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HomeMy WebLinkAboutREGISTRY RIDGE SEVENTH FILING, REPLAT OF FILINGS TWO & FOUR - PDP - PDP140020 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORT1501 Academy Ct. Ste. 203 Fort Collins, Colorado 80524 (970) 530-4044 Preliminary Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO Prepared for: RC Ventures, LLC 10221 Prestwick Trail Lone Tree, CO 80124 November 20, 2014 Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 1 U14012-DrainageAddendum-Prelminary.doc November 20, 2014 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Registry Ridge Seventh Filing Fort Collins, Colorado Project Number: U14012 Dear Staff: United Civil Design Group, LLC. is pleased to submit this Prelminary Drainage Addendum for the Registry Ridge Seventh Filing site in Fort Collins, Colorado. In general, this summary serves to document the stormwater impacts associated with the proposed project and to verify that the project does conform to the intent and requirements set forth in the following approved final drainage reports: • “Final Drainage Report for Registry Ridge P.U.D., Second Filing”, prepared by TST, Inc. and dated November 6, 2000. • “Drainage Design Considerations for Registry Ridge P.U.D., Fourth Filing”, by Northern Engineering Services, Inc. and dated December 5, 2001. Site Location and Project Description The Registry Ridge Seventh Filing development site (referred herein as ”the site”) is located in the northeast quarter of Section 15, Township 6 North, Range 69 West of the Sixth P.M., City of Fort Collins, Larimer County, Colorado and consists of portions of two (2) previous filings of the subdivision, the Second Filing north of Bon Homme Richard Drive and the Fourth Filing south of Bon Homme Richard Drive. The site has a platted area of 11.83 acres and is bounded by South Shields Street to the east, Truxon Drive to the north, and Registry Ridge First and Third Filings to the west and south. See the attached Drainage Plan for additional information. The planned development is separated into three distinct areas separated by existing public right-of way. For clarity, the three development areas are designated as the “Northeast Area”, North Central Area”, and “South Area” within this report. In total, the development will consist of the following: • Twenty-eight (28) single family duplex buildings with fifty-six (56) total units. • Eighteen (18) single family detached lots. • A public roadway and private drives in support of the development. • The construction of utilities to support the development including sanitary, water and storm drainage. Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 2 U14012-DrainageAddendum-Prelminary.doc Existing Conditions Hydrology The site, which is located within the Fossil Creek Drainage Basin, is divided into three areas that are separated by existing roadways. Each area is described as follows: Northeast Area The northeast area consists of 1.41 acres and is covered with grasses and weeds. The area has been previously overlot graded and currently drains from west to east towards South Shields Street. Ultimately, the Second Filing shows that a portion of the site will continue drain to Shields Street with the remainder being graded towards Enterprise Drive to the east where runoff will be intercepted by existing storm drainage and conveyed to the existing water quality and detention pond located south of the development. North Central Area The north central area consists of 2.72 acres and is currently adjacent to active construction and is being utilized as a construction staging area. The area has been previously overlot graded and currently drains from west to east towards Enterprise Drive. Ultimately, the Second Filing shows that the site will continue drain to Enterprise Drive to the east where runoff will be intercepted by existing storm drainage and conveyed to the existing water quality and detention pond located south of the development. South Area The south area consists of 8.15 acres and is covered with grasses and weeds. The area has been previously overlot graded and currently drains from north to south towards the existing water quality and detention pond located south of the development. Floodplain The site is not located within a FEMA or City-regulatory floodway or floodplain. The nearest City-regulatory high risk floodway is located south of the site within the existing detention pond area. No improvements are being proposed within this area. Detention The regional detention pond located just south of the development provides both detention and water quality for the site and is not being modified with this project. Developed Conditions In part, the intent of this Drainage Addendum is to verify that the Seventh Filing project conforms to the intent and requirements set forth in the previous drainage reports for this site. As such, the following sections of this Addendum compare the proposed design for the Seventh Filing to the design as shown in aforementioned reports for both the Second and Fourth Filings. Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 3 U14012-DrainageAddendum-Prelminary.doc Hydrology Northeast Area Basin A as shown in the attached Drainage Plan contains the entirety of the northeast area of the development. The majority of the basin is collected via streets and storm sewer and routed to the regional pond south of the site, matching the drainage patterns set forth in the Second Filing report. The following table compares the characteristics of Basin A to the same area as shown in the drainage report for the Second Filing: Comparison Summary Table Basin A Second Filing Overall Area (acres) 1.41 1.41 Impervious Area (acres) 0.55 0.71 % Imperviousness 37% 47% Area Draining to Shields (acres) 0.63 0.55 As shown in the above table, the proposed improvements for the Seventh Filing result in lower impervious areas from those shown in the approved TST report. In addition, the drainage patterns as shown in the Second Filing report have remained largely unchanged. Therefore, the proposed Seventh Filing improvements for the northeast area appear to meet the intent and requirements set forth in the original TST report and it is anticipated that the Seventh Filing improvements will not have a negative impact to the existing downstream drainage facilities. North Central Area Basin B as shown in the attached Drainage Plan contains the entirety of the north central area of the development. The entirety of the basin is collected via streets and storm sewer and routed to the regional pond south of the site, matching the drainage patterns set forth in the Second Filing report. The following table compares the characteristics of Basin B to the same area as shown in the drainage report for the Second Filing: Comparison Summary Table Basin B Second Filing Overall Area (acres) 2.27 2.27 Impervious Area (acres) 1.26 1.41 % Imperviousness 52% 58% Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 4 U14012-DrainageAddendum-Prelminary.doc As shown in the above table, the proposed improvements for the Seventh Filing result in lower impervious areas from those shown in the approved TST report. In addition, the drainage patterns as shown in the Second Filing report have remained largely unchanged. Therefore, the proposed Seventh Filing improvements for the north central area appear to meet the intent and requirements set forth in the original TST report and it is anticipated that the Seventh Filing improvements will not have a negative impact to the existing downstream drainage facilities. South Area Basin C as shown in the attached Drainage Plan contains the entirety of the south area of the development. The entirety of the basin is collected via swales, streets, and storm sewer and routed to the regional pond south of the site, matching the drainage patterns set forth in the Second Filing report. The following table compares the characteristics of Basin C to the same area as shown in the drainage report for the Fourth Filing: Comparison Summary Table Basin C Fourth Filing Overall Area (acres) 8.15 8.15 Impervious Area (acres) 3.74 3.91 % Imperviousness 41% 45% As shown in the above table, the proposed improvements for the Seventh Filing result in lower impervious areas from those shown in the approved Northern Engineering report. In addition, the drainage patterns as shown in the Fourth Filing report have remained largely unchanged. Therefore, the proposed Seventh Filing improvements for the northeast area appear to meet the intent and requirements set forth in the original Northern Engineering report and it is anticipated that the Seventh Filing improvements will not have a negative impact to the existing downstream drainage facilities. Storm Sewer Storm Sewer Line 1 is located in the northeast area of the proposed development and collects runoff from Basin A3. This storm line has been added in order to minimize the amount of runoff being released to South Shields Street and to help minimize the amount of fill required for the area. The storm line will connect to the existing 30-inch storm drain on the south end of the site which is the same system the runoff draining to Enterprise Drive enters (Basins A1 and A2). Storm Sewer Line 2 is located in the north central area of the proposed development and collects runoff from Basin B1. The storm line will connect to the existing 30-inch Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 5 U14012-DrainageAddendum-Prelminary.doc storm drain on the north end of the site which is the same system the runoff drains to in the Second Filing report. Storm Sewer Lines 3-4 are located in the south area of the proposed development and collect runoff from Basins C2-C6. In order to eliminate as much surface water as possible through Basin C6 due to erosion concerns, Storm Line 4 will be designed to convey the 100-year flows away from the site and into the downstream porous landscape detention (PLD) area being designed with this project. Storm line 3 is the outlet system from the PLD pond to the existing detention pond south of the development. Storm Sewer Line 5 is located in the south area of the proposed development and collects runoff from Basin C8 and the underdrain for the permeable pavers being designed for the private drive within the basin. The storm line will discharge runoff into the existing drainage swale on the south side of the property which delivers runoff to the existing detention pond. Detention and Water Quality Requirements As previously mentioned, the site is provided with detention and water quality from the regional pond just south of the site. With the Seventh Filing development not exceeding the assumptions made during the design of the regional facility, no further detention or water quality improvements are required with the Seventh Filing. Low Impact Development (LID) Requirements In February of 2013, City Council adopted the LID policy and criteria. The Seventh Filing of Registry Ridge is required to meet the newly adopted criteria. Per the criteria, the site must: • Treat no less than 50% of any newly added impervious area using one or a combination of LID techniques. • Treat no less than 25% of any newly added pavement area using a permeable pavement. The northeast and north central areas of the development are located within previously approved developments and are now considered “infill” sites as infrastructure improvements for these areas area complete. Due to this, and in communication with City personnel, the north areas of the development will not be treated with LID techniques. The south area of the development will be treated with various LID techniques and the overall treatment of the project will be as close to 50% as feasible; however, per communication with City personnel, the 50% requirement will not be strictly enforced due to the portions of the site unavailable for treatment. Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 6 U14012-DrainageAddendum-Prelminary.doc The following measures are being implemented within the south area of the proposed development: Porous Landscape Detention (PLD) Basins C2-C6 (with 2.04 acres of impervious area) will be routed through a PLD being designed with this project. The PLD has an average depth of 8-inches (12- inches maximum) with an overall volume of 4,429 cubic feet which exceeds the minimum design requirements for the area. Refer to the Appendix for additional PLD calculations. Permeable Pavers Basin C8 (with 0.512 acres of impervious area) will be routed over permeable pavers being designed within the private drive within the basin. The pavers will be designed with an underdrain that terminates at a proposed storm inlet at Storm Line 5. The development has a total of 0.70 acres of pavement being designed within private drives for the development. The permeable paver area totals 0.20 acres, or 28.6% of the total private pavement area for the project. In total, the south area is proposing to collect and treat 2.56 acres (46.0%) of the overall 5.56 acres of impervious area developed with this project. In addition, the site is also being designed with other various open landscaped areas, grass buffers and vegetated swales to provide additional water quality above the areas being treated with the PLD or permeable pavers. Four Step Process With the adoption of the USDCM, the City has also adopted the “Four Step Process” that is recommended in Volume 3 of the USDCM in selecting structural BMPs for the redeveloping urban areas. The following portions of this addendum describe each step and how it has been utilized for this project: Step 1 – Employ Runoff Reduction Practices The objective of this step is to reduce runoff peaks and volumes and to employ the technique of “minimizing directly connected impervious areas” (MDCIA). This project accomplishes this by: • Providing grass buffers throughout the site between impervious areas to minimize directly connected impervious areas. • Routing flows through a series of vegetated swales to increase time of concentration, promote infiltration and provide initial water quality. • Routing portions of the site through a PLD or permeable pavers to promote infiltration and provide additional water quality. Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 7 U14012-DrainageAddendum-Prelminary.doc Step 2 – Provide Water Quality Capture Volume (WQCV) The objective of providing WQCV is to reduce the sediment load and other pollutants that exit the site. For this project WQCV is provided within the regional pond located south of the site, so no additional WQCV is required. However, the development is providing a PLD, and therefore, additional WQCV in order to satisfy the LID requirements. Step 3 – Stabilize Drainageways The site is adjacent to an existing drainage channel south of the development. The project is not directly stabilizing this manmade drainageway; however, the project is indirectly maintaining the existing stability of the drainageway by directing the vast majority of onsite flows away from the channel and to the existing regional pond south of the site. Additionally, this project will pay stormwater development and stormwater utility fees which the City uses, in part, to maintain the stability of the City drainageway systems. Step 4 – Consider Need for Industrial and Commercial BMPs This step is generally considered for industrial and commercial sites. As this development is proposing single family dwellings only, no specialized BMPs have been considered for this project. Standard Operating Procedures (SOPs) 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 should clearly identify BMP maintenance responsibility. BMP maintenance is typically 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. Maintenance responsibility may be assigned either publicly or privately. For this project, the privately owned BMPs shown in the PDP drawings are to be maintained by the property owner, homeowner’s association (HOA), or property manager. Erosion Control This PDP submittal includes a preliminary Erosion Control Plan. The final submittal will include a comprehensive Erosion Control Plan with construction details as well as a comprehensive Erosion Control Report. Drainage Addendum Registry Ridge Seventh Filing Fort Collins, CO 8 U14012-DrainageAddendum-Prelminary.doc Conclusions In conclusion, the drainage system proposed within this Drainage Addendum provides adequate conveyance of the developed stormwater runoff from the proposed development to existing discharge locations and drainage systems. In addition, the calculations provided show that the proposed drainage system does meet the intent and requirements set forth in the original drainage reports for both the Second and Fourth Filings of Registry Ridge. It should also be noted that with this addendum and the corresponding design, every attempt has been made to minimize any negative impacts on the downstream receiving waters. With the incorporation of the LID techniques, the site will discharge a lower sediment load and less runoff than the design originally proposed with the Second and Fourth Registry Ridge projects. We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This addendum was prepared in compliance with technical criteria set forth in both the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the FCSCM. If you should have any questions or comments as you review this drainage summary, please feel free to contact us at your convenience. Sincerely, United Civil Design Group, LLC Kevin Brazelton, PE Engineering Manager APPENDICES APPENDIX A - Hydrology Computations APPENDIX B - Water Quality Calculations APPENDIX C - Hydraulic Computations (Reserved for future submittal) C.1 – Storm Pipe Calculations (Reserved for future submittal) C.2 – Inlet Sizing Calculations (Reserved for future submittal) C.3 – Riprap Sizing Calculations (Reserved for future submittal) C.4 – Pond Weir Calculations (Reserved for future submittal) APPENDIX D - Standard Operating Procedures (Reserved for future submittal) APPENDIX E – Referenced Material APPENDIX F - Drainage Exhibit APPENDIX A Hydrology Calculations Registry Ridge Seventh Filing Fort Collins, CO Runoff Summary Area Q2 Q100 (acre) (cfs) (cfs) A1 A1 0.17 49% 0.62 0.78 0.30 1.29 A2 A2 0.43 52% 0.64 0.80 0.79 3.45 A3 A3 0.19 54% 0.65 0.81 0.34 1.50 A4 A4 0.63 18% 0.38 0.48 0.68 2.98 B1 B1 0.14 2% 0.25 0.31 0.10 0.45 B2 B2 0.85 58% 0.68 0.85 1.66 7.24 B3 B3 0.43 50% 0.62 0.77 0.75 3.29 B4 B4 0.84 56% 0.68 0.84 1.44 6.27 1D 1D 0.51 69% 0.76 0.95 1.09 4.77 1E 1E 0.09 48% 0.62 0.77 0.15 0.67 C1 C1 0.62 46% 0.59 0.74 0.75 3.29 C2 C2 0.45 57% 0.67 0.84 0.87 3.78 C3 C3 0.34 59% 0.69 0.86 0.66 2.89 C4 C4 1.14 52% 0.64 0.79 2.07 9.02 C5 C5 0.97 60% 0.69 0.86 1.90 8.31 C6 C6 0.91 33% 0.50 0.62 1.29 5.63 C7 C7 0.31 39% 0.55 0.68 0.35 1.53 C8 C8 0.82 40% 0.55 0.69 1.30 5.66 C9 C9 0.86 36% 0.52 0.65 1.27 5.55 C10 C10 0.71 29% 0.47 0.59 0.95 4.13 C11 C11 0.88 22% 0.41 0.51 1.03 4.47 C12 C12 0.13 2% 0.25 0.31 0.09 0.38 Onsite Total 11.83 43% 0.56 0.70 18.58 81.10 Existing Basins -Adjacent to North Central Site Proposed Basins -South Site Proposed Basins -North Central Site Proposed Basins -Northeast Site C C100 Basin Design Point %I 2 Calculations by: KRB Date: 11/12/2014 D:\Dropbox\Projects\U14012 - Liberty Ridge\Drainage\Hydrology\Runoff (Fort Collins).xlsx Registry Ridge Seventh Filing Fort Collins, CO Previous Study Site Runoff Coefficients and % Impervious Roof (1) Concrete(1) Asphalt(1) Permeable Pavers Landscape(1) %I = 90% %I = 90% %I =100% %I=22% %I=2% C = 0.95 C = 0.95 C = 0.95 C = 0.40 C = 0.25 acres sf sf sf sf sf sf C2 C100 Northeast Site Tract B 1.413 61571 19080 4705 7145 0 30641 47% 0.60 0.75 Northeast Total 1.413 61571 19080 4705 7145 0 30641 47% 0.60 0.75 North Central Site Tract A 2.272 98960 37855 6230 17295 0 37580 58% 0.68 0.86 North Cemtral Total 2.272 98960 37855 6230 17295 0 37580 58% 0.68 0.86 South Site Enitre Fourth Filing 8.146 354840 54540 73445 42430 0 184425 45% 0.59 0.73 South Total 8.146 354840 54540 73445 42430 0 184425 45% 0.59 0.73 Notes: (1) Recommended % Imperviousness Values from USDCM Vol 1 - Ch 5 - Table RO-3. Increased Lawns from 0% to 2% Impervious. (2) Runoff C2 is based on UDFCD Eq RO-8 per City Amendment to Chapter 5. Runoff C100 is based upon Table RO-12 per City Amendment to Chapter 5. (3) Basin designations and impervious areas taken from Second Filing report by TST and Fourth Filing report by Northern Engineering. Basin Design Pt. Areas Composite Imperviousness (%I) Composite Runoff Total Total Coefficients (2) Calculations by: KRB Date: 11/12/2014 D:\Dropbox\Projects\U14012 - Liberty Ridge\Drainage\Hydrology\Runoff (Fort Collins).xlsx Registry Ridge Seventh Filing Fort Collins, CO Runoff Coefficients and % Impervious Roof (1) Concrete(1) Asphalt(1) Permeable Pavers Landscape(1) %I = 90% %I = 90% %I =100% %I=22% %I=2% C = 0.95 C = 0.95 C = 0.95 C = 0.40 C = 0.25 acres sf sf sf sf sf sf C2 C100 Proposed Basins -Northeast Site A1 A1 0.167 7280 2350 1500 0 0 3430 49% 0.62 0.78 A2 A2 0.432 18812 4700 3603 2222 0 8287 52% 0.64 0.80 A3 A3 0.186 8081 1575 1450 1611 0 3446 54% 0.65 0.81 A4 A4 0.629 27398 3126 1995 0 0 22278 18% 0.38 0.48 Northeast Total 1.413 61571 11750 8548 3833 0 37440 37% 0.52 0.66 Proposed Basins -North Central Site B1 B1 0.144 6281 0 0 0 0 6281 2% 0.25 0.31 B2 B2 0.854 37201 8813 7166 6953 0 14270 58% 0.68 0.85 B3 B3 0.429 18696 2350 3645 3777 0 8924 50% 0.62 0.77 B4 B4 0.844 36782 12338 8681 1321 0 14443 56% 0.68 0.84 North Cemtral Total 2.272 98960 23500 19492 12051 0 43917 52% 0.64 0.80 Existing Basins -Adjacent to North Central Site (3) 1D(3) 1D(3) 0.507 22065 7930 1433 6607 0 6095 69% 0.76 0.95 1E(3) 1E(3) 0.088 3822 1197 814 0 0 1811 48% 0.62 0.77 Proposed Basins -South Site C1 C1 0.619 26985 5288 5342 2599 0 13757 46% 0.59 0.74 C2 C2 0.454 19774 4700 3551 3613 0 7910 57% 0.67 0.84 C3 C3 0.339 14768 3525 2688 2966 0 5589 59% 0.69 0.86 Composite Runoff Basin Coefficients (2) Areas Composite Imperviousness (%I) Design Total Total Pt. Calculations by: KRB Date: 11/12/2014 D:\Dropbox\Projects\U14012 - Liberty Ridge\Drainage\Hydrology\Runoff (Fort Collins).xlsx Registry Ridge Seventh Filing Fort Collins, CO Runoff Coefficients and % Impervious C4 C4 1.142 49749 10575 7188 9613 0 22373 52% 0.64 0.79 C5 C5 0.971 42285 7638 8629 10214 0 15805 60% 0.69 0.86 C6 C6 0.908 39561 8225 5801 0 0 25535 33% 0.50 0.62 C7 C7 0.313 13636 3525 2250 0 0 7861 39% 0.55 0.68 C8 C8 0.822 35804 7638 6015 0 8762 13390 40% 0.55 0.69 C9 C9 0.856 37286 8813 5625 0 0 22849 36% 0.52 0.65 C10 C10 0.709 30884 5875 3750 0 0 21259 29% 0.47 0.59 C11 C11 0.882 38424 5288 3375 0 0 29762 22% 0.41 0.51 C12 C12 0.130 5684 0 0 0 0 5684 2% 0.25 0.31 South Total 8.146 354840 71088 54214 29005 8762 191772 41% 0.55 0.69 Onsite Total 11.831 515371 106338 82254 44889 8762 273129 43% 0.56 0.70 Notes: (1) Recommended % Imperviousness Values from USDCM Vol 1 - Ch 5 - Table RO-3. Increased Lawns from 0% to 2% Impervious. (2) Runoff C2 is based on UDFCD Eq RO-8 per City Amendment to Chapter 5. Runoff C100 is based upon Table RO-12 per City Amendment to Chapter 5. (3) Existing basins adjacent to North Central site that drain through the proposed site. Basin designations and impervious areas taken from Second Filing report by TST. Calculations by: KRB Date: 11/12/2014 D:\Dropbox\Projects\U14012 - Liberty Ridge\Drainage\Hydrology\Runoff (Fort Collins).xlsx Registry Ridge Seventh Filing Fort Collins, CO Time of Concentration Area Length Slope ti (2) Length Slope Velocity (3) t t (4) Check tc? Total Length t c (5) acres ft % min ft % fps min min u = urban ft min min Proposed Basins -Northeast Site A1 A1 0.17 Roof 0.73 20 2 2.4 85 2 20 2.8 0.5 2.9 u 105 11 5 A2 A2 0.43 Roof 0.73 20 2 2.4 95 2 20 2.8 0.6 2.9 u 115 11 5 A3 A3 0.19 Roof 0.73 20 2 2.4 50 2 20 2.8 0.3 2.7 u 70 10 5 A4 A4 0.63 Roof 0.73 40 2 3.4 105 5.5 20 4.7 0.4 3.7 u 145 11 5 Proposed Basins -North Central Site B1 B1 0.14 Roof 0.73 17 1.6 2.4 56 0.6 20 1.5 0.6 3.0 u 73 10 5 B2 B2 0.85 Roof 0.73 20 2 2.4 240 1.41 20 2.4 1.7 4.1 u 260 11 5 B3 B3 0.43 Roof 0.73 30 2 2.9 205 1.82 20 2.7 1.3 4.2 u 235 11 5 B4 B4 0.84 Roof 0.73 20 2 2.4 560 0.94 20 1.9 4.8 7.2 u 580 13 7 Existing Basins -Adjacent to North Central Site 1D 1D 0.51 Roof 0.73 20 2 2.4 170 1.5 20 2.4 1.2 3.5 u 190 11 5 1E 1E 0.09 Roof 0.73 20 2 2.4 25 2 20 2.8 0.1 2.5 u 45 10 5 Proposed Basins -South Site C1 C1 0.62 Lawn 0.09 46 1.76 10.2 343 0.57 20 1.5 3.8 14.0 u 389 12 12 C2 C2 0.45 Roof 0.73 20 2 2.4 240 1 20 2.0 2.0 4.4 u 260 11 5 C3 C3 0.34 Roof 0.73 20 2 2.4 202 1.05 20 2.0 1.6 4.0 u 222 11 5 C4 C4 1.14 Roof 0.73 20 2 2.4 295 1.5 20 2.4 2.0 4.4 u 315 12 5 C5 C5 0.97 Roof 0.73 20 2 2.4 400 1.16 20 2.2 3.1 5.5 u 420 12 5 C6 C6 0.91 Roof 0.73 20 2 2.4 295 1.34 20 2.3 2.1 4.5 u 315 12 5 C7 C7 0.31 Lawn 0.09 85 1.45 14.8 223 1.54 20 2.5 1.5 16.3 u 308 12 12 C8 C8 0.82 Roof 0.73 20 2 2.4 350 1.83 20 2.7 2.2 4.5 u 370 12 5 C9 C9 0.86 Roof 0.73 20 2 2.4 75 4.81 20 4.4 0.3 2.7 u 95 11 5 C10 C10 0.71 Roof 0.73 20 2 2.4 125 4.1 20 4.0 0.5 2.9 u 145 11 5 C11 C11 0.88 Roof 0.73 20 2 2.4 345 3.2 20 3.6 1.6 4.0 u 365 12 5 C12 C12 0.13 Roof 0.73 40 0.5 5.3 215 2.6 20 3.2 1.1 6.4 u 255 11 6 Notes: (1) C5 based initial ground type and Table RO-5 (4) tt=L/(V*60 sec/min) (2) ti = [1.8(1.1-C 5)L 1/2 ]/S 1/3 , S= slope in %, L=length of overland flow (400' max) (5) tc check (for urban or developed areas only) = total length/180 + 10 (3) V=CvS 0.5 Registry Ridge Seventh Filing Fort Collins, CO Rational Method Peak Runoff Final tc (6) I 2 I100 Q2 Q 100 acres min in/hr in/hr cfs cfs Proposed Basins -Northeast Site A1 A1 0.167 5 0.62 0.78 2.85 9.95 0.295 1.289 A2 A2 0.432 5 0.64 0.80 2.85 9.95 0.790 3.446 A3 A3 0.186 5 0.65 0.81 2.85 9.95 0.344 1.503 A4 A4 0.629 5 0.38 0.48 2.85 9.95 0.683 2.979 Proposed Basins -North Central Site B1 B1 0.144 5 0.25 0.31 2.85 9.95 0.103 0.448 B2 B2 0.854 5 0.68 0.85 2.85 9.95 1.659 7.239 B3 B3 0.429 5 0.62 0.77 2.85 9.95 0.753 3.288 B4 B4 0.844 7 0.68 0.84 2.52 8.80 1.437 6.271 Existing Basins -Adjacent to North Central Site 1D 1D 0.507 5 0.76 0.95 2.85 9.95 1.092 4.767 1E 1E 0.088 5 0.62 0.77 2.85 9.95 0.155 0.675 Proposed Basins -South Site C1 C1 0.619 12 0.59 0.74 2.05 7.16 0.753 3.289 C2 C2 0.454 5 0.67 0.84 2.85 9.95 0.867 3.783 C3 C3 0.339 5 0.69 0.86 2.85 9.95 0.662 2.889 C4 C4 1.142 5 0.64 0.79 2.85 9.95 2.068 9.023 C5 C5 0.971 5 0.69 0.86 2.85 9.95 1.904 8.311 C6 C6 0.908 5 0.50 0.62 2.85 9.95 1.289 5.627 C7 C7 0.313 12 0.55 0.68 2.05 7.16 0.351 1.531 C8 C8 0.822 5 0.55 0.69 2.85 9.95 1.297 5.660 C9 C9 0.856 5 0.52 0.65 2.85 9.95 1.271 5.547 C10 C10 0.709 5 0.47 0.59 2.85 9.95 0.946 4.128 C11 C11 0.882 5 0.41 0.51 2.85 9.95 1.025 4.474 C12 C12 0.130 6 0.25 0.31 2.67 9.31 0.087 0.380 Onsite Total 11.831 18.584 81.105 Design Pt. Peak Discharge Area Basin Runoff Coefficients Rainfall Intensity C2 C 100 Calculations by: KRB Date: 11/12/2014 D:\Dropbox\Projects\U14012 - Liberty Ridge\Drainage\Hydrology\Runoff (Fort Collins).xlsx APPENDIX B Water Quality Calculations Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia = 50.7 % (100% if all paved and roofed areas upstream of rain garden) B) Tributary Area's Imperviousness Ratio (i = Ia/100) i = 0.507 C) Water Quality Capture Volume (WQCV) for a 12-hour Drain Time WQCV = 0.17 watershed inches (WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including rain garden area) Area = 166,138 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV = 2,306 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, VWQCVOTHER = cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCVUSER = cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth (12-inch maximum) DWQCV = 8 in B) Rain Garden Side Slopes (Z = 4 min., horiz. dist per unit vertical) Z = 4.00 ft / ft (Use "0" if rain garden has vertical walls) C) Mimimum Flat Surface Area AMin = 1537 sq ft D) Actual Flat Surface Area AActual = 4703 sq ft E) Area at Design Depth (Top Surface Area) ATop = 6589 sq ft F) Rain Garden Total Volume VT= 3,792 cu ft (VT= ((ATop + AActual) / 2) * Depth) 3. Growing Media 4. Underdrain System A) Are underdrains provided? 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 = N/A cu ft iii) Orifice Diameter, 3/8" Minimum DO = N/A in Design Procedure Form: Rain Garden (RG) KRB United Civil November 12, 2014 Registry Ridge Seventh Filing Fort Collins Choose One Choose One 18" Rain Garden Growing Media Other (Explain): YES NO UD-BMP_v3.03.xlsm, RG 11/12/2014, 11:27 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) KRB United Civil November 12, 2014 Registry Ridge Seventh Filing Fort Collins 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 UD-BMP_v3.03.xlsm, RG 11/12/2014, 11:27 AM STAGE STORAGE TABLE - East Side of PLD ELEV AREA (sq. ft.) DEPT H (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) CONIC INC. VOL. (cu. ft.) CONIC TOTAL VOL. (cu. ft.) 5,063.200 973.07 N/A N/A 0.00 N/A 0.00 5,063.300 1,970.22 0.100 147.16 147.16 144.26 144.26 5,063.400 2,727.37 0.100 234.88 382.04 233.86 378.12 5,063.500 2,819.08 0.100 277.32 659.37 277.31 655.43 5,063.600 2,911.84 0.100 286.55 945.91 286.53 941.96 5,063.700 3,005.71 0.100 295.88 1241.79 295.86 1237.83 5,063.800 3,100.83 0.100 305.33 1547.12 305.31 1543.14 5,063.900 3,197.33 0.100 314.91 1862.02 314.90 1858.04 5,064.000 3,295.23 0.100 324.63 2186.65 324.62 2182.65 5,064.100 3,394.51 0.100 334.49 2521.14 334.47 2517.13 STAGE STORAGE TABLE - West Side of PLD ELEV AREA (sq. ft.) DEPTH (ft) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) CONIC INC. VOL. (cu. ft.) CONIC TOTAL VOL. (cu. ft.) 5,063.200 491.08 N/A N/A 0.00 N/A 0.00 5,063.300 1,072.05 0.100 78.16 78.16 76.29 76.29 5,063.400 1,617.81 0.100 134.49 212.65 133.56 209.85 5,063.500 2,069.78 0.100 184.38 397.03 183.92 393.77 5,063.600 2,358.28 0.100 221.40 618.43 221.25 615.01 5,063.700 2,454.79 0.100 240.65 859.09 240.64 855.65 5,063.800 2,546.72 0.100 250.08 1109.16 250.06 1105.71 5,063.900 2,639.81 0.100 259.33 1368.49 259.31 1365.03 5,064.000 2,734.32 0.100 268.71 1637.20 268.69 1633.72 5,064.100 2,830.13 0.100 278.22 1915.42 278.21 1911.93 APPENDIX C Hydraulic Calculations (Reserved for future submittal) APPENDIX D Standard Operating Procedures (Reserved for future submittal) APPENDIX E Referenced Material This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-27-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-21-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-21-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-21-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA This unofficial copy was downloaded on Oct-21-2014 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com For additional information or an official copy, please contact City of Fort Collins Utilities 700 Wood Street Fort Collins, CO 80524 USA APPENDIX F Drainage Exhibit A4 A1 C8 C3 C4 C5 C6 C9 S8 C7 C11 C10 C12 HORNET DRIVE ENTERPRISE DRIVE PRIVATE DRIVE PRIVATE DRIVE NIMITZ DRIVE PRIVATE DRIVE PRIVATE DRIVE PRIVATE DRIVE PROPOSED STORM DRAIN LINE 5 POROUS LANDSCAPE DETENTION PROPOSED STORM DRAIN LINE 1 PROPOSED STORM INLET PROPOSED STORM INLETS PROPOSED STORM INLET POROUS LANDSCAPE DETENTION CURB CUT AND SIDEWALK CHASE CURB CUT AND SIDEWALK CHASE PROPOSED STORM DRAIN LINE 4 CURB CUT AND SIDEWALK CHASE PROPOSED POND OUTLET STRUCTURE CURB CUT AND SIDEWALK CHASE PERMEABLE PAVERS WITH UNDERDRAIN CITY HIGH RISK FLOODWAY PROPOSED STORM DRAIN LINE 2 PROPOSED STORM DRAIN LINE 3 PREPARED FOR: DATE SUBMITTED: The engineer preparing these plans will not be responsible for, or liable for, unauthorized changes to or uses of these plans. All changes to the plans must be in writing and must be approved by the preparer of these plans. CAUTION CITY OF FORT COLLINS 11/20/14 U14012 PRELIMINARY PLANS NOT FOR CONSTRUCTION 1501 Academy Ct. Ste. 203 Fort Collins, CO 80524 (970) 530-4044 www.unitedcivil.com Civil Engineering & Consulting REGISTRY RIDGE SEVENTH FILING DRAINAGE PLAN C800 N/A CHECKED BY: 60' CHECKED BY: CHECKED BY: CHECKED BY: CHECKED BY: APPROVED: 00 60' 120' SCALE: 1" = 60' 30' 1. EXISTING UNDERGROUND AND OVERHEAD PUBLIC AND PRIVATE UTILITIES AS SHOWN ARE INDICATED ACCORDING TO THE BEST INFORMATION AVAILABLE TO THE ENGINEER. 2. VEGETATIVE SWALES, PERMEABLE PAVERS AND THE POROUS LANDSCAPE DETENTION SHALL BE MAINTAINED BY THE PROPERTY OWNER OR HOA AND FOLLOW APPLICABLE STANDARD OPERATING PROCEDURES AS SHOWN IN DRAINAGE REPORT FOR REGISTRY RIDGE SEVENTH FILING. LEGEND NOTES D-101 BASIN DESIGNATION BASIN AREA (ACRE) 2 - YR RUNOFF COEFF. 100 - YR RUNOFF COEFF. BASIN BOUNDARY DESIGN POINT FLOW DIRECTION DRAINAGE SUMMARY Basin Design Point Area %I C2 C100 Q2 Q100 (acre) (cfs) (cfs) Proposed Basins -Northeast Site A1 A1 0.17 49% 0.62 0.78 0.30 1.29 A2 A2 0.43 52% 0.64 0.80 0.79 3.45 A3 A3 0.19 54% 0.65 0.81 0.34 1.50 A4 A4 0.63 18% 0.38 0.48 0.68 2.98 Proposed Basins -North Central Site B1 B1 0.14 2% 0.25 0.31 0.10 0.45 B2 B2 0.85 58% 0.68 0.85 1.66 7.24 B3 B3 0.43 50% 0.62 0.77 0.75 3.29 B4 B4 0.84 56% 0.68 0.84 1.44 6.27 Existing Basins -Adjacent to North Central Site 1D 1D 0.51 69% 0.76 0.95 1.09 4.77 1E 1E 0.09 48% 0.62 0.77 0.15 0.67 Proposed Basins -South Site C1 C1 0.62 46% 0.59 0.74 0.75 3.29 C2 C2 0.45 57% 0.67 0.84 0.87 3.78 C3 C3 0.34 59% 0.69 0.86 0.66 2.89 C4 C4 1.14 52% 0.64 0.79 2.07 9.02 C5 C5 0.97 60% 0.69 0.86 1.90 8.31 C6 C6 0.91 33% 0.50 0.62 1.29 5.63 C7 C7 0.31 39% 0.55 0.68 0.35 1.53 C8 C8 0.82 40% 0.55 0.69 1.30 5.66 C9 C9 0.86 36% 0.52 0.65 1.27 5.55 C10 C10 0.71 29% 0.47 0.59 0.95 4.13 C11 C11 0.88 22% 0.41 0.51 1.03 4.47 C12 C12 0.13 2% 0.25 0.31 0.09 0.38 Onsite Total 11.83 43% 0.56 0.70 18.58 81.10 , S=watercourse slope in ft/ft, UDFCD Equation RO-4 (6) min tc = 5 min Initial Ground Type C5 (1) C v ti+tt Final tc (6) tc Check for Urbanized Basin Initial Overland Flow Time (ti) Travel/Channelized Time of Flow (tt) Design Pt. Calculations by: KRB Date: 11/12/2014 D:\Dropbox\Projects\U14012 - Liberty Ridge\Drainage\Hydrology\Runoff (Fort Collins).xlsx