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HomeMy WebLinkAboutMAVERIK - FDP210003 - SUBMITTAL DOCUMENTS - ROUND 4 - DRAINAGE REPORT Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 1 Final Drainage Report for Maverik Inc. Store I-25 & North County Road 32 (Hwy 392) Fort Collins, Colorado 80528 # PERMIT NO. Prepared for: Maverik, Inc. 185 South State Street Suite 800 Salt Lake City, Utah 84111 Prepared by: DCI Engineers 1331 17th Street, Suite 605 Denver, Colorado (720) 464-7728 DCI Job No. 19-122-0006 July 28, 2021 Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 2 Engineer’s Certification: I hereby affirm that this report and plan for the final drainage design for Maverick Fuel Station Fort Collins was prepared by me, or under my direct supervision, for the owners thereof, in accordance with the provision for City of Fort Collins Stormwater Criteria Manual (2017), and approved variances and exceptions thereto. I understand that they the City of Fort Collins does not and will not assume liability for drainage facilities designed by others. By: Harry Jones, P.E. Licensed Professional Engineer State of Colorado No. 52959 Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 3 Developer’s Certification: Maverik, Inc. hereby certifies that the drainage facilities for the Maverick Fuel Station Fort Collins shall be constructed according to the design presented in this report. I understand that the City of Fort Collins does not and will not assume liability for the drainage facilities designed and/or certified by my engineer and that the City of Fort Collins reviews drainage plans pursuant to Colorado Revised Statutes; but cannot, on behalf of Maverik, Inc. guarantee that final drainage design review will absolve Maverik, Inc. and/or their successors and/or assigns of future liability for improper design. I further understand that approval of the Final Drainage Report does not constitute approval of my engineer’s final drainage design. Name Authorized Signature Cassie Younger Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 4 SECTION 1. GENERAL LOCATION AND EXISTING SITE INFORMATION SITE LOCATION The proposed Maverick Fuel Station is located in the City of Fort Collins, within Larimer County in Colorado. The proposed 2.84-acre plot of land is comprised of one parcel #8615305702 with East County Road 32/Highway 392 to the South, Interstate 25 to the east, and SW Frontage Road, a federal right-of-way, to the North. Fossil Creek Reservoir is Northwest of the site. The proposal includes 9 standard fuel dispensers and 6 hi-flow commercial diesel dispensers. A total of 28 off- street parking spaces will be provided. Access is taken from SW Frontage Rd to the northwest. The property is within the I-25/State Highway 392 Corridor Activity Center in the General Commercial (CG) Zoning District and is subject to Planning and Zoning Board (Type 2) Review. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 5 TOWNSHIP, RANGE SECTION AND ¼ SECTION The Colorado State Land Board maintains records of the Cadastral Survey of the state for purposes of establishing legal property boundaries in proposed land subdivisions. The proposed property is located in a portion of the SW ¼ of Section 15, Township 6 North, Range 68 West, of the 6th Principal Meridian in the State of Colorado. A survey was performed by Altura Land Consultants dated May 15, 2019, last revised June 3, 2019. The legal description, as identified on the Title Survey from Altura Land Consultants, is as follows: Lot 2, Interstate Land Holdings Minor Land Subdivision File No. 12-S3124, City of Fort Collins, County of Larimer, State of Colorado The proposed development is located within the boundary of the City of Fort Collins, within Larimer County in Colorado. The site is bordered by East County Road 32/Highway 392 to the South, Interstate Highway 25 to the East, and SW Frontage Road, a federal right-of-way, to the West-Northwest. Proposed driveway connections and improvements shall be subject to the review and approval of the Interstate Land Holdings Minor Land Division. The parcel is located in the General Commercial zoning district. Adjacent lots around the subject property consist of vacant lots and commercial uses. The Fossil Creek Reservoir is located northwest of the property. DESCRIPTION OF PROPERTY The proposed development consists of 2.841 acres of undeveloped property. The site consists of one parcel #8615305702. An analysis by DCI Engineers using a modified rational method indicates a weighted impervious percentage of 71.6% for the complete build out. Under the criteria of Table 4.1-2 and 3 from Chapter 5 of the Fort Collins Stormwater Criteria Manual, areas within the development were separated into categories. Roofs were assigned an impervious percentage of 95%, sidewalks and asphalt pavements received a 95% percent categorization, and lawn and landscaped areas were assigned a 2% weighted impervious percentage. The resulting calculations can be found in Appendix A Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 6 At full build out, the proposed site includes approximately 2.13 acres of proposed impervious area, including rooftops, roadways, and paved sidewalk/courtyard areas. Approximately 6,662 cubic yards of soil will be removed and replaced or exported with the current proposed plan. The development will increase the impervious area by the full 75% (from the existing undeveloped land). The site currently consists of undeveloped property covered with low-lying vegetation. The land generally drains to the northwest with an approximate change in elevation of ten feet over a horizontal distance of 350 feet towards the interstate ramp road. Figure 1- Proposed project site facing north from Highway 392 Figure 2- Proposed project site facing west from Interstate 25 DCI consulted the Natural Resources Conservation Service’s (NRCS) Web Soil Survey for a description of local soil types in the area. The natural soils encountered at the site predominantly consisted of wiley silt loam and are classified as belonging to Hydrologic Soil Group C. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 7 The site lies within the South Platte River Basin inside the Cache La Poudre River sub-basin. Inside the Cache La Poudre River sub-basin, the site is adjacent to the Fossil Creek drainage sub- basin. DCI Engineers consulted the latest FEMA Flood Insurance Rate Maps to analyze the potential floodplain delineations for the site. According to the FEMA Map 08069C1201F, the site is located in Zone X, which corresponds to an area outside of the boundary of the 500- year design storm floodplain. The DFIRM was last revised in April 2019. SECTION 2. MASTER DRAINAGE BASIN DESCRIPTION MAJOR DRAINAGE BASINS The State of Colorado is comprised of seven major river basins that are governed by separate divisions within the Colorado Department of Water Resources. The City and County of Denver make up the largest metropolitan city within the South Platte River Basin. The River Basin covers approximately 22,000 square miles in northeastern Colorado and accounts for nearly two- thirds of the state’s gross municipal and industrial water demand. Estimates of the total demand for the South Platte River Basin fall between 324,000 and 467,000 acre-feet of water per year. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 8 The South Platte Basin supports a wide range of water needs including municipal, industrial, agricultural as well as important water-dependent ecological and recreational attributes. Coloradoans and tourists regularly enjoy the recreational opportunities provided by the many environmental features of the basin. Within the South Platte River Basin, the site lies inside the Cache La Poudre River sub-basin. Inside the Cache La Poudre River sub-basin, the site is adjacent to the Fossil Creek drainage sub- basin. A Problem Identification Map was developed by the City of Fort Collins to identify the unique challenges associated within this basin. There were no problems located within the vicinity of the project site. Flood control is shown for the land in the sub-basin near the project site under the City of Fort Collins Selected Plan - Water Quality Improvements. The Fossil Creek drainage basin extends along the south end of Fort Collins, from the foothills across Interstate 25 past County Road 5. It encompasses 32 square miles in the city of Fort Collins and Larimer County. Historically, the basin consisted of agricultural land, but the basin has experienced significant development in the recent past. The original 1982 master plan mapped a floodplain and restricted developed from the floodplain; hence, fewer structures are damaged. An estimated 117 homes, 13 roads, and three railroads would be damaged during a 100-year storm with an estimated $10.6 million in damage. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 9 The existing surface conditions were considered to be entirely pervious. In the fully developed condition, we propose a weighted impervious percentage of approximately 71.6% (per the land use calculations in Appendix A), well within the defined boundaries of the previous studies for the watershed. The basin drains to the Fossil Creek Reservoir outlet under Interstate-25. As a part of this proposal, we intend to capture the onsite stormwater within underground piped structures which shall be conveyed into water quality sand filters as part of the Low Impact Design requirements and ultimately into an engineered detention pond along the western boundary of the site. Stormwater detention shall consist of surface detention per the City of Fort Collins Stormwater Criteria with discharge being limited to the 2-year historic release rate for the Fossil Creek Basin (0.2 CFS/acre). Offsite flows shall continue their existing flow-path along CDOT maintained vegetated swales along the exterior of the proposed Maverik property. After mitigating for onsite flows and accounting for offsite stormwater flows in the existing swales around the site, there is no anticipated impact to the drainageway. MINOR DRAINAGE BASINS The City of Fort Collins contains various irrigation channels designed to carry flows to different regions within the city limits. At the time of the proposed development, there are no current irrigation channels within the proposed limits of the study. Flows from the surrounding interstate off-ramp improvements are carried via vegetated surface swales to an outlet in the northwest corner of this site. The off-site flow patterns and paths will not be impacted by the proposed development on the property. The proposed Maverik site plan has been designed to allow the un-obstructed capture and conveyance of the proposed off-site flows up to the 100-year recurrence interval and bypass them safely to the existing roadside vegetated swale that was installed as part of the CDOT interchange work. Flows along this swale are conveyed towards the north into an existing culvert that travels underneath Frontage Road and into Fossil Creek. In addition, the detention basin has been designed with emergency overflows capable of discharging the fully developed 100-year un-detained flow from the 2.841-acre property. The proposed site was split into six (6) separate sub-basins delineated by general flow patterns. Roofs and canopies were treated as single basins capturing flows in an internal piped system and discharging downstream via roof downspouts. Streets and patios were separated based on anticipated slopes and drainage conditions. Flows for the entire development have been designed to slow into LID sand filters prior to reaching the detention structure. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 10 SPECIFIC BASIN DETAILS: For the purposes of drainage analysis and discussion the Maverik Convenience Store site has been analyzed using basins identifiers A though F as illustrated on the enclosed Drainage Map. Basin A is 0.11-acre located center of the site. This developed area consists of a proposed single-story building. Runoff produced within Basin A (1.1 cfs - 100-yr) is conveyed within a series of roof drains to a storm sewer manhole locate north west of the building, also known as Design Point 1. The total runoff flows to Sand Filter C where it is treated and released to the detention pond. Basin B is 0.38-acre located east and south east of the proposed building described in basin A of the site. This developed area consists of proposed asphalt drive lanes, concrete curb and gutters, concrete pavement, fuel canopy as well as new landscaping. Eighty percent of the runoff produced within Basin B (3.8 cfs - 100-yr) is collected and conveyed through proposed curb and gutter to a 5-ft wide curb inlet (Design Point 2) located near the south east corner of the building. The flows are then conveyed through a 15-inch pvc pipe to the east along the south of the building. Twenty percent of the runoff is produced from the east half of the commercial fuel canopy located south of the building and is collected in a series of roof drains where it is diverted to the same 15-inch pvc pipe from the 5-ft inlet described above. The total runoff in Basin B flows to the same Sand Filter C describe in Basin A and is treated and released to the detention pond. No impacts from runoff are anticipated to occur to the proposed structures in the 100-year event. Basin C is 0.29-acre located south and south west of the proposed building described in basin A of the site. This developed area consists of proposed asphalt drive lanes, concrete curb and gutters, concrete pavement at the trash enclosure, fuel canopy as well as new landscaping. Runoff produced within Basin C (2.9 cfs - 100-yr) is collected within the proposed curb and gutter and conveyed to a 5-ft wide curb opening, Design Point 3. Note: The commercial fuel canopy located in Basins B and C has perimeter trench drains along the east, west and north sides that are connected to the storm sewer system. These trench drains are a part of the “Fuel Spill Containment System” (FSCS) designed to capture fuel spills from under the canopies near the fuel pumps. In case of a fuel spill, the fuel will be captured by the trench drains and diverted to a spill control structure that is isolated by a shut-off valve to prevent the contaminants from reaching the sand filter (see attached exhibit in Appendix D showing the layout of the FSCS for the commercial and retail fuel canopies). A detailed description of the FSCS and Standard Operating Procedure (SOP) is also included In Appendix D of this report. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 11 Basin D is 0.40-acre located along the south end of the site. This developed area consists of proposed asphalt drive lanes and parking stalls, concrete curb and gutters, concrete pavement at the RV dumping facility, new landscaping and sand filter “B”. Runoff produced within Basin D (3.5 cfs - 100-yr) is collected within the proposed curb and gutter and conveyed to a 3-ft wide curb opening, Design Point 4. The total runoff in Basin D flows to Sand Filter B and is treated and released to the detention pond. Basin E is 1.28-acres located north of the proposed building described in basin A of the site. This developed area consists of proposed asphalt drive lanes and parking stalls, concrete curb and gutters, concrete pavement, retail fuel canopy, new landscaping and sand filter “A”. Runoff produced within Basin E (12.8 cfs - 100-yr) is collected within the proposed curb and gutter and conveyed to a 5-ft wide curb opening, Design Point 5. The flows continue through a sidewalk chase and into a concrete rundown to sand filter “A” located near the entry drive from the Frontage Road. Runoff produced from the retail fuel canopy is captured by roof drains and conveyed through a 10” storm pipe to a storm sewer manhole where it continues to flow to sand filter “C” outside Basin A to Basin F and the detention pond. Note: The retail fuel canopy located in Basins E has perimeter trench drains along the south and north sides that are connected to the storm sewer system. These trench drains are a part of the “Fuel Spill Containment System” (FSCS) for the retail fuel pumps and are designed to capture fuel spills from under the canopies near the fuel pumps. In case of a fuel spill, the fuel will be captured by the trench drains and diverted to a spill control structure that is isolated by a shut-off valve to prevent the contaminants from reaching the sand filter (see attached exhibit in Appendix D showing the layout of the FSCS for the commercial and retail fuel canopies). A detailed description of the FSCS and Standard Operating Procedure (SOP) is also included In Appendix D of this report. Basin F is 0.37-acre is located west of the proposed building and along the west property line of the site. This basin consists of proposed landscaping, concrete valley gutters, detention pond and sand filter “C”. Runoff produced within Basin F (1.3 cfs - 100-yr) is collected in the proposed valley gutter and conveyed to an outlet structure, Design Point 6. The proposed development of this site consists of an overall imperviousness of 65.1 %. SECTION 3. FLOODPLAIN INFORMATION DCI Engineers consulted the latest FEMA Flood Insurance Rate Maps to analyze the potential floodplain delineations for the site. According to the FEMA Map 08069C1201F, the site is Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 12 located in Zone X, which corresponds to an area outside of the boundary of the 500- year design storm floodplain. The DFIRM was last revised in April 2019. SECTION 4. PROJECT DESCRIPTION The subject property consists of 2.841 acres. A commercial gas station with supplementing paved parking is proposed for the subject property. The proposed 4,886 square foot convenience store facility will front SW Frontage Road and proposes approximately 31,050 sf of landscaped areas. SECTION 5. PROPOSED DRAINAGE FACILITIES A 29,002 cubic foot detention facility designed to comply with the City of Fort Collins Criteria Manual is proposed on the western boundary of the site. Grading and surface runoff shall be utilized to minimize structural BMP devices in the proposed conditions. Landscaped areas shall be utilized to assist with water quality. SECTION 6. DRAINAGE DESIGN CRITERIA FOUR STEP PROCESS TO MINIMIZE ADVERSE IMPACTS OF URBANIZATION The Mile High Flood District and the City of Fort Collins employ a four-step process to reduce the negative effects of urbanization on our existing waterways. The four steps include 1. Employing Runoff Reduction Practices 2. Implement BMPs that incorporate the water quality volume with slow release 3. Stabilizing streams 4. Implementing site specific and other source control BMPs In keeping with the requirements of the City of Fort Collins Storm Water Manual, the proposed Maverik site has been designed with ample open space that aids in the water quality treatment on the site. While large expanses of pavement are required for the standard operation of a fueling station, the proposed site plan has incorporated surface detention and surface treatment through sand filters in addition to decorative landscaping around the site. Water quality for the site is managed through a system of sand filters that have been designed to meet the criteria of the City of Fort Collins and the Mile High Flood District. Each sand filter captures the proposed water quality control volume for its tributary basin and slowly releases the volume to the downstream detention as it filters through the sand and into the underdrain system below. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 13 Due to the nature of the proposed development, site source controls will be implemented to prevent the potential effects of urbanization to the Fossil Creek Watershed. In addition to implementing Low Impact Design practices, Maverik proposes the use of fuel canopy perimeter trench drains that are connected to fuel containment vault. These trench drains and vaults are a part of the “Fuel Spill Containment System” (FSCS) designed to prevent against un-foreseen release of oil and fuel-based contaminants into the downstream waterways. . In case of a fuel spill, the fuel will be captured by the trench drains and diverted to a spill control structure that is isolated by a shut-off valve to prevent the contaminants from reaching the sand filter (see attached exhibit in Appendix D showing the layout of the FSCS for the commercial and retail fuel canopies). A detailed description of the FSCS and Standard Operating Procedure (SOP) is also included In Appendix D of this report. REGULATIONS The proposed development is located within the boundaries of the City of Fort Collins and is thus subject to the latest stormwater standards of the Fort Collins Stormwater Criteria Manual revised in December 2018. In accordance with the latest guideline, this project was analyzed with minimum and maximum release rate(s) for the developed condition 100-year recurrence interval storm. For developments smaller than 5 acres, the rational method is an accepted method for determining pre and post developed hydrology. The project’s contributing area, totaling 2.841 acres, falls into the five-acre threshold where the Modified FAA procedure is required for basin sizing. The project was analyzed using a modified FAA Rational Method in accordance with Table 6-3. The rational method is based on the direct relationship between rainfall and runoff and can be expressed by the equation. Q = CIA In which: Q = the peak rate of runoff (cubic feet per second [cfs]) C = the runoff coefficient that is the ratio between the runoff volume from an area and the average rainfall depth over a given duration for that area I = the average intensity of rainfall for a duration equal to the time of concentration (inches/hour) A = basin area (acres) Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 14 The runoff coefficients for each sub-watershed are available in the Appendix and based on Table 3.2-2. DCI Engineers has prepared a Stormwater Site Plan for review by the City of Fort Collins. It is understood that prior to the acceptance of the project, this Final Plan shall be submitted for approval by the ruling jurisdiction. Included in the Plan Review is an existing conditions map, a map of proposed development, this Final Drainage report, and an approved Soils report prepared by a geotechnical professional. Prior to the start of construction, a site Storm Water Pollution Prevention Plan (SWPPP) shall be prepared by DCI Engineers and submitted to the City of Fort Collins and the Colorado Department of Environmental Health. The Fort Collins Stormwater Criteria Manual calls for development and redevelopment projects that discharge stormwater directly, or indirectly through a conveyance system, into a surface waterbody to meet strict flow control criteria. Projects in which a total effective impervious surface is 1,000 square feet or more are required match developed discharge durations to pre- developed durations for the historic release rate of the individual drainage sub-basin. For the Fossil Creek Basin, the historic release rate is equivalent to 0.2 cfs per acre. DRAINAGE STUDIES, OUTFALL SYSTEMS PLANS, SITE CONSTRAINTS The project site has been the subject of various drainage studies and reports over the last 20 years. Maps of the Poudre River Floodplain were created for the first time in 1975. The city adopted floodplain regulations beginning in 1979. This particular site lies adjacent to the Fossil Creek drainage basin. The Master Plan for the Fort Collins drainage basins is underway at the time this report was written. A Problem Identification Map was developed by the city of Fort Collins to identify the unique challenges associated within this basin. There were no problems shown to be near the project site. Flood control is shown for the land in the sub-basin near the project site under the Selected Plan - Water Quality Improvements. The nearest “problem area” is located approximately 12,000 feet to the west along the Fossil Creek river. The proposed development associated with Maverick Fuel Station Fort Collins includes a detention basin that has been sized to handle the stormwater runoff from the 2.841-acre development. The offsite flows into the property will not flow-through the basin, but rather will be carried through a separate swale that conveys flows around the property towards the Fossil Creek Reservoir Outlet. The swales were constructed and maintained by CDOT as part of the 2011 I-25 and Highway 392 Interchange Project. HYDROLOGY The project’s contributing area, totaling 2.84-acres, contains multiple sub-basins that are under Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 15 the five-acre threshold for the use of the Rational Method: The rational method is based on the direct relationship between rainfall and runoff and can be expressed by the equation Q = CIA In which: Q = the maximum rate of runoff (cubic feet per second [cfs]) C = the runoff coefficient that is the ratio between the runoff volume from an area and the average rainfall depth over a given duration for that area I = the average intensity of rainfall for a duration equal to the time of concentration (inches/hour) A = basin area (acres) Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 16 Table 3.2-2. Surface Type - Runoff Coefficients Surface Type Runoff Coefficients Hardscape or Hard Surface Asphalt, Concrete 0.95 Rooftop 0.95 Recycled Asphalt 0.8 Gravel 0.5 Pavers 0.5 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope < 2% 0.1 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.2 Lawns, Clayey Soil, Flat Slope < 2% 0.2 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 0.35 Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 17 IDF curves for Rational Method Duration (min) Intensity 2- year (in/hr) Intensity 100- year (in/hr) 5.00 2.85 9.95 10.00 2.21 7.72 15.00 1.87 6.52 20.00 1.61 5.60 25.00 1.43 4.98 30.00 1.30 4.52 35.00 1.17 4.08 40.00 1.07 3.74 45.00 0.99 3.46 50.00 0.92 3.23 55.00 0.87 3.03 60.00 0.82 2.86 65.00 0.78 2.71 70.00 0.73 2.59 75.00 0.70 2.48 80.00 0.66 2.38 85.00 0.64 2.29 90.00 0.61 2.21 95.00 0.58 2.13 100.00 0.56 2.06 105.00 0.54 2.00 110.00 0.52 1.94 115.00 0.51 1.88 120.00 0.49 1.84 Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 18 The basis of storm drainage and hydrologic design for the City of Fort Collins is found in Chapters 5 and 6 of the Fort Collins Stormwater Criteria Manual. An analysis of the Isopluvial Maps show that all areas within the Fort Collins area can be described within a single rainfall zone with minimal variation. The 1-hour duration rainfall depth for various recurrence intervals has historically been used for the calculation of runoff using the Rational method. For the purpose of small urban watersheds less than 20 acres in size, a rainfall intensity duration frequency curve can be used in association with the Rational Method, to determine rainfall intensity distribution over the period of the 1 hour duration equation 5.1 from the SDDTC describes the intensity with the following equation: Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 19 DETENTION STORAGE CALCULATION New development and significant redevelopment in the City of Fort Collins is governed by the Fort Collins Stormwater Criteria Manual. Per the Fort Collins Stormwater Criteria Manual, the Modified FAA Procedure was utilized to size the detention volume. The peak control volume for the 100 year was determined, while maintaining release rates at the historic 2 year release for the Fossil Creek Basin. The City of Fort Collins utilizes the criteria described in the Storm Drainage Design and Technical Criteria as well as the District Manual to determine infiltration potential as it relates to soil types. In general, hydrologic soils group are classified into four categories based on ability to infiltrate stormwater. Hydrologic Group A has the highest capacity for infiltration, Hydrologic Group B is considered moderate, while Groups C and D are considered poor drainage and generally unsuitable for infiltration. An investigation of soils groups through the National Resource Conservation Service (NRCS) for our site indicates that the majority of soils within the project area can be classified as Hydrologic Group C based on the results of an NRCS Web Soil Survey analysis. Storm drainage runoff shall be determined by the Rational Method because the site is less than 5 acres. Table 2.0-1 below summarizes the acceptable methods along with an established criterion for the use of each method. The drainage system shall account for runoff from both minor and major storm events as required in Section 1.4 of the FCSWCM. The design capacity for the development for the major and minor storm events does not include the effects of onsite detention on the peak flows. In all cases, the onsite system has been designed to minimize life hazards and health, damage to structures, and interruption to traffic and services associated with the 100-year storm event. The City of Fort Collins maintains a policy requirement for onsite detention of flood flows for all development and redevelopment projects as defined in the Fort Collins Stormwater Criteria Manual (FCSCM). Onsite detention is required or all projects proposing 1,000 sf of impervious coverage or more. Storage for the onsite detention of runoff shall be governed by the policies set forth in Chapter 6 of the Criteria Manual. The City of Fort Collins requires the Modified FAA Procedure for water quality detention design for sites less than 5 acres. The Modified FAA Procedure determines volumetric storage for peak flows. The FCSCM requires a peak release rate for the 100-year storm for the post developed condition to be no greater than the 2-year historic release rate of 0.2 cfs per acre. The project will utilize a modified version of the City of Fort Collins Water Quality Outlet Structure standard detail D-46. Because water quality is being Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 20 provided upstream of the detention pond via Sand Filters, the outlet structure has been modified to provide the 100-year orifice plate in the location where the Water Quality Orifice would typically be installed. The 100-year orifice plate has been sized to meter the release rate from the pond during the 100-year storm event to comply with the allowable release rate of 0.57 cfs. The top of the outlet structure is set at the 100-year water surface elevation. During storm events that exceed the 100-year recurrence interval (4881.90), water will overtop the outlet structure which is also equal to the 100 yr WSE and discharge through the 12-inch outlet pipe. The outlet structure outlet pipe can convey 2.66 cfs. Any flows exceeding the outlet pipe’s capacity will overtop the emergency spillway at an elevation of 4882.00. In order to detain the difference between the post-developed 100-year flow rate and the historic 2-year flows, the detention pond must hold a required 28,346 cf of runoff with a metered outflow to Fossil Creek. The provided pond volume is 29,002 cf. The detention pond calculations can be found in Appendix A. HYDRAULICS In accordance with the City of Fort Collins standards, drainage for the proposed Maverik Fuel Station has been designed to adequately capture and convey the runoff form the site for both the major and minor storm event. Pipes, swales, and catch basins have been designed to handle the 2-year developed flow rate as well as the 100-year major storm event based on a rational method analysis of each sub-drainage basin. We have assumed a frost depth of 30” from finished surface. HYDRAULIC GRADE LINE CALCULATION METHOD Private storm drainage for the property has been designed using the hydraulic grade line calculation and the methods outlined below. For the purposes of design, Manning’s equation was used to calculate the available pipe capacity at full flow for a stretch of pipe. Manning’s Equation is shown below: Q = (1.49/n) AR 2/3 S ½ Where Q = available flow rate (cfs) n = Manning’s roughness factor A = cross sectional flow area (sf) R = hydraulic radius = D/4 (ft) S = friction slope (ft/ft) In order to analyze the hydraulic capacity of the onsite storm drain system, head losses were calculated through the pipe network to determine the Energy Grade Line. Head losses through pipe networks are defined by the following equation H = KoCDCdCQCPCB (V2/2g) Where K = initial loss coefficient Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 21 V = velocity in the outflow pipe g = gravitational acceleration (32.2 ft/sec2) C = correction factors for pipe size, bends, etc. WATER QUALITY ENHANCEMENT Per the current requirements of the Fort Collins Stormwater Manual, all new or redevelopment projects are required to implement Low Impact Development design as part of the initial site concept. The land Use Code allows for adherence to the L.I.D. requirements by one of the following options: 1. 50% of the newly added or modified impervious areas must be treated by LID techniques and 25% of new paved areas must be pervious 2. 75% of all newly added or modified impervious areas must be treated by LID techniques. Due to the soil conditions on this site, the use of pervious pavements is not recommended. As a result, Maverik proposed compliance with the Low Impact Development requirement using Option 2. The site proposes the use of L.I.D. sand filters to treat 100% of new impervious areas on the site. Sand Filters were designed in accordance with Chapter 7 of the FCSM as well as the Low Impact Development Implementation Manual (July 2017). Best Management Practices were designed to capture and treat the Water Quality Capture Volume as specified in the equation below WQCV = a (0.913 – 1.19I2 + 0.78I ) WQCV = Water Quality Control Volume (in watershed inches) A = Coefficient corresponding to WQCV drain time [Table 5.4.-1] I = Imperviousness (%/100) From FCSCM Table 5.4-1: Drain Time Coefficients for WQCV Calculations The required BMP Storage Volume, V is computed using Equation 7-2: V = (WQCV / 12 ) x A x 1.2 V = required volume, acre-ft Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 22 A = tributary catchment area upstream, acres WQCV = Water Quality Capture Volume, watershed inches 1.2 = to account for the additional 20% of required storage for sedimentation accumulation DCI proposes the use of engineered sand filters to capture and remove pollutants from the asphalt and concrete roadways prior to conveyance into the detention pond. The sand filter consists of a surcharge zone underlain by a sand bed with a perforated pipe underdrain system. A forebay consisting of 1% of the WQCV shall be implemented at each sand filter. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 23 Three sand filters are proposed on the site. Sand Filter A, which is designed to treat flows coming from the passenger vehicle fueling court treats 1.29 acres of tributary area for a total volume of 1,916 cubic feet. Sand Filter B corresponds to a tributary area of 0.49 acres which captures flows from a large portion of the commercial fueling court on the south side of the building. Lastly, flows from the building roofs, canopies, and the northern portion of the commercial fueling court are conveyed into a curb inlet to a designed sand filter located just west of the proposed structure. Sand Filter C has been designed to capture the water quality flows from 0.8 acres of tributary area for a total volume of 1,394 cubic feet. Immediately underneath the fueling canopies, Maverik proposes the use of an underground storage chamber system designed to capture potential spills or leaks of fuel or oil-contaminated water prior to entering the storm drain system. The sill containment chambers will capture potential contaminants and treat them through an oil/water separator prior to discharge into the downstream detention system. An LID Site Plan has been included in the appendices. EROSION CONTROL Maverik, Inc. is dedicated to the preservation of the natural environment throughout the life cycle of the project. The project shall maintain compliance with all requirements of the City of Fort Collins Erosion Control Criteria, including the provisions of Chapters 3 and 4 of the Stormwater Manual. An Erosion and Sediment Control Plan (along with associated details) is included with the final construction drawings. Staging and/or phasing of the BMPs depicted, and additional or different BMPs from those included may be necessary during construction, or as required by the authorities having jurisdiction. It shall be the responsibility of the Contractor to ensure erosion control measures are properly maintained and followed. The Erosion and Sediment Control Plan is intended to be a active Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 24 document, continually acclimating to site conditions and needs. The Contractor is also responsible for updating BMPs as dictated throughout construction. The Erosion and Sediment Control Plan will demonstrate the use of both temporary measures and permanent erosion control protection during and upon completion of construction activities. BMP’s from the MHFD and the City of Fort Collins Erosion Control Reference Manual for Construction Sites will be utilized. Expected measures include silt fencing along the disturbed perimeter, gutter protection in the adjacent roadway, and inlet protection at proposed storm inlets and culverts. Vehicle tracking control pad, spill containment and clean-up procedures, designated concrete washout areas, and job site restrooms shall also be provided by the Contractor. SECTION 7: CONCLUSIONS The Final Drainage Report for Maverik Fort Collins has been designed to comply with the requirements of the City of Fort Collins Stormwater Criteria Manual. The drainage has been analyzed using the Rational Method for the minor and major storm events. Through the use of an engineered detention pond, the site shall detain the difference between the 100-year developed flow rate and the 2-year historic flow rate for the Fossil Creek Basin. In addition, 100% of the site impervious area shall be treated for water quality utilizing Low Impact Development in accordance with the LID Implementation Manual. SECTION 8: APPENDICES Please refer to the attached Appendices for additional information/ reference documents. SECTION A: HYDROLOGIC COMPUTATIONS and HYDRAULIC SIZING SECTION B: WATER QUALITY /LID COMPUTATIONS SECTION C: REFERENCE INFORMATION SECTION D: SPILL CONTAINMENT SYSTEM STANDARD OPERATING PROCEDURE SDSSSSWWWWWWW W W WWW W W W W W W SSSSSSSS SS SS SS SS 2.03 7.06 H-1 2.84 5 PRE-DEVELOPED DRAINAGE CONDITIONS 1 A 1.41 A 0.14 0.40 1 PROJECT NUMBER ISSUE DATE: REVISIONS:MAVERIK INC. STOREI-25 & E. COUNTY RD. 32 / HIGHWAY 392FORT COLLINS, CONo. Date Description NOTE: Conflicting information or errors found inthe construction documents should bebrought to the attention of the architectimmediatly. In the event of a conflict in thedrawings, bidder should not assume theleast expensive option will meet theproject requirements. Bid documents should not be separatedor issued as partial sets tosubcontractors. Bidders are responsiblefor all portions of the documents thatpertain to work covered by sub-bids.Bidder assumes full responsibility forerror or misinterpretations resultingfrom partial sets of Bidding Documentsby itself or any sub-bidder.2021-07-27Plot Date: File Location:O:\1200-Denver\DCI-Civil\Projects\2019\19-122-0006-MAVERIK-FORT COLLINS-CO\19-122-0006FDP.dwg OF 1331 17TH STREET SUITE 605DENVER, COLORADO 80202PHONE: (720) 439-4700 WEBSITE: www.dci-engineers.com CIVIL / STRUCTURAL 07/2021© This document, and the ideas and designs may not be reused, in whole orin part, without written permission from D'Amato Conversano Inc.D'Amato Conversano Inc. disclaims any responsibility for its unauthorized use. JULY 28, 2021 19-122-0006 3 VANSTOP STOP SDSSSSSSWWWWWWW W W WWW W W W W W W SSSSSSSS SS SS SS SS SS W 5 2 3 4 6 1 0.790.98 E 1.28 0.770.97 B 0.38 0.951.00 A 0.11 0.700.88 D 0.40 0.92 1.00 C 0.30 0.25 0.31 F 0.35 1 0.400.14 A 1.41 A POST-DEVELOPED DRAINAGE CONDITIONS 2 PROJECT NUMBER ISSUE DATE: REVISIONS:MAVERIK INC. STOREI-25 & E. COUNTY RD. 32 / HIGHWAY 392FORT COLLINS, CONo. Date Description NOTE: Conflicting information or errors found inthe construction documents should bebrought to the attention of the architectimmediatly. In the event of a conflict in thedrawings, bidder should not assume theleast expensive option will meet theproject requirements. Bid documents should not be separatedor issued as partial sets tosubcontractors. Bidders are responsiblefor all portions of the documents thatpertain to work covered by sub-bids.Bidder assumes full responsibility forerror or misinterpretations resultingfrom partial sets of Bidding Documentsby itself or any sub-bidder.2021-07-27Plot Date: File Location:O:\1200-Denver\DCI-Civil\Projects\2019\19-122-0006-MAVERIK-FORT COLLINS-CO\19-122-0006FDP.dwg OF 1331 17TH STREET SUITE 605DENVER, COLORADO 80202PHONE: (720) 439-4700 WEBSITE: www.dci-engineers.com CIVIL / STRUCTURAL 07/2021© This document, and the ideas and designs may not be reused, in whole orin part, without written permission from D'Amato Conversano Inc.D'Amato Conversano Inc. disclaims any responsibility for its unauthorized use. JULY 28, 2021 19-122-0006 3 Elevation Area (sqft) Volume Between Contours (cf) Total Volume (cf) Bottom 4878.00 2553 - 4330.41 4879.00 6397 4,330 7248.13 4880.00 8134 11,579 8671.82 4881.00 9221 20,250 8751.23 100-yr WSE 4881.90 10235 29,002 11964.76 Spillway 4882.00 10350 40,966 10935.68 Top 4883.00 11532 40,966 Total Volume (cf) 40,966 AVAILABLE SITE DETENTION POND VOLUME Required Volume = 28,346 CF Pond Characteristics A=Area of bottom contour, (sf) B=Area of top contour, (sf) 100-yr W.S. EL. = 4881.90 (Volume = 29,002 CF) V = D/3(A+B+(A*B)^1/2 WHERE: V=Volume between contours, (cf) D=Depth between contours, (ft) Pipe Naming for Hydraulic Sizing VANSTOP STOP SDSSSSWWWWWWW W W WW W W W W W W SSSSSS SS SS SS SS W LID SITE PLAN 3 PROJECT NUMBER ISSUE DATE: REVISIONS:MAVERIK INC. STOREI-25 & E. COUNTY RD. 32 / HIGHWAY 392FORT COLLINS, CONo. Date Description NOTE: Conflicting information or errors found inthe construction documents should bebrought to the attention of the architectimmediatly. In the event of a conflict in thedrawings, bidder should not assume theleast expensive option will meet theproject requirements. Bid documents should not be separatedor issued as partial sets tosubcontractors. Bidders are responsiblefor all portions of the documents thatpertain to work covered by sub-bids.Bidder assumes full responsibility forerror or misinterpretations resultingfrom partial sets of Bidding Documentsby itself or any sub-bidder.2021-07-27Plot Date: File Location:O:\1200-Denver\DCI-Civil\Projects\2019\19-122-0006-MAVERIK-FORT COLLINS-CO\19-122-0006FDP.dwg OF 1331 17TH STREET SUITE 605DENVER, COLORADO 80202PHONE: (720) 439-4700 WEBSITE: www.dci-engineers.com CIVIL / STRUCTURAL 07/2021© This document, and the ideas and designs may not be reused, in whole orin part, without written permission from D'Amato Conversano Inc.D'Amato Conversano Inc. disclaims any responsibility for its unauthorized use. JULY 28, 2021 19-122-0006 3 Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =84.9 % (100% if all paved and roofed areas upstream of sand filter) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.849 C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.29 watershed inches WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including sand filter area)Area = 49,419 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =1,191 cu ft VWQCV = WQCV / 12 * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth DWQCV =1.0 ft B) Sand Filter Side Slopes (Horizontal distance per unit vertical, Z = 4.00 ft / ft 4:1 or flatter preferred). Use "0" if sand filter has vertical walls. C) Minimum Filter Area (Flat Surface Area)AMin =524 sq ft D) Actual Filter Area AActual =1687 sq ft E) Volume Provided VT =2491 cu ft 3. Filter Material 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =cu ft iii) Orifice Diameter, 3/8" Minimum DO = in 19122-0006 Maverick Fort Collins, Colorado - Sand Filter "A" Design Procedure Form: Sand Filter (SF) Shawn Krieger DCI Engineers July 27, 2021 UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" CDOT Class B or C Filter Material Other (Explain): YES NO UD-BMP_v3.07_SF-A.xlsm, SF 7/27/2021, 2:50 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Works A) Describe the type of energy dissipation at inlet points and means of conveying flows in excess of the WQCV through the outlet Notes: Design Procedure Form: Sand Filter (SF) Shawn Krieger DCI Engineers July 27, 2021 19122-0006 Maverick Fort Collins, Colorado - Sand Filter "A" Choose One YES NO UD-BMP_v3.07_SF-A.xlsm, SF 7/27/2021, 2:50 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =60.7 % (100% if all paved and roofed areas upstream of sand filter) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.607 C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.19 watershed inches WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including sand filter area)Area = 17,520 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =279 cu ft VWQCV = WQCV / 12 * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth DWQCV =1.0 ft B) Sand Filter Side Slopes (Horizontal distance per unit vertical, Z = 4.00 ft / ft 4:1 or flatter preferred). Use "0" if sand filter has vertical walls. C) Minimum Filter Area (Flat Surface Area)AMin =133 sq ft D) Actual Filter Area AActual =968 sq ft E) Volume Provided VT =1593 cu ft 3. Filter Material 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =cu ft iii) Orifice Diameter, 3/8" Minimum DO = in 19122-0006 Maverick Fort Collins, Colorado - Sand Filter "B" Design Procedure Form: Sand Filter (SF) Shawn Krieger DCI Engineers July 27, 2021 UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" CDOT Class B or C Filter Material Other (Explain): YES NO UD-BMP_v3.07_SF-B.xlsm, SF 7/27/2021, 2:49 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Works A) Describe the type of energy dissipation at inlet points and means of conveying flows in excess of the WQCV through the outlet Notes: Design Procedure Form: Sand Filter (SF) Shawn Krieger DCI Engineers July 27, 2021 19122-0006 Maverick Fort Collins, Colorado - Sand Filter "B" Choose One YES NO UD-BMP_v3.07_SF-B.xlsm, SF 7/27/2021, 2:49 PM Sheet 1 of 2 Designer: Company: Date: Project: Location: 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, Ia Ia =89.1 % (100% if all paved and roofed areas upstream of sand filter) B) Tributary Area's Imperviousness Ratio (i = Ia/100)i = 0.891 C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.32 watershed inches WQCV= 0.8 * (0.91* i3 - 1.19 * i2 + 0.78 * i) D) Contributing Watershed Area (including sand filter area)Area = 40,510 sq ft E) Water Quality Capture Volume (WQCV) Design Volume VWQCV =1,064 cu ft VWQCV = WQCV / 12 * Area F) For Watersheds Outside of the Denver Region, Depth of d6 = in Average Runoff Producing Storm G) For Watersheds Outside of the Denver Region, VWQCV OTHER =cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume VWQCV USER =cu ft (Only if a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth DWQCV =1.5 ft B) Sand Filter Side Slopes (Horizontal distance per unit vertical, Z = 4.00 ft / ft 4:1 or flatter preferred). Use "0" if sand filter has vertical walls. C) Minimum Filter Area (Flat Surface Area)AMin =451 sq ft D) Actual Filter Area AActual =651 sq ft E) Volume Provided VT =1626 cu ft 3. Filter Material 4. Underdrain System A) Are underdrains provided?1 B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y =ft Volume to the Center of the Orifice ii) Volume to Drain in 12 Hours Vol12 =cu ft iii) Orifice Diameter, 3/8" Minimum DO = in 19122-0006 Maverick Fort Collins, Colorado - Sand Filter "C" Design Procedure Form: Sand Filter (SF) Shawn Krieger DCI Engineers July 27, 2021 UD-BMP (Version 3.07, March 2018) Choose One Choose One 18" CDOT Class B or C Filter Material Other (Explain): YES NO UD-BMP_v3.07_SF-C.xlsm, SF 7/27/2021, 2:51 PM Sheet 2 of 2 Designer: Company: Date: Project: Location: 5. Impermeable Geomembrane Liner and Geotextile Separator Fabric A) Is an impermeable liner provided due to proximity of structures or groundwater contamination? 6. Inlet / Outlet Works A) Describe the type of energy dissipation at inlet points and means of conveying flows in excess of the WQCV through the outlet Notes: Design Procedure Form: Sand Filter (SF) Shawn Krieger DCI Engineers July 27, 2021 19122-0006 Maverick Fort Collins, Colorado - Sand Filter "C" Choose One YES NO UD-BMP_v3.07_SF-C.xlsm, SF 7/27/2021, 2:51 PM Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 1 Fuel Spill Containment System and Standard Operating Procedure (SOP) for Maverik Inc. Store I-25 & North County Road 32 (Hwy 392) Fort Collins, Colorado 80528 Background A Fuel Spill Containment System (FSCS) consists of trench drains with grates installed at the surface surrounding fuel canopies. The trench drains collect any fuel spillage that may occur at the fuel pumps. The trench drains connect to a Fuel Spill Containment Vault designed to contain a minimum of 150 gallons of spilled fuel. The Vault is also designed to allow any normal drainage to flow through to the outfall of the system. Fuel spills are isolated by closing a gate valve located 2 feet downstream from the vault (see attached exhibit for location of gate valves). The fuel is then promptly removed through an access hatch / manhole installed in the top of the Vault. The Vault is connected to the upstream trench drains and downstream outfall with 6” PVC pipe. The entire system is gravity fed and is constructed to ensure positive drainage throughout the system to the outfall. Normal Function of Fuel Spill Containment System Whether there is a fuel spill or not, the trench drains will capture any upstream runoff that normally occurs. The valve 2 feet downstream of the Fuel Spill Containment Vault should be left open under normal conditions to allow runoff to pass through to the downstream stormwater system. This runoff will flow through the system whether there is a fuel spill contained in the Vault or not and will be released at the outfall. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 2 Standard Operating Procedure (SOP) - Actions to be Taken After a Fuel Spill Incident In the event of a fuel spill, the following shall be the basic course of action:  Shut down equipment  Evacuate the area  Block access to the area  Close valve just downstream of Fuel Spill Containment Vault  Contact designated emergency personnel  Determine the source of the spill  Stop the spill at the source  Apply absorbent to soak up spilled fuel  Use neutralizing agents to reduce the chance of fuel ignition  Sweep up absorbent and neutralizing agents and dispose of properly  Safely remove and properly dispose of spilled fuel detained within the Fuel Spill Containment Vault to prevent discharge to either storm or sanitary sewer  Use absorbent pads to soak up any remaining fuel and chemicals  Dispose of used absorbent pads in designated barrels  Completely clean containment system and collect the wash water and dispose properly  Check the outfall for spill that may have escaped the Fuel Spill Containment Vault and clean up area if necessary  Once the fuel spill is cleaned up completely open the valve just downstream of Fuel Spill Containment Vault to allow runoff to flow through normally The action procedure presented above is meant to be a guideline for what to do to clean up a fuel spill that has been contained within a FSCS. It is the responsibility of the owner/operator to have a detailed hazardous material spill procedure and all materials and equipment on hand to implement it. Other procedures and actions may be required by local, state, and federal regulations such as reporting and investigating the incident. All required procedures should be followed in an incident where fuel is spilled. Final Drainage Report: Maverik Fuel Station Fort Collins DCI Engineers July 28, 2021 3 Fuel Spill Containment System Required Action Maintenance Objective Frequency of Action Trench Drain Inspection Inspect the trench drain through the grates and from each end. Look for obstructions, vegetation, debris, litter, sediment, etc. inside the trench drain. Vegetation or algae growing in the trench drain indicate the presence of standing water. Water backing up out of the trench drain entrance indicates a blockage. During a rainstorm, a blockage will be indicated by slow water flow or by water backing up at the trench drain entrance. Routine - Including just before annual storm seasons (that is, April and May), end of storm season after leaves have fallen, and following significant rainfall events. Trench Drain Sediment Debris and Litter removal Clear as much of the trench drain as possible from each end with a long- handled tool such as a hoe. Raise the grates to clean inaccessible portions of the trench drain. Scrape with hoe or similar tool to ensure that water flows freely along the concrete flow-line of the trench drain Routine - Including just before annual storm seasons (that is, April and May), end of storm season after leaves have fallen, and following significant rainfall events. Fuel Spill Containment Vault inspection lnspect vault to ensure that the vault continues to function as initially intended. Examine the outlet for clogging, excessive sedimentation levels, oily sheen, and damage to any structural element. Routine - Annual inspection of hydraulic and structural facilities. Also check for obvious problems during routine maintenance visits, especially for plugging of outlets. Fuel Spill Containment Vault Sediment Oily Sheen, Debris, and Litter removal Vacuum and remove accumulated sediment and liquids from the bottom of the vault through the access hatch on the top of the vault. Ensure outlet is clear of debris. Routine - Annually including just before annual storm seasons (that is, April and May), end of storm season after leaves have fallen, and following significant rainfall events and when oily sheen is seen during any routing inspection. VAN2600 Michelson Drive, SUITE 930Irvine, Ca 92612PHONE: (949) 892-4950WEBSITE: www.dci-engineers.com CIVIL / STRUCTURAL COMMERCIAL FUEL CANOPY RESIDENTIAL FUEL CANOPY FUEL SPILL CONTAINMENT VAULT WITH ACCESS MANHOLE FUEL SPILL ISOLATION VALVE IN VALVE BOX. USE HANDWHEEL TO OPEN AND CLOSE VALVE PERIMETER TRENCH DRAINS PERIMETER TRENCH DRAINS FUEL SPILL CONTAINMENT VAULT WITH ACCESS MANHOLE FUEL SPILL ISOLATION VALVE IN VALVE BOX. USE HANDWHEEL TO OPEN AND CLOSE VALVE