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engineering CIVAS civil engineering solutions 10056 Brisbane Lane Littleton Colorado 80130 [PHONE REDACTED] civas−eng.com MONUMENT MARKETPLACE NORTH, FILING NO. 1A, LOT 4A MONUMENT, COLORADO FINAL DRAINAGE REPORT Prepared for: MAH Architectural Group 1385 S Colorado Blvd., Penthouse Denver, Colorado 80222 phone: (303) 778-0608 Prepared by: CIVAS Engineering, LLC 10056 Brisbane Lane Littleton, Colorado 80130 phone: (720) 240-5882 November 7, 2023 Project No. 23-315 ---PAGE BREAK--- 1 I. ENGINEER’S STATEMENT: The attached drainage plan and report were prepared under my direction and supervision and are correct to the best of my knowledge and belief. Said drainage report has been prepared according to the criteria established by the City/County for drainage reports and said report is in conformity with the master plan of the drainage basin. I accept responsibility for any liability caused by any negligent acts, errors, or omissions on my part in preparing this report. Steven M. Strickling, P.E. Colorado Number 31237 For and On Behalf of CIVAS Engineering, LLC II. DEVELOPER’S STATEMENT: I, the developer, have read and will comply with all of the requirements specified in this drainage report and plan. . [Name], [Title] Date [Company Name] [Address] III. TOWN OF MONUMENT: Filed in accordance with Section 17.45 of the Zoning Ordinance for the Town of Monument and Section 16.12.060 of the Subdivision Code for the Town of Monument, revised February 2007. Director of Development Services Date ---PAGE BREAK--- 2 INTRODUCTION This report represents a Final Drainage Report for Monument Marketplace North, Filing No. 1A, Lot 4A, and was prepared in accordance the El Paso County Drainage Criteria Manual (DCM) and satisfies the Town of Monument submittal requirements. This report was also prepared using portions of the City of Colorado Springs DCM, latest editions. This report addresses post-development storm peak runoff rates for the 5-year and 100-year storm events. Stormwater detention and water quality is provided for the project by an existing regional facility located west of the subject property on the west side of Cinematic Drive. PROPERTY LOCATION AND DESCRIPTION Lot 4A, Monument Marketplace Filing No. 1A is part of the Monument Marketplace North PD Site Plan, a which is an 11.84 ac. planned business/commercial development located west of Jackson Creek Parkway, north of the Monument Marketplace and east of !-25 in the Town of Monument, Colorado. The planned use for Lot 4A is for a Ziggi’s Coffee restaurant with associated parking, sidewalk, utility and landscape improvements. The property is surrounded by existing platted, undeveloped commercial lots to the south west and north and Jackson Creek Parkway, a public right-of-way to the east. Access to the site is from a proposed driveway cut in Cinematic View, a private road located within a 40’ wide access easement, 20’ of which is located on the west side of Lot 4A. ---PAGE BREAK--- 3 FIGURE 1 - VICINITY MAP Soil on the majority of the site, as classified by the Soil Conservation Services of the U.S. Department of Agriculture in the Soil Survey for the El Paso County Area (refer to figures 2, 3 and is Pring coarse sandy loam (71). This soil type has a slow runoff rate and a rapid permeability rate. Pring coarse sandy loam (71) is part of hydrologic soil group B (refer to figure ---PAGE BREAK--- 4 FIGURE 2 – SCS SOIL SURVEY MAP ---PAGE BREAK--- 5 FIGURE 3 – SCS SOIL SURVEY MAP LEGEND FIGURE 4 – SCS SOIL SURVEY SOIL MAP UNITS ---PAGE BREAK--- 6 FIGURE 5 – SCS SOIL SURVEY HYDROLOGIC SOIL GROUP DRAINAGE CRITERIA The El Paso County Drainage Criteria Manual (DCM) and the City of Colorado Springs DCM latest editions were used in the preparation of this report. The Rational Method was used to calculate the post-development storm peak flows for the 5-year and 100- year storm events FLOODPLAIN IMPACTS The FEMA Flood Insurance Rate Map (FIRM) firmette for Community Panel 08041C0278G, revised December 7, 2018 (refer to figure 6) shows that no portion of this development lies within the 100·year flood plain of Teachout Creek, nor its tributaries. ---PAGE BREAK--- 7 FIGURE 6 – FIRM FIRMETTE FOR COMMUNITY PANEL 08041C0278G EXISTING DRAINAGE BASINS The project site is located in Drainage Basin A2 (0.7 ac.) and Drainage Basin A4 (2.0 ac.) as shown on the Drainage Map Developed Conditions for Monument Marketplace North Filing No. 1, within the Final Drainage Report for Monument Marketplace North Filing No. 1, a copy of which is located in the appendix of this report. Drainage Basin A2 sheet flows to the southwest to 5’ and 10’ at grade curb inlets located at Design Point 2 which is on the west side of Cinematic View, a private road. Drainage Basin A4 surface flows onto the northwest portion of the adjacent lot to the south, Lot 5 and ultimately to a 10’ sump curb inlet at Design Point 4 which is located on the west side of Cinematic View. RCP storm sewer systems convey developed flows from the inlets ---PAGE BREAK--- 8 to a Water Quality and Detention Pond on the west side of Cinematic View located southwest of the project site. The storm sewer system and the water quality and detention pond have recently been constructed per the Monument Marketplace North construction plans. DEVELOPED DRAINAGE BASINS The proposed Monument Marketplace North, Filing No. 1A, Lot 4A development, also known as Ziggi’s Coffee, has been divided into 2 drainage basins, A2a and A4a. Developed runoff from basin A2a surface flows across the pavement to concrete pans and catch curb and gutter and surface flows across Cinematic View to existing curb and gutter which conveys developed flows to the south to the existing 5’ and 10’ at grade curb inlets, as previously discussed in the Existing Drainage Basins section of this report. Developed runoff from drainage basin A4a sheet flows across the landscape, sidewalk and pavement areas to catch curb which conveys flows to rip rap aprons located at the low point of the basins. A landscape swale will convey flows to a concrete apron and sidewalk chase in the adjacent development on Lot 5. The flows will surface flow across the parking lot of that development to south and southwest and across Cinematic View to existing catch curb and gutter which conveys flows to the south to the existing 10’ sump curb inlet, previously discussed in the Existing Drainage Basins section of this report. The drainage basin characteristics and developed flows are listed in the Design Point Summary Table below. ---PAGE BREAK--- 9 WATER QUALITY The four step process has been taken to select and implement stormwater quality control measures for the Monument Marketplace North, Filing No. 1A, Lot 4A development, also known as Ziggi;s Coffee, in accordance with Section I.7.2 of the El Paso County Engineering Criteria Manual. Step 1: Employ Runoff Reduction Practices. The existing topography, the existing storm drainage facilities and the proposed site layout for the Monument Marketplace North, Filing No. 1A, Lot 4A development, also known as Ziggi;s Coffee, does not make it feasible to minimize the directly connected impervious areas (DCIA) by creating receiving porous areas (RPA) that would receive runoff from unconnected impervious areas (UIA). Step 2: Stabilize Drainageways. There are no existing streams or drainageways on this site. Therefore no stabilization is required. Step 3: Provide Water Quality Capture Volume (WQCV). Water quality capture volume is provided for the proposed project in the existing regional Water Quality and Detention Pond for the Monument Marketplace North Filing No. 1 development, also known as Ziggi’s Coffee. Step 4: Consider Need for Industrial and Commercial BMPs. The Monument Marketplace North, Filing No. 1A, Lot 4A development, also known as Ziggi’s Coffee, will provide source control Best Management Practices (BMP’s) that include periodic sweeping of the parking lot to prevent accumulation of litter and debris, periodic inspection of the outdoor trash receptacle and enclosure to ensure that the lid and enclosure gate are functioning so that the trash is properly covered and contained, the collection and disposal of grass clippings after mowing operations and maintaining the landscaping with a minimal use of pesticides and fertilizers. ---PAGE BREAK--- 10 Design flows from the proposed Monument Marketplace North, Filing No. 1A, Lot 4A (MMN Flg 1 L 4A) development, also known as Ziggi’s Coffee, are in compliance with the design flows calculated in the Final Drainage Report for Monument Marketplace North Filing No. 1 (MMN Flg 1) as summarized below. Ziggi’s Coffee MMN Flg 1 L 4A MMN Flg 1 Basin Area (ac.) Q5/Q100 (cfs) Basin Area (ac.) Q5/Q100 (cfs) A2a 0.63 1.8 / 3.6 A2* 0.63 2.7 / 4.5 A4a 0.26 0.6 / 1.3 A4* 0.26 1.0 / 2.0 *Basin A2 per MMN Flg 1 is 0.7 ac. and Q5 = 3.0 cfs and Q100 = 5.0 cfs. The ratio of Lot 4A within Basin A2 = 0.63/0.7 = 0.90. The prorated runoff from Lot 4A within Basin A2 is Q5 = 0.90 x 3.0 cfs = 2.7 cfs and Q100 = 0.90 x 5.0 cfs = 4.5 cfs. *Basin A4 per MMN Flg 1 is 2.0 ac. and Q5 = 8.0 cfs and Q100 = 15.0 cfs. The ratio of Lot 4A within Basin A4 = 0.26/2.0 = 0.13. The prorated runoff from Lot 4A within Basin A4 is Q5 = 0.13 x 8.0 cfs = 1.0 cfs and Q100 = 0.13 x 15.0 cfs = 2.0 cfs. CONCLUSIONS A. Compliance with Standards This report has been prepared in accordance with the El Paso County Drainage Criteria Manual. The drainage improvements provide adequate protection to this site without adverse impacts on adjoining upstream or properties and are in compliance with the Final Drainage Report for Monument Marketplace North Filing No. 1. ---PAGE BREAK--- 11 B. Drainage Concept The proposed drainage patterns and drainage design for the Monument Marketplace North, Filing No. 1A, Lot 4A development, also known as Ziggi’s Coffee conform to the approved Drainage Map Developed Conditions for Monument Marketplace North Filing No. 1, within the Final Drainage Report for Monument Marketplace North Filing No. 1. Developed runoff from this development will be conveyed by an existing public drainage system to an existing regional water quality and detention pond located on the west side of Cinematic View, southwest of the proposed development, which releases flows at historic rates, mitigating the impacts of the upstream development on properties. REFERENCES 1. "El Paso County Drainage Criteria Manual" and updates. 2. "El Paso County Engineering Criteria Manual", October 14, 2020 (revised). 3. The United States Department of Agriculture, Natural Resources Conservation Service, “Web Soil Survey” data for the project site, retrieved from http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.asp. 4. Federal Emergency Management Agency Firmette for Flood Insurance Rate Map Number 08041C0278G, dated 12/7/2018. 5. Final Drainage for Monument Marketplace Filing No. , prepared by Westworks Engineering, May 1, 2019. ---PAGE BREAK--- APPENDIX Hydrologic Calculations Hydraulic Calculations Reference Information Developed Drainage Plan ---PAGE BREAK--- Designer: Company: Date: Project Name: Project Number: Hydrological Soil Group: B Imperviousness: 100% 100% 90% 80% 0% C2: 0.89 0.89 0.71 0.57 0.02 C5: 0.90 0.90 0.73 0.59 0.08 C100: 0.96 0.96 0.81 0.70 0.35 Area Area Area Area Area Imp. (ac.) % 15,684 1,582 1,060 0 8,908 27,234 0.63 66.9% 0.60 0.63 0.75 3,750 908 1,122 0 5,562 11,342 0.26 50.0% 0.45 0.48 0.65 Paved Drives Concrete/ Walks Roofs Gravel Roads Lawns/ Native C2 A4a A2a C5 C100 Calculation of Imperviousness and Runoff Coefficient Values Land Use: SMS CIVAS Engineering, LLC Imp and Sub-Basin Name 11/7/2023 Ziggi's Monument 23-315 Sub-Basin Composite Imperviousness and Runoff Coefficient Values ---PAGE BREAK--- Designer: Notes: Company: Ti = (0.395*(1.1 - C5)*Li^0.5)/(Si^0.33) Cv = 2.5 Heavy Meadow Date: Tt=L/60V (Velocity = Cv*Sw^0.5) 5.0 Tillage / Field Project Name: 6.5 Rip Rap (not buried) Project Number: Tc Check = (26 -17*Imp) + Lt /((60*(14*Imp-9)*St^) 7.0 Short Pasture and Lawns 10.0 Nearly Bare Ground Area Description: 15.0 Grassed Waterway 20.0 Paved Areas and Shallow Paved Swales tc Final tc Area Length Slope Length Slope Velocity Length (Li) (Si) (Lt) (St) Imp (Lt) Min tc acres feet % minutes feet % ft/sec minutes minutes decimal feet minutes minutes A2a 0.63 0.63 45 2.0 4.6 275 0.7 20.0 1.67 2.7 7.3 0.67 275 17.6 7.3 A4a 0.48 0.26 35 2.0 5.3 230 0.9 20.0 1.90 2.0 7.3 0.50 230 20.0 7.3 23-315 Standard Form SF-1, Time of Concentration SMS CIVAS Engineering, LLC 11/7/2023 Ziggi's Monument Urbanized Area min. tc = 5 min. Sub-Basin Initial/Overland Time Travel Time First Design Point Remarks Data (ti) (tt) (Urbanized Basins) Basin Design. C5 ti Cv tt tc = ti+ tt ---PAGE BREAK--- Designer: Company: Note: Date: Design Storm: I5 = -1.50 x ln(tc) + 7.583 Project Name: Project Number: STREET Area tc I Q tc I Q Slope Street Flow Design Flow Slope Pipe Size Length Velocity tt REMARKS ac. min. in/hr cfs min. in/hr cfs % cfs cfs % in ft ft/sec min 1 A2a 0.63 0.63 7.3 0.39 4.60 1.8 1.8 2 A4a 0.26 0.48 7.3 0.13 4.60 0.6 0.6 Travel Time Design Point Basin Desig. Runoff Coeff. C*A Σ(C*A) Pipe 23-315 Direct Runoff Total Runoff Street Ziggi's Monument Standard Form SF-2, Storm Drainage System Design (Rational Method Procedure) SMS CIVAS Engineering, LLC 11/7/2023 5-year Page 1 ---PAGE BREAK--- Designer: Company: Note: Date: Design Storm: I100 = -2.52 x ln(tc) + 12.735 Project Name: Project Number: STREET Area tc I Q tc I Q Slope Street Flow Design Flow Slope Pipe Size Length Velocity tt REMARKS ac. min. in/hr cfs min. in/hr cfs % cfs cfs % in ft ft/sec min 1 A2a 0.63 0.75 7.3 0.47 7.73 3.6 3.6 2 A4a 0.26 0.65 7.3 0.17 7.73 1.3 1.3 Travel Time Design Point Basin Desig. Runoff Coeff. C*A Σ(C*A) Pipe 23-315 Direct Runoff Total Runoff Street Ziggi's Monument Standard Form SF-2, Storm Drainage System Design (Rational Method Procedure) SMS CIVAS Engineering, LLC 11/7/2023 100-year Page 2 ---PAGE BREAK--- FLOW CAPACITY CALCULATION WORKSHEET FOR with 1.00 ft bottom width Vertical left side slope Vertical right side slope Input Data Channel Depth: 0.13 ft. Material: conc Mannings Coefficient: 0.013 Bottom Width: 1.00 ft. Left Side Slope: Vertical 10000 Right Side Slope: Vertical 10000 Channel Top Width: 1.0 ft. Longitudinal Slope: 2.00 % Assumed Depth of Flow: 0.26 ft. Calculation Results cross-sectional area: 0.26 s.f. wetted perimeter: 1.52 ft. Capacity: 1.30 cfs Velocity: 4.99 fps Velocity Head: 0.39 ft. Gutter Capacity = 1.30 cfs 100-year Flow = 1.30 cfs Concrete Gutter at ramp Basin 4a Page 1 ---PAGE BREAK--- TRAPEZOIDAL CHANNEL FLOW CAPACITY CALCULATION WORKSHEET FOR Project Name: Ziggi's Monument Project No: 23-315 with 1.00 ft bottom width 2 : 1 left side slope 2 : 1 right side slope Input Data Channel Depth: 0.33 ft. Material: conc Mannings Coefficient: 0.013 Bottom Width: 1.00 ft. Left Side Slope: 50 % 50 Right Side Slope: 50 % 50 Channel Top Width: 2.3 ft. Longitudinal Slope: 2.00 % Assumed Depth of Flow: 0.20 ft. Calculation Results cross-sectional area: 0.28 s.f. wetted perimeter: 1.89 ft. Capacity: 1.27 cfs Velocity: 4.52 fps OK Velocity Head: 0.32 ft. Curb Cut Channel Flow: 1.3 cfs 100-yr Design Flow: 1.3 OK 1' wide curb cut - Basin 4a Page 1 ---PAGE BREAK--- 1.0' WIDE CURB CUT INTO LANDSCAPE AREA 1.0' WIDE RECTANGULAR CHASE DRAIN, Q100 = 1.3 CFS ASSUMPTIONS: Yt / D = 0.4, VMAX = 5.0 fps, Q/WH^0.5 = 1.3 / 1.0*0.2^0.5 = 2.9 FROM FIGURE 9-39 - USE: TYPE L RIPRAP FOR A MIN. DISTANCE OF 3 x H - 3 X 0.2' = 0.6' Width = 3 x W = 3 x 1.0 = 3.0 ft FROM FIGURE 8-34 - d50 = 9" USE 3 ft W x 3.0 ft L TYPE L RIPRAP, d50 = 9" RIP RAP CALCULATIONS - Basin 4a Page 1 ---PAGE BREAK--- Chapter 9 Hydraulic Structures January 2016 Urban Drainage and Flood Control District 9-77 Urban Storm Drainage Criteria Manual Volume 2 Figure 9-39. Riprap erosion protection at rectangular conduit outlet (valid for Q/WH1.5 d 8.0) 3.2.4 Outfalls and Rundowns A grouted boulder outfall or “rundown” can be used as a means to dissipate energy and provide erosion control protection. Grouted boulder outfalls are most commonly used in large rivers like the South Platte. Figure 9-40 provides a plan view and cross section for a standard grouted boulder rundown. See the grouted boulder drop profiles (A1, A2, and A3) in Figure 9-12 for site specific profile options, depressed or free-draining basin for use with a stable channel or with no basin for use in channels subject to degradation). Figure 9-41 provides a plan view of the same structure for use when the structure is in-line with the channel. Evaluate the following when designing a grouted boulder outfall or rundown: Minimize disturbance to channel bank Determine water surface elevation in receiving channel for base flow and design storm(s) Determine flow rate, velocity, depth, etc. of flow exiting the outfall pipe for the design storm(s) Evaluate permitting procedures and requirements for construction adjacent to large river system. ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- LOT 1 JACKSON CREEK PARKWAY (RECEPTION NO. 203270646) (120' R.O.W.) SEC. 23 SEC. 26 N89°08'44"E 197.75' N89°08'44"E 196.42' LOT 3 S00°28'12"E 198.00' LOT 5A LOT 3 VILLAGE AT JACKSON CREEK FIL. NO. 1 REC. NO. 216713728 BASIS OF BEARINGS N00°51'16"E 198.00' N SUMMARY RUNOFF TABLE 811 10056 Brisbane Lane Littleton Colorado 80130 [PHONE REDACTED] civas-eng.com engineering CIVAS civil engineering solutions LEGEND: