Loading...
HomeMy WebLinkAboutLARIMER COUNTY CORRECTIONS ALTERNATIVE SENTENCING - SPA210002 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT PRELIMINARY DRAINAGE ANALYSIS ASD/COMCOR EXPANSION PROJECT 2307 MIDPOINT DRIVE FORT COLLINS COLORADO Prepared For Larimer County Facilities Department 200 West Oak Fort Collins Colorado Prepared By AVI PC 2290 East Prospect, Suite 5 Fort Collins Colorado May 19th, 2021 TABLE OF CONTENTS INTRODUCTION ............................................................................................................................................. 1  EXISTING CONDITIONS .................................................................................................................................. 1  DESIGN CRITERIA ........................................................................................................................................... 2  EXISTING BASIN COMPARISION .................................................................................................................... 2  DETAILED SITE DRAINAGE SYSTEM ............................................................................................................... 4  CONCLUSIONS ............................................................................................................................................... 5  ENGINEER’S CERTIFICATION ......................................................................................................................... 5    ASD/COMCOR EXPANSION 0427 AVI PROFESSIONAL CORPORATION 2290 E. PROSPECT ROAD STE 5 FORT COLLINS, CO 80525 Page 1 of 5 ASD/COMCOR EXPANSION PRELIMINARY DRAINAGE ANALYSIS INTRODUCTION The Alternative Sentencing Department/Community Corrections (ASD/COMCOR) Expansion is located within the existing Larimer County Detention Center Complex. It is situated in the Northwest Quarter of Section 20, Township 7 North, Range 9/ West of the Sixth Principal Meridian. The proposed expansion is adjacent the existing ASD building and is located on portions of lots one and two of the Larimer County Midpoint Campus, 2nd Filing. The Larimer county Detention Center Complex encompasses approximately 36 acres in total. The ASD/COMCOR Expansion includes a building addition of 28,135 sf, additional parking areas, sidewalks, a crusher fine trail loop, and utility infrastructure including water, sanitary and storm sewer systems. A grading plan with site improvements is included in Appendix F. This report describes the drainage plan for new stormwater features being installed with the expansion and the utilization of the existing storm sewer infrastructure in place. It will also evaluate the original design of the existing regional detention pond to verify the capacity can accommodate the proposed expansion. The regional detention pond design and associated calculations were part of the existing drainage study by Nolte Vertical Five titled ‘Larimer County Detention Center Master Drainage Plan’ dated September 2011. This report will be referred to as the “Master Drainage Report.” An amendment to this report was completed May 21,2020 by Martin/Martin Inc for the ‘Larimer County Jail Expansion.’ This report will be referred to as the “Amended Drainage Report.” EXISTING CONDITIONS The existing Larimer County Detention Complex includes four existing buildings, (an expansion to the existing Jail building is currently under construction), paved access drives and parking areas and an open area which is covered in native grasses. Existing ASD/COMCOR EXPANSION 0427 AVI PROFESSIONAL CORPORATION 2290 E. PROSPECT ROAD STE 5 FORT COLLINS, CO 80525 Page 2 of 5 stormwater drainage generally flows to the south and southeast to a regional detention and stormwater quality pond. Flows are conveyed via surface and storm sewer pipes. The National Resources Conservation Service (NRCS) Web Soil Survey classifies the existing soils within the proposed expansion area as Caruso clay loam, 0 to 1 percent slope, with a soil classification of D and a small area being Loveland clay loam, 0 to 1 percent slopes, with a soil classification of C. A map including the soil classifications can be found in Appendix B. DESIGN CRITERIA The design criteria for the site follows the City of Fort Collins Stormwater Criteria Manual (FCSCM), dated 2018. The ‘Larimer County Detention Center Master Drainage Plan’ (Master Drainage Report) and the ‘Larimer County Jail Expansion Final Drainage Report’ (Amended Drainage Report) were also used for reference. The rational method was used to determine peak flow rates. Runoff coefficient values were determined using Tables 3.2-2 and 3.2-3 in Chapter 5 of the FCSCM. Rainfall intensities were determined using Table 3.3-1 in Chapter 5 of the FCSCM. The four-step process was considered when implementing the storm design and erosion control plans. To reduce runoff peaks, volumes and pollutant loads vegetative areas were used to slow down and route storm water runoff through within the proposed improvements. Best Management Practices include vegetative buffers and swales to treat stormwater runoff prior to entering the detention pond. There are no streams located within the site and so stream stabilization was not considered. Site specific BMPS to be installed during and after construction can be seen on the stormwater plan. EXISTING BASIN COMPARISION Historically this site drains southeasterly into the Cache La Poudre River. The site is within the Cache La Poudre Basin and within zone X, areas determined to be outside the 0.2% annual chance floodplain according to the FEMA Flood Insurance Rate Map for Larimer County, Map Number 08069C0983H, dated May 2, 2019. The Master Drainage Report divided the Detention Center Complex into nine sub- basins: A1-A6, B1, B2 and C1 and two off-site sub-basins C2 and D1. The proposed ASD/COMCOR EXPANSION 0427 AVI PROFESSIONAL CORPORATION 2290 E. PROSPECT ROAD STE 5 FORT COLLINS, CO 80525 Page 3 of 5 ASD expansion is located within the existing sub-basin C1 and this report will only look at this sub-basin. The Amended Drainage Report subdivided the original C1 basin into two sub-basins, CR and C1P. Existing peak flow rates and runoff coefficients from the Amended drainage report for basins CR and C1P are shown below: Table 1: Existing Runoff Summary RUNOFF SUMMARY BASIN AREA (ACRES) IMPERVIOUS % C2 C10 C100 Q2 Q10 Q100 C1P 21.11 35.3% 0.46 0.46 0.58 18.16 30.98 79.14 CR 1.51 88.8% 0.94 0.94 1.00 4.05 6.91 15.02 SITE COMPOSITE 22.61 38.9% 0.49 0.49 0.61 22.21 37.89 94.16 The Rational Method was used to analyze runoff for both the Master Drainage Report and the Amended Drainage report, it will be used herein to accurately compare existing conditions to the proposed improvements with the expansion. The drainage basins CR and C1P analyzed in the Amended Drainage Report will be analyzed with the proposed ASD Expansion. The overall proposed drainage patterns will be similar to the existing conditions. Basin CR: Sub-basin CR is unchanged with the proposed expansion. Basin C1P: Sub-basin C1P will remain largely unchanged from the existing basin C1P, it includes the ASD building expansion and paved access drives and parking areas have increased. The proposed expansion will result in an increase of impervious area of 1.60 acres, of which 0.64 acres are building and 0.96 acres are paved surfaces. A map showing the additional impervious and pervious areas can be seen in Appendix F. Runoff will be conveyed via overland flow and storm sewer systems to the existing regional detention pond. Calculated peak flow rates for basins CR and C1P are shown in the table below. Table 2: Proposed Runoff Summary RUNOFF SUMMARY BASIN AREA (ACRES) IMPERVIOUS % C2 C10 C100 Q2 Q100 C1P 21.11 41.3% 0.51 0.51 0.63 25.49 109.57 CR 1.51 88.8% 0.94 0.94 1.00 4.05 15.02 SITE COMPOSITE 22.61 44.4% 0.54 0.54 0.68 29.54 124.59 ASD/COMCOR EXPANSION 0427 AVI PROFESSIONAL CORPORATION 2290 E. PROSPECT ROAD STE 5 FORT COLLINS, CO 80525 Page 4 of 5 See the table below for the comparison of the existing conditions and the proposed conditions. Table 3: Runoff Comparison Summary RUNOFF SUMMARY BASIN AREA (ACRES) IMPERVIOUS % C2 C10 C100 Q2 Q100 Existing 22.61 38.9% 0.49 0.49 0.61 22.21 94.16 Proposed 22.61 44.4% 0.54 0.54 0.68 29.54 124.59 The Amended Drainage Report states that for the new tributary area to the pond (Basins C1P and CR), the runoff coefficient shall not exceed 0.78 in future development. The Master Drainage Report designed the existing detention pond assuming a future build-out condition. The proposed improvements for the ASD expansion do not exceed the future build-out condition, therefore the existing detention pond has adequate capacity and does not need to be modified. DETAILED SITE DRAINAGE SYSTEM The proposed development has been analyzed as 8 onsite basins, basins 1 through 8. A map showing these basins can be seen in Appendix F. These basins encompass an area of 2.51 acres for the proposed expansion. The Rational Method will be used to determine peak flows for the site. Based on Fort Collins Storm Management Criteria the design storm frequencies for the project are the 2 year (minor) and 100 year (major). The following table summarizes the basin’s area, runoff coefficient values and flow rates. Table 4: ASD Expansion Basin Summary BASIN SUMMARY BASIN AREA (ACRES) C2 C100 Q2 Q100 1 1.33 0.70 0.88 2.96 13.01 2 0.26 0.95 1.00 0.84 3.08 3 0.11 0.95 1.00 0.35 1.30 4 0.13 0.95 1.00 0.42 1.54 5 0.01 0.95 1.00 0.03 0.12 6 0.28 0.95 1.00 0.90 3.32 7 0.21 0.95 1.00 0.68 2.49 8 0.17 0.95 1.00 0.51 1.89 COMPOSITE 2.51 0.81 0.93 6.97 26.75 ASD/COMCOR EXPANSION 0427 AVI PROFESSIONAL CORPORATION 2290 E. PROSPECT ROAD STE 5 FORT COLLINS, CO 80525 Page 5 of 5 The proposed development will have an increase of impervious area of 1.60 acres. Runoff will be collected in a storm sewer system that discharges southeast of the site towards the detention pond. A portion of the runoff will be treated prior to entering the detention facilities through a bio-swale in the southern parking area. Runoff that does not enter the storm sewer system will sheet flow across the parking lot to southwest corner where it will enter a swale flowing southeasterly towards the detention pond. CONCLUSIONS Stormwater runoff for the site will be conveyed via overland flow and storm sewer systems to the existing detention pond to the southeast of the proposed improvements. The existing detention pond was sized assuming a future build-out condition with a greater runoff coefficient than this development produced, and so the existing pond will have capacity to handle runoff generated by these improvements. For the proposed improvements the peak flow rates were calculated using the rational method. The proposed storm sewer system was designed for the minor storm flows with consideration for major storm flows. The storm sewer system has capacity and/or overland flow capabilities to accommodate major storm events. A portion of the runoff for the improvements will be treated for water quality prior to entering the detention pond. ENGINEER’S CERTIFICATION I hereby attest that this report for the preliminary drainage design for the ASD/COMCOR Expansion was prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed by others. ________________________________ __________________ Signature Date APPENDIX A LARIMER COUNTY JAIL EXPANSION FINAL DRAINAGE REPORT, PREPARED BY MARTIN/MARTIN INC, DATED MAY 21, 2020 LARIMER COUNTY JAIL EXPANSION FINAL DRAINAGE REPORT 2405 MIDPOINT DRIVE, FORT COLLINS, CO Martin/Martin, Inc. Project No.: 19.0222 May 21, 2020 Prepared For: DLR GROUP 1401 LAWRENCE STREET, SUITE 1000 DENVER, COLORADO 80202 720.904.0440 Prepared By: MARTIN/MARTIN, INC. 12499 WEST COLFAX AVENUE LAKEWOOD, COLORADO 80215 303.431.6100 Principal-in-Charge: Mark Thornbrough, P.E., C.F.M. Project Manager: Joe Rausch, P.E. Project Engineers: Kayla Fochtman, EIT II and Moises Bonilla, EIT I TABLE OF CONTENTS I. GENERAL LOCATION AND DESCRIPTION ......................................................................................................1 A. Location ...................................................................................................................................................1 B. Project Description ..................................................................................................................................1 C. Existing Site Description ..........................................................................................................................2 II. DRAINAGE DESIGN CRITERIA .......................................................................................................................3 A. Development Criteria Reference ............................................................................................................3 B. Hydrologic Criteria ...................................................................................................................................3 C. UDFCD Four-Step Process .......................................................................................................................3 III. OVERALL DRAINAGE BASINS FOR HISTORIC COMPARISON .........................................................................3 A. Major Basin Description ..........................................................................................................................3 B. Sub-Basin Descriptions ............................................................................................................................3 C. Drainage Facility Design ..........................................................................................................................5 IV. DEVELOPED DETAILED SITE DRAINAGE SYSTEM ..........................................................................................7 A. General Concept ......................................................................................................................................7 B. Runoff ......................................................................................................................................................7 C. Low Impact Development .......................................................................................................................9 V. CONCLUSIONS ..............................................................................................................................................9 VI. CITY OF FORT COLLINS COMPLIANCE STATEMENT ................................................................................... 10 REFERENCES ...................................................................................................................................................... 11 APPENDICES A. Excerpt of Larimer County Detention Center Master Drainage Plan, Prepared by Nolte Vertical Five, Dated September 2011 B. Web Soil Survey C. Cache La Poudre Basin Map D. FEMA FIRM E. Overall Basin Rational Method Calculations F. Existing Detention Pond Evaluation and Maximum Runoff Coefficient Calculations G. Hydraulic Computations for Site Storm System a. Rational Method Calculations b. Inlet Capacity Computations H. StormCAD Model for the Site Storm System I. Low Impact Development Calculations and Rain Garden Design J. Drainage Plans K. City of Fort Collins Standard Operating Procedures P a g e 1 | 10 I. GENERAL LOCATION AND DESCRIPTION A. Location The Larimer County Detention site is located in the Northwest Quarter of Section 20, Township 7 North, Range 68 West of the 6th Principal Meridian within the City of Fort Collins, Larimer County, Colorado. The site is bordered on the north and east by Midpoint Drive, on the south and west by the OmniTRAX railroad and an irrigation ditch, and on the west by Centerpoint Plaza. Figure 1: Vicinity Map B. Project Description The Larimer County Detention Center site has a total size of approximately 36 acres. The proposed development includes an expansion of the Larimer County Jail building as well as the addition of several new parking lots and driveways. New utilities including storm sewer will also be constructed as part of this development. LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 2 | 10 The purpose of this drainage report is to describe new stormwater features being implemented and the utilization of the existing storm infrastructure on site. This drainage report will aslo demonstrate that the proposed development will not require any additional stormwater detention facilities as the expansion of the site has already been accounted for in a previous study: Larimer County Detention Center Master Drainage Plan prepared by Nolte Vertical Five, dated September 2011. This report will be referred to as the “Master Drainage Report.” C. Existing Site Description Existing Land-Use and Ground Cover: According to the City of Fort Collins zoning maps, the site currently resides within the Employment District, the Industrial District, and the Transition District. Existing buildings on the site include the Community Corrections building (referred to as the CC building), the Alternative Sentencing building (referred to as the AS building), the Jail building, and the Sheriff’s Administration building (referred to as the Administration building). The site also contains paved driveways, paved parking, graveled parking, and a large field consisting of native grasses. Ponds and Irrigation Ditches: The Larimer County Detention Center site currently has two stormwater detention ponds. There is a small irrigation ditch/railroad ditch along the western property boundary. Historically, there was another irrigation ditch that ran east-west through the middle of the site. This ditch was removed during an earlier phase of development. Existing Topography: In general, the existing site slopes northeasterly and southeasterly at an average slope of approximately 0.5%. The existing drainage patterns are as follows: · The area surrounding the CC building is sloped northeast towards an existing detention pond and discharges at a 2-year historic rate to Midpoint Drive. · Existing topography in the area between the Jail building and CC building directs runoff northeast via overland flow towards Midpoint Drive. · In the area northeast and east of the Jail building, runoff is conveyed easterly via overland flow towards Midpoint Drive. · Runoff in the existing parking lot between the Jail building and the Administration building is conveyed east towards Midpoint Drive. · The Administration building and the parking lot south of the building direct runoff easterly to an existing detention pond. The pond discharges to Midpoint Drive. · Existing topography for the AS building, the parking lots south of the AS building, a portion of the Jail building, the parking lot west of the Administration building, and the field at the southern half of the site direct runoff southeasterly via overland flow and storm sewer to an existing detention. Existing Soil Conditions: According to the National Resources Conservation Service (NRCS) Web Soil Survey, the existing soils on site consist mostly of Caruso clay loam, 0 to 1 percent slopes (Hydrologic Soil Group LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 3 | 10 (HSG) Class D), with small portion of the site being Table Mountain loam, 0 to 1 percent slopes (HSG Class B) and Loveland clay loam, 0 to 1 percent slopes (HSG Class C). II. DRAINAGE DESIGN CRITERIA A. Development Criteria Reference The design criteria for this study site are directly from the City of Fort Collins Stormwater Criteria Manual (referred to as the F.C. Manual), dated December 2018. The Larimer County Detention Center Master Drainage Plan (known as the Master Drainage Report) prepared by Nolte Vertical Five, dated September 2011 was also used as a reference. B. Hydrologic Criteria The peak flow rates were calculated using the Rational Method as described in the F.C. Manual. Runoff coefficient values were determined using Tables 3.2-2 and 3.2-3 in Chapter 5 of the F.C. Manual. Rainfall intensities were determined using Table 3.3-1 in Chapter 5 of the F.C. Manual. C. UDFCD Four-Step Process The four-step process was considered when implementing this storm design and a plan for erosion control. To (1) employ runoff reduction practices, landscaped areas were used whenever possible to allow overland flow and reduce runoff peaks. (2) Best Management Practices were described (more thoroughly in the Storm Water Management Plan) for during and following construction to improve water quality. Similarly, an rain garden was designed for site to treat a significant amount of stormwater before it enters the detention basin. Due to lack of streams on site, (3) stabilizing streams was not considered. And finally, (4) site specific BMPs will be utilized during and following construction to improve stormwater quality. Primary source of pollution is runoff from vehicle parking areas and drive aisles. This will be treated by the proposed Rain Garden BMP. III. OVERALL DRAINAGE BASINS FOR HISTORIC COMPARISON A. Major Basin Description The site historically drains southeast into the Cache La Poudre River. According to the City of Fort Collins drainage basin maps at the time of this report, the Larimer County Detention Center site is located within the Cache La Poudre Basin. A map of the basin can be found in the Appendix. Per the FEMA Flood Insurance Rate Map (FIRM) for Larimer County, Map Number 08069C0983H, dated May 2, 2019, the site is located within Zone X (area outside of the limits of the 500-year flood). Refer to the Appendix for the FIRM. B. Sub-Basin Descriptions LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 4 | 10 The site currently consists of nine sub-basins: A1-A6, B1, B2, and C1. These basins are based on the proposed basins delineated in the Master Drainage Report. The drainage plan showing these basins can be found in the Appendix. For the purposes of this drainage report, only existing basins C1 and A1 were analyzed as they are the only basins that will be impacted by the proposed development. Basin C1: Sub-basin C1 drains to the southeast and into an existing detention pond at the south end of the site. From the detention pond, runoff is ultimately conveyed to Skunk Pond via storm sewer. The basin is composed of the AS building, a portion of the Jail building, paved driveways, paved parking, gravel parking, and a vacant field at the southern half of the site. Basin C1 experiences offsite flows from Basin C2. See the drainage plan from the Master Drainage Report in the Appendix for the delineation of Basin C2. According to the Master Drainage Report, for the more frequent storm events, runoff from C2 is not detained in the existing detention pond and is instead conveyed through the pond’s outfall storm pipe. During the 100-year event, runoff from Basin C2 is conveyed via the pond’s emergency spillway into an existing swale south of the site. As such, offsite flows from C2 were not considered in the design of the detention pond for C1 and will not be further considered in this drainage analysis. Basin A1: Sub-basin A1 drains to the northeast towards Midpoint Drive and runoff is ultimately conveyed easterly via the Midpoint Drive cross-pan. The basin is composed of most of the Jail building, paved driveways, paved parking, and landscaping. This basin does not experience any offsite flows. Calculated peak flow rates for Basins C1 and A1 are shown in the table on the next page and on the Existing Drainage Plan (C250). Refer to the Appendix for the complete Rational method calculations performed in 2011 for determining these values. Table 1: Existing Runoff Summary RUNOFF SUMMARY BASIN AREA (ACRES) % Imp. C2 C10 C100 Q2 (CFS) Q10 (CFS) Q100 (CFS) C1 21.53 26.3% 0.39 0.39 0.49 15.70 26.79 68.43 A1 6.98 52.6% 0.61 0.61 0.76 9.41 16.09 41.09 SITE COMPOSITE 28.51 32.8% 0.44 0.44 0.55 25.11 42.88 109.52 It should be noted that these flow rates are less than those presented in the Master Drainage Report. As an example, for the 100-year event, the Master Drainage Report calculates a flow rate of 115.35 cfs for Basin C1. This outcome supports the Master Drainage Report’s claim that the designed the stormwater facilities (i.e. the existing detention pond in Basin C1) are based on a future expansion. LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 5 | 10 The size of Basin A1 was reduced during the 2011 Master Drainage Report design, reducing the size of the basin from approximately 13.90 acres to 6.98 acres. Treated by other facilities in the Advanced Energy site to the east, the Master Drainage Report anticipated flows of 37.79 cfs during the 100-year event with a 100-year runoff coefficient of 0.70. However, the 1998 Drainage Report entitled Final Drainage Report for the Larimer County Detention Center Expansion anticipated 60.4 cfs from this area to the Advanced Energy site and established this flow as the maximum allowable stormwater event for this basin. C. Drainage Facility Design 1. General Concept Since the Rational Method was used to analyze runoff for the 2011 Drainage Study, it will be used herein to accurately compare existing conditions to proposed. The proposed drainage pattern is divided into three new basins: CR, C1P, and A1P. Overall, the proposed drainage patterns will be similar to the existing conditions. See the Overall Proposed Drainage Plan in the Appendix for reference. The newly defined basins will cover the extent of the proposed development which is the same area covered by basins C1 and A1. Basin CR: Sub-basin CR includes the roof area for the Jail building expansion. Runoff will be conveyed via roof drains and storm sewer and will outfall to the existing detention pond at the south end of the site. Basin C1P: Sub-basin C1P will remain largely unchanged from existing Basin C1 except that the boundary has been modified to exclude the expansion of the Jail Building and the paved parking/driveway areas have increased. Runoff from Basin C1P is conveyed southeasterly via overland flow and storm sewer to the existing detention pond at the south end of the site. Basin A1P: Sub-basin A1P will remain largely unchanged from existing Basin A1 except that the boundary has been modified to exclude the expansion of the Jail building. Runoff for this basin will drain to the northeast towards Midpoint Drive and ultimately conveyed easterly via the Midpoint Drive cross-pan. Calculated peak flow rates for proposed Basins CR, C1P, and A1P are shown in the summary table below and on the Proposed Drainage Plan (C251). Refer to the Appendix for the complete Rational method calculations for determining these values. LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 6 | 10 Table 2: Proposed Runoff Summary RUNOFF SUMMARY BASIN AREA (ACRES) % Imp. C2 C10 C100 Q2 (CFS) Q10 (CFS) Q100 (CFS) C1P 21.11 35.3% 0.46 0.46 0.58 18.16 30.98 79.14 A1P 5.89 53.4% 0.62 0.62 0.78 8.07 13.80 35.24 CR 1.51 88.8% 0.94 0.94 1.00 4.05 6.91 15.02 SITE COMPOSITE 28.51 41.9% 0.52 0.52 0.64 30.27 51.69 129.41 2. Future Buildout Additional housing towers are anticipated in the future, leading to increased imperviousness. These housing towers would be located exclusively in Basin C1, and are anticipated to be two towers with approximately 14,000SF footprints, each (total of 28,000SF). Anticipated peak flow rates for the future buildout basins CR-FB, C1-FB, and A1-FB are shown in the table below for comparison purposes. Table 3: Estimated Future Build-out Runoff Summary RUNOFF SUMMARY BASIN AREA (ACRES) % Imp. C2 C10 C100 Q2 (CFS) Q10 (CFS) Q100 (CFS) C1-FB 21.11 37.5% 0.48 0.48 0.60 18.95 32.32 82.58 A1-FB 5.89 53.4% 0.62 0.62 0.78 8.07 13.80 35.24 CR-FB 1.51 88.8% 0.94 0.94 1.00 4.05 6.91 15.02 SITE COMPOSITE 28.51 43.5% 0.53 0.53 0.66 31.06 53.04 132.85 See the table below for comparison of all three conditions: the existing condition, the proposed condition, and the anticipated future build-out condition. Due to the changes in basin sizes, this table compares total site conditions for existing Basins A1 and C1, of which A1 is not detained in the existing detention pond. Table 4: Runoff Summary Comparison RUNOFF SUMMARY COMPARISON BASIN AREA (ACRES) % Imp. C2 C10 C100 Q2 (CFS) Q10 (CFS) Q100 (CFS) Existing 28.51 32.8% 0.44 0.44 0.55 25.11 42.88 109.52 Proposed 28.51 41.9% 0.52 0.52 0.64 30.27 51.69 129.41 Future Build 28.51 43.5% 0.53 0.53 0.66 31.06 53.04 132.85 3. Existing Detention Pond Evaluation The Master Drainage Report designed the existing detention pond at the south end of the site assuming a future build-out condition, with a runoff coefficient (C100) of 0.82. The proposed improvements increase the tributary area and the imperviousness of the basins tributary to the detention pond. However, the runoff coefficient of the proposed tributary area was calculated LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 7 | 10 to be 0.61 (when including Basins C1P AND CR, excluding Basin A1). Even when different tributary areas were compared, the proposed condition was calculated to be only a portion of the imperviousness anticipated by the Master Drainage Report (see the appendix for additional information). Therefore, the existing detention pond has adequate capacity for the proposed improvements and does not need to be modified. For the new tributary area to the detention pond (basins C1P and CR), the runoff coefficient shall not exceed 0.78 in future development. If this value is exceeded, the detention pond shall be modified to account for the increased runoff. 4. Conclusion The Master Drainage Report designed the existing detention pond assuming a future build-out condition. The proposed improvements do not exceed this future build-out condition. Therefore, the existing detention pond has adequate capacity and does not need to be modified. IV. DEVELOPED DETAILED SITE DRAINAGE SYSTEM A. General Concept The site of proposed development has been analyzed as nineteen onsite basins, Basins 1 through 19. These basins equal a total area of 13.59 acres for the site being developed with a total imperviousness of 69.4%. Hydrologic method of analysis for peak flows for the site is the Rational Method. Design storm frequencies for the project are minor (2-year) and major (100-year) based on Fort Collins Storm Management criteria. B. Runoff Please see appendix for calculations of developed peak flow rates. The site has been analyzed into nineteen basins, Basins 1 through 19. Routed flows for Basins 2, 3, and 19 were estimated using satellite mapping and rainfall data in the area. The storm system and inlet capacities were considered for both minor and major storm events. Basin 1 consists of landscape and parking areas to the east of the proposed building; this basin flows to the east, to Design Point 1, where it is conveyed offsite and easterly via the Midpoint Drive cross- pan. This basin is referred to as part of Basin A1P in historical drainage reports and remains largely unchanged but is included in analysis as verification that runoff does not increase in this basin. The existing curb inlets in the drive aisle north of the development are Basins 2 and 3; these are included to represent flows entering the existing storm system. Basin 2 includes mostly area to the north with some landscaping at the north edge of the site, draining to Design Point 2, a curb inlet, to LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 8 | 10 be piped into the existing storm system. Basin 3 includes the loading area to the north of the new building addition as well as mechanical equipment area, in addition to the tributary areas to the north of the existing curb inlet, Design Point 3. Basin 19 is a tributary basin for an existing curb inlet that must be removed and replaced by a Type 16 Valley Inlet due to the location of the new proposed drive. This new proposed inlet is defined as Design Point 19 and is anticipated to have a 100-year flow of 4.32 cfs. Due to the inlet capacity, it is possible that ponding may occur around the inlet for the major storm event at a maximum depth of 6.5 inches (at a maximum of 20 feet into the drive north of the inlet and a maximum of 6 feet into the proposed drive aisle). The loading dock and mechanical equipment area north of the proposed building is Basin 4; stormwater is primarily collected in trench drains immediately north of the building (Design Point 4) to be conveyed into the proposed storm system. Basin 5 includes primarily pavement, both existing and proposed, to the west of the proposed building. Stormwater will be conveyed into the existing storm system via two existing curb inlets, Design Point 5. Basin 6 includes some roof of the existing building and the alcove between the existing and proposed jail portions; this basin conveys runoff to several area inlets which convey storm water into the storm system by a new storm line. There are seven roof drains anticipated for the proposed building expansion; these are accounted for by Basins 7-13 and their respective design points. Basin 14 is primarily pavement, including some existing parking and proposed drives just south of the proposed building expansion. This area slopes to the southeast to an existing curb inlet, Design Point 14. The anticipated major storm event peak runoff is 5.28 cfs. Due to the expected capacity of this inlet, some ponding may occur in the event of a major 100-year storm event (at a maximum of 8 in). In such a case, stormwater may overtop the curb and enter Basin 17, in which the curb inlet in Basin 17 has sufficient capacity for additional flow, or additional stormwater may run south to Basin 18, to eventually be conveyed to the southern rain garden. The proposed recycled asphalt parking and existing canine area, as well as some undeveloped area to the north are Basin 15. Runoff for this basin will be conveyed south to the southern curb (Design Point 15) which will be flush, allowing stormwater to sheet flow into the existing detention pond. Basin 16 includes the rest of the undeveloped area west of the proposed building expansion. This stormwater will flow to a proposed valley inlet, Design Point 16, to be conveyed through the proposed storm system. Some ponding may occur at this inlet in the case of a major storm event; this ponding would be, at maximum, 5.3 in. LARIMER COUNTY JAIL EXPANSION May 21, 2020 P a g e 9 | 10 Most parking to the immediate southwest of the building expansion is Basin 17. While most of the Sheriff Building basin is accommodated with an existing detention pond to the southeast of the building and this basin remains unchanged from historic conditions (named Basin B1), there is a small portion of the existing southern parking lot that drains to the west that is also part of Basin 17. This basin’s stormwater will be conveyed to the west of the basin to an existing curb inlet (Design Point 17) to enter into the existing storm system. The additional southern parking lots are Basin 18. These parking areas will drain to the south, to allow runoff to sheet flow over a flush curb on the southern end, Design Point 18, to be conveyed to a rain garden water quality feature which upon treatment, will release flows to the existing detention pond. C. Low Impact Development The proposed site is anticipated to have an imperviousness of 41.9% with an addition of approximately 113,000 SF, or 2.59 acres, of impervious area being added over the site. To treat a portion of the runoff without disturbing existing storm infrastructure, the southern portion of the site, approximately 2.54 acres and consisting mostly of proposed parking, will allow stormwater to sheet flow overland to the southern portion of the site, to a rain garden immediately upgradient of the existing detention pond. The rain garden was sized to provide water quality filtration for the increased imperviousness on site, resulting in a rain garden with a volume of 3,076 ft3 (see appendix for further information). The calculations of new impervious area and the rain garden sizing was based on the current proposed condition but do not consider the future build-out condition (of additional housing towers). The rain garden design was modeled after Fort Collins’s detail D-53 for Bioretention and is designed to be approximately 9.0 ft in width and 535 feet in length with an anticipated ponding depth of 6 in. An underdrain will collect filtered stormwater and convey it to the existing detention pond on the south corner of the site. Flows in excess of the WQCV will be conveyed to the detention pond via four inlets located within the rain garden. V. CONCLUSIONS Stormwater runoff from the proposed development will be conveyed to the existing detention pond system adjacent of the site, to the south. The existing detention pond was originally sized for a development with an expected net imperviousness that is higher than the developed conditions and will be sufficient to accommodate runoff generated by the proposed development. The peak flow rates have been calculated using the Rational Method for the site storm system. Existing inlets have been verified and proposed inlets designed for minor storm flows, with consideration for flows from major storms. All inlets have adequate capacity, minor ponding, or overland flow capabilities to accommodate major storm events. A portion of the site will be treated for water quality with a rain garden, which will treat overland stormwater before it enters the detention pond. LARIMER COUNTY JAIL EXPANSION May 7, 2020 P a g e 10 | 10 VI. CITY OF FORT COLLINS COMPLIANCE STATEMENT I hereby attest that this report for the final drainage design for the Larimer County Jail Expansion was prepared by me or under my direct supervision, in accordance with the provisions of the Fort Collins Stormwater Criteria Manual. I understand that the City of Fort Collins does not and will not assume liability for drainage facilities designed by others. _________________________________________________ __________________ Signature Date REFERENCES 1. 2018. Google Earth Image of Larimer County Detention Center. 2. (September 2011). Larimer County Detention Center Master Drainage Plan. Nolte Vertical Five. 3. (Adopted: March 27, 1997). City of Fort Collins Land Use Code. 4. Web Soil Survey. United States Department of Agriculture, Natural Resources Conservation Service. 5. City of Fort Collins Drainage Basin Maps. 6. FEMA Flood Map Service Center. U.S. Department of Homeland Security. 7. (December 2018). City of Fort Collins Stormwater Criteria Manual. APPENDIX A Excerpt of Larimer County Detention Center Master Drainage Plan, Prepared by Nolte Vertical Five, Dated September 2011 APPENDIX B Web Soil Survey Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/29/2019 Page 1 of 4448990044901004490300449050044907004490900448990044901004490300449050044907004490900496400496600496800497000497200497400497600497800498000 496400 496600 496800 497000 497200 497400 497600 497800 498000 40° 34' 10'' N 105° 2' 40'' W40° 34' 10'' N105° 1' 21'' W40° 33' 31'' N 105° 2' 40'' W40° 33' 31'' N 105° 1' 21'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 400 800 1600 2400 Feet 0 100 200 400 600 Meters Map Scale: 1:8,560 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. 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: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 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 Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/29/2019 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 6 Aquepts, ponded A/D 5.5 1.5% 22 Caruso clay loam, 0 to 1 percent slope D 115.7 31.4% 42 Gravel pits A 18.2 4.9% 53 Kim loam, 1 to 3 percent slopes B 1.1 0.3% 54 Kim loam, 3 to 5 percent slopes B 5.0 1.3% 60 Larim gravelly sandy loam, 5 to 40 percent slopes B 1.9 0.5% 62 Larimer-Stoneham complex, 3 to 10 percent slopes B 19.4 5.3% 64 Loveland clay loam, 0 to 1 percent slopes C 79.7 21.6% 73 Nunn clay loam, 0 to 1 percent slopes C 40.0 10.8% 74 Nunn clay loam, 1 to 3 percent slopes C 1.3 0.4% 81 Paoli fine sandy loam, 0 to 1 percent slopes A 4.4 1.2% 92 Riverwash A 41.7 11.3% 101 Stoneham loam, 1 to 3 percent slopes B 2.6 0.7% 102 Stoneham loam, 3 to 5 percent slopes C 2.6 0.7% 105 Table Mountain loam, 0 to 1 percent slopes B 19.8 5.4% 136 Water 9.9 2.7% Totals for Area of Interest 368.5 100.0% Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/29/2019 Page 3 of 4 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 Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Larimer County Area, Colorado Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/29/2019 Page 4 of 4 APPENDIX C Cache La Poudre Basin Map PROJECT SITE APPENDIX D FEMA FIRM Project Site APPENDIX E Overall Basin Rational Method Calculations PROJECT INFORMATION PROJECT NAME: PROJECT NO: DESIGN BY: REVIEWED BY: JURISDICTION: REPORT TYPE: DATE: C2 C5 C10 C100 % IMPERV 0.20 0.20 0.20 - 2% 0.95 0.95 0.95 - 90% 0.50 0.50 0.50 - 40% 0.95 0.95 0.95 - 100% 28.51 0.52 0.52 0.52 0.64 41.9% AREA (ACRES) C2 C5 C10 C100 0.88 0.95 0.95 0.95 - 90% 6.16 0.95 0.95 0.95 - 100% 0.59 0.50 0.50 0.50 - 40% 13.48 0.20 0.20 0.20 - 2% 21.11 0.46 0.46 0.46 0.58 35.3% AREA (ACRES) C2 C5 C10 C100 1.79 0.95 0.95 0.95 - 90% 1.18 0.95 0.95 0.95 - 100% 0.78 0.50 0.50 0.50 - 40% 2.14 0.20 0.20 0.20 - 2% 5.89 0.62 0.62 0.62 0.78 53.4% AREA (ACRES) C2 C5 C10 C100 1.49 0.95 0.95 0.95 - 90% 0.02 0.20 0.20 0.20 - 2% 1.51 0.94 0.94 0.94 1.00 88.8% 28.51 0.52 0.52 0.52 0.64 41.9% PERCENT IMPERVIOUSNESS CR ROOF LANDSCAPE SUB-BASIN COMPOSITE TOTAL SITE COMPOSITE SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS SUB-BASIN COMPOSITE C1P LANDSCAPE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS A1P ROOF PAVED GRAVEL LANDSCAPE PAVED GRAVEL COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS ROOF LANDSCAPE PAVED TOTAL SITE COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS LARIMER COUNTY SPAR 08/30/19 JURISDICTIONAL STANDARD LARIMER COUNTY JAIL EXPANSION 19.0222 MB MS GRAVEL ROOF 5/27/2020 9:01 PM COMPOSITE_C-VALUES G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm CALCULATED BY:JOB NO:CHECKED BY:PROJECT:DATE:Is Project Urban? YesAREA LENGTH SLOPEtiLENGTH SLOPE VEL.ttCOMP.TOT. LENGTH SLOPE IMPtc tcac ft ft/ft min ft ft/ft fps min tc ft ft/ft % First DP min(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)(16) (17)C1P - 0.46 21.11 - - #VALUE! - - #VALUE! #VALUE! #VALUE! #VALUE! #VALUE! 35.3% #VALUE! #VALUE!A1P - 0.62 5.89 - - #VALUE! - - #VALUE! #VALUE! #VALUE! #VALUE!#VALUE! 53.4% #VALUE! #VALUE!CR - 0.94 1.51 150 0.0100 3.50.00 0.0 3.5 150.0 0.01 88.8% 5.0*Velocity (V) = CvSw0.5TABLE 6-2*Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5in which: Cv = Conveyance Coefficient (See Table Above)Sw = Watercourse Slope (ft/ft)BASINDESIGN POINTC5CvDATASUB-BASINTIME (ti)(tt)Paved Areas and Shallow Paved Swales20Heavy Meadow2.5Tillage / FieldNearly Bare Ground10Grassed Waterway155Short Pasture and Lawns7Type of Land SurfaceConveyance Coefficient, Cv19.0222LARIMER COUNTY JAIL EXPANSIONSTANDARD FORM SF-2(RATIONAL METHOD PROCEDURE)REMARKStc CHECK (URBANIZED BASINS)MBMS08/30/19INITIAL/OVERLANDTIME OF CONCENTRATION SUMMARYTRAVEL TIMETOC5/27/2020 9:01 PMG:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm CALCULATED BY:MBJOB NO:19.0222CHECKED BY:MSPROJECT:LARIMER COUNTY JAIL EXPANSIONDATE:08/30/19DESIGN STORM:2-YEARONE-HR PRECIP:0.82(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)C1P - 21.11 0.46 15.0 9.71 1.87 18.16A1P - 5.89 0.62 10.0 3.65 2.21 8.07CR - 1.51 0.94 5.0 1.42 2.85 4.05I.One-Hr Precipitation Values from Fort Collins Stormwater Criteria ManualReturn Period: 2-YEAR 5-YEAR 10-YEAR 100-YEARDepth In Inches: 0.82 1.16 1.40 2.86*Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9*Rainfall Intensity:In Which: I = Rainfall Intensity (Inches Per Hour)P1 = 1-Hour Point Rainfall Depth (Inches)tc = Time Of Concentration (Minutes)REMARKSAREA (AC)RUNOFF COEFFtc (MIN)BASIN DESIGN POINTDIRECT RUNOFFTOTAL RUNOFFtc (MIN)S(CxA) (AC)I (IN/HR)Q (CFS)STANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)CxA (AC)I (IN/HR)Q (CFS)2-YEAR5/27/2020 9:02 PMG:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm CALCULATED BY:MBJOB NO:19.0222CHECKED BY:MSPROJECT:LARIMER COUNTY JAIL EXPANSIONDATE:08/30/19DESIGN STORM:5-YEARONE-HR PRECIP:1.16(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)C1P - 21.11 0.46 #VALUE! 9.71 0.00 0.00A1P - 5.89 0.62 #VALUE! 3.65 0.00 0.00CR - 1.51 0.94 5.0 1.42 3.93 5.58I. One-Hr Precipitation Values from Fort Collins Stormwater Criteria ManualReturn Period: 2-YEAR 5-YEAR 10-YEAR 100-YEARDepth In Inches: 0.82 1.16 1.40 2.86*Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9*Rainfall Intensity:In Which: I = Rainfall Intensity (Inches Per Hour)P1 = 1-Hour Point Rainfall Depth (Inches)tc = Time Of Concentration (Minutes)REMARKSAREA (AC)RUNOFF COEFFtc (MIN)STANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)CxA (AC)I (IN/HR)Q (CFS)BASIN DESIGN POINTDIRECT RUNOFFTOTAL RUNOFFtc (MIN)S(CxA) (AC)I (IN/HR)Q (CFS)5-YEAR5/27/2020 9:03 PMG:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm CALCULATED BY:MBJOB NO:19.0222CHECKED BY:MSPROJECT:LARIMER COUNTY JAIL EXPANSIONDATE:08/30/19DESIGN STORM:10-YEARONE-HR PRECIP:1.4(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)C1P - 21.11 0.46 15.0 9.71 3.19 30.98A1P - 5.89 0.62 10.0 3.65 3.78 13.80CR - 1.51 0.94 5.0 1.42 4.87 6.91I. One-Hr Precipitation Values from Fort Collins Stormwater Criteria ManualReturn Period: 2-YEAR 5-YEAR 10-YEAR 100-YEARDepth In Inches: 0.82 1.16 1.40 2.86*Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9*Rainfall Intensity:In Which: I = Rainfall Intensity (Inches Per Hour)P1 = 1-Hour Point Rainfall Depth (Inches)tc = Time Of Concentration (Minutes)REMARKSAREA (AC)RUNOFF COEFFtc (MIN)BASIN DESIGN POINTDIRECT RUNOFFTOTAL RUNOFFtc (MIN)S(CxA) (AC)I (IN/HR)Q (CFS)STANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)CxA (AC)I (IN/HR)Q (CFS)10-YEAR5/27/2020 9:03 PMG:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm CALCULATED BY:MBJOB NO:19.0222CHECKED BY:MSPROJECT:LARIMER COUNTY JAIL EXPANSIONDATE:08/30/19DESIGN STORM:100-YEARONE-HR PRECIP:2.86(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)C1P - 21.11 0.58 15.0 12.14 6.52 79.14A1P - 5.89 0.78 10.0 4.56 7.72 35.24CR - 1.51 1.00 5.0 1.51 9.95 15.02I. One-Hr Precipitation Values from Fort Collins Stormwater Criteria ManualReturn Period: 2-YEAR 5-YEAR 10-YEAR 100-YEARDepth In Inches: 0.82 1.16 1.40 2.86*Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9*Rainfall Intensity:In Which: I = Rainfall Intensity (Inches Per Hour)P1 = 1-Hour Point Rainfall Depth (Inches)tc = Time Of Concentration (Minutes)REMARKSAREA (AC)RUNOFF COEFFtc (MIN)STANDARD FORM SF-3STORM DRAINAGE SYSTEM DESIGN(RATIONAL METHOD PROCEDURE)CxA (AC)I (IN/HR)Q (CFS)BASIN DESIGN POINTDIRECT RUNOFFTOTAL RUNOFFtc (MIN)S(CxA) (AC)I (IN/HR)Q (CFS)100-YEAR5/27/2020 9:04 PMG:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm PROJECT: JOB NO:01/19/00 DATE:08/30/19 DESIGN AREA % Q2 Q10 Q100 POINT (ACRES) IMP.(CFS) (CFS) (CFS) C1P - 21.11 35.3% 0.46 0.46 0.58 18.16 30.98 79.14 A1P - 5.89 53.4% 0.62 0.62 0.78 8.07 13.80 35.24 CR - 1.51 88.8% 0.94 0.94 1.00 4.05 6.91 15.02 28.51 41.9% 0.52 0.52 0.64 30.27 51.69 129.41 LARIMER COUNTY JAIL EXPANSION SITE COMPOSITE BASIN RUNOFF SUMMARY C2 C100C10 RUNOFF_SUMMARY 5/27/2020 9:04 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational (Non-UDFCD).xlsm APPENDIX F Existing Detention Pond Evaluation and Maximum Runoff Coefficient Calculations 881118 11 APPENDIX G Hydraulic Computations for Site Storm System Rational Method Calculations Inlet Capacity Computations PROJECT INFORMATION PROJECT NAME: PROJECT NO: DESIGN BY: REVIEWED BY: JURISDICTION: REPORT TYPE: DATE: C2 C5 C10 C100 % IMPERV 0.95 0.95 0.95 1.19 95% 0.95 0.95 0.95 1.19 95% 0.80 0.80 0.80 1.00 80% 0.50 0.50 0.50 0.63 50% 13.59 0.69 0.69 0.69 0.83 69.4% AREA (ACRES)C2 C5 C10 C100 0.57 0.95 0.95 0.95 1.19 95% 0.91 0.25 0.25 0.25 0.31 25% 1.48 0.52 0.52 0.52 0.65 52.0% AREA (ACRES)C2 C5 C10 C100 0.37 0.95 0.95 0.95 1.19 95% 0.41 0.95 0.95 0.95 1.19 95% 0.31 0.25 0.25 0.25 0.31 25% 1.09 0.75 0.75 0.75 0.94 75.1% AREA (ACRES)C2 C5 C10 C100 0.13 0.95 0.95 0.95 1.19 95% 0.17 0.95 0.95 0.95 1.19 95% 0.24 0.20 0.20 0.20 0.25 20% 0.54 0.62 0.62 0.62 0.77 61.7% AREA (ACRES)C2 C5 C10 C100 0.14 0.20 0.20 0.20 0.25 20% 0.22 0.95 0.95 0.95 1.19 95% 0.21 0.95 0.95 0.95 1.19 95% 0.57 0.77 0.77 0.77 0.96 76.6% AREA (ACRES)C2 C5 C10 C100 0.47 0.95 0.95 0.95 1.19 95% 0.17 0.20 0.20 0.20 0.25 20% 0.64 0.75 0.75 0.75 0.94 75.1% AREA (ACRES)C2 C5 C10 C100 0.32 0.95 0.95 0.95 1.19 95% 0.04 0.95 0.95 0.95 1.19 95% 0.17 0.25 0.25 0.25 0.31 25% 0.53 0.73 0.73 0.73 0.91 72.5% AREA (ACRES)C2 C5 C10 C100 Larimer County Jail Expansion 19.0222 KNF JER RECYCLED ASPHALT 1 ASPHALT/CONCRETE GRAVEL TOTAL SITE COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS Fort Collins Drainage Report 02/04/20 JURISDICTIONAL STANDARD COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS ASPHALT/CONCRETE ROOF LANDSCAPE, CLAYEY, 2-7% SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 2 ROOF ASPHALT/CONCRETE LANDSCAPE, CLAYEY, 2-7% 3 ROOF ASPHALT/CONCRETE LANDSCAPE, CLAYEY, <2% SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 4 LANDSCAPE, CLAYEY, <2% ASPHALT/CONCRETE ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 5 ASPHALT/CONCRETE LANDSCAPE, CLAYEY, <2% SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 6 ROOF ASPHALT/CONCRETE LANDSCAPE, CLAYEY, 2-7% SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 5/7/2020 6:55 PM COMPOSITE_C-VALUES G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm 0.33 0.95 0.95 0.95 1.19 95% 0.33 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.08 0.95 0.95 0.95 1.19 95% 0.08 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.15 0.95 0.95 0.95 1.19 95% 0.15 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.15 0.95 0.95 0.95 1.19 95% 0.15 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.24 0.95 0.95 0.95 1.19 95% 0.24 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.24 0.95 0.95 0.95 1.19 95% 0.24 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.06 0.95 0.95 0.95 1.19 95% 0.06 0.95 0.95 0.95 1.00 95.0% AREA (ACRES)C2 C5 C10 C100 0.42 0.95 0.95 0.95 1.19 95% 0.05 0.25 0.25 0.25 0.31 25% 0.47 0.88 0.88 0.88 1.00 87.6% AREA (ACRES)C2 C5 C10 C100 0.38 0.80 0.80 0.80 1.00 80% 0.19 0.95 0.95 0.95 1.19 95% 0.01 0.95 0.95 0.95 1.19 95% 1.01 0.25 0.25 0.25 0.31 25% 1.59 0.47 0.47 0.47 0.59 46.9% 15 RECYCLED ASPHALT ASPHALT/CONCRETE ROOF LANDSCAPE, CLAYEY, 2-7% SUB-BASIN COMPOSITE 7 ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 8 ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 9 ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 10 ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS PERCENT IMPERVIOUSNESS 12 ROOF SUB-BASIN COMPOSITE 11 ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 13 ROOF SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 14 ASPHALT/CONCRETE LANDSCAPE, CLAYEY, 2-7% PERCENT IMPERVIOUSNESS 5/7/2020 6:55 PM COMPOSITE_C-VALUES G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm AREA (ACRES)C2 C5 C10 C100 0.59 0.25 0.25 0.25 0.31 25% 0.59 0.25 0.25 0.25 0.31 25.0% AREA (ACRES)C2 C5 C10 C100 0.12 0.25 0.25 0.25 0.31 25% 1.03 0.95 0.95 0.95 1.19 95% 0.04 0.20 0.20 0.20 0.25 20% 1.19 0.85 0.85 0.85 1.00 85.4% AREA (ACRES)C2 C5 C10 C100 0.40 0.20 0.20 0.20 0.25 20% 2.14 0.95 0.95 0.95 1.19 95% 2.54 0.83 0.83 0.83 1.00 83.2% AREA (ACRES)C2 C5 C10 C100 0.42 0.95 0.95 0.95 1.19 95% 0.05 0.50 0.50 0.50 0.63 50% 0.64 0.25 0.25 0.25 0.31 25% 1.11 0.53 0.53 0.53 0.66 52.6% 13.59 0.69 0.69 0.69 0.83 69.4%TOTAL SITE COMPOSITE PERCENT IMPERVIOUSNESS PERCENT IMPERVIOUSNESS 19 ASPHALT/CONCRETE GRAVEL LANDSCAPE, CLAYEY, 2-7% SUB-BASIN COMPOSITE 18 LANDSCAPE, CLAYEY, <2% ASPHALT/CONCRETE SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS 17 LANDSCAPE, CLAYEY, 2-7% ASPHALT/CONCRETE LANDSCAPE, CLAYEY, <2% SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS 16 LANDSCAPE, CLAYEY, 2-7% SUB-BASIN COMPOSITE SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS PERCENT IMPERVIOUSNESS SUB-BASIN SURFACE CHARACTERISTICS COMPOSITE RUNOFF COEFFICIENTS 5/7/2020 6:55 PM COMPOSITE_C-VALUES G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm CALCULATED BY:JOB NO: CHECKED BY:PROJECT: DATE: Is Project Urban?Yes AREA LENGTH SLOPE ti LENGTH SLOPE VEL.tt COMP.TOT. LENGTH SLOPE IMP tc tc ac ft ft/ft min ft ft/ft fps min tc ft ft/ft %First DP min (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) 1 1 0.52 1.48 423 0.0163 18.3 0.00 0.0 18.3 423.0 0.02 52.0%18.3 2 2 0.75 1.09 268 0.0037 14.4 0.00 0.0 14.4 268.0 0.00 75.1%14.4 3 3 0.62 0.54 220 0.0055 15.7 25 0.0100 20 2.00 0.2 15.9 245.0 0.01 61.7%15.8 15.8 4 4 0.77 0.57 84 0.0164 4.6 57 0.0107 20 2.07 0.5 5.1 141.0 0.01 76.6%13.4 5.1 5 5 0.75 0.64 83 0.0220 4.4 23 0.0252 20 3.17 0.1 4.6 106.0 0.02 75.1%13.4 5.0 6 6 0.73 0.53 124 0.0084 7.9 70 0.0154 7 0.87 1.3 9.2 194.0 0.01 72.5%14.2 9.2 7 7 0.95 0.33 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 8 8 0.95 0.08 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 9 9 0.95 0.15 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 10 10 0.95 0.15 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 11 11 0.95 0.24 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 12 12 0.95 0.24 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 13 13 0.95 0.06 0.0 0.00 0.0 0.0 0.0 #DIV/0!95.0%5.0 14 14 0.88 0.47 168 0.0142 4.6 0.00 0.0 4.6 168.0 0.01 87.6%5.0 15 15 0.47 1.59 342 0.0130 19.3 0.00 0.0 19.3 342.0 0.01 46.9%19.3 16 16 0.25 0.59 45 0.0127 9.5 91 0.0050 7 0.49 3.1 12.6 136.0 0.01 25.0%23.5 12.6 17 17 0.85 1.19 275 0.0116 7.1 0.00 0.0 7.1 275.0 0.01 85.4%7.1 18 18 0.83 2.54 305 0.0150 7.4 0.00 0.0 7.4 305.0 0.02 83.2%7.4 19 19 0.53 1.11 212 0.0055 18.3 0.00 0.0 18.3 212.0 0.01 52.6%18.3 *Velocity (V) = CvSw0.5 TABLE 6-2 *Table 6-2, UDFCD (V.1), Chapter 6, Page 6-5 in which:Cv = Conveyance Coefficient (See Table Above) Sw = Watercourse Slope (ft/ft) KNF JER 02/04/20 INITIAL/OVERLAND TIME OF CONCENTRATION SUMMARY TRAVEL TIME 19.0222 Larimer County Jail Expansion STANDARD FORM SF-2 (RATIONAL METHOD PROCEDURE) REMARKS tc CHECK (URBANIZED BASINS) Type of Land Surface Conveyance Coefficient, Cv Nearly Bare Ground 10 Grassed Waterway 15 5 Short Pasture and Lawns 7 Paved Areas and Shallow Paved Swales 20 Heavy Meadow 2.5 Tillage / Field BASIN DESIGN POINT C5 Cv DATA SUB-BASIN TIME (ti)(tt) TOC 5/7/2020 6:56 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm CALCULATED BY:KNF JOB NO:19.0222 CHECKED BY:JER PROJECT:Larimer County Jail Expansion DATE:02/04/20 DESIGN STORM:2-YEAR ONE-HR PRECIP:0.82 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) 1 1 1.48 0.52 18.3 0.77 1.69 1.30 2 2 1.09 0.75 14.4 0.82 1.90 1.55 3 3 0.54 0.62 15.8 0.33 1.82 0.61 4 4 0.57 0.77 5.1 0.44 2.77 1.21 5 5 0.64 0.75 5.0 0.48 2.78 1.34 6 6 0.53 0.73 9.2 0.39 2.29 0.89 7 7 0.33 0.95 5.0 0.31 2.78 0.87 8 8 0.08 0.95 5.0 0.08 2.78 0.21 9 9 0.15 0.95 5.0 0.14 2.78 0.40 10 10 0.15 0.95 5.0 0.14 2.78 0.40 11 11 0.24 0.95 5.0 0.23 2.78 0.63 12 12 0.24 0.95 5.0 0.23 2.78 0.63 13 13 0.06 0.95 5.0 0.06 2.78 0.16 14 14 0.47 0.88 5.0 0.41 2.78 1.15 15 15 1.59 0.47 19.3 0.75 1.64 1.23 16 16 0.59 0.25 12.6 0.15 2.02 0.30 17 17 1.19 0.85 7.1 1.01 2.51 2.53 18 18 2.54 0.83 7.4 2.11 2.47 5.21 19 19 1.11 0.53 18.3 0.59 1.69 0.99 I.One-Hr Precipitation Values from Fort Collins Stormwater Criteria Manual Return Period:2-YEAR 5-YEAR 10-YEAR 100-YEAR Depth In Inches:0.82 1.16 1.40 2.86 *Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9 *Rainfall Intensity:In Which:I = Rainfall Intensity (Inches Per Hour) P1 = 1-Hour Point Rainfall Depth (Inches) tc = Time Of Concentration (Minutes) STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) CxA (AC) I (IN/HR) Q (CFS) REMARKSAREA (AC) RUNOFF COEFF tc (MIN) BASIN DESIGN POINT DIRECT RUNOFF TOTAL RUNOFF tc (MIN) S(CxA) (AC) I (IN/HR) Q (CFS) 2-YEAR 5/7/2020 6:57 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm CALCULATED BY:KNF JOB NO:19.0222 CHECKED BY:JER PROJECT:Larimer County Jail Expansion DATE:02/04/20 DESIGN STORM:5-YEAR ONE-HR PRECIP:1.16 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) 1 1 1.48 0.52 18.3 0.77 2.39 1.84 2 2 1.09 0.75 14.4 0.82 2.69 2.20 3 3 0.54 0.62 15.8 0.33 2.57 0.86 4 4 0.57 0.77 5.1 0.44 3.91 1.72 5 5 0.64 0.75 5.0 0.48 3.93 1.89 6 6 0.53 0.73 9.2 0.39 3.24 1.25 7 7 0.33 0.95 5.0 0.31 3.93 1.23 8 8 0.08 0.95 5.0 0.08 3.93 0.30 9 9 0.15 0.95 5.0 0.14 3.93 0.56 10 10 0.15 0.95 5.0 0.14 3.93 0.56 11 11 0.24 0.95 5.0 0.23 3.93 0.90 12 12 0.24 0.95 5.0 0.23 3.93 0.90 13 13 0.06 0.95 5.0 0.06 3.93 0.22 14 14 0.47 0.88 5.0 0.41 3.93 1.63 15 15 1.59 0.47 19.3 0.75 2.33 1.74 16 16 0.59 0.25 12.6 0.15 2.85 0.42 17 17 1.19 0.85 7.1 1.01 3.55 3.59 18 18 2.54 0.83 7.4 2.11 3.49 7.37 19 19 1.11 0.53 18.3 0.59 2.39 1.41 I.One-Hr Precipitation Values from Fort Collins Stormwater Criteria Manual Return Period:2-YEAR 5-YEAR 10-YEAR 100-YEAR Depth In Inches:0.82 1.16 1.40 2.86 *Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9 *Rainfall Intensity:In Which:I = Rainfall Intensity (Inches Per Hour) P1 = 1-Hour Point Rainfall Depth (Inches) tc = Time Of Concentration (Minutes) BASIN DESIGN POINT DIRECT RUNOFF TOTAL RUNOFF tc (MIN) S(CxA) (AC) I (IN/HR) Q (CFS) REMARKSAREA (AC) RUNOFF COEFF tc (MIN) STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) CxA (AC) I (IN/HR) Q (CFS) 5-YEAR 5/7/2020 6:57 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm CALCULATED BY:KNF JOB NO:19.0222 CHECKED BY:JER PROJECT:Larimer County Jail Expansion DATE:02/04/20 DESIGN STORM:10-YEAR ONE-HR PRECIP:1.4 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) 1 1 1.48 0.52 18.3 0.77 2.88 2.22 2 2 1.09 0.75 14.4 0.82 3.24 2.65 3 3 0.54 0.62 15.8 0.33 3.11 1.04 4 4 0.57 0.77 5.1 0.44 4.72 2.07 5 5 0.64 0.75 5.0 0.48 4.75 2.28 6 6 0.53 0.73 9.2 0.39 3.91 1.51 7 7 0.33 0.95 5.0 0.31 4.75 1.49 8 8 0.08 0.95 5.0 0.08 4.75 0.36 9 9 0.15 0.95 5.0 0.14 4.75 0.68 10 10 0.15 0.95 5.0 0.14 4.75 0.68 11 11 0.24 0.95 5.0 0.23 4.75 1.08 12 12 0.24 0.95 5.0 0.23 4.75 1.08 13 13 0.06 0.95 5.0 0.06 4.75 0.27 14 14 0.47 0.88 5.0 0.41 4.75 1.96 15 15 1.59 0.47 19.3 0.75 2.81 2.10 16 16 0.59 0.25 12.6 0.15 3.44 0.51 17 17 1.19 0.85 7.1 1.01 4.28 4.33 18 18 2.54 0.83 7.4 2.11 4.22 8.89 19 19 1.11 0.53 18.3 0.59 2.89 1.70 I.One-Hr Precipitation Values from Fort Collins Stormwater Criteria Manual Return Period:2-YEAR 5-YEAR 10-YEAR 100-YEAR Depth In Inches:0.82 1.16 1.40 2.86 *Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9 *Rainfall Intensity:In Which:I = Rainfall Intensity (Inches Per Hour) P1 = 1-Hour Point Rainfall Depth (Inches) tc = Time Of Concentration (Minutes) STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) CxA (AC) I (IN/HR) Q (CFS) REMARKSAREA (AC) RUNOFF COEFF tc (MIN) BASIN DESIGN POINT DIRECT RUNOFF TOTAL RUNOFF tc (MIN) S(CxA) (AC) I (IN/HR) Q (CFS) 10-YEAR 5/7/2020 6:58 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm CALCULATED BY:KNF JOB NO:19.0222 CHECKED BY:JER PROJECT:Larimer County Jail Expansion DATE:02/04/20 DESIGN STORM:100-YEAR ONE-HR PRECIP:2.86 (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13) 1 1 1.48 0.65 18.3 0.96 5.88 5.66 2 2 1.09 0.94 14.4 1.02 6.63 6.79 3 3 0.54 0.77 15.8 0.42 6.34 2.64 4 4 0.57 0.96 5.1 0.55 9.65 5.28 5 5 0.64 0.94 5.0 0.60 9.70 5.84 6 6 0.53 0.91 9.2 0.48 7.98 3.85 7 7 0.33 1.00 5.0 0.33 9.70 3.20 8 8 0.08 1.00 5.0 0.08 9.70 0.78 9 9 0.15 1.00 5.0 0.15 9.70 1.46 10 10 0.15 1.00 5.0 0.15 9.70 1.46 11 11 0.24 1.00 5.0 0.24 9.70 2.33 12 12 0.24 1.00 5.0 0.24 9.70 2.33 13 13 0.06 1.00 5.0 0.06 9.70 0.58 14 14 0.47 1.00 5.0 0.47 9.70 4.56 15 15 1.59 0.59 19.3 0.94 5.73 5.38 16 16 0.59 0.31 12.6 0.18 7.03 1.29 17 17 1.19 1.00 7.1 1.19 8.74 10.40 18 18 2.54 1.00 7.4 2.54 8.61 21.88 19 19 1.11 0.66 18.3 0.73 5.90 4.32 I.One-Hr Precipitation Values from Fort Collins Stormwater Criteria Manual Return Period:2-YEAR 5-YEAR 10-YEAR 100-YEAR Depth In Inches:0.82 1.16 1.40 2.86 *Equation 5-1, UDFCD (V.1), Chapter 5, Page 5-9 *Rainfall Intensity:In Which:I = Rainfall Intensity (Inches Per Hour) P1 = 1-Hour Point Rainfall Depth (Inches) tc = Time Of Concentration (Minutes) BASIN DESIGN POINT DIRECT RUNOFF TOTAL RUNOFF tc (MIN) S(CxA) (AC) I (IN/HR) Q (CFS) REMARKSAREA (AC) RUNOFF COEFF tc (MIN) STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN (RATIONAL METHOD PROCEDURE) CxA (AC) I (IN/HR) Q (CFS) 100-YEAR 5/7/2020 6:58 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non-UDFCD).xlsm PROJECT: JOB NO:01/19/00 DATE:02/04/20 DESIGN AREA %Q2 Q100 POINT (ACRES)IMP.(CFS)(CFS) 1 1 1.48 52.0%0.52 0.65 1.30 5.66 2 2 1.09 75.1%0.75 0.94 1.55 6.79 3 3 0.54 61.7%0.62 0.77 0.61 2.64 4 4 0.57 76.6%0.77 0.96 1.21 5.28 5 5 0.64 75.1%0.75 0.94 1.34 5.84 6 6 0.53 72.5%0.73 0.91 0.89 3.85 7 7 0.33 95.0%0.95 1.00 0.87 3.20 8 8 0.08 95.0%0.95 1.00 0.21 0.78 9 9 0.15 95.0%0.95 1.00 0.40 1.46 10 10 0.15 95.0%0.95 1.00 0.40 1.46 11 11 0.24 95.0%0.95 1.00 0.63 2.33 12 12 0.24 95.0%0.95 1.00 0.63 2.33 13 13 0.06 95.0%0.95 1.00 0.16 0.58 14 14 0.47 87.6%0.88 1.00 1.15 4.56 15 15 1.59 46.9%0.47 0.59 1.23 5.38 16 16 0.59 25.0%0.25 0.31 0.30 1.29 17 17 1.19 85.4%0.85 1.00 2.53 10.40 18 18 2.54 83.2%0.83 1.00 5.21 21.88 19 19 1.11 52.6%0.53 0.66 0.99 4.32 13.59 69.4%0.69 0.83 21.61 90.01 Larimer County Jail Expansion SITE COMPOSITE BASIN RUNOFF SUMMARY C2 C100 RUNOFF_SUMMARY 5/7/2020 6:58 PM G:\Thornbrough\19.0222-Larimer County Jail Expansion\ENG\DRAINAGE\Proposed Rational for Site Storm Infrastructure (Non- UDFCD).xlsm Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK = Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =30.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX =0.018 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =30.0 30.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 2 UD-Inlet.xlsm, Inlet 2 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =N/A N/A feet Width of a Unit Grate Wo =N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =N/A N/A Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =N/A N/A Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =5.00 5.00 feet Height of Vertical Curb Opening in Inches Hvert =6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat =6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5)Theta = 63.40 63.40 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.60 3.60 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = N/A N/A ft Depth for Curb Opening Weir Equation dCurb = 0.33 0.33 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.57 0.57 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 0.93 0.93 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = N/A N/A MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =10.5 10.5 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =1.6 6.8 cfs CDOT Type R Curb Opening INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type R Curb Opening Override Depths UD-Inlet.xlsm, Inlet 2 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK = Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =24.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX =0.050 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =24.0 24.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 3 UD-Inlet.xlsm, Inlet 3 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =N/A N/A feet Width of a Unit Grate Wo =N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =N/A N/A Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =N/A N/A Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =5.00 5.00 feet Height of Vertical Curb Opening in Inches Hvert =6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat =6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5)Theta = 63.40 63.40 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.60 3.60 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = N/A N/A ft Depth for Curb Opening Weir Equation dCurb = 0.33 0.33 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.57 0.57 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 0.93 0.93 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = N/A N/A MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =10.5 10.5 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.6 2.6 cfs CDOT Type R Curb Opening INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type R Curb Opening Override Depths UD-Inlet.xlsm, Inlet 3 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK = Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =60.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX =0.020 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =60.0 60.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 5a UD-Inlet.xlsm, Inlet 5a 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =N/A N/A feet Width of a Unit Grate Wo =N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =N/A N/A Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =N/A N/A Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =5.00 5.00 feet Height of Vertical Curb Opening in Inches Hvert =6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat =6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5)Theta = 63.40 63.40 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.60 3.60 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = N/A N/A ft Depth for Curb Opening Weir Equation dCurb = 0.33 0.33 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.57 0.57 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 0.93 0.93 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = N/A N/A MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =10.5 10.5 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.7 2.9 cfs CDOT Type R Curb Opening INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type R Curb Opening Override Depths UD-Inlet.xlsm, Inlet 5a 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK = Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =60.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX =0.025 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.016 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =60.0 60.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 5b UD-Inlet.xlsm, Inlet 5b 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =N/A N/A feet Width of a Unit Grate Wo =N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =N/A N/A Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =N/A N/A Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =5.00 5.00 feet Height of Vertical Curb Opening in Inches Hvert =6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat =6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5)Theta = 63.40 63.40 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.60 3.60 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = N/A N/A ft Depth for Curb Opening Weir Equation dCurb = 0.33 0.33 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.57 0.57 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 0.93 0.93 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = N/A N/A MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =10.5 10.5 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.7 2.9 cfs CDOT Type R Curb Opening INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type R Curb Opening Override Depths UD-Inlet.xlsm, Inlet 5b 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =7.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.020 ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.020 Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =95.0 ft Gutter Width W = 2.92 ft Street Transverse Slope SX =0.010 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =95.0 95.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 8.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 14 UD-Inlet.xlsm, Inlet 14 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =0.00 0.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 8.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =2.92 2.92 feet Width of a Unit Grate Wo =2.92 2.92 feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.70 0.70 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =2.41 2.41 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.67 0.67 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =N/A N/A feet Height of Vertical Curb Opening in Inches Hvert =N/A N/A inches Height of Curb Orifice Throat in Inches Hthroat =N/A N/A inches Angle of Throat (see USDCM Figure ST-5)Theta = N/A N/A degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =N/A N/A feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =N/A N/A Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =N/A N/A Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =N/A N/A Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = 0.379 0.545 ft Depth for Curb Opening Weir Equation dCurb = N/A N/A ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = N/A N/A Curb Opening Performance Reduction Factor for Long Inlets RFCurb = N/A N/A Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = 0.72 0.95 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =2.5 5.7 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =1.2 4.6 cfs CDOT Type C Grate INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type C Grate Override Depths UD-Inlet.xlsm, Inlet 14 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =20.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.010 ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.020 Height of Curb at Gutter Flow Line HCURB =0.00 inches Distance from Curb Face to Street Crown TCROWN =23.0 ft Gutter Width W = 2.92 ft Street Transverse Slope SX =0.010 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =22.0 23.0 ft Warning 02 Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 16 UD-Inlet.xlsm, Inlet 16 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =0.00 0.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 1 1 Water Depth at Flowline (outside of local depression)Ponding Depth = 5.2 5.3 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =2.92 2.92 feet Width of a Unit Grate Wo =2.92 2.92 feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.70 0.70 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =2.41 2.41 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.67 0.67 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =N/A N/A feet Height of Vertical Curb Opening in Inches Hvert =N/A N/A inches Height of Curb Orifice Throat in Inches Hthroat =N/A N/A inches Angle of Throat (see USDCM Figure ST-5)Theta = N/A N/A degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =N/A N/A feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =N/A N/A Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =N/A N/A Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =N/A N/A Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = 0.312 0.322 ft Depth for Curb Opening Weir Equation dCurb = N/A N/A ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = N/A N/A Curb Opening Performance Reduction Factor for Long Inlets RFCurb = N/A N/A Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = 0.82 0.84 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =1.3 1.4 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =0.3 1.3 cfs CDOT Type C Grate INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type C Grate Override Depths UD-Inlet.xlsm, Inlet 16 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =0.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK = Height of Curb at Gutter Flow Line HCURB =6.00 inches Distance from Curb Face to Street Crown TCROWN =50.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX =0.018 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =50.0 50.0 ft Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.0 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 17 UD-Inlet.xlsm, Inlet 17 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =3.00 3.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 6.0 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =N/A N/A feet Width of a Unit Grate Wo =N/A N/A feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =N/A N/A Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =N/A N/A Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =N/A N/A Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =N/A N/A Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =5.00 5.00 feet Height of Vertical Curb Opening in Inches Hvert =6.00 6.00 inches Height of Curb Orifice Throat in Inches Hthroat =6.00 6.00 inches Angle of Throat (see USDCM Figure ST-5)Theta = 63.40 63.40 degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =2.00 2.00 feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =0.10 0.10 Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =3.60 3.60 Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =0.67 0.67 Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = N/A N/A ft Depth for Curb Opening Weir Equation dCurb = 0.33 0.33 ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = 0.57 0.57 Curb Opening Performance Reduction Factor for Long Inlets RFCurb = 0.93 0.93 Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = N/A N/A MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =10.5 10.5 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =2.5 10.4 cfs CDOT Type R Curb Opening INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P CDOT Type R Curb Opening Override Depths UD-Inlet.xlsm, Inlet 17 4/11/2020, 3:18 PM Project: Inlet ID: Gutter Geometry (Enter data in the blue cells) Maximum Allowable Width for Spread Behind Curb TBACK =100.0 ft Side Slope Behind Curb (leave blank for no conveyance credit behind curb)SBACK =0.010 ft/ft Manning's Roughness Behind Curb (typically between 0.012 and 0.020)nBACK =0.016 Height of Curb at Gutter Flow Line HCURB =0.00 inches Distance from Curb Face to Street Crown TCROWN =30.0 ft Gutter Width W = 2.00 ft Street Transverse Slope SX =0.025 ft/ft Gutter Cross Slope (typically 2 inches over 24 inches or 0.083 ft/ft)SW =0.083 ft/ft Street Longitudinal Slope - Enter 0 for sump condition SO =0.000 ft/ft Manning's Roughness for Street Section (typically between 0.012 and 0.020)nSTREET =0.012 Minor Storm Major Storm Max. Allowable Spread for Minor & Major Storm TMAX =30.0 30.0 ft Warning 02 Max. Allowable Depth at Gutter Flowline for Minor & Major Storm dMAX =6.0 6.5 inches Check boxes are not applicable in SUMP conditions MINOR STORM Allowable Capacity is based on Depth Criterion Minor Storm Major Storm MAJOR STORM Allowable Capacity is based on Depth Criterion Qallow =SUMP SUMP cfs Version 4.05 Released March 2017 ALLOWABLE CAPACITY FOR ONE-HALF OF STREET (Minor & Major Storm) (Based on Regulated Criteria for Maximum Allowable Flow Depth and Spread) Larimer County Jail Inlet 19 UD-Inlet.xlsm, Inlet 19 4/11/2020, 3:18 PM Design Information (Input)MINOR MAJOR Type of Inlet Type = Local Depression (additional to continuous gutter depression 'a' from above)alocal =2.00 2.00 inches Number of Unit Inlets (Grate or Curb Opening)No = 2 2 Water Depth at Flowline (outside of local depression)Ponding Depth = 6.0 6.5 inches Grate Information MINOR MAJOR Length of a Unit Grate Lo (G) =3.00 3.00 feet Width of a Unit Grate Wo =1.73 1.73 feet Area Opening Ratio for a Grate (typical values 0.15-0.90)Aratio =0.31 0.31 Clogging Factor for a Single Grate (typical value 0.50 - 0.70)Cf (G) =0.50 0.50 Grate Weir Coefficient (typical value 2.15 - 3.60)Cw (G) =3.60 3.60 Grate Orifice Coefficient (typical value 0.60 - 0.80)Co (G) =0.60 0.60 Curb Opening Information MINOR MAJOR Length of a Unit Curb Opening Lo (C) =N/A N/A feet Height of Vertical Curb Opening in Inches Hvert =N/A N/A inches Height of Curb Orifice Throat in Inches Hthroat =N/A N/A inches Angle of Throat (see USDCM Figure ST-5)Theta = N/A N/A degrees Side Width for Depression Pan (typically the gutter width of 2 feet)Wp =N/A N/A feet Clogging Factor for a Single Curb Opening (typical value 0.10)Cf (C) =N/A N/A Curb Opening Weir Coefficient (typical value 2.3-3.7)Cw (C) =N/A N/A Curb Opening Orifice Coefficient (typical value 0.60 - 0.70)Co (C) =N/A N/A Low Head Performance Reduction (Calculated)MINOR MAJOR Depth for Grate Midwidth dGrate = 0.523 0.564 ft Depth for Curb Opening Weir Equation dCurb = N/A N/A ft Combination Inlet Performance Reduction Factor for Long Inlets RFCombination = N/A N/A Curb Opening Performance Reduction Factor for Long Inlets RFCurb = N/A N/A Grated Inlet Performance Reduction Factor for Long Inlets RFGrate = 0.71 0.76 MINOR MAJOR Total Inlet Interception Capacity (assumes clogged condition)Qa =4.1 5.0 cfs Inlet Capacity IS GOOD for Minor and Major Storms(>Q PEAK)Q PEAK REQUIRED =1.0 4.3 cfs Denver No. 16 Valley Grate INLET IN A SUMP OR SAG LOCATION Version 4.05 Released March 2017 H-VertH-Curb W Lo (C) Lo (G) Wo W P Denver No. 16 Valley Grate Override Depths UD-Inlet.xlsm, Inlet 19 4/11/2020, 3:18 PM 3130 Verona Avenue • Buford, GA 30518 (866) 888-8479 / (770) 932-2443 • Fax: (770) 932-2490 © Nyloplast Inlet Capacity Charts June 2012 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10Capacity (cfs)Head (ft) Nyloplast 24" Standard Grate Inlet Capacity Chart Number Series Manufacturer 1-877-903-7246 www.trenchdrainsupply.com Z882 Channel and Frame CPZ882 HDPE Channel Newmark Corporation T/A Trench Drain Supply - 5621 Raby Rd - Norfolk, Virginia 23502 - Phone 877-903-7246 - Fax 757-299-8059 - All Rights Reserved. DISCLAIMER - The customer and the customer’s architects, engineers, consultants, and other professionals are completely responsible for the selection installation and maintenance of any product purchased from Trench Drain Supply and/or its manufacturers. TRENCH DRAIN SUPPLY MAKES NO WARRANTY, EXPRESS OR IMPLIED, AS TO THE SUITABILITY, DESIGN, MERCHANTIBILITY, OR FITNESS OF THE PRODUCT FOR CUSTOMERS APPLICATION. The drawing and information provided remain the property and copyright of the manufacturer listed. The manufacturer reserves the right to modify specification without notice. Z882 Series APPENDIX H StormCAD Model for the Site Storm System Scenario: 100-yrCO-13CO-48CO-12CO-11CO-23(2)(1)CO-42CO-26CO-23(2)(2)C O -7 CO-43CO-6CO-23(1)CO-1(2)(2)CO-1(2)(1)CO-39CO-47C O -37CO-34CO-1(1)(1)(1)(1)(2)CO-1(1)(1)(1)(1)(1)CO-35CO-32CO-1(1)(1)(1)(2)CO-29(1)CO-1(1)(1)(2)CO-29(2)CO-1(1)(2)CO-31O-2O-1CB-32CB-37CB-2CB-1CB-18CB-31CB-30CB-16CB-36CB-7CB-6CB-4CB-27CB-26CB-35CB-25CB-24CB-34CB-39CB-21CB-20CB-23CB-12CB-11CB-10CB-9CB-3CB-38MH-53MH-35MH-11MH-10MH-9MH-65MH-7MH-5MH-26MH-45MH-3MH-2MH-24MH-63MH-22MH-62MH-20MH-59MH-39MH-38MH-55Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw Profile ReportEngineering Profile - STORM NORTH (StormCAD Model.stsw)4,900.004,905.004,910.00-0+500+000+501+001+502+002+503+00Rim: 4,910.57 ftInvert: 4,902.32 ftMH-38Rim: 4,909.36 ftInvert: 4,900.41 ftCB-16Rim: 4,909.21 ftInvert: 4,901.46 ftCB-35Rim: 4,908.32 ftInvert: 4,900.64 ftCO-23(2)(1): 64.9 ft @ 0.62 %Circle - 30.0 in ConcreteCO-43: 130.3 ft @ 0.51 %Circle - 24.0 in ConcreteCO-23(1): 84.6 ft @ 0.44 %Circle - 24.0 in ConcretePage 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw Profile ReportEngineering Profile - South Storm (StormCAD Model.stsw)4,895.004,900.004,905.004,910.00-0+500+000+501+001+502+002+503+003+504+004+50Station (ft)MH-7Rim: 4,907.75 ftInvert: 4,902.15 ftMH-5Rim: 4,907.30 ftInvert: 4,901.65 ftMH-26Rim: 4,908.55 ftInvert: 4,900.17 ftMH-3Rim: 4,906.45 ftInvert: 4,902.61 ftMH-2Rim: 4,908.64 ftInvert: 4,899.60 ftMH-24Rim: 4,908.34 ftInvert: 4,900.60 ftMH-22Rim: 4,908.09 ftInvert: 4,901.02 ftMH-20Rim: 4,907.55 ftInvert: 4,901.45 ftCO-1(2)(2): 71.6 ft @ 0.64 %Circle - 18.0 in ConcreteCO-1(2)(1): 77.9 ft @ 0.64 %Circle - 18.0 in ConcreteCO-1(1)(1)(1)(1)(2): 67.3 ft @ 0.64 %Circle - 24.0 in ConcreteCO-1(1)(1)(1)(1)(1): 58.1 ft @ 0.64 %Circle - 24.0 in ConcreteCO-1(1)(1)(1)(2): 65.7 ft @ 0.64 %Circle - 24.0 in ConcreteCO-1(1)(1)(2): 67.3 ft @ 0.64 %Circle - 18.0 in ConcreteCO-1(1)(2): 31.4 ft @ 0.64 %Circle - 18.0 in ConcretePage 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw Profile ReportEngineering Profile - Sally Port Storm (StormCAD Model.stsw)4,895.004,900.004,905.004,910.004,915.00-0+500+000+501+001+502+002+503+003+504+004+505+005+506+006+507+007+508+008+509+009+50Station (ft)MH-11Rim: 4,910.06 ftInvert: 4,904.19 ftMH-10Rim: 4,906.72 ftInvert: 4,901.88 ftMH-9Rim: 4,905.23 ftInvert: 4,900.72 ftMH-45Rim: 4,906.20 ftInvert: 4,900.50 ftMH-63Rim: 4,905.59 ftInvert: 4,899.52 ftMH-62Rim: 4,905.87 ftInvert: 4,900.02 ftCB-21Rim: 4,908.99 ftInvert: 4,904.78 ftO-1Rim: 4,905.40 ftInvert: 4,897.18 ftCO-33(2)(1): 165.8 ft @ 0.30 %Circle - 30.0 in ConcreteCO-7: 78.6 ft @ 0.50 %Circle - 24.0 in ConcreteCO-6: 105.5 ft @ 2.00 %Circle - 24.0 in ConcreteCO-5: 95.9 ft @ 1.00 %Circle - 24.0 in ConcreteCO-33(1): 160.0 ft @ 0.30 %Circle - 24.0 in ConcreteCO-32: 86.9 ft @ 0.25 %Circle - 24.0 in ConcreteCO-33(2)(2): 244.7 ft @ 0.96 %Circle - 30.0 in ConcretePage 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw Profile ReportEngineering Profile - STORM NORTH (StormCAD Model.stsw)4,900.004,905.004,910.00-0+500+000+501+001+502+002+503+00Rim: 4,910.57 ftInvert: 4,902.32 ftMH-38Rim: 4,909.36 ftInvert: 4,900.41 ftCB-16Rim: 4,909.21 ftInvert: 4,901.46 ftCB-35Rim: 4,908.32 ftInvert: 4,900.64 ftCO-23(2)(1): 64.9 ft @ 0.62 %Circle - 30.0 in ConcreteCO-43: 130.3 ft @ 0.51 %Circle - 24.0 in ConcreteCO-23(1): 84.6 ft @ 0.44 %Circle - 24.0 in ConcretePage 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw Profile ReportEngineering Profile - South Storm (StormCAD Model.stsw)4,895.004,900.004,905.004,910.00-0+500+000+501+001+502+002+503+003+504+004+50Station (ft)MH-7Rim: 4,907.75 ftInvert: 4,902.15 ftMH-5Rim: 4,907.30 ftInvert: 4,901.65 ftMH-26Rim: 4,908.55 ftInvert: 4,900.17 ftMH-3Rim: 4,906.45 ftInvert: 4,902.61 ftMH-2Rim: 4,908.64 ftInvert: 4,899.60 ftMH-24Rim: 4,908.34 ftInvert: 4,900.60 ftMH-22Rim: 4,908.09 ftInvert: 4,901.02 ftMH-20Rim: 4,907.55 ftInvert: 4,901.45 ftCO-1(2)(2): 71.6 ft @ 0.64 %Circle - 18.0 in ConcreteCO-1(2)(1): 77.9 ft @ 0.64 %Circle - 18.0 in ConcreteCO-1(1)(1)(1)(1)(2): 67.3 ft @ 0.64 %Circle - 24.0 in ConcreteCO-1(1)(1)(1)(1)(1): 58.1 ft @ 0.64 %Circle - 24.0 in ConcreteCO-1(1)(1)(1)(2): 65.7 ft @ 0.64 %Circle - 24.0 in ConcreteCO-1(1)(1)(2): 67.3 ft @ 0.64 %Circle - 18.0 in ConcreteCO-1(1)(2): 31.4 ft @ 0.64 %Circle - 18.0 in ConcretePage 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw Profile ReportEngineering Profile - Sally Port Storm (StormCAD Model.stsw)4,895.004,900.004,905.004,910.004,915.00-0+500+000+501+001+502+002+503+003+504+004+505+005+506+006+507+007+508+008+509+009+50Station (ft)MH-11Rim: 4,910.06 ftInvert: 4,904.19 ftMH-10Rim: 4,906.72 ftInvert: 4,901.88 ftMH-9Rim: 4,905.23 ftInvert: 4,900.72 ftMH-45Rim: 4,906.20 ftInvert: 4,900.50 ftMH-63Rim: 4,905.59 ftInvert: 4,899.52 ftMH-62Rim: 4,905.87 ftInvert: 4,900.02 ftCB-21Rim: 4,908.99 ftInvert: 4,904.78 ftO-1Rim: 4,905.40 ftInvert: 4,897.18 ftCO-33(2)(1): 165.8 ft @ 0.30 %Circle - 30.0 in ConcreteCO-7: 78.6 ft @ 0.50 %Circle - 24.0 in ConcreteCO-6: 105.5 ft @ 2.00 %Circle - 24.0 in ConcreteCO-5: 95.9 ft @ 1.00 %Circle - 24.0 in ConcreteCO-33(1): 160.0 ft @ 0.30 %Circle - 24.0 in ConcreteCO-32: 86.9 ft @ 0.25 %Circle - 24.0 in ConcreteCO-33(2)(2): 244.7 ft @ 0.96 %Circle - 30.0 in ConcretePage 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-16664/13/2020StormCAD CONNECT Edition[10.02.01.04]Bentley Systems, Inc. Haestad Methods Solution CenterStormCAD Model.stsw LabelCapacity (Full Flow) (cfs)Diameter (in)Energy Grade Line (In) (ft)Energy Grade Line (Out) (ft)Hydraulic Grade Line (In) (ft)Hydraulic Grade Line (Out) (ft)Flow (cfs)Invert (Start) (ft)Invert (Stop) (ft)Length (3D) (ft)Velocity (ft/s)Slope (Calculated) (%)CO-21.04 6 4,908.44 4,907.31 4,907.58 4,906.45 1.46 4,903.68 4,903.11 28.30 7.44 2.02CO-30.51 6 4,908.38 4,907.55 4,908.13 4,907.30 0.78 4,902.51 4,902.15 72.80 3.97 0.49CO-1(2)(1)8.42 18 4,907.40 4,907.34 4,907.36 4,907.30 2.92 4,902.15 4,901.65 77.90 1.65 0.64CO-1(2)(2)8.42 18 4,907.41 4,907.40 4,907.40 4,907.39 1.46 4,902.61 4,902.15 71.60 0.83 0.64CO-41.03 6 4,909.36 4,908.25 4,908.51 4,907.39 1.46 4,903.21 4,902.65 27.90 7.44 2.01CO-522.64 24 4,905.75 4,905.47 4,905.51 4,905.23 12.29 4,901.88 4,900.92 95.90 3.91 1.00CO-631.99 24 4,906.20 4,905.89 4,905.92 4,905.66 12.29 4,904.19 4,902.08 105.50 9.51 2.00CO-715.94 24 4,906.63 4,906.42 4,906.31 4,906.17 11.71 4,904.78 4,904.39 78.60 5.55 0.50CO-10(2)7.47 18 4,906.80 4,906.80 4,906.80 4,906.80 0.55 4,905.71 4,905.36 69.20 2.47 0.51CO-110.72 6 4,910.13 4,908.99 4,907.94 4,906.80 2.33 4,905.47 4,905.36 11.20 11.87 0.98CO-120.72 6 4,910.70 4,909.57 4,908.52 4,907.38 2.33 4,906.99 4,906.88 11.40 11.87 0.98CO-130.89 6 4,906.66 4,906.31 4,906.53 4,906.17 0.58 4,905.22 4,904.39 55.60 2.95 1.49CO-1(1)(2)8.39 18 4,907.66 4,907.62 4,907.59 4,907.55 3.70 4,901.65 4,901.45 31.40 2.09 0.64CO-141.03 6 4,909.74 4,908.52 4,908.77 4,907.55 1.55 4,902.49 4,901.95 27.10 7.89 1.99CO-1(1)(1)(2)8.4 18 4,907.82 4,907.66 4,907.69 4,907.52 5.25 4,901.45 4,901.02 67.30 2.97 0.64CO-156.52 12 4,907.59 4,907.56 4,907.55 4,907.52 1.29 4,901.77 4,901.06 35.80 1.64 1.98CO-1(1)(1)(1)(2)18.08 24 4,907.54 4,907.48 4,907.47 4,907.42 6.54 4,901.02 4,900.60 65.70 2.08 0.64CO-161.03 6 4,909.34 4,908.27 4,908.48 4,907.42 1.46 4,903.53 4,903.00 26.60 7.44 2.00CO-1(1)(1)(1)(1)(1)18.05 24 4,907.32 4,907.22 4,907.18 4,907.08 9.46 4,900.17 4,899.80 58.10 3.01 0.64CO-1(1)(1)(1)(1)(2)18.08 24 4,907.47 4,907.38 4,907.37 4,907.28 8.00 4,900.60 4,900.17 67.30 2.55 0.64CO-171.03 6 4,909.19 4,908.14 4,908.33 4,907.28 1.46 4,903.32 4,902.80 26.30 7.44 1.99CO-2445.51 36 4,907.19 4,906.87 4,906.82 4,906.50 34.33 4,899.60 4,899.03 122.40 4.86 0.47CO-23(1)14.96 24 4,908.51 4,908.15 4,908.17 4,907.81 14.71 4,901.46 4,901.09 84.60 4.68 0.44CO-23(2)(1)32.19 30 4,907.89 4,907.73 4,907.62 4,907.45 20.55 4,900.89 4,900.49 64.90 4.19 0.62CO-23(2)(2)45.83 36 4,907.51 4,907.27 4,907.32 4,907.08 24.87 4,900.41 4,899.60 171.50 3.52 0.47CO-2617.12 24 4,907.50 4,907.48 4,907.47 4,907.45 4.32 4,900.60 4,900.41 33.20 1.38 0.57CO-2710.9 21 4,907.60 4,907.54 4,907.55 4,907.49 4.32 4,901.31 4,900.90 86.60 1.8 0.47CO-307.41 18 4,907.26 4,907.18 4,907.11 4,907.08 3.75 4,906.13 4,905.91 44.30 4.21 0.50CO-310.17 4 4,910.93 4,909.52 4,909.69 4,908.28 0.78 4,902.58 4,902.51 14.10 8.94 0.50CO-29(1)7.26 18 4,906.98 4,906.86 4,906.86 4,906.74 4.85 4,905.43 4,905.15 58.70 4.4 0.48CO-29(2)7.43 18 4,907.11 4,907.01 4,906.97 4,906.92 4.30 4,905.81 4,905.53 53.40 4.36 0.50CO-3211.38 24 4,908.35 4,907.09 4,907.18 4,905.92 27.25 4,900.72 4,900.50 86.90 8.67 0.25CO-3416.39 24 4,905.91 4,905.58 4,905.56 4,905.23 14.96 4,901.11 4,900.72 74.30 4.76 0.52CO-3512.67 18 4,903.86 4,903.80 4,903.75 4,903.70 4.56 4,901.51 4,901.11 27.50 2.58 1.45CO-3736.91 36 4,986.79 4,986.52 4,986.43 4,986.15 34.33 4,898.90 4,898.58 104.50 4.86 0.31CO-380.17 4 4,911.64 4,911.24 4,910.40 4,910.00 0.78 4,902.60 4,902.58 3.90 8.94 0.50Conduit Flex Tables CO-391.5 8 4,908.63 4,908.49 4,907.32 4,907.18 3.20 4,906.26 4,906.23 3.40 9.17 0.91CO-410.84 6 4,906.79 4,906.77 4,906.65 4,906.63 0.58 4,905.26 4,905.22 3.00 2.95 1.33CO-427.41 18 4,908.94 4,908.82 4,908.80 4,908.68 5.28 4,902.75 4,902.52 40.70 2.99 0.50CO-4316.1 24 4,908.73 4,908.57 4,908.63 4,908.47 7.92 4,902.32 4,901.66 130.30 2.52 0.51CO-4415.64 24 4,908.70 4,908.69 4,908.68 4,908.68 2.64 4,902.63 4,902.52 32.90 0.84 0.48CO-33(1)12.39 24 4,906.15 4,903.83 4,904.98 4,902.66 27.25 4,900.50 4,900.02 79.00 8.67 0.30CO-33(2)(1)22.52 30 4,902.91 4,902.27 4,902.41 4,901.71 27.25 4,900.02 4,899.52 67.30 5.55 0.30CO-33(2)(2)40.11 30 4,902.13 4,899.89 4,901.30 4,898.69 27.25 4,899.52 4,897.18 46.60 8.78 0.96CO-10(1)(1)7.27 18 4,906.82 4,906.80 4,906.76 4,906.74 3.43 4,905.26 4,905.15 22.90 1.94 0.48CO-10(1)(2)16.58 24 4,906.81 4,906.79 4,906.64 4,906.63 8.83 4,905.05 4,904.98 13.00 5.36 0.54CO-468.04 18 4,909.02 4,909.01 4,908.88 4,908.87 5.28 4,902.98 4,902.95 7.70 2.99 0.59CO-472.53 12 4,908.97 4,908.84 4,908.90 4,908.76 1.76 4,904.76 4,904.48 60.20 2.24 0.50CO-482.46 12 4,908.85 4,908.84 4,908.78 4,908.76 1.76 4,907.40 4,907.37 18.80 2.24 0.48 APPENDIX I Low Impact Development Calculations and Rain Garden Design Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =100.0 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 1.000 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.40 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 84,750 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =2,825 cu ft Vol = (WQCV / 12) * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum)DWQCV =6 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 5.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin =1695 sq ft D) Actual Flat Surface Area AActual =4815 sq ft E) Area at Design Depth (Top Surface Area)ATop =7490 sq ft F) Rain Garden Total Volume VT=3,076 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =cu ft iii) Orifice Diameter, 3/8" Minimum DO = in Design Procedure Form: Rain Garden (RG) M/M May 22, 2020 Larimer County Jail Fort Collins, CO UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO 2020.05.22 - Updated UD-BMP_v3.07.xlsm, RG 5/22/2020, 9:43 AM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Control A) Inlet Control 7. Vegetation 8. Irrigation A) Will the rain garden be irrigated? Notes: Design Procedure Form: Rain Garden (RG) M/M May 22, 2020 Larimer County Jail Fort Collins, CO Choose One Choose One Choose One Sheet Flow- No Energy Dissipation Required Concentrated Flow- Energy Dissipation Provided Plantings Seed (Plan for frequent weed control) Sand Grown or Other High Infiltration Sod Choose One YES NO YES NO 2020.05.22 - Updated UD-BMP_v3.07.xlsm, RG 5/22/2020, 9:43 AM Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.011 Channel Slope 0.01750 ft/ft Normal Depth 1.00 ft Diameter 1.00 ft Results Discharge 5.57 ft³/s Flow Area 0.79 ft² Wetted Perimeter 3.14 ft Hydraulic Radius 0.25 ft Top Width 0.00 ft Critical Depth 0.94 ft Percent Full 100.0 % Critical Slope 0.01513 ft/ft Velocity 7.09 ft/s Velocity Head 0.78 ft Specific Energy 1.78 ft Froude Number 0.00 Maximum Discharge 5.99 ft³/s Discharge Full 5.57 ft³/s Slope Full 0.01750 ft/ft 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 Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Rain Garden to Pond 5/22/2020 12:56:16 PM Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page Q100 for Basin 18=21.88 cfs. There are four inlet within the Rain Garden. So, each must convey 5.47 cfs. 5.57 > 5.47, OK Evaluate the capacity of 12-inch dia. pipes to convey Q100 from Rain Garden to the detention pond. GVF Output Data Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.94 ft Channel Slope 0.01750 ft/ft Critical Slope 0.01513 ft/ft Rain Garden to Pond 5/22/2020 12:56:16 PM Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page 12" NYLOPLAST INLETSTORM CLEAN OUTSTORM CLEAN OUT12" NYLOPLAST INLET12" NYLOPLAST INLETSTORM CLEAN OUTSTORM CLEAN OUTTWO-WAY CLEANOUT12" NYLOPLAST INLETSTORM CLEAN OUTDISCHARGE AT GRADEWITH HEADWALLDISCHARGE AT GRADEWITH HEADWALLDISCHARGE AT GRADEWITH HEADWALLDISCHARGE AT GRADEWITH HEADWALL811””””RevisionsAttachment No. To: Dated: - N O T F O R CO N S T R U C T I O N - © DLR Group© DLR Group© DLR Group MARTIN/MARTIN C O N S U L T I N G E N G I N E E R S 12499 WEST COLFAX AVENUE, LAKEWOOD, COLORADO 80215 303.431.6100 MARTINMARTIN.COM05/15/2020LARIMER COUNTY JAILSITE PLAN REVIEW2405 MIDPOINT DRIVE, FORT COLLINS, CO 80525 IMPROVEMENTSRAIN GARDENPLANC550 Bioretention T-3 November 2010 Urban Drainage and Flood Control District B-13 Urban Storm Drainage Criteria Manual Volume 3 Table B-6. Native Seed Mix for Rain Gardens 2 1 Wildflower seed (optional) for a more diverse and natural look. 2 PLS = Pure Live Seed. Common Name Scientific Name Variety PLS2 lbs per Acre Ounces per Acre Sand bluestem Andropogon hallii Garden 3.5 Sideoats grama Bouteloua curtipendula Butte 3 Prairie sandreed Calamovilfa longifolia Goshen 3 Indian ricegrass Oryzopsis hymenoides Paloma 3 Switchgrass Panicum virgatum Blackwell 4 Western wheatgrass Pascopyrum smithii Ariba 3 Little bluestem Schizachyrium scoparium Patura 3 Alkali sacaton Sporobolus airoides 3 Sand dropseed Sporobolus cryptandrus 3 Pasture sage1 Artemisia frigida 2 Blue aster1 Aster laevis 4 Blanket flower1 Gaillardia aristata 8 Prairie coneflower1 Ratibida columnifera 4 Purple prairieclover1 Dalea (Petalostemum) purpurea 4 Sub-Totals: 27.5 22 Total lbs per acre: 28.9 APPENDIX J Drainage Plans 811EXISTINGDRAINAGE PLANC2501””””RevisionsAttachment No. To: Dated: - N O T F O R CO N S T R U C T I O N - © DLR Group© DLR Group© DLR Group MARTIN/MARTIN C O N S U L T I N G E N G I N E E R S 12499 WEST COLFAX AVENUE, LAKEWOOD, COLORADO 80215 303.431.6100 MARTINMARTIN.COM04/13/2020LARIMER COUNTY JAILSITE PLAN REVIEW2405 MIDPOINT DRIVE, FORT COLLINS, CO 80525 EXPANSION UP811””””PROPOSEDDRAINAGE PLANC251112RevisionsAttachment No. To: Dated: - N O T F O R CO N S T R U C T I O N - © DLR Group© DLR Group© DLR Group MARTIN/MARTIN C O N S U L T I N G E N G I N E E R S 12499 WEST COLFAX AVENUE, LAKEWOOD, COLORADO 80215 303.431.6100 MARTINMARTIN.COM04/13/2020LARIMER COUNTY JAILSITE PLAN REVIEW2405 MIDPOINT DRIVE, FORT COLLINS, CO 80525 EXPANSION MJJJUP36451518161789101112119213714811””””SITE PROPOSEDDRAINAGE PLANC2521RevisionsAttachment No. To: Dated: - N O T F O R CO N S T R U C T I O N - © DLR Group© DLR Group© DLR Group MARTIN/MARTIN C O N S U L T I N G E N G I N E E R S 12499 WEST COLFAX AVENUE, LAKEWOOD, COLORADO 80215 303.431.6100 MARTINMARTIN.COM04/13/2020LARIMER COUNTY JAILSITE PLAN REVIEW2405 MIDPOINT DRIVE, FORT COLLINS, CO 80525 EXPANSION APPENDIX K City of Fort Collins Standard Operating Procedures STANDARD OPERATING PROCEDURES (SOPs) A. Purpose In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential. Maintenance includes both routinely scheduled activities, as well as non- routine repairs that may be required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures (SOPs) clearly identify BMP maintenance responsibility. BMP maintenance is the responsibility of the entity owning the BMP. Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance is critical to the long-term success of BMPs. For this project, the privately owned BMPs shown in Section B below are to be maintained by the property owner or property manager. B. Site-Specific SOPs The following stormwater facilities contained within this development are subject to SOP requirements: - Directly Connected Downspouts - Perforated Subdrain - Storm Drain Lines - Dry Extended Detention - Pre-Sedimentation Forebay - Bioretention - Vegetated and/or Cobble Swale The location of said facilities can be found on the Larimer County Jail Utility Plans and Landscape Plans. Required inspection and specific maintenance procedures and frequencies are outlined in the following pages. General maintenance requirements and activities, as well as BMP-specific constraints and considerations shall follow the guidelines outlined in Volume 3 of the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual. SOP Maintenance Summary Table Stormwater Facility / BMP Ownership / Responsibility UDFCD Maintenance Reference Directly Connected Downspouts Private N/A Perforated Subdrain Private N/A Storm Drain Lines Private Follow guidelines for Storm Sewer System Cleaning (Chapter 5, Source Control BMP Fact Sheet S-12) Dry Extended Detention Private Follow guidelines for Extended Detention Basins (Chapter 6, Section 7.0) Pre-Sedimentation Forebay Private Follow guidelines for Pre-Sedimentation Forebay (Chapter 6, Section 9.0) Bioretention Private Follow guidelines for Bioretention (Chapter 6, Section 5.0) Vegetated and/or Cobble Swale Private Follow guidelines for Grass Buffers and Swales (Chapter 6, Section 4.0). Take note of native vegetation. Also follow recommendations on Landscape Plans and Specifications. Directly Connected Downspouts Many of the downspouts connect directly to the storm drain system. The following SOP generally applies to all direct downspout connections. This SOP can more specifically apply to those which drain directly to the reservoir areas beneath the Modular Block Pavers. At each of these connections, the downspout discharges to a perforated drain basin. The drain basins discharge directly to the MBP reservoir. The drain basins are designed to prevent debris and sediment from entering the MBP reservoir area. Debris and sediment compromise the functionality and effectiveness of the system. Routine Maintenance Table for Directly Connected Downspouts Required Action Maintenance Objective Frequency of Action Inspections Inspect the downspout and basin to ensure the system functions as it was designed. Repair or replace damaged downspouts as needed. Routine Sediment, Debris and Litter removal Remove debris and litter from the basin. Remove sediment from the sump. Routine – just before annual storm seasons (i.e., April/May); at the end of storm season after leaves have fallen; and following significant rainfall events. Perforated Subdrain The perforated subdrain system storm drain outfall at the bottom of the Low Impact Development (LID) system is critical to the overall function of the system subbase. As such, special maintenance has been identified to ensure these perforated drain systems perform as they were designed. Perforated subdrains leading away from the LID system is designed to provide faster release of water when accumulation occurs under the LID system. Outflow should be seen into downstream storm boxes. If not seen it is recommended that the system is inspected using a video camera to verify no clogging has occurred. Perforated subdrains leading toward the LID system are designed to provide an opportunity for infiltration. These subdrains may lead to a drywell where additional infiltration capacity is available to reduce runoff per the stated LID goals adopted by the City. Routine Maintenance Table Required Action Maintenance Objective Frequency of Action Inspection Use a video camera to inspect the condition of the perforated drain pipes. Cleanout pipes as needed. If the integrity of the pipe is compromised, then repair the damaged section(s). Every two to five years. Inspection Where accessible, expose inlet and/or outlet of perforated pipe and watch for water inflow and/or outflow. Minimum Annually Storm Drain Lines Maintenance Plan Storm drain lines are subject to sedimentation as well as tree roots clogging the flow path or altering the pipe slope. Maintenance is important to ensure these storm drain systems perform as they were designed. Routine Maintenance Table Required Action Maintenance Objective Frequency of Action Inspection Use a video camera to inspect the condition of the storm drain pipes. Cleanout pipes as needed. If the integrity of the pipe is compromised, then repair the damaged section(s). Every two to five years. Dry Extended Detention Basin Routine Maintenance Table (Summary from Chapter 6 of UDFCD) Required Action Maintenance Objective Frequency of Action Lawn mowing and Lawn care Occasional mowing to limit unwanted vegetation. Maintain irrigated turf grass as 2 to 4 inches tall and non- irrigated native turf grasses at 4 to 6 inches. Routine – Depending on aesthetic requirements. Sediment, Debris and Litter removal Remove sediment, debris and litter from the entire pond to minimize outlet clogging and improve aesthetics. Routine – Including just before annual storm seasons (that is, April and May), end of storm season after leaves have fallen, and following significant rainfall events. Major Pond Sediment removal Remove accumulated sediment from the bottom of the basin. Non-routine – Performed when sediment accumulation occupies 20 percent of the WQCV. This may vary considerably. Inspections required every 10 years, non- routine maintenance performed at that time if necessary. Typical is 10 – 20 years if no construction activities take place in the tributary watershed. Inspections Inspect basins to ensure that the basin continues to function as initially intended. Examine the outlet for clogging, erosion, slumping, excessive sedimentation levels, overgrowth, embankment and spillway integrity, and damage to any structural element. Routine – Annual inspection of hydraulic and structural facilities. Also check for obvious problems during routine maintenance visits, especially for plugging of outlets. Pre-Sedimentation Forebay Routine Maintenance Table (Summary from Chapter 6 of UDFCD) Required Action Maintenance Objective Frequency of Action Debris and Litter removal Remove debris and litter as needed. Floating debris can clog the overflow structure Routine – Including just before annual storm seasons (that is, April and May), end of storm season after leaves have fallen, and following significant rainfall events. Forebay Sediment removal Remove accumulated sediment from the bottom of the basin before it becomes a significant source of pollutants for the remainder of the pond. Inspect to ensure that sediment does not result in excessive algae growth or mosquito production. Non-routine – Performed when sediment accumulation appears to result in excessive algae growth or mosquito production. This may vary considerably, but expect to do this every approximately every 4 years, as necessary per inspection if no construction activities take place in the tributary watershed. More often if they do. Inspections Inspect to ensure that the facility continues to function as initially intended. Examine the outlet for clogging, erosion, slumping, excessive sedimentation levels, overgrowth, embankment integrity and damage to any structural element. Routine – Annual inspection of hydraulic and structural facilities. Also check for obvious problems during routine maintenance visits, especially for plugging of outlets. Note the amount of sediment in the forebay and look for debris at the outlet structure. Bioretention Routine Maintenance Table (Summary from Chapter 6 of UDFCD) Required Action Maintenance Objective Frequency of Action Lawn mowing and vegetative care Occasional mowing of grasses and weed removal to limit unwanted vegetation. Maintain irrigated turf grass as 2 to 4 inches tall and non- irrigated native turf grasses at 4 to 6 inches. Routine – Depending on aesthetic requirements, planting scheme and cover. Weeds should be removed before they flower. Debris and litter removal and snow stockpiling Remove debris and litter from bioretention area and upstream concrete forebay to minimize clogging of the sand media. Remove debris and litter from the pond area and outlet orifice plate to minimize clogging. Remove debris and litter from curb channel and sidewalk chase outlets adjacent to pond if applicable to minimize clogging. Avoid stockpiling snow in the bioretention area to minimize clogging from sediment accumulation. Routine – Including just before annual storm seasons and after snow season (April or May), end of storm season after leaves have fallen, and following significant rainfall events. Inspections Inspect detention area to determine if the sand media is allowing acceptable infiltration. If standing water persists for more than 24 hours after storm runoff has ceased, clogging should be further investigated and remedied. Routine – Biannual inspection of the hydraulic performance. Growing media replacement Restore infiltration capacity of bioretention facilities. Non-routine – Performed when clogging is due to the migration of sediments deep into the pore spaces of the media. The frequency of replacement will depend on site-specific pollutant loading characteristics. Vegetated and/or Cobble Swales Routine Maintenance Table (Summary from Table GS-1, Chapter 6 of UDFCD) Required Action Maintenance Objective Frequency of Action Lawn mowing and Lawn care Maintain irrigated grass at 2 to 4 inches tall and non-irrigated native grass at 6 to 8 inches tall. Collect cuttings and dispose of them offsite or use a mulching mower. Routine – As needed. Debris and Litter removal Keep the swale area clean for aesthetic reasons, which also reduces the potential for floatables being flushed downstream. Routine – As needed by inspection, but no less than two times per year. Sediment removal Remove accumulated sediment near culverts and in channels to maintain flow capacity. Replace the grass areas damaged in the process. Routine – As needed by inspection. Estimate the need to remove sediment from 3 to 10 percent of total length per year, as determined by annual inspection. Inspections Check the grass for uniformity of cover, sediment accumulation in the swale, and near culverts. Routine – Annual inspection is suggested. APPENDIX B WEB SOIL SURVEY Hydrologic Soil Group—Larimer County Area, Colorado8/29/20195/18/2021Page 1 of 4Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 40° 34' 10'' N 496400 496600 496800 497000 497200 497400 497600 497800 498000 40° 34' 10'' N Soil Map may not be valid at this scale. 40° 33' 31'' N 496400 496600 496800 497000 497200 497400 497600 497800 498000 40° 33' 31'' N Map Scale: 1:8,560 if printed on A landscape (11" x 8.5") sheet. N 0 100 200 400 Meters 600 Feet 0 400 800 1600 2400 Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 SITE4489900 4490100 4490300 4490500 4490700 4490900 105° 2' 40'' W 105° 2' 40'' W 105° 1' 21'' W 105° 1' 21'' W 4489900 4490100 4490300 4490500 4490700 4490900 Hydrologic Soil Group—Larimer County Area, Colorado8/29/20195/18/2021Page 2 of 4Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 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. 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: Larimer County Area, Colorado Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 11, 2018—Aug 12, 2018 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. 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. Hydrologic Soil Group—Larimer County Area, Colorado 8/29/2019Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/18/2021 Page 3 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 6 Aquepts, ponded A/D 5.5 1.5% 22 Caruso clay loam, 0 to 1 D 115.7 31.4% percent slope 42 Gravel pits A 18.2 4.9% 53 Kim loam, 1 to 3 percent slopes B 1.1 0.3% 54 Kim loam, 3 to 5 percent slopes B 5.0 1.3% 60 Larim gravelly sandy loam, 5 to 40 percent slopes B 1.9 0.5% 62 Larimer-Stoneham complex, 3 to 10 percent slopes B 19.4 5.3% 64 Loveland clay loam, 0 to C 79.7 21.6% 1 percent slopes 73 Nunn clay loam, 0 to 1 percent slopes C 40.0 10.8% 74 Nunn clay loam, 1 to 3 percent slopes C 1.3 0.4% 81 Paoli fine sandy loam, 0 to 1 percent slopes A 4.4 1.2% 92 Riverwash A 41.7 11.3% 101 Stoneham loam, 1 to 3 percent slopes B 2.6 0.7% 102 Stoneham loam, 3 to 5 percent slopes C 2.6 0.7% 105 Table Mountain loam, 0 to 1 percent slopes B 19.8 5.4% 136 Water 9.9 2.7% Totals for Area of Interest 368.5 100.0% Hydrologic Soil Group—Larimer County Area, Colorado 8/29/2019Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/18/2021 Page 4 of 4 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 Component Percent Cutoff: None Specified Tie-break Rule: Higher APPENDIX C CACHE LA POUDRE BASIN MAP FEMA FIRM MAP PROJECT SITE APPENDIX D HYDRAULIC COMPUTATIONS FOR SITE STORM SYSTEM Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 05 / 19 / 2021 Hyd. No. 9 Sub Basin CP1 Hydrograph type = Rational Peak discharge = 25.49 cfs Storm frequency = 2 yrs Time to peak = 9 min Time interval = 1 min Hyd. volume = 13,763 cuft Drainage area = 21.110 ac Runoff coeff. = 0.51 Intensity = 2.367 in/hr Tc by TR55 = 9.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 2 4 6 8 10 12 14 16 18 Q (cfs) 0.00 0.00 4.00 4.00 8.00 8.00 12.00 12.00 16.00 16.00 20.00 20.00 24.00 24.00 28.00 28.00 Q (cfs) Time (min) Sub Basin CP1 Hyd. No. 9 -- 2 Year Hyd No. 9 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Wednesday, 05 / 19 / 2021 Hyd. No. 9 Sub Basin CP1 Hydrograph type = Rational Peak discharge = 109.57 cfs Storm frequency = 100 yrs Time to peak = 9 min Time interval = 1 min Hyd. volume = 59,170 cuft Drainage area = 21.110 ac Runoff coeff. = 0.63 Intensity = 8.239 in/hr Tc by TR55 = 9.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 2 4 6 8 10 12 14 16 18 Q (cfs) 0.00 0.00 20.00 20.00 40.00 40.00 60.00 60.00 80.00 80.00 100.00 100.00 120.00 120.00 Q (cfs) Time (min) Sub Basin CP1 Hyd. No. 9 -- 100 Year Hyd No. 9 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 1 Sub Basin 1 Hydrograph type = Rational Peak discharge = 2.962 cfs Storm frequency = 2 yrs Time to peak = 3 min Time interval = 1 min Hyd. volume = 533 cuft Drainage area = 1.330 ac Runoff coeff. = 0.7* Intensity = 3.182 in/hr Tc by TR55 = 3.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 * Composite (Area/C) = [(0.440 x 0.20) + (0.890 x 0.95)] / 1.330 0 1 2 3 4 5 6 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (min) Sub Basin 1 Hyd. No. 1 -- 2 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 1 Sub Basin 1 Hydrograph type = Rational Peak discharge = 13.01 cfs Storm frequency = 100 yrs Time to peak = 3 min Time interval = 1 min Hyd. volume = 2,342 cuft Drainage area = 1.330 ac Runoff coeff. = 0.88* Intensity = 11.119 in/hr Tc by TR55 = 3.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 * Composite (Area/C) = [(0.440 x 0.20) + (0.890 x 0.95)] / 1.330 0 1 2 3 4 5 6 Q (cfs) 0.00 0.00 2.00 2.00 4.00 4.00 6.00 6.00 8.00 8.00 10.00 10.00 12.00 12.00 14.00 14.00 Q (cfs) Time (min) Sub Basin 1 Hyd. No. 1 -- 100 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 2 Sub Basin 2 Hydrograph type = Rational Peak discharge = 0.835 cfs Storm frequency = 2 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 100 cuft Drainage area = 0.260 ac Runoff coeff. = 0.95 Intensity = 3.383 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 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) Sub Basin 2 Hyd. No. 2 -- 2 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 2 Sub Basin 2 Hydrograph type = Rational Peak discharge = 3.047 cfs Storm frequency = 100 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 366 cuft Drainage area = 0.260 ac Runoff coeff. = 0.99 Intensity = 11.836 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 Q (cfs) Time (min) Sub Basin 2 Hyd. No. 2 -- 100 Year Hyd No. 2 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 3 Sub Basin 3 Hydrograph type = Rational Peak discharge = 0.353 cfs Storm frequency = 2 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 42 cuft Drainage area = 0.110 ac Runoff coeff. = 0.95 Intensity = 3.383 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 Q (cfs) Time (min) Sub Basin 3 Hyd. No. 3 -- 2 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 3 Sub Basin 3 Hydrograph type = Rational Peak discharge = 1.289 cfs Storm frequency = 100 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 155 cuft Drainage area = 0.110 ac Runoff coeff. = 0.99 Intensity = 11.836 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) Sub Basin 3 Hyd. No. 3 -- 100 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 4 Sub Basin 4 Hydrograph type = Rational Peak discharge = 0.418 cfs Storm frequency = 2 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 50 cuft Drainage area = 0.130 ac Runoff coeff. = 0.95 Intensity = 3.383 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 Q (cfs) Time (min) Sub Basin 4 Hyd. No. 4 -- 2 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 4 Sub Basin 4 Hydrograph type = Rational Peak discharge = 1.523 cfs Storm frequency = 100 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 183 cuft Drainage area = 0.130 ac Runoff coeff. = 0.99 Intensity = 11.836 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) Sub Basin 4 Hyd. No. 4 -- 100 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 5 Sub Basin 5 Hydrograph type = Rational Peak discharge = 0.032 cfs Storm frequency = 2 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 4 cuft Drainage area = 0.010 ac Runoff coeff. = 0.95 Intensity = 3.383 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04 0.05 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.10 0.10 Q (cfs) Time (min) Sub Basin 5 Hyd. No. 5 -- 2 Year Hyd No. 5 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 5 Sub Basin 5 Hydrograph type = Rational Peak discharge = 0.117 cfs Storm frequency = 100 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 14 cuft Drainage area = 0.010 ac Runoff coeff. = 0.99 Intensity = 11.836 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 Q (cfs) Time (min) Sub Basin 5 Hyd. No. 5 -- 100 Year Hyd No. 5 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 6 Sub Basin 6 Hydrograph type = Rational Peak discharge = 0.900 cfs Storm frequency = 2 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 108 cuft Drainage area = 0.280 ac Runoff coeff. = 0.95 Intensity = 3.383 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 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) Sub Basin 6 Hyd. No. 6 -- 2 Year Hyd No. 6 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 6 Sub Basin 6 Hydrograph type = Rational Peak discharge = 3.281 cfs Storm frequency = 100 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 394 cuft Drainage area = 0.280 ac Runoff coeff. = 0.99 Intensity = 11.836 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 Q (cfs) Time (min) Sub Basin 6 Hyd. No. 6 -- 100 Year Hyd No. 6 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 7 Sub Basin 7 Hydrograph type = Rational Peak discharge = 0.675 cfs Storm frequency = 2 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 81 cuft Drainage area = 0.210 ac Runoff coeff. = 0.95 Intensity = 3.383 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 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) Sub Basin 7 Hyd. No. 7 -- 2 Year Hyd No. 7 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 7 Sub Basin 7 Hydrograph type = Rational Peak discharge = 2.461 cfs Storm frequency = 100 yrs Time to peak = 2 min Time interval = 1 min Hyd. volume = 295 cuft Drainage area = 0.210 ac Runoff coeff. = 0.99 Intensity = 11.836 in/hr Tc by TR55 = 2.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (min) Sub Basin 7 Hyd. No. 7 -- 100 Year Hyd No. 7 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 8 Sub Basin 8 Hydrograph type = Rational Peak discharge = 0.514 cfs Storm frequency = 2 yrs Time to peak = 3 min Time interval = 1 min Hyd. volume = 92 cuft Drainage area = 0.170 ac Runoff coeff. = 0.95 Intensity = 3.182 in/hr Tc by TR55 = 3.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 5 6 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) Sub Basin 8 Hyd. No. 8 -- 2 Year Hyd No. 8 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2020 Tuesday, 05 / 18 / 2021 Hyd. No. 8 Sub Basin 8 Hydrograph type = Rational Peak discharge = 1.871 cfs Storm frequency = 100 yrs Time to peak = 3 min Time interval = 1 min Hyd. volume = 337 cuft Drainage area = 0.170 ac Runoff coeff. = 0.99 Intensity = 11.119 in/hr Tc by TR55 = 3.00 min IDF Curve = Ft Collins.IDF Asc/Rec limb fact = 1/1 0 1 2 3 4 5 6 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 Q (cfs) Time (min) Sub Basin 8 Hyd. No. 8 -- 100 Year Hyd No. 8 APPENDIX E STORM SEWER SYSTEM CAPACITY   STORM SEWER LAYOUT       Hydraflow Summary Report 1 Line No.Line ID Flow Rate Line Size (Rise x Span) Line Type Line Length Invert Elev. Down Invert Elev. Up Line Slope HGL Down HGL Up Minor Loss HGL Junct Dn Str Line No. (cfs)(in)(ft)(ft)(ft)(%)(ft)(ft)(ft)(ft) 1 Pipe 5 19.05 30 Cir 359.560 4898.36 4900.51 0.60 4900.82 4901.99 n/a 4901.99 j Outfall 2 Pipe 3 17.39 33 Cir 52.000 4900.52 4901.04 1.00 4901.99 4902.41 n/a 4902.41 j 1 3 Pipe 2 16.09 30 Cir 52.432 4901.14 4901.66 0.99 4902.41 4903.01 0.72 4903.01 2 4 Pipe 1 13.01 30 Cir 80.306 4901.76 4902.56 1.00 4903.01 4903.77 n/a 4903.77 j 3 5 Pipe 4 0.12 30 Cir 52.432 4900.52 4901.04 0.99 4901.99 4901.15 n/a 4901.15 1 Notes: j-Line contains hyd. jump   APPENDIX F DRAINAGE PLANS 49084909490849084 9 0 9 49 1 0 491049104909 490949104 9 1 1 49 1 1 4910 4909 4908 49 0 8 4 9 0 9 49104907 4908 4909 4910 4911 49084909491049104910491049 1 1 49 0 9 4910490849074907 4908 4909 4908.38 4907.88 4908.484908.73 4909.29 4909.00 4908.66 4908.78 4908.86 4908.974908.25 4908.144908.11 4908.224907.50 4907.63 4907.81 4907.97 4908.33 4908.44 4908.71 4908.93 4909.02 4909.16 4908.06 4908.69 4908.734908.26 4908.24 4906.69 4906.33 4906.90 4907.42 4907.95 4909.54 4909.54 4907.83 4907.83 4909.81 4909.64 4908.96 4908.41 4909.364909.91 4910.24 4910.55 4910.56 4910.544910.49 4910.79 4910.944910.51 4910.40 4910.30 4910.424909.55 4909.444909.34 4909.454908.80 4908.58 4908.45 4908.56 4908.67 4908.79 4908.84 4909.01 4909.38 4909.80 4909.63 4909.59 4909.91 4908.51 4908.19 4909.70 4909.80 4910.89 4910.73 4910.51 4910.25 4910.11 4910.44 4910.00 4909.60 4909.584909.98 4909.65 4911.85 4911.20 4910.72 4910.69 4910.61 4910.50 4910.38 4910.63 4911.19 4910.01 4909.88 4909.97 -1.2%-1.2%-1.7%-1.8%-2.0% -1.4% -2 . 3% -2.0%-1.4% -1.4%-2.1% -3.0%-2.7%-2.1%-2.3% -3.3%-1.2%-1.2%-0.7%-0.7%-0 .7% -3.1% -3.1%-2.0%-0.7%-0.9%-1.3%-2.2%-2.3% -1.4%-1.2%RECORD DRAWINGS FOR CONSTRUCTION FOR BID FOR PERMIT DESIGN IN PROGRESS DATE:FILE:SHEET NUMBER: ARCHITECT: CONSULTANT: PROJECT: OWNER: ARCHITECT PROJECT NO: SHEET TITLE: RELEASE FOR: SHEET RELEASE AND REVISION SCHEDULE: SEAL: DRAWN BY: CHECKED BY: PRELIMINARY DESIGN NOT FOR CONSTRUCTION \\avidc02fc\FDrive\0427 ASD Expansion\DESIGN\0427_Design.dwg5/19/2021 10:04:19 AM2307 MIDPOINT DRIVE FORT COLLINS, COLORADO 80525 Author Checker C1.6 GRADING PLAN ASD/COMCOR EXPANSION LARIMER COUNTY 200 WEST OAK STREET, SUITE 4000 FORT COLLINS, CO 80522 20-452 © Copyright The Architects' Studio, Inc. 405 MASON COURT, SUITE 115A FORT COLLINS, CO 80524 EXISTING ALTERNATIVE SENTENCING DETENTION BUILDING FF EL: 4913.0 ALTERNATIVE SENTENCING DETENTION BUILDING EXPANSION FF EL: 4913.0 EMERGENCY ACCESSTO MIDPOINT DRIVE00 30'60 SCALE 1" = 30' LEGEND FINISH GRADE CONTOURS 1' AND 5' FINISH GRADE CONTOUR ANNOTATION 1' AND 5' EXISTING CONTOURS EXISTING CONTOUR ANNOTATION PROPERTY BOUNDARY PROPOSED MANHOLE PROPOSED STORM SEWER PIPE PROPOSED INLET PROPOSED STORM SEWER FLARED END SECTION ST ST 49XX.XX 49XX.XX CONSTRUCTION NOTES: 1.SITE SUB-GRADE PREPARATION (EXCLUDING BUILDING) 1.1.ALL AREAS RECEIVING EITHER ASPHALT OR CONCRETE PAVEMENT SURFACING SHALL HAVE THE SUBGRADE MATERIALS OVER-EXCAVATED A DEPTH OF 3'. THE REMAINING MATERIAL AT A DEPTH OF 3' SHALL BE SCARIFIED 8", MOISTURE DENSITY CONTROL APPLIED, AND COMPACTED TO 95% OF ASTM D698. THE OVER-EXCAVATED MATERIAL SHALL THEN BE PLACED IN UNIFORM 8" THICK LIFTS, MOISTURE DENSITY CONTROL APPLIED, AND COMPACTED TO 95% OF ASTM D698. ALL OTHER AREAS WITH FLATWORK BEING PLACED, SHALL HAVE THE SUBGRADE SCARIFIED 8", MOISTURE DENSITY CONTROL APPLIED, AND COMPACTED TO 95% ASTM D698. 2.BEFORE AGGREGATE BASE IS INSTALLED, CHEMICALLY TREATED FLY ASH STABILIZATION SHALL BE APPLIED TO THE UPPER 12" OF SUBGRADE MATERIAL PER CDOT GUIDELINES. 3.ALL SPOT ELEVATIONS ARE FLOWLINE OF CURB UNLESS OTHERWISE NOTED. 4.HANDICAP RAMPS SHALL NOT EXCEED 8.33% SLOPE (1:12). SIDEWALKS IN GENERAL SHALL NOT EXTEED 5.00% SLOPE UNLESS NECESSARY IN WHICH HANDICAP RAMPS SHALL NOT EXCEED 8.33% SLOPE. 5.SIDEWALKS SHALL BE PLACED AT A GRADE AS TO ALLOW SHEET FLOW SHEET FLOW DRAINAGE OVER THE TOP. 6.MINIMUM - THE FINISH GRADE SHALL SLOPE AWAY FROM THE BUILDING AT A MINIMUM OF 2% TOWARDS SWALES OR OVER CURB TO PAVED AREA. 7.ALL CONSTRUCTION SHALL BE IN ACCORDANCE WITH LCUASS STANDARD SPECIFICATIONS LATEST VERSION, CDOT STANDARD SPECIFICATIONS FOR ROAD AND BRIDGE CONSTRUCTION LATEST VERSION, AND THE PROJECT SPECIFICATIONS. 8.MAX SLOPE AT HANDICAPPED PARKING STALLS IS 2% IN ANY DIRECTION. 9.CONTRACTOR SHALL VERIFY EXISTING ELEVATIONS SHOWN AT TIE POINTS. CONTRACTOR TO NOTIFY ENGINEER IF ELEVATIONS VARY FROM THAT SHOWN ON THE PLANS. 10.CONTRACTOR SHALL ADJUST STORM GRATES, VALVES, ELECTRICAL BOXES, ETC. AS NECESSARY TO PROPOSED TOP OF GRADE IN ACCORDANCE WITH THE PROJECT SPECIFICAIONS. *CONTRACTOR SHALL CONSULT THE GEOTECHNICAL INVESTIGATIVE REPORT BEFORE OVERLOT GRADING, SUB-GRADE PREPARATION, AND FINAL SURFACING WORK COMMENCES. *CONTRACTOR SHALL VERIFY EXISTING AND ADJACENT PROPOSED ELEVATIONS SHOWN AT TIE POINTS. CONTRACTOR SHALL NOTIFY ENGINEER IF ELEVATIONS VARY FROM THAT SHOWN ON THE PLANS AND/OR IF TIE-IN LOCATIONS APPEAR TO CAUSE LOW POINTS IN CURB LINES. 6' CONCRETE VALLEY PAN 188' LONG 23' 2' WIDE CURB CUT TO DRAIN INTO BIOSWALE LOW IMPACT DEVELOPMENT LOCATION 171' 8' LOW IMPACT DEVELOPMENT LOCATION EXISTING DRIVE RECORD DRAWINGS FOR CONSTRUCTION FOR BID FOR PERMIT DESIGN IN PROGRESS DATE:FILE:SHEET NUMBER: ARCHITECT: CONSULTANT: PROJECT: OWNER: ARCHITECT PROJECT NO: SHEET TITLE: RELEASE FOR: SHEET RELEASE AND REVISION SCHEDULE: SEAL: DRAWN BY: CHECKED BY: PRELIMINARY DESIGN NOT FOR CONSTRUCTION F:\0427 ASD Expansion\DESIGN\Drainage exhibit.dwg2307 MIDPOINT DRIVE FORT COLLINS, COLORADO 80525 Author Checker SB.1 ADDITIONAL IMPERVIOUS & PERVIOUS AREAS ASD/COMCOR EXPANSION LARIMER COUNTY 200 WEST OAK STREET, SUITE 4000 FORT COLLINS, CO 80522 20-452 © Copyright The Architects' Studio, Inc. 405 MASON COURT, SUITE 115A FORT COLLINS, CO 80524 AREA=10,725 SF AREA=48,697 SF AREA=8,910 SF AREA=541 SF AREA=631 SF AREA=8,911 SF ADDED IMPERVIOUS AREAS TOTALING: 69,505 SF (1.60 AC) ADDED PERVIOUS AREAS TOTALING: 10,670 SF (0.24 AC) AREA=1,250 SF PARKING AREA PROPOSED BUILDING EXPANSION AREA=510SF NET INCREASE IN IMPERVIOUS AREAS: 1.36 ACRES LEGEND STSTST RECORD DRAWINGS FOR CONSTRUCTION FOR BID FOR PERMIT DESIGN IN PROGRESS DATE:FILE:SHEET NUMBER: ARCHITECT: CONSULTANT: PROJECT: OWNER: ARCHITECT PROJECT NO: SHEET TITLE: RELEASE FOR: SHEET RELEASE AND REVISION SCHEDULE: SEAL: DRAWN BY: CHECKED BY: PRELIMINARY DESIGN NOT FOR CONSTRUCTION F:\0427 ASD Expansion\DESIGN\Drainage exhibit.dwg2307 MIDPOINT DRIVE FORT COLLINS, COLORADO 80525 Author Checker SB.2 ADDITIONAL IMPERVIOUS & PERVIOUS AREAS ASD/COMCOR EXPANSION LARIMER COUNTY 200 WEST OAK STREET, SUITE 4000 FORT COLLINS, CO 80522 20-452 © Copyright The Architects' Studio, Inc. 405 MASON COURT, SUITE 115A FORT COLLINS, CO 80524 SUB BASIN TOTALING: 919,552 SF (21.11 AC) DRAINAGE FLOW PATH PROPOSED BUILDING EXPANSION LEGEND SUB BASIN CP1 919,552 SF RECORD DRAWINGS FOR CONSTRUCTION FOR BID FOR PERMIT DESIGN IN PROGRESS DATE:FILE:SHEET NUMBER: ARCHITECT: CONSULTANT: PROJECT: OWNER: ARCHITECT PROJECT NO: SHEET TITLE: RELEASE FOR: SHEET RELEASE AND REVISION SCHEDULE: SEAL: DRAWN BY: CHECKED BY: PRELIMINARY DESIGN NOT FOR CONSTRUCTION F:\0427 ASD Expansion\DESIGN\Drainage exhibit.dwg2307 MIDPOINT DRIVE FORT COLLINS, COLORADO 80525 Author Checker SB.3 ADDITIONAL IMPERVIOUS & PERVIOUS AREAS ASD/COMCOR EXPANSION LARIMER COUNTY 200 WEST OAK STREET, SUITE 4000 FORT COLLINS, CO 80522 20-452 © Copyright The Architects' Studio, Inc. 405 MASON COURT, SUITE 115A FORT COLLINS, CO 80524 SUB BASIN 2 11,274 SF SUB BASINS TOTALING: 109,245 SF (2.51 AC) DRAINAGE FLOW PATH PROPOSED BUILDING EXPANSION LEGEND SUB BASIN 1 58,129 SF SUB BASIN 3 4,759 SF SUB BASIN 4 5,868 SF SUB BASIN 5 295 SF SUB BASIN 6 12,288 SF SUB BASIN 8 7,306 SF SUB BASIN 7 9,326 SF APPENDIX G CITY OF FORT COLLINS STANDARD OPERATING PROCEDURES STANDARD OPERATING PROCEDURES (SOPs) A. Purpose In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential. Maintenance includes both routinely scheduled activities, as well as non- routine repairs that may be required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures (SOPs) clearly identify BMP maintenance responsibility. BMP maintenance is the responsibility of the entity owning the BMP. Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance is critical to the long-term success of BMPs. For this project, the privately owned BMPs shown in Section B below are to be maintained by the property owner or property manager. B. Site-Specific SOPs The following stormwater facilities contained within this development are subject to SOP requirements: - Directly Connected Downspouts - Perforated Subdrain - Storm Drain Lines - Dry Extended Detention - Pre-Sedimentation Forebay - Bioretention - Vegetated and/or Cobble Swale The location of said facilities can be found on the ASD/COMCOR Expansion Plans and Landscape Plans. Required inspection and specific maintenance procedures and frequencies are outlined in the following pages. General maintenance requirements and activities, as well as BMP-specific constraints and considerations shall follow the guidelines outlined in Volume 3 of the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual. SOP Maintenance Summary Table Stormwater Facility / BMP Ownership / Responsibility UDFCD Maintenance Reference Directly Connected Downspouts Private N/A Perforated Subdrain Private N/A Storm Drain Lines Private Follow guidelines for Storm Sewer System Cleaning (Chapter 5, Source Control BMP Fact Sheet S-12) Dry Extended Detention Pre-Sedimentation Forebay Private Follow guidelines for Extended Detention Basins (Chapter 6, Section 7.0) Private Follow guidelines for Pre-Sedimentation Forebay (Chapter 6, Section 9.0) Bioretention Private Follow guidelines for Bioretention (Chapter 6, Section 5.0) Follow guidelines for Grass Buffers and Swales Vegetated and/or Cobble Swale Private (Chapter 6, Section 4.0). Take note of native vegetation. Also follow recommendations on Landscape Plans and Specifications. Directly Connected Downspouts Many of the downspouts connect directly to the storm drain system. The following SOP generally applies to all direct downspout connections. This SOP can more specifically apply to those which drain directly to the reservoir areas beneath the Modular Block Pavers. At each of these connections, the downspout discharges to a perforated drain basin. The drain basins discharge directly to the MBP reservoir. The drain basins are designed to prevent debris and sediment from entering the MBP reservoir area. Debris and sediment compromise the functionality and effectiveness of the system. Required Action Routine Maintenance Table for Directly Connected Downspouts Maintenance Objective Frequency of Action Inspect the downspout and basin to Inspections Sediment, Debris and Litter removal ensure the system functions as it was designed. Repair or replace damaged downspouts as needed. Remove debris and litter from the basin. Remove sediment from the sump. Routine Routine – just before annual storm seasons (i.e., April/May); at the end of storm season after leaves have fallen; and following significant rainfall events. P Perforated Subdrain The perforated subdrain system storm drain outfall at the bottom of the Low Impact Development (LID) system is critical to the overall function of the system subbase. As such, special maintenance has been identified to ensure these perforated drain systems perform as they were designed. Perforated subdrains leading away from the LID system is designed to provide faster release of water when accumulation occurs under the LID system. Outflow should be seen into downstream storm boxes. If not seen it is recommended that the system is inspected using a video camera to verify no clogging has occurred. Perforated subdrains leading toward the LID system are designed to provide an opportunity for infiltration. These subdrains may lead to a drywell where additional infiltration capacity is available to reduce runoff per the stated LID goals adopted by the City. Routine Maintenance Table Required Action Maintenance Objective Frequency of Action Use a video camera to inspect the condition of the perforated drain Inspection Inspection pipes. Cleanout pipes as needed. If the integrity of the pipe is compromised, then repair the damaged section(s). Where accessible, expose inlet and/or outlet of perforated pipe and watch for water inflow and/or outflow. Every two to five years. Minimum Annually Storm Drain Lines Maintenance Plan Storm drain lines are subject to sedimentation as well as tree roots clogging the flow path or altering the pipe slope. Maintenance is important to ensure these storm drain systems perform as they were designed. Required Action Routine Maintenance Table Maintenance Objective Frequency of Action Use a video camera to inspect the condition of the storm drain pipes. Inspection Cleanout pipes as needed. If the integrity of the pipe is compromised, then repair the damaged section(s). Every two to five years.