0 20 0.05 20 95 0.00 0 0.20 EX2 0.10 50 0.00 0 20 0.0998235 20 95 0.00 0 0.20 EX3 0.18 50 0.00 0 20 0.1802596 20 95 0.00 0 0.20 EX4 0.76 50 0.05 3 20 0.6972378 18 95 0.01 1 0.23 EX5 1.26 50 0.00 0 20 1.2228005 19 95 0.04 3 0.22 Σ Basins 2.35 COMPOSITE RUNOFF COEFFICIENTS Area (ac) Area Weighted Gravel (e.g., driveway) Undeveloped, Heavy Soil: Flat <2% Area Weighted Runoff Coefficient Area (ac) HPB01.01 Area Weighted C2 Basin ID Total Area (ac) Runoff Coefficient Area (ac) Existing Roof and Concrete (e.g., slab) Runoff Coefficient Page 1 of 1 11/1/2016 Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street Location: CO, Fort Collins Project No.: Calculated By: H. Feissner Checked By: H. Feissner Date: 11/1/16 1 2 3 4 5 6 7 8 9 10 13 14 16 17 18 19 20 21 22 23 24 BASIN D.A. Hydrologic C2 C 5 C100 U.S. D.S. L Calculated S Ti | 2-Year T i | 100-Year L Calculated Cv VEL. Tt COMP. T c | 2-Year COMP. Tc | 100-Year TOTAL Urbanized Tc T c | 2-Year Tc | 100-Year ID (AC) Soils Group Cf=1.00 C f=1.00 Cf =1.25 (FT) Slope, % (%) (MIN) (MIN) (FT) Slope, % (FPS) (MIN) (MIN) (MIN) LENGTH(FT) (MIN) (MIN) (MIN) EX1 0.05 C 0.20 0.20 0.25 12.26 10.94 10 13.20 2.00 2.3 2.1 0 0.00 15 0.0 0.0 2.3 2.1 10 10.1 5.0 5.0 EX2 0.10 C 0.20 0.20 0.25 9.14 7.84 50 2.60 2.00 8.7 8.2 0 0.00 15 0.0 0.0 8.7 8.2 50 10.3 8.7 8.2 EX3 0.18 C 0.20 0.20 0.25 12.19 10.83 10 13.60 2.00 2.2 2.1 0 0.00 15 0.0 0.0 2.2 2.1 10 10.1 5.0 5.0 EX4 0.76 C 0.23 0.23 0.29 11.30 7.84 304 1.14 2.00 27.1 25.3 0 0.00 15 0.0 0.0 27.1 25.3 304 11.7 27.1 25.3 EX5 1.26 C 0.22 0.22 0.28 12.56 9.14 342 1.00 2.00 30.4 28.5 0 0.00 15 0.0 0.0 30.4 28.5 342 11.9 30.4 28.5 NOTES: Ti = (1.87*(1.1 - CC f)*(L)^0.5)/((S)^0.33), S in % Cv Tt=L/60V (Velocity From Fig. 501) 2.5 Velocity V=Cv*S^0.5, S in ft/ft 5 Tc Check = 10+L/180 7 For Urbanized basins a minimum Tc of 5.0 minutes is required. 10 For non-urbanized basins a minimum Tc of 10.0 minutes is required 15 20 FG Elevations Paved Areas and Shallow Paved Swales DATA Type of Land Surface Heavy Meadow Tillage/Field Short Pasture and Lawns Nearly Bare Ground Grassed Waterway INITIAL/OVERLAND FINAL (Ti) TRAVEL TIME (Tt) (URBANIZED BASINS) STANDARD FORM SF-2 TIME OF CONCENTRATION SUB-BASIN Tc CHECK HPB01.01 Page 1 of 1 11/1/2016 Project Name: 2620 West Elizabeth Street Subdivision: Elizabeth Street Farms Project No.: HPB01.01 Location: CO, Fort Collins Calculated By: H. Feissner Design Storm: Checked By: H. Feissner Date: TRAVEL TIME STREET Design Point Basin ID Area (Ac) Runoff Coeff. | C 2 Tc | 2-Year (min) C*A (Ac) I (in/hr) Q (cfs) Tc (min) C*A (Ac) I (in/hr) Q (cfs) Slope (%) Street Flow (cfs) Design Flow (cfs) Slope (%) Pipe Size (inches) Length (ft) Velocity (fps) Tt (min) REMARKS EX1 EX1 0.05 0.20 5.0 0.01 2.86 0.0 EX2 EX2 0.10 0.20 8.7 0.02 2.39 0.0 EX3 EX3 0.18 0.20 5.0 0.04 2.86 0.1 EX4 EX4 0.76 0.23 27.1 0.18 1.36 0.2 EX5 EX5 1.26 0.22 30.4 0.28 1.27 0.4 DIRECT RUNOFF TOTAL RUNOFF STREET PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) 2-Year 11/1/16 Page 1 of 1 11/1/2016 STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) Project Name: 2620 West Elizabeth Street Subdivision: Elizabeth Street Farms Project No.: HPB01.01 Location: CO, Fort Collins Calculated By: H. Feissner Design Storm: Checked By: H. Feissner Date: TRAVEL TIME STREET Design Point Basin ID Area (Ac) Runoff Coeff. | C 100 Tc | 100-Year (min) C*A (Ac) I (in/hr) Q (cfs) Tc (min) C*A (Ac) I (in/hr) Q (cfs) Slope (%) Street Flow (cfs) Design Flow (cfs) Slope (%) Pipe Size (inches) Length (ft) Velocity (fps) Tt (min) REMARKS EX1 EX1 0.05 0.25 5.0 0.01 9.98 0.1 EX2 EX2 0.10 0.25 8.2 0.02 8.52 0.2 EX3 EX3 0.18 0.25 5.0 0.05 9.98 0.4 EX4 EX4 0.76 0.29 25.3 0.22 4.93 1.1 EX5 EX5 1.26 0.28 28.5 0.35 4.59 1.6 100-Year DIRECT RUNOFF TOTAL RUNOFF STREET 11/1/16 PIPE Page 1 of 1 11/1/2016 ` PROPOSED RUNOFF CALCULATIONS 41 Table RO-11 Rational Method Runoff Coefficients for Composite Analysis Character of Surface Runoff Coefficient Streets, Parking Lots, Drives: Asphalt 0.95 Concrete 0.95 Gravel 0.5 Roofs 0.95 Recycled Asphalt 0.8 Lawns, Sandy Soil: Flat <2% 0.1 Average 2 to 7% 0.15 Steep >7% 0.2 Lawns, Heavy Soil: Flat <2% 0.2 Average 2 to 7% 0.25 Steep >7% 0.35 (4) A new Section 2.9 is added, to read as follows: 2.9 Composite Runoff Coefficient Drainage sub-basins are frequently composed of land that has multiple surfaces or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: ( ) t n i i i A C A C ∑ = = 1 * (RO-8) Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (Ai) Ai = Area of Surface with Runoff Coefficient of Ci, acres or feet2 n = Number of different surfaces to be considered At = Total Area over which C is applicable, acres or feet2 (5) A new Section 2.10 is added, to read as follows: 42 2.10 Runoff Coefficient Adjustment for Infrequent Storms The runoff coefficients provided in tables RO-10 and RO-11 are appropriate for use with the 2-year storm event. For storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapo-transpiration and other losses that have a proportionally smaller effect on storm runoff. This adjustment is applied to the composite runoff coefficient. These frequency adjustment factors are found in Table RO-12. Table RO-12 Rational Method Runoff Coefficients for Composite Analysis Storm Return Period (years) Frequency Factor Cf 2 to 10 11 to 25 26 to 50 51 to 100 1.00 1.10 1.20 1.25 Note: The product of C times Cf cannot exceed the value of 1, in the cases where it does a value of 1 must be used (6) Section 3.1 is deleted in its entirety. (7) Section 3.2 is deleted in its entirety. (8) Section 3.3 is deleted in its entirety. (9) A new Section 4.3 is added, to read as follows: 4.3 Computer Modeling Practices (a) For circumstances requiring computer modeling, the design storm hydrographs must be determined using the Stormwater Management Model (SWMM). Basin and conveyance element parameters must be computed based on the physical characteristics of the site. (b) Refer to the SWMM Users’ Manual for appropriate modeling methodology, practices and development. The Users’ Manual can be found on the Environmental Protection Agency (EPA) website (http://www.epa.gov/ednnrmrl/models/swmm/index.htm). (c) It is the responsibility of the design engineer to verify that all of the models used in the design meet all current City criteria and regulations. 4.3.1 Surface Storage, Resistance Factors, and Infiltration Table RO-13 provides values for surface storage for pervious and impervious surfaces and the infiltration rates to be used with SWMM. Table RO-13 also lists the appropriate infiltration decay rate, zero detention depth and resistance factors, or Manning’s “n” values, for pervious and impervious surfaces to be used for SWMM modeling in the city of Fort Collins. Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street Location: CO, Fort Collins Project No.: Calculated By: H. Feissner Checked By: H. Feissner INPUT User Input Date: 12/26/17 INPUT User Input Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family 95% 5% 60% 70% 75% 80% A1 0.16 95 0.00 0 20 0.00 0 60 0.16 60 0.60 A2 0.39 95 0.11 27 20 0.03 2 60 0.24 38 0.66 A3 0.48 95 0.12 24 20 0.04 1 60 0.32 40 0.66 A4 0.41 95 0.01 2 20 0.06 3 60 0.35 50 0.55 A5 0.40 95 0.07 16 20 0.26 13 60 0.07 11 0.40 B1 0.28 95 0.07 25 20 0.01 1 60 0.19 41 0.67 OS1 0.44 95 0.35 76 20 0.09 4 60 0.00 0 0.80 Σ Basins 2.56 ΣDetention Pond Tributary Area 1.84 COMPOSITE RUNOFF COEFFICIENTS Area (ac) Area Weighted Asphalt + Concrete Walks Lawns, Heavy Soil: Flat <2% Area Weighted Runoff Coefficient Area (ac) HPB01.01 Area Weighted C2 Basin ID Total Area (ac) Runoff Coefficient Area (ac) Lots (e.g., Single-Family, Alley Loaded) Runoff Coefficient Page 1 of 1 12/26/2017 Subdivision: Elizabeth Street Farms Project Name: 2620 West Elizabeth Street Location: CO, Fort Collins Project No.: Calculated By: H. Feissner Checked By: H. Feissner Date: 12/26/17 1 2 3 4 5 6 7 8 9 10 13 14 16 17 18 19 20 21 22 23 24 BASIN D.A. Hydrologic C2 C 5 C100 L S Ti | 2-Year T i | 100-Year L Calculated Cv VEL. Tt COMP. T c | 2-Year COMP. Tc | 100-Year TOTAL Urbanized Tc T c | 2-Year Tc | 100-Year ID (AC) Soils Group Cf=1.00 C f=1.00 Cf =1.25 (FT) (%) (MIN) (MIN) (FT) Slope, % (FPS) (MIN) (MIN) (MIN) LENGTH(FT) (MIN) (MIN) (MIN) A1 0.16 C 0.60 0.60 0.75 50 2.00 5.2 3.7 102 0.78 15 1.3 1.3 6.5 5.0 152 10.8 6.5 5.0 A2 0.39 C 0.66 0.66 0.83 63 2.00 5.1 3.2 205 0.66 15 1.2 2.8 7.9 6.0 268 11.5 7.9 6.0 A3 0.48 C 0.66 0.66 0.82 102 2.00 6.6 4.2 226 0.51 15 1.1 3.5 10.1 7.7 328 11.8 10.1 7.7 A4 0.41 C 0.55 0.55 0.69 52 2.00 5.9 4.4 247 0.74 15 1.3 3.2 9.1 7.6 299 11.7 9.1 7.6 A5 0.40 C 0.40 0.40 0.49 59 2.00 8.0 6.9 256 0.92 15 1.4 3.0 11.0 9.9 315 11.8 11.0 9.9 B1 0.28 C 0.67 0.67 0.84 130 2.00 7.2 4.3 0 20 0.0 0.0 7.2 4.3 130 10.7 7.2 5.0 OS1 0.44 C 0.80 0.80 1.00 28 2.00 2.4 0.8 392 1.00 20 2.0 3.3 5.6 4.1 420 12.3 5.6 5.0 NOTES: Ti = (1.87*(1.1 - CC f)*(L)^0.5)/((S)^0.33), S in % Cv Tt=L/60V (Velocity From Fig. 501) 2.5 Velocity V=Cv*S^0.5, S in ft/ft 5 Tc Check = 10+L/180 7 For Urbanized basins a minimum Tc of 5.0 minutes is required. 10 For non-urbanized basins a minimum Tc of 10.0 minutes is required 15 Paved Areas and Shallow Paved Swales 20 DATA Type of Land Surface Heavy Meadow Tillage/Field Short Pasture and Lawns Nearly Bare Ground Grassed Waterway INITIAL/OVERLAND FINAL (Ti) TRAVEL TIME (Tt) (URBANIZED BASINS) STANDARD FORM SF-2 TIME OF CONCENTRATION SUB-BASIN Tc CHECK HPB01.01 Page 1 of 1 12/26/2017 36 RAINFALL INTENSITY-DURATION-FREQUENCY CURVE 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 0.00 10.00 20.00 30.00 40.00 50.00 60.00 STORM DURATION (minutes) RAINFALL INTENSITY (inches/hour) 2-Year Storm 10-Year Storm 100-Year Storm Figure RA-16 City of Fort Collins Rainfall Intensity-Duration-Frequency Curves (13) Section 5.0 is deleted in its entirety. (14) Section 6.0 is deleted in its entirety. (15) Section 7.0 is deleted in its entirety. (16) Section 7.1 is deleted in its entirety. (17) Section 7.2 is deleted in its entirety. (18) Section 7.3 is deleted in its entirety. (19) Section 8.0 is deleted in its entirety. (20) Table RA-1 is deleted in its entirety. Project Name: 2620 West Elizabeth Street Subdivision: Elizabeth Street Farms Project No.: HPB01.01 Location: CO, Fort Collins Calculated By: H. Feissner Design Storm: Checked By: H. Feissner Date: TRAVEL TIME STREET Design Point Basin ID Area (Ac) Runoff Coeff. | C 2 Tc | 2-Year (min) C*A (Ac) I (in/hr) Q (cfs) Tc (min) C*A (Ac) I (in/hr) Q (cfs) Slope (%) Street Flow (cfs) Design Flow (cfs) Slope (%) Pipe Size (inches) Length (ft) Velocity (fps) Tt (min) REMARKS A1 A1 0.16 0.60 6.5 0.09 2.64 0.2 Lot runoff drains to a rear lot vegetated swale A2 A2 0.39 0.66 7.9 0.26 2.47 0.6 Lot and private street runoff drains to a vegetated swale A3 A3 0.48 0.66 10.1 0.32 2.24 0.7 Lot and private street runoff drains to a vegetated swale A4 A4 0.41 0.55 9.1 0.23 2.35 0.5 Lot runoff drains to a rear lot vegetated swale A5 A5 0.40 0.40 11.0 0.16 2.17 0.3 On-stie detention pond B1 B1 0.28 0.67 7.2 0.19 2.56 0.5 Runoff drains to Pear Street (existing) OS1 OS1 0.44 0.80 5.6 0.35 2.77 1.0 Right-of-Way runoff drains to West Elizabeth Street C&G DIRECT RUNOFF TOTAL RUNOFF STREET PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) 2-Year 12/26/17 Page 1 of 1 12/26/2017 STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) Project Name: 2620 West Elizabeth Street Subdivision: Elizabeth Street Farms Project No.: HPB01.01 Location: CO, Fort Collins Calculated By: H. Feissner Design Storm: Checked By: H. Feissner Date: TRAVEL TIME STREET Design Point Basin ID Area (Ac) Runoff Coeff. | C 100 Tc | 100-Year (min) C*A (Ac) I (in/hr) Q (cfs) Tc (min) C*A (Ac) I (in/hr) Q (cfs) Slope (%) Street Flow (cfs) Design Flow (cfs) Slope (%) Pipe Size (inches) Length (ft) Velocity (fps) Tt (min) REMARKS A1 A1 0.16 0.75 5.0 0.12 9.98 1.2 Lot runoff drains to a rear lot vegetated swale A2 A2 0.39 0.83 6.0 0.32 9.48 3.0 Lot and private street runoff drains to a vegetated swale A3 A3 0.48 0.82 7.7 0.40 8.72 3.5 Lot and private street runoff drains to a vegetated swale A4 A4 0.41 0.69 7.6 0.28 8.76 2.5 Lot runoff drains to a rear lot vegetated swale A5 A5 0.40 0.49 9.9 0.20 7.92 1.6 On-stie detention pond B1 B1 0.28 0.84 5.0 0.24 9.98 2.4 Runoff drains to Pear Street (existing ) OS1 OS1 0.44 1.00 5.0 0.44 9.98 4.4 Right-of-Way runoff drains to West Elizabeth Street C&G 100-Year DIRECT RUNOFF TOTAL RUNOFF STREET 12/26/17 PIPE Page 1 of 1 12/26/2017 ` APPENDIX C HYDRAULIC CALCULATIONS ` SWALE CAPACITY CALCULATIONS Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.035 Channel Slope 0.005 ft/ft Normal Depth 1.00 ft Left Side Slope 4.00 ft/ft (H:V) Right Side Slope 3.00 ft/ft (H:V) Normal Depth (ft) Discharge (ft³/s) Velocity (ft/s) Flow Area (ft²) Wetted Perimeter (ft) Top Width (ft) 0.00 0.00 0.00 0.00 0.10 0.01 0.40 0.04 0.73 0.70 0.20 0.09 0.63 0.14 1.46 1.40 0.30 0.26 0.83 0.32 2.19 2.10 0.40 0.56 1.00 0.56 2.91 2.80 0.50 1.02 1.16 0.88 3.64 3.50 0.60 1.65 1.31 1.26 4.37 4.20 0.70 2.49 1.45 1.72 5.10 4.90 0.80 3.55 1.59 2.24 5.83 5.60 0.90 4.87 1.72 2.84 6.56 6.30 1.00 6.45 1.84 3.50 7.29 7.00 Vegetated Swale 11/1/2016 9:49:52 AM Bentley Systems, Inc. Haestad Methods Solution BentleCyenter FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 ` CULVERT SIZING Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 19 2017 DP A1 | (2) - 8 in. HDPE Culverts Invert Elev Dn (ft) = 8.90 Pipe Length (ft) = 56.31 Slope (%) = 0.30 Invert Elev Up (ft) = 9.07 Rise (in) = 8.0 Shape = Circular Span (in) = 8.0 No. Barrels = 2 n-Value = 0.013 Culvert Type = Circular Concrete Culvert Entrance = Groove end projecting (C) Coeff. K,M,c,Y,k = 0.0045, 2, 0.0317, 0.69, 0.2 Embankment Top Elevation (ft) = 10.00 Top Width (ft) = 35.00 Crest Width (ft) = 35.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 1.20 Tailwater Elev (ft) = Crown Highlighted Qtotal (cfs) = 1.20 Qpipe (cfs) = 1.20 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 1.72 Veloc Up (ft/s) = 3.08 HGL Dn (ft) = 9.57 HGL Up (ft) = 9.43 Hw Elev (ft) = 9.59 Hw/D (ft) = 0.79 Flow Regime = Inlet Control Hydraflow Express - DP A1 | (2) - 8 in. HDPE Culverts - 12/19/17 1 Q Veloc Depth HGL Total Pipe Over Dn Up Dn Up Dn Up (cfs) (cfs) (cfs) (ft/s) (ft/s) (in) (in) (ft) (ft) 0.40 0.40 0.00 0.57 2.19 8.00 2.47 9.57 9.28 0.80 0.80 0.00 1.15 1.26 8.00 6.85 9.57 9.64 1.20 1.20 0.00 1.72 3.08 8.00 4.37 9.57 9.43 Hydraflow Express - DP A1 | (2) - 8 in. HDPE Culverts - 12/19/17 2 HGL Hw Hw/D (ft) 9.35 0.42 9.67 0.90 9.59 0.79 017 Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Hydraflow Express - DP A2 | (2) - 8 in. HDPE Culverts - 12/19/17 1 Q Veloc Depth HGL Total Pipe Over Dn Up Dn Up Dn Up (cfs) (cfs) (cfs) (ft/s) (ft/s) (in) (in) (ft) (ft) 0.50 0.50 0.00 0.72 2.34 8.00 2.77 9.18 8.96 1.00 1.00 0.00 1.43 2.89 8.00 3.97 9.18 9.06 1.50 1.50 0.00 2.15 3.33 8.00 4.93 9.18 9.14 2.00 2.00 0.00 2.87 3.75 8.00 5.71 9.18 9.21 2.50 2.50 0.00 3.58 4.20 8.00 6.36 9.18 9.26 3.00 3.00 0.00 4.30 4.70 8.00 6.88 9.18 9.30 Hydraflow Express - DP A2 | (2) - 8 in. HDPE Culverts - 12/19/17 2 HGL Hw Hw/D (ft) 9.04 0.47 9.19 0.70 9.33 0.90 9.46 1.09 9.59 1.29 9.77 1.56 Culvert Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Tuesday, Dec 26 2017 DP A3 | (3) - 8in. HDPE Culverts Invert Elev Dn (ft) = 8.14 Pipe Length (ft) = 45.94 Slope (%) = 2.18 Invert Elev Up (ft) = 9.14 Rise (in) = 8.0 Shape = Circular Span (in) = 8.0 No. Barrels = 3 n-Value = 0.013 Culvert Type = Circular Concrete Culvert Entrance = Square edge w/headwall (C) Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 Embankment Top Elevation (ft) = 10.25 Top Width (ft) = 35.00 Crest Width (ft) = 35.00 Calculations Qmin (cfs) = 0.00 Qmax (cfs) = 3.50 Tailwater Elev (ft) = Crown Highlighted Qtotal (cfs) = 3.50 Qpipe (cfs) = 3.50 Qovertop (cfs) = 0.00 Veloc Dn (ft/s) = 3.34 Veloc Up (ft/s) = 4.06 HGL Dn (ft) = 8.81 HGL Up (ft) = 9.65 Hw Elev (ft) = 10.02 Hw/D (ft) = 1.33 Flow Regime = Inlet Control Hydraflow Express - DP A3 | (3) - 8in. HDPE Culverts - 12/26/17 1 Q Veloc Depth HGL Total Pipe Over Dn Up Dn Up Dn Up (cfs) (cfs) (cfs) (ft/s) (ft/s) (in) (in) (ft) (ft) 0.50 0.50 0.00 0.48 2.08 8.00 2.24 8.81 9.33 1.00 1.00 0.00 0.96 2.54 8.00 3.21 8.81 9.41 1.50 1.50 0.00 1.43 2.89 8.00 3.97 8.81 9.47 2.00 2.00 0.00 1.91 3.20 8.00 4.61 8.81 9.52 2.50 2.50 0.00 2.39 3.48 8.00 5.18 8.81 9.57 3.00 3.00 0.00 2.87 3.77 8.00 5.69 8.81 9.61 3.50 3.50 0.00 3.34 4.06 8.00 6.14 8.81 9.65 Hydraflow Express - DP A3 | (3) - 8in. HDPE Culverts - 12/26/17 2 HGL Hw Hw/D (ft) 9.39 0.37 9.51 0.55 9.61 0.71 9.71 0.86 9.81 1.00 9.91 1.15 10.02 1.33 017 Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Hydraflow Express - DP A4 | (3) - 8in. HDPE Culverts - 12/26/17 1 Q Veloc Depth HGL Total Pipe Over Dn Up Dn Up Dn Up (cfs) (cfs) (cfs) (ft/s) (ft/s) (in) (in) (ft) (ft) 0.50 0.50 0.00 0.48 2.08 8.00 2.24 9.06 9.39 1.00 1.00 0.00 0.96 2.54 8.00 3.21 9.06 9.47 1.50 1.50 0.00 1.43 2.89 8.00 3.97 9.06 9.53 2.00 2.00 0.00 1.91 3.20 8.00 4.61 9.06 9.58 2.50 2.50 0.00 2.39 3.48 8.00 5.18 9.06 9.63 Hydraflow Express - DP A4 | (3) - 8in. HDPE Culverts - 12/26/17 2 HGL Hw Hw/D (ft) 9.45 0.38 9.57 0.55 9.67 0.70 9.76 0.83 9.84 0.96 ` DETENTION POND SIZING Project Number: HPB01.01 Date: 12/19/2017 Project Location: Fort Collins, Colorado Calculations By: H. Feissner Pond Description: Basin A5 User Input Cell: Blue Text 100-year 9385 0.72 0.22 1.84 1.2 minutes seconds in/hr cubic feet cubic feet cubic feet acre-feet 5 300 9.95 3955 360 3595 0.08 10 600 7.72 6136 720 5416 0.12 15 900 6.52 7774 1080 6694 0.15 20 1200 5.60 8903 1440 7463 0.17 25 1500 4.98 9896 1800 8096 0.19 30 1800 4.52 10779 2160 8619 0.20 35 2100 4.08 11351 2520 8831 0.20 40 2400 3.74 11891 2880 9011 0.21 45 2700 3.46 12376 3240 9136 0.21 50 3000 3.23 12837 3600 9237 0.21 55 3300 3.03 13247 3960 9287 0.21 60 3600 2.86 13640 4320 9320 0.21 65 3900 2.71 14002 4680 9322 0.21 70 4200 2.59 14411 5040 9371 0.22 75 4500 2.48 14785 5400 9385 0.22 80 4800 2.38 15135 5760 9375 0.22 85 5100 2.29 15472 6120 9352 0.21 90 5400 2.21 15810 6480 9330 0.21 95 5700 2.13 16084 6840 9244 0.21 100 6000 2.06 16375 7200 9175 0.21 105 6300 2.00 16692 7560 9132 0.21 110 6600 1.94 16963 7920 9043 0.21 115 6900 1.88 17185 8280 8905 0.20 120 7200 1.84 17551 8640 8911 0.20 Storage Volume Modified FAA Method- Storage Colume Calculations Inputs | Tributary Area Output | Detention Volume Storm Duration Time Rainfall Intensity Inflow Volume Catchment 'C': Catchment Drainage Area, ac: Return Period for Detention Control: Required Storage, cubic feet: Required Storage, ac-ft: Release Rate, cfs: Average Outflow Storage Volume Project Description Solve For Discharge Input Data Headwater Elevation 5109.60 ft Centroid Elevation 5107.84 ft Tailwater Elevation 5107.60 ft Discharge Coefficient 0.64 Diameter 0.475 ft Results Discharge 1.21 ft³/s Headwater Height Above Centroid 1.76 ft Tailwater Height Above Centroid -0.24 ft Flow Area 0.18 ft² Velocity 6.82 ft/s 100-year Orifice Plate | DP A5 12/19/2017 11:15:09 AM Bentley Systems, Inc. Haestad Methods Solution BentleCyenter FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Project Description Solve For Discharge Input Data Headwater Elevation 5109.80 ft Crest Elevation 5109.60 ft Tailwater Elevation 5107.60 ft Crest Surface Type Paved Crest Breadth 0.50 ft Crest Length 40.00 ft Results Discharge 11.04 ft³/s Headwater Height Above Crest 0.20 ft Tailwater Height Above Crest -2.00 ft Weir Coefficient 3.09 US Submergence Factor 1.00 Adjusted Weir Coefficient 3.09 US Flow Area 8.00 ft² Velocity 1.38 ft/s Wetted Perimeter 40.40 ft Top Width 40.00 ft Emergency Spillway | DP A5 12/26/2017 10:11:41 AM Bentley Systems, Inc. Haestad Methods Solution BentleCyenter FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Project Number: HPB01.01 Project Location: Fort Collins, Colorado Date: 12/19/2017 Calculations By: H. Feissner Pond Description: Basin A5 User Input Cell: Blue Text Design Point: A1 Design Storm: N/A Required Volume: 0 ft 3 5107.60 ft Design Storm: N/A Required Volume: 0 ft 3 5107.60 ft Design Storm: 100-year Required Volume: 9385 ft 3 5109.60 ft Contour Elevation Contour Area Depth Incremental Volume Cummulative Volume Incremental Volume Cummulative Volume Cummulative Volume ft ft 2 ft ft 3 ft 3 ft 3 ft 3 ac-ft 5107.60 0 0 0 0 0 0 0.000 5107.70 16 0.10 1 1 1 1 0.000 5107.80 125 0.10 7 8 6 7 0.000 5107.90 466 0.10 30 37 28 34 0.001 5108.00 1093 0.10 78 115 76 110 0.003 5108.10 1889 0.10 149 264 147 258 0.006 5108.20 2634 0.10 226 491 225 483 0.011 5108.30 3487 0.10 306 797 305 788 0.018 5108.40 4297 0.10 389 1186 388 1176 0.027 5108.50 5021 0.10 466 1652 465 1642 0.038 5108.60 5463 0.10 524 2176 524 2166 0.050 5108.70 5871 0.10 567 2743 567 2732 0.063 5108.80 6233 0.10 605 3348 605 3337 0.077 5108.90 6582 0.10 641 3989 641 3978 0.091 5109.00 6872 0.10 673 4661 673 4651 0.107 5109.10 7241 0.10 706 5367 706 5356 0.123 5109.20 7572 0.10 741 6108 741 6097 0.140 5109.30 7916 0.10 774 6882 774 6871 0.158 ` APPENDIX D DRAINAGE MAPS + VARIANCE APPLICATION PEAR STREET WEST ELIZABETHSTREET DRIVEWAY PEAR STREET WEST ELIZABETHSTREET 12''IRR 12''IRR 12''IRR 12''IRR W ATER WELL EX2 VALLEY HI SUBDIVISION BLOCK 4 WEST PLUM STREET- A PLANNED UNIT RHODES DEVELOPMENT SUBDIVISION WEST PLUM STREET- A PLANNED UNIT DEVELOPMENT EX4 EX5 EX3 EX2 EX1 EX1 EX3 EX4 EX5 EXISTING IRRIGATION LATERAL EXISTING IRRIGATION STRUCTURE EXISTING IRRIGATION STRUCTURE EXISTING HOUSE # 3760 E. 15th Street, Suite 202 Loveland, CO 80538 970.800.3300 O www.gallowayUS.com 2016. Galloway & Company, Inc. All Rights Reserved Date: Drawn By: Project No: Checked By: THESE PLANS ARE AN INSTRUMENT OF SERVICE AND ARE THE PROPERTY OF GALLOWAY, AND MAY NOT BE DUPLICATED, DISCLOSED, OR REPRODUCED WITHOUT THE WRITTEN CONSENT OF GALLOWAY. COPYRIGHTS AND INFRINGEMENTS WILL BE ENFORCED AND PROSECUTED. COPYRIGHT H:\High Plains Builders\CO, Fort Collins - HPB000001.01 - Elizabeth & Pear\CADD\Exhibit\HPB1.01_Exist-DR.dwg LAYOUT NAME: EXIST DATE: Jul 12, 2017 - 10:18am CAD OPERATOR: herman_feissner LIST OF XREFS: [x-HPB1.01_EMap] [x-HPB1.01_ESite] [x-HPB1.01_ETopo] [x-HPB1.01_EUtil] [x-HPB1.01_Legend_DR-Exist] NOT FOR CONSTRUCTION 07.12.2017 This unofficial copy was downloaded on Sep-12-2017 from the City of Fort Collins Public Records Website: http:/citydocs.fcgov.com For additional information or an official copy, please contact Engineering Office 281 North College Fort Collins, CO 80521 USA Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.035 Channel Slope 0.010 ft/ft Left Side Slope 8.33 % Right Side Slope 8.33 % Discharge 5.09 ft³/s Results Normal Depth 0.50 ft Flow Area 3.02 ft² Wetted Perimeter 12.08 ft Hydraulic Radius 0.25 ft Top Width 12.04 ft Critical Depth 0.41 ft Critical Slope 0.03049 ft/ft Velocity 1.69 ft/s Velocity Head 0.04 ft Specific Energy 0.55 ft Froude Number 0.59 Flow Type Subcritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.50 ft Critical Depth 0.41 ft Channel Slope 0.010 ft/ft Critical Slope 0.03049 ft/ft Section C-C | W. Plum Street - P.U.D. | EXISTING 12/18/2017 6:27:11 PM Bentley Systems, Inc. Haestad Methods Solution BentleCyenter FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 Project Description Friction Method Manning Formula Solve For Normal Depth Input Data Roughness Coefficient 0.035 Channel Slope 0.010 ft/ft Left Side Slope 8.33 % Right Side Slope 8.33 % Discharge 7.49 ft³/s Results Normal Depth 0.58 ft Flow Area 4.04 ft² Wetted Perimeter 13.97 ft Hydraulic Radius 0.29 ft Top Width 13.92 ft Critical Depth 0.48 ft Critical Slope 0.02896 ft/ft Velocity 1.86 ft/s Velocity Head 0.05 ft Specific Energy 0.63 ft Froude Number 0.61 Flow Type Subcritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.58 ft Critical Depth 0.48 ft Channel Slope 0.010 ft/ft Critical Slope 0.02896 ft/ft Section C-C | W. Plum Street - P.U.D. | PROPOSED 12/18/2017 6:27:42 PM Bentley Systems, Inc. Haestad Methods Solution BentleCyenter FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 1 HIGH PLAINS BUILDERS, LLC P.O. Box 2796 Gillette, WY 82717 307.257.2352 ( IN FEET ) 1 inch = ft. 30 0 30 30 60 90 Tributary Area C2 C 100 tc | 2-Year tc | 100-Year Q 2 Q100 Sub-basin (acres) (min) (min) (cfs) (cfs) EX1 0.05 0.20 0.25 5.0 5.0 0.03 0.11 EX2 0.10 0.20 0.25 8.7 8.2 0.05 0.21 EX3 0.18 0.20 0.25 5.0 5.0 0.10 0.45 EX4 0.76 0.23 0.29 27.1 25.3 0.24 1.08 EX5 1.26 0.22 0.28 30.4 28.5 0.35 1.60 DRAINAGE SUMMARY TABLE | EXISTING CONDITION 4550 DESIGN POINT MAJOR BASIN BOUNDARY SUB-BASIN BOUNDARY OVERLAND FLOW DIRECTION (I.E., LANDSCAPING) EX1 DRAINAGE SYMBOLS: LEGEND: DIRECT FLOW DIRECTION (I.E., PAVEMENT, CURB AND GUTTER, SWALE) 4552 EXISTING MAJOR CONTOUR EXISTING MINOR CONTOUR EXISTING STORM SEWER EASEMENT LINE 5109.40 8259 0.10 809 7691 809 7680 0.176 5109.50 8604 0.10 843 8534 843 8523 0.196 5109.60 9102 0.10 885 9419 885 9408 0.216 5109.70 9757 0.10 943 10362 943 10351 0.238 Detention Pond Stage-Storage Calculations Required Volume Water Surface Elevation Average End Area Method: Conic Volume Method: 100-year 5107.6 5108.1 5108.6 5109.1 5109.6 5110.1 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Contour Elevation, ft Cummulative Volume, ft3 Stage - Storage | Site Survey Area Data: Version 10, Sep 22, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Apr 22, 2011—Apr 28, 2011 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—Larimer County Area, Colorado (2620 West Elizabeth Street) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/25/2016 Page 2 of 4