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HomeMy WebLinkAboutALPINE BANK - PDP200020 - - DRAINAGE REPORT PREPARED FOR: Alpine Bank 220 Grand Avenue Glenwood Springs, CO 81601 Phone: (970) 384-3209 PREPARED BY: Galloway & Company, Inc. 6162 S. Willow Drive, Suite 320 Greenwood Village, CO 80111 Phone: (303) 770-8884 DATE: December 2, 2020 REVISED: ALPINE BANK SUBDIVISION ALPINE BANK Fort Collins, Colorado PRELIMINARY DRAINAGE REPORT Galloway & Company, Inc. Page 2 of 20 6162 S. Willow Drive, Suite 320 Greenwood Village, CO 80111 303.770.8884 • GallowayUS.com Galloway & Company, Inc. Page 3 of 20 6162 S. Willow Drive, Suite 320 Greenwood Village, CO 80111 303.770.8884 • GallowayUS.com PRELIMINARY DRAINAGE REPORT Alpine Bank Subdivision Alpine Bank Legal Description A portion of Lots 1, 2, 3, 4, 5, and 6, I.C. Bradley’s Addition to the City of Fort Collins; Part of the Northwest ¼ of Section 24, Township 7 North, Range 69 West, of the 6th P.M., City of Fort Collins, County of Larimar, State of Colorado. Preparation Date December 2, 2020 Revised Date Prepared for Alpine Bank 220 Grand Avenue Glenwood Springs, CO 81601 Phone: (970) 384-3209 Prepared by: Reviewed by: ________________________________________ ____________________________ Name Name Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 4 of 20 ENGINEER’S STATEMENT I hereby attest that this report and plan for the preliminary drainage design for the Alpine Bank Subdivision 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. Michael Alan Shaw, PE # 53656 Date For and on behalf of Galloway & Company, Inc. DEVELOPER’S CERTIFICATION “Alpine Bank hereby certifies that the drainage facilities for The Alpine Bank Subdivision shall be constructed according to the design presented in this report. I understand that the City of Fort Collins does not and will not assume liability for the drainage facilities designed and/or certified by my engineer and that the City of Fort Collins review))s drainage plans pursuant to the Municipal Code; but cannot, on behalf of The Alpine Bank Subdivision, guarantee that final drainage design review will absolve Alpine Bank and/or their successors and/or assigns of future liability for improper design.” Authorized Signature Date Alpine Bank Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 5 of 20 I. General Location and Existing Information ............................................................................................ 6 Location ...................................................................................................................................... 6 Description of Property ................................................................................................................ 6 II. Master Drainage Basin Description ...................................................................................................... 7 Major Basin Description .............................................................................................................. 7 Sub- Basin Description ................................................................................................................ 7 III. Floodplain Information ........................................................................................................................ 8 IV. Project Description ............................................................................................................................. 8 V. Drainage Design Criteria ..................................................................................................................... 8 Regulations ................................................................................................................................. 8 The Four Step Process (Low Impact Development) ..................................................................... 8 Development Criteria Reference and Constraints ........................................................................ 9 Hydrologic Criteria .................................................................................................................... 10 Hydraulic Criteria ...................................................................................................................... 10 VI. Proposed Drainage Facilities ............................................................................................................ 11 General Concept ....................................................................................................................... 11 Specific Details ......................................................................................................................... 11 VII. Variance Requests .......................................................................................................................... 13 VIII. Erosion Control .............................................................................................................................. 13 Construction Material & Equipment ........................................................................................... 14 Maintenance ............................................................................................................................. 14 IX. Conclusions ..................................................................................................................................... 14 Compliance with Standards ....................................................................................................... 14 Variances .................................................................................................................................. 14 Drainage Concept ..................................................................................................................... 14 VI. References....................................................................................................................................... 15 VII. Appendices ..................................................................................................................................... 16 A. Exhibits & Figures ........................................................................................................... 16 B. Hydrologic Computations ................................................................................................ 16 C. Hydraulic Computations .................................................................................................. 16 D. Drainage Maps ............................................................................................................... 16 TABLE OF CONTENTS Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 6 of 20 I. General Location and Existing Information Location The Alpine Bank Subdivision (hereafter referred to as “the site” or “project site”) will be located at the southwest corner of South College Avenue and East Prospect Road. It is bounded on north by an East Prospect Road; on the east by an alley shared with the neighboring residences; on the south by an existing commercial site; and on the west by South College Avenue. Spring Creek is located north of the site. More specifically, the site is located in the Northwest Quarter of Section 24, Township 7 North, Range 69 West of the 6th Principal Meridian, in the City of Fort Collins, County of Larimer and State of Colorado. Refer to Appendix A for a Vicinity Map. Description of Property The project site is approximately 9.0 acres (after replatting with additional right of way dedicated to the City of Fort Collins for the proposed lane widening), and consists of two existing commercial buildings that will be removed, an existing historic home (currently designated for commercial use) that will be relocated within the site to preserve it, and associated parking, drive aisles, and landscaping. Existing grades on the site range from approximately one to eight percent, with historic runoff generally draining across the site and to the existing inlet in the alley along the east side of the site. There are no major drainage ways passing through the project site. According to the USDA NRCS Web Soil Survey, ‘Fort Collins loam, 0 to 3 percent slopes’ covers the entire project site. This soil is associated with Hydrologic Soil Group (HSG) ‘C’. HSG ‘C’ soils have a slow infiltration rate when thoroughly wet and 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. Refer to Appendix A for additional soils information. During the water quality storm event, surface runoff will be collected into an underground storm drain system through a series of roof drain downspouts and inlets throughout the site through which it will be conveyed to an underground water quality facility located at the southeast corner of the site. During the minor (i.e., 2-year) and major (i.e., 100-year) storm events, runoff volume in excess of the water quality event will be released into the existing 30” storm drain main in the alley at or below the current 100-year developed flow rate for the site. Since the proposed development provides a net reduction in impervious area, the proposed outflow rate will be less than the existing site. Also, per ongoing coordination with the City of Fort Collins it is understood that local flooding in the adjacent intersection enters the site in the 100-year storm event and that approximately 19 cfs of runoff enters the site via the existing South College Avenue entry and is directed to the existing inlet in the alley. This value shall be confirmed with additional information to be provided by the City after this initial submittal. This runoff contributes to a pre-existing flooding issue in this alley due to the existing storm drain infrastructure being undersized. This project will not be required to provide detention or to resolve these flooding issues, but will help improve this condition by reducing net impervious area across the site, providing water quality capture volume storage, and by redirecting a significant amount of runoff away from the existing inlet (which flows into a 12” storm drain pipe) and shifting the project outfall just south of this where the existing storm drain increases to a 30” pipe. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 7 of 20 II. Master Drainage Basin Description Major Basin Description The project site is located in the Spring Creek drainage basin. According to the City of Fort Collins website (http://www.fcgov.com/utilities/what-we-do/stormwater/drainage-basins/spring-creek-basin), this basin “is a major watercourse that flows from Spring Canyon Dam at Horsetooth Reservoir to its confluence with the Poudre River. The basin is dominated by residential development, but also includes open space, parks, and isolated areas of commercial and industrial development.” On-site detention storage is not required for the site because it is a redevelopment of an existing site that does not have detention storage and will be reducing the overall impervious area of the site. Water quality for the site has been provided in accordance with the City of Fort Collins LID requirements for the redeveloped portions of the site. An underground water quality facility has been sized for the redeveloped portions of the site in the form of an underground extended detention basin, herein referred to as UG A. Preliminary calculations for the underground basin have been provided in Appendix C. Due to grading constraints and the existing alley being incorporated into the project site, only about 75% of the onsite runoff can be captured and treated by the underground water quality facility, which is similar to the existing condition The current site does not have any LID features so this is a significant improvement from the existing condition. Also, the water quality volume has been sized for the entire site as if were all being captured and treated by the under water quality facility. Sub- Basin Description The site historically drains south and east towards the adjacent alley. Also, portions of the north side of the site drain into East Prospect Road and the sidewalk and tree lawn along the western frontage currently drains into South College Avenue. An existing combination inlet on the north side of the site also captures a small amount of runoff and ties into the existing East Prospect Road combination inlet directly north of the site. Runoff conveyed to South College Avenue is captured by the existing curb inlet in the curbline directly west of the project. This inlet will be impacted by the project and relocated directly west to provide a right turn lane with the development. This inlet will function in the same manner in the new location and existing flow patterns have been maintained. In order to redirect water out of the alley and into the project site, existing drainage patterns were modified wherever feasible to maximize onsite runoff capture. However, several locations could not be modified, such as the following. First, the existing tree lawn on the north side of the site has been preserved at the request of Fort Collins and directs this onsite runoff into East Prospect Avenue. Second, the new proposed sidewalk along South College Avenue associated with the lane widening is part of the project site area but must be directed into the public right-of-way per Larimer County Standards. This is consistent with the existing drainage pattern. The east side of the site has been graded to attempt to direct additional runoff back into the site and away from the alley, however the steep slopes on this site have made some areas infeasible to capture runoff onsite. Wherever it is infeasible to capture this runoff, the existing drainage pattern is being maintained and overall, the runoff entering the alley is significantly reduced. In the 2-year event the runoff entering the alley inlet has been reduced from approximately 2.0 cfs to 0.3 cfs and in the 100-year event this has been reduced from approximately 8.2 cfs to 1.1 cfs (not including the flood bypass from College). There are a few proposed storm inlets within the site which collect runoff and direct it to the underground water quality facility at the southeast corner of the site before it is released into the Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 8 of 20 existing storm drain infrastructure in the alley and ultimately drains to Spring Creek. This outfall is consistent with the existing drainage pattern for the site. At the sub-basin level, no offsite runoff is anticipated to enter the site, with the exception of 19 cfs of local flooding from South College Avenue that currently enters the site and sheet flows into the alley inlet. A description of each basin and their characteristics can be found later in the report. There are no known irrigation, reservoir, or other facilities that influence, or are influenced by, the local drainage. III. Floodplain Information The project site is shown on FEMA Map Number 08069C0979H (refer to Appendix A for FEMA Firmette). This map shows that the project is not impacted by an existing floodplain/floodway. Refer to Appendix A for a copy of the Firmette. IV. Project Description The Alpine Bank Subdivision will be developed in one phase and is approximately 9.0 acres. The two existing commercial buildings will be removed, and the existing historic home (currently designated for commercial use) will be relocated to the south side of the site to preserve it. The existing parking lot and drive aisles will be removed and a proposed bank building will be built in the northwest corner of the lot V. Drainage Design Criteria Regulations This preliminary drainage design presented herein is prepared in accordance with the Fort Collins Stormwater Criteria Manual, November 2017 (FCSCM), the Mile High Flood District (MHFD) Urban Storm Drainage Criteria Manual, January 2016 (USDCM), and Chapter 10, Flood Prevention and Protection, of the Fort Collins City Code. No other drainage reports could be provided for the site by the City of Fort Collins. The Four Step Process (Low Impact Development) At this preliminary stage of the design process, we developed a commensurate implementation of the ‘The Four-Step Process’ for stormwater quality management. Ordinance No. 007, 2016 requires that no less than seventy-five percent (75%) of any newly developed or redeveloped area be treated using one or a combination of LID techniques. As previously mentioned, the runoff for the modified areas collected onsite will be treated using and underground LID water quality system. This LID system will address 100% of the captured volume rather than using a combination of LID and standard methods. Consistent with the ordinance referenced above, 75% of the new or modified impervious area is captured and treated by the underground water quality facility. And it has also been sized assuming a 100% capture rate to provide additional water quality storage volume for larger storm events. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 9 of 20 Step 1 - Employ runoff reduction practices The attached drainage map (see Appendix D) delineates the proposed drainage basins, each of which drains to the proposed underground water quality system, UG A wherever feasible. Underground systems are an accepted LID method when surface BMPs are infeasible, which consist of an underground chamber that provide stormwater quality treatment via sedimentation, screening, filtration, and other physical and chemical processes. Step 2 - Implement BMPs that provide a Water Quality Capture Volume (WQCV) Due to site constraints, an underground storage system will provide the necessary Water Quality Capture Volume (WQCV). This has been sized for the entire project area, although only 75% of the project impervious area is directed to the facility due to reasons described earlier in the report. Step 3 - Stabilize drainageways The developed runoff generated by the proposed redevelopment will drain to an existing storm drain system located within the existing alley directly east of the project site. This system drains north and outfalls into Spring Creek. Our work assumes that an appropriate level of stabilization exists at the outfall into Spring Creek. Step 4 - Implement site specific and other source control BMPs Site specific considerations such as material handling/storage and other site operations will be addressed in the Stormwater Management Plan (SWMP). Development Criteria Reference and Constraints This preliminary drainage design presented herein is prepared in accordance with the Fort Collins Stormwater Criteria Manual, November 2017 (FCSCM) and the Mile High Flood District (MHFD) Urban Storm Drainage Criteria Manual, January 2016 (USDCM). No other drainage reports could be provided for the site by the City of Fort Collins. Existing runoff for the proposed site generally drains to the south and east across the site. The majority of the on-site runoff is captured by an existing storm sewer inlet in the adjacent alley which directs runoff south via a 12” storm pipe, which increases to a 30” pipe at the next manhole in the alignment. Capacity calculations for the proposed and existing portions of the storm sewer system will be provided with a subsequent submittal once an updated drainage study for this area has been provided by the City. This is anticipated to be received and reviewed shortly after this submittal. However, at this time it is known by the City that there are existing flooding issues in this alley due to the existing infrastructure being undersized and due to localized flooding in South College Avenue, as described earlier in the report. Therefore, it is known that the existing system does not have capacity, however, the proposed project will be matching or improving the existing conditions and release rates thereby improving the system overall. Also, the City noted that a future Capital Improvement Project is planned for this alley to upsize the existing infrastructure and mitigate these pre-existing flooding issues. Per conversations with the City, a timeframe is not known yet for this project at this time. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 10 of 20 Hydrologic Criteria For urban catchments that are not complex and are generally 160 acres or less in size, it is acceptable that the design storm runoff be analyzed using the Rational Method. The Rational Method is often used when only the peak flow rate or total volume of runoff is needed (e.g., storm sewer sizing or simple detention basin sizing). The Rational Method was used to estimate the peak flow at each design point. Routing calculations (i.e., time attenuation) that aggregate the basins draining to a specific design point are include in the Rational Method calculations in Appendix B. The Rational Method is based on the Rational Formula: Q = CiA Where: Q = the maximum rate of runoff, cfs C = a runoff coefficient that is the ratio between the runoff volume from an area and the average rate of rainfall depth over a given duration for that area i = average intensity of rainfall in inches per hour for a duration equal to the Time of Concentration (Tc) A = area, acres Runoff Coefficients were determined based on Tables 3.2-1, 3.2-2, and 3.2-3 of the the FCSCM. The one-hour rainfall Intensity-Duration-Frequency tables for use with the Rational Method of runoff analysis are provided in Table 3.4-1 of the FCSCM. The 2-year and 100-year storm events serve as the basis for the drainage system design. The 2-year storm is considered the minor storm event. It has a fifty percent probability of exceedance during any given year. The 100-year storm is considered the major storm event. It has a one percent probability of exceedance during any given year. The 2-year drainage system, at a minimum, must be designed to transport runoff from the 2-year recurrence interval storm event with minimal disruption to the urban environment. The 100-year drainage system, as a minimum, must be designed to convey runoff from the 100-year recurrence interval flood to minimize life hazards and health, damage to structures, and interruption to traffic and services. Hydraulic Criteria There are three on-site basins which drain to the proposed storm sewer system, which are identified in the proposed drainage map (Appendix D) as Basins A, B, and C. Runoff from each basin will be collected by storm sewer inlets and pipes and conveyed onsite to the proposed underground water quality facility before entering the existing storm drain system in the adjacent alley. Basin A is collected by a storm sewer system at the northeast corner of the site. Basin B is collected by a storm drain inlet in the bank drive through area, and Basin C is collected by an inlet at the southeast corner of the site adjacent to the alley. Additional areas for the site not collected by the proposed storm drain system are designated as Off-Site Basins (OS) and will drain offsite to existing storm drain infrastructure, consistent with the existing drainage pattern. Runoff from these offsite basins will be released untreated and undetained toward existing inlets in East Prospect Road and South College Avenue as described in more detail earlier in this report. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 11 of 20 Inlet Capacity Analysis Inlet calculations are not required to be included with this preliminary report and will provided with the Final Drainage Report. Storm Drain Capacity Analysis The preliminary storm drain system is typically sized to convey the sum of the 100-year developed runoff at each design point draining into the system. The pipes are sized to convey this runoff without surcharging (full-flow capacity). This method should provide a conservative estimate of total runoff and pipe sizes. Although the existing storm drain system in the alley is undersized, it is currently used at the outfall for the existing development and will be able to continue to serve as the outfall for the proposed development. The proposed development is not required to provide detention to reduce the site release rate, however it will ultimately be reducing the impact on this system by lowering the release rate and reducing the overall impervious area of the site. Preliminary pipe sizing calculations will be provided with a subsequent submittal and included in Appendix C at that time. VI. Proposed Drainage Facilities General Concept This final design presents the detailed design of the proposed system for collecting and conveying developed runoff from current and proposed development at the Alpine Bank Subdivision site to the Stormwater quality and detention features and offsite systems. The existing site runoff drains to existing storm sewer inlets within the alley and adjacent streets as described in more detail earlier on in this report. The proposed design generally matches this existing drainage pattern and includes the implementation of and underground StormTech system to provide water quality and detention for the site. Drainage patterns have only been modified to maximize the amount of runoff directed to the water quality treatment facility. Specific Details The site has been broken into three basins, each with their own set of sub-basins. A description of each basin and their characteristics can be found below. The intent of the drainage design is to have the runoff from the majority of the site collected and drain through a water quality facility prior to entering the existing storm sewer system offsite. UG A has been sized based on the City of Fort Collins LID requirements for the necessary portions of the site, which will be located at the downstream connection point to the existing storm drain system at the southeast corner of the site. The released stormwater from the site will travel in the existing storm sewer system in the adjacent alley, and ultimately reach Spring Creek. Basin A Basin A consists of the north side of the site and is comprised of 4 sub-basins. The basin includes a portion of the bank roof (connected via downspouts), the landscape area at the northeast corner of the site, and a portion of the large raised planter wrapped around the building on the north side and a portion of the west side. Runoff from Basin A will be collected by the proposed storm sewer system and conveyed to the southeast corner of the site to the proposed underground water quality facility, and ultimately discharge into the existing storm sewer system in College Ave. Basin B Basin B consists of the drive through banking area east of the bank building and is comprised of 7 sub-basins. The basin includes the drive through banking areas, additional portions of the bank roof, Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 12 of 20 and a portion of the bank entry area. Runoff from Basin B will be collected by the proposed storm sewer system and conveyed south to the southeast corner of the site to the proposed underground water quality facility, and ultimately discharge into the existing storm sewer system in College Ave. Basin C Basin C consists of the southern portion of the site and is comprised of 3 sub-basins. The basin includes the main drive aisle, parking, the historic building, and portions of the bank roof. Runoff from Basin C will be collected by the proposed storm sewer system and conveyed south to the southeast corner of the site to the proposed underground water quality facility, and ultimately discharge into the existing storm sewer system in College Ave. Offsite Basins The remainder of the site consists of basins that flow offsite, as is current with the existing drainage pattern. These basins are located along East Prospect Road (OS-1), South College Avenue (OS-2) and the existing alley to the east (OS-3). These basins include sidewalk, tree lawn, and landscape areas between the sidewalk and proposed bank building. They also include portions of the alley that are located on the project site where the existing drainage pattern cannot be modified to redirect additional runoff into the site. The characteristics of the tributary areas draining to these inlets will remain virtually the same, so anticipated flow rates generated should be the same and not negatively impact the existing storm sewer system. Once in the existing storm sewer inlets, the stormwater from this basin is conveyed through the existing storm sewer system and ultimately reaches Spring Creek. Basin OS-E1 has also been delineated to estimate the area in College contributing to the existing inlet in College. However, additional information is needed from the City to confirm the existing runoff in this basin to provide inlet calculations for the College inlet with the Final Drainage Report. Water Quality Enhancement The site has been divided into multiple drainage basins as described above. Runoff from each basin will be collected and conveyed to UG A, which provides water quality treatment in the form of an underground LID system. The LID Summary Table below identifies the on-site impervious areas of the proposed improvements. In the proposed condition, there is approximately 0.70 acres of on-site new or modified impervious area. Of that area, 0.17 acres of impervious area are infeasible to be captured by the on-site drainage system due to grading constraints where the proposed improvements match existing grades. Thus, the system can capture 0.53 acres of the total on-site new and modified impervious area (76%). In lieu of the uncaptured area, the underground water quality facility has been sized for 100% of the project site area. Based on coordination with the City, a reduced capture volume is acceptable for this site due to significant grading constraints and existing drainage patterns that cannot be modified. Also, a significant portion of the impervious area that cannot be captured consists of public sidewalk that drains into College (0.08 acres). When this portion of the impervious area is removed from the calculation this reduces the on-site new or modified impervious area to 0.62 acres (since the sidewalk is not technically “on-site” despite being within the property lines. In this case, the actual capture rate is 85%. These impervious areas are summarized in the table below. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 13 of 20 LID – Impervious Area Summary Table Proposed Impervious Area (ac) (ac) On-Site New and Modified Impervious Area 0.70 100% Impervious Area Infeasible to Capture 0.17 24% Total Impervious Area Captured 0.53 76% Public Sidewalk Impervious Area (Onsite) 0.08 11% Actual On-Site New and Modified Impervious Area 0.62 100% Actual Total Impervious Area Captured 0.53 85% In conformance with the requirement identified under the Four Step Process to treat at least 75% of impervious areas through LID methods, 100% of the captured on-site proposed impervious areas will be treated through the proposed underground water quality system. A delineation of the on-site area boundaries for the existing and proposed conditions can be found in the Impervious Area Exhibit in Appendix D. More information for the calculation and sizing of the water quality system is provide in Appendix B. Water Quality treatment will be provided in the isolator rows of the StormTech detention system. The total volume of water quality has been calculated based on a release rate of 0.35 gpm/sf of storage area. Structures within the StormTech system will divert flows in excess of the water quality event to bypass the system and leave the site at the system outfall point. A summary of the water quality system calculations can be found in Appendix B. Storm Water Detention The City has confirmed that Storm Water Detention will not be required for this project. VII. Variance Requests No variances are being requested with the proposed improvements described herein. VIII. Erosion Control A General Permit for Stormwater Discharge Associated with Construction Activities issued by the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division (WQCD), will be acquired for the site. A Stormwater Management Plan (SWMP) should be prepared to identity the Best Management Practices (BMPs) which, when implemented, will meet the requirements of said General Permit. Below is a summary of SWMP requirements which may be implemented on-site. The following temporary BMPs may be installed and maintained to control on-site erosion and prevent sediment from traveling off-site during construction: • Silt Fence – a woven synthetic fabric that filters runoff. The silt fence is a temporary barrier that is placed at the base of a disturbed area. • Vehicle Tracking Control – a stabilized stone pad located at points of ingress and egress on a construction site. The stone pad is designed to reduce the amount of mud transported onto public roads by construction traffic. • Straw Wattles – wattles act as a sediment filter. They are a temporary BMP and require proper installation and maintenance to ensure their performance. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 14 of 20 • Inlet protection – Inlet protection will be used on all existing and proposed storm inlets to help prevent debris from entering the storm sewer system. Inlet protection generally consists of straw wattles or block and gravel filters. Compliance with Erosion Control Criteria and all Erosion Control Materials in greater detail will be provided with the Final Drainage Report Construction Material & Equipment The contractor shall store all construction materials and equipment and shall provide maintenance and fueling of equipment in confined areas on-site from which runoff will be contained and filtered. Maintenance The temporary BMPs will be inspected by the contractor at a minimum of once every two weeks and after each significant storm event. The property owner will be responsible for routine and non-routine maintenance of the temporary BMPs. Routine maintenance includes: • Remove sediment from the bottom of the temporary sediment basin when accumulated sediment occupies about 20% of the design volume or when sediment accumulation results in poor drainage. • Debris and litter removal-remove debris and litter to minimize outlet clogging and improve aesthetics as necessary. • Inspection of the facility-inspect the facility annually to ensure that it functions as initially intended. • Cleaning and repair of BMP’s is required when sediment has built up or the BMP is not working properly. IX. Conclusions Compliance with Standards The design presented in this final drainage report for the Alpine Bank Subdivision has been prepared in accordance with the design standards and guidelines presented in the Fort Collins Stormwater Criteria Manual and the MHFD Urban Storm Drainage Criteria Manual. Variances No variances are being requested with the proposed improvements described herein. Drainage Concept The proposed Alpine Bank Subdivision storm drainage improvements should provide adequate collection and Water Quality protection for the developed site. The proposed drainage design will sufficiently drain the proposed development and should not negatively impact the existing condition of the overall storm drainage system. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 15 of 20 VI. References 1. Fort Collins Stormwater Criteria Manual, November 2017 2. Urban Storm Drainage Criteria Manual, Mile High Flood District, January 2016 (with current revisions). 3. Flood Insurance Rate Map – Larimer County, Colorado and Incorporated Areas Community Panel No. 08069C0979H, Effective May 2, 2012. 4. Soil Map – Larimer County Area, Colorado as available through the Natural Resources Conservation Service National Cooperative Soil Survey web site via Web Soil Survey 2.0. Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. Page 16 of 20 VII. Appendices A. Exhibits & Figures • Vicinity Map • USGS Soil Survey Data • FEMA Flood Insurance Rate Map B. Hydrologic Computations • Existing Condition Basin Summary • Existing Condition Rational Method Computations • Existing Minor and Major Storm Runoff Computations • Proposed Condition Basin Summary • Proposed Condition Rational Method Computations • Proposed Minor and Major Storm Runoff Computations • Modified FAA Calculations - Water Quality • Modified FAA Calculations – 100-Year Routing • Water Quality System Calculation Summary C. Hydraulic Computations • ADS StormTech Specifications • ADS StormTech Stage Storage Summary D. Drainage Maps • Impervious Area Exhibit • Existing Drainage Map • Proposed Drainage Map • Existing Onsite & Offsite Flows (Provided by City of Fort Collins, Annotation Added) Alpine Bank Subdivision 12/2/2020 Galloway & Company, Inc. APPENDIX A Exhibits and Figures USGS The National Map: Orthoimagery. Data refreshed October, 2020. National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 11/2/2020 at 3:07 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 105°4'56"W 40°34'15"N 105°4'19"W 40°33'48"N United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, ColoradoNatural Resources Conservation Service November 12, 2020 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map (Alpine Bank Project).............................................................................9 Legend................................................................................................................10 Map Unit Legend (Alpine Bank Project)..............................................................11 Map Unit Descriptions (Alpine Bank Project)......................................................11 Larimer County Area, Colorado......................................................................13 35—Fort Collins loam, 0 to 3 percent slopes..............................................13 References............................................................................................................15 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map (Alpine Bank Project)44906004490610449062044906304490640449065044906604490670449068044906904490600449061044906204490630449064044906504490660449067044906804490690493490 493500 493510 493520 493530 493540 493550 493560 493490 493500 493510 493520 493530 493540 493550 493560 40° 34' 1'' N 105° 4' 36'' W40° 34' 1'' N105° 4' 33'' W40° 33' 57'' N 105° 4' 36'' W40° 33' 57'' N 105° 4' 33'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 20 40 80 120 Feet 0 5 10 20 30 Meters Map Scale: 1:502 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. 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 15, Jun 9, 2020 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. Custom Soil Resource Report 10 Map Unit Legend (Alpine Bank Project) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 35 Fort Collins loam, 0 to 3 percent slopes 1.1 100.0% Totals for Area of Interest 1.1 100.0% Map Unit Descriptions (Alpine Bank Project) The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, Custom Soil Resource Report 11 onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Larimer County Area, Colorado 35—Fort Collins loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlnc Elevation: 4,020 to 6,730 feet Mean annual precipitation: 14 to 16 inches Mean annual air temperature: 46 to 48 degrees F Frost-free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Fort collins and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Fort Collins Setting Landform:Stream terraces, interfluves Landform position (three-dimensional):Interfluve, tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Pleistocene or older alluvium and/or eolian deposits Typical profile Ap - 0 to 4 inches: loam Bt1 - 4 to 9 inches: clay loam Bt2 - 9 to 16 inches: clay loam Bk1 - 16 to 29 inches: loam Bk2 - 29 to 80 inches: loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.20 to 2.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:12 percent Maximum salinity:Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Available water capacity:High (about 9.1 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Nunn Percent of map unit:10 percent Landform:Stream terraces Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY002CO - Loamy Plains Hydric soil rating: No Vona Percent of map unit:5 percent Landform:Interfluves Landform position (three-dimensional):Side slope, interfluve Down-slope shape:Linear Across-slope shape:Linear Ecological site:R067BY024CO - Sandy Plains Hydric soil rating: No Custom Soil Resource Report 14 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 15 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 16 Alpine Bank Subdivision 12/2/2020 APPENDIX B Hydrologic Computations Tributary Area tc | 2-Year tc | 100-Year Q2 Q100 Sub-basin (acres)(min)(min)(cfs)(cfs) EX-1 0.04 0.95 1.00 5.0 5.0 0.1 0.4 E2-OS 0.05 0.45 0.56 5.0 5.0 0.1 0.3 EX-3 0.09 0.91 1.00 5.0 5.0 0.2 0.9 EX-4 0.10 0.95 1.00 5.0 5.0 0.3 1.0 EX-5 0.40 0.71 0.89 5.3 5.0 0.8 3.6 EX-6 0.03 0.95 1.00 5.0 5.0 0.1 0.3 EX-7 0.02 0.85 1.00 5.0 5.0 0.1 0.2 EX-8 0.04 0.95 1.00 5.0 5.0 0.1 0.4 EX-9 0.08 0.95 1.00 5.0 5.0 0.2 0.8 EX-10 0.01 0.95 1.00 5.0 5.0 0.0 0.1 EX-11 0.03 0.95 1.00 5.0 5.0 0.1 0.3 OS-E1 0.61 0.90 1.00 5.0 5.0 1.5 6.0 OS-E2 0.02 0.95 1.00 5.0 5.0 0.0 0.2 Onsite Total 0.90 0.81 ---2.1 8.3 Offsite Total 0.62 0.90 ---1.6 6.2 Total Tributary to Site -----2.0 8.2 Onsite Total + Flood Flow Bypass -----2.0 27.2 BASIN SUMMARY TABLE - EXISTING C2 C100 H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Existing.xlsPage 1 of 6 12/1/2020 Subdivision:Alpine Bank Subdivision Project Name:Alpine Bank Location:CO, Fort Collins Project No.: Calculated By:M. Shaw Checked By:P. Dalrymple Date:12/2/20 Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family 95%5%62.5%70%75%80% EX-1 0.04 95 0.04 95 20 0.00 0 95 0.00 0 0.95 E2-OS 0.05 95 0.02 31 20 0.04 13 95 0.00 0 0.45 EX-3 0.09 95 0.08 89 20 0.01 1 95 0.00 0 0.91 EX-4 0.10 95 0.00 0 20 0.00 0 95 0.10 95 0.95 EX-5 0.40 95 0.27 64 20 0.13 6 95 0.00 0 0.71 EX-6 0.03 95 0.00 0 20 0.00 0 95 0.03 95 0.95 EX-7 0.02 95 0.02 82 20 0.00 3 95 0.00 0 0.85 EX-8 0.04 95 0.04 95 20 0.00 0 95 0.00 0 0.95 EX-9 0.08 95 0.00 0 20 0.00 0 95 0.08 95 0.95 EX-10 0.01 95 0.01 95 20 0.00 0 95 0.00 0 0.95 EX-11 0.03 95 0.03 95 20 0.00 0 95 0.00 0 0.95 OS-E1 0.61 95 0.56 88 20 0.04 1 95 0.00 0 0.90 OS-E2 0.02 95 0.02 95 20 0.00 0 95 0.00 0 0.95 Onsite Total 0.90 0.81 Offsite Total 0.62 0.90 Total 1.53 0.84 Area Weighted C2Basin ID Total Area (ac)Runoff Coefficient Area (ac) Building Roof Runoff Coefficient COMPOSITE RUNOFF COEFFICIENTS - EXISTING Area (ac)Area Weighted Asphalt + Concrete Walks Lawns, Heavy Soil: Flat <2% Area Weighted Runoff Coefficient Area (ac) ALB000001.20 Page 2 Drainage Calculations Subdivision:Alpine Bank Subdivision Project Name:Alpine Bank Location:CO, Fort Collins Project No.: Calculated By:M. Shaw Checked By:P. Dalrymple Date:12/2/20 Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family 95%5%62.5%70%75%80% EX-1 0.04 100 0.04 100 2 0.00 0 90 0.00 0 100% E2-OS 0.05 100 0.02 33 2 0.04 1 90 0.00 0 34% EX-3 0.09 100 0.08 94 2 0.01 0 90 0.00 0 94% EX-4 0.10 100 0.00 0 2 0.00 0 90 0.10 90 90% EX-5 0.40 100 0.27 68 2 0.13 1 90 0.00 0 68% EX-6 0.03 100 0.00 0 2 0.00 0 90 0.03 90 90% EX-7 0.02 100 0.02 86 2 0.00 0 90 0.00 0 87% EX-8 0.04 100 0.04 100 2 0.00 0 90 0.00 0 100% EX-9 0.08 100 0.00 0 2 0.00 0 90 0.08 90 90% EX-10 0.01 100 0.01 100 2 0.00 0 90 0.00 0 100% EX-11 0.03 100 0.03 100 2 0.00 0 90 0.00 0 100% OS-E1 0.61 100 0.56 93 2 0.04 0 90 0.00 0 93% OS-E2 0.02 100 0.02 100 2 0.00 0 90 0.00 0 100% Onsite Total 0.90 79% Offsite Total 0.62 93% Total 1.53 85% Area WeightedArea Weighted % Imp Area (ac)Area Weighted % Imp Area (ac) COMPOSITE % IMPERVIOUSNESS - EXISTING ALB000001.20 Asphalt + Concrete Walks Lawns, Heavy Soil: Flat <2%Building Roof % ImpBasin ID Total Area (ac)% Imp Area (ac) Page 3 Drainage Calculations Subdivision:Alpine Bank Subdivision Project Name:Alpine Bank Location:CO, Fort Collins Project No.: Calculated By:M. Shaw Checked By:P. Dalrymple Date:12/2/20 1 BASIN D.A.Hydrologic C2 C5 C100 L S Ti | 2-Year Ti | 100-Year L S R VEL.Tt COMP. Tc | 2-Year COMP. Tc | 100-Year TOTAL Urbanized Tc Tc | 2-Year Tc | 100-Year ID (AC)Soils Group Cf=1.00 Cf=1.00 Cf=1.25 (FT)(%)(MIN)(MIN)(FT)(%)(FT)(FPS)(MIN)(MIN)(MIN)LENGTH(FT)(MIN)(MIN)(MIN) EX-1 0.04 C 0.95 0.95 1.00 45 3.80 1.2 0.8 25 0.50 0.1 1.6 0.3 1.5 1.1 70 10.4 5.0 5.0 E2-OS 0.05 C 0.45 0.45 0.56 12 5.00 2.5 2.0 0 1.00 0.1 2.3 0.0 2.5 2.0 12 10.1 5.0 5.0 EX-3 0.09 C 0.91 0.91 1.00 80 8.00 1.6 0.8 0 1.00 0.1 2.3 0.0 1.6 0.8 80 10.4 5.0 5.0 EX-4 0.10 C 0.95 0.95 1.00 35 1.00 1.7 1.1 0 1.00 0.1 2.3 0.0 1.7 1.1 35 10.2 5.0 5.0 EX-5 0.40 C 0.71 0.71 0.89 155 5.00 5.3 2.9 0 1.00 0.1 2.3 0.0 5.3 2.9 155 10.9 5.3 5.0 EX-6 0.03 C 0.95 0.95 1.00 20 20.00 0.5 0.3 0 1.00 0.1 2.3 0.0 0.5 0.3 20 10.1 5.0 5.0 EX-7 0.02 C 0.85 0.85 1.00 25 4.50 1.4 0.6 0 1.00 0.1 2.3 0.0 1.4 0.6 25 10.1 5.0 5.0 EX-8 0.04 C 0.95 0.95 1.00 30 2.50 1.1 0.8 0 1.00 0.1 2.3 0.0 1.1 0.8 30 10.2 5.0 5.0 EX-9 0.08 C 0.95 0.95 1.00 35 2.00 1.3 0.9 0 1.00 0.1 2.3 0.0 1.3 0.9 35 10.2 5.0 5.0 EX-10 0.01 C 0.95 0.95 1.00 50 2.00 1.6 1.0 0 1.00 0.1 2.3 0.0 1.6 1.0 50 10.3 5.0 5.0 EX-11 0.03 C 0.95 0.95 1.00 15 16.00 0.4 0.3 0 1.00 0.1 2.3 0.0 0.4 0.3 15 10.1 5.0 5.0 OS-E1 0.61 C 0.90 0.90 1.00 90 2.20 2.8 1.4 60 0.50 0.1 1.6 0.6 3.4 2.0 150 10.8 5.0 5.0 OS-E2 0.02 C 0.95 0.95 1.00 15 1.00 1.1 0.7 0 1.00 0.1 2.3 0.0 1.1 0.7 15 10.1 5.0 5.0 NOTES: Ti = (1.87*(1.1 - CCf)*(L)^0.5)/((S)^0.33), S in % Tt=L/60V (Velocity From Fig. 501) Velocity V=(1.4/n)*(R^(2/3))*(S^0.5), S in ft/ft, R=Area/Wetted Perimeter in ft, n=Roughness Coeff., Tc Check = 10+L/180 For Urbanized basins a minimum Tc of 5.0 minutes is required. For non-urbanized basins a minimum Tc of 10.0 minutes is required DATA Tc CHECK ALB000001.20 TRAVEL TIMESUB-BASIN (Ti) STANDARD FORM SF-2 TIME OF CONCENTRATION - EXISTING (URBANIZED BASINS)(Tt)FINALINITIAL/OVERLAND Page 4 Drainage Calculations Project Name:Alpine Bank Subdivision:Alpine Bank Subdivision Project No.:ALB000001.20 Location:CO, Fort Collins Calculated By:M. Shaw Design Storm:Checked By:P. Dalrymple Date: TRAVEL TIME STREET DesignPointBasinIDArea(Ac)RunoffCoeff.|C2Tc|2-Year(min)C*A(Ac)I(in/hr)Q(cfs)Tc(min)C*A(Ac)I(in/hr)Q(cfs)Slope(%)StreetFlow(cfs)DesignFlow(cfs)Slope(%)PipeSize(inches)Length(ft)Velocity(fps)Tt(min)REMARKS EX-1 0.04 0.95 5.0 0.04 2.85 0.1 E2-OS 0.05 0.45 5.0 0.02 2.85 0.1 This basin flows offsite and is tributary to the inlet in Prospect. EX-3 0.09 0.91 5.0 0.08 2.85 0.2 EX-4 0.10 0.95 5.0 0.09 2.85 0.3 EX-5 0.40 0.71 5.3 0.29 2.79 0.8 EX-6 0.03 0.95 5.0 0.03 2.85 0.1 EX-7 0.02 0.85 5.0 0.02 2.85 0.1 EX-8 0.04 0.95 5.0 0.04 2.85 0.1 EX-9 0.08 0.95 5.0 0.08 2.85 0.2 EX-10 0.01 0.95 5.0 0.01 2.85 0.0 EX-11 0.03 0.95 5.0 0.03 2.85 0.1 OS-E1 0.61 0.90 5.0 0.54 2.85 1.5 This basin is tributary to the inlet in College Avenue - assumed no flows enter site in 2-year storm event. OS-E2 0.02 0.95 5.0 0.02 2.85 0.0 This basin is outside the property line but flows into the site. Onsite Total 0.90 2.1 Offsite Total 0.62 1.6 Total Tributary to Site 0.87 2.0 EX-1, EX-3 through EX-11, and OS-E2 Total Tributary to College Inlet 0.61 1.55 OS-E1 - assumed basin area for offsite flows entering College Inlet - assumed to be contained by inlet in 2-yr event and not overtop curb into project site Total Site Contribution to Prospect Inlet 0.05 0.07 E2-OS - does not account for other flows to Prospect, only project flows leaving site College Avenue Flooding Site Bypass -0.0 Assumed no flooding entering site in 2-yr storm event per coordination with City of Fort Collins Onsite Total + Flood Flow Bypass -2.0 This is the same as the 2-yr Onsite Total Flow, shown for reference/comparison to the 100-year event DIRECT RUNOFF TOTAL RUNOFF STREET PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN - EXISTING (RATIONAL METHOD PROCEDURE) 2-Year 12/2/20 Page 5 Drainage Calculations Project Name:Alpine Bank Subdivision:Alpine Bank Subdivision Project No.:ALB000001.20 Location:CO, Fort Collins Calculated By:M. Shaw Design Storm:Checked By:P. Dalrymple Date: TRAVEL TIME STREET DesignPointBasinIDArea(Ac)RunoffCoeff.|C100Tc|100-Year(min)C*A(Ac)I(in/hr)Q(cfs)Tc(min)C*A(Ac)I(in/hr)Q(cfs)Slope(%)StreetFlow(cfs)DesignFlow(cfs)Slope(%)PipeSize(inches)Length(ft)Velocity(fps)Tt(min)REMARKS EX-1 0.04 1.00 5.0 0.04 9.95 0.4 E2-OS 0.05 0.56 5.0 0.03 9.95 0.3 EX-3 0.09 1.00 5.0 0.09 9.95 0.9 EX-4 0.10 1.00 5.0 0.10 9.95 1.0 EX-5 0.40 0.89 5.0 0.36 9.95 3.6 EX-6 0.03 1.00 5.0 0.03 9.95 0.3 EX-7 0.02 1.00 5.0 0.02 9.95 0.2 EX-8 0.04 1.00 5.0 0.04 9.95 0.4 EX-9 0.08 1.00 5.0 0.08 9.95 0.8 EX-10 0.01 1.00 5.0 0.01 9.95 0.1 EX-11 0.03 1.00 5.0 0.03 9.95 0.3 OS-E1 0.61 1.00 5.0 0.61 9.95 6.0 OS-E2 0.02 1.00 5.0 0.02 9.95 0.2 Onsite Total 0.90 8.3 Offsite Total 0.62 6.2 Total Tributary to Site 0.87 8.2 Total Tributary to College Inlet 0.61 6.03 Total Site Contribution to Prospect Inlet 0.05 0.30 College Avenue Flooding Site Bypass -19.0 Assumed 19 cfs enters site after College inlet is flooded and water overtops curb to enter site. Onsite Total + Flood Flow Bypass -27.2 This is the assumed 100-yr flowrate entering the existing inlet in the alley at the southeast corner of the project. Proposed project outflows must be below this rate in the 100-yr storm event. PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN - EXISTING (RATIONAL METHOD PROCEDURE) 100-Year DIRECT RUNOFF TOTAL RUNOFF STREET 12/2/20 Page 6 Drainage Calculations Tributary Area tc | 2-Year tc | 100-Year Q2 Q100 Sub-basin (acres)(min)(min)(cfs)(cfs) A-1 0.01 0.20 0.25 5.0 5.0 0.0 0.0 A-2R 0.01 0.95 1.00 5.0 5.0 0.0 0.0 A-3 0.01 0.20 0.25 5.0 5.0 0.0 0.0 A4-R 0.06 0.95 1.00 5.0 5.0 0.2 0.6 B-1 0.13 0.73 0.91 5.0 5.0 0.3 1.2 B2-R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 B3-R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 B4-R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 B5-R 0.02 0.95 1.00 5.0 5.0 0.1 0.2 B6-R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 B7-R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 C-1 0.35 0.78 0.97 5.0 5.0 0.8 3.4 C-2R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 C-3R 0.01 0.95 1.00 5.0 5.0 0.0 0.1 OS-1 0.04 0.36 0.45 5.0 5.0 0.0 0.2 OS-2 0.08 0.79 0.99 5.0 5.0 0.2 0.8 OS-3 0.11 0.83 1.00 5.0 5.0 0.3 1.1 OS-E1 0.62 0.91 1.00 5.0 5.0 1.6 6.2 Basin A 0.09 0.76 ---0.2 0.7 Basin B 0.21 0.81 ---0.5 2.0 Basin C 0.37 0.79 ---0.8 3.6 WQ Chamber Tributary (A, B & C)0.67 0.79 ---1.5 6.3 Flow Leaving Site (Offsite Basins)0.23 0.74 ---0.5 2.1 Total Project Lot Area 0.90 0.78 ---2.0 8.4 College Avenue Flooding Site Bypass -----0.0 19.0 Onsite Total + Flood Flow Bypass -----1.5 25.3 BASIN SUMMARY TABLE - PROPOSED C2 C100 H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xlsPage 1 of 8 12/1/2020 Subdivision:Alpine Bank Marketplace Project Name:Alpine Bank Location:CO, Fort Collins Project No.: Calculated By:M. Shaw Checked By:P. Dalrymple Date:12/2/20 Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family 95%5%62.5%70%75%80% A-1 0.01 95 0.00 0 20 0.01 20 95 0.00 0 0.20 A-2R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 A-3 0.01 95 0.00 0 20 0.01 20 95 0.00 0 0.20 A4-R 0.06 95 0.00 0 20 0.00 0 95 0.06 95 0.95 B-1 0.13 95 0.09 67 20 0.04 6 95 0.00 0 0.73 B2-R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 B3-R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 B4-R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 B5-R 0.02 95 0.00 0 20 0.00 0 95 0.02 95 0.95 B6-R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 B7-R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 C-1 0.35 95 0.24 66 20 0.08 5 95 0.03 8 0.78 C-2R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 C-3R 0.01 95 0.00 0 20 0.00 0 95 0.01 95 0.95 OS-1 0.04 95 0.01 20 20 0.03 16 95 0.00 0 0.36 OS-2 0.08 95 0.07 75 20 0.02 4 95 0.00 0 0.79 OS-3 0.11 95 0.09 80 20 0.02 3 95 0.00 0 0.83 OS-E1 0.62 95 0.59 90 20 0.03 1 95 0.00 0 0.91 Basin A 0.09 -0.00 --0.02 --0.06 -0.76 Basin B 0.21 -0.09 --0.04 --0.08 -0.81 Basin C 0.37 -0.24 --0.08 --0.05 -0.79 WQ Chamber Tributary (A, B & C)0.67 -0.33 --0.14 --0.20 -0.79 Flow Leaving Site (Offsite Basins)0.23 -0.17 --0.06 --0.00 -0.74 Total Project Lot Area 0.90 -0.50 --0.20 --0.20 -0.78 COMPOSITE RUNOFF COEFFICIENTS - PROPOSED Area (ac)Area Weighted Asphalt + Concrete Walks Lawns, Heavy Soil: Flat <2% Area Weighted Runoff Coefficient Area (ac) ALB000001.20 Area Weighted C2Basin ID Total Area (ac)Runoff Coefficient Area (ac) Building Roof Runoff Coefficient H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 2 of 8 12/1/2020 Subdivision:Alpine Bank Marketplace Project Name:Alpine Bank Location:CO, Fort Collins Project No.: Calculated By:M. Shaw Checked By:P. Dalrymple Date:12/2/20 Single-Family Alley-Loaded SF Duplex/AttachedMulti-Family 95%5%62.5%70%75%80% A-1 0.01 100 0.00 0 2 0.01 2 90 0.00 0 2% A-2R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% A-3 0.01 100 0.00 0 2 0.01 2 90 0.00 0 2% A4-R 0.06 100 0.00 0 2 0.00 0 90 0.06 90 90% B-1 0.13 100 0.09 70 2 0.04 1 90 0.00 0 71% B2-R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% B3-R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% B4-R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% B5-R 0.02 100 0.00 0 2 0.00 0 90 0.02 90 90% B6-R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% B7-R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% C-1 0.35 100 0.24 69 2 0.08 0 90 0.03 7 77% C-2R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% C-3R 0.01 100 0.00 0 2 0.00 0 90 0.01 90 90% OS-1 0.04 100 0.01 21 2 0.03 2 90 0.00 0 23% OS-2 0.08 100 0.07 79 2 0.02 0 90 0.00 0 79% OS-3 0.11 100 0.09 84 2 0.02 0 90 0.00 0 85% OS-E1 0.62 100 0.59 95 2 0.03 0 90 0.00 0 95% Basin A 0.09 -0.00 --0.02 --0.06 -67% Basin B 0.21 -0.09 --0.04 --0.08 -78% Basin C 0.37 -0.24 --0.08 --0.05 -78% WQ Chamber Tributary (A, B & C)0.67 -0.33 --0.14 --0.20 -77% Flow Leaving Site (Offsite Basins)0.23 -0.17 --0.06 --0.00 -73% Total Project Lot Area 0.90 -0.50 --0.20 --0.20 -76% COMPOSITE % IMPERVIOUSNESS - PROPOSED ALB000001.20 Asphalt + Concrete Walks Lawns, Heavy Soil: Flat <2%Building Roof % ImpBasin ID Total Area (ac)% Imp Area (ac)Area WeightedArea Weighted % Imp Area (ac)Area Weighted % Imp Area (ac) H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 3 of 8 12/1/2020 Subdivision:Alpine Bank Marketplace Project Name:Alpine Bank Location:CO, Fort Collins Project No.: Calculated By:M. Shaw Checked By:P. Dalrymple Date:12/2/20 1 BASIN D.A.Hydrologic C2 C5 C100 L S Ti | 2-Year Ti | 100-Year L S R VEL.Tt COMP. Tc | 2-Year COMP. Tc | 100-Year TOTAL Urbanized Tc Tc | 2-Year Tc | 100-Year ID (AC)Soils Group Cf=1.00 Cf=1.00 Cf=1.25 (FT)(%)(MIN)(MIN)(FT)(%)(FT)(FPS)(MIN)(MIN)(MIN)LENGTH(FT)(MIN)(MIN)(MIN) A-1 0.01 C 0.20 0.20 0.25 15 18.00 2.5 2.4 0 1.00 1.0 10.8 0.0 2.5 2.4 15 10.1 5.0 5.0 A-2R 0.01 C 0.95 0.95 1.00 20 30.00 0.4 0.3 0 1.00 1.0 10.8 0.0 0.4 0.3 20 10.1 5.0 5.0 A-3 0.01 C 0.20 0.20 0.25 5 2.00 3.0 2.8 0 1.00 1.0 10.8 0.0 3.0 2.8 5 10.0 5.0 5.0 A4-R 0.06 C 0.95 0.95 1.00 20 30.00 0.4 0.3 0 1.00 1.0 10.8 0.0 0.4 0.3 20 10.1 5.0 5.0 B-1 0.13 C 0.73 0.73 0.91 20 28.00 1.0 0.5 50 3.00 1.0 18.7 0.0 1.1 0.6 70 10.4 5.0 5.0 B2-R 0.01 C 0.95 0.95 1.00 15 30.00 0.4 0.2 0 1.00 1.0 10.8 0.0 0.4 0.2 15 10.1 5.0 5.0 B3-R 0.01 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 B4-R 0.01 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 B5-R 0.02 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 B6-R 0.01 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 B7-R 0.01 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 C-1 0.35 C 0.78 0.78 0.97 95 4.00 3.7 1.4 75 4.50 1.0 22.8 0.1 3.7 1.5 170 10.9 5.0 5.0 C-2R 0.01 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 C-3R 0.01 C 0.95 0.95 1.00 25 30.00 0.5 0.3 0 1.00 1.0 10.8 0.0 0.5 0.3 25 10.1 5.0 5.0 OS-1 0.04 C 0.36 0.36 0.45 15 4.00 3.4 3.0 0 1.00 1.0 10.8 0.0 3.4 3.0 15 10.1 5.0 5.0 OS-2 0.08 C 0.79 0.79 0.99 15 1.80 1.8 0.7 0 1.00 1.0 10.8 0.0 1.8 0.7 15 10.1 5.0 5.0 OS-3 0.11 C 0.83 0.83 1.00 25 3.80 1.6 0.6 0 1.00 1.0 10.8 0.0 1.6 0.6 25 10.1 5.0 5.0 OS-E1 0.62 C 0.91 0.91 1.00 100 2.20 2.7 1.4 60 0.50 1.0 7.6 0.1 2.9 1.6 160 10.9 5.0 5.0 NOTES: Ti = (1.87*(1.1 - CCf)*(L)^0.5)/((S)^0.33), S in % Tt=L/60V (Velocity From Fig. 501) Velocity V=(1.4/n)*(R^(2/3))*(S^0.5), S in ft/ft, R=Area/Wetted Perimeter in ft, n=Roughness Coeff., Tc Check = 10+L/180 For Urbanized basins a minimum Tc of 5.0 minutes is required. For non-urbanized basins a minimum Tc of 10.0 minutes is required (Ti) STANDARD FORM SF-2 TIME OF CONCENTRATION - PROPOSED (URBANIZED BASINS)(Tt)FINALINITIAL/OVERLAND DATA Tc CHECK ALB000001.20 TRAVEL TIMESUB-BASIN H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 4 of 8 12/1/2020 Project Name:Alpine Bank Subdivision:Alpine Bank Marketplace Project No.:ALB000001.20 Location:CO, Fort Collins Calculated By:M. Shaw Design Storm:Checked By:P. Dalrymple Date: TRAVEL TIME STREET DesignPointBasinIDArea(Ac)RunoffCoeff.|C2Tc|2-Year(min)C*A(Ac)I(in/hr)Q(cfs)Tc(min)C*A(Ac)I(in/hr)Q(cfs)Slope(%)StreetFlow(cfs)DesignFlow(cfs)Slope(%)PipeSize(inches)Length(ft)Velocity(fps)Tt(min)REMARKS A-1 0.01 0.20 5.0 0.00 2.85 0.0 NDS Area Inlet A-2R 0.01 0.95 5.0 0.00 2.85 0.0 Roof Drain A-3 0.01 0.20 5.0 0.00 2.85 0.0 Elevated Planter Box A4-R 0.06 0.95 5.0 0.06 2.85 0.2 Roof Drain B-1 0.13 0.73 5.0 0.09 2.85 0.3 CDOT Type 13 Area Inlet B2-R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain B3-R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain B4-R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain B5-R 0.02 0.95 5.0 0.02 2.85 0.1 Roof Drain B6-R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain B7-R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain C-1 0.35 0.78 5.0 0.27 2.85 0.8 CDOT Type C Area Inlet C-2R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain C-3R 0.01 0.95 5.0 0.01 2.85 0.0 Roof Drain OS-1 0.04 0.36 5.0 0.01 2.85 0.0 Sheet Flow to ex. Combo Inlet in Prospect Road OS-2 0.08 0.79 5.0 0.07 2.85 0.2 Sheet Flow to Combo Inlet in College Ave OS-3 0.11 0.83 5.0 0.09 2.85 0.3 Sheet Flow to ex. Area Inlet in alley OS-E1 0.62 0.91 5.0 0.57 2.85 1.6 Estimated area in College Ave directed to inlet Basin A 0.09 0.2 Onsite A Basins (Treated by onsite water quality) Basin B 0.21 0.5 Onsite B Basins (Treated by onsite water quality) Basin C 0.37 0.8 Onsite C Basins (Treated by onsite water quality) WQ Chamber Tributary (A, B & C) 0.67 1.5 Total Site Area Treated by Water Quality System Flow Leaving Site (Offsite Basins) 0.23 0.5 Total Uncaptured Site Area Total Project Lot Area 0.90 2.0 Total of all flows generated within property line Total Site Contribution to College Inlet 0.08 0.2 OS-2 flows to College Total Site Contribution to Prospect Inlet 0.04 0.0 OS-1 flows to Prospect Total Site Contribution to Alley Inlet 0.11 0.3 OS-3 flows to Alley (Significant reduction from ex.) College Avenue Flooding Site Bypass -0.0 Assumed no flooding entering site in 2-yr storm event per coordination with City of Fort Collins Onsite Total + Flood Flow Bypass -1.5 This is the same as the 2-yr Onsite WQ Treatment Area - shown for reference/comparison to the 100- year event DIRECT RUNOFF TOTAL RUNOFF STREET PIPE STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN - PROPOSED (RATIONAL METHOD PROCEDURE) 2-Year 12/2/20 H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 5 of 8 12/1/2020 Project Name:Alpine Bank Subdivision:Alpine Bank Marketplace Project No.:ALB000001.20 Location:CO, Fort Collins Calculated By:M. Shaw Design Storm:Checked By:P. Dalrymple Date: TRAVEL TIME STREET DesignPointBasinIDArea(Ac)RunoffCoeff.|C100Tc|100-Year(min)C*A(Ac)I(in/hr)Q(cfs)Tc(min)C*A(Ac)I(in/hr)Q(cfs)Slope(%)StreetFlow(cfs)DesignFlow(cfs)Slope(%)PipeSize(inches)Length(ft)Velocity(fps)Tt(min)REMARKS A-1 0.01 0.25 5.0 0.00 9.95 0.0 NDS Area Inlet A-2R 0.01 1.00 5.0 0.01 9.95 0.0 Roof Drain A-3 0.01 0.25 5.0 0.00 9.95 0.0 Elevated Planter Box A4-R 0.06 1.00 5.0 0.06 9.95 0.6 Roof Drain B-1 0.13 0.91 5.0 0.12 9.95 1.2 CDOT Type 13 Area Inlet B2-R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain B3-R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain B4-R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain B5-R 0.02 1.00 5.0 0.02 9.95 0.2 Roof Drain B6-R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain B7-R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain C-1 0.35 0.97 5.0 0.34 9.95 3.4 CDOT Type C Area Inlet C-2R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain C-3R 0.01 1.00 5.0 0.01 9.95 0.1 Roof Drain OS-1 0.04 0.45 5.0 0.02 9.95 0.2 Sheet Flow to ex. Combo Inlet in Prospect Road OS-2 0.08 0.99 5.0 0.08 9.95 0.8 Sheet Flow to Combo Inlet in College Ave OS-3 0.11 1.00 5.0 0.11 9.95 1.1 Sheet Flow to ex. Area Inlet in alley OS-E1 0.62 1.00 5.0 0.62 9.95 6.2 Estimated area in College Ave directed to inlet Basin A 0.09 0.7 Onsite A Basins (Treated by onsite water quality) Basin B 0.21 2.0 Onsite B Basins (Treated by onsite water quality) Basin C 0.37 3.6 Onsite C Basins (Treated by onsite water quality) WQ Chamber Tributary (A, B & C)0.67 6.3 Total Site Area Treated by Water Quality System Flow Leaving Site (Offsite Basins)0.23 2.1 Total Uncaptured Site Area Total Project Lot Area 0.90 8.4 Total of all flows generated within property line Total Site Contribution to College Inlet 0.08 0.8 OS-2 flows to College Total Site Contribution to Prospect Inlet 0.04 0.2 OS-1 flows to Prospect Total Site Contribution to Alley Inlet 0.11 1.1 OS-3 flows to Alley (Significant reduction from ex.) College Avenue Flooding Site Bypass -19.0 Assumed 19 cfs enters site after College inlet is flooded and water overtops curb to enter site. Onsite Total + Flood Flow Bypass -25.3 This is the WQ Chamber Tributary Flowrate + the offsite flooding from College entering the site. STANDARD FORM SF-3 STORM DRAINAGE SYSTEM DESIGN - PROPOSED (RATIONAL METHOD PROCEDURE) 100-Year DIRECT RUNOFF TOTAL RUNOFF STREET 12/2/20 PIPE H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 6 of 8 12/1/2020 Project Number:Alpine Bank Date:12/1/2020 Project Location:CO, Fort Collins Calculations By:M. Shaw Checked By:P. Dalrymple Pond Description:UG WQ (Underground Water Quality Facility) User Input Cell:Blue Text 1/2 2-year 0 0.79 0.00 0.67 0.76 *Release rate based on 1/2 of 2-year developed runoff ("water quality" release rate) **No additional storage required beyond WQCV - outflows exceed inflows. minutes seconds in/hr cubic feet cubic feet cubic feet acre-feet 5 300 1.43 227 228 -1 0.00 10 600 1.11 352 456 -104 0.00 15 900 0.94 447 684 -237 -0.01 20 1200 0.81 513 912 -399 -0.01 25 1500 0.72 570 1140 -570 -0.01 30 1800 0.65 622 1368 -746 -0.02 35 2100 0.59 653 1596 -943 -0.02 40 2400 0.54 682 1824 -1142 -0.03 45 2700 0.50 710 2052 -1342 -0.03 50 3000 0.46 733 2280 -1547 -0.04 55 3300 0.44 763 2508 -1745 -0.04 60 3600 0.41 784 2736 -1952 -0.04 65 3900 0.39 808 2964 -2156 -0.05 70 4200 0.37 814 3192 -2378 -0.05 75 4500 0.35 837 3420 -2583 -0.06 80 4800 0.33 841 3648 -2807 -0.06 85 5100 0.32 867 3876 -3009 -0.07 90 5400 0.31 875 4104 -3229 -0.07 95 5700 0.29 878 4332 -3454 -0.08 100 6000 0.28 892 4560 -3668 -0.08 105 6300 0.27 904 4788 -3884 -0.09 110 6600 0.26 912 5016 -4104 -0.09 115 6900 0.26 935 5244 -4309 -0.10 120 7200 0.25 937 5472 -4535 -0.10 Modified FAA Method - WQ Storage Volume Calculations Inputs | Tributary Area Output | Detention Volume Return Period for Detention Control:Required Storage, cubic feet: Catchment 'C':**Required Storage, ac-ft: Average Outflow Storage Volume Storage Volume Catchment Drainage Area, ac: *Release Rate, cfs: Storm Duration Time Rainfall Intensity Inflow Volume 0 2 4 6 8 10 12 0 20 40 60 80 100 120 140 Series1 H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 7 of 8 12/1/2020 Project Number:ALB000001.20 Date:12/1/2020 Project Location:SEC College & Prospect, Fort Collins, CO Calculations By:M Shaw Checked By:P. Dalrymple Pond Description:UG WQ (Underground Water Quality Facility) User Input Cell:Blue Text 100-year 437 1.00 0.01 0.67 *Max Allowable Release Rate, cfs:8.20 5.20 Bypass Release Rate (From College Ave), cfs:19.00 Total Release Rate (Design + Bypass), cfs:24.20 minutes seconds in/hr cubic feet cubic feet cubic feet acre-feet 5 300 9.95 1997 1560 437 0.01 10 600 7.72 3099 3120 -21 0.00 15 900 6.52 3926 4680 -754 -0.02 20 1200 5.60 4496 6240 -1744 -0.04 25 1500 4.98 4997 7800 -2803 -0.06 30 1800 4.52 5443 9360 -3917 -0.09 35 2100 4.08 5732 10920 -5188 -0.12 40 2400 3.74 6005 12480 -6475 -0.15 45 2700 3.46 6250 14040 -7790 -0.18 50 3000 3.23 6483 15600 -9117 -0.21 55 3300 3.03 6689 17160 -10471 -0.24 60 3600 2.83 6816 18720 -11904 -0.27 65 3900 2.71 7071 20280 -13209 -0.30 70 4200 2.59 7277 21840 -14563 -0.33 75 4500 2.48 7466 23400 -15934 -0.37 80 4800 2.38 7643 24960 -17317 -0.40 85 5100 2.29 7813 26520 -18707 -0.43 90 5400 2.21 7984 28080 -20096 -0.46 95 5700 2.13 8122 29640 -21518 -0.49 100 6000 2.06 8269 31200 -22931 -0.53 105 6300 2.00 8429 32760 -24331 -0.56 110 6600 1.94 8566 34320 -25754 -0.59 115 6900 1.88 8678 35880 -27202 -0.62 120 7200 1.84 8863 37440 -28577 -0.66 *The current onsite release rate entering the alley + flooding bypass (from College Avenue) is approx. 27.2 cfs per the Existing Rational Calculations, with 8.2 cfs of this being onsite runoff. The anticipated release rate has been reduced in the redevloped condition and is diverting these flows from the alley to the proposed underground water quality facility. This is reducing the existing release rate and redirecting flows away from the inundated inlet. The total release rate will be the design release rate + the bypass release rate (bypass providng additional bypass for the existing flooding condition). Average Outflow Storage Volume Storage Volume Catchment Drainage Area, ac: Design Release Rate, cfs: Storm Duration Time Rainfall Intensity Inflow Volume Modified FAA Method - 100-Year Routing Calculations Inputs | Tributary Area Output | Detention Volume Return Period for Detention Control:Required Storage, cubic feet: Catchment 'C':Required Storage, ac-ft: 0 2 4 6 8 10 12 0 20 40 60 80 100 120 140 Series1 H:\Alpine Bank\CO, Fort Collins - XXXXX - College Prospect\3 Permit CDs\3.04 Grading-Drainage Studies\3.04.2 Proposed Drainage Reports-Info\PDP 1st Sub\Rational Routing Proposed.xls Page 8 of 8 12/1/2020 Basin Area (ac)% Imp Drain Time (hrs)a WQCV Volume (ac-ft) Volume (cf) UG WQ 0.90 77%12 0.8 0.25 0.022 976 REQUIRED WATER QUALITY VOLUME WQCV Required Page 1 (i)(ii)(iii)(iv)(v)(vi)(vii)(viii)(ix)(x)(xi)(xii)(xii) Vault ID Total Required WQ Volume (cf) Flow, WQ (cfs) Chamber Type Chamber Unit Release Rate (cfs) Chamber Unit Volume (cf) Installed Chamber Unit Volume with Aggregate (cf) Minimum No. of Chambers Total Max Release Rate (cfs) Required Storage Volume by FAA Method (cf) Minimum No. of Chambers for FAA Volume Storage Provided within the Chambers (cf) Total Installed System Volume Required (cf) Actual Total Installed System Volume (cf) A 976 0.76 SC-160 0.012 6.9 15.0 66 0.792 437 64 452 990 1,263 (i)Calculated WQCV (Eq. 7-1 & 7-2) (ii)1/2 of the 2-year developed flow rate for the basin being sized (use half of the 2-year intensity for the time of concentration used in the calc - i.e. for 5 min Tc, use 1.425) (iii)Per ADS, these equate to different chamber sizes they have available. (iv)Flow rate thru the bottom of the Isolator Row chamber which is equal to the area of the bottom of the chamber multiplied by the flow rate per unit area (.35 gpm/sf). (v)Volume within chamber only, not accounting for void spaces in surrounding aggregate. (vi)Volume includes chamber and void spaces (40%) in surrounding aggregate, per chamber unit. (vii)Number of chambers required to provide full WQCV within total installed system, including aggregate. (i) / (vi) (viii)Release rate per chamber times number of chambers. (iv) * (vii) (ix)FAA calc based on Flow, WQ and Total Release Rate. Note: this additional volume is not required but is already being provided for water quality pruposes and will also allow for the 100-yr release rate to be reduced. (x)Number of chambers required to provide required FAA storage volume stored within the chamber only (no aggregate storage). (ix) / (v) (xi)Volume provided in chambers only (no aggregate storage). This number must meet or exceed the required FAA storage volume. Greater of (vii) or (x) * (v) (xii)System volume includes total number of chambers, plus surrounding aggregate. This number must meet or exceed the required WQCV. Greater of (vi) or (x) * (vi) (xiii)Actual total system volume provided with ADS design. WQ System Calculation Summary WQ System Calculations Page 2 Alpine Bank Subdivision 12/2/2020 APPENDIX C Hydraulic Computations (To Be Provided with FDP) ADVANCED DRAINAGE SYSTEMS, INC.RFOR STORMTECHINSTRUCTIONS,DOWNLOAD THEINSTALLATION APPSC-160LP STORMTECH CHAMBER SPECIFICATIONS1.CHAMBERS SHALL BE STORMTECH SC-160LP.2.CHAMBERS SHALL BE ARCH-SHAPED AND SHALL BE MANUFACTURED FROM VIRGIN, IMPACT-MODIFIED POLYPROPYLENECOPOLYMERS.3.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418-16a, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP)CORRUGATED WALL STORMWATER COLLECTION CHAMBERS".4.CHAMBER ROWS SHALL PROVIDE CONTINUOUS, UNOBSTRUCTED INTERNAL SPACE WITH NO INTERNAL SUPPORTS THAT WOULDIMPEDE FLOW OR LIMIT ACCESS FOR INSPECTION.5.THE STRUCTURAL DESIGN OF THE CHAMBERS, THE STRUCTURAL BACKFILL, AND THE INSTALLATION REQUIREMENTS SHALL ENSURETHAT THE LOAD FACTORS SPECIFIED IN THE AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS, SECTION 12.12, ARE MET FOR: 1)LONG-DURATION DEAD LOADS AND 2) SHORT-DURATION LIVE LOADS, BASED ON THE AASHTO DESIGN TRUCK WITH CONSIDERATIONFOR IMPACT AND MULTIPLE VEHICLE PRESENCES.6.CHAMBERS SHALL BE DESIGNED, TESTED AND ALLOWABLE LOAD CONFIGURATIONS DETERMINED IN ACCORDANCE WITH ASTM F2787,"STANDARD PRACTICE FOR STRUCTURAL DESIGN OF THERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS".LOAD CONFIGURATIONS SHALL INCLUDE: 1) INSTANTANEOUS (<1 MIN) AASHTO DESIGN TRUCK LIVE LOAD ON MINIMUM COVER 2)MAXIMUM PERMANENT (75-YR) COVER LOAD AND 3) ALLOWABLE COVER WITH PARKED (1-WEEK) AASHTO DESIGN TRUCK.7.REQUIREMENTS FOR HANDLING AND INSTALLATION:·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKINGSTACKING LUGS.·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESSTHAN 1.5”.·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED INSECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO 400 LBS/IN/IN. AND b) TO RESIST CHAMBER DEFORMATIONDURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE PRODUCED FROMREFLECTIVE GOLD OR YELLOW COLORS.8.ONLY CHAMBERS THAT ARE APPROVED BY THE SITE DESIGN ENGINEER WILL BE ALLOWED. UPON REQUEST BY THE SITE DESIGNENGINEER OR OWNER, THE CHAMBER MANUFACTURER SHALL SUBMIT A STRUCTURAL EVALUATION FOR APPROVAL BEFOREDELIVERING CHAMBERS TO THE PROJECT SITE AS FOLLOWS:·THE STRUCTURAL EVALUATION SHALL BE SEALED BY A REGISTERED PROFESSIONAL ENGINEER.·THE STRUCTURAL EVALUATION SHALL DEMONSTRATE THAT THE SAFETY FACTORS ARE GREATER THAN OR EQUAL TO 1.95 FORDEAD LOAD AND 1.75 FOR LIVE LOAD, THE MINIMUM REQUIRED BY ASTM F2787 AND BY SECTIONS 3 AND 12.12 OF THE AASHTOLRFD BRIDGE DESIGN SPECIFICATIONS FOR THERMOPLASTIC PIPE.·THE TEST DERIVED CREEP MODULUS AS SPECIFIED IN ASTM F2418 SHALL BE USED FOR PERMANENT DEAD LOAD DESIGNEXCEPT THAT IT SHALL BE THE 75-YEAR MODULUS USED FOR DESIGN.9.CHAMBERS AND END CAPS SHALL BE PRODUCED AT AN ISO 9001 CERTIFIED MANUFACTURING FACILITY.IMPORTANT - NOTES FOR THE BIDDING AND INSTALLATION OF THE SC-160LP SYSTEM1.STORMTECH SC-160LP CHAMBERS SHALL NOT BE INSTALLED UNTIL THE MANUFACTURER'S REPRESENTATIVE HAS COMPLETED APRE-CONSTRUCTION MEETING WITH THE INSTALLERS.2.STORMTECH SC-160LP CHAMBERS SHALL BE INSTALLED IN ACCORDANCE WITH THE "STORMTECH SC-160LP CONSTRUCTION GUIDE".3.FOUNDATION STONE AND EMBEDMENT STONE SURROUNDING CHAMBERS MUST BE A CLEAN, CRUSHED, ANGULAR STONE; AASHTO M43 #3,357, 4,467, 5, 56, OR 57.4.THE FOUNDATION STONE SHALL BE LEVELED AND COMPACTED PRIOR TO PLACING CHAMBERS.5.THE DEPTH OF FOUNDATION STONE SHALL BE DETERMINED BASED ON THE SUBGRADE BEARING CAPACITY PROVIDED BY THE SITE DESIGNENGINEER.6.THE CONTRACTOR MUST REPORT ANY DISCREPANCIES CONCERNING CHAMBER FOUNDATION DESIGN AND SUBGRADE BEARING CAPACITIES TOTHE SITE DESIGN ENGINEER.7.JOINTS BETWEEN CHAMBERS SHALL BE PROPERLY SEATED PRIOR TO PLACING STONE.8.CHAMBERS SHALL BE INSTALLED "TOE TO TOE". NO ADDITIONAL SPACING BETWEEN ROWS IS REQUIRED.9.STORMTECH RECOMMENDS 3 BACKFILL METHODS:·STONESHOOTER LOCATED OFF THE CHAMBER BED.·BACKFILL AS ROWS ARE BUILT USING AN EXCAVATOR ON THE FOUNDATION STONE OR SUBGRADE.·BACKFILL FROM OUTSIDE THE EXCAVATION USING A LONG BOOM HOE OR EXCAVATOR.10.ADS RECOMMENDS THE USE OF "FLEXSTORM CATCH IT" INSERTS DURING CONSTRUCTION FOR ALL INLETS TO PROTECT THE SUBSURFACESTORMWATER MANAGEMENT SYSTEM FROM CONSTRUCTION SITE RUNOFF.NOTES FOR CONSTRUCTION EQUIPMENT1.THE USE OF CONSTRUCTION EQUIPMENT OVER SC-160LP CHAMBERS IS LIMITED:·NO EQUIPMENT IS ALLOWED ON BARE CHAMBERS.·NO RUBBER TIRED LOADERS, DUMP TRUCKS, OR EXCAVATORS ARE ALLOWED UNTIL PROPER FILL DEPTHS ARE REACHED IN ACCORDANCEWITH THE "STORMTECH SC-160LP CONSTRUCTION GUIDE".·WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT CAN BE FOUND IN THE "STORMTECH SC-106LP CONSTRUCTION GUIDE".2.FULL 36" (900 mm) OF STABILIZED COVER MATERIALS OVER THE CHAMBERS IS REQUIRED FOR DUMP TRUCK TRAVEL OR DUMPING.CONTACT STORMTECH AT 1-888-892-2694 WITH ANY QUESTIONS ON INSTALLATION REQUIREMENTS OR WEIGHT LIMITS FOR CONSTRUCTION EQUIPMENT.©2013 ADS, INC.PROJECT INFORMATIONADS SALES REPPROJECT NO.ENGINEERED PRODUCTMANAGERALPINE BANK - SC-160FORT COLLINS, CO 520 CROMWELL AVENUE | ROCKY HILL | CT | 06067860-529-8188 |888-892-2694 | WWW.STORMTECH.COMDetention Retention Water QualityADVANCED DRAINAGE SYSTEMS, INC.R4640 TRUEMAN BLVDHILLIARD, OH 430261-800-733-7473DATE: DRAWN: EFPROJECT #: CHECKED: N/ATHIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.REVDRWCHKDESCRIPTIONALPINE BANK - SC-160FORT COLLINS, COSHEETOF25NOTES•MANIFOLD SIZE TO BE DETERMINED BY SITE DESIGN ENGINEER. SEE TECH NOTE #6.32 FOR MANIFOLD SIZING GUIDANCE.•DUE TO THE ADAPTATION OF THIS CHAMBER SYSTEM TO SPECIFIC SITE AND DESIGN CONSTRAINTS, IT MAY BE NECESSARY TO CUT AND COUPLE ADDITIONAL PIPE TO STANDARD MANIFOLDCOMPONENTS IN THE FIELD.•THE SITE DESIGN ENGINEER MUST REVIEW ELEVATIONS AND IF NECESSARY ADJUST GRADING TO ENSURE THE CHAMBER COVER REQUIREMENTS ARE MET.•THIS CHAMBER SYSTEM WAS DESIGNED WITHOUT SITE-SPECIFIC INFORMATION ON SOIL CONDITIONS OR BEARING CAPACITY. THE SITE DESIGN ENGINEER IS RESPONSIBLE FORDETERMININGTHE SUITABILITY OF THE SOIL AND PROVIDING THE BEARING CAPACITY OF THE INSITU SOILS. THE BASE STONE DEPTH MAY BE INCREASED OR DECREASED ONCE THIS INFORMATION ISPROVIDED.•NOT FOR CONSTRUCTION: THIS LAYOUT IS FOR DIMENSIONAL PURPOSES ONLY TO PROVE CONCEPT & THE REQUIRED STORAGE VOLUME CAN BE ACHIEVED ON SITE.CONCEPTUAL ELEVATIONSMAXIMUM ALLOWABLE GRADE (TOP OF PAVEMENT/UNPAVED):11.50MINIMUM ALLOWABLE GRADE (UNPAVED WITH TRAFFIC):3.17MINIMUM ALLOWABLE GRADE (UNPAVED NO TRAFFIC):2.67MINIMUM ALLOWABLE GRADE (TOP OF RIGID CONCRETE PAVEMENT):2.67MINIMUM ALLOWABLE GRADE (BASE OF FLEXIBLE PAVEMENT):2.67TOP OF STONE:2.00TOP OF SC-160LP CHAMBER:1.508" ISOLATOR ROW PLUS INVERT:0.586" BOTTOM CONNECTION INVERT:0.56BOTTOM OF SC-160LP CHAMBER:0.50UNDERDRAIN INVERT:0.00BOTTOM OF STONE:0.00PROPOSED LAYOUT69STORMTECH SC-160LP CHAMBERS20STORMTECH SC-160LP END CAPS6STONE ABOVE (in)6STONE BELOW (in)40STONE VOID1263INSTALLED SYSTEM VOLUME (CF)(PERIMETER STONE INCLUDED)(COVER STONE INCLUDED)(BASE STONE INCLUDED)1225SYSTEM AREA (SF)165.7SYSTEM PERIMETER (ft)*INVERT ABOVE BASE OF CHAMBERMAX FLOWINVERT*DESCRIPTIONITEM ONLAYOUTPART TYPE0.4 CFS OUTOCS (DESIGN BY ENGINEER / PROVIDED BY OTHERS)ACONCRETE STRUCTURE(DESIGN BY ENGINEER / PROVIDED BY OTHERS)BCONCRETE STRUCTUREW/WEIR4" ADS N-12 DUAL WALL PERFORATED HDPE UNDERDRAINCUNDERDRAINISOLATOR ROW PLUS(SEE DETAIL)NO WOVEN GEOTEXTILEBED LIMITS59.40'23.43'57.40'20.83'BCA10'5'0 MATERIAL LOCATIONDESCRIPTIONAASHTO MATERIALCLASSIFICATIONSCOMPACTION / DENSITY REQUIREMENTDFINAL FILL: FILL MATERIAL FOR LAYER 'D' STARTS FROM THE TOP OF THE 'C'LAYER TO THE BOTTOM OF FLEXIBLE PAVEMENT OR UNPAVED FINISHEDGRADE ABOVE. NOTE THAT PAVEMENT SUBBASE MAY BE PART OF THE 'D'LAYERANY SOIL/ROCK MATERIALS, NATIVE SOILS, OR PER ENGINEER'S PLANS.CHECK PLANS FOR PAVEMENT SUBGRADE REQUIREMENTS.N/APREPARE PER SITE DESIGN ENGINEER'S PLANS. PAVEDINSTALLATIONS MAY HAVE STRINGENT MATERIAL ANDPREPARATION REQUIREMENTS.CINITIAL FILL: FILL MATERIAL FOR LAYER 'C' STARTS FROM THE TOP OF THEEMBEDMENT STONE ('B' LAYER) TO 14" (355 mm) ABOVE THE TOP OF THECHAMBER. NOTE THAT PAVEMENT SUBBASE MAY BE A PART OF THE 'C'LAYER.GRANULAR WELL-GRADED SOIL/AGGREGATE MIXTURES, <35% FINES ORPROCESSED AGGREGATE. MOST PAVEMENT SUBBASE MATERIALS CAN BE USED IN LIEU OF THISLAYER.AASHTO M145¹A-1, A-2-4, A-3ORAASHTO M43¹3, 357, 4, 467, 5, 56, 57, 6, 67, 68, 7, 78, 8, 89, 9, 10BEGIN COMPACTIONS AFTER 12" (300 mm) OF MATERIAL OVERTHE CHAMBERS IS REACHED. COMPACT ADDITIONAL LAYERS IN6" (150 mm) MAX LIFTS TO A MIN. 95% PROCTOR DENSITY FORWELL GRADED MATERIAL AND 95% RELATIVE DENSITY FORPROCESSED AGGREGATE MATERIALS. ROLLER GROSSVEHICLE WEIGHT NOT TO EXCEED 12,000 lbs (53 kN). DYNAMICFORCE NOT TO EXCEED 20,000 lbs (89 kN).BEMBEDMENT STONE: FILL SURROUNDING THE CHAMBERS FROM THEFOUNDATION STONE ('A' LAYER) TO THE 'C' LAYER ABOVE.CLEAN, CRUSHED, ANGULAR STONEAASHTO M43¹3, 357, 4, 467, 5, 56, 57NO COMPACTION REQUIRED.AFOUNDATION STONE: FILL BELOW CHAMBERS FROM THE SUBGRADE UP TOTHE FOOT (BOTTOM) OF THE CHAMBER.CLEAN, CRUSHED, ANGULAR STONEAASHTO M43¹3, 357, 4, 467, 5, 56, 57PLATE COMPACT OR ROLL TO ACHIEVE A FLAT SURFACE.2,3PLEASE NOTE:1.THE LISTED AASHTO DESIGNATIONS ARE FOR GRADATIONS ONLY. THE STONE MUST ALSO BE CLEAN, CRUSHED, ANGULAR. FOR EXAMPLE, A SPECIFICATION FOR #4 STONE WOULD STATE: "CLEAN, CRUSHED, ANGULAR NO. 4 (AASHTO M43) STONE".2.STORMTECH COMPACTION REQUIREMENTS ARE MET FOR 'A' LOCATION MATERIALS WHEN PLACED AND COMPACTED IN 6" (150 mm) (MAX) LIFTS USING TWO FULL COVERAGES WITH A VIBRATORY COMPACTOR.3.WHERE INFILTRATION SURFACES MAY BE COMPROMISED BY COMPACTION, FOR STANDARD DESIGN LOAD CONDITIONS, A FLAT SURFACE MAY BE ACHIEVED BY RAKING OR DRAGGING WITHOUT COMPACTION EQUIPMENT. FOR SPECIAL LOAD DESIGNS, CONTACT STORMTECH FORCOMPACTION REQUIREMENTS.4.ONCE LAYER 'C' IS PLACED, ANY SOIL/MATERIAL CAN BE PLACED IN LAYER 'D' UP TO THE FINISHED GRADE. MOST PAVEMENT SUBBASE SOILS CAN BE USED TO REPLACE THE MATERIAL REQUIREMENTS OF LAYER 'C' OR 'D' AT THE SITE DESIGN ENGINEER'S DISCRETION.ACCEPTABLE FILL MATERIALS: STORMTECH SC-160LP CHAMBER SYSTEMSNOTES:1.CHAMBERS SHALL MEET THE REQUIREMENTS OF ASTM F2418-16a, "STANDARD SPECIFICATION FOR POLYPROPYLENE (PP) CORRUGATED WALL STORMWATER COLLECTION CHAMBERS".2.CHAMBERS SHALL BE DESIGNED, TESTED AND ALLOWABLE LOAD CONFIGURATIONS DETERMINED IN ACCORDANCE WITH ASTM F2787, "STANDARD PRACTICE FOR STRUCTURAL DESIGN OFTHERMOPLASTIC CORRUGATED WALL STORMWATER COLLECTION CHAMBERS". LOAD CONFIGURATIONS SHALL INCLUDE: 1) INSTANTANEOUS (<1 MIN) AASHTO DESIGN TRUCK LIVE LOAD ON MINIMUMCOVER 2) MAXIMUM PERMANENT (75-YR) COVER LOAD AND 3) ALLOWABLE COVER WITH PARKED (1-WEEK) AASHTO DESIGN TRUCK.3.THE SITE DESIGN ENGINEER IS RESPONSIBLE FOR ASSESSING THE BEARING RESISTANCE (ALLOWABLE BEARING CAPACITY) OF THE SUBGRADE SOILS AND THE DEPTH OF FOUNDATION STONE WITHCONSIDERATION FOR THE RANGE OF EXPECTED SOIL MOISTURE CONDITIONS.4.PERIMETER STONE MUST BE EXTENDED HORIZONTALLY TO THE EXCAVATION WALL FOR BOTH VERTICAL AND SLOPED EXCAVATION WALLS.5.REQUIREMENTS FOR HANDLING AND INSTALLATION:·TO MAINTAIN THE WIDTH OF CHAMBERS DURING SHIPPING AND HANDLING, CHAMBERS SHALL HAVE INTEGRAL, INTERLOCKING STACKING LUGS·TO ENSURE A SECURE JOINT DURING INSTALLATION AND BACKFILL, THE HEIGHT OF THE CHAMBER JOINT SHALL NOT BE LESS THAN 1.5”·TO ENSURE THE INTEGRITY OF THE ARCH SHAPE DURING INSTALLATION, a) THE ARCH STIFFNESS CONSTANT AS DEFINED IN SECTION 6.2.8 OF ASTM F2418 SHALL BE GREATER THAN OR EQUAL TO400 LBS/IN/IN. AND b) TO RESIST CHAMBER DEFORMATION DURING INSTALLATION AT ELEVATED TEMPERATURES (ABOVE 73° F / 23° C), CHAMBERS SHALL BE PRODUCED FROM REFLECTIVE GOLDOR YELLOW COLORS.DCBA*TO BOTTOM OF FLEXIBLE PAVEMENT. FOR UNPAVEDINSTALLATIONS WHERE RUTTING FROM VEHICLES MAYOCCUR, INCREASE COVER TO 20" (510 mm).6" N128" N12SC-160StormTech6" N128" N12SC-160StormTech6" N128" N12SC-160StormTech6" N128" N12SC-160StormTech6" N1 8" N12SC-160StormTechPAVEMENT LAYER (DESIGNEDBY SITE DESIGN ENGINEER)SUBGRADE SOILS(SEE NOTE 3)PERIMETER STONE(SEE NOTE 4)EXCAVATION WALL(CAN BE SLOPED OR VERTICAL)SC-160LPEND CAPNO SPACING REQUIREDBETWEEN CHAMBERS12"(300 mm)14"(350 mm)MIN*10'(3.0 m)MAX6" (150 mm) MIN12" (300 mm) MIN25"(635 mm)12" (300 mm)TYPDEPTH OF BASE STONE TO BE DETERMINEDBY SITE DESIGN ENGINEER 6" (150 mm) MINADS GEOSYNTHETICS 601T NON-WOVEN GEOTEXTILE ALLAROUND CLEAN, CRUSHED, ANGULAR STONE IN A & B LAYERS520 CROMWELL AVENUE | ROCKY HILL | CT | 06067860-529-8188 |888-892-2694 | WWW.STORMTECH.COMDetention Retention Water QualityADVANCED DRAINAGE SYSTEMS, INC.R4640 TRUEMAN BLVDHILLIARD, OH 430261-800-733-7473DATE: DRAWN: EFPROJECT #: CHECKED: N/ATHIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.REVDRWCHKDESCRIPTIONALPINE BANK - SC-160FORT COLLINS, COSHEETOF35 INSPECTION & MAINTENANCESTEP 1)INSPECT ISOLATOR ROW PLUS FOR SEDIMENTA.INSPECTION PORTS (IF PRESENT)A.1.REMOVE/OPEN LID ON NYLOPLAST INLINE DRAINA.2.REMOVE AND CLEAN FLEXSTORM FILTER IF INSTALLEDA.3.USING A FLASHLIGHT AND STADIA ROD, MEASURE DEPTH OF SEDIMENT AND RECORD ON MAINTENANCE LOGA.4.LOWER A CAMERA INTO ISOLATOR ROW PLUS FOR VISUAL INSPECTION OF SEDIMENT LEVELS (OPTIONAL)A.5.IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3.B.ALL ISOLATOR PLUS ROWSB.1.REMOVE COVER FROM STRUCTURE AT UPSTREAM END OF ISOLATOR ROW PLUSB.2.USING A FLASHLIGHT, INSPECT DOWN THE ISOLATOR ROW PLUS THROUGH OUTLET PIPEi)MIRRORS ON POLES OR CAMERAS MAY BE USED TO AVOID A CONFINED SPACE ENTRYii)FOLLOW OSHA REGULATIONS FOR CONFINED SPACE ENTRY IF ENTERING MANHOLEB.3.IF SEDIMENT IS AT, OR ABOVE, 3" (80 mm) PROCEED TO STEP 2. IF NOT, PROCEED TO STEP 3.STEP 2)CLEAN OUT ISOLATOR ROW PLUS USING THE JETVAC PROCESSA.A FIXED CULVERT CLEANING NOZZLE WITH REAR FACING SPREAD OF 45" (1.1 m) OR MORE IS PREFERREDB.APPLY MULTIPLE PASSES OF JETVAC UNTIL BACKFLUSH WATER IS CLEANC.VACUUM STRUCTURE SUMP AS REQUIREDSTEP 3)REPLACE ALL COVERS, GRATES, FILTERS, AND LIDS; RECORD OBSERVATIONS AND ACTIONS.STEP 4)INSPECT AND CLEAN BASINS AND MANHOLES UPSTREAM OF THE STORMTECH SYSTEM.NOTES1.INSPECT EVERY 6 MONTHS DURING THE FIRST YEAR OF OPERATION. ADJUST THE INSPECTION INTERVAL BASED ON PREVIOUSOBSERVATIONS OF SEDIMENT ACCUMULATION AND HIGH WATER ELEVATIONS.2.CONDUCT JETTING AND VACTORING ANNUALLY OR WHEN INSPECTION SHOWS THAT MAINTENANCE IS NECESSARY.SC-160LP ISOLATOR ROW PLUS DETAILNTSCATCH BASINORMANHOLESC-160LP CHAMBERSTORMTECH HIGHLY RECOMMENDSFLEXSTORM INSERTS IN ANY UPSTREAMSTRUCTURES WITH OPEN GRATES8" (200 mm) HDPE ACCESS PIPE REQUIRED USE 8" OPEN END CAPPART #: SC160IEPP08SC-160LP END CAPOPTIONAL INSPECTION PORTONE LAYER OF ADSPLUS125 WOVEN GEOTEXTILE BETWEENFOUNDATION STONE AND CHAMBERS4' (1.2 m) MIN WIDE CONTINUOUS FABRIC WITHOUT SEAMSSUMP DEPTH TBD BYSITE DESIGN ENGINEER(24" [600 mm] MIN RECOMMENDED)520 CROMWELL AVENUE | ROCKY HILL | CT | 06067860-529-8188 |888-892-2694 | WWW.STORMTECH.COMDetention Retention Water QualityADVANCED DRAINAGE SYSTEMS, INC.R4640 TRUEMAN BLVDHILLIARD, OH 430261-800-733-7473DATE: DRAWN: EFPROJECT #: CHECKED: N/ATHIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.REVDRWCHKDESCRIPTIONALPINE BANK - SC-160FORT COLLINS, COSHEETOF45 UNDERDRAIN DETAILNTSAABBSECTION A-ASECTION B-BDUAL WALLPERFORATEDHDPEUNDERDRAINADS GEOSYNTHETICS 601TNON-WOVEN GEOTEXTILESTORMTECH END CAPADS GEOSYNTHETICS 601TNON-WOVEN GEOTEXTILESTORMTECHCHAMBEROUTLET MANIFOLDSTORMTECH END CAPSTORMTECHCHAMBERSNUMBER AND SIZE OF UNDERDRAINS PER SITE DESIGN ENGINEER4" (100 mm) TYP FOR SC-310 & SC-160LP SYSTEMS6" (150 mm) TYP FOR SC-740, DC-780, MC-3500 & MC-4500 SYSTEMSFOUNDATION STONEBENEATH CHAMBERSFOUNDATION STONEBENEATH CHAMBERSPART #STUBASC160EPP6" (150 mm)0.66" (16 mm)8" (200 mm)0.80" (20 mm)SC160EPP088" (200 mm)0.96" (24 mm)ALL STUBS ARE PLACED AT BOTTOM OF END CAP SUCH THAT THE OUTSIDEDIAMETER OF THE STUB IS FLUSH WITH THE BOTTOM OF THE END CAP. FORADDITIONAL INFORMATION CONTACT STORMTECH AT 1-888-892-2694.NOTE: ALL DIMENSIONS ARE NOMINALNOMINAL CHAMBER SPECIFICATIONSSIZE (W X H X INSTALLED LENGTH)25.0" X 12.0" X 85.4" (635 mm X 305 mm X 2169 mm)CHAMBER STORAGE6.85 CUBIC FEET (0.19 m³)MINIMUM INSTALLED STORAGE*16.0 CUBIC FEET (0.45 m³)WEIGHT24.0 lbs.(10.9 kg)*ASSUMES 6" (152 mm) ABOVE, 6" (152 mm) BELOW, AND STONE BETWEEN CHAMBERS WITH 40% STONE POROSITY.BUILD ROW IN THIS DIRECTIONSTART ENDSC-160LP TECHNICAL SPECIFICATIONNTSSC-160StormTech6" N128" N12SC-160StormTechOVERLAP NEXT CHAMBER HERE (OVER SMALL CORRUGATION)25.0"(635 mm)12.0"(305 mm)90.7" (2304 mm) ACTUAL LENGTH85.4" (2169 mm) INSTALLED LENGTH4.4"(112 mm)A11.7"(297 mm)18.6"(472 mm)520 CROMWELL AVENUE | ROCKY HILL | CT | 06067860-529-8188 |888-892-2694 | WWW.STORMTECH.COMDetention Retention Water QualityADVANCED DRAINAGE SYSTEMS, INC.R4640 TRUEMAN BLVDHILLIARD, OH 430261-800-733-7473DATE: DRAWN: EFPROJECT #: CHECKED: N/ATHIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.REVDRWCHKDESCRIPTIONALPINE BANK - SC-160FORT COLLINS, COSHEETOF55 Project: Chamber Model - SC-160 Units -Imperial Number of chambers - 69 Voids in the stone (porosity) - 40 % Base of STONE Elevation -0.00 ft Amount of Stone Above Chambers - 6 in Amount of Stone Below Chambers - 6 in Area of system - 1225 sf Min. Area - Height of System Incremental Single Chamber Incremental Total Chamber Incremental Stone Incremental Ch & St Cumulative Chamber Elevation (inches)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(cubic feet)(feet) 24 0.00 0.00 40.83 40.83 1263.74 2.00 23 0.00 0.00 40.83 40.83 1222.91 1.92 22 0.00 0.00 40.83 40.83 1182.07 1.83 21 0.00 0.00 40.83 40.83 1141.24 1.75 20 0.00 0.00 40.83 40.83 1100.41 1.67 19 0.00 0.00 40.83 40.83 1059.57 1.58 18 0.05 3.53 39.42 42.95 1018.74 1.50 17 0.13 9.28 37.12 46.40 975.79 1.42 16 0.29 20.05 32.81 52.86 929.39 1.33 15 0.44 30.49 28.64 59.13 876.52 1.25 14 0.54 37.20 25.95 63.15 817.39 1.17 13 0.62 42.53 23.82 66.35 754.24 1.08 12 0.68 46.97 22.04 69.02 687.89 1.00 11 0.74 50.78 20.52 71.30 618.87 0.92 10 0.78 54.05 19.21 73.27 547.57 0.83 9 0.82 56.92 18.07 74.98 474.31 0.75 8 0.86 59.36 17.09 76.45 399.32 0.67 7 0.89 61.73 16.14 77.87 322.87 0.58 6 0.00 0.00 40.83 40.83 245.00 0.50 5 0.00 0.00 40.83 40.83 204.17 0.42 4 0.00 0.00 40.83 40.83 163.33 0.33 3 0.00 0.00 40.83 40.83 122.50 0.25 2 0.00 0.00 40.83 40.83 81.67 0.17 1 0.00 0.00 40.83 40.83 40.83 0.08 StormTech SC-160 Cumulative Storage Volumes 1023 sf min. area Include Perimeter Stone in Calculations Click Here for Metric Alpine Bank Subdivision 12/2/2020 APPENDIX D Drainage Maps TRASH ENCLOSURE HISTORICAL BUILDING RELOCATED PROPOSED BANK EXIT ONLY- - - - - - - - - - - - - STAMP H:\Alpine Bank\CO, Fort Collins - XXXXX - College & Prospect\CADD\3 CD\Drainage XBs\ALB001x_D_Impervious Area XB.dwg - Mike Shaw - 11/30/2020Init.#Issue / DescriptionDate THESE PLANS ARE AN INSTRUMENT OF SERVICE AND ARE THE PROPERTY OF GALLOWAY, AND MAY NOT BE DUPLICATED, DISCLOSED, OR REPRODUCED WITHOUT THE WRITTEN CONSENT OF GALLOWAY. COPYRIGHTS AND INFRINGEMENTS WILL BE ENFORCED AND PROSECUTED. COPYRIGHT GallowayUS.com 6162 S. Willow Drive, Suite 320 Greenwood Village, CO 80111 303.770.8884 PRELIMINARYNOT FOR BIDDINGNOT FOR CONSTRUCTIONDate: Drawn By: Project No: Checked By: ALB000001 OF 9UTILITY PLANS FORALPINE BANK1608 SOUTH COLLEGE AVENUES. COLLEGE AVE. & PROSPECT ROADFORT COLLINS, COLORADO 12/2/2020 1ST PDP SUB MAS DECEMBER 2020 1 IMPERVIOUS AREA EXHIBIT SCALE: 1"=20' 0 10 20 SCALE: 1"=20' 0 10 20 OF 1 - - - - - - - - - - - - - STAMP H:\Alpine Bank\CO, Fort Collins - XXXXX - College & Prospect\CADD\3 CD\Drainage XBs\ALB001x_P_11-Ex Drainage.dwg - Mike Shaw - 12/1/2020Init.#Issue / DescriptionDate THESE PLANS ARE AN INSTRUMENT OF SERVICE AND ARE THE PROPERTY OF GALLOWAY, AND MAY NOT BE DUPLICATED, DISCLOSED, OR REPRODUCED WITHOUT THE WRITTEN CONSENT OF GALLOWAY. COPYRIGHTS AND INFRINGEMENTS WILL BE ENFORCED AND PROSECUTED. COPYRIGHT GallowayUS.com 6162 S. Willow Drive, Suite 320 Greenwood Village, CO 80111 303.770.8884 PRELIMINARYNOT FOR BIDDINGNOT FOR CONSTRUCTIONDate: Drawn By: Project No: Checked By: ALB000001 OF 9UTILITY PLANS FORALPINE BANK1608 SOUTH COLLEGE AVENUES. COLLEGE AVE. & PROSPECT ROADFORT COLLINS, COLORADO 12/2/2020 1ST PDP SUB MAS DECEMBER 2020 1 EXISTING DRAINAGE MAP SCALE: 1"=20' 0 10 20 DRAINAGE BASIN BOUNDARY LINE DESIGN POINT BASIN AREA IN ACRES 100-YEAR RUNOFF COEFFICIENT BASIN DESIGNATION 2-YEAR RUNOFF COEFFICIENT FLOW ARROW 1.NO BUILDING, STRUCTURE, OR FILL WILL BE PLACED IN THE DETENTION AREAS AND CHANGES OR ALTERATIONS AFFECTING THE HYDRAULIC CHARACTERISTICS OF THE DETENTION AREAS WILL BE MADE WITHOUT THE APPROVAL OF THE CITY ENGINEER. 2.MAINTENANCE AND OPERATION OF THE DETENTION AND WATER QUALITY AREAS IS THE RESPONSIBILITY OF PROPERTY OWNER. IF OWNER FAILS IN THIS RESPONSIBILITY, THE CITY HAS THE RIGHT TO ENTER THE PROPERTY, MAINTAIN THE DETENTION AREAS, AND BE REIMBURSED FOR COSTS INCURRED. 3.DETENTION POND VOLUMES, ALL DRAINAGE APPURTENANCES, AND BASIN BOUNDARIES SHALL BE VERIFIED. AS-BUILT DRAWINGS SHALL BE PREPARED BY A REGISTERED PROFESSIONAL ENGINEER PRIOR TO ISSUANCE OF CERTIFICATE OF OCCUPANCY. 4.PERMISSION TO REPRODUCE THESE PLANS IS HEREBY GIVEN TO THE CITY OF FORT COLLINS FOR CITY PURPOSES ASSOCIATED WITH PLAN REVIEW, APPROVAL, PERMITTING, INSPECTION AND CONSTRUCTION OF THE WORK. 5.ALL PROPOSED CURB AND GUTTER FOR THE SITE SHALL BE 6" VERTICAL CURB AND GUTTER W/ A 1' PAN. NEW PROJECT BOUNDARY (EXCLUDING ALL ROW DEDICATION) OF 1 TRASH ENCLOSURE HISTORICAL BUILDING RELOCATED PROPOSED BANK EXIT ONLY- - - - - - - - - - - - - STAMP H:\Alpine Bank\CO, Fort Collins - XXXXX - College & Prospect\CADD\3 CD\ALB001x_P_11-Drainage.dwg - Mike Shaw - 12/1/2020Init.#Issue / DescriptionDate THESE PLANS ARE AN INSTRUMENT OF SERVICE AND ARE THE PROPERTY OF GALLOWAY, AND MAY NOT BE DUPLICATED, DISCLOSED, OR REPRODUCED WITHOUT THE WRITTEN CONSENT OF GALLOWAY. COPYRIGHTS AND INFRINGEMENTS WILL BE ENFORCED AND PROSECUTED. COPYRIGHT GallowayUS.com 6162 S. Willow Drive, Suite 320 Greenwood Village, CO 80111 303.770.8884 PRELIMINARYNOT FOR BIDDINGNOT FOR CONSTRUCTIONDate: Drawn By: Project No: Checked By: ALB000001 OF 9UTILITY PLANS FORALPINE BANK1608 SOUTH COLLEGE AVENUES. COLLEGE AVE. & PROSPECT ROADFORT COLLINS, COLORADO 12/2/2020 1ST PDP SUB MAS DECEMBER 2020 1 PROPOSED DRAINAGE MAP SCALE: 1"=20' 0 10 20 DRAINAGE BASIN BOUNDARY LINE DESIGN POINT BASIN AREA IN ACRES 100-YEAR RUNOFF COEFFICIENT BASIN DESIGNATION 2-YEAR RUNOFF COEFFICIENT FLOW ARROW 1.NO BUILDING, STRUCTURE, OR FILL WILL BE PLACED IN THE DETENTION AREAS AND CHANGES OR ALTERATIONS AFFECTING THE HYDRAULIC CHARACTERISTICS OF THE DETENTION AREAS WILL BE MADE WITHOUT THE APPROVAL OF THE CITY ENGINEER. 2.MAINTENANCE AND OPERATION OF THE DETENTION AND WATER QUALITY AREAS IS THE RESPONSIBILITY OF PROPERTY OWNER. IF OWNER FAILS IN THIS RESPONSIBILITY, THE CITY HAS THE RIGHT TO ENTER THE PROPERTY, MAINTAIN THE DETENTION AREAS, AND BE REIMBURSED FOR COSTS INCURRED. 3.DETENTION POND VOLUMES, ALL DRAINAGE APPURTENANCES, AND BASIN BOUNDARIES SHALL BE VERIFIED. AS-BUILT DRAWINGS SHALL BE PREPARED BY A REGISTERED PROFESSIONAL ENGINEER PRIOR TO ISSUANCE OF CERTIFICATE OF OCCUPANCY. 4.PERMISSION TO REPRODUCE THESE PLANS IS HEREBY GIVEN TO THE CITY OF FORT COLLINS FOR CITY PURPOSES ASSOCIATED WITH PLAN REVIEW, APPROVAL, PERMITTING, INSPECTION AND CONSTRUCTION OF THE WORK. 5.ALL PROPOSED CURB AND GUTTER FOR THE SITE SHALL BE 6" VERTICAL CURB AND GUTTER W/ A 1' PAN. NEW PROJECT BOUNDARY (EXCLUDING ALL ROW DEDICATION) OF 1