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HomeMy WebLinkAboutDrainage Reports - 03/13/2018I I L 11 .1 1] I A This Drainage Report Is consciously provided as a PDF. t Please consider the environment before printing this document in Its entirety. When a hard copy Is absolutely necessary, we recommend double -aided printing. City of F rt Collins Approved PI ns Approved b Date; /3 14e FINAL DRAINAGE AND EROSION CONTROL REPORT FOR UNION ON ELIZABETH Fort Collins, Colorado Prepared for: Plum Owner Ft Collins CO LLC 999 South Shady Grove Road, Suite 600 Memphis, TN 38120 Prepared by: ■� I NORTHERN ENGINEERING 301 N. Howes, Suite 100 Fort Collins, Colorado 80521 Phone: 970.221.4158 Fax: 970.221.4159 www.iwdhemmWineedng.com Project Number: 1252-005 ' NorthernEnolneerina.corn H 970.221.4158 NORTHERN ' ENGINEERING ' March 9, 2018 City of Fort Collins 1 Stormwater Utility 700 Wood Street Fort Collins, Colorado 80521 RE: Final Drainage and Erosion Control Report for UNION ON ELIZABETH ' Dear Staff: 1 I I I I Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your review. This report accompanies the Final Plan submittal for the proposed "Union on Elizabeth" development. This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM), and serves to document the stormwater impacts associated with the proposed project. We understand that review by the City is to assure general compliance with standardized criteria contained in the FCSCM. If you should have any questions as you review this report, please feel free to contact us. Sincerely, NORTHERN ENGINEERING SERVICES, INC. ama. Aaron Cvar, PhD, PE Senior Project Engineer FORT COLLINS: 301 North Howes Street, Suite 100, 80521 1 970.221.4158 GREELEY: 820 8 m Street, 80631 1970.395.98801 WEB: www.northernengineedng.com ' ■y INORTHERN ENGINEERING Union on Elizabeth ' 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....................................................................... 6 ' A. Major Basin Description....................................................................................................................6 B. Sub -Basin Description.......................................................................................................................6 ' III. DRAINAGE DESIGN CRITERIA................................................................................... 7 A. Regulations........................................................................................................................................7 IC. B. Four Step Process.............................................................................................................................. Development Criteria Reference and Constraints............................................................................7 7 D. Hydrological Criteria.........................................................................................................................8 ' E. Hydraulic Criteria..............................................................................................................................8 F. Modifications of Criteria................................................................................................................... 8 eIV. DRAINAGE FACILITY DESIGN.................................................................................... 9 A. General Concept...............................................................................................................................9 ' B. Specific Details................................................................................................................................10 V. CONCLUSIONS......................................................................................................11 ' A. Compliance with Standards............................................................................................................11 B. Drainage Concept............................................................................................................................11 ' APPENDICES: APPENDIX A — Hydrologic Computations, Historic Drainage Exhibit APPENDIX B - USDA Soils Information ' APPENDIX C — Hydraulic Computations APPENDIX D — Water Quality Calculations, LID Information APPENDIX E — Detention Calculations APPENDIX F — Erosion Control Report APPENDIX G — Current Effective FIRM Panel APPENDIX H — Approved Stormater Variance Application ' LIST OF FIGURES: Figure 1 — Aerial Photograph................................................................................................ 2 ' Figure 2— Proposed Site Plan................................................................................................ Figure 3 — Existing Floodplains............................................................................................. 3 4 MAP POCKET: Proposed Drainage Exhibit Floodplain Exhibit Final Drainage Report NORTHERN ENGINEERING Union on Elizabeth 1 1 1 1 I. GENERAL LOCATION AND DESCRIPTION A. Location 1. Vicinity Map t v NORTH LOCATION 2. The project site is located in the northeast quarter of Section 15, Township 7 North, Range 69 West of the 61"Principal Meridian, City of Fort Collins, County of Larimer, State of Colorado. 3. The project site is located west of the intersection of South Shields St. and West Elizabeth Street. 4. The project site lies within the Old Town Master Drainage Basin. Per the Old Town Master Drainage Plan, onsite detention is required. Onsite detention is required for the runoff volume difference between the 100 year developed inflow rate and the 2 year historic release rate. 5. LID water quality treatment will be provided on site, as described in further detail below. Final Drainage Report 1 ' ■� NORTHERN ENGINEERING Union on Elizabeth C] I 1 1 1 I J 1 6. As this is an infill site, much of the area surrounding the site is fully developed. 7. Offsite flows enter the site from the north and west. We have accounted for these offsite flows and will safely convey 100-year offsite flows through the site and discharge flows into the adjacent W. Elizabeth Street Right of Way. Offsite flows will be treated as a "pass -through" design and will not receive water quality treatment or detention. We have defined two offsite basins as shown in the Historic Drainage Exhibit provided in Appendix A. Further discussion of these basins and flow quantities are provided below. B. Description of Property 1. The development area is roughly 2.2 net acres. Figure 1 — Aerial Photograph ' 2. The subject property is currently composed of existing buildings, and landscaped areas. Existing ground slopes are mild to moderate (i.e., 1 - 3±%) through the interior of the property. General topography slopes from northwest to southeast. 1 3. According to the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Survey website: hftp://websoilsurvey.nres.usda.gov/app/WebSoilSurvey.aspx, the site consists of Nunn Clay Loam, which falls into Hydrologic Soil Group C. 4. The proposed project site plan is composed of the development of a student housing development and amenities. Associated site work, water, and sewer lines will be constructed with the development. Onsite water quality treatment is proposed and will consist of several features which are discussed in Section IV, below. Final Drainage Report 2 ■� INORTHERN ENGINEERING on Elizabeth F— . Ku NORTH Figure 2— Proposed Site Plan 5. There are no known irrigation laterals crossing the site. 6. The proposed land use is mixed -use. Final Drainage Report 3 ' (NORTHERN ENGINEERING Union on Elizabeth I� 1 1 I C. F000dplain 1. The project site is not encroached by any FEMA 100-year floodplain, please see Appendix G for a copy of FIRM Map Number 08069CO978G (Revised 5/2/2012). However, the City -designated 100-year flood fringe of W. Elizabeth does encroach along the southern border of the site. Additionally, the project site is affected by the CSU Underpass CLOMR, which, at the direction of City Stormwater Staff, is to be considered best available data. We have obtained the data from this CLOMR, and have utilized the data for establishing base (100-year) flood elevations through the site. Figure 3 —Area F000dplain Mapping (9 NORTH 2. A minimum of 18-inches of freeboard will be provided from base (100-year) flood elevation (BFE) in adjacent Right of Way. This freeboard level will be applied to either the design of finished floor elevations, or the minimum level of flood proofing measures. 3. The base (100-year) flood elevation in the vicinity of the west building is 5029.30 (NAVD 88), which set the flood elevation for the entire site. This flood elevation was interpolated at the upstream (southwest) corner of the proposed west building. Please see Table 1 and Figure 1, below. Final Drainage Report 4 ' (NORTHERN ENGINEERING on Elizabeth 1 I ' MINIMUM FINISHED FLOOR ELEVATION (FFE) - C (FFE VARIES, SEE PLAN) 1 BASE FLOOD ELEVATION ( - A v TABLE 1— West Building Flood Summary Table MIXED -USE BUILDING SUMMARY - WEST BUILDING ELEV. DESIGNATION PROJECT ELEV. (NAVD 88) A 5029.30 FT B 5030.80 FT C 5030.80 FT REGULATORY FLOOD PROTECTION 5030.80 FT ELEVATION FIGURE 1 — Foundation Detail -1 MINIMUM HVAC EQUIPMENT ELEVATION = B 78* MIN. BASE FLOOD ELEVATION fl 4. The vertical datum utilized for site survey work is the City of Fort Collins Benchmark #20-97 (Elevation=5050.15; NAVD 88). 5. It is noted that some of the surrounding developments have used the NGVD 29 (unadjusted) datum. The conversion from NAVD 88 to NGVD 29 (unadjusted) datum is-3.18-ft. 6. Foundation for the retaiVresidential structures will be a combination of slab on grade and a basement foundation. 7. A floodplain use permit will be required for each structure and each site construction element in the floodplain. The floodplain use permit for each building will be approved at the time of building permit application. 8. Critical Facilities are not allowed in the floodplain. There will be no Critical Facilities in the floodplain associated with this project. 9. An elevation certificate will be completed before the Certificate of Occupancy (C.O.) is issued. Final Drainage Report 5 ■QUI INORTHERN ENGINEERING Union on Elizabeth 11. DRAINAGE BASINS AND SUB -BASINS A. Major Basin Description 1. The project site lies within the Old Town Master Drainage Basin. Per the Old Town Master Drainage Plan, onsite detention is required. Onsite detention is required for the runoff volume difference between the 100-year developed inflow rate and the 2-year historic release rate. B. Sub -Basin Description 1. The subject property historically drains overland from the northwest to the southeast. Runoff from the majority of the site has historically been collected in the adjacent W. Elizabeth Street. 2. A more detailed description of the project drainage patterns is provided below. Final Drainage Report 6 'INORTHERN EN RTHEIN6 Union on Elizabeth III. DRAINAGE DESIGN CRITERIA ' A. Regulations There are no optional provisions outside of the FCSCM proposed with the proposed project. 1 B. Four Step Process The overall stormwater management strategy employed with the proposed project utilizes "Four the 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: Paver System with StormTech Chambers ' Sand Filter 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 1 additional BMPs and water quality. The majority of stormwater runoff from the site will ultimately be intercepted and treated using 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: m A portion of the site will be treated via a paver system with StormTech chambers, providing filtration of suspended solids. M The upper level of the proposed parking garage will be treated via a sand filter provided in the lower level of the structure. 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. Final Drainage Report 7 1 .V (NORTHERN ENGINEERING Union on Elizabeth Elevations of existing downstream facilities that the subject property will release to will be maintained. 1 Existing flows from the north and west will need to be safely conveyed through the proposed site. 1 D. Hydrological Criteria 1. The City of Fort Collins Rainfall Intensity -Duration -Frequency Curves, as depicted in Figure RA-16 of the FCSCM, serve as the source for all hydrologic computations associated with the proposed development. Tabulated data contained in Table RA-7 1 has been utilized for Rational Method runoff calculations. 2. The Rational Method has been employed to compute stormwater runoff utilizing 1 coefficients contained in Tables RO-11 and RO-12 of the FCSCM. 3. Three separate design storms have been utilized to address distinct drainage I scenarios. A fourth design storm has also been computed for comparison purposes. The first design storm considered is the 801' percentile rain event, which has been employed to design the projecrs water quality features. The second event analyzed is 1 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 discussed above, the subject property is located in a 100-year floodplain. The proposed project does not propose to modify any natural drainageways. 1 F. Modifications of Criteria 1 I I 1 1 1. The proposed development is not requesting any modifications to criteria at this time. 1 Final Drainage Report 8 ■� (NORTHERN ENGINEERING Union on Elizabeth 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 treatment will be provided using a combination of a paver system, StormTech chambers, and a sand filter within the parking structure, as discussed further below. j 3. Drainage patterns anticipated for drainage basins shown in the Drainage Exhibit are described below. ' Basin 1 Basin 1 is primarily composed of landscaped areas and an alleyway. This basin will drain via alleyway curb and gutter into a curb chase, which will direct runoff into W. Elizabeth Street. Runoff from this basin will not be detained; therefore, the overall site release rate will reduced to compensate for this undetained release. Basins 2a, 2b. 2c & 3 ' Basins 2a, 2b, 2c and 3 are composed primarily of rooftop and parking garage areas, as well as the courtyard paseo. These basins will generally drain via internal piping systems within the proposed buildings or via surface conveyance. Runoff from Basin ' 2a and 2c will be treated by isolator rows within the StormTech system and detained within the overall StormTech chamber system underneath the proposed paver system. Runoff from Basin 2b will be treated by the paver system and detained within the I aggregate subbase and StormTech chambers. Runoff from Basin 3 will be detained and will receive LID treatment within the sand filter in the concrete vault, as discussed further below. The proposed concrete vault in Basin 3 will release into a storm line system which will outfall to the adjacent north curb and gutter of W. Elizabeth Street. The paver subdrain system will also outfall to this storm line system and be conveyed to the adjacent north curb and gutter of W. Elizabeth Street. 1 Basin 4 Basin 4 is composed of landscaped areas and an access drive. This basin will ' generally drain via swale flow to a curb chase into W. Elizabeth Street. Runoff from this basin will not be detained; therefore, the overall site release rate will be reduced to compensate for this undetained release. Basins OSl and OS2 Basin OS1 is composed of offsite drainage areas to the west of the site. These areas are fully developed with portions of the basin consisting of multi -family development and portions consisting of paved parking areas. An offsite basin exhibit has been provided in Appendix A, as well as peak 100-year discharge calculations. Peak 100- year discharge from this basin will be conveyed in a proposed alley section with pan, and will be safely conveyed south along the site western boundary into the north curb and gutter of W. Elizabeth Street. Basin OS2 consists of the recently developed "Scott Plaza" (Ref. 7). The offsite basin exhibit provided in Appendix A shows the extents of this basin and peak 100-year discharge calculations are also provided in this appendix section. Peak 100-year 1 discharge from this basin will be conveyed south as sheet flow across the proposed paver system within Basin 2 and into the north curb and gutter of W. Elizabeth Street. ' Final Drainage Report 9 (NORTHERN ENGINEERING Union on Elizabeth n [1 I I I I A full-size copy of the Drainage Exhibit can be found in the Map Pocket at the end of this report. B. Specific Details 1. Two onsite detention facilities will be provided within the site. A chamber detention system will be utilized in conjunction with the aggregate subgrade of the paver system proposed within Drainage Basins 2a and 2b. The underlying StormTech chamber system will provide detention as well as LID treatment in the Isolator Row for Basins 2a and 2b. The paver system will serve as LID treatment and provide detetion for Basin 2b. A concrete vault detention system will be provided within the building envelope shown within Drainage Basin 3. 2. Based on calculations provided in Appendix E, the required detention volume for the proposed concrete vault is 0.038 Ac-Ft, with a peak 100-year release rate of 5.20 cfs, which is below the allowable release rate discussed above. 3. Based on calculations provided in Appendix E, the required detention volume for the proposed chamber system within the subgrade of the paver system is 0.069 Ac-Ft, with a peak 100-year release rate of 0.75 cfs 4. Emergency overflow conveyance paths and calculations for both detention facilities is provided in Appendix E. 5. A total combined release rate has been determined for the proposed detention facilities has been set at 6.39 cfs. This release rate has been determined based on the methodology utilized for previous projects in close proximity to the current project (approved Final Drainage Report for "The Retreat at 1200 Plum", Ref. 6; approved Final Drainage Report for "Scott Plaza", Ref. 7). The methodology accounts for impervious area that is allowed to be "grandfathered". There is 1.42 acres of impervious area within the development site which drains to W. Elizabeth Street. A 100-year discharge from this impervious area of 9.84 cfs has been calculated. There is 0.80 acres of pervious area within the development site which also drains to W. Elizabeth Street. A 2-year discharge of 0.36 cfs has been calculated from this pervious area. The sum of "grandfathered" impervious area discharge into W. Elizabeth Street combined with 2-year pervious area discharge is 10.20 cfs, which is considered as the allowable peak release rate for the site. We have subtracted the 100-year undetained discharge computed from Basins 1, and 4 (3.81 cfs total) for an allowable release rate of 10.20-3.81=6.39 cfs. 6. LID features within the site include a StormTech chamber system for Basins 2aand 2c, a paver system in Basin 2b, and a sand filter in Basin 3. Please refer to Appendix C for an LID Exhibit and all pertinent calculations and information. As shown in Appendix C, the proposed LID treatment design exceeds the 75% treatment requirement. 7. Stormwater facility Standard Operating Procedures (SOP) will be provided by the City of Fort Collins in the Development Agreement. Final Drainage Report 10 ' INORTHERN EN IN6 Union on Elizabeth 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 Old Town Master Drainage Basin. ' 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 1. 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. ' 2. The drainage concept for the proposed development is consistent with requirements for the Old Town Master Drainage Basin. H 1 I I I IL References 1. Fort Collins Stormwater Criteria Manual, City of Fort Collins, Colorado, as adopted by Ordinance No. 174, 2011, and referenced in Section 26-500 (c) of the City of Fort Collins Municipal Code. 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. 4. Downtown River District (DTRD) Final Design Report, Ayres Associates, February 2012. 5. Urban Storm Drainage Criteria Manual, Volumes 1-3, Urban Drainage and Flood Control District, Wright -McLaughlin Engineers, Denver, Colorado. 6. Final Drainage and Erosion Control Report for The Retreat at 1200 Plum Northern Engineering, April 22, 2009. 7. Final Drainage and Erosion Control Report for Scott Plaza, Northern Engineering June 10, 2014. Final Drainage Report 11 I APPENDIX A ' Hydrologic Computations, Historic Drainage Exhibit I I I I I I I I I I I I I I� u r I ap yZ 000 000 00 0 C n 6 NO V•�0001 O1� 0 a ornM ^ o m a00oo rnn 00t0� 3° N N O N 0 C c.Y cn Cn 0 010MOc0 0^ O .--i 00 00 M O 0 0 CM LO o Cl .r Q LL O as 0 W C Z Q C y d M tO 00 O1 In O d 0 pyp a c Y ^ 01 It N st CA to M M Ln In N to (1 o 0 om OOOOOO OO O O C.1 tOi �Wpp G7 cS E m yyp V M ^01�N(n Ln 00 0) .4 In lO M In In In Q p c - y 0100 N 01 V N m 000000 00 O O U C07 2 O L (�V6 to m a LL cS E Q;E9v N c Ic". (n 1+) C)o 00000000 co O 0 O C� t9 BO o _O ,Z O Ccj 0 �0000 0 0 !C� C Y Z' .m. d E 00�000 0 0 00 0 �; o00000 00 0 0 � M Q y c m 2 c Y cn 01 M 01 O In 01 0 O In (n .-� Ln N H .. Y Q 0 00000 00 Q y� IC5 vs Ci 0m00o0 0 00 W y o 61616 .; o in0 o C5 o MCA Q� MOo0000 ^rn o m 'cc 000000 00 CD Q.m C N i. 10 2` 0 c m a�v o00000 coo 0 Lnl 0 000000 NO CD ( O • O CJ C; 0 0 0 N O O O W :o € A y N M Q Y CA c0MN Ln In In N O N O C V •� M.. 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Recommended percentage imperviousness values Land Use or Surface Characteristics Percentage Imperviousness N Business: Downtown Areas 95 Suburban Areas 75 Residential: Single-family 2.5 acres or larger 12 0.75 — 2.5 acres 20 0.25 — 0.75 acres 30 0.25 acres or less 45 Apartments 75 Industrial: Light areas 80 Heavy areas 90 Parks, cemeteries 10 Playgrounds 25 Schools 55 Railroad yard areas 50 Undeveloped Areas: Historic flow analysis 2 Greenbelts, agricultural 2 Off -site flow analysis (when land use not defined 45 Streets: Paved 100 Gravel (packed) 40 Drive and walks 90 Roofs 90 Lawns, sandy soil 2 Lawns, clayey soil 2 6-8 Urban Drainage and Flood Control District January 2016 Urban Storm Drainage Criteria Manual Volume 1 I i 1 1 11 1 i 1 1 i i 1 1 1 1 1 W� =We Hz� CD i ZW C C� 1 APPENDIX B USDA Soils Information I 1 I I I I I I 7 J I I 1 I USDA United States Department of Agriculture MRCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Larimer County Area, Colorado August 14, 2017 J 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.nres.usda.govtwps/ portal/nres/main/soils/health/) and certain conservation and engineering ' applications. For more detailed information, contact your local USDA Service Center (hftps://offices.sc.egov.usda.gov/locator/app?agency=nres) or your NRCS State Soil Scientist (http://www.nres.usda.govtwps/portal/nres/detaiVsoils/contactus/? cid=nres142p2_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 I ' 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. 1 I 1 1 1 I 1 Contents ' Preface ........................ ........ .................................................................................... 2 How Soil Surveys Are Made..................................................................................5 ' Soil Map.................................................................................................................. 8 SoilMap................................................................................................................9 Legend................................................................................................................10 MapUnit Legend................................................................................................ 11 ' Map Unit Descriptions.........................................................................................11 Larimer County Area, Colorado......................................................................13 74—Nunn clay loam, 1 to 3 percent slopes.................................................13 76—Nunn clay loam, wet, 1 to 3 percent slopes.........................................14 References............................................................................................................16 1 1 1 1 4 I 1 1 i i 1 11 1 1 1 1 1 1 1 1 i 1 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 landforrn 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 1 Custom Soil Resource Report 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 ' identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. t �II 1 L i 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. I 1 I 1 8 039WbC M WW OC9L6W OZ9L6Vt Ol9l6W OWL6W 06mo 099w" OLM" 099W" MlBm M .8c ,5 o50T k 1 1 O CL 1 O PY N O N ' N tU O O� cn O y 7 U ' M.955 o90T V I M.MbS o50I p Y w pp x 0 a � J c c CL p p z Q — - M.995 e90l 059L6" Ma" Of9le" OZ9L86V OL91" 009LW Owww 089u" OL9Lw 099LeVC wgim m k m m r0 « m U LD $ o, m $ � C m � m � 3 c o m v o L -0y NE v p N m= m E m YE° a r; LD0*= v m c c o N a m O _ M C �E 2 O w �E —;0 0,m oa Om Z ry > m E U W ° E LD N 0 L 3C yO ac I o D Q cLa >o 0 o m T o � = o cm�mE m0 U. �c EdUa � tEm ° L v m a m = a = v on dam=EyrL) aa E > La u= 0) LmuaECL an�-emmm W E i N N y 197 m> N LN p m E a a m Z Em a F2 Q c o m Wa - m Op Mm m m E °L O VE m m_ 9 0) 04mp E �ay m o °' og� Qcmdu oa> mo Ec m oEt1CN y2m Ld o-4 N ei m =a° ° m ° y —t—p ° m E m w E a E 0) av¢m o crn iN o 8E y g N N U N r T 12 v a < T o N a w F m o m V'o tr o L s a W N > 3 o cn ;n o = f a Q A A O v C W/� €� y a C O 0 A A h A m W Jw CL a < N T N y 8 � 'o a 0. � a 'uNi E �, m m a?? o 30 O c $ S N °n a m n n m W O N O a �. LL o m T o 0 we m m �m ,G L C > � m O � C > Y O m Z Q O to O O E O to to G f0 coO N U O U (7 U _c J J rG 0 a fr to co fn O_ w N V 0 IL e e w a Q N t0 Custom Soil Resource Report I 1 Map Unit Legend e m� -, Map Unk Symbol .y _. 74 --T.� Lrle 111�1 1:111)Aao ----®-C� o�1C84 Map Unit Name. Nunn day loam, 1 to 3 percent slopes Q s , Acres In AOI Paercent of A01 2.2 91.9%a 76 Nunn day loam, wet, 1 to 3 percent slopes 0.2 8.1 % Totals for Area of Interest 2A 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The ' delineation of such segments on the.map provides sufficient information for the 11 ICustom Soil Resource Report 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 the map in the precedes unit name map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have that profiles 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. I 1 12 ' 1 Custom Soil Resource Report Larimer County Area, Colorado 1 74—Nunn clay loam, 1 to 3 percent slopes Map Unit Setting National map unit symbol: 2tlpl Elevation: 3,900 to 5,840 feet Mean annual precipitation: 13 to 17 inches Mean annual air temperature: 50 to 54 degrees F I Frost -free period: 135 to 160 days Farmland classification: Prime farmland if irrigated Map Unit Composition Nunn and similar soils: 85 percent Minor components: 15 percent 1 Estimates are based on observations, descriptions, and transacts of the mapunit. Description of Nunn Setting Landform: Terraces Landforrn position (three-dimensional): Tread Down -slope shape: Linear ' Across -slope shape: Linear Parent material: Pleistocene aged alluvium and/or eolian deposits Typical profile Ap - 0 to 9 inches: day loam Bt - 9 to 13 inches: clay loam Btk - 13 to 25 inches: day loam Bk1 - 25 to 38 inches: clay loam Bk2 - 38 to 80 inches: clay loam Properties and qualities ' Slope: 1 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 7 percent Salinity, maximum in profile: Nonsaline to very slightly saline (0.1 to 2.0 mmhos/cm) Sodium adsorption ratio, maximum in profile: 0.5 Available water storage in profile: High (about 9.9 inches) Interpretive groups Land capability classification (irrigated): 2e ' Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: Clayey Plains (R067BY042CO) Hydric soil rating: No 13 Custom Soil Resource Report Minor Components Heldt 1 Percent of map unit. 10 percent Landform: Terraces Landform position (three-dimensional): Tread Down -slope shape: Linear Across -slope shape: Linear Ecological site: Clayey Plains (R067BY042CO) 1 Hydric soil rating. No Satanta Percent of map unit. 5 percent Landform. Terraces Landform position (three-dimensional): Tread Down -slope shape: Linear Across -slope shape: Linear 1 Ecological site: Loamy Plains (R067BY002CO) Hydric soil rating. No 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 1 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 Landfonn 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. iH3 - 47 to 60 inches: 14 ICustom Soil Resource Report 1 H3 - 47 to 60 inches: Properties and qualities Slope: 1 to 3 percent 1 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 I Land capability classification (irrigated): 2w Land capability classfcation (nonirrigated): 3s 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 I i 1 1 15 I 1 1 1 1 1 1 1 i 1 1 1 1 1 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.nres.usda.govtwps/portal/ nres/detail/national/soils/?cid=nres 142p2_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. nres. usda.gov/wps/portal/nres/detail/national/soils/?cid=nres l42p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www. nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nresl42p2_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.nres.usda.gov/wps/portal/nres/detaii/soils/ home/?cid=nres 142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nres.usda.govtwps/portal/nres/ detail/nationalAand use/rangepasture/?cid=steiprdb 1043084 16 Custom Soil Resource Report iUnited States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nres.usda.govtwps/portal/ 1 nres/detail/soils/scientists/?cid=nres142p2_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.nres.usda.gov/wps/portal/nres/detail/national/soils/? cid=nres142p2_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/lntemeVFSE—DOCUMENTS/nrcsl42p2_052290.pdf I 1 I 17 I APPENDIX C 1 Water Quality Computations, LID Information 1 1 1 1 1 i 1 1 [1 I 1 1 1 1 \�\ice \ � \ - m y d d m � dam°' � u > is y > 01 m a � v u a a '^ p E E 6 � L 2 U a d C ry C a � r u G — > LL d E E N � m E f E 9 V�1 E w Go r O E 6 E u L m ` � m v d d _ 0 9 d E E o A > — E m a m U v E E m c u A a N �d > E L M O y d w — o u w b d � E d� $ E uu �+ LL 3 o c d d E = —' LO S �> w H cr - � 3 G A n j 'O NORTHERN ENGINEERING L_J I L 1 I StormTech Chamber Data Chamber Dimensions SC-16OLP SC-310 SC-740 Width (in) 25 34.00 51.00 Length (in) 85.4 85.40 85.40 Height (in) 12 16.00 30.00 Floor Area (so 14.83 20.16 30.25 Chamber Volume (cf) 6.85 14.70 45.90 Chamber/Aggregate Volume (cf) 15.00 31.00 74.90 Chamber Flow Rate Conversion (gpm/sf to cfs) Flow Rate`* 0.35 gpm/sf 1 cf = 7.48052 gal 1 gallon = 0.133681 cf 1 GPM = 0.002228 cfs "Flow rate based on 1/2 of Nov 07 CL., in Figure 17 of UNH Testing Report Chamber Flow Rate SC-160LP I SC-310 SC-740 Flow Rate/chamber (cfs) 0.011S621 0.0157241 0.023586 ' NORTHERN ENGINEERING 1 1 1 I I i I Chamber Volume Calculation I FAA Method Project: Union on Elizabeth Project Location: Fort Collins, Colorado Calculations By: A. Reese Date: February 16, 2018 Pond No.: Paseo ChamberE. Input Variables Results Design Point 2 Design Storm WQ Developed "C" = 1.00 Area (A)= 0.45 acres Max Release Rate = 0.50 cfs Required Detention Volume Quantity Detention 42 ft3 Time Time Ft.Collins WQ Intensity Q100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume (mins) (secs) (in/h0 (Cfs) (ft) (ft) (ft) 5 300 1.43 0.6 192 150 42 10 600 1.11 0.5 298 300 -2 15 900 0.94 0.4 379 450 -71 20 1200 0.81 0.4 435 600 -165 25 1500 0.72 0.3 483 750 -267 30 1800 0.65 0.3 527 900 -374 35 2100 0.59 0.3 1 553 1050 -497 40 2400 0.54 0.2 578 1200 -622 45 2700 0.50 0.2 601 1350 -749 50 3000 0.46 0.2 621 1500 -879 55 3300 0.44 0.2 646 1650 -1004 60 3600 0.41 0.2 664 1800 -1136 65 3900 0.39 0.2 676 1950 -1274 70 4200 0.37 0.2 1 690 2100 -1410 75 4500 0.35 0.2 1 699 2250 -1551 80 4800 0.33 0.1 713 2400 -1687 85 5100 0.32 0.1 723 2550 -1827 90 5400 0.31 0.1 741 2700 -1959 95 5700 0.29 0.1 744 2850 -2106 100 6000 0.28 0.1 756 3000 -2244 105 6300 0.27 0.1 765 3150 -2385 110 6600 0.26 0.1 772 3300 -2528 115 6900 0.3 0.1 792 3450 -2658 120 7200 0.25 0.1 794 3600 -2806 D:lProjects11252-0051DrainagelL/D11252-005 FAA Vault l.xisml WATER QUALITY POND DESIGN CALCULATIONS STORMTECH ISOLATOR ROW Project: 1252-001 By: A. Reese 2/16/2018 REQUIRED STORAGE & OUTLET WORKS: BASIN AREA = 0.455 <— INPUT from impervious talcs BASIN IMPERVIOUSNESS PERCENT = 78.80 <— INPUT from impervious calcs BASIN IMPERVIOUSNESS RATIO = 0.7880 <— CALCULATED WQCV (watershed inches) = 0.321 <— CALCULATED from Figure EDB-2 WQCV (ac-ft) = 0.015 <— CALCULATED from UDFCD DCM V.3 Section 6.5 WQCV (cu-ft) = 636 <— CALCULATED from UDFCD DCM V.3 Section 6.5 II Design Procedure Form: Sand Filter (SF) JD-BMP (Version 3.06, November 2016) Sheet 1 of 2 Designer: A. Reeser Company: Northern Engineering Date: February 13, 2018 Project: The Union on Elizabeth Locabon: Fort Collins, Colorado 1. Basin Storage Volume A) Effective Imperviousness of Tributary Area, I, I, = 90.0 % (100% it and paved and roofed areas upstream of sand fitter) B) Tributary Area's Imperviousness Ratio (i = 1 J100) i = 0,900 C) Water Quality Capture Volume (WQCV) Based on 12-hour Drain Time WQCV = 0.32 watershed inches WQCV= 0.8 - (0.91- i'- 1.19 - i°+ 0.78 - it D) Contributing Watershed Area (including sand fitter area) Area =— 45,115 so ft E) Water Quality Capture Volume (WQCV) Design Volume Vwocv = 1,208 cu It Vwocv = WQCV / 12' Area F) For Watersheds Outside of the Denver Region, Depth of dr = in Average Runoff Producing Stone G) For Watersheds Outside of the Denver Region, Vwocvon R = cu ft Water Quality Capture Volume (WQCV) Design Volume H) User Input of Water Quality Capture Volume (WQCV) Design Volume Vwocvusm = cu ft (Only H a different WQCV Design Volume is desired) 2. Basin Geometry A) WQCV Depth Dv c , = 1.3 ft B) Sand Fitter Side Slopes (Horizontal distance per unit vertical, Z = 0.00 it I ft 4:1 or flatter preferred). Use'()' if sand filter has vertical walls. C) Minimum Fitter Area (Flat Surface Area) Ara, = 508 sq it D) Actual Filter Area Pve,w = 928 sq tt E) Volume Provided VT = 1216 cu ft rChoose One 3. Filter Maternal *t8' (D0T Oars 8 a C Filter Material C)Jthe+ (Explain): I 4. Underdraln System one A) Are underdrains provided'? Fe ES W (-)No B) Underdrain system orifice diameter for 12 hour drain time i) Distance From Lowest Elevation of the Storage y= fi Volume to the Center of the Orifice li) Volume to Drain in 12 Hours V0117= N/A cu ft lii) Orifice Diameter, 318' Minimum Do = in Sand Ftter_U0-BMP_v3.06.xlsm, SF 2/13/2018, 5:26 PM APPENDIX D i Hydraulic Calculations I I I I I 1 I I 7 I I J I SIDEWALK CULVERT CAPACITY CALCULATIONS Channel Report BASIN 1 + BASIN OS1 2YR FLOW=6.54 CFS Hydraflow Express Extension for Autodesk® AuloCAD® Civil 3D® by Autodesk, Inc. Sidewalk Cullvert-Basin 1 Outfall iRectangular Bottom Width (ft) = 2.00 Total Depth (ft) = 0.47 Invert Elev (ft) = 100.00 Slope (%) = 2.00 N-Value = 0.013 'Calculations Compute by: Known Q Known Q (cfs) = 6.54 1 Elev (ft) Section Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (fbs) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Friday, Dec 29 2017 = 0.45 = 6.540 = 0.90 = 7.27 = 2.90 = 0.47 = 2.00 = 1.27 I i.uu 1 100.75 i ' 100.50 i 100.25 ' ' 100.00 44 7-r, 0 .5 1 1.5 2 2.5 3 Reach (ft) Depth (ft) 1.00 0.75 0.50 0.25 0M -0.25 SIDEWALK CULVERT CAPACITY CALCULATIONS CONC.VAULT; ' Channel Report CHAMBER SYSTEM 100-YR COMBINED FLOW=5.95 CFS Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3138 by Autodesk, Inc. Sidewalk Cullvert-ConcNault Outfall Rectangular Bottom Width (ft) = 2.00 Total Depth (ft) = 0.47 Invert Elev (ft) = 100.00 Slope (%) = 2.00 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 5.95 Elev (ft) Section Highlighted Depth (ft) Q (cis) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Tuesday, Nov 28 2017 = 0.42 = 5.950 = 0.84 = 7.08 = 2.84 = 0.47 = 2.00 = 1.20 ' iu1.uu 100.75 100.50 ' 100.25 100.00 1 99.75 0 .5 1 1.5 2 2.5 3 ' Reach (ft) Depth (ft) 1.00 0.75 0.50 0.25 ,,. -0.25 'WEST ALLEY SWALE/ALLEY CONVEYANCE SECTION Channel Report - OFFSITE + ONSITE 100-YR FLOW=27.00 CFS Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, Dec 28 2017 <Name> User -defined Highlighted Invert Elev (ft) = 28.90 Depth (ft) = 0.62 (%) = 0.50 Q (cfs) = 27.00 'Slope N-Value = 0.018 Area (sqft) = 9.39 Velocity (ftls) = 2.88 Calculations Wetted Perim (ft) = 26.18 Compute by: Known Q Crit Depth, Yc (ft) = 0.58 Known Q (cfs) = 27.00 Top Width (ft) = 26.01 EGL (ft) = 0.75 (Sta, El, n)-(Sta, El, n)... (0.00, 29.75)-(6.00, 29.20, 0.016}(24.50, 29.00, 0.016}(25.50, 28.90, 0.016}(26.00, 29.30, 0.016)-(34.00, 30.00, 0.035) ' Elev (ft) Section ' 31.00 ' 30.50 1 -5 0 5 10 15 20 25 30 35 40 Sta (ft) Depth (ft; 2.10 1.60 1.10 0.60 0.10 -0.40 -0.90 Channel Report CURB CUT CAPACITY CALCULATIONS BASIN 4 p (PORTION; 0.18 ACRE) 100-YR FLOW=1.10 CFS 1 Hydraflow Express Extension for Autodesk® Auto CAD® Civil 3D® by Autodesk, Inc. Curb Cut - Basin 4 Rectangular Bottom Width (ft) = 2.00 1 Total Depth (ft) = 0.47 Invert Elev (ft) = 100.00 Slope (%) = 2.00 N-Value = 0.013 Calculations Compute by: Known Q Known Q (cfs) = 1.10 Elev (ft) Section Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Thursday, Dec 28 2017 = 0.14 = 1.100 = 0.28 = 3.93 = 2.28 = 0.22 = 2.00 = 0.38 iui.uu 1 100.75 1 ' 100.50 1 1 100,25 ' 100.00 99.7s 0 .5 1 1.5 2 2.5 3 Reach (ft) Depth (ft) I .00 0.75 0.50 0.25 M -0.25 I I I I M 11 [1 1 N N O G @ � q / I I] @ I � e 0 low � E 0 @ E @ re L2 � � � � 2� £ 4% E q § c aLu -- o k J&F i 7 w § k ■ 2 k ■2E � � B to § § § § § § ■ IA >CD m — _ 2 0 z � E (92£ C) CD 1 § k Ln B . co r- 2co a£co k k k I- § E R § 2 V § § k k IRt �� \ / . a=« Go § § § § k § § § § & icn E — A 02E k B Ln § `■— E ■_. 9 _ 2 ° € r- r- w w 2 a _ ' ( . ƒ � V) V N I m O ch L. CD �co E L 'O co I 0 0 0 0 CD 0 O N N cli 01Cl) f0 LO N 1� LO Ln O O W O O O n 0 m O U f0 N Q' 1n0 9L'6ZO9 '13 AUI 9Z'L£OS'13 TWO L :u-I - 60ti'OV+p e1Scn 0 < O Cl Cl O J N W i O J c� x uI £9'8ZOS '13 '^UI £Z'LE09'13 TWO IIeRnO - 00 00+0 e1S 0 o 0 0 0 0 0 _ 0 0 0 L W 11 I u u 1 1 N O 1 E . �S 0 MO r�n V to 75 L` 1 O M yNy O f O � o co LD W Ox O C N Y N O N L U > . O o N o � w o J > (U CI �^. � W 0.r N /0 t M O > y R u C 7 O. 10 o O E a w L : 0 z n �coo p x o J > Obi = m to fD O1 c a O O o O O O J > N (7 m ^ m CD to W M > L x O a^ay N WO m C Od fO O Q N O O L Y Go X OQ II a i7 G J > O) N N II S m N N E IU Q m 01 F Q L d tly F N L D v N 0 O g Z .0 V N Ui N C_ LL y b W 0 c O N z J a` l' APPENDIX E ' Detention Calculations 1 I I I I I I I I 1 I I I I 1 I I I 1 1 1 i 1 I DETENTION POND CALCULATION; FAA METHOD Project Number : 1252-005 Date : 2/18/18 Project Location : Fort Collins Calculations By: ATC Pond No : Concrete Vault Input Variables 7 Results Design Point 3 Design Storm 100-yr Developed "C" = 1.00 Area (A)= 1.04 acres Max Release Rate = 5.20 cfs Required Detention Volume 1677 ft3 0.038 ac-ft Time Time 100-yr Intensity Q100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume mins secs in/hr cfs (ft) (ft) (ft) 5 300 9.950 10.30 3091 1560.0 1531.4 10 600 7.720 8.00 4797 3120.0 1677.0 15 900 6.520 6.75 6077 4680.0 1397.1 20 1200 5.600 5.80 6959 6240.0 719.4 25 1500 4.980 5.16 7736 7800.0 -63.9 30 1800 4.520 4.68 8426 9360.0 -934.1 35 2100 4.080 4.23 8873 10920.0 -2046.7 40 2400 3.740 3.87 9296 12480.0 -3184.2 45 2700 3.460 3.58 9675 14040.0 -4365.2 50 3000 3.230 3.35 10035 15600.0 -5564.8 55 3300 3.030 3.14 10355 17160.0 -6804.7 60 3600 2.860 2.96 10663 18720.0 -8057.2 65 3900 2.720 2.82 10986 20280.0 -9294.0 70 4200 2.590 2.68 11266 21840.0 -10574.4 75 4500 2.480 2.57 11558 23400.0 -11842.4 80 4800 2.380 2.46 11831 24960.0 -13129.0 85 5100 2.290 2.37 12095 26520.0 -14424.9 90 5400 2.210 2.29 12359 28080.0 -15720.8 95 5700 2.130 2.21 12574 29640.0 -17066.4 100 6000 2.060 2.13 12800 31200.0 -18399.6 105 6300 2.000 2.07 13049 32760.0 -19711.1 110 6600 1.940 2.01 13260 34320.0 -21059.8 115 6900 1.890 1.96 13506 1 35880.0 -22374.4 120 7200 1.840 1.91 13720 1 37440.0 -23720.0 I 11 1 OUTLET RATING CURVE Concrete Vault Detention Orifice Project: 1252-005 Date: 10/15/2017 By: ATC 100-YR ORIFICE RATING Orifice Dia (in) 9.50 Orifice Area (sf) 0.4922 Orifice invert (ft) 0.00 Orifice Coefficient 0.65 Orifice Area (SF) Stage (FT) Outlet release (CFS) 0.4922 0.00 0.00 0.4922 0.25 1.28 0.4922 0.50 1.82 0.4922 0.75 2.22 0.4922 1.00 2.57 0.4922 1.25 2.87 0.4922 1.50 3.14 0.4922 1.75 3.40 0.4922 2.00 3.63 0.4922 2.2S 3.85 0.4922 2.50 4.06 0.4922 2.75 4.26 0.4922 3.00 4.45 0.4922 3.25 4.63 0.4922 3.50 4.80 0.4922 3.75 4.97 0.4922 4.00 5.14 I 1 11 1] I IJ DETENTION POND CALCULATION; FAA METHOD Project Number : 1252-005 Date : 2/16/18 Project Location : Fort Collins Calculations By: ATC Pond No : Paver Subgrade (Chamber System) Input Variables Results Design Point 2 Design Storrs 100-yr Developed "C" = 0.92 Area (A)= 0.58 acres Max Release Rate = 0.75 cfs i .ao Required Detention Volume 2997 ft' 0.069 ac-ft Time Time 100-yr Intensity Q100 Inflow (Runoff) Volume Outflow (Release) Volume Storage Detention Volume mins secs in/hr cfs (f1 (ft) (ft) 5 300 9.950 5.31 1593 225.0 1367.9 10 600 7.720 4.12 2472 450.0 2021.8 15 900 6.520 3.48 3131 675.0 2456.3 20 1200 5.600 2.99 3586 900.0 2686.0 25 1500 4.980 2.66 3986 1125.0 2861.2 30 1800 4.520 2.41 4342 1350.0 2991.6 35 2100 4.080 2.18 4572 1575.0 2997.1 40 2400 3.740 2.00 4790 1800.0 2989.8 45 2700 3.460 1.85 4985 2025.0 2960.1 50 3000 3.230 1.72 5171 2250.0 2920.8 55 3300 3.030 1.62 5336 2475.0 2860.7 60 3600 2.860 1.53 5494 2700.0 2794.2 65 3900 2.720 1.45 5661 2925.0 2735.7 70 4200 2.590 1.38 5805 3150.0 2654.8 75 4500 2.480 1.32 5955 3375.0 2580.3 80 4800 2.380 1.27 6096 3600.0 2496.1 85 5100 2.290 1.22 6232 3825.0 2407.2 90 5400 2.210 1.18 6368 4050.0 2318.3 95 5700 2.130 1.14 6479 4275.0 2203.7 100 6000 2.060 1.10 6596 4500.0 2095.6 105 6300 2.000 1.07 6724 4725.0 1998.7 110 6600 1.940 1.04 6833 4950.0 1882.5 115 1 6900 1.890 1.01 6959 5175.0 1784.0 120 1 7200 1.840 0.98 7069 5400.0 1669.5 1 i [1 I 1 I OUTLET RATING CURVE Pavers Subgrade Detention Orifice Project: 1252-005 Date: 10/15/2017 By: ATC 100-YR ORIFICE RATING Orifice Dia (in) 4.25 Orifice Area (sf) 0.0985 Orifice invert (ft) 0.00 Orifice Coefficient 0.65 Orifice Area (SF) Stage (FT) Outlet release (CFS) 0.0985 0.00 0.00 0.0985 0.25 0.26 0.0985 0.50 0.36 0.0985 0.75 0.45 0.0985 1.00 0.51 0.0985 1.25 0.57, 0.0985 1.50 0.63 0.0985 1.75 0.68 0.0985 2.00 0.73 EMERGENCY --- OVERFLOW FROM BASIN 2 (FULLY CLOGGED PAVER SCENARIO) SHEET _ FLOWS THROUGH DRIVE AISLE AND SOUTH TO \ W.ELIZABETH. EMERGENCY OVERFLOW SHEET FLOWS THROUGH DRIVE AISLE AND SOUTH TO W ELIZABETH ..mom.. EMERGENCY OVERFLOW WEIR DESIGNED FOR BASIN 3 Q700. SEE FOLLOWING CALCULATIONS - EMERGENCY OVERFLOW EXHIBIT (COMBINED BASINS 2 AND 3; PAVER SYSTEM AND CONCRETE North VAULT OVERFLOW) N T S EMERGENCY SPILL CALCULATIONS - CLOGGED PAVER Channel Report SCENARIO, 0100=BASIN 2 + BASIN 3 + BASIN OS2 = 17.04 CFS 1 Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. <Name> Rectangular Bottom Width (ft) = 30.70 ' Total Depth (ft) = 0.50 Invert Elev (ft) = 29.50 Slope (%) = 0.20 N-Value = 0.016 'Calculations Compute by: Known Q Known Q (cfs) = 17.04 1 ' Elev (ft) Section Highlighted Depth (ft) Q (cfs) Area(sgft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) Monday, Nov 27 2017 = 0.31 = 17.04 = 9.52 = 1.79 = 31.32 = 0.22 = 30.70 = 0.36 31.UU 30.50 30.00 29.50 1 29.00 0 5 10 15 20 25 Reach (ft) 30 35 40 45 Depth (ft, I 1.50 1.00 0.50 WE -0.50 L EMERGENCY SPILL CALCULATIONS - CONCRETE VAULT SPILLWAY Q100= BASIN 3 = 10.30 CFS I I I 1 1 I I i i 1 r t Sharp -Crested Weir: Project: 1252-005 By: ATC Date: 2/16/18 Governing Equations: This equation can be used to derive the stage -discharge relationship for a sharp crested weir where the depth of flow is small compared to the length of weir. Reference 1) Hydrologic Analysis and Design, Richard H McCuen, Prentice Hall, 1989. Pg.549. Q=3.3LH 1.5 ' where Q is flow rate in CFS ' where L is the crest length of the weir (F) ' where H is the height of flow over the crest (FT) L SHARP —CRESTED WEIR Input Parameters: Length (L)= 8.00 FT Crest Elevation = 0.00 IFT Depth vs. Flow: Depth Above Elevation Flow Crest (ft) (ft) cfs 0.00 0.00 0.00 0.15 0.15 1.53 0.30 0.30 4.34 0.45 0.45 7.97 0.54 0.54 10.33 .0— Q100 0.69 0.69 14.97 Q100 = 10.3 CFS (Max inflow from Basin 3) I Stormwater Detention and Infiltration Design Data Sheet Project #:MZ-WS Stormwater Facility Name: Concrete Vault Detention Facility Location & Jurisdiction: User (Input) Watershed Characteristics Watershed Slope = 0.015 ft/ft Watershed Length -to -Width Ratio = 1.10 L:W Watershed Area = 0.97 acres Watershed Imperviousness = 90.0% percent Percentage Hydrologic Soil Group A = percent Percentage Hydrologic Soil Group B = percent Percentage Hydrologic Soil Groups C/D =1 100.0% percent User Input: Detention Basin Characteristics WQCV Design Drain Time = 12.00 hours After completing and printing this worksheet to a pdf, go to: httos:llmaperture.diizitaidatasemices.com/evh/?viewer--cswdif create a new stormwater facility, and attach the pdf of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period = Two -Hour Rainfall Depth = Calculated Runoff Volume = OPTIONAL Override Runoff Volume = Inflow Hydrograph Volume = Time to Drain 97%of Inflow Volume = Time to Drain 99% of Inflow Volume = Maximum Ponding Depth = Maximum Ponded Area = ' Maximum Volume Stored = Stormwater Detention and Infiltration Design CRS Spdsht-ConcVault.xlsm, Design Data User Defined User Defined User Defined User Defined Stage [it] Area [ft-21 Stage Ift] Discharge [cfsl 0.00 0 0.00 0.00 2.00 1,205 2.00 3.60 3.00 1,206 3.00 4.50 4.00 1,207 4.00 5.20 WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 0.53 0.98 1.36 1.71 2.31 2.91 3.67 0.026 0.071 0.102 0.131 0.182 0.233 D.3DD 0.025 0.070 0.101 0.131 0.182 0.233 0.299 0 1 1 1 1 1 1 1 1 1 1 1 1 1 0.36 0.90 1.24 1.53 1.99 2.57 3.41 0.005 0.012 0.017 0,021 0.027 0.028 0.028 0.001 0.006 0.011 0.016 0.027 0.043 0.066 n acre-ft acre-ft cre-ft lours lours t acres cre-ft 12/29/2017, 12:47 PM I Stormwater Detention and Infiltration Design Data Sheet 1 TIME (hr] i i 100 1 10 DRAIN 7NdE Ihrl ■ Stormwater Detention and Infiltration Design CRS Spdsht-ConcVault.xlsm, Design Data 12/29/2017,12:47 PM I Stormwater Detention and Infiltration Design Data Sheet Project M:1252-WS Stormwater Facility Name: Paver Detention (Chamber System) Facility Location & Jurisdiction: User (Input) Watershed Watershed Slope Watershed Length -to -Width Ratio Watershed Area Watershed Imperviousness Percentage Hydrologic Soil Group A Percentage Hydrologic Soil Group 8 Percentage Hydrologic Soil Groups C/D 0.008 ft/ft 2.80 L: W 0.61 acres 64.9% percent 0.0% percent 0.0% percent 100.0% percent User Input: Detention Basin Characteristics WQCV Design Drain Time = 12.00 hours After completing and printing this worksheet to a pdf, go to: https://maperture.digitaidataservices.com/gvh/?viewer--uwdif. create a new stormwater facility, and attach the pdf of this worksheet to that record. Routed Hydrograph Results Design Storm Return Period = Two -Hour Rainfall Depth = Calculated Runoff Volume = OPTIONAL Override Runoff Volume = Inflow Hydrograph Volume = Time to Drain 97%of Inflow Volume = Time to Drain 99% of Inflow Volume = Maximum Fondling Depth = Maximum Forded Area = Maximum Volume Stored = Stormwater Detention and Infiltration Design CRS Spdsht-Pavers.xlsm, Design Data User Defined User Defined User Defined User Defined Stage [ft] Area Ift-2) Stage [it] I Discharge (cfs) 0.00 0 0.00 0.00 0.75 5,136 0.75 0.45 1.50 5,137 1.50 0.63 2.00 5,138 2.00 0.73 WQCV 2 Year 5 Year 10 Year 25 Year 50 Year 100 Year 0.53 0.98 1.36 1.71 2.31 2.91 3.67 0.010 0.031 0.049 0.066 0.097 0.127 0.167 0.010 0.031 0.049 0.066 0.097 0.127 0.167 2 2 3 3 4 4 5 2 3 3 3 4 S 5 0.18 0.40 0.53 0.65 0.83 1.01 1.28 0.028 0.062 0.083 0.102 0.118 0.118 0.118 O.IX12 0.012 0.022 0.033 0.053 0.075 0.10E n acre-ft icre-ft acre-ft lours lours t cres cre-ft 11/28/2017, 1:30 PM 1 Stormwater Detention and Infiltration Design Data Sheet DRAIN TIME ]hr] 10 100 Stormwater Detention and Infiltration Design CRS Spdsht-Pavers.,dsn, Design Data 11/28nO17, 1:30 PM I APPENDIX F ' Erosion Control Report I I I I 1 I I k I I I 1 I ■� NORTHERN NORT ENGINEERING Union on Elizabeth ' EROSION CONTROL REPORT A comprehensive Erosion and Sediment Control Plan (along with associated details) has been 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. 1 Grading and Erosion Control Notes can be found on the Utility Plans. The Final Plan set contains 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. Final Erosion Control Repot APPENDIX G ' Current Effective FIRM Panel I I I I I I 1 1 I I I I I 1 Ci I i 1 1 1 I 1 1 i IUI 1 n l( li 1 1 �I ICI Pdl1 Nu 1, Il Id i N'ql h t. 1 1111 I•,. jil,�; I !' l i 1' i E t 1 t t 1 :E ` I " 3 L. II E 1 3 E 4. I �� :i @ i 1It i 19 it 4 1 l e ` '. i �1;r E:'El:•�i`i !',lrl I jstl E' I`'E!•' I `11� i,i��i I !, , , 1 ,, ! ! tt !di l I I' �1 j' 1 E,,IY, � ,lay 1t11111!'1iEIIil1,1' E�. t;�t 1 r f � r/yei E ��� 6 lll��l� 111, 1 114+.i;ij/�1i11 1 ►,:t1tr. ,�1� 11 ginl 1 1 it Ithi Oiilall U w �w lift' 1 i � ! 1 c 4 , 1 + 1 ! 5 lei t � ! 1 � BI � is s � f CT &O 1 i � I ► ` e Plju•' ( vaP1 �jil ','i '!li ►`1'.Ei f t I . �, I EI 1',� rl�; itj .,r �" I ':Ei 11! :�!' .I `i ,i,� I' li 1 '�E,�` !I 1 !:' ''111` :`l,l� lFr ,1$1,1 ,i=1:. 11 • Ei,l,�(�tM 1� `'1 !,tl11; ,i •`�' 1,, ! 1,,l E� Id, �trl if�hEE�i+ i11ll!,�E�E�j rii lit :�ljj; l;I{l� i j fli �E, 1�E'�t+ all Ei i 't tr {,111,11`{1jE 1�,1 •��1� E!}E�il iii l iEl lid I'�l;ii l�iif 1Lt iE,ii iilE� i idlit, !il f11 1,;fii,l i°►1 APPENDIX H Approved Stormwater Variance Application I I I I I I I I I I I I I I I I Stormwater Alternative Complianceffiriance Application City of Fort Collins Water Utilities Engineering Engineer Name Aaron Cvar Phone 970-221-4158 Street Address 301 N. Howes, Suite 100 City Fort Collins State CO Zip 80521 Owner Name Plum Owner Ft Collins CO LLC Phone Street Address 999 South Shady Grove Road, Suite 600 City Memphis She TN Zip 38120 'Section 8: ProposedProject Project Name Union on Elizabeth � Project/Appl!cation Number from Development Review (i.e. FDP123456) ' Legal description and/or address of property Replat of Portions of Lots 3 and 4, Campus West Shopping Center Description of Project Mixed -Use building development ' Existing Use (check one): r: residential C:; non-residential r., mixed -use r vacant ground Proposed Use (check one): r. residential r, non-residential G: mixed -use C, other If non-residential or mixed use, describe in detail Development of a mixed -use building a associated utility work, adjacent sidewalk and Stormwater improvements 'Section C: Alternative ComplianceNarianceInformation State the requirement from which alternative compliance/variance is sought. (Please include ' applicable Drainage Criteria Manual volume, chapter and section.) Variance from providing water quality treatment for 1001yo of the site. What hardship prevents this site from meeting the requirement? The proposed site is constrained by a lack of a below -grade outfall, floodplain elevation requirements along Elizabeth and grading tie -In constraints with the adjacent property to the east of the site. ' Additionally, there is a significant offsfte flow (25.3 CFS) that passes through the west side of the site that precludes treatment facilities along that flowpath through the project. What alternative is proposed for the site? Attach sepw►ate sheet N necarary Water quality treatment is being provided for the majority of the site (82.6%). Drainage along the east will be captured and routed through landscape beds prior to leaving the site, providing some treatment. Pavements along the south are non -vehicular, with minimal pollutants expected in stormwater runoff from those areas. Attach separate sheet N necassW pop 2 I 1 The owner agrees to comply with the provisions of the zoning ordinance, building code and all other applicable sections of the City Code, Land Use Code, City Plan and all other laws and ordinances affecting the construction and occupancy of the proposed building that are not directly approved by this variance. The owner understands that if this variance is approved, the structure and its occupants may be more susceptible to flood or runoff damage as well as other adverse drainage issues. Signature of owner:, The engeler"'1Ser"eby ci descriptions is correct. ' Signature of 1 LCC s, to c information, along with the reference plans and project We complete application submitted: 3 the t% We of approval/denial: J4 / -ZO 4 Variance: t �.t a sunal !v ' Approved by ' Entered In UtilityFile ❑ no approved ❑ denied 3/zI1 B PE STAMP I MAP POCKET I I I �I I I I I I I I I I I I OSz I m Dr mwawr rlea LNG rE reoa I eHHDAWDaP•TewLmxunOx RUMORED? / \ — 11.a �Er _ -- Ost COMAEIE.NI ' / / IF THEEKSH GREEN SUISSE FEE NO 0 If I PRERECORD \ I cGxciTERAN \ D I FRDro® IA I l \ If IWEEI OIL-- _ I I PBUrosEDz if \7 81 1 .. 1 1 II -- « 1 — \i; ou: ■ 411 ..� __ ■ - I I 1 1 EDT toXam AaI I \ I msSXELDa LLC — \ � ■ p ___ ___ �_ I I me9HIBm Br \-- N. 1 \ I I I /� I ■ l \ \ I I 11 I / ■ I I /'LL � I -qt -- I i l i � �� Ic % I n� I. - �/ r` i � / I 11 1 / �,I 1 3 A If IF I V-e y�. \ / t«. � eIDEWWXovgx '�' ' / \ \mil if If I i II It I 7 IF \V Lm t.GM.weWxdr i E7 LTV ; 1 2b I I_ QClUC DIN waxtrn I 1 1 I 01;; n I� .—� -1 I /mar DRrxa HBuWpi I I 1 I I _ .1 -..- I-- CONCRETE r IS DETENTION VAULT — /I F �♦ wTEcusCanER ` — eHwivwD CENTER =A �- I 3 II tmmxas:0=7 _ / �H i mawaox I I umwiuiuimar I BXxB'.RDEG9R+E j I I PAVE RICHAMSERYRH i I I r / 1 1 DETENTION AREA % tmRIFE. I \ULU FEEIRFACNl0.CNRI/ # s u a ; I: I� -- ----- — / II I FEE waaleni ■ U)//I ® ■ / FNDIrosEn XmRUsm II • \ `� awwr IF DHR1ET 81MICNIE / —`\`H I mEi OPODaw / I i HE 1 ■ - - _ .��I 1 / jay — / ® \ % ______ a.■■.■i■■i IN iii a■i ■.i■ ® I \ / / / ,lr{, r ♦ I / I tmm naaDPLm \ ____ PTLORmmz 11 ■ � 1 --t— — _ ___ _ B _ __m / IH.HCIV0.PN _—_ aHawr III FICHE' eII9161 WE waEDED --- FwvxEoz 11 PRo --� LwFnr --_ SXIEWXKpILWAI `` \ EmII WEST ELIZABETH STREET _ (ea ROW) WERE HmmFLwDPINN RARE____—_` aMHm DHI.HBI I � I \\ ELSTIN6N•RCPSIV1YpUIN \� \) I MUNAGE SUMMHUIy TABLE DEAIXI ID TOFK AREA ITW CIDD 2-. BE I84 D IN: h 1111ie (b) IN IS � d3 A A ObNO I 28 O.II ON PW 71 SIT 3[ E[ SEA? SURE03) SO SA 33 1 135 1 aN I I SO DI 8.9 SIDEJ ® NORTH • DNA 'MAST. , LEGEND: UUMOSED sraa swBl — FERNISTINGOONTOUR WRITE — PROPERTY BOUNDARY R WE .�FEREEREEI DESreH NIGHT Q GENERATE BASIN InDFE- aao« xBE) MIGA DRAMAAHE BASIN BOUNDARY ■ ■ I.RGGFDEEDBwALEEEGTDTa u NOTES: 1. GWWAEI TFOHUHICHMReIIETHWTEDM H9,Af8FR ,H�`DDITIlaui miowuTw, BENCHMARK ATT� SOUTIM£9T CORNER OF WEST EULBETIND CpIBrIr1111CN AWL ON AGGRESSOR TRAFFICusE. ELUIRSONGIS CITY OF FORT COLLINS BENCHMARK 19,97 AT NEBWMEAS CMHEROF WEST INIZARTH.W OHIELOa SIT CNACONCRETETRAFFICafNN BASE ELEVRE DATUM. SURROUNDING DEVELOPMENTS PAYE ONO NGwR UNADJUSTED lEW THE RISFFOR IC4 WTMa. IF INTRICKII UWLIUBTED¢ATUM IS REQUIRED F WR ANY NPAOSE THE FOLLOW NO SCRATCH 9HODEBE USED NOROZ INADNETED•HAUX S1S DOES BE MEANINGS THE BASIS OF BE ER HGS HE THE SOUTH LINE OF LOT S US[SWUNG NORTH a9'0i']9' WEST. NNNNNNNNN FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION f,N1 UNKLA I ' NOTIHaTICN CENM BE C LORADD KnmwRWsbe1M Cw OWN EINxER REN EDINAMEOUNG FOR RME MI WA City of Fort Collins, Colorado UTILITY PLAN APPROVAL APPROVED: CItY ENEbw AY CHECKED EYE xebr a Fulmebr Uumi, DF4 CHI BY: a�emwebe WILD DE4 CHECKED BY: —Te.TF�f� py WEpXD BY DeY CHECKED BT. �i Yeem°^ en o� Deb LAN LL- `. ,OP,R.DIMRE ® IN Br w \ 3 ! a — — — — — — — — — IN _.. . _____ __ ______.. _...—_. _...—..._ 1 n FFE 3290 r -- i` \\ I ------------- =m - - —WEST ELIZASETH STREET MIXED -USE BUILDING SUMMARY ELEY.0 4MMVp1N MAECrEPEV. INAY➢YI A YRYR B Nuclei C PEwwTary Roc° EIEVAIRM �.Y IT \ I I I / ® NORTH m Y I.IIN FEET) LEGEND: PROMISED ST�� x WHARDEORM INLET NOTTINGCMIOVR _pq} FN>, E°PRANDOLOCONTIOUR ... { O %OPOSEDBW CURE&CUTTER WO \ RVV➢9 \ ROESiPVNnCCE99 T— sW wcTEm __�__ C�RWPOPANITW l �� / tlER8H = c ELEvailax wwr 5p00 O�cy�Iil`/CFH (� — BAY PLDODELEVArNIXIG}IGLOIq M/WW\^ �2 O �FV VYYaalll\\\ <' IWYW GGPUY ...... ... •: uaDMRI NMtCSU ,WNORW°W) •�._. . .__ VX-YN / ,�\ IPEN WRI — i \\ FIELD SURVEY BY: r \ - - — �'- NOR RING — PROM aB METE MUTSU W17 LLJ fY HOME, W _ IFI. (OWNER POECITIDle mDATE `= Wki rz / ; `\ BENCHMARKS: cv \ Z \ FBI WNM'. REVIEWS Q ZW , / EV�HC9C�BCIGCRALBUfE�Mm"`M1F�ELVLeEm PM CM9111VFCN avE.(wa Y ONCRE CONCRETE j OF WEBi ELQ.RYTHNMCMQD9ST., ONACCHCARE ( TRAFRCWSIGTPWDSfl09COPxEP Lar>CPMN9ME8f ELE. ESC YCKMTLIMS R °DLviYr�sw 0 SET Ixc XA LonTNA axc B -- FEgiaR THOR CATUM of s AVE ueED GwzBDUPausreDFoamE RVERTIrx oamMs. HAVE 111° EIPMFIXY WIII VNODlV9R➢ CWTUM IB REQUIRED FOR MY PURPOSE, THE FOLLOMNO DOMINION SHO.Rn ME DIED NI USUAUSTED• ruVIAST$ NF \ —EaDFY RwQ YssoFBEAwucB isnE Bwnxwar DIP LOT sIY SEAMING rvaxmero°x WEm. t NOTES: mriv ky IF 1 gEFERiOTEMiFORLOi.VEA9,1MCi Sl E. MB, LOi°MEXBSWB,UMIIV CH I WNn OTHER OHEI MAHD 0,11EP SURVEY NrgYNTI N / • THIS PROTECT IS LOCATED WITHIN A CIn.REWurEO 1 WYFM 0.CCMYAY MO RUO FRNGE y — COMPLY MUST WTH CHARTER 10 OF n@GTV C°CE. I 3. ALL ELEVAVONS DIRECTED IN PLAN VIEW AND BEFCHMPTMB LILTED PERSON ARE FOR THE CRY OF WWWGW I FONT COLLINS VE RTICAL CONTROL EATON IWSE)VN �g xIt Ed iiii F�1 i ITEMS LOCATED IN THE FLWDWAY THAT CAN FLOAT IE.G., RCNIC tADES.BE¢'0.K.HS, ElC.1 VBi BE ANCHORED. M I_ '� PERMIT SHAL BE REQUIRED FOR EACH SIZE CONSTRUCTION ELEMENT W TIE I agR�HPLAINY xI INCLUDINGWILDING. HE FLOOCRAx USE RPWi FOR THE EASIER WILL SE IF ® RDED,T,NETMEDFWL°xGEYT PUnaN. / / S. AFCCOVILNx USE OWNER AND NO CONFETTICSFUNEU ED PRIOR To REPROCESSING MY CUM WORK WITH N THE FLODOWAY I- - REMOVN LAHOsf NGL \ ] WSTR PBENTSHILL BENLOWEDW THE ROJLL'IaY N1EIHFA TEMPO RYOPMATE E Nv (SUNK U ANEXi. SCAM1x65XN.LNWNEETLXE FOR0 THE WAY REFER 1IIr'I I) / REFER FOR VxWOX ELIYBETX, DATEDMWCH B, ENSIGN S TO THE U% A L _,T B A CONSTRUCTIONaSOWILLU NEv.T ox cERrFwEwnaEAL9xweDYFaREI.cFnnFIC/.TEa r r _ OCCVFNNCYw LLSE ISSA°. TDo 1 _ �� �� ° ALL 1NYAKM C EOLENLYIOYPLACED Ar°PPSOVETHE PEWUttTRYfLCW PROMOTION y _ EIEVALN.W. W 11, PpXIZIMRN CONTROL, CHIP OF FORT WWx s GROUND MASTER CCMRM. rVB Iy X is' — urN.e T FOR DRAINAGE REVIEW ONLY NOT FOR CONSTRUCTION City of Fort CoI Colorado UT1LMY PLAN APPROVAL APPROVED: OtB mOmFY D.M CHECKED ST. I.IFF k EU M.tlrt YtWtr DFte CHECKED Or TWn..4eY Om� ALF pIEG3D BY: D", CHECKED OF IF Engineer o.v CHECKED Or. �� Dsi. w z J d 0 0 O Sheet CODS 11 s of 20