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HomeMy WebLinkAboutSAMS CLUB FUEL STATION - MJA200002 - SUBMITTAL DOCUMENTS - ROUND 4 - DRAINAGE REPORTPRELIMINARY DRAINAGE REPORT For: Sam’s Club Fueling Station #6633-212 4700 E Boardwalk Dr, Fort Collins, CO 80525 Rev-1 CEI Project No. 31493.0 March 26, 2021 CEI Engineering Associates, Inc. 7543 N. Ingram Ave, Suite 107 Fresno, CA 93711 559-447-3119 Fax 559-447-3129 “I hereby attest that this report for the preliminary drainage design for the Sam’s Club Fueling Station #6633-212 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.” Contents Intent of Report: ............................................................................................................................................................ 1 Drainage Requirements: ................................................................................................................................................ 1 Drainage Requirements -Variance: ................................................................................................................................ 1 Project Description: ....................................................................................................................................................... 1 Soils Description: .......................................................................................................................................................... 1 Existing Conditions: ...................................................................................................................................................... 2 Proposed Conditions: ..................................................................................................................................................... 2 Drainage Design: ........................................................................................................................................................... 3 Conclusion: .................................................................................................................................................................... 4 Appendices Appendix A Harmony Market PUD Drainage Report and Civil Plans Appendix B Calculations Exhibits Exhibit 1 Vicinity Map Exhibit 2 FIRM Map Exhibit 3 NRCS Web Soil Survey Exhibit 4 Drainage Area Map Exhibit 5 Stormwater Alternative Compliance/Variance Application Exhibit 6 Pond B - Stage Storage Table Sam’s Club Fueling Station 6633 CEI Project No. 30985 Fort Collins, CO Page 1 Intent of Report: It is the intent of this report to show that the stormwater management facilities designed for the Sam’s Club Fueling Station development described within meets or exceeds the requirements of the City of Fort Collins, and general engineering practices for the reduction of peak runoff and safe conveyance of stormwater within and/or from the site without damage to downstream property and life. Drainage Requirements: The City of Fort Collins requires LID (Low Impact Development) and Water Quality Treatment of the stormwater runoff from the proposed site, due to modifying over 1000 square feet of impervious area. The City also requires an oil spill containment system because the project is a retail gasoline outlet. Due to site constraints the engineering is not feasible to have LID on the proposed project site. In lieu of treating the runoff from the project site with LID, we are applying for a variance and will be treating a larger area to the west of the site by modifying the existing 100-year pond south of the Sam’s Club to include water quality detention. Drainage Requirements -Variance: This project is requesting a variance for the LID treatment portion of the Fort Collins Stormwater Criteria Manual Chapter 7.6.0. LID treatment of the site is infeasible due to the existing elevation difference between the surface underground stormwater piping. There is insufficient elevation difference to treat the runoff and gravity connect to the existing storm drain pipes. The proposed alternative is to add water quality detention to Pond B located behind the Sam’s Club store. This alternative will LID treat the Pond B drainage area, which is significantly larger than the proposed Fuel Station site drainage area. By treating Pond B instead of the Fuel station site, there will be more water treated than would be required for the fuel station project. Project Description: The proposed Sam’s Club Fueling Station, 4700 Boardwalk Drive, is located in the Northeastern portion of the Sam’s Club parking lot, just south of the existing Outback Steakhouse (see Exhibit 1 for Vicinity Map). The approximately 0.91-acre site currently consists of asphalt parking and landscape islands. The site is bordered on the north by Outback Steakhouse, and parking to the east and west, and Sam’s Club to the south. No portions of the Sam’s Club Fueling Station proposed development are located within the 100- year floodplain, Zone X (see Exhibit 2 for Flood Insurance Rate Map Panel #08069C1000F, December 19, 2006). Zone X is defined as Areas determined to be outside the 0.2% annual chance floodplain. Soils Description: Based on the NRCS Web Soil Survey (see Exhibit 3) the site consists entirely of Altvan-Satanta loams, (3) soils which are well drained with 0 to 3 percent slopes. The soils are moderately high Sam’s Club Fueling Station 6633 CEI Project No. 30985 Fort Collins, CO Page 2 to highly permeable (permeability rates between 0.60 to 2.00 in/hr) and a high availability to hold water. The soil typically has a depth to restrictive features of over 80 inches and a depth to water table of more than 80 inches. This soil is typically located on benches or terraces. This soil is categorized as Hydraulic Soil Group (HSG) B. Existing Conditions: The site generally slopes from north to south at approximately 1-3%. The site currently has approximately 8,214 square feet of landscape area pervious area, and approximately 31,227 square feet of impervious area. The project site has run-on flows from the existing Sam’s Club parking and Outback Steakhouse. The site also includes an existing storm area inlet. This inlet is a part of a parking lot 100-year detention basin, Pond A, that was designed to store 1.75 acre-feet of water. The GIS mapping data given by the city shows that the 18-inch ponding depth for Pond A is not the same as shown on the original Harmony Market Plans. The actual 18-inch ponding area is much smaller than shown on the original plans. Once water enters the inlet it travels down to the water quality infiltration basins at the back of the shopping center. Based on the Harmony Market PUD Drainage Report and Civil Plans (See Appendix A), the water from our site travels to Pond D located behind the Kohls and Guitar Center. CEI Engineering Associates, Inc. is not aware of nor has been made aware of flooding concerns in the vicinity of the site. Proposed Conditions: The development of the site is proposed to include the construction of a six-pump fuel station with an approximately 200 square foot kiosk, and other related site features such as paved parking and drive aisles, a spill containment system, utilities, and landscape improvements as required by the City of Fort Collins. The proposed development site is approximately 0.80 acres. The site will have approximately 8,292 square feet of landscaped pervious area, and a total impervious area of approximately 31,149 square feet. This is a decrease of 78 square feet of impervious area. There is approximately 7,948 square feet of total modified impervious area. There is 6,787 square feet of asphalt impervious surfaces that will be modified to be either concrete or roof impervious areas. There is 1,161 square feet of asphalt impervious areas that is being updated to landscaped pervious areas. There is approximately 0.45 acres of off-site run on primarily from the north, that is about 92 percent impervious. Due to the limitations of the site, the proposed area cannot feasibly be treated on site. The area to the south west of the site that drains into Pond B has a drainage area of approximately 8.94 acres. The proposed area treatment swap includes adding water quality detention to the existing Pond B. The 8.94 acres draining to Pond B is larger than the 1.36 acres that makes up the proposed site and has approximately 6.9 acres of impervious area. The water quality area swap is treating a larger area than required for this development. Sam’s Club Fueling Station 6633 CEI Project No. 30985 Fort Collins, CO Page 3 Table: Existing and Design Volumes for Pond A and Pond B Pond Original Design Volume (CF) Current Existing Volume (CF) Proposed Volume (CF) Pond A 76,500 20,115 18,823 Pond B 85,925 44,383 45,683 Drainage Design: The site was analyzed using the methods described in the Fort Collins Stormwater Criteria Manual. The site hydraulic conditions are not changing significantly, so the same sized grating and pipe sizes will be used to match existing conditions. The design includes a new spill containment vault with an oil stop valve to prevent oil from entering the stormwater system. The containment vault has approximately 150 gallons of storage capacity for oil. The water quality capture volume (WQCV) was calculated to be 1663 cubic feet, this includes the volume from the off-site run on from the north (See Calculations in Appendix B). The runoff from the site will continue to drain to Pond D. Based on the existing Harmony Market PUD Drainage Report, Pond D is sized for the 100-year storm for about 5.6 acres. Pond D was designed to store 50,400- cubic feet of water and is already providing the 100-year detention for the site without any known maintenance or sizing concerns. The post development impervious area is lower than existing; therefore, Pond D is still sufficiently sized to provide 100-year detention of the site’s stormwater runoff. Pond A is a 100-year parking lot detention pond, that was originally sized to store approximately 1.76 acre-feet of water. Pond A was designed to pond up to a depth of 1.5 feet, per the 1989 Harmony Market Drainage Plan. The current existing max ponding depth is approximately 1.79 feet. Fort Collins requires the max ponding depth to be 1.5 feet or less. The spill over point for Pond A is in the middle drive aisle on the east side of the site, this area will be re-graded to return the max ponding depth to no more than 1.5 feet. The proposed fueling station is impacting the storage of Pond A, removing approximately 1,292 cubic feet of storage. This storage is being added to Pond B behind the Sam’s Club to maintain the amount of storage that currently exists. Due to the limitations of the site, the WQCV will be captured off the project site. The area to the southwest that drains into Pond B, located south of the Sam’s Club, has a drainage area of 8.94 acres, and a WQCV of 12,139 cubic feet; which is greater than the project site’s WQCV of 1,663 cubic feet. This volume will be treated within the existing 100-year Pond B. To treat the water an extended detention outlet will be added to the existing pond outlet. This outlet consists of an orifice plate to reduce the water quality detention time to 40 hours. For storms above the water quality storm, a grated overflow will be included at the max elevation of the water quality storage volume (4994.65 ft elevation) to allow the 100-year storm to pass as originally designed. Sam’s Club Fueling Station 6633 CEI Project No. 30985 Fort Collins, CO Page 4 Conclusion: The proposed development of the Sam’s Club Fueling Station in the Sam’s Club Parking Lot at 4700 Boardwalk Drive, meets the general provisions of the City of Fort Collins requirements and general engineering practices with regards to the management of stormwater. This report has been prepared in general accordance with the current requirements of the applicable storm water jurisdictions and approving agencies. In addition, storm events/frequencies, runoff calculations, discharge criteria, evaluation methods (including computer software applications), etc., have been based on the guidelines/requirements of these permitting entities and reflect the application of generally accepted standard of engineering practice. This design is based on, and limited by, the weather data, the analysis and their applicability as presented herein. AAPPPPEENNDDIIXX AA HHaarrmmoonnyy MMaarrkkeett PPUUDD DDrraaiinnaaggee RReeppoorrtt aanndd CCiivviill PPllaannss AAPPPPEENNDDIIXX BB CCaallccuullaattiioonnss SF AcresPervious Area (SF)C=0.25Impervious Area (SF)C=0.95 C Pervious % Impervious %Total Area59225 1.36 9735 49490 0.83 16% 84%Onsite Area39441 0.91 8214 31227 0.80 21% 79%Offsite Area19784 0.45 1521 18263 0.90 8% 92%Total Area59225 1.36 9813 49412 0.83 17% 83%Onsite Area39441 0.91 8292 31149 0.80 21% 79%Offsite Area19784 0.45 1521 18263 0.90 8% 92%Net impervious Change-78 SFaDrain time (12 Hour)0.8I83%WQCVa(0.91*I3 - 1.19*I2 + 0.78I)0.281 INAAcres1.36ACV(WQCV/12)*A*1.20.038AC-FT1663CFWater Quality Capture Volume (inches)Catchment AreaRequired Volume Required WQCV (Fuel Station) Fuel Station Project Site Drainage AreaPrePostCoefficient corresponding to WQCV drain Time (Table 5.4-1)Imperviousness (%/100) SF AcresPervious Area (SF)C=0.25Impervious Area (SF)C=0.95 C Pervious % Impervious %Pre Total Area389502 8.94 88794 300708 0.79 23% 77%Post Total Area389502 8.94 88794 300708 0.79 23% 77%aDrain time (40 Hours)1I77%WQCVa(0.91*I3 - 1.19*I2 + 0.78I)0.312 INAAcres8.94ACV(WQCV/12)*A*1.20.279AC-FT12139CFPond B Drainage AreaRequired WQCV Required Volume Catchment AreaImperviousness (%/100)Coefficient corresponding to WQCV drain Time (Table 5.4-1)Water Quality Capture Volume (inches) EEXXHHIIBBIITT 11 VViicciinniittyy MMaapp Vici nity M ap Sam 's Club Fueling Station 1000 ft N➤➤N © 2020 Google© 2020 Google Project Site EEXXHHIIBBIITT 22 FFIIRRMM MMaapp USGS The National Map: Orthoimagery. Data refreshed April, 2019. National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250Feet Ü105°4'7.37"W 40°31'34.14"N 105°3'29.91"W 40°31'6.79"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOODHAZARD AR EAS Without Base Flood Elevation (BFE)Zone A, V, A99With BFE or Depth Zone AE, AO, AH, VE, AR Regulator y Floodway 0.2% Annual Chance Flood Hazard, Areasof 1% annual chance flood with averagedepth less than one foot or with drainageareas of less than one square mile Zone X Future Conditions 1% AnnualChance Flood Hazard Zone XArea with Reduced Flood Risk due toLevee. See Notes.Zone X Area with Flood Risk due to Levee Zone D NO SCREE N Area of Minimal Flood Hazard Zone X Area of Undetermined Flood Hazard Zone D Channel, Culver t, or Storm SewerLevee, Dike, or Floodwall Cross Sections with 1% Annual Chance17.5 Water Surface ElevationCoastal Transect Coastal Transect BaselineProfile BaselineHydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of StudyJurisdiction Boundar y 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 theauthoritative NFHL web ser vices provided by FEMA. This mapwas exported on 4/13/2020 at 3:19:38 PM and does notreflect changes or amendments subsequent to this date andtime. The NFHL and effective information may change orbecome superseded by new data over time. This map image is void if the one or more of the following mapelements 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 forunmapped and unmodernized areas cannot be used forregulatory purposes. Legend OTHER AREAS OFFLOOD HAZARD OTHER AREAS GENERALSTRUCTURES OTHERFEATURES MAP PANELS 8 1:6,000 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative proper ty location. EEXXHHIIBBIITT 33 NNRRCCSS WWeebb SSooiill SSuurrvveeyy 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 April 13, 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 Soil Map..................................................................................................................5 Soil Map................................................................................................................6 Legend..................................................................................................................7 Map Unit Legend..................................................................................................8 Map Unit Descriptions..........................................................................................8 Larimer County Area, Colorado......................................................................10 3—Altvan-Satanta loams, 0 to 3 percent slopes.........................................10 Soil Information for All Uses...............................................................................13 Soil Properties and Qualities..............................................................................13 Soil Qualities and Features.............................................................................13 Hydrologic Soil Group.................................................................................13 References............................................................................................................18 4 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. 5 6 Custom Soil Resource Report Soil Map 448572044857304485740448575044857604485770448578044857904485800448572044857304485740448575044857604485770448578044857904485800494600 494610 494620 494630 494640 494650 494660 494600 494610 494620 494630 494640 494650 494660 40° 31' 22'' N 105° 3' 49'' W40° 31' 22'' N105° 3' 46'' W40° 31' 19'' N 105° 3' 49'' W40° 31' 19'' N 105° 3' 46'' 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: 1:452 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 14, Sep 13, 2019 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 7 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes 1.0 100.0% Totals for Area of Interest 1.0 100.0% 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 8 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 9 Larimer County Area, Colorado 3—Altvan-Satanta loams, 0 to 3 percent slopes Map Unit Setting National map unit symbol: jpw2 Elevation: 5,200 to 6,200 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 Altvan and similar soils: 45 percent Satanta and similar soils: 30 percent Minor components: 25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Altvan Setting Landform: Benches, terraces Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium Typical profile H1 - 0 to 10 inches: loam H2 - 10 to 18 inches: clay loam, loam, sandy clay loam H2 - 10 to 18 inches: loam, fine sandy loam, silt loam H2 - 10 to 18 inches: gravelly sand, gravelly coarse sand, coarse sand H3 - 18 to 30 inches: H3 - 18 to 30 inches: H3 - 18 to 30 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: H4 - 30 to 60 inches: Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 13.2 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Custom Soil Resource Report 10 Hydrologic Soil Group: B Hydric soil rating: No Description of Satanta Setting Landform: Terraces, structural benches Landform position (three-dimensional): Side slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Mixed alluvium and/or eolian deposits Typical profile H1 - 0 to 9 inches: loam H2 - 9 to 18 inches: loam, clay loam, sandy clay loam H2 - 9 to 18 inches: loam, clay loam, fine sandy loam H2 - 9 to 18 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: H3 - 18 to 60 inches: Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Available water storage in profile: Very high (about 27.4 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Hydric soil rating: No Minor Components Nunn Percent of map unit: 10 percent Hydric soil rating: No Larim Percent of map unit: 10 percent Hydric soil rating: No Stoneham Percent of map unit: 5 percent Hydric soil rating: No Custom Soil Resource Report 11 Custom Soil Resource Report 12 Soil Information for All Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest. A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer. These features can greatly impact the use and management of the soil. Hydrologic Soil Group Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. 13 Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Custom Soil Resource Report 14 15 Custom Soil Resource Report Map—Hydrologic Soil Group 448572044857304485740448575044857604485770448578044857904485800448572044857304485740448575044857604485770448578044857904485800494600 494610 494620 494630 494640 494650 494660 494600 494610 494620 494630 494640 494650 494660 40° 31' 22'' N 105° 3' 49'' W40° 31' 22'' N105° 3' 46'' W40° 31' 19'' N 105° 3' 49'' W40° 31' 19'' N 105° 3' 46'' 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: 1:452 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 Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Larimer County Area, Colorado Survey Area Data: Version 14, Sep 13, 2019 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 16 Table—Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 3 Altvan-Satanta loams, 0 to 3 percent slopes B 1.0 100.0% Totals for Area of Interest 1.0 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Custom Soil Resource Report 17 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 18 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 19 EEXXHHIIBBIITT 44 DDrraaiinnaaggee MMaapp KIOSK 200± SF FFE 5000.05covered cart returncovered cart returnEueueuemb500150005 0 0 04999 4999499949994998499849974998 4999ONSITEDRAINAGEAREA0.91 ACRESOFFSITEDRAINAGE AREA0.42 ACRES2.5%2. 6 %1.2%2.7%5.8 %2.0%1.9%2.0%2.0%(1.2%)±(1. 6 % ) ±(1.7%)±(1.8%)±(4.9%)±(3.9%)±(1.9%)±1.2%1.2%OFFSITE DRAINAGEAREA = 0.03 ACRESALERT TO CONTRACTOR:ALL SAM'S CLUB GENERAL CONTRACTOR WORK TO BE COMPLETED(EARTHWORK, FINAL UTILITIES, AND FINAL GRADING) BY THE MILESTONE DATEIN PROJECT DOCUMENTS.SCALE IN FEET60'45'30'0DATE Engineering Associates, Inc.REVISIONSDRWDESPMDPORINITIAL DESIGNC7.19:24 AM2/8/21DRAINAGE MAP EXHIBIT 4700 BOARDWALK DRIVE COLORADOFORT COLLINS FAX: (559) 447-3129 (559) 447-3119 Fresno, CA 93711 710 W. Pinedale Ave.JAPJAPJPDJDG5/19/2020SAM'S CLUB FUEL STATION #6633-212 3149331493-DRJOB # 31493 DRAWING: 31493-DR.dwg LAST SAVED BY: AVANDERGRIFT Know what'sbelow.before you dig.CallNOTE:SEE ARCHITECTURAL PLANS FOR EXACT LOCATIONS AND DIMENSIONS OFPORCHES, RAMPS, VESTIBULE, SLOPED PAVING, TRUCK DOCKS, BUILDINGUTILITY ENTRANCE LOCATIONS AND PRECISE BUILDING DIMENSIONS.SITE BENCHMARK:CITY OF FORT COLLINS BENCHMARK: 4-08 ON SOUTH SIDE OF HARMONY RD. AT THE NORTHWEST CORNER OF 625 EASTHARMONY RD. (FRONT RANGE BAPTIST CHURCH), ON THE NORTH WALL OF ACONCRETE IRRIGATION DROP STRUCTURE. NAVD88=5017.14' 5/19/2020INITIAL DESIGNSITE FEATURESDRAINAGE BOUNDARYFLOW PATH2.0%SURFACE FLOW(2.0%)±EXISTING SURFACE FLOW KIOSK 200± SF FFE 5000.05covered cart returncovered cart returnTEMPORARY ONSITE BENCHMARKIRON PIPE IN ASPHALT HOLEELEV 5000.297'N 1433734.81993'E 3121499.21743'ESW W W 1''WDN08° 50' 22"W 2 1 5 . 9 6 ' L =7 7 .1 6 ,R =5 6 5 .9 6 Δ =7 .8 1 N80° 29' 24"E 20.16'N80° 29' 24"E 99.48'L=79.74,R=1 0 0 . 0 0Δ=45. 6 9 N 3 4 ° 4 8 ' 0 9 " E 1 1 8 . 1 6 ' L = 9 5 .31,R=100.00Δ=54.61N89° 24' 31"E 263.86'S00° 00' 00"E 714.30'N90° 00' 00"E 117.28'S00° 00' 01"E 308.47'L=205.82,R=576.00Δ=20.47N68° 30' 20"W 150.28'L=155.43,R=451.94Δ=19.70N85° 15' 16"W 66.41'N88° 12' 35"W 107.00'L=17.28, R=11.00 Δ=90 N01° 47' 25"E 255.44' L =11 9 .4 7 ,R =6 4 3 .9 7Δ=1 0 .6 3 wwcovered cart returncovered cart returnasphaltconcrete sidewalk 20' AUE10' AUE wueueueuembREGRADE EXISTING BASIN TO ACCOMMODATE VOLUME LOST IN POND A E HARMONY ROADS BOARDW A L K D R I V E SAM'S CLUB KOHL'SOAKRIDGE DRIVE501 2 501 1 501 0 500 9 5 0 0 8 5 0 0 7 5 0 0 6 5 0 0 5 500450035002501 3 501 450135012501150105009500850075006500550 0 4 50 0 2 50 0 1 50 0 0 4999499849974999499949964998499749954995499649974998499949944994 4995 4996 49 9 7 4998 49974997499949984997 49 9 9 50 0 0 50 0 1 50 0 2 5 0 0 3 5 0 0 4 5 0 0 5 5 0 0 6 5 0 0 7 5 0 0 8 5 0 0 9 49984997 4997 499849995000500150025003500449 9 9 49 9 8 49 9 7 49 9 6 49 9 5 EXISTING DRAIN INLET USED TO CALCULATE MAXIMUM 18 INCHES PONDING LIMITS AS SHOWN IN "HARMONY MARKET P.U.D., FILING ONE FINAL" DRAINAGE REPORT, DATED MARCH 13, 1989, REVISED APRIL 24, 1989) DRAINAGE AREA FOR POND B 8.94 ACRES 120% WQCV ELEVATION: 4994.65' APPROX LOCATION POND A OVERTOP ELEVATION: 4997.85 (APPOX 1.50' PONDING DEPTH) EXISTING POND A TOP OF BASIN: 4997.85± BOTTOM OF BASIN: 4996.35± EXISTING VOLUME:20,115 CF (0.46 AC-FT) PROPOSED VOLUME:18,823 CF (0.43 AC-FT) (MAX 18 INCH PONDING PER "HARMONY MARKET P.U.D., FILING ONE FINAL" DRAINAGE REPORT, DATED MARCH 13, 1989, REVISED APRIL 24, 1989) 4997.85 4997.85 4997.85 APPROX PONDING AREA LOST TO FUEL STATION DEVELOPMENT APPROX PONDING AREA ADDED TO FUEL STATION DEVELOPMENT 4 9 9 7 . 8 5 4993499280'0 120'160' SCALE IN FEET DATE Engineering Associates, Inc.REVISIONS DRWDESPMDPOR INITIAL DESIGN EX12:28 PM 3/17/21 EXISTING POND A & B EXHIBIT4700 BOARDWALK DRIVECOLORADOFORT COLLINSFAX: (559) 447-3129(559) 447-3119Fresno, CA 93711710 W. Pinedale Ave.JAPJAPJPDJDG 5/19/2020SAM'S CLUB FUEL STATION #6633-21231493 31493-GIS JOB # 31493 DRAWING: 31493-GIS.dwg LAST SAVED BY: JOEPERKINSKnow what's below. before you dig.Call EXISTING CONDITIONS - POND B STAGE STORAGE TABLE ELEV AREA (sq. ft.) AVG END INC. VOL. (cu. ft.) AVG END TOTAL VOL. (cu. ft.) AVG END TOTAL VOL. (ac. ft.) CONIC INC. VOL. (cu. ft.) CONIC TOTAL VOL. (cu. ft.) CONIC TOTAL VOL. (ac. ft.)NOTE 4,992.00 0.01 N/A 0.00 0.0000 N/A 0.00 0.000 4,993.00 1,967.49 983.75 983.75 0.0226 657.32 657.32 0.0151 4,994.00 8,423.84 5195.66 6179.41 0.1419 4820.81 5478.13 0.1258 4,994.65 14,788.52 N/A 12,227.70 0.2807 N/A 12,227.59 0.2807 120% WQCV ELEVATION 4,995.00 20,248.47 14336.15 20515.57 0.4710 13910.85 19388.97 0.4451 4,996.00 27,486.70 23867.58 44383.15 1.0189 23775.59 43164.56 0.9909NOTE: EXISTING CONTOUR DATA SHOWN HEREON ARE FROM GIS DATA PROVIDED BY CITY OF FORT COLLINS, CO. ORIGINAL DESIGN - POND B STAGE STORAGE TABLE ELEV AREA (sq. ft.) INCREMENTAL VOLUME (cu. ft.) CUMULATIVE VOLUME (cu. ft.) CUMULATIVE VOLUME (ac. ft.) 4,989.50 0.00 0 0 0 4990.00 3,200 800 800 0.0200 4992.00 24,800 28,000 28,800 0.6600 4,993.50 29,900 41,025 69,825 1.6000 4,994.00 34,500 16,100 85,925 1.9700 LEGEND EXISTING CONTOUR PROPOSED POND B EXPANSION AREA (2,600± SF - 1,300± CF) APPROXIMATE TOP OF POND B (TOP ELEVATION: 4,996.00±) APPROXIMATE WATER QUALITY CAPTURE VOLUME (WQCV) (TOP ELEVATION: 4,994.65±) APPROXIMATE LIMITS OF EXISTING POND A (TOP ELEVATION: 4,997.85±) APPROXIMATE LIMITS OF PROPOSED POND A (TOP ELEVATION: 4,997.85±) EEXXHHIIBBIITT 55 SSttoorrmmwwaatteerr AAlltteerrnnaattiivvee CCoommpplliiaannccee//VVaarriiaannccee AApppplliiccaattiioonn Stormwater Alternative Compliance/Variance Application City of Fort Collins Water Utilities Engineering Section A: Engineer/Owner Information Engineer Name____________________________________________Phone___________________________ Street Address_____________________________________________________________________________ City__________________________________________State________________________Zip_____________ Owner Name______________________________________________Phone___________________________ Street Address_____________________________________________________________________________ City__________________________________________State________________________Zip_____________ Section C: Alternative Compliance/Variance Information Section B: Proposed Project Information Legal description and/or address of property____________________________________________________ Project Name______________________________________________________________________________ Project/Application Number from Development Review (i.e. FDP123456)__________________________ Description of Project_______________________________________________________________________ __________________________________________________________________________________________ Existing Use (check one): ☐ residential ☐ non-residential ☐ mixed-use ☐ vacant ground Proposed Use (check one): ☐ residential ☐ non-residential ☐ mixed-use ☐ other____________________ If non-residential or mixed use, describe in detail_______________________________________________ __________________________________________________________________________________________ __________________________________________________________________________________________ State the requirement from which alternative compliance/variance is sought. (Please include applicable Drainage Criteria Manual volume, chapter and section.) What hardship prevents this site from meeting the requirement? What alternative is proposed for the site? Attach separate sheet if necessary Attach separate sheet if necessary page 2 The owner agrees to comply with the provisions of the zoning ordinance, building code and all other applicable sections of the City Code, Land Use Code, City Plan and all other laws and ordinances affecting the construction and occupancy of the proposed building that are not directly approved by this variance. The owner understands that if this variance is approved, the structure and its occupants may be more susceptible to fl ood or runoff damage as well as other adverse drainage issues. Signature of owner:_____________________________________________Date:_______________________ The engineer hereby certifi es that the above information, along with the reference plans and project descriptions is correct. Signature of engineer:___________________________________________Date:_______________________ PE STAMP If you have questions or need assistance fi lling out forms, contact Fort Collins Utilities at: Phone: 970-221-6700 · TDD 970-224-6003 Web: fcgov.com/stormwater · Email: WaterUtilitiesEng@fcgov.com UtilitiesOffice use onlyDate complete application submitted:_____________ Date of approval/denial:__________________________ Variance: ☐ approved ☐ denied Staff justifi cation/notes/conditions:_______________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ ________________________________________________________________________________________ Approved by:__________________________________ Entered in UtilityFile Database? ☐ yes ☐ no EEXXHHIIBBIITT 66 PPoonndd BB -- SSttaaggee SSttoorraaggee TTaabbllee ELEVAREA(sq. ft.)AVG ENDINC. VOL.(cu. ft.)AVG ENDTOTAL VOL.(cu. ft.)AVG ENDTOTAL VOL(ac. ft.)CONICINC. VOL.(cu. ft.)CONICTOTAL VOL.(cu. ft.)CONICTOTAL VOL.(ac. ft.)NOTE4,992.000.01N/A00N/A00 4,993.001,967.49983.75983.750.0226657.32657.320.0151 4,994.008,423.845195.666179.410.14194820.815478.130.1258 4,994.6514,788.52N/A12,227.700.2807N/A12,227.590.2807120% WQCV ELEVATION4,995.0020,248.4714336.1520515.570.47113910.8519388.970.4451 4,996.0027,486.7023867.5844383.151.018923775.5943164.560.9909 ELEVAREA(sq. ft.)INCREMENTAL VOLUME(cu. ft.)CUMULATIVE VOLUME(cu. ft.)CUMULATIVE VOLUME(ac. ft.)4,989.5000004,990.003,2008008000.024,992.0024,80028,00028,8000.664,993.5029,90041,02569,8251.64,994.0034,50016,10085,9251.97EXISTING CONDITIONS - POND B STAGE STORAGE TABLEORIGINAL DESIGN - POND B STAGE STORAGE TABLE