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HomeMy WebLinkAbout1.37 EngDesign-SedimentControlr -r E COLORADO EROSION AND SEDIMENT CONTROL PLAN RIVER EDGE COLORADO GARFIELD COUNTY, COLORADO OWNER/APPLICANT: CARBONDALE INVESTMENTS, LLC 7999 HWY 82 CARBONDALE CO 8 1 6 2 3 970-456-5325 CONSULTANT: 8140 PARTNERS, LLC PO BOX 0426 EAGLE, CO 81631 JANUARY 14, 2011 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado EROSION AND SEDIMENT CONTROL PLAN RIVER EDGE COLORADO GARFIELD COUNTY, COLORADO TABLE OF CONTENTS INTRODUCTION 4 A. BASIS 4 B. PURPOSE AND SCOPE OF REPORT 4 C. DESIGN STANDARDS 6 D. FINDINGS 7 II. PROJECT LOCATION AND DESCRIPTION 8 A. PROJECT LOCATION 8 B. PROJECT DESCRIPTION 8 III. PLAN BASIS 9 A. EXISTING SITE CONDITIONS 9 1. RIVERS, CREEKS AND FLOODING 10 2. WETLANDS 10 3. GROUNDWATER 11 4. TOPOGRAPHY 11 B. SPECIAL PLAN CONSIDERATIONS 11 1. SOILS 12 2. GEOTECHNICAL CONDITIONS 13 C. HYDROLOGIC AND HYDRAULIC CRITERIA 14 1. RAINFALL SOURCE 14 D. HYDRAULIC CRITERIA 16 1. CONVEYANCE CHANNELS 16 2. STORM SEWERS 16 3. ROAD FLOWS 16 4. EMERGENCY RUNOFF CONVEYANCE 16 IV. GRADING AND DRAINAGE PLAN 17 2 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado A. OVERALL CONCEPT 17 1. GRADING AND DRAINAGE 17 2. OFF-SITE BASINS 18 3. SURROUNDING LAND USES 18 4. WATER QUANTITY AND QUALITY STORAGE 18 B. SPECIFIC DETAILS 19 1. ONSITE BASINS 19 2. MAJOR DRAINAGEWAYS 20 3. WATER QUANTITY AND QUALITY STORAGE FACILITIES 21 V. EROSION AND SEDIMENT CONTROL 22 A. OVERALL CONCEPT 22 B. RECLAIMED CONDITIONS 23 C. PHASED CONDITIONS 24 D. FINAL CONDITIONS 25 VI. COST ESTIMATE AND METHOD OF FINANCING 26 VII. LIST OF REFERENCES 26 APPENDICES APPENDIX A: VICINITY MAP AND PROJECT SITE DRAWINGS APPENDIX B: RAINFALL INPUT APPENDIX C: IDF CURVE DATA APPENDIX D: BASIN DELINEATION MAP APPENDIX E: PRE- AND POST -DEVELOPMENT WATER STORAGE AND QUALITY DATA APPENDIX F: CDPHE STORMWATER MANAGEMENT PLAN APPLICATION APPENDIX G: WETLANDS DELINEATION REPORT 3 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado I. INTRODUCTION A. BASIS This Erosion and Sediment Control Plan ("Plan") has been prepared in support of an application for PUD Plan Review ("Rezoning") and Subdivision Review ("Preliminary Plan") for the proposed River Edge Colorado ("Project", "REC", or "REC PUD") in accordance with the requirements of the Garfield County Unified Land Use Resolution of 2008 ("ULUR"), as amended. This Plan specifically addresses the requirements of Section 4-502.C.4 of the ULUR as required under Section 5-501.G.11.e and Sections 6-301.B.5.e and 301.C.8.r(5), meeting the criteria of Sections 7-203, 7-204, 7-205,7-206, 7-207, 7- 303, 7-212.B and 7-701 of the ULUR. This Report is supported by other referenced documents submitted as part of the REC rezoning and preliminary plan applications including the River Edge Colorado PUD (Rezoning) and Subdivision (Preliminary Plan) Drawing Package ("Drawing Package"). B. PURPOSE AND SCOPE OF REPORT The primary purpose of this Plan is to provide preliminary planning and design information for erosion and sediment control efforts depicted on the engineering plans (See Erosion and Sediment Control Plan, ES01-04 Series in the Drawing Package). This Plan (in combination with the Erosion and Sediment Control Plan, ES01-04 Series in the Drawing Package) documents that the Project meets the requirements of the ULUR in all respects, except as otherwise provided herein. The Plan further serves as the design framework for final design efforts to be completed in association with each Final Plat. For clarity purposes, the following lists the submittal requirements under Section 4- 502.C.4 of the ULUR and the location of the required information within this Plan or the drawings in the Drawing Package: • Site Map: Showing locations of any existing structures, waterbodies, or hydrologic features on the Project Site. (Series ES01, Drawing Package) • Drainage Structures: Showing locations of existing and proposed drainage structures or natural drainage features affecting site drainage on the Project Site and within 100 feet adjacent to the Project Site boundary. (Series ES01 and ES03, Drawing Package) • Drainage Structures: Preliminary engineering design and construction features for drainage structures to be constructed. (Series DR01 and ESO4, Drawing Package) • Topography: Existing topography with necessary detail of the Project Site and within 100 feet of the Project Site boundary. (Series ES01, Drawing Package) • Grading Plan: Grading plan showing the proposed topography including elevations, dimensions, location, extent and slope of all proposed 4 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado clearing and grading including building site and driveway grades. (Series ES03 and ESO4, Drawing Package) • Soil Stockpile and Snow Storage Areas: Probable locations of soil stockpiles and snow storage areas. (Series ES03, Drawing Package) • Drainage Plan: Proposed drainage plan. (Section IV of this Plan and ES03, Drawing Package) • Equipment Storage Areas: Location of storage areas designated for equipment, fuel, lubricants, chemical and waste storage with an explanation of spill containment structures. (Series ES03, Drawing Package) • Temporary Roads: Location of temporary roads designed for use during the construction period. (Series ES03, Drawing Package) • Areas of Steep Slope: Areas with slope of twenty (20) percent or greater by location and percentage of slope, both for the existing site conditions and within the developed area. (Series ES01 and ES03, Drawing Package) • Construction Schedule: Construction schedule indicating the anticipated starting and completion time periods of the Project Site grading and/or construction sequence including the installation and removal of erosion and sediment control measures, and the estimated duration of exposure of each area prior to the completion of temporary erosion and sediment control measures. (Section V.0 of this Plan and Series ES03-04, Drawing Package) • Permanent Stabilization: A brief description of how the Project Site will be stabilized after construction is completed. (Section V.D of this Plan) • Erosion Control Measures: Plan view drawings of all erosion and sediment control measures showing approximate locations and site drainage patterns for construction phases and final design elements. (Section V of Plan and Series ES02-04, Drawing Package) • Estimated Cost: Estimated total cost (installation and maintenance) of the required temporary soil erosion and sediment control measures. (Section VI of this Plan) • Calculations: Calculations made for determining rainfall, runoff, sizing any sediment basins, diversions, conveyance or detention/retention facilities. (Section III.0 and IV.B of this Plan) • Adjacent Land Uses: A description of neighboring areas with regard to land use and existing pertinent features such as lakes, streams, 5 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado structures, roads, etc. (Section IV.A of this Plan and Series ES01, Drawing Package) • Stormwater Planning Concept: Description of the stormwater management planning concept for the Project Site, including both structural and non-structural Best Management Practices (BMPs). (Sections IV and V of this Plan) • Hydrology and Hydraulics: Hydrologic, hydraulic and all other calculations used to size and design drainage facilities and/or structural BMPs. (Sections IV.B of this Plan) • Maintenance: Requirements for all proposed BMPs discussed including access, schedules, costs, and designation of a responsible party. (Section V of this Plan). • SWMP: Copy of the Stormwater Management Plan application to CDPHE with date of submittal. (Appendix F of this Plan) • Signature Blocks: Signature block for owner or legal agent acknowledging the review and acceptance of responsibility, and a signature and stamped statement by the qualified individual acknowledging responsibility for the preparation of the Erosion and Sediment Control Plan. (Not included, required only as part of Final Plan or when construction is authorized) C. DESIGN STANDARDS The following standards and criteria were used in preparing the drawings, plans and reports: • ULUR; • 2009 International Building Code (as amended by Garfield County); • Urban Storm Drainage Criteria Manual ("USDCM") dated June 2001, Urban Drainage and Flood Control District ("UDFCD"), Denver, Colorado; and • Colorado Floodplain and Stormwater Criteria Manual, dated 2006, Colorado Water Conservation Board; In addition, where certain necessary standards and criteria were not included as part of the local standards or where standards were not applicable due to site conditions or the proposed development program, state and federal codes and statewide or nationwide standards were utilized as an alternative. Where such state and federal standards and criteria specifically conflict with an applicable ULUR standard or criteria, modifications have been requested as part of the REC rezoning and preliminary plan application and are included as a part of the Rezoning and Subdivision Justification Report. 6 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado D. FINDINGS Based on the preliminary information provided with and in support of this Plan, William S. Otero P.E. (Colorado Registration #32163) has determined through his direct involvement in the preparation of the document and the associated plans that the Project has been designed, and may be designed and constructed at the time of Final Plat, in a manner that meets or exceeds the general requirements presented in Sections 7-203, 7-204, 7-205,7-206, 7-207, 7-212.B, 7-303, and 7-701 of the ULUR. The design, as presented, includes two regulatory modifications with respect to storm drainage where in the opinion of the William S. Otero, Project Engineer site conditions and the Project benefit from an alternative standard being applied. The first modification is a request to use the USDCM, as amended, as the criteria for analysis and design of channels and hydraulic structures and primary guidance document for the selection and design of stormwater quality BMPs. This modification is being requested in an effort to clarify standards and specification that will be applied to the Project since the ULUR does not provide detailed criteria for "suburban" or "urban" forms of development and the USDCM is recognized as being one of the most comprehensive drainage criteria manuals available in the State of Colorado and has been used as the basis for the development of local drainage criteria manuals and in drainage design and review process by a wide variety of municipalities in the State from Grand Junction to Denver to Fort Collins. Without these criteria, the ULUR fails to provide adequate guidance and a design basis to address the types of development, conditions and infrastructure proposed. The USDCM is approved and accepted by the Colorado Department of Health Water Quality Control Division (CDPHE-WQCD) as a reasonable basis for design. The second modification is a request that only the Water Quality Capture Volume (WQCV), and not the total stormwater volume (i.e., quantity storage) required by the ULUR, be detained prior to discharge off the Project Site to either Cattle Creek or the Roaring Fork River. The primary reason for this request is that the Project Site is located at the confluences of the two major perennial waterways and detention of surface runoff at historic rates provides little value or could even be detrimental to these waterways since it delays the releases from the Project Site in a manner that could coincide with the peaks flows from larger contributing basins up stream (i.e., adding to the magnitude of the peak flow). If these larger stormwater volumes are not detained, the peak flows generated from the Project Site will be released prior to these other peaks entering the areas. Furthermore, stormwater runoff from the Project Site does not discharge to or impact adjacent properties or downstream drainage structures. Should the County believe that quantity storage in addition to quality storage is required, the storage volumes for both quantity and quality are provided herein and the area necessary to store this increased volume is available within the locations identified on the engineering plans to accommodate the volumes without any impact to lots within the Project. It is the opinion of William S. Otero, Project Engineer that detaining excess quantity volume is unproductive at best and potentially damaging to downstream areas at worst. 7 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado II. PROJECT LOCATION AND DESCRIPTION A. PROJECT LOCATION The Project is located along State Highway 82 ("SH 82") between the City of Glenwood Springs and Town of Carbondale near the junction of County Road 110/113 ("CR 113") and SH 82. The property is located almost entirely west of the Roaring Fork Transit Authority ("RFTA") right-of-way and east of the Roaring Fork River and the Roaring Fork Conservancy ("RFC") Conservation Easement (i.e., Grant of Conservation Easement dated February 3, 2000, recorded at Reception Number 559036 and survey map, recorded December 24th, 2008, recorded at Reception Number 760571 in the real property records of Garfield County, Colorado). The Project straddles Cattle Creek which is also located within the RFC Conservation Easement. A vicinity map is provided as Exhibit 1 in Appendix A. The Project covers approximately 160 acres ("Project Site") as shown and described on the Project Site drawing [Exhibit 2(a -d), Appendix A]. The Project is proposed by Carbondale Investments, LLC ("CI"). B. PROJECT DESCRIPTION The Project is a proposal to create a walkable clustered -form of residential development with neighborhood amenities including naturalized open space and enhanced wildlife habitat, community recreation, parks, and neighborhood agriculture that is designed to serve the residents and preserve and provide reference to the rural character and agricultural roots of the Roaring Fork Valley. The Project aims to have a strong historic identity back to the days of 'old Colorado' when compact neighborhoods formed with a strong sense of community based on the land and surrounding landscape. The REC landscape aesthetic will be simple, informal, and place emphasis in the use of plant and landscape materials local, adaptable and appropriate to the climate and environment of the area. The Project will include approximately 366 residential units of various sizes and types including 55 affordable homes and one exclusive executive lot for a custom home. Housing types will range from attached homes to small single family attached and detached garden homes, village homes, and larger estate homes. Smaller garden homes are anticipated to be designed for younger residents that are looking for their first home in the County, while village homes and estate homes will provide move up opportunities for growing families. Densities in the Project are proposed at less than 21/2 units per acre. Lot sizes will vary from over 1 acre to approximately 5,000 square feet for single family homes, and 1,700-5000 square feet of lot area for each garden home. Most of the units back to either proposed active parks or reclaimed open space to help enhance the connection to the land. The REC layout and design is depicted in the PUD Plan, PUD01-03 Series and the Preliminary Plan PRPN01-03 Series of the Drawing Package. The architectural theme will be complementary to the traditional architecture of the valley. Generally, exterior materials will include wood, stone, brick, stucco and cement board siding. Varied roof heights and articulation of the front elevations will be used to break up the massing and provide street -level appeal. Front porches and covered stoops are included on homes to emphasize the entry and connection to the sidewalk and street. Roofing will include dimensional shingles, metal, or other materials appropriate to the building style and that roofs will generally be pitched. Gables, wall plane and 8 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado roofline articulation, bays, balconies, porches, canopies and arcades will be used in the design of various buildings. The selection of materials will minimize the exterior maintenance of the homes to help maintain a quality appearance for the long term. The street pattern and pedestrian network are designed to facilitate community interaction. Streets have detached sidewalks with designated cross walks at major intersections and landscaped areas that create a comfortable environment for walking. On -street parking in most areas will further buffer vehicular and pedestrian uses. Internal circulation is maximized and dead-end streets are limited. Alleys are used where appropriate to enhance the streetscape and achieve a mix of housing styles. A soft trail system is used to connect open spaces and other common elements with the sidewalk network. The homes are placed close to the streets to help define the streetscape space and provide visual interest to pedestrians. Street trees and plantings are proposed to enhance the aesthetics of the street. The community is served with a variety of recreational facilities and a neighborhood center that could include meeting room(s), fitness room, offices, kitchen, restrooms, recreational facilities, and limited community service use such as a day care facility, deli/coffee shop, or health club. Parks will provide informal recreational opportunities within the community and will likely include tot lots, playfields, and trail system. The west portion of the property is generally set aside as the naturalized area that buffers the RFC Conservation Easement along the Roaring Fork River. The soft trails around the property allow residents to enjoy the river and wetland areas without disrupting the environment in conformance with the terms of the RFC Conservation Easement. More than the minimum open space requirements will be met by the project. Nearly 50% of the Project Site is in some form of open space, common area or park. Finally, opportunities for productive and edible landscapes, including community gardens and neighborhood orchards are integrated and dispersed in between the residential land uses as gathering and focal places for residents connecting REC to its agricultural heritage. The combination of trails, recreation areas, and open space system with the ability to engage in 'interactive community agriculture' on a small scale will make REC a very desirable place to live, filling a unique niche not yet met in Garfield County. This unique combination will help establish a sense of place, foster community, and engage residents with their immediate environment. It is intended this overall outdoor focus will set the tone and become a major driver of the identity of REC. III. PLAN BASIS A. EXISTING SITE CONDITIONS The existing Project Site features/conditions and features/conditions immediately adjacent to the Project Site are shown on the Existing Conditions and Land Suitability Maps, EC01 Series of the Drawing Package. As specifically related to the requirements associated with this Plan as required by the ULUR, existing condition are also shown on the Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. 9 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado The Existing Conditions portion of this Plan (Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package) presents existing conditions related to erosion and sediment control and drainage on and immediately adjacent to the Project Site. The drawing also represents the basis for the pre -development hydrologic analysis used in development of this Plan. 1. RIVERS, CREEKS AND FLOODING The Roaring Fork River flows from south to north just west of the Project Site through the adjacent RFC Conservation Easement. The Roaring Fork River is a large perennial river with very large contributing basins to the south. The 160 acre Project Site is located mostly on nearly level river terraces that stand between about 50 to 80 feet above the river. No development is planned directly adjacent to the Roaring Fork River or within the required 35 foot setback under Section 7-203.A of the ULUR except as may be required in association with water and sanitary utilities as described in the plans and reports covering the design of such. The Roaring Fork River's relationship to the Project Site and existing floodplain is depicted on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. Cattle Creek crosses through the Project Site from east to west and roughly divides the property in half. Cattle Creek is a moderately sized perennial stream with a large contributing basin to the east. Cattle Creek joins the Roaring Fork River about mid -way along the western edge of the Project Site within the RFC Conservation Easement. No Development is planned directly adjacent to the Cattle Creek or within the 35 foot setback required by Section 7-203.A of the ULUR except a bridge crossing of Cattle Creek whose abutments are within the setback area and associated utilities crossing. Cattle Creek's relationship to the Project and existing floodplain is depicted on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. The Glenwood Ditch currently diverts water from the Roaring Fork River, south of the Aspen Glen development, to be used for land irrigation. The ditch is piped and enters the Project Site along the southeastern edge of the Project Site paralleling the RFTA Right -of -Way until it reaches Cattle Creek. From that point, it traverses the Project Site in a northwesterly direction and exits the Project Site prior to discharging back to the Roaring Fork River (See Existing Ditch alignment on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package). The current design capacity of the ditch is approximately 50 cfs, of which the REC owns rights to approximately 12 cfs for land irrigation. A portion of the ditch is planned to be relocated as part of the Reclamation Plan (Phase 0, as presented in Appendix U of Impact Report). 2. WETLANDS The wetlands in the vicinity of the Project do not generally extend off the RFC Conservation Easement onto the Project Site except in very isolated areas at the southern end of the Project Site and along Cattle Creek, as presented in the Wetlands Delineation Report (see Appendix G). Wetlands are present along the 10 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado entire length of the Roaring Fork River and Cattle Creek, as shown on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. Special consideration must be given to ensure erosion and sediment control BMPs are properly placed and maintained to minimize indirect impacts to wetlands. While temporary impacts are discussed in the Impact Analysis, no permanent impacts to wetlands are anticipated. 3. GROUNDWATER Groundwater is generally tied to the Roaring Fork River in the area. Hepworth- Pawlek Geotechncial ("HP Geotech") measured groundwater at depths of about 39 to 77 feet in various borings onsite (See Geotechnical Engineering Study, Appendix J of the Impact Analysis for additional information). Shallow groundwater can be expected closer to the Roaring Fork River and Cattle Creek in the lower alluvial terraces on the Project Site. HP Geotech also notes that shallow perched groundwater can occur in association with the substrates that occur on the Project Site during heavy rains where clay- lenses exist, although none are currently documented. 4. TOPOGRAPHY The topography in the area is shown by the contour lines on the Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. These contours represent the existing contours that resulted from the grading activities conducted by Bair Chase in 2005 in association with the Sanders Ranch PUD. The proposed contours are shown on the Reclaimed Condition and Phased Condition, ES02-03 Series of the Drawing Package. The proposed contours will be put in place as part of pre -development reclamation of the Project Site (Phase 0) (See Reclamation Plan, Appendix U of the Impact Analysis). The proposed 160 acre development area is located mostly on nearly level river terraces that stand between about 50 to 80 feet above the Roaring Fork River. The terraces have an average down -valley slope of less than one percent. Steep escarpments separate the original terrace levels, although some have been removed in association with previous grading activities. These escarpments typically have slopes of up to 60 percent. The current topography is significantly modified due to past grading activities and agricultural activities for nearly 80 years before the most recent development activities. Special considerations must be taken in performing construction activities near steep escarpment areas as described in the Hazard Mitigation Plan. B. SPECIAL PLAN CONSIDERATIONS The following sections present special considerations associated with preparing this Plan. Soils and geological conditions on the Project Site are two of the most critical components when preparing the development plan, site grading and drainage, and selecting best management practices (BMPs) to control erosion and sediment releases. 11 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado 1. SOILS The soils have been preliminarily evaluated by HP Geotech. The Geotechnical Engineering Study is provided as Appendix J of the Impact Analysis prepared by 8140 Partners, LLC. The following discussion concerning the soil conditions is summarized from the Geotechnical Engineering Study. The main landforms at the Project Site related to the Project Site's surficial materials include (1) post -glacial alluvial terraces along the Roaring Fork River and Cattle Creek, (2) Pinedale glacial outwash terraces along the Roaring Fork River and related alluvial terraces along Cattle Creek, and (3) coalescing alluvial fans. A small part of the Project Site is located on the post -glacial alluvial terraces and the remaining development area, except the Executive Lot at the south end of the Project Site sits on the Pinedale glacial outwash terraces. The Executive Lot and surrounding open space sit on an alluvial fan. The topsoil was stripped from most of the Project Site and stockpiled in 2005 by Bair Chase in association with the Sanders Ranch PUD approved by Garfield County. The areas stripped of topsoil and stockpile sites are shown on the Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. The previous grading consists of both cut and fill areas. The fill areas are mostly composed of coarse-grained terrace alluvium. The terrace topsoil and upper fine-grained deposits were separated during grading and were placed in the soil stockpiles. The post -glacial terraces are located as two terraces. The lower terrace stands about 5 feet above the river and the higher terrace stands about 13 feet above the river. The alluvium is described as a clast-supported deposit of silty sand with occasional bouldery, pebble and cobble gravel interbedded and often overlain by sandy silt and silty sand. Shallow groundwater is expected to be present in these areas. The proposed development will be located on the higher Pinedale terraces. However, Roaring Fork River utility and Cattle Creek bridge and utility crossings will encounter these post -glacial terrace deposits. The Pinedale outwash terraces along the Roaring Fork River and the associated Cattle Creek terraces occur in several levels that formed at different periods. Grading in 2005 removed all of the mid level terraces. Essentially all of the proposed development within the REC PUD will be on the graded area (originally the fifth and sixth terraces) and on the third, fourth and seventh terrace levels. The alluvium under the Pinedale terraces associated with the Roaring Fork River and Cattle Creek are a clast-supported deposit of rounded gravel, cobbles and boulders in a silty sand matrix. Pedogenetic soil profiles are well developed in the Pinedale terraces. This indicates these surfaces have been stable with respect to erosion and deposition for over about 5,000 years. Soils are excessively cobbly and will be required to be sorted or screened when backfilling trenches. Imported bedding material may be required. Trenching is likely to be difficult and trench walls will require support or be laid back at 2 or 3:1 slopes to prevent failure during construction. 12 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado 2. GEOTECHNICAL CONDITIONS The geotechnical conditions and geologic hazards have been evaluated by HP Geotech. The Geotechnical Engineering Study is provided as Appendix J of the Impact Analysis prepared by 8140 Partners, LLC. Five primary hazards affecting the Project Site were identified in the Geotechnical Report, three of which are described below and were considered in preparing this Plan. These three hazards include evaporite sinkholes, steep terrace escarpments, and debris flows and floods. Their identified locations are shown the Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. The following discussion concerning the geotechnical conditions and geologic hazards is summarized from the Geotechnical Engineering Study. a) Evaporite Sinkholes The entire Project Site is subject to potential sinkhole development as it is underlain by the Eagle Valley Evaporite. The evaporite between Carbondale and about 3 miles south of Glenwood Springs is part of the Roaring Fork diapir which forms the core of the north -trending Cattle Creek anticline. The west limb of the anticline in this part of the Roaring Fork River Valley coincides with the Grand Hogback monocline that marks the western limit of the Carbondale evaporite collapse center. HP Geotech notes that it is uncertain if the regional subsidence and evaporite deformation along the Roaring Fork diapir are still an active geomorphic process or if evaporite deformations have stopped. If still active, present deformations are likely occurring at rates similar to past long-term rates of between 0.5 and 1.6 inches per 100 years. These slow deformation rates should not present a potential risk to buildings and other facilities being considered at the Project Site. b) Steep Terrace Escarpments Steep terrace escarpments that commonly have slopes of about 60 percent and vary from 40 to 80 feet high are present along the Roaring Fork River and the lower reaches of Cattle Creek. These escarpments are potentially unstable and in some cases have been further destabilized due to piping associated with irrigation water from the previous agricultural activities on the Project Site. The escarpments are located along the western most property line and encroach into the RFC Conservation Easement. These areas can contribute to sediment production during rain and flood events or in association with excessive irrigation. c) Debris Flow and Floods With respect to debris flows and floods, HP Geotech notes that coalescing alluvial fans developed at the mouth of the numerous, small drainage basins on the east side of the Roaring Fork River Valley where the ephemeral streams discharge on terrace surfaces. Before construction of SH 82 and development to the east of the highway, the alluvial fan formed a 13 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado continuous apron at the terrace -valley transition. Most of the upper parts of the fans have been removed by grading for these facilities. With the exception of the southernmost portion of the Project Site, the Project Site is not impacted by debris flows. Pedogenetic soil profiles in the fan deposits are mostly weakly. Swell -consolidation tests show that the deposits do not have a high collapse potential (settlement after wetting under a constant load) and are moderately compressible under increased loading after wetting. This indicates that the fans are geologically young landforms and are still potential sites of debris flow and flood deposition. C. HYDROLOGIC AND HYDRAULIC CRITERIA Although Garfield County does not have detailed drainage standards or criteria applicable to urban or suburban development within the ULIUR, UDFCD maintains and distributes the USDCM as a basis for stormwater and drainage design. The USDCM consists of three volumes: (1) Volume 1 and 2 provided guidance for planning and design of drainage channels and hydraulic structures; and (2) Volume 3 provides guidance for the selection and design of stormwater quality best management practices (BMPs). The UDFCD represents one of the most comprehensive drainage criteria manuals available in the State of Colorado and has been used as the basis for the development of local drainage criteria manuals and in drainage design and review processes by a wide variety of municipalities in the State from Grand Junction to Denver to Fort Collins. The USDCM is approved and accepted by the CDPHE-WQCD as a reasonable basis for design. This Plan utilizes the USDCM as the basis for hydraulic design and erosion and sediment control measures to support the design and construction of the REC PUD. The following sections provide the standards and criteria used in preparing this Plan. 1. RAINFALL SOURCE a) Rainfall Input The rainfall input used in developing the runoff characteristics for the Project Site originated from the methodology in NOAA Atlas 2, Volume III for the 2 -year to 100 -year return frequency. The rainfall depths for six events are presented in Table 1. These values were developed using the NOAA methodology. Additional details are presented in Appendix B. Table 1: Rainfall Depth by Return Period (inches) Storm Duration (Minutes) Rainfall Depth (inches) by Return Period 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year 5 0.18 0.25 0.30 0.37 0.43 0.49 10 0.27 0.39 0.47 0.57 0.66 0.75 15 0.35 0.50 0.60 0.72 0.84 0.95 30 0.48 0.69 0.83 1.00 1.17 1.32 60 0.61 0.87 1.05 1.27 1.48 1.67 14 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado b) Runoff Methodology For the preliminary sizing of detention basins, culverts, conveyance channels and other drainage structures, the rational method was used. All basins within the Project Site are less than 90 acres. The portions of the developed areas planned for higher densities are more appropriately modeled as small urban watersheds. Therefore the rational method is appropriate for this application as well. Intensity -Duration -Frequency curves for the Project Site have been developed and are shown in Appendix C, Exhibit 1. The initial time of concentration for each basin is determined by the following equation: Where: T, = 1.8 x [(1.1-C5)L1/2]/S1/3 T; = the initial time of concentration in minutes C5 = the 5 -year runoff coefficient L = the length of the flow path in feet (not to exceed 300 feet for urban and 500 feet for rural) S = the slope of the flow path in percent The channel time of concentration is determined by the velocity method outlined in Figure 7.2 of the CDOT Drainage Design Manual. The velocity is determined by the following equation: V = kS1/2 Where: V = the velocity in feet per second K = the land use/land cover factor S = the slope of the flow path in percent The time of concentration for channel flow is determined by the following equation: Tt = L/(60V) Where: Tt = the channel time of concentration in minutes 15 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado L = the length of the flow path in feet V = the average velocity in feet per second D. HYDRAULIC CRITERIA 1. CONVEYANCE CHANNELS Conveyance channels are used in the REC PUD to collect and direct concentrated surface water flows towards permanent BMPs (i.e. detention and storm water quality basins). The specific criteria used to plan and preliminarily design these channels, and associated culverts, were obtained from the following: • Open channel conveyance - USDCM, Volume 1, Section 3.0 • Grass swales - USDCM, Volume 3, Section 2.0 • Culverts - USDCM, Volume 2, Chapter 9 2. STORM SEWERS Storm sewers and inlets will be designed, at a minimum, to convey the 10 -year storm, with pipes 80 percent full. The specific criteria used to plan and preliminarily design these structures were obtained from USDCM, Volume 1, Chapter 6. Based on the preliminary information and USDCM criteria, all storm sewers are and may be designed and constructed to meet this standard. 3. ROAD FLOWS Flow in roads should be contained within the right-of-way for the 100 -year storm and smaller events must be kept to a coverage area and depth that ensures the roads remain passable during these occurrences. Based on the preliminary information, the drainage and road system is and may be designed to meet this requirement in coordination with the emergency runoff conveyance discussed below. 4. EMERGENCY RUNOFF CONVEYANCE During large storm events (i.e. 100 -year), the conveyance systems reach capacity and, in some cases, can become overloaded. During these events, the open space areas and common areas will work in coordination with the constructed systems to safety convey large storm event flows through the Project Site without causing significant damage to structures or potential for loss of life. Adequate space to accommodate conveyance is available and detailed grading can be accommodated. Details will be determined during Final Design. 16 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado IV. GRADING AND DRAINAGE PLAN A. OVERALL CONCEPT The overall grading concept associated with the Project was developed based on the following primary goals: • Reclaim/restore the overall site from previously uncompleted golf course related grading and topsoil removal activities; and • Facilitate the development of the REC PUD while seeking to create a separation between human activity and adjoining wildlife conservation areas. Concurrently, the drainage concept associated with the Project was developed based on the following primary goals: • Manage surface water by conveying it through the Project Site towards outfalls located on Cattle Creek and the Roaring Fork River with limited ground infiltration; and • Manage surface water quality through the use of natural systems, where appropriate and consistent with geologic and soil conditions. The following sections present further detail about the proposed grading and drainage plan and comparisons of the pre- and post -development conditions based on the subbasins presented on the Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. 1. GRADING AND DRAINAGE The northern portion of the Project Site was graded to generally direct surface water via channels, roads, and storm sewers to the southwest, while the southern portion of the Project Site was graded to generally direct surface water via channels, roads and storm sewers to the northwest. Three primary subbasins were identified and used for drainage calculations (see Appendix D, Exhibit 1). Understanding the planned characteristics (i.e. layout, slopes, density, and land use) of each subbasin assists in selecting the specific methodologies to be used for management of stormwater quantity and quality. For purposes of developing preliminary estimates of flow, a brief description of each subbasin is provided below: • North Basin 1 (P1) - Open space areas with passive recreation • North Basin 2 (P2) - Urban "clustered" residential development • South Basin 1 (P3) - Urban "clustered" residential development A runoff coefficient based on USDCM recommendations was selected for each subbasin and is provided in Table 2 as discussed in Section IV.B.1 of this Plan. 17 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado 2. OFF-SITE BASINS Runoff from offsite basins to the Project Site is very limited due to SH 82 running paralleling the east side of the southern end of Project Site and the RFTA Right -of -Way paralleling the east side of the north end of the Project Site. These two regional features intercept much of the offsite flow that would otherwise naturally drain onto the Project Site from the east. Other than very localize drainage captured by inlets and directed west via culverts from near the highway and the 43 acres parcel north and east of the Project Site of which only 50 percent of the area currently outfalls to the Project Site (OS -1), the offsite drainage is generally picked up by Cattle Creek prior to entering the Project Site. Therefore, offsite basins have little impact on the Project Site. The OS -1 basin is assumed to contain 23.6 acres of contributing area, and 50% impervious under post development conditions. No detention on the OS -1 basin is assumed to occur post -development. 3. SURROUNDING LAND USES As shown on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package, the surrounding land uses range from vacant to small mixed commercial, a trailer park, and rural residential. None of these developments provide direct runoff to the Project Site nor do they have existing facilities that would be affected by the planned grading and drainage activities. The significant adjoining land uses with respect to drainage are associated with the RFTA Right -of -Way, SH 82, Cross Creek and the Roaring Fork River. 4. WATER QUANTITY AND QUALITY STORAGE There will be an increase in peak runoff rates from the Project Site relative to historic flows, as presented in part B below. However, given the size of the upstream basins (i.e. very small as compared to the basins contributing flows to Cattle Creek and the Roaring Fork River) and proximity of the Project Site to the outfall for Cattle Creek and Roaring Fork basins, it is being proposed that water quantity storage (i.e. runoff detention) not be provided in accordance with Section 7-207.C.1 of the ULUR. This is a modification from the existing County standards, but the planned approach has technical merit based on the particular site conditions present. The primary reason for this request is that the Project Site is located at the confluences of the two major perennial waterways and detention of surface runoff at historic rates provides little value or could even be detrimental to these waterways since it delays the releases from the Project Site in a manner that could coincide with the peaks flows from larger contributing basins up stream (i.e., adding to the magnitude of the peak flow). If these larger stormwater volumes are not detained, the peak flows generated from the Project Site will be released prior to these other peaks entering the areas. Furthermore, stormwater runoff from the Project Site does not discharge to or impact adjacent properties or downstream drainage structures. Should the County believe that quantity storage in addition to quality storage is required, the storage volumes for both quantity and quality are provided herein and the area necessary to store this increased volume is available within the locations 18 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado identified on the engineering plans to accommodate the volumes without any impact to lots within the Project. B. SPECIFIC DETAILS 1. ONSITE BASINS The overall subbasin characteristics are discussed above. For purposes of developing preliminary estimates of flows, a runoff coefficient based on standard return periods for each subbasin is provided in Table 2 based on USDCM recommendations. Table 2: Runoff Coefficient (C) by Return Period Basin Percent Impervious Return Period 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year P1 25 0.09 0.16 0.23 0.29 0.32 0.35 P2 40 0.19 0.25 0.30 0.35 0.38 0.41 P3 30 0.13 0.19 0.25 0.31 0.34 0.37 Based on the subbasin characteristics presented, the calculated peak flows for pre -development conditions at the outfalls are shown in Table 3. Table 3: Outfall Peak Flows by Return Period - Pre Development Conditions Basin Outfall Peak Flows (cfs) by Return Period 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year P1 0.00 0.00 0.97 2.71 4.08 6.40 P2 0.00 0.00 2.11 5.90 8.91 13.86 P3 0.00 0.00 3.36 9.38 14.13 22.14 OS -1 0.00 0.00 1.10 3.06 4.62 7.17 Based on the subbasin characteristics presented, the calculated peak flows for post -development conditions at the outfalls are shown in Table 4. Detailed routing of smaller subbasins within areas of higher densities will be performed during final design at time of Final Plat. 19 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado Table 4: Outfall Peak Flows by Return Period - Post Development Conditions Basin Outfall Peak Flows (cfs) by Return Period 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year 100 -Year P1 1.27 3.08 5.29 7.75 9.65 13.23 P2 9.62 17.30 24.78 33.62 41.17 55.69 P3 8.27 16.50 25.88 37.38 46.22 63.05 05-1 7.15 11.74 16.35 21.71 25.73 34.56 2. MAJOR DRAINAGEWAYS a) Roaring Fork River The Roaring Fork River flows from the south to north along the western edge of the Project Site. The existing floodplain is depicted on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. Flows at various return periods (or recurrence intervals) as shown in Table 5. A single Roaring Fork River crossing location is proposed in association with the Project. The crossing would include the installation of water and sewer utilities. Based on existing floodplain information, negligible permanent impact to the base flood elevations is expected. However, the installation of the utilities across the river will have temporary wetland and water quality impacts during construction. Discussions with the U.S. Army Corp of Engineers ("ACOE") relative to wetland impacts and associated permitting have been initiated and will be furthered as part of final design in association with first Final Plat. Table 5: Roaring Fork Flood Flows (cfs) by Return Period Return Periods (Years) Flows Upstream of Confluence w/ Cattle Creek (cfs) 10 12,000 50 17,000 100 19,200 500 25,000 b) Cattle Creek Cattle Creek bisects the property and runs in a northwesterly direction. The existing floodplain is depicted on Erosion and Sediment Control Plan - Existing Conditions, ES01 Series of the Drawing Package. Flows at various return periods (or recurrence intervals) as shown in Table 6. A single Cattle Creek crossing location is planned as part of the Project. The crossing will include both the construction of a vehicular/pedestrian bridge and installation of water, sewer and dry utilities. Based on existing floodplain information, negligible permanent impact to the base flood elevations is expected. However, the installation of the utilities across the creek will have temporary wetland and water quality impacts during construction. Discussions with the ACOE relative to wetland impacts and associated 20 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado permitting have been initiated and will be furthered as part of final design in association with first Final Plat. Table 6: Cattle Creek Flood Flows (cfs) by Return Period Return Periods (Years) Flows Upstream of Confluence w/ Roaring Fork River (cfs) 10 2,100 50 2,550 100 2,850 500 4,400 c) Glenwood Ditch The Glenwood Ditch currently diverts water from the Roaring Fork River, south of the Aspen Glen development, to be used for land irrigation. The ditch is piped and enters the Project Site along the southeastern edge of the Project Site paralleling the RFTA Right -of -Way until it reaches Cattle Creek. From that point, it traverses the Project Site in a northwesterly direction until it exits the Project Site. The current design capacity of the ditch is approximately 50 cfs, of which the REC owns rights to approximately 12 cfs for land irrigation. A portion of the ditch is planned to be relocated as part of the Reclamation Plan (Phase 0). 3. WATER QUANTITY AND QUALITY STORAGE FACILITIES Based on the subbasin characteristics presented, calculated peak flows for pre - and post -development conditions at the outfalls were developed. Table 7 shows a comparison of these peak flows for each subbasin, the increase created by the post -development conditions, and the structure used to mitigate increased flows (if deemed necessary) and provide storage for the WQCV. Water quantity and quality storage facilities are designed based on the Rational Method for calculating runoff, the FAA methodology for calculating detention volumes, and Urban Drainage and Flood Control District's Storm Drainage Criteria Manual for calculating water quality capture volume. These calculations are shown in Appendix E. The drainage areas, historic 100 -year inflow, and developed 100 -year inflow for the ponds are shown in Table 7. Storage sizes are based on the developed and historic flows shown in Table 7. The rainfall intensities used in the calculations are from the NOAA method, and are based on the historic and developed time of concentrations. The runoff coefficients were estimated at 0.05 (10 -yr) and 0.2 (100 -yr) for pre -development conditions and 0.23 (10 -yr P1), 0.30 (10 -yr P2), 0.25 (10 -yr P3), 0.35 (100 -yr P1), 0.41 (100 - yr P2) and 0.37 (100 -yr P3) for post -development conditions, respectively. Inputs for calculating the historic and developed flows are shown in Appendix E. 21 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado Table 7: Comparison of Pre- and Post -Development Outfalls Basin Outfalls (cfs) by Return Period Mitigation Pre -Development Post -Development Increase 10 -Year 100 -Year 10 -Year 100 -Year 10 -Year 100 -Year P1 0.97 6.40 5.29 13.23 4.32 6.83 NP1 P2 2.11 13.86 24.78 55.69 22.67 41.83 NP2 P3 3.36 22.14 25.88 63.05 22.52 40.91 SP1 OS -1 1.10 7.17 13.65 34.56 12.55 27.39 NP2/NP1 As stated above, this Plan does not include water storage for the purposes of runoff detention. However, Table 8 presents storage estimations developed for both water quantity (i.e. increased runoff) and quality (i.e. WQCV) should the County deem the combined storage as being required. To address the total combined storage, NP1 would be slightly enlarged to accommodate additional flow redirected from NP2, therefore, lessening the depth of NP1 to approximately 6 feet and increasing the depth of NP1 to approximately 6 feet. The planned approach of allowing the post -development runoff to outfall without detention is being proposed for the reasons stated above (Section IV.A.4) and not because it could not be accommodated. Rather, from the information available, it appears more technically appropriate to allow the peak flows from this Project Site to enter the Roaring Fork River prior to other peak flows generated higher in the contributing basin, thereby reducing the overall magnitude of the runoff peak experienced by the Roaring Fork River. Table 8: Estimated Storage Facility Volumes Storage Facility Total Required Combined Storage (cf) WQCV Only Required Storage (cf) Total Combined Storage Area (sf) Total Combined Storage Depth (ft) WQCV Only Storage Depth (ft) NP1 29,295 4,817 10,548 2.78 0.46 NP2 200,628 28,836 21,248 9.44 1.36 SP1 253,447 34,708 66,404 3.82 0.52 V. EROSION AND SEDIMENT CONTROL A. OVERALL CONCEPT Managing surface water quality requires a two pronged approach to ensure the release of surface water from the Project Site meets County requirements. The first prong requires the management of the Water Quality Capture Volume (WQCV) from impervious areas. The WQCV or "first flush" as it is sometimes referred to, contains the majority of the pollutants that accumulate between rain events. Managing the WQCV enhances stormwater quality prior to discharge to the receiving water (i.e. Cattle Creek and the Roaring Fork River). This Plan proposes the use of standard methodologies for 22 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado management of the WQCV, which includes the use of permanent BMPs such as water quality storage facilities and conveyance channels. The second prong requires erosion and sediment control before, during, and after site development occurs. Controlling the release of sediment and reducing surface erosion requires the implementation of temporary and permanent, as well as structural and non-structural BMPs. The implementation of BMPs target either minimizing the release before it happens (i.e. vegetating of steep slopes) or capturing the release before discharge (i.e. sediment basin). This Plan proposes an aggressive approach to controlling erosion and sediment release during construction efforts through the installation and maintenance of USDCM recommended BMPs (i.e. silt fence, straw waddles, vehicle tracking controls, and culvert inlet and outlet controls). For purposes of clarity and coordination, the engineering drawings supporting this Plan (Series ES01-04 of the Drawing Package) have been broken up into four conditions, presenting the following information: • Existing Conditions: existing topography, areas of slopes greater than 20 percent, location of existing structures, waterbodies, hydrologic features, and drainage structures (Series ES01) • Reclaimed Conditions: interim topography, areas of slopes greater than 20 percent, and areas of revegetation (Series ES02) • Phased Conditions: probable locations of soil stockpiles and processing areas, equipment and materials storage areas, temporary roads, phased erosion control measures (temporary), and construction schedule (Series ES03) • Final Conditions: final topography, extent and grades of building sites, driveway grades, probable snow storage areas, and final erosion control measures (permanent) (Series ES 04) Each of the conditions is further explained in the following sections, except for the Existing Conditions which was previously discussed. The Reclaimed and Phased Conditions portions of this Plan are the basis for the required Stormwater Management Plan (SWMP) application to be submitted to the CDPHE as part of subsequent design efforts and prior to construction activities. See Appendix F for a draft copy of the application to be provided prior to the pre -development reclamation (Phase 0) and initiation of development construction. B. RECLAIMED CONDITIONS Although the Reclamation Plan (Appendix U of the Impact Analysis) includes relocating the RFTA trail and Glenwood Ditch, interim grading, and water storage facility construction, the primary focus of the Reclaimed Conditions portion of this Plan is to present the preliminary requirements for vegetation of disturbed areas with either permanent or temporary vegetation (See Erosion and Sediment Control Plan - 23 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado Reclaimed Conditions, ES02 Series of the Drawing Package), as appropriate. The four primary approaches/schedules for vegetation activities include: • Open Space Areas: Permanent vegetation of the western portion of the Project Site, nearest the RFC Conservation Easement (see planting schedule in the Revegetation Plan, Appendix B of the Reclamation Plan and Open Space Plan, OS01 Series of the Drawing Package) ■ Common Areas: Temporary and permanent vegetation of the outer perimeter of the Project Site and temporary vegetation of the edges of the RFC Conservation Easement along Cattle Creek where community orchards and gardens are planned (see planting schedule in the Landscape Plan, LA01-05 Series of the Drawing Package) • RFTA Open Space Easement: Permanent vegetation within 50 foot open space easement as required by RFTA based on requirements of the current agreement (see planting schedule in the Landscape Plan, LA01- 05 Series of the Drawing Package) • Development Areas: Temporary vegetation (including a possible onsite nursery) in areas planned for future development (see planting schedule in the Revegetation Plan, Appendix B of the Reclamation Plan) As presented on the Reclaimed Conditions portion of this Plan (Erosion and Sediment Control Plan - Reclaimed Conditions, ES02 Series of the Drawing Package) and further presented on the Reclamation Plan (Reclamation Plan, RPO1 Series of the Drawing Package), temporary erosion and sediment control BMPs (structural and non-structural) will also be installed and maintained throughout this Reclaimed Condition process. As required by the County, special considerations will be given to soil stockpile and processing areas and equipment and materials storage areas ensuring further protection is provided and sediment releases (including dust) are controlled. Specific procedures for spill control will be further detailed during the final design process. However, at a minimum, all chemical stored onsite will be properly containerized and secondary containment provided as necessary. C. PHASED CONDITIONS As shown on the schedule provided, the Phased Conditions will occur over a 7 year period (Erosion and Sediment Control Plan - Phased Conditions, ES03 Series of the Drawing Package). During that time, up to eleven different filings, consisting of an average of 50 units, will be final designed and submitted for Final Plat approvals. As shown, the construction activities will remain "liquid" and the erosion and sediment control measures will be modified, as necessary, to support the actions being performed at that time. In addition, until the disturbed areas are fully reclaimed (i.e. the vegetation is matured as specified) or the installed structure (i.e. culverts or storm sewers) is performing as specified, the BMPs installed with that particular phase of construction will continue to be maintained. As required by the County, special considerations will be given to soil stockpile and processing areas and equipment and materials storage areas ensuring further protection is provided and releases are controlled. 24 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado As presented on the Erosion and Sediment Control Plan - Phased Conditions, ES03 Series of the Drawing Package, temporary erosion and sediment control BMPs (structural and non-structural) will be installed and maintained throughout this Phased Conditions process. As required by the County, special considerations will be given to soil stockpile areas and equipment and materials storage areas ensuring further protection is provided and sediment releases (including dust) are controlled. Specific procedures for spill control will be further detailed during the final design process. However, at a minimum, all chemical stored onsite will be properly containerized and secondary containment provided as necessary. D. FINAL CONDITIONS As the Project Site reaches development completion, the Final Conditions portion of this Plan will be implemented (See Erosion and Sediment Control Plan - Final Conditions, ESO4 Series of the Drawing Package). The buildout conditions include final grading of building sites and driveways and the implementation of any remaining permanent erosion and sediment control BMPs and the removal of all temporary BMPs associated with development construction. As presented above, the primary permanent BMP is the construction of the three storage facilities during the reclamation phase (Phase 0). Other permanent BMPs such as channel vegetation and structures inlet and outlet protection will also be installed and maintained as part of overall community maintenance. Maintenance of the permanent structures has been planned for and easements provided to allow for continued access (See PUD Plan, PUD01-03 Series of the Drawing Package). In addition, an overall snow storage management program will be put into place to protect against the release of salt or sands used for traction from stored snow into drainage outfalls (i.e. Cattle Creek and the Roaring Fork River). As in all developments, the Project Site will continue to change to meet the ever changing needs of the community. As these changes occur and should land disturbance be required, general temporary erosion and sediment control BMPs should be installed to continue the protection of the surrounding surface water quality. At a minimum, the following BMPs should be installed, but specific BMPs for particular situations may also be required: • Install silt fence along the perimeter of disturbance area. • Install vehicle traction control measures where off-road vehicles enter paved areas. • Make water available for dust control and the removal of mud from equipment. • Cover all stockpiles soils materials. As indicated above, specific BMPs particular to a situation may be required. In addition, proper management of equipment and notifications to the community are also recommended. 25 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado VI. COST ESTIMATE AND METHOD OF FINANCING A cost analysis and estimate will be provided for erosion and sediment control under separate cover in conformance with Section 6-301C.8.r.(3) of the ULUR at the time of and in association with each Subdivision Application for Final Plat. The cost estimate shall include estimates for detailed erosion and sediment control as necessary to support the development of the lots being proposed for creation within the boundaries of the Final Plat being submitted for review. Based on the preliminary design submitted for review in association with the current rezoning and preliminary plan application supported by this Plan, preliminary costs have been developed and reviewed by 8140 Partners, LLC. These costs have been determined to be reasonable and support the feasibility of implementing the above proposed erosion and sediment control as part of the Project. Preliminary cost estimates are viewed by Carbondale Investments, LLC ("CI") as proprietary information and of limited or no value to the rezoning and preliminary plan review and approval process since no construction is specifically allowed nor is any construction security required by any such approval granted by Garfield County. VII. LIST OF REFERENCES Colorado Water Conservation Board, "Colorado Floodplain and Stormwater Criteria Manual," 2006. Federal Emergency Management Agency (FEMA), "Flood Insurance Study - Garfield County, Colorado" 1986. (Panel 1465 of 1900 -No. 080205 1465B) U.S. Army Corps of Engineers, "Flood Frequency Analysis Program" (FFA version 3.1). U.S. Department of Commerce, National Oceanic and Atmospheric Administration, "NOAA Atlas 2, Precipitation -Frequency Atlas of the Western United States, Volume III", 1973. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria Manual Volumes 1-3." 26 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX A: VICINITY MAP AND PROJECT SITE DRAWINGS App. A-1 BITS\MISC REPOPT FIGURES \PUD-VICMAP.DWG N 5 000 0 5.000 10 000 SCALE IN FEET Owner/Developer: RiVentige COLORADO Carbondale Investments, LLC 7999 HWY 82 Carbondale, CO 81623 Phone No: 970.456.5325 Title: VICINITY MAP Prepared by: 8140 Partners, LLC Date: 12/01/10 Exhibit: App. A-2 BITS\MISC REPORT FIGURES \PUD -L 02 PRELIM PLAT\ENGINEERING & DESIGN\CAC > o a J w `LTA67, w= OU Q Z N I- I- J o 0 0 E d a s LEGAL DESCRIPTION - PARCEL A (NORTH PARCEL) - RIVERS EDGE PUD A TRACT OF LAND SITUATED IN THE EAST HALF OF SECTION 12, TOWNSHIP 7 SOUTH, RANGE 89 WEST, AND IN THE WEST HALF OF SECTION 7, TOWNSHIP 7 5011TH, RANGE 88 WEST OF THE 6TH PRINCIPAL MERIDIAN, COUNTY OF GARFIELD, STATE OF COLORADO, BEING MORE PARTICULARLY DESCRIBED AS FOLLOWS: BEGINNING GARFIELD COUNTY SURVEYOR'S 2 1/2" BRASS, FOUND IN PLACE, AND CORRECTLY MARKED AS THE SOUTHEAST CORNER OF SAID SECTION 7, THENCE S 492915" E A DISTANCE OF 5479.54 FEET TO THE TRUE POINT OF BEGINNING; THENCE, 5 89'43'30" E A DISTANCE OF 1005.44 FEET TO A POINT ON THE WESTERLY LINE OF THE ROARING FORK TRANSIT AUTHORITY TRANSPORTATION CORRIDOR EASEMENT; THENCE, ALONG THE WESTERLY LINE OF SAID EASEMENT S 1038'52" E A DISTANCE OF 2644.53 FEET; THENCE, 494.34 FEET ALONG THE ARC OF A CURVE TO THE RIGHT, HAVING A RADIUS OF 2815.00 FEET, A CENTRAL ANGLE OF 10'03'42 AND SUBTENDING A CHORD BEARING OF S 14'37'01" E A DISTANCE OF 493.70 FEET; THENCE, 5 09'3909" E A DISTANCE OF 120.78 FEET; THENCE, DEPARTING THE WESTERLY LINE OF SAID EASEMENT N 6506'14' W A DISTANCE OF 6045 FEET; THENCE, N 49'54'10" W A DISTANCE OF 64.72 FEET; THENCE, N 49'54'10" W A DISTANCE OF 86.97 FEET; THENCE, N 48'11'10" W A DISTANCE OF 54.30 FEET; THENCE, N 56'4127" W A DISTANCE OF 123.97 FEET, THENCE, N 804724" W A DISTANCE OF 93.00 FEET; THENCE, N 29'3931" W A DISTANCE OF 119.58 FEET; THENCE, N 78'00'43" W A DISTANCE OF 3384 FEET; THENCE, S 7041'40" W A DISTANCE OF 37.80 FEET, THENCE, S 2757'52" W A DISTANCE OF 56.05 FEET; THENCE, 5 59'31'57" W A DISTANCE OF 4O48 FEET; THENCE, N 8732'35" W A DISTANCE OF 28.23 FEET; THENCE, N 59'07'03" W A DISTANCE OF 95.71 FEET, THENCE, N 71'20'44" W A DISTANCE OF 85.73 FEET; THENCE, N 36'4910" W A DISTANCE OF 93.22 FEET; THENCE, N 25'39'22" W A DISTANCE OF 181.92 FEET; THENCE, N 65'10'24" W A DISTANCE OF 98.43 FEET; THENCE, 5 85'02'33" W A DISTANCE OF 52.20 FEET; THENCE, 5 593952" W A DISTANCE OF 39.34 FEET; THENCE, S 2149'33" W A DISTANCE OF 42.96 FEET; THENCE, 5 37'27'43" E A DISTANCE OF 21.60 FEET; THENCE, N 7002'57" W A DISTANCE OF 89.66 FEET; THENCE, S 7124'18" W A DISTANCE OF 70.95 FEET; THENCE, N 88'5939" W A DISTANCE OF 55.55 FEET; THENCE, 5 84'28'58" W A DISTANCE OF 49.93 FEET; THENCE, N 14'22'48" E A DISTANCE OF 68.20 FEET; THENCE, N 0511'46" W A DISTANCE OF 77.59 FEET, THENCE, N 192005" E A DISTANCE OF 10,82 FEET; THENCE, N 275040" E A DISTANCE OF 44.14 FEET; THENCE, N 10134'58" E A DISTANCE OF 35,11 FEET; THENCE, N 08'5951" E A DISTANCE OF 47.16 FEET; THENCE, N 03'48'08" E A DISTANCE OF 36.48 FEET; THENCE, N 0440'52" E A DISTANCE OF 71 03 FEET; THENCE, N 0037'51" E A DISTANCE OF 5466 FEET; THENCE, N 202914" W A DISTANCE OF 63.68 FEET; THENCE, N 370944" W A DISTANCE OF 6105 FEET; THENCE, N 261129" W A DISTANCE OF 55,52 FEET; THENCE, N 391736" W A DISTANCE OF 44.36 FEET; THENCE, N 5011'32" W A DISTANCE OF 37.73 FEET; THENCE, N 5054'48" W A DISTANCE OF 54.16 FEET; THENCE, N 87'51'30' W A DISTANCE OF 3697 FEET; THENCE, N 57'33'47" W A DISTANCE OF 65.70 FEET; THENCE, N 81'56'22" W A DISTANCE OF 8502 FEET; THENCE, N 0711'29" W A DISTANCE OF 158,65 FEET; THENCE, N 355141" W A DISTANCE OF 41.30 FEET; THENCE, N 574903" W A DISTANCE OF 24.70 FEET; THENCE, N 2951'45" W A DISTANCE OF 20999 FEET; THENCE, N 11'50'37" W A DISTANCE OF 3382 FEET; THENCE, N 41'0046" E A DISTANCE OF 78.19 FEET; THENCE, N 0629'01" W A DISTANCE OF 117.20 FEET; THENCE, N 20'05'27" W A DISTANCE OF 94.24 FEET; THENCE, N 11'3203" W A DISTANCE OF 63.83 FEET; THENCE, N 07'57'46" W A DISTANCE OF 141.45 FEET; THENCE, N 005914" E A DISTANCE OF 5976 FEET; THENCE, N 1917'44" W A DISTANCE OF 91.04 FEET; THENCE. N 4141'59" W A DISTANCE OF 134.55 FEET; THENCE, N 192949" W A DISTANCE OF 74.18 FEET; THENCE, N 103306" W A DISTANCE OF 43.27 FEET; THENCE, N 203901" W A DISTANCE OF 72.23 FEET; THENCE, N 0016'30" E A DISTANCE OF 217.77 FEET; THENCE, N 0116'30" E A DISTANCE OF 312.94 FEET TO THE POINT OF BEGINNING, CONTAINING AN AREA OF 73.003 ACRES, MORE OR LESS. THE NAME AND ADDRESS OF THE PERSON WHO CREATED THIS LEGAL DESCRIPTION LS: JEFFREY ALLEN TUTTLE, P.LS. 33638 727 BLAKE AVENUE GLENWOOD SPRINGS, COLORADO 81601 LEGAL DESCRIPTION - PARCEL C (SOUTHEAST PARCEL) - RIVERS EDGE PUD A TRACT OF LAND SITUATED IN THE SOUTHWEST QUARTER OF SECTION 7, TOWNSHIP 7 SOUTH, RANGE 88 WEST OF THE 516TH PRINCIPAL MERIDIAN, COUNTY OF GARFIELD, STATE OF COLORADO, BEING MORE PARTICULARLY DESCRIBED AS FOLLOWS: BEGINNING AT A POINT ON THE WESTERLY RIGHT OF WAY UNE OF COLORADO STATE HIGHWAY 82, WHENCE A 2 1/2" BRASS CAP, FOUND IN PLACE AND PROPERLY MARKED AS THE SOUTHEAST CORNER OF SAID SECTION 7, BEARS S 7901'43" E A DISTANCE OF 2054.18 FEET; THENCE, ALONG SAID WESTERLY RIGHT OF WAY LINE N 003910" W A DISTANCE OF 188.14 THENCE, 282.60 FEET ALONG THE ARC OF A CURVE TO THE LEFT HAVING A RADIUS OF 2915.00 FEET, A CENTRAL ANGLE OF 5'33'17" AND SUBTENDING A CHORD BEARING OF N 12'21'49" W A DISTANCE OF 28249 FEET; THENCE, DEPARTING SAID RIGHT OF WAY UNE S 90'0000" E A DISTANCE OF 49.74 FEET; THENCE, S 06'01'00" E A DISTANCE OF 202.70 FEET; THENCE, 5 0434'58" E A DISTANCE OF 260.70 FEET TO THE POINT OF BEGINNING, CONTAINING AN AREA OF 0.234 ACRES, MORE OR LESS. THE NAME AND ADDRESS OF THE PERSON WHO CREATED THIS LEGAL DESCRIPTION 15: JEFFREY ALLEN TUTTLE, P.L.S, 33638 727 BLAKE AVENUE GLENWOOD SPRINGS, COLORADO 81601 Owner/Developer: RiVerEdge COLORADO Carbondale Investments, LLC 7999 HWY 82 Carbondale, CO 81623 Phone No: 970.456.5325 LEGAL DESCRIPTION - PARCEL 8 (SOUTH PARCEL) - RIVERS EDGE PUD A TRACT OF LAND SITUATED IN THE EAST HALF OF SECTION 12, TOWNSHIP 7 SOUTH, RANGE 89 WEST, AND IN THE WEST HALF OF SEC8ON 7 AND IN THE NORTH HALF OF SECTION 18, TOWNSHIP 7 SOUTH, RANGE 88 WEST OF THE 6TH PRINCIPAL MERIDIAN, COUNTY OF GARFIELD, STATE OF COLORADO, BEING MORE PARTICULARLY DESCRIBED AS FOLLOWS: BEGINNING AT A POINT ON THE WESTERLY RIGHT OF WAY LINE OF COLORADO STATE HIGHWAY 82, WHENCE A 2 1/2" BRASS CAP, FOUND IN PLACE AND CORRECTLY MARKED A5 THE SOUTHEAST CORNER OF SAID SECTION 7, BEARS S 78'49'20" E A DISTANCE OF 2150.14 FEET; THENCE, ALONG SAID RIGHT OF WAY LINE S 09'35'09 E A DISTANCE OF 401.79 FEET; THENCE, S 0913509 E A DISTANCE OF 1545.87 FEET; THENCE, 626.05 FEET ALONG THE ARC OF A CURVE TO THE LEFT HAVING A RADIUS OF 1482.50 FEET, A CENTRAL ANGLE OF 24111'44" AND SUBTENDING A CHORD BEARING OF 5 21'41'02" E A DISTANCE OF 621,41 FEET; THENCE, 5 33146'54 E A DISTANCE OF 387.28 FEET; THENCE, 294.32 FEET ALONG THE ARC OF A CURVE TO THE RIGHT, HAVING A RADIUS OF 2815,00 FEET, A CENTRAL ANGLE OF 559'26" AND SUBTENDING A CHORD BEARING OF 5 30'4711 E A DISTANCE OF 294.19 FEET; THENCE, DEPARTING SAID RIGHT OF WAY LINE N 89'5016 W A DISTANCE OF 218.07 FEET; THENCE, N 40'2030 W A DISTANCE OF 6838 FEET; THENCE, S 87'28'29 W A DISTANCE OF 36.35 FEET; THENCE, S 8052'12 W A DISTANCE OF 10.80 FEET; THENCE, N 58'27'19 W A DISTANCE OF 41.45 FEET; THENCE, N 29'51'31 W A DISTANCE OF 8.28 FEET; THENCE, N 2116'24 W A DISTANCE OF 25.22 FEET; THENCE, N 69'00'53 W A DISTANCE OF 9.87 FEET; THENCE, S 87'31'44 W A DISTANCE OF 22.60 FEET; THENCE, N 57'25'01 W A DISTANCE OF 17,28 FEET; THENCE, N 50'09'49 W A DISTANCE OF 26.07 FEET; THENCE, N 46'21'12 W A DISTANCE OF 9.99 FEET; THENCE, N 44'28'05 W A DISTANCE OF 21.45 FEET; THENCE, N 55'50'08 W A DISTANCE OF 4805 FEET; THENCE, N 56'25'40 W A DISTANCE OF 49.94 FEET, THENCE, N 68'12'23 W A DISTANCE OF 36.45 FEET; THENCE, N 46'5104 W A DISTANCE OF 55.18 FEET; THENCE, N 6949'21 W A DISTANCE OF 25.14 FEET; THENCE, N 4041'50 W A DISTANCE OF 7878 FEET; THENCE, N 30'26'40 W A DISTANCE OF 24.58 FEET; THENCE, N 2947'01 W A DISTANCE OF 30.08 FEET; THENCE, N 18'11'39 W A DISTANCE OF 34.61 FEET; THENCE, N 3958'21 W A DISTANCE OF 29.32 FEET; THENCE, N 21'59'14 W A DISTANCE OF 27.50 FEET; THENCE, N 30'16'07 W A DISTANCE OF 22.97 FEET; THENCE, N 2941'38 W A DISTANCE OF 169.44 FEET; THENCE, N 41'1739 E A DISTANCE OF 82.61 FEET; THENCE, N 38'3752 E A DISTANCE OF 15.89 FEET; THENCE, N 3126'44 W A DISTANCE OF 262.40 FEET; THENCE, N 57'58'09 W A DISTANCE OF 102.47 FEET; THENCE, N 504031 W A DISTANCE OF 105.38 FEET; THENCE, N 55158'11 W A DISTANCE OF 126.13 FEET; THENCE, N 56'14'57 W A DISTANCE OF 118.42 FEET; THENCE, N 49'16'04 W A DISTANCE OF 136.33 FEET; THENCE, N 4130'51 W A DISTANCE OF 150,05 FEET; THENCE, N 32'49'55 W A DISTANCE OF 102.14 FEET; THENCE, N 37144'19 W A DISTANCE OF 552.12 FEET;. THENCE, N 18'10'02 W A DISTANCE OF 47.26 FEET; THENCE, N 2758'19 W A DISTANCE OF 109.20 FEET; THENCE, N 3901'36 W A DISTANCE OF 71.09 FEET; THENCE, N 41132147 W A DISTANCE OF 152.23 FEET; THENCE, N 40'2724 W A DISTANCE OF 33E82 FEET; THENCE, N 642053 W A DISTANCE OF 34.06 FEET; THENCE, N 4900'36 W A DISTANCE OF 52.42 FEET; THENCE, N 4753'41 W A DISTANCE OF 154,66 FEET; THENCE, N 3735'48 W A DISTANCE OF 86.59 FEET; THENCE, N 5701'32 W A DISTANCE OF 44.89 FEET; THENCE, N 313312 W A DISTANCE OF 85.72 FEET; THENCE, N 3739'02 W A DISTANCE OF 7909 FEET; THENCE, N .373730 W A DISTANCE OF 63.32 FEET; THENCE, N 270715 W A DISTANCE OF 33.98 FEET; THENCE, N 39'52'25 W A DISTANCE OF 42.02 FEET; THENCE, N 293904 W A DISTANCE OF 107,17 FEET; THENCE, N 30'3708 W A DISTANCE OF 164.72 FEET; THENCE, N 103001 W A DISTANCE OF 107,90 FEET; THENCE, N 2756'06 E A DISTANCE OF 163.60 FEET; THENCE, N 603033 E A DISTANCE OF 177.81 FEET; THENCE, N 83'1743 E A DISTANCE OF 393.54 FEET; THENCE, N 07'1926 W A DISTANCE OF 21.79 FEET; THENCE, N 8951'11 E A DISTANCE OF 50.00 FEET; THENCE, N 801906 E A DISTANCE OF 65.56 FEET; THENCE, N 5750'04 E A DISTANCE OF 50.12 FEET; THENCE, S 8751'15 E A DISTANCE OF 33,08 FEET, THENCE, S 81'3950 E A DISTANCE OF 8961 FEET; THENCE, N 56'07'00 E A DISTANCE OF 26.86 FEET; THENCE, N 073031 E A DISTANCE OF 2793 FEET; THENCE, N 3741'57 W A DISTANCE OF 28.06 FEET; THENCE, N 50'0815 E A DISTANCE OF 22.23 FEET; THENCE, 9 82'02'30 E A DISTANCE OF 36.49 FEET; THENCE, S 6034'38 E A DISTANCE OF 54.05 FEET; THENCE, 5 45'5958 E A DISTANCE OF 20.95 FEET, THENCE, S 174120 E A DISTANCE OF 29.18 FEET; THENCE, 5 111717 W A DISTANCE OF 26.42 FEET; THENCE, 5 175041 E A DISTANCE OF 30.14 FEET; THENCE, 5 43'42'10 E A DISTANCE OF 6977 FEET, THENCE, S 31'3959 E A DISTANCE OF 56.76 FEET; THENCE, 5 493946 E A DISTANCE OF 4012 FEET, THENCE, 5 45'30'55 E A DISTANCE OF 40.88 FEET; THENCE, 5 681938 E A DISTANCE OF 43.39 FEET, THENCE, S 701924 E A DISTANCE OF 67.60 FEET; THENCE, 5 500915 E A DISTANCE OF 15.86 FEET, THENCE, S 603730 E A DISTANCE OF 52.31 FEET; THENCE, 5 83'2921 E A DISTANCE OF 46.95 FEET, THENCE, N 86'2027 E A DISTANCE OF 61.04 FEET; THENCE, N 31'5009 E A DISTANCE OF 47.07 FEET; THENCE, N 0958'38 E A DISTANCE OF 32.16 FEET; THENCE, N 7708'07 E A DISTANCE OF 798 FEET; THENCE, S 24'51'03 E A DISTANCE OF 72.35 FEET; THENCE, 5 4052'47 E A DISTANCE OF 50,71 FEET, THENCE, 5 574121 E A DISTANCE OF 38.31 FEET; THENCE, S 83'3939 E A DISTANCE OF 87,15 FEET, THENCE, S 5711'12 E A DISTANCE OF 77.06 FEET; THENCE, S 4051'16 E A DISTANCE OF 88.65 FEET, THENCE, S 5739'13 E A DISTANCE OF 65.60 FEET; THENCE, 5 4955'38 E A DISTANCE OF 7496 FEET, THENCE, 5 61'0152 E A DISTANCE OF 43.44 FEET; THENCE, 5 71'4903 E A DISTANCE OF 55.45 FEET TO THE POINT OF BEGINNING, CONTAINING. AN AREA OF 85.924 ACRES, MORE OR LESS. THE NAME AND ADORESSS 86 THE PERSON WHO CREATED MI5 LEGAL DESCRIPTION IS: JEFFREY ALLEN TUTTLE, P.L.S. 33638 727 BW(E AVENUE GLENWOOD SPRINGS, COLORADO 81601 Title: PROJECT SITE LOCATION AND DESCRIPTION (1 OF 4) Prepared by: 8140 Partners, LLC Date: 12/01/10 Exhibit: App. A-3 BITS\MISC REPORT FIGURES \PUD -L 02 PRELIM PLAT\ENGINEERING & DESIGN\CAC L20 FST\ o� Owner/Developer: \ \\ 1111 II \\\ S. ,\‘\\',.\ \ II, I \\ ' \\\ III II I I \ I v ' 1 \ \ • VI \\ II I ,�., \ \ •V AA\ AIII �/ / \ • \\\ III I // PARCEL A Vvv ,d /-4, (NORTH PARCEL) \ : \\\ II1 (( N II )/ \"\\ \\ • '\\ I VA 1 \1 \\ \\ I \\ • II \ \ \ \\ """liiillll \\ 46 \\ ` \ \ \ \ \ \\ \ \\ I 1 ,, ,,, 5\15 \ ,, ` \\ 111 1 \\ \ , \\ , ,, ,, \ 111 t� `,, \\\ I ,,,, ,, ,, .1i t , . , , ,, \\ _„„ _,,it.,..._0._,,,-_,so,_,!-,„i_-,.-_ 6 415 L136 ((Tti \ \ \\A, `. L730 \ • \</\ t2B.,,-a7Jl. v\ r ffi�� ri_ \ \ ff• iy \ .. „,,,,, \ L166 ,, '-.1r; �oa ,i^, �_ �'� Pi?RCEL C --us. ((��N.( (a V 'I 11 (SOUTHEAST -0(,6 (4. PARCEL) PARCEL B (SOUTH PARCEL) 'I 1' `CgTT� f CREEK 1 I . I 1 \ I i V Title: Date: T 200 0 200 400 SCALE IN FEET II ";_ \N- RiVerEdge COLORADO Carbondale Investments, LLC 7999 HWY 82 Carbondale, CO 81623 Phone No: 970.456.5325 PROJECT SITE LOCATION AND DESCRIPTION (2 OF 4) Prepared by: 8140 Partners, LLC 12/01/10 Exhibit: App. A-4 BITS\MISC REPORT FIGURES \PUD -L 02 PRELIM PLAT\ENGINEERING & DESIGN\CAC ‘1 I25 um -7 0 8.000., �— PARCEL 0 (SOUTHEAST PARCEL) PARCEL B (SOUTH PARCEL) ti ‹, 1 MATCHLINE V \\ tis v •\ •` \ \ � N - _.,,,,, \ • \ ., \-,,.3 + -,_ "-../83 \ v�1X HLIf • • 200 0 00 400 \\ as n SCALE IN FEET \ \ � Yea \ ATrL CREEK Owner/Developer: RhierEdge COLORADO Carbondale Investments, LLC 7999 HWY 82 Carbondale, CO 81623 Phone No: 970.456.5325 Title: PROJECT SITE LOCATION AND DESCRIPTION (3 OF 4) Prepared by: 8140 Partners, LLC Date: 12/01/10 Exhibit: App. A-5 CURVE TABLE (PROPERTY BOUNDARY) CURVE RADIUS LENGTH CHORD BEARING DELTA C1 281500 494.34 493.70 N 14'37'1" W 120742" C2 1482.50 626.05 621.41 5 21'41'2" E 24'11'44" C3 2815.00 29432 294.19 N 30'47'17" W 5'59'26" C4 2915.00 282.60 282.49 N 12'21'49" W 533'17" Owner/Developer: I _ _fie COLORADO Carbondale Investments, LLC 7999 HWY 82 Carbondale, CO 81623 Phone No: 970.456.5325 LINE TABLE (PROPERTY BOUNDARY) LINE LENGTH 8 MING LINE LENGTH BEARING Ll 1005.44 89'4330 E L85 25.14 N 6649'21° W L2 2644.53 1838'52" E L86 78.78 N 47'4750" W L3 120.78 5 9359" E L87 24.58 N 30'26'40" W L4 60.45 0536'13" W L88 30.08 N 25'47'1" W L5 64.72 49'54'10" W L89 3461 N 1911'39' W L6 86.97 49'54'10" W L90 2932 N 30'5621' W L7 5430 48'17'10" W L91 27.50 N 21'59'14" W L8 12397 56'47'27" W L92 22.97 N 30197" W L9 93.00 83'47'24" W L93 169.44 N 25'41'38° W 610 119.58 2035'31" W L94 82.61 N 41'17'39" E L11 33.84 N 78043 W L95 15.89 N 38'3652' E L12 3780 79'41'48" W 696 262.40 N 34'26'44" W 613 56.05 22'57'52" W L97 102.47 N 57599" W L14 45.48 59'31'57 W L98 10538 N 53'43'31° W L15 2823 82'32'35" W L99 126.13 N 555911' W 616 95.71 N 5073" W 6100 11842 N 5614'57° W L17 85.73 71'20'44" W L101 136.33 N 4016'4" W 618 93.22 36'43'10" W L102 150.05 6 44'30'51° W L19 181.92 25'39'22" W L103 102.14 N 32'49'55' W L20 98.43 65'10'24" W L104 552.12 N 37'44'19" W L21 52.20 S 872'33" W L105 47.26 N 18'10'2" W L22 3934 56'3352° W 6106 109.20 N 27'5899" W L23 42.96 2749'33' W L107 71.09 N 35'1'36" W L24 21.60 372743" E L108 152.23 N 41'3747" W L25 89.66 N 72'57" W L109 339.82 N 40'22'24° W L26 70.95 7024'18" W 6110 34.06 N 64'20'53' W L27 55.55 88'5939 W Lilt 52.42 N 460'36" W L28 4993 8628'58" W L112 154.66 N 44'53'41° W L29 68.20 14'22'48" E 6713 86.59 N 32'35'48" W 130 77.59 N 5'11'46" W L114 44.89 N 571'32° W L31 10.82 N 18'20'5" E 6115 85.72 N 303712' W L32 44.14 N 22'53'40" E L116 79.09 N 3739'2° W L33 35.11 N 1034'58" E L117 63.32 6 37'32'30" W L34 47.16 N 65751" E L718 33.98 N 202'15" W L35 36.48 N 3'48'8" E L119 42.02 N 3952'25" W L36 71.03 9 4'40'52" E L120 107.17 N 25'36'4" W L37 54.66 N 737'51" E L121 164.72 N 3034'8" W L38 63.68 29'28'14" W L122 107.90 N 11'39'1" W L39 61.05 N 32'644" W 6123 163.60 N 26556" E L40 55.52 20729" W L124 177.81 N 63'39'33" E L41 44.36 38814'36" W L125 393.54 N 83'14'43" E L42 37.73 5011'32" W L126 21.79 N 7'15'26" W L43 54.16 59'54'48" W L127 50.00 N 80'51'11" E L44 36.97 8751'35" W 6128 65.56 N 8015'6" E L45 65.70 57'33'47" W L129 50.12 9 57'50'4" E L46 85.02 81'56'22" W L130 33.08 5 84'51'15" E L47 158.65 N 4'11'29" W L131 89.61 S 81'39'50" E L48 41 30 35'5041" W L132 26.86 N 5070° E L49 2470 N 54'46'3" W L133 27.93 N 738'31" E 650 209.99 28'51'45" W L134 28.06 N 37'41'57" W L51 33.82 11'58'37" W L135 22.23 N 50'0'15" E L52 78.19 N 41'3'46" E 6736 36.49 N 82'2'30" E L53 117.20 N 629'1" W 6137 54.05 S 653438° E L54 94.24 9 205'27 W L138 20.95 5 45'59'58° E L55 63.83 N 11'32'3" W L139 2918 S 14'44'20" E L56 141.45 N 7'57'45" W L140 26.42 9 11'11'17° W L57 50.76 N 756'14" E L141 30.14 S 14'5941" E L58 91.04 N 19'17'44" W L142 69.77 5 43'42'10° E L59 134.55 N 44'41'59" W L143 56.76 5 31'36'59" E 160 74.18 N 19'23'49" W L144 40.12 5 49'38'46° E L61 43.27 N 1933'6" W L145 40.88 5 45'30'55" E 662 72.23 N 21'30'1" W L146 43.39 5 60'16'38" E L63 217.77 N 016'30" E L147 67.60 S 73'16'24" E L64 31294 N 0'16'30 E L148 15.86 5 53'5'15" E L65 401.79 S 9'35'9" E L149 5231 S 63'37'30" E L66 1545.87 9 9'35'9" E LI 50 46.95 5 83'28'21° E L67 387.28 304654" E L151 61.04 9 8620'27" E L68 218.07 89'53'16" W L152 47.07 N 31'59'9° E L69 69.38 40'23'30" W L153 32.16 N 65.638° E L70 36.35 87'28'29 W L154 798 N 72'8'7° E L71 10.80 8052'72" W 6155 72.35 S 24'51'3° E L72 41.45 562719" W L156 50.71 5 41'52'47" E L73 8.28 29'51'31" W 6157 38.31 S 5644'21" E L74 25.22 24'16'24" W 6158 87.15 5 83'39'39" E L75 9.87 N 69'053" W L159 77.06 5 5711'12" E L76 22.60 8731'44" W LI60 88.65 5 475716° E L77 17.28 N 5725'1" W 6161 65.60 5 5739'13" E L78 26.07 N 50'9'49" W 1162 7496 5 49'55'38" E L79 999 N 4621'12" W 6163 4344 S 61'4'52" E L80 21.45 N 44'285 W L164 55.45 5 77492" E L81 49.05 N 55'50'8" W L165 188.14 N 935'117 W L82 4994 N 56'25'40" W 6166 49.74 E L83 36.45 N 68'12'23" W L167 202.70 5 6'1'0" E L84 55.18 N 46'54'4" W 6168 260.70 5 4'34'58" E Title: PROJECT SITE LOCATION AND DESCRIPTION (4 OF 4) Prepared by: 8140 Partners, LLC Date: 12/01/10 Exhibit: App. A-6 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX B: RAINFALL INPUT App. B-1 IDF TABLE FOR ZONE TWO IN THE STATE OF COLORADO Zone 2: San Juan, Upper Rio Grande, Upper Colorado, and Gunnison River Basins, and Green River Basin below Confluence with the Yampa River Project: River Edge Colorado IDF Calculation Enter the elevation at the center of the watershed: Elev = 6,020 (input) 1. Rainfall Depth -Duration -Frequency Table Enter the 6 -hour and 24-hour rainfall depths from the NOAA Atlas 2 Volume III in rightmost blue columns Return Period Rainfall Depth in Inches at Time Duration 5 -min 10 -min 15 -min 30 -min 1 -hr 2 -hr 3 -hr 6 -hr 24 -hr (1) (2) (3) (4) (5) (6) (7) (8) (9) (1 0) output output output output output output output input input 2 -yr 0.18 0.27 0.35 0.48 0.61 0.70 0.76 0.88 1.18 5 -yr 0.25 0.39 0.50 0.69 0.87 0.98 1.05 1.18 1.50 10 -yr 0.30 0.47 0.60 0.83 1.05 1.15 1.22 1.35 1.75 25 -yr 0.37 0.57 0.72 1.00 1.27 1.38 1.46 1.60 2.10 50 -yr 0.43 0.66 0.84 1.17 1.48 1.59 1.66 1.80 2.35 100 -yr 0.49 0.75 0.95 1.32 1.67 1.78 1.86 2.00 2.56 Note: Refer to NOAA Atlas 2 Volume III isopluvial maps for 6 -hr and 24 -hr rainfall depths. 2. Rainfall Intensity -Duration -Frequency Table Return Period Rainfall Intensity in Inches Per Hour at Time Duration 5 -min 10 -min 15 -min 30 -min 1 -hr 2 -hr 3 -hr 6 -hr 24 -hr (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) output output output output output output output output output 2 -yr 2.11 1.64 1.38 0.96 0.61 0.35 0.25 0.15 0.05 5 -yr 3.04 2.36 1.99 1.38 0.87 0.49 0.35 0.20 0.06 10 -yr 3.65 2.83 2.39 1.66 1.05 0.58 0.41 0.23 0.07 25 -yr 4.42 3.43 2.90 2.01 1.27 0.69 0.49 0.27 0.09 50 -yr 5.14 3.99 3.37 2.33 1 1.48 0.79 0.55 0.30 1 0.10 100 -yr 5.82 4.52 3.82 2.64 1.67 0.89 0.62 0.33 0.11 River Edge Colorado IDF Calculations 12/26/2010 1 of 2 Zone 2 App. B-2 1.80 1.60 1.40 1.20 N 1.00 -c 0 = 0.80 cts 0.60 0.40 0.20 0.00 River Edge Colorado IDF Calculations 12/26/2010 One -Hour Rainfall Depth Design Chart 1.48 • 1.27 40 1.67 • 1.05 0.87 • 061 • 2 -yr 5 -yr 10 -yr 25 -yr 50 -yr 100 -yr Return Period 2 of 2 Zone 2 App. B-3 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX C: IDF CURVE DATA App. C-1 INTENSITY (in/hr) 6.00 5.00 Figure INTENSITY -DURATION -FREQUENCY CURVES RIVER EDGE COLORADO Derived using NOAA Maps and Methodology —r —a' ........... � MMMMMMMMM • NIZTMEMMM War 0.00 0 20 40 60 DURATION (min) 80 100 — 2 -Year 5 -Year 10 -Year 25 -Year 50 -Year — 100 -Year 120 App. C-2 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX D: BASIN DELINEATION MAP App. D-1 TANDARD.CTB BASIN OS -1 i.1--\---— � �\ ;—�-- j �lJ= \��\ BASIN P2 7 200 0 200 400 SCALE IN FEET Tr- .r I- - -7-1-7 -1-1 I_LJ—LJ_LJ_L1— \ , r--\-- - i /C-71-1771—F77-77-1,7-17-7--- _ AJOR CONVEYANCE "� Y �� CHANNEL (TYP.) //'\ `, \ \_---I. ' ,, \\,,, •••. - ' 7 // �/<� /�—� / BASIN P3 yL I 1 L U L\�\ BASIN P1 WATER QUALITY POND (NP1) (')( Rpm\\ R/k •• •- /• WATER QUALITY POND (NP2),j y \I i �, vi' / ' /5 ..'v' /) -- y' /< --1 , , , `�, 1 li-L- >'� __ ---�- / /----� —\ '\,,y, `'y/ ,� ''u /'''</ /N '> /N '‘\/''v / / /N. 0/ �1 y/ v / WATER QUALITY POND (SP1) Owner/Developer: Rft-rEdge COLORADO Carbondale Investments, LLC 7999 HWY 82 Phone No: Carbondale, CO 81623 970.456.5325 / 7 Title: Basin Boundary Map Prepared by: 8140 Partners, LLC Date: 01/14/2011 Figure: 1 App. D-2 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX E: PRE- AND POST -DEVELOPMENT WATER STORAGE AND QUALITY DATA App. E-1 N C a)r,� in n in 000 (-Ni ,, Ln d- co Ql O N 0' d 0 0 00 O Q N Ql al O N N M l0 Z Lo lD M m ,__1- rn (-Ni N o0 eft 0 coo ▪ m rn in o m o N O Ni Lll 01 d D> O> r41 Cl. oo0 0 ,n O M LD L!1 O p� d'' l0 a M • lc)is) N ,—iM N. co l0 N .-1 en M.0 o O O N O Q M N d- OO a a;CO cn L11 ch . ,r crc • Lc'�-I Z o0 ,-I - N N N N • ' c -I co 113v Garden Homes O a- • 4-, t b.0 O .> v E App. E-2 Impervious 2 -YR 5 -YR 10 -YR 25 -YR 50 -YR 100 -YR 0% 0 0 0.05 0.12 0.16 0.2 5% 0 0.02 0.1 0.16 0.2 0.24 10% 0 0.06 0.14 0.2 0.24 0.28 15% 0.02 0.1 0.17 0.23 0.27 0.3 20% 0.06 0.13 0.2 0.26 0.3 0.33 25% 0.09 0.16 0.23 0.29 0.32 0.35 30% 0.13 0.19 0.25 0.31 0.34 0.37 35% 0.16 0.22 0.28 0.33 0.36 0.39 40% 0.19 0.25 0.3 0.35 0.38 0.41 45% 0.22 0.27 0.33 0.37 0.4 0.43 50% 0.25 0.3 0.35 0.4 0.42 0.45 55% 0.29 0.33 0.38 0.42 0.45 0.47 60% 0.33 0.37 0.41 0.45 0.47 0.5 65% 0.37 0.41 0.45 0.49 0.51 0.53 70% 0.42 0.45 0.49 0.53 0.54 0.56 75% 0.47 0.5 0.54 0.57 0.59 0.61 80% 0.54 0.56 0.6 0.63 0.64 0.66 85% 0.61 0.63 0.66 0.69 0.7 0.72 90% 0.69 0.71 0.73 0.76 0.77 0.79 95% 0.78 0.8 0.82 0.84 0.85 0.86 100% 0.89 0.9 0.92 0.94 0.95 0.96 From UDFCD Criteria Manual Vol. 1, Table RO-5 River Edge Colorado Runoff Coefficients 12/26/2010 UDFCD Criteria Marl. E-3 as d m O a) a >' O .c a CC X x CC cc r° a CD °)0 0 O > U Q 0 N 0 0 N 0 0 N 0 0 N 0 a) 0 O �n > U Q (0 0 (0 0 (0 0 (0 0 a) 0LO I > 0 Q CV ,- 0 r r 0 CV N 0 CV 0 a) N o t- y- > 0 Q 0 O 0 i0 O 0 0 O 0 LO O 0 a) 0 a)U Q 0 0000 0 0 0 0 0 0 0 a) O O N 0 U Q O O 0 O O 0 O O 0 O O 0 Surface Type 1 0 N Q 428,079 1 (0 vi in d) 2,652,955 1,028,020 O O E3 0 N 0000 0 N 0 N 0 N O U (0 0 (0 0 (0 0 (0 0 1.0 N U a-rr 0 0 0 r 0 0 0 (0 0 0 LO 0 0 LO 0 0 (0 0 0 U 0000 0 O 0 O 0 O 0 O N U 0 0000 0 0 0 0 0 0 0 Total Area Total Area acres sq mi 0.0154 0 h O O 0.0952 0) (0 M O O 9.83 OD ao v O rn 0 (0 O (o C) N Total Area sf 428,079 1,955,161 so (0 0) N so (0 N 1,028,020 Basin 000 1 OS-FUT-1 M O CO - a) ❑ d 0 U 3 as a) > LL C O) O 1:3E .O lgc, -.Y N N 0 O II M >.oN3> oJ�°„ = oNI.m HII �II J 2= n)Uma0a ) ea 0 • rn; o asc 0 0 U cn = O 0 E 112 o c 26- a. nC L 7 C''5(1)Q) 13 0_ O) .„ N ❑ M M L 'E O N 0_) 0 (6 O • H f� f. co -0 c >> a) m O o 0 3 o o) m CD 0 0 T a `m U U U N 0 0.. O N> O LE) ri6)UZU' a ea N 0 ❑ 10 N (000N r.-- 0)000 Y O .>, 0 0 0 0 N 0 0 • 0 0 (0 )CD L6 ❑ ❑ o N > 00 Z U N M Rational Method M O App. E-4 E 0 o U E E � O E E E o as 3`0 o -a c '0 @ c 3 o a)� > o o LO 176 o 0 o O 0 U O C.) Co CO O N 0N 0 E @ z E D co E E @ E @ E .c co co N @ ED @ Cp L N N 7 @ .. c O 2 2 N 0 -00 O o O U Eo_ �) o 0) - -o w ay > CD a Also in urban area the tc shall not exceed the total length/180+10 min. Channel Tc3 Total Tc min min N CO CO CN CO CO N- CO CO CO d CO •:I- CO O) CO 14.10 59.24 47.21 65.00 Initial Tc2 min CO CO r- r COr co CO r- CY) co >. U NCn O - a) > > m r m o M 0 ,- 0.50 1 Land Cover Factor (k) 0 0) o 0 0) o 0 0) 0 0 rn 0 Average Slope M N 0 O 0.005 0.013 0.003 Low Point Elevation co O 0 � rn Lo0 6004.00 5989.50 6026.00 High Point Elevation 6013.00 0 0 0 0 6028.00 6032.00 Channel flow Length ft 0 O CO 1 2307.00 1 2925.00 1 1948.00 Average Slope 0.010 o O O 0.012 M O O Low Point Elevation co O M O CO O O CO O CO 6028.00 6032.00 High Point Elevation 0 O O O CO 6018.00 6031.50 6034.00 Initial Length ft o O o o co 300.00 I 300.00 o o o Lo r Total Area Total Area acres sq mi COO r O o O O 0.0952 0.0369 co � o 44.88 O rn m 23.60 Total Area sf 428,079 1,955,161 rn N L. O N 1,028,020 Basin r aaau- N M H D ch0 Rational Method CO O N N 0 U U 0 c o • A- o • E U a O N W N N > ) co E ar App. E-5 O a) 0 rn E co 0 T Q O O O r (0 > O oZ To U N U) 0 =a '00 @U O a) O U Eo_ a) o (r- W > �, CD > a`) a o o u) 6.40 0 co 22.14 i100 in/hr Lt) N M (O0 r N r N L. r i50 Q50 in/hr cfs 4.08 o) CO M • • N CO 4 O CO N d N r LO d' r N N r Q25 cfs 2.71 5.90 CO of 3.06 Lo-cM N .0 N O co r co r Q10 cfs 0.97 1 — ‘- N (O () C) O i10 in/hr (o4oco O) O) O r r O) O i5 Q5 in/hr cfs 0.00 0.00 0.00 0.00 CO CO O) IL- o CO O o CO r 0 i2 Q2 in/hr cfs 0 0 0 0.00 0.00 0.00 r N r co (O O co CO O 1 0.57 Total Area Total Area acres sq mi CO r O O co 0 O O 0.0952 0.0369 co � ai 44.88 0 co m 23.60 Total Area sf 428,079 1,955,161 Lo rn N (n (O N 1,028,020 Basin r aaau- N M H D (n 0 Rational Method App. E-6 a) N O a) O_ w0 O 0 0) Z .c a c m X x c `° a) ma a) > 0 Q 0 0 0 0 0 0 0 0 Average Average C25 C50 M O CO O M O CV O CV O CV O CV O CV O a) N O 10 M O M O 00000 V' O V' O V' O V' O V' O a) (Oa O > U Q M 0 OM 0 N 0 M 0 M 0 M 0 M 0 M 0 a) CD > V Q aJ 0 100)00000 0 0 0 0 0 0 0 a) O) @ N 0 Q O 0 0 0 r 0 M r 0 to N 0 to N 0 NN 0 LO 0 LO N 0 Surface Type 1 C100 Area 428,079 1 (0a0 LCi 1nd) 0 2,652,955 1,028,020 337,038 a) CCD M W M 0) M 0 V' 0 I� M 0 0) V' 0 10 V' 0 10 V' 0 0) V' 0 0) V' 0 C5 C10 C25 C50 N00 0 0 Ni- 0 N 0 N 0 N 0 NN 0 0 0) N 0 10 M 0 M 0 00000 V' 0 V' 0 V' 0 V' 0 V' 0 M N 00000000 C./ (n N LO M LO M LO M 0) M 00 M m O 1O N O 0) O 0 M O 0 co O 0 co O O co O O co O N N 0) O 00000000 0) co 10 N 10 N 10 N 10 N 10 N Total Area sq mi 0.0154 O(O N- O O 0.0952 0) co O O 0.012 0.004 r'- O O O 0.012 Total Area acres co a0 0) 44.88 O m g 23.60 7.74 N N 4.30 7.48 Total Area sf 428,079 1,955,161 0, (no 0). csi (0 N 1,028,020 337,038 co 0) 187,306 325,754 Basin 000 1 OS-FUT-1 m > z 1 N -SUB -2 m > ch 1 S -SUB -2 0) d O c O V' N c) 0) a) N .0 `) O (a 13 > o 713 a• 0. 0 0 u) W a) a) 0) 0) > > Q Q o .— o c _ N ,_5 -. LL E O m O 0 ._ Y N N a3 O II M• > 0 J 13 42 '5 = m C a) ("NI! J II II Ca a = 3 N U )0 'O �° 0 C O a) 7 a) C '',2 O Tao' O a)8 O = • LL O) O)7 L 0 N2 0) O -2-- -9-- , E m' a' a L 'O 0 M M a) a3 m (n C d 0 N 0 M 0') L 'E a) N a) a) a3 N -0 O d O m 00 0 0 3 0 `2 0 -O a) a) 0 0 0 in- 3 '0 T to -0 U U a) 0 0 7- a) > CD O g� () i(m(ci)ig 0Z0a. )n 00 10000000 0; 0 0 . N 10 I- 0) O 10 0 U, .0 H H 0 0 0 0 N vi0 000 CD 0 I-6 > 0 0 Z 0 N CO V Rational Method M O (0 0 O U a) 0 O o cc m � O 0) U - m a CO -0 > W O N > ox- y M CLa App. E-7 c E O O E U E E Ln z E E E C_ @ 3 L ° o .1 c • CO C CO o a>� > o ecs N O ▪ O O 0 U c M O N a) 'p 0 E @ 7 E 'o m E E @ X @ E L @ co N @ a) (a co L N N cc co 7 � .. • ca O 2 Z Also in urban area the tc shall not exceed the total length/180+10 min. Initial Tc2 Channel Tc3 Total Tc min min min O O 24.48 1 N 0 N O 0 N O 0 O 0 O 0 O 0 V co• LO ) M N N N M V O CO CO O ,- O) LO (NI LO M T UO fl. > N N co 7 N 7 7 7 Land Cover Factor (k) 1.50 1.50 1.50 2.00 Average Slope M N O O 0.005 0.013 0.003 Low Point Elevation 0 (O 0 0 Lo 6004.00 LO O) 0 rn co 6026.00 0.00 0.00 0.00 0.00 High Point Elevation 6013.00 0 O OD ( o N O ( D 6032.00 O 0 O O 0 O O 0 O O 0 O Channel flow Length ft 0 O O 2307.00 2925.00 1948.00 O 0 O O 0 O O 0 O O 0 O Average Slope O O O O O O 0.012 0.013 0.020 0.020 0.020 0.020 Low Point Elevation 6013.00 6016.00 6028.00 6032.00 High Point Elevation O O O O CO O O a0 O CO 6031.50 6034.00 Initial Length ft 0 0 0 0 M 300.00 300.00 1 150.00 Total Area sq mi 0.0154 0 r• -•O 0 O 0.0952 0.0369 N_ 0 0 0.004 N. O O N 0 O Total Area acres a0 0 44.88 o> CO O N 7.74 N N M d- 7.48 Total Area sf 428,079 1,955,161 LO Lo rn N OO co N 1,028,020 337,038 w m O O 187,306 co N co Basin aaa N M 1 OS-FUT-1 m > Z 1 N -SUB -2 m > (n 1 S -SUB -2 Rational Method M O N u) C O c3 U U O o "a' 0 U p) > r 'O 0 TZ> w 0 N y °O m� App. E-8 O 0) 0 E f6 T .0 O° (0 > O ciZ CO CiN 0 c O 0 -O 0 0)) o E U a O 0) 0) o > Lo N 2a o _ U C5 13.23 (q CC) 10 63.05 34.56 I IS oi 6 0 0/ co 111 O) 0 -C 7 .0 3.85 Cr) M 2.80 N C` -i COO O COO O COO O COO CO Q50 cfs 0 6 N. a N a CI is: N Cl" M a r OD 14.20 1 i50 in/hr Is O C+) V N r) N N 0 CO N N LI) 4 N CO 4 N O V Cl O i25 Q25 in/hr cfs N.O N: M 37.38 1 r`:C (7, 12.38 1 CNO ri W (o Of N i4".• N BOO N O) 2.30 4.00 4.00 OO O d' O V i10 Q10 in/hr cfs 5.29 24.78 000 lei N M ,, gin O) 00) f- CO et •Co (4 t- t- co M CO Ch i5 Q5 in/hr cfs 3.08 17.30 46r(o.=ri 5.40 1 co Cn In CO V r CO CO r O) (O N O) (O N O) O N O) W N i2 Q2 in/hr cfs 1.27 1 CN O) O) N 00 111 I- O a 0)N — N OO r) CO V M 7. 4 O r N t- N _ N _ N _ N Total Area sq mi 0.0154 0 N. 0 O 0.0952 0.0369 0.012 0.004 I� 0 O O 0.012 Total Area acres co O) 44.88 m g O N 7.74 N N M 4 7.48 Total Area sf 428,079 1,955,161 N OO O (Ni 1,028,020 337,038 COto m co O 187,306 N M Basin N - aaa CO 1 OS-FUT-1 co m > Z 1 N -SUB -2 m (n 1 S -SUB -2 Rational Method O M V1 0 O 0 U CO o n, m � 0 0) 0 - CD 0) N ‘- co 0 N > y M App. E-9 Existing C 1 A Q in/hr acres cfs 3.25 9.8 Proposed input C 1 A Q constant calculated from other cell in/hr acres cfs 0.35 3.85 • C values from typical tables for Rational Method coefficients I values from NOAA River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 1 of 5 Rat Method NP1 App. E-10 Based on FAA method in Handbook of Hydrology, p. 28.27 Qout = Qin = Qout/Qin = k= Runoff coeff Impervious 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 Mir Area A acres 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8 6.39 13.25 0.48 1.50 storm Rainfall duration intensity T min in/hr 5 5.39 6 5.15 7 4.91 8 4.67 9 4.43 10 4.19 11 4.06 12 3.93 13 3.79 14 3.66 15 3.53 16 3.46 17 3.39 18 3.31 19 3.24 20 3.17 21 3.10 22 3.03 23 2.95 24 2.88 25 2.81 26 2.74 27 2.67 cfs (historic) Impervious Ratio cfs (developed) Drain Time (hr) WQCV (in) (from graph) storage factor (sf) Volume Volume CIAT k(Qout)T cu ft cu ft Volume WQ Volume runoff minus outflow (WQCV/12)*A*sf 0.25 40 0.135 1 Total From UDFCD Manual Vol. 3 Figure EDB -2 input 1 constant cu ft cu ft cu ft 1 calculated 14,906 2,875 17,090 19,010 20,663 22,051 12,030 4,817 3,450 13,640 4,025 14,984 4,600 16,063 5,175 16,876 16,848 1 from other cell 4,817 18,457 4,817 19,801 4,817 20,880 4,817 21,693 23,174 5,751 17,424 4,817 22,241 24,689 6,326 18,363 4,817 23,180 26,057 6,901 19,156 4,817 23,9 27,279 7,476 19,804 4,817 24,621 28,356 8,051 20,305 4,817 25,122 29,286 8,626 20,660 4,817 401 30,601 9,201 21,400 4,817 31,837 9,776 22,061 4,817 26,878 32,993 10,351 22,642 4,817 27,459 34,069 10,926 23,143 4,817 27,960 35,066 11,501 23,564 4,817 28,382 35,983 12,076 23,906 4,817 28,724 36,820 12,651 24,169 4,817 28 986 37,578 13,226 24,351 4,817 38,256 13,801 24,454 4,817 29,272 38,854 14,376 24,478 4,817 29,295 39,373 14,951 24,422 4,817 39,812 15,526 24,286 4,817 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 2 of 5 FAA detentn NP1 App. E-11 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 28 2.59 29 2.52 30 2.45 31 2.42 32 2.39 33 2.36 34 2.33 35 2.30 36 2.27 37 2.24 38 2.21 39 2.18 40 2.15 41 2.12 42 2.09 43 2.06 44 2.03 45 2.00 46 1.97 47 1.94 48 1.91 49 1.88 50 1.85 51 1.82 52 1.79 53 1.76 54 1.73 55 1.70 56 1.67 57 1.64 58 1.61 40,172 16,102 24,070 4,817 28,887 40,452 16,677 23,775 4,817 28,592 40,652 17,252 23,400 4,817 28,217 41,492 17,827 23,666 4,817 28,483 42,300 18,402 23,898 4,817 28,715 43,074 18,977 24,097 4,817 28,91 11 43,815 19,552 24,264 4,817 29,081 44,523 20,127 24,396 4,817 29,214 45,198 20,702 24,496 4,817 1011 45,840 21,277 24,563 4,817 46,448 21,852 24,596 4,817 29,413 47,023 22,427 24,596 4,817 29,413 47,565 23,002 24,563 4,817 29,380 48,074 23,577 24,497 4,817 29,314 48,550 24,152 24,397 4,817 29,215 48,992 24,727 24,265 4,817 29 0 2 49,402 25,302 24,099 4,817 49,778 25,877 23,900 4,817 28,717 50,121 26,453 23,668 4,817 28,485 50,430 27,028 23,403 4,817 50,707 27,603 23,104 4,817 4011 50,950 28,178 22,772 4,817 27,590 51,160 28,753 22,408 4,817 27,225 51,337 29,328 22,010 4,817 26,827 51,481 29,903 21,578 4,817 26,395 51,592 30,478 21,114 4,817 25,931 51,669 31,053 20,616 4,817 25,433 51,713 31,628 20,085 4,817 24,903 51,725 32,203 19,521 4,817 24,339 51,702 32,778 18,924 4,817 23,741 51,647 33,353 18,294 4,817 23,111 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 3 of 5 FAA detentn NP1 App. E-12 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 59 1.58 60 1.55 61 1.54 62 1.53 63 1.52 64 1.51 65 1.49 66 1.48 67 1.47 68 1.46 69 1.45 70 1.44 71 1.43 72 1.42 73 1.40 74 1.39 75 1.38 76 1.37 77 1.36 78 1.35 79 1.34 80 1.33 81 1.32 82 1.30 83 1.29 84 1.28 85 1.27 86 1.26 87 1.25 88 1.24 89 1.23 51,559 33,928 17,630 4,817 22,448 51,437 34,503 16,934 4,817 21,74 51,917 35,078 16,839 4,817 21,656 52,386 35,653 16,732 4,817 21,549 52,841 36,228 16,613 4,817 21,430 53,285 36,804 16,481 4,817 21,299 53,716 37,379 16,337 4,817 21,155 54,135 37,954 16,181 4,817 20,998 54,541 38,529 16,013 4,817 41,1111 54,935 39,104 15,832 4,817 55,317 39,679 15,638 4,817 20,455 55,686 40,254 15,433 4,817 20,250 56,043 40,829 15,215 4,817 20,032 56,388 41,404 14,984 4,817 19,801 56,720 41,979 14,741 4,817 19,559 57,040 42,554 14,486 4,817 19 304 57,348 43,129 14,219 4,817 57,643 43,704 13,939 4,817 18,756 57,926 44,279 13,647 4,817 18,464 58,197 44,854 13,342 4,817 18,160 58,455 45,429 13,026 4,817 17,843 58,701 46,004 12,696 4,817 17,514 58,934 46,579 12,355 4,817 17,172 59,155 47,155 12,001 4,817 16,818 59,364 47,730 11,635 4,817 16,452 59,561 48,305 11,256 4,817 16,073 59,745 48,880 10,865 4,817 1 682 59,916 49,455 10,462 4,817 60,076 50,030 10,046 4,817 14,863 60,223 50,605 9,618 4,817 14,435 60,358 51,180 9,178 4,817 13,995 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 4 of 5 FAA detentn NP1 App. E-13 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 90 1.22 91 1.20 92 1.19 93 1.18 94 1.17 95 1.16 96 1.15 97 1.14 98 1.13 99 1.11 100 1.10 101 1.09 102 1.08 103 1.07 104 1.06 105 1.05 106 1.04 107 1.03 108 1.01 109 1.00 110 0.99 111 0.98 112 0.97 113 0.96 114 0.95 115 0.94 116 0.92 117 0.91 118 0.90 119 0.89 120 0.88 60,480 51,755 8,725 4,817 13,542 60,590 52,330 8,260 4,817 13,077 60,687 52,905 7,782 4,817 12,600 60,773 53,480 7,293 4,817 12,110 60,846 54,055 6,790 4,817 11,608 60,906 54,630 6,276 4,817 11,093 60,954 55,205 5,749 4,817 10,566 60,990 55,780 5,210 4,817 10,027 61,014 56,355 4,658 4,817 011 61,025 56,930 4,094 4,817 61,024 57,506 3,518 4,817 8,335 61,010 58,081 2,930 4,817 7,747 60,984 58,656 2,329 4,817 7,146 60,946 59,231 1,715 4,817 6,533 60,895 59,806 1,090 4,817 5,907 60,832 60,381 452 4,817 5269 60,757 60,956 -199 4,817 60,669 61,531 -861 4,817 3,956 60,569 62,106 -1,537 4,817 3,281 60,457 62,681 -2,224 4,817 2,593 60,332 63,256 -2,924 4,817 1,893 60,195 63,831 -3,636 4,817 1,181 60,046 64,406 -4,360 4,817 45 59,884 64,981 -5,097 4,817 28�^ 59,710 65,556 -5,846 4,817 -1,029 59,523 66,131 -6,608 4,817 -1,791 59,325 66,706 -7,382 4,817 -2565 59,113 67,281 -8,168 4,817 58,890 67,856 -8,967 4,817 -4,149 58,654 68,432 -9,778 4,817 -4,960 58,406 69,007 -10,601 4,817 -5,784 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 5 of 5 FAA detentn NP1 App. E-14 Existing C 1 A Q in/hr acres cfs 1.54 44.9 Proposed input C 1 A Q constant calculated from other cell in/hr acres cfs 0.41 3.03 typical tables for Rational C values from Method coefficients I values from NOAA River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 1 of 5 Rat Method NP2 App. E-15 Based on FAA method in Handbook of Hydrology, p. 28.27 Qout = Qin = Qout/Qin = k= Runoff coeff Impervious 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0,93 90 0.93 90 IMF Area A acres 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 13.82 55.75 0.25 1.50 storm Rainfall duration intensity T min in/hr 5 5.39 6 5.15 7 4.91 8 4.67 9 4.43 10 4.19 11 4.06 12 3.93 13 3.79 14 3.66 15 3.53 16 3.46 17 3.39 18 3.31 19 3.24 20 3.17 21 3.10 22 3.03 23 2.95 24 2.88 25 2.81 26 2.74 27 2.67 cfs (historic) Impervious Ratio cfs (developed) Drain Time (hr) WQCV (in) (from graph) storage factor (sf) WQ Volume Volume Volume Volume runoff minus CIAT k(Qout)T outflow (WQCV/12)*A*sf 0.39 40 0.177 Total From UDFCD Manual Vol. 3 Figure EDB -2 input 1 constant cu n cu ft cu n cu n cu ft 1 calculated 68,053 6,220 61,833 28,836 90,669 78,028 7,464 70,563 28,836 99,399 86,790 8,709 78,082 28,836 106,918 94,340 9,953 84,388 28,836 113,2 100,679 11,197 89,482 28,836 118,318 105,805 12,441 93,364 28,836 122,200 112,719 13,685 99,034 28,836 127,870 118,966 14,929 104,037 28,836 132, 11 124,547 16,173 108,374 28,836 137,209 129,461 17,417 112,044 28,836 140,879 133,708 18,661 115,047 28,836 1., ell 139,713 19,905 119,808 28,836 1' 145,354 21,149 124,205 28,836 153,041 150,632 22,393 128,238 28,836 157,074 155,546 23,637 131,908 28,836 160,744 160,096 24,881 135,215 28,836 164,050 164,283 26,126 138,157 28,836 166,993 168,106 27,370 140,736 28,836 169 572 171,565 28,614 142,952 28,836 174,661 29,858 144,803 28,836 173,639 177,393 31,102 146,292 28,836 175,127 179,762 32,346 147,416 28,836 176,2. 81,767 33,590 148,177 28,836 177,. from other cell River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 2 of 5 FAA detentn NP2 App. E-16 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 28 2.59 29 2.52 30 2.45 31 2.42 32 2.39 33 2.36 34 2.33 35 2.30 36 2.27 37 2.24 38 2.21 39 2.18 40 2.15 41 2.12 42 2.09 43 2.06 44 2.03 45 2.00 46 1.97 47 1.94 48 1.91 49 1.88 50 1.85 51 1.82 52 1.79 53 1.76 54 1.73 55 1.70 56 1.67 57 1.64 58 1.61 183,408 34,834 148,574 28,836 177,410 184,686 36,078 148,608 28,836 177,444 185,600 37,322 148,278 28,836 177,114 189,438 38,566 150,872 28,836 179,708 193,125 39,810 153,315 28,836 18 151 196,660 41,054 155,606 28,836 200,044 42,299 157,746 28,836 186,582 203,276 43,543 159,734 28,836 188,570 206,357 44,787 161,571 28,836 1 „ EA 209,286 46,031 163,256 28,836 1.•, 11 212,064 47,275 164,789 28,836 193,625 214,690 48,519 166,171 28,836 195,007 217,165 49,763 167,402 28,836 196,238 219,488 51,007 168,481 28,836 197,317 221,660 52,251 169,409 28,836 198,244 223,680 53,495 170,185 28,836 199 021. 225,548 54,739 170,809 28,836 1 , 227,266 55,983 171,282 28,836 200,118 228,831 57,227 171,604 28,836 200,440 230,245 58,471 171,774 28,836 200,610 231,508 59,716 171,792 28,836 200,628 232,619 60,960 171,659 28,836 200,495 233,579 62,204 171,375 28,836 200,211 234,387 63,448 170,939 28,836 199,775 235,043 64,692 170,351 28,836 199,187 235,548 65,936 169,612 28,836 198,448 235,902 67,180 168,722 28,836 197,558. 236,104 68,424 167,680 28,836 196,51 1111 236,154 69,668 166,486 28,836 195,322 236,053 70,912 165,141 28,836 193,977 235,801 72,156 163,644 28,836 192,480 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 3 of 5 FAA detentn NP2 App. E-17 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 59 1.58 60 1.55 61 1.54 62 1.53 63 1.52 64 1.51 65 1.49 66 1.48 67 1.47 68 1.46 69 1.45 70 1.44 71 1.43 72 1.42 73 1.40 74 1.39 75 1.38 76 1.37 77 1.36 78 1.35 79 1.34 80 1.33 81 1.32 82 1.30 83 1.29 84 1.28 85 1.27 86 1.26 87 1.25 88 1.24 89 1.23 235,397 73,400 161,996 28,836 190,832 234,841 74,644 160,197 28,836 189,033 237,035 75,888 161,147 28,836 189,982 239,173 77,133 162,040 28,836 190,876 241,254 78,377 162,877 28,836 191,7 243,279 79,621 163,658 28,836 192,4 245,247 80,865 164,382 28,836 193,218 247,159 82,109 165,050 28,836 193,886 249,014 83,353 165,662 28,836 1 li 250,814 84,597 166,217 28,836 1 252,556 85,841 166,715 28,836 195,551 254,243 87,085 167,158 28,836 195,994 255,873 88,329 167,544 28,836 196,379 257,446 89,573 167,873 28,836 196,709 258,964 90,817 168,146 28,836 196,982 260,424 92,061 168,363 28,836 _Alai 261,829 93,306 168,523 28,836 71.11! 263,177 94,550 168,627 28,836 197,463 264,469 95,794 168,675 28,836 197,511 265,704 97,038 168,666 28,836 1 il 266,883 98,282 168,601 28,836 1 3 gi 268,005 99,526 168,479 28,836 197,315 269,071 100,770 168,301 28,836 197,137 270,081 102,014 168,067 28,836 196,903 271,034 103,258 167,776 28,836 196,612 271,931 104,502 167,429 28,836 196,265 272,771 105,746 167,025 28,836 195,861 273,555 106,990 166,565 28,836 195,401 274,283 108,234 166,049 28,836 194,884 274,954 109,478 165,476 28,836 194,312 275,569 110,723 164,847 28,836 193,683 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 4 of 5 FAA detentn NP2 App. E-18 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 44.9 90 1.22 91 1.20 92 1.19 93 1.18 94 1.17 95 1.16 96 1.15 97 1.14 98 1.13 99 1.11 100 1.10 101 1.09 102 1.08 103 1.07 104 1.06 105 1.05 106 1.04 107 1.03 108 1.01 109 1.00 110 0.99 111 0.98 112 0.97 113 0.96 114 0.95 115 0.94 116 0.92 117 0.91 118 0.90 119 0.89 120 0.88 276,128 111,967 164,161 28,836 192,997 276,630 113,211 163,419 28,836 192,255 277,075 114,455 162,621 28,836 191,457 277,465 115,699 161,766 28,836 190,602 277,798 116,943 160,855 28,836 189,691 278,074 118,187 159,887 28,836 188,723 278,294 119,431 158,863 28,836 187,699 278,458 120,675 157,783 28,836 186,619 278,565 121,919 156,646 28,836 1 278,616 123,163 155,453 28,836 1 il 278,611 124,407 154,203 28,836 183,039 278,549 125,651 152,897 28,836 181,733 278,431 126,896 151,535 28,836 180,371 278,256 128,140 150,116 28,836 178,952 278,025 129,384 148,641 28,836 177,477 277,737 130,628 147,110 28,836 175.946 277,394 131,872 145,522 28,836 1 , 276,993 133,116 143,878 28,836 172,713 276,537 134,360 142,177 28,836 171,013 276,024 135,604 140,420 28,836 169,256 275,454 136,848 138,606 28,836 167,442 274,828 138,092 136,736 28,836 165,572 274,146 139,336 134,810 28,836 163,646 273,408 140,580 132,827 28,836 161,663 272,613 141,824 130,788 28,836 159,624 271,761 143,068 128,693 28,836 157,529 270,853 144,313 126,541 28,836 155,377 269,889 145,557 124,333 28,836 153,168 268,869 146,801 122,068 28,836 150,904 267,792 148,045 119,747 28,836 148,583 266,658 149,289 117,369 28,836 146,205 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 5 of 5 FAA detentn NP2 App. E-19 Existing C 1 A Q in/hr acres cfs 1.82 60.9 Proposed input C 1 A Q constant calculated from other cell in/hr acres cfs 0.37 2.80 typical tables . e.," C values from for Rational Method coefficients I values from NOAA River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 1 of 5 Rat Method SP1 App. E-20 Based on FAA method in Handbook o Hydrology, p. 28.27 Qout = Qin = Qout/Qin = k= Runoff coeff Impervious 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 IMF Area A acres 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 22.17 63.09 1 0.35 1.50 storm Rainfall duration intensity T min in/hr 5 5.39 6 5.15 7 4.91 8 4.67 9 4.43 10 4.19 11 4.06 12 3.93 13 3.79 14 3.66 15 3.53 16 3.46 17 3.39 18 3.31 19 3.24 20 3.17 21 3.10 22 3.03 23 2.95 24 2.88 25 2.81 26 2.74 27 2.67 cfs (historic) Impervious Ratio cfs (developed) Drain Time (hr) WQCV (in) (from graph) storage factor (sf) 0.32 40 0.157 WQ Volume Volume Volume Volume Total runoff minus CIAT k(Qout)T outflow (WQCV/12)*A*sf cuft cuft cuft cuft cu ft From UDFCD Manual Vol. 3 Figure EDB -2 92,345 9,975 82,370 34,708 117,077 105,880 11,971 93,910 34,708 128,617 4 117,770 13,966 103,805 34,708 138,512 128,015 15,961 112,055 34,708 146,762 136,616 17,956 118,660 34,708 153,368 143,572 19,951 123,621 34,708 158,329 152,954 21,946 131,008 34,708 165,715 161,431 23,941 137,490 34,708 172,198 169,004 25,936 143,068 34,708 177,775 175,672 27,931 147,741 34,708 182,448 181,435 29,926 151,509 34,708 1 189,584 31,921 157,662 34,708 197,238 33,916 163,322 34,708 198,030 204,400 35,912 168,488 34,708 203,196 211,068 37,907 173,161 34,708 207,869 217,243 39,902 177,341 34,708 212,048 222,924 41,897 181,027 34,708 215,734 228,112 43,892 184,220 34,708 21 927 232,806 45,887 186,919 34,708 2 , 237,007 47,882 189,125 34,708 223,832 240,714 49,877 190,837 34,708 225,545 243,928 51,872 192,056 34,708 226,764 246,649 53,867 192,782 34,708 227, input 1 constant calculated from other cell River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 2 of 5 FAA detentn SP1 App. E-21 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 28 2.59 29 2.52 30 2.45 31 2.42 32 2.39 33 2.36 34 2.33 35 2.30 36 2.27 37 2.24 38 2.21 39 2.18 40 2.15 41 2.12 42 2.09 43 2.06 44 2.03 45 2.00 46 1.97 47 1.94 48 1.91 49 1.88 50 1.85 51 1.82 52 1.79 53 1.76 54 1.73 55 1.70 56 1.67 57 1.64 58 1.61 248,876 55,862 193,014 34,708 227,722 250,610 57,857 192,753 34,708 227,460 251,851 59,853 191,998 34,708 226,706 257,059 61,848 195,211 34,708 229,919 262,062 63,843 198,219 34,708 232,926 266,859 65,838 201,021 34,708 235,729 271,450 67,833 203,618 34,708 238,325 275,836 69,828 206,008 34,708 240,716 280,017 71,823 208,194 34,708 il 283,992 73,818 210,173 34,708 2 ; 287,761 75,813 211,948 34,708 246,655 291,324 77,808 213,516 34,708 248,224 294,682 79,803 214,879 34,708 249,586 297,835 81,798 216,036 34,708 250,744 300,782 83,794 216,988 34,708 251,696 303,523 85,789 217,734 34,708 252,442 306,058 87,784 218,275 34,708 252,9 308,388 89,779 218,610 34,708 253,317 310,513 91,774 218,739 34,708 253,447 312,432 93,769 218,663 34,708 253,370 314,145 95,764 218,381 34,708 253,089 315,653 97,759 217,894 34,708 252,601 316,955 99,754 217,201 34,708 251,908 318,051 101,749 216,302 34,708 251,010 318,942 103,744 215,198 34,708 249,905 319,628 105,739 213,888 34,708 248,596 320,107 107,735 212,373 34,708 247 8 320,381 109,730 210,652 34,708 2 , 320,450 111,725 208,725 34,708 243,433 320,313 113,720 206,593 34,708 241,301 319,970 115,715 204,255 34,708 238,963 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 3 of 5 FAA detentn SP1 App. E-22 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 59 1.58 60 1.55 61 1.54 62 1.53 63 1.52 64 1.51 65 1.49 66 1.48 67 1.47 68 1.46 69 1.45 70 1.44 71 1.43 72 1.42 73 1.40 74 1.39 75 1.38 76 1.37 77 1.36 78 1.35 79 1.34 80 1.33 81 1.32 82 1.30 83 1.29 84 1.28 85 1.27 86 1.26 87 1.25 88 1.24 89 1.23 319,422 117,710 201,712 34,708 236,419 318,668 119,705 198,963 34,708 233,671 321,645 121,700 199,945 34,708 234,653 324,546 123,695 200,851 34,708 235,558 327,370 125,690 201,679 34,708 236,387 330,117 127,685 202,432 34,708 237,139 332,788 129,680 203,108 34,708 237,815 335,383 131,676 203,707 34,708 238,415 337,901 133,671 204,230 34,708 340,342 135,666 204,676 34,708 342,707 137,661 205,046 34,708 239,754 344,995 139,656 205,339 34,708 240,047 347,207 141,651 205,556 34,708 240,264 349,342 143,646 205,696 34,708 240,404 351,401 145,641 205,760 34,708 240,468 353,383 147,636 205,747 34,708 240,455 355,289 149,631 205,658 34,708 240,3 357,118 151,626 205,492 34,708 240,200 358,871 153,621 205,250 34,708 239,957 360,547 155,617 204,931 34,708 362,147 157,612 204,535 34,708 2 363,670 159,607 204,063 34,708 238,771 365,117 161,602 203,515 34,708 238,222 366,487 163,597 202,890 34,708 237,597 367,780 165,592 202,188 34,708 236,896 368,997 167,587 201,410 34,708 236,118 370,138 169,582 200,555 34,708 235,263 371,201 171,577 199,624 34,708 234,332 372,189 173,572 198,617 34,708 233,324 373,100 175,567 197,532 34,708 232,240 373,934 177,562 196,372 34,708 231,079 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 4 of 5 FAA detentn SP1 App. E-23 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 0.93 90 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 60.9 90 1.22 91 1.20 92 1.19 93 1.18 94 1.17 95 1.16 96 1.15 97 1.14 98 1.13 99 1.11 100 1.10 101 1.09 102 1.08 103 1.07 104 1.06 105 1.05 106 1.04 107 1.03 108 1.01 109 1.00 110 0.99 111 0.98 112 0.97 113 0.96 114 0.95 115 0.94 116 0.92 117 0.91 118 0.90 119 0.89 120 0.88 374,692 179,558 195,134 34,708 229,842 375,373 181,553 193,821 34,708 228,528 375,978 183,548 192,430 34,708 227,138 376,506 185,543 190,964 34,708 225,671 376,958 187,538 189,420 34,708 224,128 377,333 189,533 187,800 34,708 222,5 377,632 191,528 186,104 34,708 220,811 377,854 193,523 184,331 34,708 219,038 378,000 195,518 182,482 34,708 2 378,069 197,513 180,556 34,708 378,061 199,508 178,553 34,708 213,261 377,977 201,503 176,474 34,708 211,181 377,817 203,499 174,318 34,708 209,026 377,580 205,494 172,086 34,708 206,794 377,266 207,489 169,778 34,708 204,485 376,876 209,484 167,393 34,708 20210 376,410 211,479 164,931 34,708 1 , 375,867 213,474 162,393 34,708 197,100 375,247 215,469 159,778 34,708 194,486 374,551 217,464 157,087 34,708 191,794 373,778 219,459 154,319 34,708 189,027 372,929 221,454 151,475 34,708 186,182 372,003 223,449 148,554 34,708 183,261 371,001 225,444 145,557 34,708 180,264 369,922 227,440 142,483 34,708 177,190 368,767 229,435 139,332 34,708 174,040 367,535 231,430 136,105 34,708 170- 1 366,227 233,425 132,802 34,708 1 , 364,842 235,420 129,422 34,708 164,129 363,380 237,415 125,965 34,708 160,673 361,842 239,410 122,432 34,708 157,140 River Edge Colorado Water Quality and Quantity Storage Calculations 12/26/2010 5 of 5 FAA detentn SP1 App. E-24 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX F: CDPHE STORMWATER MANAGEMENT PLAN APPLICATION App. F-1 STATE OF COLORADO Dedicated to protecting and improving the health and environment of the people of Colorado 4300 Cherry Creek Dr. $. Denver, Colorado 80246-1530 Phone (303) 692-2000 TDD Line (303) 691-7700 Located in Glendale, Colorado httpa/www.cdphe.slate.co. us Colorado Department of Public Health and Environment For Agency Use Only Permit Number Assigned COR03- Date Received / / Month Day Year STORMWATER DISCHARGE ASSOCIATED WITH CONSTRUCTION ACTIVITIES APPLICATION PHOTO COPIES, FAXED COPIES, PDF COPIES OR EMAILS WILL NOT BE ACCEPTED. Please print or type. Original signatures are required. This application must be considered complete by the Division before it will initiate permit processing. The Division will notify the applicant if additional information is needed to complete the application. If more space is required to answer any question, please attach additional sheets to the application form. Applications must be mailed or delivered to: Colorado Department of Public Health and Environment Water Quality Control Division 4300 Cherry Creek Drive South WQCD-P-B2 Denver, Colorado 80246-1530 PERMIT INFORMATION Applicant is: ❑ Property Owner ❑ Contractor/Operator 1. CONTACT INFORMATION Permit Applicant Company Name: Carbondale Investments, LLC Legally Responsible Person: First Name: Rockwood Last Name: Shepard Title: Project Executive Mailing Address: City, State and Zip Code: Phone: Email Address: See description of legal contact item 9, page 3 5121 Park Lane Dallas, TX 75220 Local Facility Contact nSame as Applicant Local Contact Person: First Name: Rockwood Last Name: Shepard Title: Project Executive Phone: (970) 945-2113 Email Address: rshepard@westpacinv.com Billing Contact n Same as Applicant Company Name: Carbondale Investments, LLC Billing Contact Person: First Name: Rockwood Last Name: Shepard Title: Project Executive Mailing Address: 7999 Hwy. 82 City, State and Zip Code: Carbondale, CO 81623 Phone: (970) 945-2113 Email Address: App. F-2 Page 1 of 3 Revised 12/2010 1. CONTACT INFORMATION - CONTINUED Assignment Of Authorized Agent(S)—Regulation 61 [61.4(1)] NOT REQUIRED In accordance with Regulation 61, all reports required by permits and other information requested by the Division shall be signed by a person described in section 61.4(1)(e) or by a duly authorized representative of that person. A person is a duly authorized representative only if: i. The authorization is made in writing by a person described in paragraph 61.4(1)(e); ii. The authorization specifies either an individual or a position having responsibility for the overall operation of the regulated facility or activity such as the position of plant manager, operator of a well or a well field, superintendent, position of equivalent responsibility, or an individual or position having overall responsibility for environmental matters for the company. (A duly authorized representative may thus be either a named individual or any individual occupying a named position); and, iii. The written authorization is submitted to the Division. Duly Authorized Representative information provided below? ❑ NO a YES Authorized individual: Rockwood Shepard Email address: rahepard@westpacinv.com Title: Project Executive Telephone No: (970) 945-2113 Authorized position: Email address: Position currently held by: Telephone No: 2. PERMITTED FACILITY INFORMATION Name of Plan, Project or Development: River Edge Colorado Location of construction site: Street Address (or cross streets): 7999 Hwy. 82 City (if unincorporated, so indicate): Carbondale County:Garfield State and Zip Code: Colorado, 81623 Latitude and Longitude (approximate center of site to nearest 15 seconds using one of following formats): Latitude: Longitude: (e.g., 39°42'11", 104°55'57") degrees /minutes/ seconds degrees/ minutes/ seconds OR Latitude: Longitude: (e.g., 39.703°, 104.933') degrees (to 3 decimal places) degrees (to 3 decimal places) 3. MAP (Attachment) Map: Attach a map that indicates the site location and that CLEARLY shows the boundaries of the area that will be disturbed. Maps must be no larger than 11x17 inches. 4. LEGAL DESCRIPTION Legal description: If subdivided, provide the legal description below, or indicate that it is not applicable (do not supply Township/Range/Section or metes and bounds description of site) Subdivision(s): Lot(s): Block(s): OR o Not applicable (site has not been subdivided) 5. AREA OF CONSTRUCTION SITE Total area of project site (acres): 159.16 Area of project site to undergo disturbance (acres): 159.16 Total disturbed area of Larger Common Plan of Development or Sale, if applicable: 159.16 (i.e., total, including all phases, filings, lots, and infrastructure not covered by this application) App. F-3 Page 2 of 3 Revised 12/2010 6. NATURE OF CONSTRUCTION ACTIVITY Check the appropriate box(s) or provide a brief description that indicates the general nature of the construction activities. (The full description of activities must be included in the Stormwater Management Plan.) in Single Family Residential Development ❑ Multi -Family Residential Development ❑ Commercial Development ❑ Oil and Gas Production and/or Exploration (including pad sites and associated infrastructure) ❑ Highway/Road Development (not including roadways associated with commercial or residential development) n Other, Describe: 7. ANTICIPATED CONSTRUCTION SCHEDULE Construction Start Date: Final Stabilization Date: 8. RECEIVING WATERS (If discharge is to a ditch or storm sewer, include the name of the ultimate receiving waters) Immediate Receiving Water(s): Roaring Fork River Ultimate Receiving Water(s): Colorado River 9. REQUIRED SIGNATURES (Both parts i. and ii. must be signed) Signature of Applicant: The applicant must be either the owner and/or operator of the construction site. Refer to Part B of the instructions for additional information. The application must be signed by the applicant to be considered complete. In all cases, it shall be signed as follows: (Regulation 61.4 (lei) a) In the case of corporations, by the responsible corporate officer is responsible for the overall operation of the facility from which the discharge described in the form originates b) In the case of a partnership, by a general partner. c) In the case of a sole proprietorship, by the proprietor. d) In the case of a municipal, state, or other public facility, by either a principal executive officer, ranking elected official, (a principal executive officer has responsibility for the overall operation of the facility from which the discharge originates). STOP!: A Stormwater Management Plan must be completed prior to signing the following certifications! Stormwater Management Plan Certification "I certify under penalty of law that a complete Stormwater Management Plan, as described in Appendix A of this application, has been prepared for my activity. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the Stormwater Management Plan is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for falsely certifying the completion of said SWMP, including the possibility of fine and imprisonment for knowing violations." Signature of Legally Responsible Person or Authorized Agent (submission must include original signature) Date Signed Name (printed) Title ii. Signature of Permit Legal Contact "I certify under penalty of law that I have personally examined and am familiar with the information submitted in this application and all attachments and that, based on my inquiry of those individuals immediately responsible for obtaining the information, I believe that the information is true, accurate and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine or imprisonment. "I understand that submittal of this application is for coverage under the State of Colorado General Permit for Stormwater Discharges Associated with Construction Activity for the entirety of the construction site/project described and applied for, until such time as the application is amended or the certification is transferred, inactivated, or expired." Signature of Legally Responsible Person (submission must include original signature) Date Signed Name (printed Title DO NOT INCLUDE A COPY OF THE STORMWATER MANAGEMENT PLAN DO NOT INCLUDE PAYMENT — AN INVOICE WILL BE SENT AFTER THE CERTIFICATION IS ISSUED. App. F-4 Page 3 of 3 Revised 12/2010 Erosion and Sediment Control Plan River Edge Colorado, Garfield County, Colorado APPENDIX G: WETLANDS DELINEATION REPORT App. G-1 Balanced solutions to complex environmental issues. Wetland Delineation River Edge Colorado Garfield County, Colorado September 2010 Prepared for: River Edge Colorado and U.S. Army Corps of Engineers Colorado West Regulatory Office po box 1095 frisco co 80443 1 970.309.4454 info©pendosolutions.com 1 www. pendosolutions.com solution App. G-2 River Edge Colorado Wetland Determination Report September 7, 2010 Wetland Delineation Report for River Edge Colorado Garfield County, Colorado TABLE OF CONTENTS 1. INTRODUCTION 3 1.1. Contact Information 3 1.2. Project Location 3 1.3. Figure 1: River Edge Colorado Property Location 4 1.4. Figure 2: Topographic Map of Project Area 5 1.5. Background Information 6 2. METHODS 7 2.1. Wetland Determinations 7 3. RESULTS AND DISCUSSION 9 3.1. Upland Disturbed Area Communities (Non Wetlands) 9 3.2. Lower Bench Riparian Areas (Non -Wetlands) 10 3.3. Cattle Creek Wetlands (Jurisdictional Wetlands) 11 3.4. Riparian Shrublands (Jurisdictional Wetlands) 11 3.5. West Bank Emergent Wetlands (Jurisdictional Wetlands) 12 4. WETLAND FUNCTIONS, VALUES, AND JURISDICTIONAL EXTENT 13 4.1. Figure 3: Map of Jurisdictional Wetlands along Cattle Creek 14 4.2. Figure 4: Map of Jurisdictional Wetlands along Roaring Fork River 15 5. SELECTED REFERENCES 16 6. APPENDIX A- DATA POINT PHOTOGRAPHS 17 7. APPENDIX B- FIELD DATA FORMS 21 8. APPENDIX C: JURISDICTIONAL DETERMINATION- CATTLE CREEK 60 9. APPENDIX D: JURISDICTIONAL DETERMINATION- ROARING FORK RIVER 68 2 PENDO sc)ILticpris App. G-3 River Edge Colorado Wetland Determination Report September 7, 2010 1. Introduction Carbondale Investments, LLC is proposing to develop the property known as River Edge Colorado as a residential community, which precipitated the need for a wetland delineation to assist with their planning efforts. The current proposal includes —975 units, with associated roads and infrastructure. Additional amenities include an elementary school, neighborhood parks and athletic fields, and a community center. The Roaring Fork Trails Association (RFTA) has an existing recreation path that traverses the property from north to south; this path will remain and be enhanced with this proposal. Mr. Sam Otero of 8,140 Partners requested that PENDO Solutions, Inc. (Pendo) delineate a wetland boundary on the property in order to facilitate their planning process, and in anticipation of submitting a permit application for compliance with Section 404 of the Clean Water Act. Pendo will be preparing the 404 application for ACOE review after the Jurisdictional Determination is approved by the ACOE. Portions of Cattle Creek and the Roaring Fork River were targeted for wetland delineations where the project may impinge upon wetlands. Not all wetlands across the property were delineated due to avoidance of large potential wetland areas by the project. 1.1. Contact Information Applicant Rockwood Shepard WestPac Investments 7999 Hwy. 82 Carbondale CO 81623 970-456-5325 970-945-2113 rshepard@westpacinv.com Project Planner/Engineer W. Sam Otero 8140 Partners, LLC PO Box 0426 Eagle, CO 81631 970-445-8810 sam.otero@8140partners.com Authorized Agent Eric Petterson PENDO Solutions, Inc. PO Box 833 Glenwood Springs, CO 81602 970-945-9558 epetterson@pendosolutions.com 1.2. Project Location River Edge Colorado 7999 Hwy. 82 Carbondale, CO 81623 The property is located at an elevation of 6,350 feet between Glenwood Springs and Carbondale in Garfield County, Colorado (Sections 7 & 18, Township 7 South, Range 88 West; and Sections 1, 12 and 13, Township 7 South, Range 89 West, 6th Principal Meridian), west of Highway 82 along Cattle Creek and the Roaring Fork River. The area is within the Cattle Creek USGS Topographic Quadrangle (Figures 1-2). 3 PENDO sc lutic n App. G-4 39°30'0"N 39°20'0"N 0 107°20'0"W 107°10'0"W 107°0'0"W 106°50'0"W 39°30'0"N 39°20'0"N kRiver Edge Colorado Municipal Boundary nCounty Boundary Interstate ."-j State Highway FIGURE 1 River Edge Colorado Project Location 0 s 10 20 Scale: 1"= 10 Mi. Prepared By: PENDO solutions Prepared For: River Edge Colorado App. G-5 CO Of N N m z 0 107°17'0"W 107'16'0"W 107°15'0"W NAN 43.V 110011 re' vs to tAr _ N Homeowners,Assooanon aGAspen Glen Aspen GlenWater&Sanitation District Ra k Wate&\antl atton District � r�G � �isn 107°17'0"W ' ‘1/4 It Af II mr41) 1210111b. API 107°16'0"W 107°15'0"W River Edge Colorado Conservation Easement Parcel Boundary ElTownship Section Stream FIGURE 2 River Edge Colorado Existing Topography 0 1,000 2,000 4,000 Scale: 1"= 2,000' Prepared By: PENDO solutions Prepared For: River Edge Colorado Contour Interval: 10ft. App. G-6 River Edge Colorado Wetland Determination Report September 7, 2010 1.5. Background Information The 282.7 acre project area is bisected by Cattle Creek which flows into the Roaring Fork River. Wetlands were delineated along portions of Cattle Creek and along the Roaring Fork River as requested by the Applicant. The property owners and their representatives are proposing the development of a 945 -unit residential subdivision on the property. As part of this project, utility lines (wastewater and electrical) would likely bisect jurisdictional wetlands and various components of the project may impinge upon some wetland areas. Therefore a wetland delineation was requested for planning purposes, with any needed 404 permitting to follow later in 2010 or 2011. The property is currently vacant land. Historically the property was part of a cow/calf operation with widespread irrigated pasturelands and wintertime grazing. During the summer of 2005, a previous owner began grading of the site for the development of a golf -course and residential community. Midway through grading, the project was terminated, which left the majority of the property with a cobbly surface. Topsoil was salvaged by this early grading process, and stored in large piles. Upland areas are now dominated by ruderal weeds and opportunistic plants including yellow sweetclover (Melilotus officinale), prickly lettuce (Lactuca serriola), and alfalfa (Medigaco sativa). On steeper slopes, and where topsoil salvage operations did not occur, remnant native species occur, including Gambel's oak (Quercusgambelit), sagebrush (Artemisia tridentata ssp. pauciflora), smooth brome (Bromus inermis), timothy (Phleumpratense) and weeds such as plumeless thistle (Carduus acanthoides), and Canada thistle (Cirsium arvense). Older narrowleaf cottonwood trees (Populus angustifolia) which likely established during the long-term irrigation of the meadows are rapidly declining in the absence of irrigation waters. Cattle Creek itself was significantly impacted by historic grazing practices (as interpreted from historical aerial photos). Subsequently the non-native reed canary grass (Phalaroides arundinacea) has become entrenched along this creek. The Roaring Fork Conservancy holds a conservation easement on portions of the property along Cattle Creek and along the Roaring Fork River. While this easement prohibits development, it does allow for the installation of linear utility lines. On the western side of the Roaring Fork River the property is owned by the Homeowners Association of Aspen Glen, and the Roaring Fork Water and Sanitation District. The Roaring Fork Water and Sanitation waste water treatment plant is located here, and River Edge Colorado's plans include a proposed tie-in to this facility for the treatment of wastewater. In anticipation of this, 8140 Partners requested Pendo to delineate wetlands in this area. The wide and well established wetlands in this area appeared to be supported by waters discharged from a pipe, as well as a number of seeps and springs. A total of approximately 6.52 acres of Jurisdictional Wetlands were identified within the targeted areas of the property, and as previously mentioned there are additional wetlands on the property that were not delineated as the project would not be in proximity to these other wetlands. The Federal Clean Water Act, Section 404, authorizes the Corps, specifically the Chief of Engineers, to issue permits for the discharge of dredged or fill materials into navigable Waters of the U.S. This permitting process is overseen by the Environmental Protection Agency and is reviewed by the Fish and Wildlife Service and the National Marine Fisheries Service. This permit requires that the limits of wetlands be identified and delineated. The resulting wetlands are referred to as jurisdictional wetlands and are regulated under Section 404 of the Federal Clean Water Act. The determination of navigability is left entirely to the Corps. 6 PE IDO sc li-AticDga G_7 River Edge Colorado Wetland Determination Report September 7, 2010 2. Methods The wetlands delineation described in this document was conducted following technical guidelines set forth in the U.S. Army Corps of Engineers (Corps) 2008 Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region and the guidance document "Information Needed for Jurisdictional Determinations." Prior to and during field work, PENDO Solutions' (Pendo) staff reviewed various resources to assist in identifying Waters of the U.S., beyond wetland areas located on the property. These resources included aerial photographs, topographic and soils maps, and other environmental resources. Upon completion of the pre -field work, the project area was traversed in August 2010. A total of six data points were used along Cattle Creek (three points in uplands and three points in wetlands). Six sample points were used along the Roaring Fork River and associated wetlands. Wetland sample points revealed the boundary between sites which exhibited all three wetland parameters and sites which were lacking one or more wetland parameters. Based on the presence or absence of parameters, wetland boundaries were designated. Ecosystem parameters (vegetation, soils, and hydrology) were characterized and recorded on field data forms (Appendix B) at each of the twelve sample points. Based on observations of all three wetland parameters, wetland boundaries were designated with pink wetland delineation flagging. Wetland boundaries were then logged with a Trimble GeoXT GPS unit (sub -meter accuracy), differentially corrected, and then exported as ArcGIS shapefiles. Wetland boundaries are depicted on Figures 3 & 4. 2.1. Wetland Determinations Wetland Determinations were performed as outlined in the 2006 Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region. The wetlands on the site are hydrologically connected to Cattle Creek and the Roaring Fork River, both of which are perennially flowing streams immediately upstream of the Colorado River. The wetlands associated with the bottomlands along the Roaring Fork River are hydrogeomorphically classed as Riverine Wetlands, with Riverine Subclass designations of 3 and 4 (middle -elevation reaches of small and mid -order streams, dominated by tall shrubs and trees). • Vegetation: Vegetation was sampled throughout the site and in vicinity of the sample points. An attempt was made to identify all dominant species, and species were listed in order of dominance. A wetland indicator status for each species was determined using the National List of Plant Species that Occur in Wetlands: Intermountain (Region 8) (USFWS, 1988), and if the species was not addressed in that report, then the National Hydric Plant List was referenced. Cover for each species was estimated to the nearest percent to determine dominance. • Soils: Soil pits were dug in wetlands and non -wetlands at each site and inspected for hydric characteristics. Hydric characteristics included saturated soils and standing water in soil pits among other indicators. Mottling and sulphidic odors were observed. Soils in the wetland areas are described as (Soil Conservation Service 1981): o Jodero Loam, 1-12% slopes. This deep, well drained soil is found on alluvial valley floors at elevations ranging from 5,700 to 7,500 feet and on slopes of 1 to 12 percent. It is derived from alluvium composed of andesite, sandstone, and shale. 7 TENDO sc)IL.a t icer App. G-8 River Edge Colorado Wetland Determination Report September 7, 2010 Surface runoff for this soil is slow to medium and the water erosion hazard is slight to severe. o Redrob loam, 1-6% slopes. These are deep, somewhat poorly drained soils on alluvial valley floors, low terraces, and floodplains, formed in mixed alluvium derived dominantly from sandstone and shale. Typically the surface layer is dark grayish - brown loam about 14 inches thick, the next layer is stratified stony loam about six inches thick, and the substratum to a depth of 60 inches is stony and very cobbly loamy sand and sand. The high water table is at a depth of 18-48 inches. This soil type is found on the lower bench, occupying the southwest corner of the property. • Hydrology: The site was traversed making observations for hydrologic characteristics. Cattle Creek flows into the Roaring Fork River and then the Colorado River, and are therefore Waters of the U.S. Wetland and upland communities were classified based on dominant vegetation characteristics. A field copy of the Arid Land Wetland Determination Data Form was completed for each sample point. This form recorded the vegetation, soil, and hydrologic measurements and observations. Latin plant names were used throughout. Based on the information recorded in the Data Forms, each community that met all three wetland criteria was established as a wetland. 8 TENDO sc. )lutioga G-9 River Edge Colorado Wetland Determination Report September 7, 2010 3. Results and Discussion 3.1. Upland Disturbed Area Communities (Non Wetlands) Vegetation: The majority of the property lies on an old river terrace that lies about 75 feet above the Roaring Fork River. The type of species that are present on the disturbed upper areas of the property depends upon the underlying soil texture. The finer soils and topsoil stockpiles on the property are dominated by cheatgrass (Bromus tectorum -NI), stork's bill (Erodium cicutarium- NI), and Jim Hill mustard (Siymbrium altissimum- FACU). The noxious weeds such as Scotch thistle (Onopordum acanthium-NI), plumeless thistle (Carduus acanthoides-NI), common burdock (Arctium minus - NI), and common tansy (Tanacetum vulgare- FACW) are widespread, but occur in relatively sparse densities and the current landowners have been spraying weeds. Field bindweed (Convolvulus arvensis - NI) is very common within this area. The more coarse textured soils on the upper bench of the property are dominated by patchy, sparse stands of narrow leaf cottonwood (Populus angustifolia- FACW), yellow sweet clover (Melilotus ofcinalis-FACU), and common mullein (Verbascum Thapsus- NI). Soils: The soils in this area were typed by the National Resource Conservation Service (NRCS) as Jodero Loams, but much of the broader tablelands are dominated by Atencio-Azeltine complex soils, but given the topsoil salvage, much of soils have been significantly disturbed outside of the wetland areas. No concretions were detected, nor did the soils have any sulphidic odors. It is likely that if a soil pit was dug in some of the depressions, mottling would be detected. Hydrology: We did not detect hydrological indicators outside of wetland areas. The main feature absent in uplands, which was present in wetlands was soil saturation. Determination: The Upland Disturbed Area Communities failed to support hydric soil indicators and hydrology, while some extension of hydric vegetation occurred near Cattle Creek. Upland areas did not meet the criteria as a wetland. 9 PENDO scpitic ,pa 10 River Edge Colorado Wetland Determination Report September 7, 2010 3.2. Lower Bench Riparian Areas (Non -Wetlands) Vegetation: The lower bench of the property is directly adjacent to the Roaring Fork River. In most regions of the property the slope down to the river is exceedingly steep and is dense with woody vegetation such as ponderosa pine (Pinus ponderosa- FACU), Rocky Mountain juniper (Jun perus scopulorum- UPL), and oakbrush (Quercus gambelii-NI). In some regions of the property, these steep slopes are directly adjacent to the river. In other places, river bottom/ riparian vegetation communities are present in areas of prolonged sediment deposition as a result of river configuration and water flow dynamics. Noxious weeds are both dense and abundant in the riparian areas. Species include Scotch thistle, houndstongue (Cynoglossum ofcinale- FACU), oxeye daisy (Chrysanthemum leucanthemum-NI), plumeless thistle, common burdock (Arctium minus-FACU), Canada thistle (Cirsium arvense-FACU), common tansy (FACU), and St. John's wort (Hypericum perfoliatum). These areas are held under a Conservation Easement by the Roaring Fork Conservancy. Soils: The soils in this area were typed by the NRCS as Atencio/Azeltine complex, but seemed to trend more towards Redrob cobbly loams. There was no mottling, sulphidic odor or other attributes of wetland soils. Hydrology: These areas failed to exhibit wetland indicators such as saturation, drift lines or free water, which were common in wetland areas. Determination: The Lower Bench Riparian areas, while having some narrowleaf cottonwood and extensions of coyote willow failed to have sufficient dominance by hydric vegetation, and did not support hydric soils or wetland hydrology, leading to a determination that the site is not a jurisdictional wetland. 10 TENDO scDiLr�c,pa �� River Edge Colorado Wetland Determination Report September 7, 2010 3.3. Cattle Creek Wetlands (Jurisdictional Wetlands) Vegetation: The site was dominated (>95% cover) by reed canarygrass (Phalaroides arundinaceae- OBL), with insignificant amounts of common tansy (Tanacetum vulgare- FACU), Canada thistle (Cirsium arvense-FACU), and horsemint (Mentha arvensis- FACW). The site was dominated by hydrophitic vegetation. Soils: The soils in this area were typed by the NRCS as Jodero Loams complex. Within these areas saturation was detected within 12 inches of the surface. Mottling was light but nevertheless present and sulphidic odors were very limited. Hydric soil indicators were present in these areas Hydrology: Hydrology for the site was apparent through saturation, drift (wrack) lines, and sometimes free water. Determination: The Cattle Creek Wetlands were primarily determined by the dominance of reed canary grass (OBL) hydrology and hydric soils. Cattle Creek's observed consistent and steady flows have created a fairly constrained channel, with surface waters often a foot or more below the adjacent riparian (wetland) community types. Nevertheless the creek does support a narrow band of wetlands along either side of the creek. 3.4. Riparian Shrublands (Jurisdictional Wetlands) Vegetation: Along the banks of the Roaring Fork River riparian shrublands dominated by silver buffaloberry (Shepherdia argentea-FACU), hawthorne (Cratagus saligna- FACW), coyote willow (Salix exigua- FACW), and understory vegetation including mannagrass (Glyceriagrandis-OBL) and Baltic rush (Pincus balticus-FACW). Another species of note was Ute ladies -tresses orchid (Spiranthes diluvialis) which is listed by the U.S. Fish and Wildlife Service as Threatened. The site had an abundance of hydrophitic vegetation. Soils: The soils in this area were typed by the NRCS and confirmed as Jodero loams. Within these wetlands, soils were generally saturated and surface waters were patchy. Along the wetland gradient, saturation and standing water gradually dropped out of the bottom of test pits. Mottling was light. The site supported hydric soil indicators. Hydrology: Hydrology for the site is generally assumed to be from the Roaring Fork however, 11 FENEDO iuticAr 12 River Edge Colorado Wetland Determination Report September 7, 2010 some subsurface hydrology from irrigation return flows near the water treatment facilities are likely. The site had an abundance of wetland hydrologic indicators. Determination: The Riparian Shrublands had hydrophitic vegetation, hydric soils, and wetland hydrology, leading to a determination that the site was a jurisdictional wetland. The combination of seasonal high flows from the Roaring Fork River supported this community type along both the east and west banks of the river. On the west bank additional hydrology supported a wider and more diverse stand type, which graded into the Bench Wetlands area (see below). 3.5. West Bank Emergent Wetlands (Jurisdictional Wetlands) Between the Roaring Fork Water & Sanitation District's water treatment plant on the west side of the Roaring Fork and the Roaring Fork itself, there is a broad, shallow de.ression on a riverside terrace that is fed by assumed irrigation return flows, or discharged treated waters from the wastewater treatment site. Additionally there are a number of springs and seeps feeding this area. Wetlands in this area were located on property owned by the Homeowners Association at Aspen Glen and Roaring Fork Water and Sanitation District. Vegetation: Cattails (Typha latifolia-FACW), reed canarygrass (Phalaroides arundinacea- OBL), and wooly sedge (Carex lanuginose-OBL), redtop (Agrostis alba- FACW), and Nebraska sedge (Carex nebraskensis- OBL). The site was dominated by hydrophitic vegetation. Soils: The soils in this area were typed by the NRCS and confirmed as Jodero loams. Within this area, soils were generally moist and with saturation within 12 inches of the surface and had low chromas. Some light mottling and sulphidic odors were also detected. Hydrology: The site was fed by a large pipe discharging water from near the water treatment plant. It is unknown if this water is from the plant, or if there was also irrigation return flows. Around the western perimeter of the wetlands there was also many springs and seeps. Saturation and inundation was common. Determination: The emergent wetlands on the west bank showed surface water connectivity directly to the Roaring Fork River and supported the three parameters for jurisdictional wetlands. This site was very extensive and supported emergent wetlands which graded into a more shrub -dominated wetland type along the banks of the Roaring Fork River. 12 PENIDO sc'IL 1 App. G-13 River Edge Colorado Wetland Determination Report September 7, 2010 4. Wetland Functions, Values, and Jurisdictional Extent The ecological functions of wetlands on the project site were assessed preliminarily using an approach based on the hydrogeomorphic methodology (HGM), which assesses the potential for a wetland to perform ecological functions. These functions include dynamic water storage, flood flow attenuation, production export, nutrient and pollutant removal/sediment retention, shoreline stabilization/ sediment control and wildlife habitat. The ability and the extent to which each wetland is able to perform these functions yield an overall impression of wetland functions and its value. The results of this analysis within the project area revealed that wetlands delineated in the Cattle Creek area are likely valued as low functioning wetlands. The dominance of reed canary grass and lack of vegetation diversity significantly limits the wildlife habitat value of the site. However, the extremely thick stand of reed canary grass is definitely providing bank stability and flood attenuation capacity. Along the banks of the Roaring Fork the combination of both emergent wetlands and riparian shrub -dominated wetlands provides for more diverse wildlife and plant habitat, and indeed the site contains the Federally listed Ute ladies -tresses orchid (Spiranthes diluvialis). Along this area there is also a great blue heron heronry, and osprey and bald eagle are frequently observed in this area. Wetlands are providing important bank stability and wildlife habitat values, as well as flood attenuation. However, during the spring of 2010 very high spring flows eroded a portion of the bank and dislodged a large ponderosa pine which further unraveled western banks along the Roaring Fork, so long-term bank stability in this area is concerning. In summary the vegetation, soil, and hydrologic data gathered in this survey determined that wetlands occurred on the River Edge Colorado property, and that hydrological surface connectivity to Waters of the U.S. was present. Cattle Creek is considered to be a Water of the US (ACOE 2007), as well as the Roaring Fork River. Wetlands identified on the property were adjacent and abutting to these rivers. Final authority in determining the actuality of a wetland and the allowance of wetland alterations rests with the various interested government agencies. Eroding banks and large ponderosa pine tree that fell in spring high -flows in 2010. 13 FENDO SC.DIL.IticArp _14 39°27'30" 39°27'20"N 107°16'0"W 107°15'50"W 107°16'0"W 107°15'50"W River Edge Colorado Parcel Boundary Wetland • Data Point FIGURE 3 River Edge Colorado Wetlands Cattle Creek 0 150 300 600 Scale: 1"= 300' Prepared By: PENDO solutions Prepared For: River Edge Colorado Contour Interval: 2 ft. App. G-15 107°16'10"W ''E,nd\of Proper, - „\_ 107°16'0"W 0 Sp Homeowners Associa "•n at Aspen Glen Aspen GIeneater & Sanitation District 1 107°16'10"W River Edge Colorado Parcel Boundary Wetland • Data Point 107°16'0"W 39°27'10"N FIGURE 4 River Edge Colorado Wetlands Roaring Fork 0 100 200 400 Scale: 1'= 200' Prepared By: PENDO solutions Prepared For: River Edge Colorado Contour Interval: 2 ft. App. G-16 River Edge Colorado Wetland Determination Report September 7, 2010 5. Selected References Cooper, D.J. 1989. A Handbook of Wetland Plants of the Rocky Mountain Region. EPA Region VIII. Dorn, R.D. 1997. Rocky Mountain region willow identification field guide. Renewable Resources R2 -RR -97-01. Denver, CO: USDA, Forest Service, Rocky Mountain Region. 107p. Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual,. Technical Report Y- 87-1, US Army Engineers Waterways Experiment Station, Vicksburg, Miss. Environmental Laboratory. 2006. Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Arid West Region. ERDC/EL TR -06-16. US Army Engineer Research and Development Center. Vicksburg, MS. Federal Interagency Committee for Wetland Delineation. 1989. Federal Manual for Identing and DelineatingJurisdictional Wetlands. U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, U.S. Fish and Wildlife Service, and U.S.D.A. Soil Conservation Service, Washington, D.C. Cooperative technical publication. 76 pp. Plus appendices. Kartesz, J.T. 1996. National List of Plant Species That Occur in Wetlands: Region 8. Ecology Section, National Wetlands Inventory, U.S. Fish and Wildlife Service, Biological Report, Washington, DC. Northwest Colorado Council of Governments. 2006. Transitions in Mountain Communities: Resort Economies and their Secondary Effects. http: / /www.nwc.cog.co.us/Second%20Home%20Study/Second%20phase/2Final%20TMC %20Binder%20May%2007.pdf Spackman, S., B. Jennings, J. Coles, C. Dawson, M. Minton, A. Kratz, and C. Spurrier. 1997. Colorado Rare Plant Field Guide. Prepared for the BLM, USFS, and the USFWS by the Colorado Natural Heritage Program. Weber, W.A. and R.C. Wittmann 2001. Colorado Flora: Western Slope, Third Edition. University Press of Colorado. Boulder, CO. 16 PENDO scltticIrao.G-17 River Edge Colorado Wetland Determination Report September 7, 2010 6. Appendix A- Data Point Photographs 17 PENIDO SCDIUticA,pa _18 River Edge Colorado Wetland Determination Report September 7, 2010 DP -4 Soil Pit (Upland) DP -4 Area DP -5 Soil Pit (Wetland) DP -5 Area DP -6 Soil Pit (Upland) DP -6 Area 18 TENDO sE.'I .j I it. App. G-19 River Edge Colorado Wetland Determination Report September 7, 2010 19 FFNDO sE.'I .j I it. App. G-20 River Edge Colorado Wetland Determination Report September 7, 2010 DP -10 Soil Pit (Wetland) DP -11 Soil Pit (Upland) DP -10 Area DP -12 Soil Pit (Wetland) 20 TENDO scpi j I Ic App. G-21