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HomeMy WebLinkAbout1516 REMINGTON ST FRATERNITY SORORITY APU - PDP200017 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT 19 OLD TOWN SQUARE #238 | FORT COLLINS, CO 80524 | 970-530-4044 | www.unitedcivil.com 1516 REMINGTON ST. Lots 3 & 4, Block 7 L C Moore’s 2nd Addition Fort Collins, CO Prepared for: Beta Tau 1919 House Corporation 633 17th St, 3000 Denver, CO 80202 Date: November 4, 2020 PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO i U20018_Drainage Report.docx November 4, 2020 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: 1516 Remington St. Improvements Fort Collins, Colorado Project Number: U20018 Dear Staff: United Civil Design Group, LLC. is pleased to submit this Preliminary Drainage Report for the 1516 Remington St. site in Fort Collins, Colorado. In general, this report serves to document the stormwater impacts associated with the proposed improvements related to the existing site. We understand that review by the City of Fort Collins is to assure general compliance with standardized criteria contained in the Fort Collins Stormwater Criteria Manual (FCSCM). This report was prepared in compliance with technical criteria set forth in both the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual and the Fort Collins Stormwater Criteria Manual. If you should have any questions or comments as you review this report, please feel free to contact us at your convenience. Sincerely, United Civil Design Group Colton Beck, PE Sam Eliason, PE Project Engineer Principal PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO ii U20018_Drainage Report.docx TABLE OF CONTENTS I. General Location and Description ...................................................................................................................................... 1 A. Location and Project Description ................................................................................................................ 1 B. Description of Property ............................................................................................................................... 2 C. Floodplains .................................................................................................................................................. 2 II. Drainage Basins and Sub-Basins ......................................................................................................................................... 3 A. Major Basin Description .............................................................................................................................. 3 B. Sub-Basin Description ................................................................................................................................. 3 III. Drainage Design Criteria ..................................................................................................................................................... 3 A. Regulations ................................................................................................................................................. 3 B. Directly Connected Impervious Area (DCIA) ............................................................................................... 3 C. Hydrological Criteria ................................................................................................................................... 3 D. Hydraulic Criteria ........................................................................................................................................ 4 E. Modifications of Criteria ............................................................................................................................. 4 IV. Drainage Facility Design ..................................................................................................................................................... 4 A. General Concept ......................................................................................................................................... 4 B. Specific Details ............................................................................................................................................ 4 V. Erosion Control ................................................................................................................................................................... 6 VI. Conclusions ........................................................................................................................................................................ 7 A. Compliance with Standards ........................................................................................................................ 7 B. Drainage Concept........................................................................................................................................ 7 C. Stormwater Quality..................................................................................................................................... 7 VII. References ...................................................................................................................................................................... 8 APPENDICES APPENDIX A – Hydrology Calculations APPENDIX B – Hydraulic Calculations B.1 – Low Impact Development Calculations B.2 – Water Quality Calculations B.3 – Sidewalk Chase Calculations (Reserved for Final Submittal) APPENDIX C – Referenced Materials APPENDIX D – Drainage Exhibits PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 1 U20018_Drainage Report.docx I. GENERAL LOCATION AND DESCRIPTION A. LOCATION AND PROJECT DESCRIPTION The 1516 Remington St. property (referred herein as “the site”) exists as Lot 3 and 4, Block 7, L C Moore’s 2nd Addition, located in the southwest quarter of Section 13, T7N, R69W of the 6th P.M., City of Fort Collins, Larimer County, Colorado. The property, consisting of approximately 0.39 acres, is located north of East Prospect Rd and south of East Lake St. The site currently exists as a vacant residential property with on-site parking. The proposed 1516 Remington St. improvements are limited to approximately 0.25 acres of disturbed area. The property is bounded by residential properties to the north and south, public right-of-way to the west (Remington St.) and public right-of-way to the east (alleyway). Stormwater on the site currently drains to either Remington St or the alleyway, though all stormwater eventually drains existing inlet at the intersection of Remington St. and E Lake St. Ultimately the site drains to the Spring Creek in accordance with the City of Fort Collins Spring Creek master drainage basin. The proposed improvements to the site consist of redesigning and reconstructing a portion of the site’s drive lane and parking area. Improvements are proposed to associated landscaping and walks adjacent to the building. Additionally, low impact development and water quality measures are proposed with the site improvements in the form of permeable pavers. FIGURE 1: SITE VICINITY MAP This drainage report presents the overall drainage plan for the development. In general, this report serves to provide an analysis of the drainage impacts associated with the site improvements as it relates to existing and proposed drainage features on-site. E Prospect Rd S College Ave Remington St E Lake St PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 2 U20018_Drainage Report.docx B. DESCRIPTION OF PROPERTY The project site currently exists as a fully developed residential lot, including concrete and asphalt pavement, sidewalks, rooftop, and landscaping, comprising of an existing imperviousness of 51.0%. In its existing condition, by means of sheet flow, the site ultimately drains off-site to public right-of-way west and east of the site. Below are summaries of key components of the site in its existing conditions. Land Use - The site’s current land use is residential. Ground Cover - The site exists as a residential lot with concrete and asphalt pavement, sidewalk, rooftop, and surrounding grass landscaping. The grass cover is good (ie., heavy or dense cover with nearly all ground surfaces protected by vegetation). Existing Topography – The site slopes in multiple directions away from the existing on-site building, however, runoff ultimately drains west and east to an existing downstream inlet associated with Remington St. Grades – In general, the western portion of the site is sloped westerly at approximately 1.0% to 8.0%; the eastern portion of the site slopes easterly at approximately 1.0% to 3.0%. Public right-of-way immediately west and east of the site conveys water to the north at approximately 1.0% to 2.5%. Soil Type - The USDA’s Web Soil Survey shows that the site consists of “Type C” soils, namely Fort Collins loam (3% to 5% slopes). The on-site soils provide moderate infiltration and are suitable for development. Utilities – The following dry utility lines run along the south side of the site: gas, electric, and fiber optic. A 12” water main exists in Remington St while a sanitary sewer main exists in an alleyway east of the site. Drainage Features and Storm Sewer – An off-site inlet exists north of the site at the intersection of Remington St. and E Lake St. C. FLOODPLAINS The 1516 Remington St. property is not in a FEMA designated floodplain. According to the FEMA Flood Insurance Rate Map Panel, the site is zoned as an area outside of the 500-year floodplain. The FEMA FIRM Panel # is 08069C0979H, effective 5/2/2012, which is included with Appendix C. FIGURE 2: FLOODPLAIN MAP 1516 Remington St. PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 3 U20018_Drainage Report.docx II. DRAINAGE BASINS AND SUB-BASINS A. MAJOR BASIN DESCRIPTION The existing site is located within the Spring Creek master drainage basin. No known master planning improvements are associated with or adjacent to the site. B. SUB-BASIN DESCRIPTION The site is not analyzed with any known drainage reports. In its improved condition, runoff from the site will largely follow existing drainage patterns, though the area of runoff directed east to the existing alleyway is reduced. Provided the reduction of area draining to the alleyway, a minor increase of on-site area drains westerly to Remington St. III. DRAINAGE DESIGN CRITERIA A. REGULATIONS The design criteria for this study are directly from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards Manual and the Urban Storm Drainage Criteria Manuals Volumes 2, and 3 (referred to herein as USDCM). B. DIRECTLY CONNECTED IMPERVIOUS AREA (DCIA) With the adoption of the USDCM, the City has also adopted the “Four Step Process” that is recommended in Volume 3 of the USDCM in selecting structural BMPs for the redeveloping urban areas. The following portions of this summary describe each step and how it has been utilized for this project: Step 1 – Employ Runoff Reduction Practices The objective of this step is to reduce runoff peaks and volumes and to employ the technique of “minimizing directly connected impervious areas” (MDCIA). This project accomplishes this by: Routing the roof and pavement flows to permeable pavers to promote infiltration and provide water quality. Step 2 – Provide Water Quality Capture Volume (WQCV) The objective of providing WQCV is to reduce the sediment load and other pollutants that exit the site. For this project WQCV is provided within permeable paver sections. Step 3 – Stabilize Drainageways The use of LID will help slow runoff from the site and benefit the stabilization of downstream drainageways. In addition, this project will pay stormwater development and stormwater utility fees which the City uses, in part, to maintain the stability of the City drainageway systems. Step 4 – Consider Need for Site Specific and Source Control BMPs Site specific and source control BMPs are generally considered for large industrial and commercial sites. The redevelopment of the existing site will include multiple site specific and source controls, including:  Dedicated maintenance personnel providing landscape maintenance and snow and ice management. C. HYDROLOGICAL CRITERIA City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, provided by Figure RA-16 of the Fort Collins Stormwater Criteria Manual, are utilized for all hydrologic computations related to the site in its existing/historic and proposed conditions. Since this site is relatively small and does not have complex drainage basins, the peak flow rates for design points have been calculated based on the Rational Method as described in the USDCM and the City of Fort Collins Stormwater Criteria Manual (FCSCM) with storm duration set equal to the time of concentration for each sub-basin. This method was used to analyze the developed runoff from the 2-year (minor) and the 100-year (major) storm events. The Rational Method is widely accepted PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 4 U20018_Drainage Report.docx for drainage design involving small drainage areas (less than 160 acres) and short time of concentrations. Runoff coefficients are assumed based on impervious area and are given in the Appendices. D. HYDRAULIC CRITERIA The developed site will convey runoff to existing public right-of-way via sheet flow. The City of Fort Collins Stormwater Criteria Manual (FCSCM) and USDCM are referenced for all hydraulic calculations. Microsoft Excel is utilized in providing runoff and water quality computations. Drainage conveyance facility capacities proposed with the development project, including permeable pavers, are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District’s Urban Storm Drainage Criteria Manual (UDFCD). E. MODIFICATIONS OF CRITERIA The drainage design of the 1516 Remington St. improvements does not vary from City of Fort Collins criteria. IV. DRAINAGE FACILITY DESIGN A. GENERAL CONCEPT Developed runoff is designed to largely maintain existing drainage patterns. Runoff that drains off-site is ultimately conveyed to an existing inlet at the intersection of Remington St. and E Lake St. Per City standards, stormwater detention is not being provided because the increase in impervious surfaces is less than 1,000 square-feet. Also per City standards, water quality and low impact development (LID) is being proposed with project to mitigate the impervious areas that are being modified with the development. Water quality and LID systems provided with the improvements include several permeable paver sections around the property. B. SPECIFIC DETAILS Hydrology Site improvements include an increase of approximately 796 sf of additional impervious area relative to existing conditions. Due to the minimal impacts related to the site’s overall imperviousness (i.e. less than 1,000 sf), the proposed improvements are not expected to negatively impact the existing nearby hydraulic features. The table on the following page summarizes the hydrologic impact associated with the proposed site improvements relative to existing conditions. Refer to the drainage exhibits and hydrology calculations attached for additional information. 1516 Remington St. Existing Proposed Overall Area (acre) 0.39 0.39 *Roof (sf) 3,687 3,717 *Asphalt (sf) 2,577 - *Concrete (sf) 2,618 5,443 *Permeable Pavers (sf) - 1,386 *Landscape (sf) 8,118 6,454 % Imperviousness 51.0% 56.2% Composite C2 0.62 0.65 Composite C100 0.77 0.81 TABLE 1 - HYDROLOGIC SUMMARY PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 5 U20018_Drainage Report.docx For purposes of Low Impact Development (LID) calculations, hydrology calculations related to the “modified” site area (limited to 0.13 acres of site modifications) are included in Appendix B. On-site Basins The following basins provide drainage delineations for the site in its existing and improved condition. Refer to Appendix A for hydrology computations and Appendix B for calculations related to Water Quality and Low Impact Development features. Basin EX Sub-basins EX1 and EX2 (see Drainage Plan attached) represent on-site drainage basins as they historically exist. These basins divide the existing site as it related to existing grading. These basins consist of roof area, asphalt and concrete paving, and landscaping. Runoff within these basins is conveyed to the east and west via sheet flow. Basin PR Sub-basins PR1 and PR2 represent on-site drainage basins related to the property in its improved condition. These basins divide the site similar to that of existing sub-basins, though with minor changes in delineation due to proposed grading. These basins consist of roofs, concrete, landscaping, and permeable pavers. Similar to existing conditions, runoff is conveyed to public right-of-way via sheet flow. Stormwater Quality & Low Impact Development (LID) In December of 2015, Fort Collins City Council adopted the revised Low Impact Development (LID) policy and criteria which requires developments within City limits to meet certain enhanced stormwater treatment requirements in addition to more standard treatment techniques. The proposed development will be required to meet the newly adopted LID criteria which requires the following: - Treat no less than 75% of any newly added impervious area using one or a combination of LID techniques. - Treat no less than 50% of any newly added impervious area using one or a combination of LID techniques when at least 25% of any newly added pavement is provided with permeable pavement. The following measures are implemented with this proposed development: I. Permeable Pavers Permeable pavers are a space-saving LID method used for walking and driveway surfaces. Porosity in the area between pavers allows stormwater to drain into a subsurface storage layer for treatment and infiltration. Permeable pavers are proposed with the site improvements in several sections, providing water quality for upstream run-on impervious areas. The inclusion of Permeable pavers is designed to satisfy all water quality and low impact development requirements per City of Fort Collins criteria. Water quality and LID calculations are provided in Appendix B. Below provides a summary of water quality and low impact development calculations as they relate to City of Fort Collins criteria. Water Quality Required: Total New or Modified Impervious Area = 4,593 sf Required LID Water Quality Treatment = 2,297 sf (50% minimum) Water Quality Provided: Permeable Pavers (Standard Water Quality & LID) = 1,386 sf Total Impervious Area Treated = 4,754 sf Detention Detention is not being provided with the redevelopment of the site because the net increase in impervious surfaces is less than 1,000 square-feet. PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 6 U20018_Drainage Report.docx Standard Operating Procedures (SOPs) In order for physical stormwater Best Management Practices (BMPs) to be effective, proper maintenance is essential. Maintenance includes both routinely scheduled activities, as well as non-routine repairs that may be required after large storms, or as a result of other unforeseen problems. Standard Operating Procedures should clearly identify BMP maintenance responsibility. BMP maintenance is typically the responsibility of the entity owning the BMP. Identifying who is responsible for maintenance of BMPs and ensuring that an adequate budget is allocated for maintenance is critical to the long-term success of BMPs. Maintenance responsibility may be assigned either publicly or privately. For this project, the privately owned BMPs including grass swales and the bioretention pond, are to be maintained by the property owner. Storm Sewer Aside from underdrains system associated with proposed permeable paver sections, there is no storm sewer infrastructure provided with the site improvements. Inlets There are no inlets associated with the site improvements. On-site runoff is designed to drain off-site to an existing inlet at the intersection of Remington St. and E Lake St. Minor changes in stormwater runoff to Remington St. and the east alleyway are negligible; hydraulic calculations of off-site features are not provided with this report. Sidewalk Chase In an effort to prevent roof stormwater from draining across a patio designed with the site improvements, a sidewalk chase is proposed as an alternate method of conveyance. Approximately 880 sf of roof area is designed to be conveyed to this 1-ft wide chase. A hydraulic analysis of this sidewalk chase will be provided with a final drainage report. V. EROSION CONTROL Erosion control, both temporary and permanent, is a vital part of any development project. For this project, the site disturbance is less than 1 acre; therefore, a CDPHE Stormwater Management Plan (SWMP) is not required. However, comprehensive erosion control measures are included with the site improvements. Refer to the Utility Plans for additional information. At a minimum, the following temporary BMP’s will 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.  Rock Socks – Similar to wattles, rock socks are designed to prevent soil and debris from draining further downstream to storm infrastructure. They are a temporary BMP and require proper installation and maintenance to ensure their performance. 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. Temporary Best Management Practices (BMP’s) will be inspected by the contractor at a minimum of once every two weeks and after each significant storm event. PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 7 U20018_Drainage Report.docx VI. CONCLUSIONS A. COMPLIANCE WITH STANDARDS Storm drainage calculations have followed the guidelines provided by the Urban Storm Drainage Criteria Manuals Volumes 1, 2 and 3 and the City of Fort Collins Stormwater Criteria Manual. B. DRAINAGE CONCEPT The drainage system has been designed to convey the runoff to the designated design points and the existing public infrastructure in an effective, safe manner. No negative impacts are anticipated to the City of Fort Collins Master Drainage Plan or to downstream properties or infrastructure due to the proposed improvements. C. STORMWATER QUALITY Long-term stormwater quality measures in the form of permeable pavers have been selected for the site that will provide treatment of stormwater prior it to being discharged from the site. PRELIMINARY DRAINAGE REPORT 1516 REMINGTON ST. FORT COLLINS, CO 8 U20018_Drainage Report.docx VII. REFERENCES 1. City of Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, November 2017. 2. Urban Storm Drainage Criteria Manual Volume 1 and 2, Urban Drainage and Flood Control District, Denver, Colorado, June 2001, Revised April 2008. 3. Natural Resources Conservation Service Web Soil Survey at: websoilsurvey.nrcs.usda.gov/app 4. Flood Insurance Rate Map, FEMA, Panel 08069C0979H, https://hazards.fema.gov/femaportal/ 5. Stormwater Discharges Associated with Construction Activity, Stormwater Management Plan Preparation Guides, State of Colorado, www.colorado.com APPENDIX A HYDROLOGY CALCULATIONS RUNOFF COEFFICIENTS AND % IMPERVIOUS 1516 Remingtion St, Fort Collins, CO Basin Design Pt. Total Total Roof (1) Asphalt Concrete (1) Gravel (1) Lawns (10(3) Composite Effective C2 C 100 %I = 90% %I = 100% %I = 100% %I =40% %I=2% Imperviousness Impervious C=0.95 C=0.95 C=0.95 C=0.50 C=0.25 Areas acres sf sf sf sf sf sf (%) sf EX-MA Modified Area 0.13 5,838 76 2,577 1,108 2,077 65.0% 3,795 0.70 0.88 EX-Site Site 0.39 17,000 3,687 2,577 2,618 8,118 51.0% 8,676 0.62 0.77 - - - - - EX1 EX1 0.23 10,095 1,685 151 1,996 6,263 37.5% 0.52 0.64 EX2 EX2 0.16 6,905 2,002 2,426 622 1,855 70.8% 0.76 0.95 Basin Design Pt. Total Total Roof (1) Asphalt Concrete (1) Pavers (1) Lawns (10(3) Composite Effective C2 C 100 acres sf %I = 90% %I = 100% %I = 100% %I =40% %I=2% Imperviousness Impervious C=0.95 C=0.95 C=0.95 C=0.50 C=0.25 Areas sf sf sf sf sf (%) sf PR-MA Modified Area 0.13 5,838 106 3,933 1,386 413 78.6% 4,591 0.79 0.99 PR-Site Site 0.39 17,000 3,717 5,443 1,386 6,454 55.7% 9,472 0.65 0.81 PR1 PR1 0.24 10,410 1,791 2,727 388 5,504 44.2% 0.56 0.70 PR2 PR2 0.15 6,590 1,926 2,716 998 950 73.9% 0.78 0.98 30 (2,577) 2,825 1,386 (1,664) 13.6% 796 30 (2,577) 2,825 1,386 (1,664) 4.7% 796 Notes: (1) Recommended % Imperviousness Values per Table 4.1-3 Surface Type - Percent Impervious in Fort Collins Stormwater Criteria Manual (2) Runoff C is based Table 3.2-2. Surface Type - Runoff Coefficients and Table 3.2-3. Frequency Adjustment Factors in Fort Collins Stormwater Manual (3) Runoff C for Lawns based off of Lawns, Clayey Soil, Avg Slope 2-7% Difference between Proposed and Existing Modified Areas Difference between Proposed and Existing Site Composite Runoff Coefficients Areas (2) Existing Basins Proposed Basins Areas Composite Runoff Coefficients (2) Date: 10/20/2020 C:\United Civil Dropbox\Projects\U20018 - 1516 Remington St\Reports\Drainage\Calculations\U20018-Drain Calcs.xlsm TIME OF CONCENTRATION 1516 Remingtion St, Fort Collins, CO Basin Design Pt. Area Initial Ground C5 (1) Length Slope ti (2) Length Slope Cv Velocity (3) tt (4) Check tc? Total Length tc (5) acres Type ft % min ft % fps min min Urban? ft min min EX1 EX1 0.23 Roof 0.73 25 2.0% 2.7 70 7.0% 15 4.0 0.3 3.0 Yes 95 11 5.0 EX2 EX2 0.16 Roof 0.73 25 2.0% 2.7 60 2.5% 20 3.2 0.3 3.0 Yes 85 10 5.0 Basin Design Pt. Area Initial Ground C5 (1) Length Slope ti (2) Length Slope Cv Velocity (3) tt (4) Check tc? Total Length tc (5) acres Type ft % min ft % fps min min Urban? ft min min PR1 PR1 0.24 Roof 0.73 25 2.0% 2.7 70 7.0% 15 4.0 0.3 3.0 Yes 95 11 5.0 PR2 PR2 0.15 Roof 0.73 25 2.0% 2.7 60 3.0% 20 3.5 0.3 2.9 Yes 85 10 5.0 Notes: (1) C5 based initial ground type and Table 6-4 (2)ti = [0.395(1.1-C5)L1/2]/S1/3, S= slope in %, L=length of overland flow (300' max urban, 500' max rural) (3)V=KS0.5, S=watercourse slope in ft/ft, UDFCD Equation 6-4 (4)tt=L/(V*60 sec/min) (5)tc check (for urban or developed areas only) = total length/180 + 10 (6)min tc = 5 min Existing Basins Proposed Basins Initial Overland Flow Time (ti) Travel/Channelized Time of Flow (tt) ti+tt tc Check for Urbanized Basins Final tc (6) ti+tt Final tc (6) Initial Overland Flow Time (ti) Travel/Channelized Time of Flow (tt) tc Check for Urbanized Basins Date: 10/20/2020 C:\United Civil Dropbox\Projects\U20018 - 1516 Remington St\Reports\Drainage\Calculations\U20018-Drain Calcs.xlsm RATIONAL METHOD PEAK RUNOFF 1516 Remingtion St, Fort Collins, CO Basin Design Pt. Area Final acre tc (6) C2 C5 C100 I2 I5 I100 Q2 Q5 Q100 min in/hr in/hr in/hr cfs cfs cfs EX1 EX1 0.23 5 0.52 0.52 0.64 2.85 3.97 9.95 0.34 0.47 1.49 EX2 EX2 0.16 5 0.76 0.76 0.95 2.85 3.97 9.95 0.34 0.48 1.50 0.68 2.12 2.99 Basin Design Pt. Area Final acre tc (6) C2 C5 C100 I2 I5 I100 Q2 Q5 Q100 min in/hr in/hr in/hr cfs cfs cfs PR1 PR1 0.24 5 0.56 0.56 0.70 2.85 3.97 9.95 0.38 0.53 1.67 PR2 PR2 0.15 5 0.78 0.78 0.98 2.85 3.97 9.95 0.34 0.47 1.47 0.72 1.00 3.14 Existing Basins Totals Totals Peak Discharge Proposed Basins Runoff Coefficients Rainfall Intensity Peak Discharge RunoffIntensity Coefficients Rainfall Date: 10/20/2020 C:\United Civil Dropbox\Projects\U20018 - 1516 Remington St\Reports\Drainage\Calculations\U20018-Drain Calcs.xlsm APPENDIX B HYDRAULIC CALCULATIONS WATER QUALITY - LOW IMPACT DEVELOPMENT 1516 Remingtion St, Fort Collins, CO Water Quality & LID Requirements Basin Area Area Roof Asphalt Concrete Pavers (sf) (acres) (sf) (sf) (sf) (sf) PR-MA 5,838 0.134 106 0 3,933 1,386 Total New or Modified Impervious Area for Water Quality Treatment*: 4593 sf 50% to be treated by LID Water Quality: 2297 sf *Impervious Areas calculated based on all of the new or modified asphalt, concrete, and roof areas and 40% of new or modified pervious paver areas Permeable Pavers Provided (Water Quality & LID) Permeable Paver Section #1 Paver Section Area: 220 sf Run-on Area for Paver Section #1: 305 sf Ratio: 1.4 : 1 Permeable Paver Section #2 Paver Section Area: 168 sf Run-on Area for Paver Section #2: 463 sf Ratio: 2.8 : 1 Permeable Paver Section #3 Paver Section Area: 601 sf Run-on Area for Paver Section #3: 1418 sf Ratio: 2.4 : 1 Permeable Paver Section #4 Paver Section Area: 396 sf Run-on Area for Paver Section #4: 1180 sf Ratio: 3.0 : 1 Total Water Quality Provided Total Impervious Area Treated by Permeable Pavers: 4754 sf Total % of Water Quality Treatment by Permeable Pavers: 103% Date: 10/20/2020 C:\United Civil Dropbox\Projects\U20018 - 1516 Remington St\Reports\Drainage\Calculations\U20018-Drain Calcs.xlsm APPENDIX C REFERENCED MATERIALS USGS The National Map: Orthoimagery. Data refreshed April 2020 National Flood Hazard Layer FIRMette 0 250 500 1,000 1,500 2,000 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 SCREENArea 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 10/14/2020 at 2:40 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 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, Colorado 1516 Remington St Natural Resources Conservation Service October 14, 2020 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 4490800 4490810 4490820 4490830 4490840 4490850 4490800 4490810 4490820 4490830 4490840 4490850 493620 493630 493640 493650 493660 493670 493680 493690 493700 493620 493630 493640 493650 493660 493670 493680 493690 493700 40° 34' 6'' N 105° 4' 31'' W 40° 34' 6'' N 105° 4' 27'' W 40° 34' 4'' N 105° 4' 31'' W 40° 34' 4'' N 105° 4' 27'' W N 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: 1:423 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil 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 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 36 Fort Collins loam, 3 to 5 percent slopes 0.9 100.0% Totals for Area of Interest 0.9 100.0% Map Unit Descriptions 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, onsite investigation is needed to define and locate the soils and miscellaneous areas. Custom Soil Resource Report 11 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 36—Fort Collins loam, 3 to 5 percent slopes Map Unit Setting National map unit symbol: 2yqpg Elevation: 4,800 to 5,900 feet Mean annual precipitation: 13 to 15 inches Mean annual air temperature: 48 to 50 degrees F Frost-free period: 135 to 150 days Farmland classification: Prime farmland if irrigated Map Unit Composition Fort collins and similar soils: 80 percent Minor components: 20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Fort Collins Setting Landform: Alluvial fans, terraces Landform position (three-dimensional): Tread Down-slope shape: Linear, convex Across-slope shape: Linear Parent material: Pleistocene or older alluvium and/or eolian deposits Typical profile Ap - 0 to 5 inches: loam Bt1 - 5 to 8 inches: clay loam Bt2 - 8 to 18 inches: clay loam Bk1 - 18 to 24 inches: loam Bk2 - 24 to 80 inches: loam Properties and qualities Slope: 3 to 5 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): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: R067BY002CO - Loamy Plains Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Table mountain Percent of map unit: 15 percent Landform: Stream terraces, alluvial fans Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY036CO - Overflow Hydric soil rating: No Larim Percent of map unit: 5 percent Landform: Alluvial fans Down-slope shape: Linear Across-slope shape: Linear Ecological site: R067BY063CO - Gravel Breaks 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 APPENDIX D DRAINAGE EXHIBITS LEGEND BUILDING/ROOF AREA ASPHALT CONCRETE PROPERTY BOUNDARY LIMITS OF MODIFIED IMPERVIOUS AREA LIMITS OF MODIFIED IMPERVIOUS AREA 1516 REMINGTON ST REMINGTON ST PATH: 0' 20' 40' SCALE: 1" = 20' 10' C:\UNITED CIVIL DROPBOX\PROJECTS\U20018 - 1516 REMINGTON ST\CADD\ET\EXISTING IMPERVIOUS EXHIBIT.DWG DRAWING NAME: EXISTING IMPERVIOUS EXHIBIT SHEET SIZE: 11 x 17 1516 REMINGTON STREET EXISTING SITE IMPERVIOUS AREA EXHIBIT DATE: October 26, 2020 PREPARED FOR: BETA TAU 1919 HOUSE CORP. JOB NUMBER: U20018 NOTE: THIS EXHIBIT WAS PREPARED FOR INFORMATION ONLY AND THE ENGINEER PREPARING THESE PLANS WILL NOT BE RESPONSIBLE FOR UNAUTHORIZED USE OF THEM. 19 OLD TOWN SQUARE, # 238 FORT COLLINS, CO 80524 (970) 530-4044 WWW.UNITEDCIVIL.COM SHEET 1 OF 2 UNITED CIVIL Design Group LLC NORTH BASIN AREAS COMPOSITE EFFECTIVE COMPOSITE FRUNOFF COEFFICIENTS TOTAL TOTAL ROOF ASPHALT CONCRETE GRAVEL LAWNS IMPERVIOUSNESS IMPERVIOUS %I = 0% %I = 100% %I = 100% %I =0% %I=2% (%I) AREAS C2 C100 (ACRES) sf sf sf sf sf sf EX-SITE 0.39 17,000 3,687 2,577 2,618 8,118 51.0% 8,676 0.62 0.77 Compact Compact Compact Compact Compact Compact Compact LEGEND BUILDING/ROOF AREA ASPHALT CONCRETE PROPERTY BOUNDARY LIMITS OF MODIFIED IMPERVIOUS AREA LIMITS OF MODIFIED IMPERVIOUS AREA 1516 REMINGTON ST PERMEABLE PAVERS REMINGTON ST PATH: 0' 20' 40' SCALE: 1" = 20' 10' C:\UNITED CIVIL DROPBOX\PROJECTS\U20018 - 1516 REMINGTON ST\CADD\ET\PROPOSED IMPERVIOUS EXHIBIT.DWG DRAWING NAME: PROPOSED IMPERVIOUS EXHIBIT SHEET SIZE: 11 x 17 1516 REMINGTON STREET PROPOSED SITE IMPERVIOUS AREA EXHIBIT DATE: October 27, 2020 PREPARED FOR: BETA TAU 1919 HOUSE CORP. JOB NUMBER: U20018 NOTE: THIS EXHIBIT WAS PREPARED FOR INFORMATION ONLY AND THE ENGINEER PREPARING THESE PLANS WILL NOT BE RESPONSIBLE FOR UNAUTHORIZED USE OF THEM. 19 OLD TOWN SQUARE #238, FORT COLLINS, CO 80524 (970) 530-4044 WWW.UNITEDCIVIL.COM SHEET 2 OF 2 UNITED CIVIL Design Group LLC NORTH BASIN AREAS COMPOSITE EFFECTIVE COMPOSITE FRUNOFF COEFFICIENTS TOTAL TOTAL ROOF ASPHALT CONCRETE PAVERS LAWNS IMPERVIOUSNESS IMPERVIOUS %I = 0% %I = 100% %I = 100% %I =0% %I=2% (%I) AREAS C2 C100 (ACRES) sf sf sf sf sf sf PR-SITE 0.39 17,000 3,717 5,443 1386 6,454 55.7% 9,471 0.65 0.81 Compact Compact Compact Compact Compact Compact Compact REMINGTON STREET (104' R.O.W) 1504 REMINGTON STREET 1520 REMINGTON STREET EXISTING BUILDING 1516 REMINGTON STREET EXISTING ALLEY EXISTING DRIVEWAY R.O.W LINE FFE=5003.30 FFE=5001.63 FFE=5003.30 PR1 0.24 0.56 0.70 EX1 0.23 0.52 0.64 EX2 0.16 0.76 0.95 PR2 0.15 0.78 0.98 PERMEABLE PAVER SECTION 1 PERMEABLE PAVER SECTION 2 PERMEABLE PAVER SECTION 3 PERMEABLE PAVERSECTION 4 BETA TAU 1919 HOUSE CORP. 11/4/2020 U20018 1" = 10' 1" = N/A 1516 REMINGTON STREET NORTH 11/3/2020 3:36:52 PM C:\UNITED CIVIL DROPBOX\PROJECTS\U20018 - 1516 REMINGTON ST\CADD\CP\C5.00_DRAINAGE PLAN.DWG C5.00_DRAINAGE PLAN CDB CDB C5.00 8 DRAINAGE PLAN 0 10' 20' SCALE: 1" = 10' 5' PREPARED FOR: JOB NUMBER SHEET NUMBER OF SHEETS DATE SUBMITTED: VERTICAL: HORIZONTAL: SCALE PRELIMINARY PLANS NOT FOR CONSTRUCTION PROJ. MGR: DRAWING NAME: PATH: DATE: TIME: DESIGNER: The engineer preparing these plans will not be responsible for, or liable for, unauthorized changes to or uses of these plans. All changes to the plans must be in writing and must be approved by the preparer of these plans. NO. BY DATE CAUTION REVISIONS: CIVIL ENGINEERING & CONSULTING UNITED CIVIL Design Group 19 OLD TOWN SQUARE #238 FORT COLLINS, CO 80524 (970) 530-4044 www.unitedcivil.com 8 CHECKED BY: CHECKED BY: CHECKED BY: CHECKED BY: APPROVED: CHECKED BY: EXISTING BASIN DESIGNATION BASIN AREA (ACRE) 2 - YR RUNOFF COEFF. 100 - YR RUNOFF COEFF. FLOW DIRECTION LEGEND EXISTING BASIN BOUNDARY PROPOSED BASIN BOUNDARY PERMEABLE PAVEMENT TREATMENT AREA X.XX XX.X X.XX X PROPOSED BASIN DESIGNATION BASIN AREA (ACRE) 2 - YR RUNOFF COEFF. 100 - YR RUNOFF COEFF. X XX.X X.XX X.XX DRAINAGE SUMMARY Basin Area %I C2 C 100 Q2 Q 100 (acre) (cfs) (cfs) Existing Basins EX1 0.23 37.5% 0.52 0.64 0.34 1.49 EX2 0.16 70.8% 0.76 0.95 0.34 1.50 Proposed Basins PR1 0.24 44.2% 0.56 0.70 0.38 1.67 PR2 0.15 73.9% 0.78 0.98 0.34 1.47 WATER QUALITY SUMMARY WATER QUALITY REQUIREMENT: TOTAL NEW OR MODIFIED IMPERVIOUS AREA = 4,593 SF REQUIRED LID WQ TREATMENT = 2,297 SF (50% MIN) WATER QUALITY PROVIDED: PERMEABLE PAVERS (LID) = 4,754 SF 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 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°4'48"W 40°34'19"N 105°4'11"W 40°33'52"N