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HomeMy WebLinkAboutPSD PROSPECT SCHOOL SITE SITE PLAN ADVISORY REVIEW - SPA190002 - SUBMITTAL DOCUMENTS - ROUND 1 - DRAINAGE REPORTOctober 9, 2019 PRELIMINARY DRAINAGE AND EROSION CONTROL REPORT FOR PSD MIDDLE SCHOOL HIGH SCHOOL #2 Fort Collins, Colorado Prepared for: Poudre School District Ft.Collins, CO Prepared by: 301 N. Howes, Suite 100 Fort Collins, Colorado 80521 Phone: 970.221.4158 Fax: 970.221.4159 www.northernengineering.com Project Number: 100-024  This Drainage Report is consciously provided as a PDF. Please consider the environment before printing this document in its entirety. When a hard copy is absolutely necessary, we recommend double-sided printing. October 9, 2019 City of Fort Collins Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Preliminary Drainage and Erosion Control Report for PSD Middle School High School #2 Dear Staff: Northern Engineering is pleased to submit this Preliminary Drainage and Erosion Control Report for your review. This report accompanies the Preliminary Plan submittal for the proposed PSD Middle School Hight School #2 development. This report has been prepared in accordance to State of Colorado Drainage Criteria, and serves to document the stormwater impacts associated with the proposed project. The project area lies within City of Fort Collins jurisdiction and therefore we have followed current drainage criteria for this locality. If you should have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. Aaron Cvar, PhD, PE Senior Project Engineer PSD Middle School High School #2 Preliminary Drainage Report TABLE OF CONTENTS I. GENERAL LOCATION AND DESCRIPTION ................................................................... 1 A. Location ............................................................................................................................................. 1 B. Description of Property ..................................................................................................................... 2 C. Floodplain.......................................................................................................................................... 4 II. DRAINAGE BASINS AND SUB-BASINS ....................................................................... 4 A. Major Basin Description .................................................................................................................... 4 B. Sub-Basin Description ....................................................................................................................... 4 III. DRAINAGE DESIGN CRITERIA ................................................................................... 5 A. Regulations........................................................................................................................................ 5 B. Four Step Process .............................................................................................................................. 5 C. Development Criteria Reference and Constraints ............................................................................ 6 D. Hydrological Criteria ......................................................................................................................... 6 E. Hydraulic Criteria .............................................................................................................................. 7 F. Modifications of Criteria ................................................................................................................... 7 IV. DRAINAGE FACILITY DESIGN .................................................................................... 8 A. General Concept ............................................................................................................................... 8 B. Specific Details .................................................................................................................................. 9 V. CONCLUSIONS ...................................................................................................... 10 A. Compliance with Standards ............................................................................................................ 10 B. Drainage Concept ............................................................................................................................ 10 APPENDICES: APPENDIX A – Hydrologic Computations and Supporting Documentation APPENDIX B – Water Quality Computations and Information APPENDIX C – Detention Computations, SWMM Output APPENDIX D – Erosion Control Report APPENDIX E – USDA Soils Information PSD Middle School High School #2 Preliminary Drainage Report LIST OF FIGURES: Figure 1 – Aerial Photograph ................................................................................................ 2 Figure 2– Proposed Site Plan ................................................................................................ 3 Figure 3 – Existing Floodplains ............................................................................................. 4 MAP POCKET: Proposed Drainage Exhibit PSD Middle School High School #2 Preliminary Drainage Report 1 I. GENERAL LOCATION AND DESCRIPTION A. Location 1. Vicinity Map 2. The project site is located in the south half of Section 15, Township 7 North, Range 68 West of the 6th Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 3. The project site is located just northwest of the intersection of Prospect Rd. and County Road 5. 4. Existing residential developments, Kitchell Subdivision exists to the north of the site; Homestead Subdivision exists to the south of the site. 5. Offsite flows enter the site from the north per the Town of Timnath Master Drainage Plan Update (Ref. 5). Historic flows convey via sheet flow south west towards the existing Timnath Reservioir Inlet Canal (TRIC) embankment and pass under the embankment through several existing pipes, as well as via sheet flow across the top of the ditch at certain locations. PSD Middle School High School #2 Preliminary Drainage Report 2 B. Description of Property 1. The proposed development area is roughly 93 acres in size. Figure 1 – Aerial Photograph 2. The subject property is currently composed of undeveloped farmland. Existing ground slopes are mild to moderate (i.e., 1 - 6±%) through the interior of the property. Historic drainage patterns direct flows generally from north to south and drain via sheet flow collecting within several existing pipes and enter the Timnath Reservoir Inlet Canal (TRIC) at several locations. There are also point of discharge into the TRIC where sheet flow prevails, and historic flows enter the canal across the canal north top of bank. 3. The proposed site design will include Extended Detention water quality treatment prior to stormwater discharge from the site. Water quality treatment methods are described in further detail below. 4. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey website: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx, the site primarily consists of Loveland Clay Loam, which falls into Hydrologic Soil Group C. PROJECT SITE PSD Middle School High School #2 Preliminary Drainage Report 3 5. The proposed project site plan is composed of a middle school and high school with associated parking, utilities, and drives. Onsite detention water quality treatment is proposed and will consist features which are discussed in Section IV. Figure 2– Proposed Site Plan 6. The proposed land use is a middle school and high school site. PSD Middle School High School #2 Preliminary Drainage Report 4 C. Floodplain 1. The project site is not encroached by any FEMA jurisdictional flood zone. Additionally, the site is not encroached by any City designated flood zones, as shown in Figure 3, below. Figure 3 –Area Floodplain Mapping II. DRAINAGE BASINS AND SUB-BASINS A. Major Basin Description 1. The project site lies within the Town of Timnath Master Drainage Plan Update (Ref. 5) study area. According to the Town Master Drainage Plan, Basins SB5 and SB5A are allowed to release 57 cfs (Link 105C) while Basins SB15 and SB15A are allowed to release 28 cfs (Link 115AB). Thus, a total allowable release of 85 cfs is allowed into the TRIC from these basins. Please excerpts from the Town Master Drainage Plan provided in the Appendix. 2. Due to work required along Prospect Road Basins R1 through R3 will release undetained into the TRIC from Prospect Road. A total 100-year discharge from these basins of 40.3 cfs will be released undetained into the TRIC as a result of the widened roadway. This amount must be subtracted from the overall allowable release rate for the project, leaving an allowable release rate of 44.7 cfs for the project site to release into the TRIC. B. Sub-Basin Description 1. Historic drainage patterns direct flows generally from north to south and drain via sheet flow collecting within several existing pipes and enter the Timnath Reservoir PROJECT SITE PSD Middle School High School #2 Preliminary Drainage Report 5 Inlet Canal (TRIC) at several locations. There are also point of discharge into the TRIC where sheet flow prevails, and historic flows enter the canal across the canal north top of bank. 2. A more detailed description of the project drainage patterns is provided below. III. DRAINAGE DESIGN CRITERIA A. Regulations There are no optional provisions outside of the FCSCM proposed with the proposed project. B. Four Step Process The overall stormwater management strategy employed with the proposed project utilizes the “Four Step Process” to minimize adverse impacts of urbanization on receiving waters. The following is a description of how the proposed development has incorporated each step. Step 1 – Employ Runoff Reduction Practices Several techniques have been utilized with the proposed development to facilitate the reduction of runoff peaks, volumes, and pollutant loads as the site is developed from the current use by implementing multiple Low Impact Development (LID) strategies including: Conserving existing amenities in the site including the existing vegetated areas. Providing vegetated open areas throughout the site to reduce the overall impervious area and to minimize directly connected impervious areas (MDCIA). Routing flows, to the extent feasible, through vegetated swales to increase time of concentration, promote infiltration and provide initial water quality. Step 2 – Implement BMPs That Provide a Water Quality Capture Volume (WQCV) with Slow Release The efforts taken in Step 1 will facilitate the reduction of runoff; however, urban development of this intensity will still generate stormwater runoff that will require additional BMPs and water quality. The majority of stormwater runoff from the site will ultimately be intercepted and treated using detention and LID treatment methods prior to exiting the site. Step 3 – Stabilize Drainageways There are no major drainageways within the subject property. While this step may not seem applicable to proposed development, the project indirectly helps achieve stabilized drainageways nonetheless. By providing water quality treatment, where none previously existed, sediment with erosion potential is removed from downstream drainageway systems. Furthermore, this project will pay one-time stormwater development fees, as well as ongoing monthly stormwater utility fees, both of which help achieve City-wide drainageway stability. Step 4 – Implement Site Specific and Other Source Control BMPs. The proposed project will improve upon site specific source controls compared to historic conditions: The proposed development will provide LID and water quality treatment; thus, eliminating sources of potential pollution previously left exposed to weathering and runoff processes. PSD Middle School High School #2 Preliminary Drainage Report 6 C. Development Criteria Reference and Constraints The subject property is surrounded by currently developed properties. Thus, several constraints have been identified during the course of this analysis that will impact the proposed drainage system including: Existing elevations along the property lines will generally be maintained. As previously mentioned, overall drainage patterns of the existing site will be maintained. Elevations of existing downstream facilities that the subject property will release to will be maintained. D. Hydrological Criteria 1. The City of Fort Collins Rainfall Intensity-Duration-Frequency Curves, as depicted in Figure 3.4-1 of the FCSCM, serve as the source for all hydrologic computations associated with the proposed development. Tabulated data contained in Table 3.4-1 has been utilized for Rational Method runoff calculations. 2. The Rational Method has been employed to compute stormwater runoff utilizing runoff coefficients contained and frequency adjustment factors in Tables 3.2-2 and 3.2-3 of the FCSCM. Table 3.2-2 –Surface Type – Runoff Coefficients (City of Fort Collins Stormwater Criteria Manual, Ref.1) PSD Middle School High School #2 Preliminary Drainage Report 7 Table 3.2-3 –Frequency Adjustment Factors (City of Fort Collins Stormwater Criteria Manual, Ref.1) 3. Three separate design storms have been utilized to address distinct drainage scenarios. A fourth design storm has also been computed for comparison purposes. The first design storm considered is the 80th percentile rain event, which has been employed to design the project’s water quality features. The second event analyzed is the “Minor,” or “Initial” Storm, which has a 2-year recurrence interval. The third event considered is the “Major Storm,” which has a 100-year recurrence interval. The fourth storm computed, for comparison purposes only, is the 10-year event. 4. No other assumptions or calculation methods have been used with this development that are not referenced by current City of Fort Collins criteria. E. Hydraulic Criteria 1. As previously noted, the subject property maintains historic drainage patterns. 2. All drainage facilities proposed with the project are designed in accordance with criteria outlined in the FCSCM and/or the Urban Drainage and Flood Control District (UDFCD) Urban Storm Drainage Criteria Manual. 3. As stated above, the subject property is not located in a FEMA designated floodplain, or within a City designated floodplain and floodway. The proposed project does not propose to modify any natural drainageways. F. Modifications of Criteria 1. The proposed development is not requesting any modifications to criteria at this time. PSD Middle School High School #2 Preliminary Drainage Report 8 IV. DRAINAGE FACILITY DESIGN A. General Concept 1. The main objectives of the project drainage design are to maintain existing drainage patterns, and to ensure no adverse impacts to any adjacent properties. 2. LID and water quality treatment will be provided in the form of forebays, extended detention, and an existing wet pond, as discussed further below. 3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are described below. Drainage basins have been defined for preliminary design purposes and are subject to change at Final design; however, general drainage patterns and concepts are not expected to be significantly altered. Basins 1 and 2 Basins 1 and 2 consist of a stadium area, drives and parking areas, as well as landscaped areas. Drainage from these basins will be conveyed via drive and parking area curb and gutter as well as across landscaped areas to proposed storm sewer systems, which will direct developed runoff into Pond 4. This pond will provide attenuation prior to conveyance into the main onsite detention pond, Pond 1. Pond 1 will release detained, treated flows into the Timnath Reservoir Inlet Canal (TRIC). Basins 3 – 9, 12 Basins 3 through 9, and Basin 12 consist of main school buildings, drives and parking areas, and playfields. Drainage from these basins will be conveyed via drive and parking area curb and gutter as well as across playfield areas to proposed storm sewer systems, which will direct developed runoff into Ponds 2 and 3. These ponds will provide attenuation prior to conveyance into the main onsite detention pond, Pond 1. Pond 1 will release detained, treated flows into the Timnath Reservoir Inlet Canal (TRIC). Basins 10 and 11 Basins 10 and 11 consist of main parking areas, landscaped areas, and drives. Drainage from these basins will be conveyed via drive and parking area curb and gutter as well as across landscaped areas to proposed storm sewer systems, which will direct developed runoff into Ponds 2 and 3. These pond will provide attenuation prior to conveyance into the main onsite detention pond, Pond 1. Pond 1 will release detained, treated flows into the Timnath Reservoir Inlet Canal (TRIC). Basin OS1 Basin OS1 consists of anticipated future development area and is encompassed by a proposed roadway associated with the project. This site is anticipated to provide its own detention and water quality and release into Timnath Reservoir Inlet Canal (TRIC) in the near future. A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. PSD Middle School High School #2 Preliminary Drainage Report 9 B. Specific Details 1. Standard water quality treatment in the form of Extended Detention is being provided for the overall proposed development within the lower stage of Pond 1. We have computed required extended detention volume based on the standard water quality treatment for 100% of site runoff. Please see Water Quality Capture Volume (Extended Detention) computations provided in the Appendix. 2. The overall site drains a series of 4 detention ponds. Ponds 2 through 4 will provide minor attenuation and have fairly high release rates. Pond 1 is the final in-series pond that will fully control developed site runoff and control 100-year release to the allowable release rate into the Timnath Reservoir Inlet Canal (TRIC). 3. Please see Table 1, below, for a summary of proposed detention and water quality to be provided onsite. POND SUMMARY TABLE Pond ID 100-Yr. Detention Vol. (Ac-Ft) Water Quality Capture Volume (Ac-Ft) Total Req'd Vol. (Ac- Ft) Peak Release (cfs) Pond 1 25.62 1.39 27.01 33.20 Pond 2 1.52 N/A 1.52 119.20 Pond 3 0.76 N/A 0.76 59.90 Pond 4 1.42 N/A 1.42 11.20 PSD Middle School High School #2 Preliminary Drainage Report 10 V. CONCLUSIONS A. Compliance with Standards 1. The drainage design proposed with the proposed project complies with the City of Fort Collins’ Stormwater Criteria Manual. 2. The drainage design proposed with this project complies with requirements for the Town of Timnath Master Drainage Plan Update. 3. The drainage plan and stormwater management measures proposed with the proposed development are compliant with all applicable State and Federal regulations governing stormwater discharge. B. Drainage Concept 4. The drainage design proposed with this project will effectively limit any potential damage associated with its stormwater runoff by providing detention and water quality mitigation features. 5. The drainage concept for the proposed development is consistent with requirements for the Town of Timnath Master Drainage Plan Update. PSD Middle School High School #2 Preliminary Drainage Report 11 References 1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, December 2018. 2. Larimer County Urban Area Street Standards, Adopted January 2, 2001, Repealed and Reenacted, Effective October 1, 2002, Repealed and Reenacted, Effective April 1, 2007. 3. Soils Resource Report for Larimer County Area, Colorado, Natural Resources Conservation Service, United States Department of Agriculture (https://websoilsurvey.sc.egov.usda.gov/App/ Data upload February 2019) 4. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright-McLaughlin Engineers, Denver, Colorado, Revised April 2008. 5. Town of Timnath Master Drainage Plan Update, Ayres Associates, Revised November, 2018. APPENDIX A Hydrologic Computations and Supporting Documentation CHARACTER OF SURFACE: Runoff Coefficient Percentage Impervious Project: 100-024 Streets, Parking Lots, Roofs, Alleys, and Drives: Calculations By: ATC Asphalt ……....……………...……….....…...……………….………………………………….. 0.95 100% Date: Concrete …….......……………….….……….………………..….…………………………………0.95 90% Gravel ……….…………………….….…………………………..……………………………….. 0.50 40% Roofs …….…….………………..……………….…………………………………………….. 0.95 90% Pavers…………………………...………………..…………………………………………….. 0.50 40% Lawns and Landscaping Sandy Soil ……..……………..……………….…………………………………………….. 0.15 0% Clayey Soil ….….………….…….…………..………………………………………………. 0.25 0% 2-year Cf = 1.00 100-year Cf = 1.25 Basin ID Basin Area (s.f.) Basin Area (ac) Area of Asphalt (ac) Area of Concrete (ac) Area of Roofs (ac) Area of Gravel (ac) Area of Lawn, Rain Garden, or Landscaping (ac) 2-year Composite Runoff Coefficient 10-year Composite Runoff Coefficient 100-year Composite Runoff Coefficient Composite % Imperv. 1 303281 6.96 2.65 0.21 0.14 0.00 3.97 0.55 0.55 0.69 43% 2 263464 6.05 1.21 0.18 0.12 0.00 4.54 0.43 0.43 0.53 25% 3 435970 10.01 5.00 0.80 0.20 0.00 4.00 0.67 0.67 0.84 59% 4 427045 9.80 3.14 0.29 0.20 0.00 6.18 0.51 0.51 0.64 37% 5 183858 4.22 0.93 0.13 0.00 0.00 3.17 0.43 0.43 0.53 25% 6 398755 9.15 1.19 0.27 0.00 0.00 7.69 0.36 0.36 0.45 16% 7 257810 5.92 1.12 0.18 0.00 0.00 4.62 0.40 0.40 0.51 22% 8 112809 2.59 0.67 0.08 0.00 0.00 1.84 0.45 0.45 0.57 29% 9 151125 3.47 0.35 0.07 0.00 0.00 3.05 0.33 0.33 0.42 12% Overland Flow, Time of Concentration: Project: 100-024 Calculations By: Date: Gutter/Swale Flow, Time of Concentration: Tt = L / 60V Tc = T i + Tt (Equation RO-2) Velocity (Gutter Flow), V = 20·S ½ Velocity (Swale Flow), V = 15·S ½ NOTE: C-value for overland flows over grassy surfaces; C = 0.25 Is Length >500' ? C*Cf (2-yr Cf=1.00) C*Cf (10-yr Cf=1.00) C*Cf (100-yr Cf=1.25) Length, L (ft) Slope, S (%) Ti 2-yr (min) Ti 10-yr (min) Ti 100-yr (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Tt (min) Length, L (ft) Slope, S (%) Velocity, V (ft/s) Rational Method Equation: Project: 100-024 Calculations By: Date: From Section 3.2.1 of the CFCSDDC Rainfall Intensity: 1 1 6.96 15 15 15 0.55 0.55 0.69 1.90 3.24 6.62 7.27 12.43 31.72 2 2 6.05 11 11 11 0.43 0.43 0.53 2.17 3.71 7.57 5.58 9.52 24.32 3 3 10.01 14 14 14 0.67 0.67 0.84 1.92 3.29 6.71 12.87 22.06 56.24 4 4 9.80 14 14 14 0.51 0.51 0.64 1.95 3.34 6.82 9.73 16.67 42.51 5 5 4.22 14 14 14 0.43 0.43 0.53 1.92 3.29 6.71 3.44 5.90 15.05 6 6 9.15 11 11 11 0.36 0.36 0.45 2.17 3.71 7.57 7.19 12.28 31.36 7 7 5.92 10 10 10 0.40 0.40 0.51 2.21 3.78 7.72 5.28 9.04 23.07 8 8 2.59 12 12 12 0.45 0.45 0.57 2.09 3.57 7.29 2.45 4.18 10.69 9 9 3.47 13 13 13 0.33 0.33 0.42 2.02 3.45 7.04 2.33 3.99 10.20 10 10 8.35 9 9 9 0.64 0.64 0.80 2.35 4.02 8.21 12.60 21.53 55.00 11 11 5.89 10 10 10 0.80 0.80 1.00 2.21 3.78 7.72 10.36 17.71 45.22 12 12 13.70 11 11 11 0.29 0.29 0.36 2.17 3.71 7.57 8.48 14.47 36.96 R1 R1 4.03 10 10 10 0.45 0.45 0.56 2.26 3.86 7.88 4.05 6.92 17.67 R2 R2 2.57 10 10 10 0.49 0.49 0.61 2.26 3.86 7.88 2.83 4.84 12.35 R3 R3 2.13 9 9 9 0.48 0.48 0.60 2.30 3.93 8.03 2.36 4.02 10.28 OS1 OS1 13.80 15 15 15 0.78 0.78 0.98 1.87 3.19 6.52 20.18 34.42 87.95 Area, A (acres) Intensity, i2 (in/hr) 100-yr Tc (min) RUNOFF COMPUTATIONS C100 Design Point Flow, Q100 (cfs) Flow, Q2 (cfs) 10-yr Tc (min) 2-yr Tc (min) C2 Flow, Q10 (cfs) Intensity, i100 (in/hr) Basin(s) ATC October 7, 2019 Intensity, i10 (in/hr) Rainfall Intensity taken from the City of Fort Collins Storm Drainage Design Criteria (CFCSDDC), Figure 3.1 C10 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.2 Runoff Coefficients Page 4 3.2 Runoff Coefficients Runoff coefficients used for the Rational Method are determined based on either overall land use or surface type across the drainage area. For Overall Drainage Plan (ODP) submittals, when surface types may not yet be known, land use shall be used to estimate flow rates and volumes. Table 3.2-1 lists the runoff coefficients for common types of land uses in the City. Table 3.2-1. Zoning Classification - Runoff Coefficients Land Use Runoff Coefficient (C) Residential Urban Estate 0.30 Low Density 0.55 Medium Density 0.65 High Density 0.85 Commercial Commercial 0.85 Industrial 0.95 Undeveloped Open Lands, Transition 0.20 Greenbelts, Agriculture 0.20 Reference: For further guidance regarding zoning classifications, refer to the Land Use Code, Article 4. For a Project Development Plan (PDP) or Final Plan (FP) submittals, runoff coefficients must be based on the proposed land surface types. Since the actual runoff coefficients may be different from those specified in Table 3.2-1, Table 3.2-2 lists coefficients for the specific types of land surfaces. FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.2 Runoff Coefficients Page 5 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 0.80 Gravel 0.50 Pavers 0.50 Landscape or Pervious Surface Lawns, Sandy Soil, Flat Slope < 2% 0.10 Lawns, Sandy Soil, Avg Slope 2-7% 0.15 Lawns, Sandy Soil, Steep Slope >7% 0.20 Lawns, Clayey Soil, Flat Slope < 2% 0.20 Lawns, Clayey Soil, Avg Slope 2-7% 0.25 Lawns, Clayey Soil, Steep Slope >7% 0.35 3.2.1 Composite Runoff Coefficients Drainage sub-basins are frequently composed of land that has multiple surface types or zoning classifications. In such cases a composite runoff coefficient must be calculated for any given drainage sub-basin. The composite runoff coefficient is obtained using the following formula: ( ) t n i i i A C xA C ∑ = = 1 Equation 5-2 Where: C = Composite Runoff Coefficient Ci = Runoff Coefficient for Specific Area (Ai), dimensionless Ai = Area of Surface with Runoff Coefficient of Ci, acres or square feet n = Number of different surfaces to be considered At = Total Area over which C is applicable, acres or square feet 3.2.2 Runoff Coefficient Frequency Adjustment Factor The runoff coefficients provided in Table 3.2-1 and Table 3.2-2 are appropriate for use with the 2-year storm event. For any analysis of storms with higher intensities, an adjustment of the runoff coefficient is required due to the lessening amount of infiltration, depression retention, evapotranspiration and other losses that have a proportionally smaller effect on high-intensity storm runoff. This adjustment is FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.3 Time of Concentration Page 6 applied to the composite runoff coefficient. These frequency adjustment factors, Cf, are found in Table 3.2-3. Table 3.2-3. Frequency Adjustment Factors Storm Return Period (years) Frequency Adjustment Factor (Cf) 2, 5, 10 1.00 25 1.10 50 1.20 100 1.25 3.3 Time of Concentration 3.3.1 Overall Equation The next step to approximate runoff using the Rational Method is to estimate the Time of Concentration, Tc, or the time for water to flow from the most remote part of the drainage sub-basin to the design point under consideration. The Time of Concentration is represented by the following equation: 𝐓𝐓𝐜𝐜 = 𝐓𝐓 𝐢𝐢 + 𝐓𝐓𝐭𝐭 Equation 5-3 Where: Tc = Total Time of Concentration, minutes Ti = Initial or Overland Flow Time of Concentration, minutes Tt = Channelized Flow in Swale, Gutter or Pipe, minutes 3.3.2 Overland Flow Time Overland flow, Ti, can be determined by the following equation: 𝐓𝐓𝐢𝐢 = 𝟏𝟏.𝟖𝟖𝟖𝟖(𝟏𝟏.𝟏𝟏−𝐂𝐂𝐂𝐂𝐂𝐂𝐟𝐟)√𝐋𝐋 √𝐒𝐒 𝟑𝟑 Equation 3.3-2 Where: C = Runoff Coefficient, dimensionless Cf = Frequency Adjustment Factor, dimensionless L = Length of Overland Flow, feet S = Slope, percent CXCF PRODUCT OF CXCF CANNOT EXCEED THE VALUE OF 1 OVERLAND FLOW LENGTH L=200’ MAX IN DEVELOPED AREAS L=500’ MAX IN UNDEVELOPED AREAS FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 7 3.3.3 Channelized Flow Time Travel time in a swale, gutter or storm pipe is considered “channelized” or “concentrated” flow and can be estimated using the Manning’s Equation: 𝐕𝐕 = 𝟏𝟏.𝟒𝟒𝟒𝟒 𝐧𝐧 𝐑𝐑𝟐𝟐/𝟑𝟑 𝐒𝐒𝟏𝟏/𝟐𝟐 Equation 5-4 Where: V = Velocity, feet/second n = Roughness Coefficient, dimensionless R = Hydraulic Radius, feet (Hydraulic Radius = area / wetted perimeter, feet) S = Longitudinal Slope, feet/feet And: 𝐓𝐓𝐭𝐭 = 𝐋𝐋 𝐕𝐕𝐂𝐂𝐕𝐕𝐕𝐕 Equation 5-5 3.3.4 Total Time of Concentration A minimum Tc of 5 minutes is required. The maximum Tc allowed for the most upstream design point shall be calculated using the following equation: 𝐓𝐓𝐜𝐜 = 𝐋𝐋 𝟏𝟏𝟖𝟖𝐕𝐕 + 𝟏𝟏𝐕𝐕 Equation 3.3-5 The Total Time of Concentration, Tc, is the lesser of the values of Tc calculated using Tc = Ti + Tt or the equation listed above. 3.4 Intensity-Duration-Frequency Curves for Rational Method The two-hour rainfall Intensity-Duration-Frequency curves for use with the Rational Method is provided in Table 3.4-1 and Figure 3.4-1. TC • A MINIMUM TC OF 5 MINUTES IS REQUIRED IN ALL CASES. • A MAXIMUM TC OF 5 MINUTES IS TYPICAL FOR SMALLER, URBAN PROJECTS. FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 8 Table 3.4-1. IDF Table for Rational Method Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) Duration (min) Intensity 2-year (in/hr) Intensity 10-year (in/hr) Intensity 100-year (in/hr) 5 2.85 4.87 9.95 39 1.09 1.86 3.8 6 2.67 4.56 9.31 40 1.07 1.83 3.74 7 2.52 4.31 8.80 41 1.05 1.80 3.68 8 2.40 4.10 8.38 42 1.04 1.77 3.62 9 2.30 3.93 8.03 43 1.02 1.74 3.56 10 2.21 3.78 7.72 44 1.01 1.72 3.51 11 2.13 3.63 7.42 45 0.99 1.69 3.46 12 2.05 3.50 7.16 46 0.98 1.67 3.41 13 1.98 3.39 6.92 47 0.96 1.64 3.36 14 1.92 3.29 6.71 48 0.95 1.62 3.31 15 1.87 3.19 6.52 49 0.94 1.6 3.27 16 1.81 3.08 6.30 50 0.92 1.58 3.23 17 1.75 2.99 6.10 51 0.91 1.56 3.18 18 1.70 2.90 5.92 52 0.9 1.54 3.14 19 1.65 2.82 5.75 53 0.89 1.52 3.10 20 1.61 2.74 5.60 54 0.88 1.50 3.07 21 1.56 2.67 5.46 FORT COLLINS STORMWATER CRITERIA MANUAL Hydrology Standards (Ch. 5) 3.0 Rational Method 3.4 Intensity-Duration-Frequency Curves for Rational Method Page 9 Figure 3.4-1. Rainfall IDF Curve – Fort Collins APPENDIX B Water Quality and LID Computations and Information WATER QUALITY POND DESIGN CALCULATIONS Extended Detention (Lower Stage Pond 4) Project: 100-024 By: ATC Date:10/8/19 REQUIRED STORAGE & OUTLET WORKS: BASIN AREA = 86.120 <-- INPUT from impervious calcs BASIN IMPERVIOUSNESS PERCENT = 33.30 <-- INPUT from impervious calcs BASIN IMPERVIOUSNESS RATIO = 0.3330 <-- CALCULATED WQCV (watershed inches) = 0.161 <-- CALCULATED from Figure EDB-2 WQCV (ac-ft) = 1.390 <-- CALCULATED from UDFCD DCM V.3 Section 6.5 WQ Depth (ft) = TBD <-- INPUT from stage-storage table AREA REQUIRED PER ROW, a (in2) = TBD <-- CALCULATED from Figure EDB-3 CIRCULAR PERFORATION SIZING: dia (in) = TBD <-- INPUT from Figure 5 n = TBD <-- INPUT from Figure 5 t (in) = TBD <-- INPUT from Figure 5 number of rows = TBD <-- CALCULATED from WQ Depth and row spacing FORT COLLINS STORMWATER CRITERIA MANUAL Water Quality (Ch. 7) 5.0 Hydrologic Basis of the WQCV 5.0 Hydrologic Basis of the WQCV Page 12 WQCV = a(0.91I3− 1.19I2+ 0.78𝐼𝐼) Equation 7-1 Where: WQCV = Water Quality Capture Volume, watershed inches a = Coefficient corresponding to WQCV drain time (Table 5.4-1) I = Imperviousness (%/100) Table 5.4-1. Drain Time Coefficients for WQCV Calculations Drain Time (hrs) Coefficient (a) 12 0.8 40 1.0 Reference: The UD-BMP excel-based spreadsheet, RG and EDB tabs may be used to aid in calculating WQCV. Figure 5.4-1 WQCV Based on BMP Drain Time Once the WQCV in watershed inches is found from Figure 3.2-12 or using Equation 3.2-1, the required BMP volume in acre-feet can be calculated as follows: 𝐕𝐕 = � 𝐖𝐖𝐖𝐖𝐖𝐖𝐕𝐕 𝟏𝟏𝟏𝟏 � 𝐀𝐀𝐀𝐀𝟏𝟏. 𝟏𝟏 Equation 7-2 Where: V = required volume, acre-ft 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 APPENDIX C Detention Computations, SWMM Output Project: 100-024 By: ATC Date: 10/8/19 Pond ID 100-Yr. Detention Vol. (Ac-Ft) Water Quality Capture Volume (Ac- Ft) Total Req'd Vol. (Ac-Ft) Peak Release (cfs) Pond 1 25.62 1.39 27.01 33.20 Pond 2 1.52 N/A 1.52 119.20 Pond 3 0.76 N/A 0.76 59.90 Pond 4 1.42 N/A 1.42 11.20 POND SUMMARY TABLE Pond Stage-Storage Curve Pond:1 Project: 100-024 By: ATC Date: 10/7/19 Stage (FT) Contour Area (SF) Volume (CU.FT.) Volume (AC-FT) 4912.000 4947.69 0.00 0.000 4913.000 51425.16 38936.37 0.894 4914.000 165116.80 141832.85 3.256 4915.000 222489.05 334924.18 7.689 4916.000 252127.61 572078.12 13.133 4917.000 266295.63 831257.47 19.083 4918.000 280483.09 1104616.15 25.358 4918.500 336579.71 1258881.85 28.900 Pond Stage-Storage Curve Pond:2 Project: 100-024 By: ATC Date: 10/7/19 Stage (FT) Contour Area (SF) Volume (CU.FT.) Volume (AC-FT) 4912.00 1.22 0.00 0.000 4913.000 8450.11 2851.02 0.065 4914.000 14166.51 14036.94 0.322 4915.000 16454.48 29333.17 0.673 4916.000 18862.54 46977.98 1.078 4917.000 22000.74 67389.51 1.547 Pond Stage-Storage Curve Pond:3 Project: 100-024 By: ATC Date: 10/7/19 Stage (FT) Contour Area (SF) Volume (CU.FT.) Volume (AC-FT) 4913.000 6386.39 0.00 0.000 4914.000 13314.50 9640.72 0.221 4915.000 15574.33 24070.38 0.553 4916.000 17965.65 40826.14 0.937 4917.000 20488.44 60039.38 1.378 Pond Stage-Storage Curve Pond:4 Project: 100-024 By: ATC Date: 10/7/19 Stage (FT) Contour Area (SF) Volume (CU.FT.) Volume (AC-FT) 4,914.00 1,209.92 0 0.000 4,915.00 17,185.81 7651.9 0.176 4,916.00 27,279.40 29691.2 0.682 4,917.00 37,739.69 62059.77 1.425 EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.012) -------------------------------------------------------------- ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Units ............... CFS Process Models: Rainfall/Runoff ........ YES RDII ................... NO Snowmelt ............... NO Groundwater ............ NO Flow Routing ........... YES Ponding Allowed ........ NO Water Quality .......... NO Infiltration Method ...... HORTON Flow Routing Method ...... KINWAVE Starting Date ............ 01/01/2000 00:00:00 Ending Date .............. 01/06/2000 01:00:00 Antecedent Dry Days ...... 0.0 Report Time Step ......... 00:15:00 Wet Time Step ............ 00:05:00 Dry Time Step ............ 01:00:00 Routing Time Step ........ 30.00 sec ************************** Volume Depth Runoff Quantity Continuity acre-feet inches ************************** --------- ------- Total Precipitation ...... 60.670 3.669 Evaporation Loss ......... 0.000 0.000 Infiltration Loss ........ 25.327 1.532 Surface Runoff ........... 35.191 2.128 SWMM 5 Page 1 Final Storage ............ 0.319 0.019 Continuity Error (%) ..... -0.277 ************************** Volume Volume Flow Routing Continuity acre-feet 10^6 gal ************************** --------- --------- Dry Weather Inflow ....... 0.000 0.000 Wet Weather Inflow ....... 35.191 11.468 Groundwater Inflow ....... 0.000 0.000 RDII Inflow .............. 0.000 0.000 External Inflow .......... 0.000 0.000 External Outflow ......... 34.675 11.299 Flooding Loss ............ 0.110 0.036 Evaporation Loss ......... 0.000 0.000 Exfiltration Loss ........ 0.000 0.000 Initial Stored Volume .... 0.000 0.000 Final Stored Volume ...... 0.375 0.122 Continuity Error (%) ..... 0.089 ******************************** Highest Flow Instability Indexes ******************************** All links are stable. ************************* Routing Time Step Summary ************************* Minimum Time Step : 29.00 sec Average Time Step : 30.00 sec Maximum Time Step : 30.00 sec Percent in Steady State : 0.00 Average Iterations per Step : 1.00 Percent Not Converging : 0.00 *************************** Subcatchment Runoff Summary *************************** SWMM 5 Page 2 -------------------------------------------------------------------------------------------------------- Total Total Total Total Total Total Peak Runoff Precip Runon Evap Infil Runoff Runoff Runoff Coeff Subcatchment in in in in in 10^6 gal CFS -------------------------------------------------------------------------------------------------------- SM2 3.67 0.00 0.00 1.26 2.39 1.29 78.99 0.651 SM1 3.67 0.00 0.00 1.59 2.06 1.51 78.88 0.563 SM3 3.67 0.00 0.00 0.71 2.92 1.46 115.88 0.797 SB5A 3.67 0.00 0.00 1.49 2.18 1.95 101.31 0.594 SB15 3.67 0.00 0.00 1.83 1.85 4.36 144.17 0.503 SM4 3.67 0.00 0.00 1.15 2.50 0.89 59.34 0.681 ****************** Node Depth Summary ****************** --------------------------------------------------------------------------------- Average Maximum Maximum Time of Max Reported Depth Depth HGL Occurrence Max Depth Node Type Feet Feet Feet days hr:min Feet --------------------------------------------------------------------------------- Outfall1 OUTFALL 0.00 0.00 96.00 0 00:00 0.00 Pond_2 STORAGE 0.06 6.73 110.73 0 01:05 6.62 Pond_1 STORAGE 0.53 7.28 108.28 0 02:29 7.28 Pond_3 STORAGE 0.03 4.55 109.55 0 00:49 4.40 OS_P1 STORAGE 2.01 4.12 111.12 0 01:03 4.10 OS_P2 STORAGE 2.09 10.00 117.00 0 01:27 9.99 Pond_4 STORAGE 0.11 3.38 108.38 0 01:32 3.38 ******************* Node Inflow Summary ******************* ------------------------------------------------------------------------------------------------- Maximum Maximum Lateral Total Flow Lateral Total Time of Max Inflow Inflow Balance Inflow Inflow Occurrence Volume Volume Error Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Percent SWMM 5 Page 3 ------------------------------------------------------------------------------------------------- Outfall1 OUTFALL 0.00 55.95 0 01:41 0 11.3 0.000 Pond_2 STORAGE 78.99 182.56 0 00:41 1.29 4.6 0.028 Pond_1 STORAGE 78.88 275.66 0 00:41 1.51 10.4 0.037 Pond_3 STORAGE 115.88 115.88 0 00:40 1.46 1.46 0.062 OS_P1 STORAGE 101.31 101.31 0 00:40 1.95 1.95 0.128 OS_P2 STORAGE 144.17 144.17 0 00:40 4.36 4.36 0.023 Pond_4 STORAGE 59.34 59.34 0 00:40 0.888 0.888 0.078 ********************* Node Flooding Summary ********************* Flooding refers to all water that overflows a node, whether it ponds or not. -------------------------------------------------------------------------- Total Maximum Maximum Time of Max Flood Ponded Hours Rate Occurrence Volume Volume Node Flooded CFS days hr:min 10^6 gal 1000 ft3 -------------------------------------------------------------------------- OS_P2 0.20 14.13 0 01:16 0.036 0.000 ********************** Storage Volume Summary ********************** -------------------------------------------------------------------------------------------------- Average Avg Evap Exfil Maximum Max Time of Max Maximum Volume Pcnt Pcnt Pcnt Volume Pcnt Occurrence Outflow Storage Unit 1000 ft3 Full Loss Loss 1000 ft3 Full days hr:min CFS -------------------------------------------------------------------------------------------------- Pond_2 0.484 0 0 0 68.226 50 0 01:05 120.00 Pond_1 60.443 3 0 0 1116.165 64 0 02:29 44.70 Pond_3 0.155 0 0 0 34.940 26 0 00:49 60.00 OS_P1 13.595 4 0 0 56.598 17 0 01:03 51.00 OS_P2 4.073 4 0 0 107.000 100 0 01:15 82.00 Pond_4 1.424 0 0 0 62.025 9 0 01:32 11.30 SWMM 5 Page 4 *********************** Outfall Loading Summary *********************** ----------------------------------------------------------- Flow Avg Max Total Freq Flow Flow Volume Outfall Node Pcnt CFS CFS 10^6 gal ----------------------------------------------------------- Outfall1 19.35 17.92 55.95 11.299 ----------------------------------------------------------- System 19.35 17.92 55.95 11.299 ******************** Link Flow Summary ******************** ----------------------------------------------------------------------------- Maximum Time of Max Maximum Max/ Max/ |Flow| Occurrence |Veloc| Full Full Link Type CFS days hr:min ft/sec Flow Depth ----------------------------------------------------------------------------- P2_Out DUMMY 120.00 0 00:42 P1_Out DUMMY 44.70 0 01:41 P3_Out DUMMY 60.00 0 00:42 P4_Out DUMMY 11.30 0 01:32 OS_P1_Out DUMMY 51.00 0 00:41 OS_P2_Out DUMMY 82.00 0 00:39 ************************* Conduit Surcharge Summary ************************* No conduits were surcharged. Analysis begun on: Tue Oct 08 15:38:13 2019 Analysis ended on: Tue Oct 08 15:38:13 2019 Total elapsed time: < 1 sec SWMM 5 Page 5 SWMM 5 Page 6 Node Pond_1 Volume (ft3) Elapsed Time (hours) 0 20 40 60 80 100 120 140 Volume (ft3) 1200000.0 1000000.0 800000.0 600000.0 400000.0 200000.0 0.0 SWMM 5 Page 1 Node Pond_2 Volume (ft3) Elapsed Time (hours) 0 20 40 60 80 100 120 140 Volume (ft3) 70000.0 60000.0 50000.0 40000.0 30000.0 20000.0 10000.0 0.0 SWMM 5 Page 1 Node Pond_3 Volume (ft3) Elapsed Time (hours) 0 20 40 60 80 100 120 140 Volume (ft3) 35000.0 30000.0 25000.0 20000.0 15000.0 10000.0 5000.0 0.0 SWMM 5 Page 1 Node Pond_4 Volume (ft3) Elapsed Time (hours) 0 20 40 60 80 100 120 140 Volume (ft3) 70000.0 60000.0 50000.0 40000.0 30000.0 20000.0 10000.0 0.0 SWMM 5 Page 1 APPENDIX D Erosion Control Report PSD Middle School High School #2 Preliminary Erosion Control Report A comprehensive Erosion and Sediment Control Plan (along with associated details) will be included with the final construction drawings. It should be noted, however, that any such Erosion and Sediment Control Plan serves only as a general guide to the Contractor. 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 living document, constantly adapting to site conditions and needs. The Contractor shall update the location of BMPs as they are installed, removed or modified in conjunction with construction activities. It is imperative to appropriately reflect the current site conditions at all times. The Erosion and Sediment Control Plan shall address both temporary measures to be implemented during construction, as well as permanent erosion control protection. Best Management Practices from the Volume 3, Chapter 7 – Construction BMPs will be utilized. Measures may include, but are not limited to, silt fencing along the disturbed perimeter, gutter protection in the adjacent roadways and inlet protection at existing and proposed storm inlets. Vehicle tracking control pads, spill containment and clean-up procedures, designated concrete washout areas, dumpsters, and job site restrooms shall also be provided by the Contractor. Grading and Erosion Control Notes can be found on the Utility Plans. The Final Plans will contain a full-size Erosion Control sheet as well as a separate sheet dedicated to Erosion Control Details. In addition to this report and the referenced plan sheets, the Contractor shall be aware of, and adhere to, the applicable requirements outlined in the Development Agreement for the development. Also, the Site Contractor for this project will be required to secure a Stormwater Construction General Permit from the Colorado Department of Public Health and Environment (CDPHE), Water Quality Control Division – Stormwater Program, prior to any earth disturbance activities. Prior to securing said permit, the Site Contractor shall develop a comprehensive StormWater Management Plan (SWMP) pursuant to CDPHE requirements and guidelines. The SWMP will further describe and document the ongoing activities, inspections, and maintenance of construction BMPs. APPENDIX E USDA Soils Information 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 Natural Area, Colorado Resources Conservation Service October 7, 2019 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface.................................................................................................................... 2 How Soil Surveys Are Made..................................................................................5 Soil Map.................................................................................................................. 8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................ 11 Map Unit Descriptions.........................................................................................11 Larimer County Area, Colorado...................................................................... 13 7—Ascalon sandy loam, 0 to 3 percent slopes........................................... 13 40—Garrett loam, 0 to 1 percent slopes..................................................... 14 64—Loveland clay loam, 0 to 1 percent slopes...........................................15 76—Nunn clay loam, wet, 1 to 3 percent slopes......................................... 17 77—Otero sandy loam, 0 to 3 percent slopes............................................. 18 81—Paoli fine sandy loam, 0 to 1 percent slopes....................................... 19 92—Riverwash............................................................................................20 105—Table Mountain loam, 0 to 1 percent slopes...................................... 21 References............................................................................................................24 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 4490500 4490600 4490700 4490800 4490900 4491000 4491100 4491200 4490500 4490600 4490700 4490800 4490900 4491000 4491100 4491200 500400 500500 500600 500700 500800 500900 501000 501100 501200 501300 501400 501500 501600 500400 500500 500600 500700 500800 500900 501000 501100 501200 501300 501400 501500 501600 40° 34' 19'' N 104° 59' 45'' W 40° 34' 19'' N 104° 58' 50'' W 40° 33' 52'' N 104° 59' 45'' W 40° 33' 52'' N 104° 58' 50'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 13N WGS84 0 250 500 1000 1500 Feet 0 50 100 200 300 Meters Map Scale: 1:5,890 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 7 Ascalon sandy loam, 0 to 3 percent slopes 0.1 0.1% 40 Garrett loam, 0 to 1 percent slopes 1.2 1.2% 64 Loveland clay loam, 0 to 1 percent slopes 68.1 71.8% 76 Nunn clay loam, wet, 1 to 3 percent slopes 2.6 2.8% 77 Otero sandy loam, 0 to 3 percent slopes 4.3 4.5% 81 Paoli fine sandy loam, 0 to 1 percent slopes 8.9 9.4% 92 Riverwash 3.8 4.0% 105 Table Mountain loam, 0 to 1 percent slopes 6.0 6.3% Totals for Area of Interest 94.9 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a Custom Soil Resource Report 11 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. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Larimer County Area, Colorado 7—Ascalon sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2swl3 Elevation: 3,870 to 5,960 feet Mean annual precipitation: 12 to 16 inches Mean annual air temperature: 46 to 57 degrees F Frost-free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Ascalon and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Ascalon Setting Landform: Interfluves Landform position (two-dimensional): Summit Down-slope shape: Linear Across-slope shape: Linear Parent material: Wind-reworked alluvium and/or calcareous sandy eolian deposits Typical profile Ap - 0 to 6 inches: sandy loam Bt1 - 6 to 12 inches: sandy clay loam Bt2 - 12 to 19 inches: sandy clay loam Bk - 19 to 35 inches: sandy clay loam C - 35 to 80 inches: sandy loam 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 Salinity, maximum in profile: Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 1.0 Available water storage in profile: Moderate (about 7.7 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4c Hydrologic Soil Group: B Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No Custom Soil Resource Report 13 Minor Components Olnest Percent of map unit: 10 percent Landform: Interfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No Vona Percent of map unit: 5 percent Landform: Interfluves Landform position (two-dimensional): Summit Down-slope shape: Linear Across-slope shape: Linear Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No 40—Garrett loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpwg Elevation: 5,200 to 6,000 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 Garrett and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Garrett Setting Landform: Fans, terraces Landform position (three-dimensional): Base slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium derived from sandstone and shale Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 39 inches: sandy clay loam, sandy loam H2 - 8 to 39 inches: sandy loam H3 - 39 to 60 inches: Custom Soil Resource Report 14 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 Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 12.9 inches) Interpretive groups Land capability classification (irrigated): 2w Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Ecological site: Overflow (R049XY036CO) Hydric soil rating: No Minor Components Harlan Percent of map unit: 6 percent Hydric soil rating: No Barnum Percent of map unit: 5 percent Hydric soil rating: No Connerton Percent of map unit: 4 percent Hydric soil rating: No 64—Loveland clay loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpx9 Elevation: 4,800 to 5,500 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 Loveland and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Custom Soil Resource Report 15 Description of Loveland Setting Landform: Flood plains, stream terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 15 inches: clay loam H2 - 15 to 32 inches: clay loam, silty clay loam, loam H2 - 15 to 32 inches: very gravelly sand, gravelly sand, gravelly coarse sand H2 - 15 to 32 inches: H3 - 32 to 60 inches: H3 - 32 to 60 inches: H3 - 32 to 60 inches: Properties and qualities Slope: 0 to 1 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Poorly drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.60 in/hr) Depth to water table: About 18 to 36 inches Frequency of flooding: Occasional Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Very slightly saline to slightly saline (2.0 to 4.0 mmhos/cm) Available water storage in profile: Very high (about 16.7 inches) Interpretive groups Land capability classification (irrigated): 3w Land capability classification (nonirrigated): 3w Hydrologic Soil Group: C Hydric soil rating: No Minor Components Aquolls Percent of map unit: 5 percent Landform: Swales Hydric soil rating: Yes Poudre Percent of map unit: 5 percent Hydric soil rating: No Custom Soil Resource Report 16 76—Nunn clay loam, wet, 1 to 3 percent slopes Map Unit Setting National map unit symbol: jpxq Elevation: 4,800 to 5,600 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 Nunn, wet, and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Nunn, Wet Setting Landform: Alluvial fans, stream terraces Landform position (three-dimensional): Base slope, tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 10 inches: clay loam H2 - 10 to 47 inches: clay loam, clay H2 - 10 to 47 inches: clay loam, loam, gravelly sandy loam H3 - 47 to 60 inches: H3 - 47 to 60 inches: H3 - 47 to 60 inches: Properties and qualities Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat poorly drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table: About 24 to 36 inches Frequency of flooding: Rare Frequency of ponding: None Calcium carbonate, maximum in profile: 10 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 19.8 inches) Interpretive groups Land capability classification (irrigated): 2w Land capability classification (nonirrigated): 3s Custom Soil Resource Report 17 Hydrologic Soil Group: C Hydric soil rating: No Minor Components Heldt Percent of map unit: 6 percent Hydric soil rating: No Dacono Percent of map unit: 3 percent Hydric soil rating: No Mollic halaquepts Percent of map unit: 1 percent Landform: Swales Hydric soil rating: Yes 77—Otero sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: jpxr Elevation: 4,800 to 5,600 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 Otero and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Otero Setting Landform: Fans Landform position (three-dimensional): Side slope, base slope Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium and/or eolian deposits Typical profile H1 - 0 to 17 inches: sandy loam H2 - 17 to 60 inches: sandy loam, fine sandy loam, loamy very fine sand H2 - 17 to 60 inches: H2 - 17 to 60 inches: Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat excessively drained Custom Soil Resource Report 18 Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): High (2.00 to 6.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 5 percent Salinity, maximum in profile: Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm) Available water storage in profile: Very high (about 14.9 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: A Ecological site: Sandy Plains (R067BY024CO) Hydric soil rating: No Minor Components Kim Percent of map unit: 8 percent Hydric soil rating: No Ascalon Percent of map unit: 6 percent Hydric soil rating: No Nelson Percent of map unit: 1 percent Hydric soil rating: No 81—Paoli fine sandy loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpxx Elevation: 4,800 to 5,600 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 Paoli and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Paoli Setting Landform: Stream terraces Landform position (three-dimensional): Tread Custom Soil Resource Report 19 Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 30 inches: fine sandy loam H2 - 30 to 60 inches: fine sandy loam, sandy loam, loamy sand H2 - 30 to 60 inches: H2 - 30 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: Very low Capacity of the most limiting layer to transmit water (Ksat): High (2.00 to 6.00 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 15 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Very high (about 16.5 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: A Ecological site: Overflow (R067BY036CO) Hydric soil rating: No Minor Components Caruso Percent of map unit: 6 percent Hydric soil rating: No Table mountain Percent of map unit: 6 percent Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit: 3 percent Landform: Terraces Hydric soil rating: Yes 92—Riverwash Map Unit Setting National map unit symbol: jpy9 Elevation: 4,000 to 8,500 feet Custom Soil Resource Report 20 Mean annual precipitation: 12 to 20 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 75 to 150 days Farmland classification: Not prime farmland Map Unit Composition Riverwash: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Riverwash Setting Landform: Outwash terraces, overflow stream channels, flood plains Down-slope shape: Linear Across-slope shape: Linear Parent material: Sandy and gravelly alluvium Typical profile H1 - 0 to 6 inches: very gravelly sand H2 - 6 to 60 inches: stratified very gravelly sand to clay Properties and qualities Slope: 0 to 3 percent Natural drainage class: Somewhat excessively drained Runoff class: Negligible Capacity of the most limiting layer to transmit water (Ksat): High to very high (6.00 to 20.00 in/hr) Frequency of flooding: Frequent Calcium carbonate, maximum in profile: 5 percent Salinity, maximum in profile: Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 2.0 Available water storage in profile: Very low (about 2.3 inches) Interpretive groups Land capability classification (irrigated): 6w Land capability classification (nonirrigated): 7w Hydrologic Soil Group: A Hydric soil rating: Yes 105—Table Mountain loam, 0 to 1 percent slopes Map Unit Setting National map unit symbol: jpty Elevation: 4,800 to 5,600 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 Table mountain and similar soils: 85 percent Minor components: 15 percent Custom Soil Resource Report 21 Estimates are based on observations, descriptions, and transects of the mapunit. Description of Table Mountain Setting Landform: Flood plains, stream terraces Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Alluvium Typical profile H1 - 0 to 36 inches: loam H2 - 36 to 60 inches: loam, clay loam, silt loam H2 - 36 to 60 inches: H2 - 36 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: 15 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 5.0 Available water storage in profile: Very high (about 18.0 inches) Interpretive groups Land capability classification (irrigated): 1 Land capability classification (nonirrigated): 3c Hydrologic Soil Group: B Ecological site: Overflow (R049XY036CO) Hydric soil rating: No Minor Components Caruso Percent of map unit: 7 percent Hydric soil rating: No Fluvaquentic haplustolls Percent of map unit: 4 percent Landform: Terraces Hydric soil rating: Yes Paoli Percent of map unit: 4 percent Hydric soil rating: No Custom Soil Resource Report 22 Custom Soil Resource Report 23 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 24 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 25 MAP POCKET Drainage Exhibit MH MH MH MH MH MH MH MH MH MH MH MH MH MH MH S W W S S S S S S W W W W S S S S W W W W W W W S S S S S S S S S S S S S S S S S S S S S S S S S S S W W W W W W W W W W W W W W W W W W W W W W W W W W W W S S S S S S S S S W M H MH MH MH MH MH MH MH MH MH MH W W W W W MH G 1 2 3 4 5 4 3 2 1 0 G G 1 0 2 0 3 0 4 0 5 0 4 0 3 0 2 0 1 0 G 0 0 0 0 0 0 0 0 G 1 2 3 4 5 4 3 2 1 0 G G 1 0 2 0 3 0 4 0 5 0 4 0 3 0 2 0 1 0 G 0 0 0 0 0 0 0 0 / / / / / / / / 30' BOXELDER SANITATION DISTRICT UTILITY EASEMENT / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / X X X X P P EO EO EO EO EO EO EO EO EO EO EO EO ET ET EP EP EP ET EV EV ET ET LT LT LT LT LT LT LT LT LT LT LT LT LT LT LT LT SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP SP TPED TPED TPED TPED D / / / / / / / / / / / / / / / / X X X X F E S F E S F E S F MH .O. C.O. VAULT F.O. VAULT F.O. CONTROL IRR TELE TELE F.O. F.O. F.O. CONTROL IRR CONTROL IRR CONTROL IRR CONTROL IRR F.O. F.O. F.O. F.O. F.O. F.O. F.O. F.O. F.O. MH T F.O. CONTROL IRR VAULT F.O. VAULT F.O. T O. F.O. T T X X X X OHE OHE OHE OHE OHE OHE / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / OHE OHE OHE W W W W W W W MH / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / X X X X X X X X X X X X T R4 SB2 SB5 SB5A SB15 W W 1 2 3 4 5 6 7 8 9 12 11 10 OS1 3 10 11 12 SB5 SB5A SB15 R3 R2 R1 R3 R2 R1 1 2 6 7 8 9 4 5 OS1 PROSPECT ROAD MAIN STREET PROSPECT ROAD MAIN STREET PROPOSED STORM DRAIN PROPOSED PROPOSED STORM DRAIN STORM DRAIN DESCRIPTION DATE E NGINEER ING N O R T H E RN FORT COLLINS: 301 North Howes Street, Suite 100, 80521 GREELEY: 820 8th Street, 80631 970.221.4158 northernengineering.com A of 48 SHEET INFORMATION PROJECT INFORMATION PROJECT PHASE SEAL ARCHITECT ISSUE DATE: PROJECT #: CONSULTANT T - 970.484.0117 F - 970.484.0264 315 East Mountain Ave Suite 100 Fort Collins, CO 80524-2913 © 2015 www.rbbarchitects.com ARCHITECTS REVISIONS: 100-024 POUDRE SCHOOL DISTRICT DESIGN DEVELOPMENT - 10/09/19 PROSPECT ROAD & MAIN STREET FORT COLLINS, CO B C D 5 4 3 2 1 Not For Construction PSD MIDDLE SCHOOL HIGH SCHOOL # 2 KEYMAP P P C.O. / / / / / / / / / / / / / / / / / / / / / / / / 5 4 3 2 1 G 4 0 G 1 2 3 G 1 0 2 0 3 0 4 0 5 0 4 0 3 0 2 0 1 0 G 0 0 0 0 0 0 0 0 G 1 2 3 4 5 4 3 2 1 0 G G 1 0 2 0 3 0 4 0 5 0 4 0 3 0 2 0 1 0 G 0 0 0 0 0 0 0 0 / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / / PROSPECT RD MAIN STREET TRIC ( IN FEET ) 0 1 INCH = 200 FEET 200 200 400 600 DRAINAGE EXHIBIT C600 LEGEND: ST ST ST PROPOSED EASEMENT EXISTING RIGHT OF WAY PROPOSED LOT LINE PROPERTY BOUNDARY PROPOSED CURB AND GUTTER PROPOSED SWALE EXISTING CONTOUR PROPOSED CONTOUR PROPOSED STORM INLET PROPOSED STORM SEWER EXISTING STORM SEWER PROPOSED RIGHT OF WAY A DRAINAGE BASIN LABEL DRAINAGE BASIN BOUNDARY B2 1.45 ac DESIGN POINT FLOW ARROWS 1. EXISTING UNDERGROUND AND OVERHEAD PUBLIC AND PRIVATE UTILITIES AS SHOWN ARE INDICATED ACCORDING TO THE BEST INFORMATION AVAILABLE TO THE ENGINEER. THE ENGINEER DOES NOT GUARANTEE THE ACCURACY OF SUCH INFORMATION. EXISTING UTILITY MAINS AND SERVICES MAY NOT BE STRAIGHT LINES OR AS INDICATED ON THESE DRAWINGS. THE CONTRACTOR SHALL BE RESPONSIBLE TO CALL ALL UTILITY COMPANIES (PUBLIC AND PRIVATE) PRIOR TO ANY CONSTRUCTION TO VERIFY EXACT UTILITY LOCATIONS. 2. REFER TO THE "PRELIMNARY DRAINAGE REPORT FOR PSD MIDDLE SCHOOL HIGH SCHOOL #2 DATED OCTOBER 9, 2019" BY NORTHERN ENGINEERING FOR ADDITIONAL INFORMATION. 3. ALL PROJECT DATA IS ON THE CITY OF FORT COLLINS VERTICAL DATUM; NAVD88. SEE COVER SHEET FOR BENCHMARK REFERENCES. 4. REFER TO THE PLAT FOR LOT AREAS, TRACT SIZES, EASEMENTS, LOT DIMENSIONS, UTILITY EASEMENTS, OTHER EASEMENTS, AND OTHER SURVEY INFORMATION. NOTES: BASIN DESIGNATION BASIN AREA (AC) PROPOSED SWALE 1 1 FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION DRAINAGE SUMMARY TABLE DESIGN POINT BASIN ID TOTAL AREA (acres) C2 C100 2-yr Tc (min) 100-yr Tc (min) Q2 (cfs) Q100 (cfs) 1 1 6.96 0.55 0.69 14.9 14.9 7.3 31.7 2 2 6.05 0.43 0.53 10.7 10.7 5.6 24.3 3 3 10.01 0.67 0.84 14.0 14.0 12.9 56.2 4 4 9.80 0.51 0.64 13.5 13.5 9.7 42.5 5 5 4.22 0.43 0.53 14.4 14.4 3.4 15.0 6 6 9.15 0.36 0.45 10.6 10.6 7.2 31.4 7 7 5.92 0.40 0.51 10.5 10.5 5.3 23.1 8 8 2.59 0.45 0.57 11.9 11.9 2.5 10.7 9 9 3.47 0.33 0.42 12.7 12.7 2.3 10.2 10 10 8.35 0.64 0.80 9.0 9.0 12.6 55.0 11 11 5.89 0.80 1.00 10.3 10.3 10.4 45.2 12 12 13.70 0.29 0.36 10.8 10.8 8.5 37.0 R1 R1 4.03 0.45 0.56 9.8 9.8 4.0 17.7 R2 R2 2.57 0.49 0.61 9.6 9.6 2.8 12.3 R3 R3 2.13 0.48 0.60 9.4 9.4 2.4 10.3 OS1 OS1 13.80 0.78 0.98 15.3 15.3 20.2 88.0 NORTH CALL UTILITY NOTIFICATION CENTER OF COLORADO Know what'sbelow. Call before you dig. R 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 10 55 0.87 1.48 3.03 22 1.53 2.61 5.32 56 0.86 1.47 2.99 23 1.49 2.55 5.20 57 0.85 1.45 2.96 24 1.46 2.49 5.09 58 0.84 1.43 2.92 25 1.43 2.44 4.98 59 0.83 1.42 2.89 26 1.4 2.39 4.87 60 0.82 1.4 2.86 27 1.37 2.34 4.78 65 0.78 1.32 2.71 28 1.34 2.29 4.69 70 0.73 1.25 2.59 29 1.32 2.25 4.60 75 0.70 1.19 2.48 30 1.30 2.21 4.52 80 0.66 1.14 2.38 31 1.27 2.16 4.42 85 0.64 1.09 2.29 32 1.24 2.12 4.33 90 0.61 1.05 2.21 33 1.22 2.08 4.24 95 0.58 1.01 2.13 34 1.19 2.04 4.16 100 0.56 0.97 2.06 35 1.17 2.00 4.08 105 0.54 0.94 2.00 36 1.15 1.96 4.01 110 0.52 0.91 1.94 37 1.16 1.93 3.93 115 0.51 0.88 1.88 38 1.11 1.89 3.87 120 0.49 0.86 1.84 Q  C f  C  i  A  Tt (min) 2-yr Tc (min) 10-yr Tc (min) 100-yr Tc (min) 1 1 No 0.25 0.25 0.31 106 2.00% 13.0 13.0 12.0 779 1.00% 2.00 6.5 0 0.00% N/A N/A 14.9 14.9 14.9 2 2 No 0.25 0.25 0.31 124 2.00% 14.0 14.0 13.0 0 0.00% N/A N/A 0 0.00% N/A N/A 10.7 10.7 10.7 3 3 No 0.25 0.25 0.31 82 3.40% 9.6 9.6 8.9 643 1.00% 2.00 5.4 0 0.00% N/A N/A 14.0 14.0 14.0 4 4 No 0.25 0.25 0.31 118 2.00% 13.7 13.7 12.7 520 1.00% 2.00 4.3 0 0.00% N/A N/A 13.5 13.5 13.5 5 5 No 0.25 0.25 0.31 120 2.00% 13.8 13.8 12.8 680 1.00% 2.00 5.7 0 0.00% N/A N/A 14.4 14.4 14.4 6 6 No 0.25 0.25 0.31 105 2.00% 12.9 12.9 12.0 0 0.00% N/A N/A 0 0.00% N/A N/A 10.6 10.6 10.6 7 7 No 0.25 0.25 0.31 87 2.00% 11.8 11.8 10.9 0 0.00% N/A N/A 0 0.00% N/A N/A 10.5 10.5 10.5 8 8 No 0.25 0.25 0.31 64 2.00% 10.1 10.1 9.4 280 1.00% 2.00 2.3 0 0.00% N/A N/A 11.9 11.9 11.9 9 9 No 0.25 0.25 0.31 75 2.00% 10.9 10.9 10.1 418 1.00% 2.00 3.5 0 0.00% N/A N/A 12.7 12.7 12.7 10 10 No 0.25 0.25 0.31 22 2.00% 5.9 5.9 5.5 364 1.00% 2.00 3.0 0 0.00% N/A N/A 9.0 9.0 9.0 11 11 No 0.25 0.25 0.31 35 2.00% 7.5 7.5 6.9 340 1.00% 2.00 2.8 0 0.00% N/A N/A 10.3 10.3 10.3 12 12 No 0.25 0.25 0.31 140 2.00% 14.9 14.9 13.8 0 0.00% N/A N/A 0 0.00% N/A N/A 10.8 10.8 10.8 R1 R1 No 0.25 0.25 0.31 60 2.00% 9.8 9.8 9.1 0 0.00% N/A N/A 0 0.00% N/A N/A 9.8 9.8 9.8 R2 R2 No 0.25 0.25 0.31 58 2.00% 9.6 9.6 8.9 0 0.00% N/A N/A 0 0.00% N/A N/A 9.6 9.6 9.6 R3 R3 No 0.25 0.25 0.31 55 2.00% 9.4 9.4 8.7 0 0.00% N/A N/A 0 0.00% N/A N/A 9.4 9.4 9.4 OS1 OS1 No 0.25 0.25 0.31 110 2.00% 13.2 13.2 12.3 850 1.00% 2.00 7.1 0 0.00% N/A N/A 15.3 15.3 15.3 TIME OF CONCENTRATION COMPUTATIONS Gutter Flow Swale Flow Design Point Basin Overland Flow ATC October 7, 2019 Time of Concentration (Equation RO-4)   3 1 1 . 87 1 . 1 * S C Cf L Ti   10 363852 8.35 4.18 0.50 0.00 0.00 3.68 0.64 0.64 0.80 55% 11 256437 5.89 4.24 0.35 0.00 0.00 1.30 0.80 0.80 1.00 77% 12 596989 13.70 0.41 0.27 0.00 0.00 13.02 0.29 0.29 0.36 5% R1 175350 4.03 1.01 0.12 0.00 0.00 2.90 0.45 0.45 0.56 28% R2 111971 2.57 0.80 0.08 0.00 0.00 1.70 0.49 0.49 0.61 34% R3 92745 2.13 0.64 0.06 0.00 0.00 1.43 0.48 0.48 0.60 33% OS1 601124 13.80 6.90 0.83 2.76 0.00 3.31 0.78 0.78 0.98 73% COMPOSITE % IMPERVIOUSNESS AND RUNOFF COEFFICIENT CALCULATIONS Runoff Coefficients are taken from the City of Fort Collins Storm Drainage Design Criteria and Construction Standards, Table3.2-2. % Impervious taken from UDFCD USDCM, Volume I. NOTE: Impervious areas have been estimated for preliminary design and planning purposes and are subject to change at Final Design. 10-year Cf = 1.00 October 7, 2019