MOFFAT COLLECTION SYSTEM PROJECT. Denver Water

Transcription

1 VOLUME 1 OF 6 DRAFT ENVIRONMENTAL IMPACT STATEMENT MOFFAT COLLECTION SYSTEM PROJECT Denver Water U.S. Army Corps of Engineers Omaha District Master Table of Contents Acronyms Glossary References Executive Summary Chapter 1 Purpose and Need Chapter 2 Proposed Action and Alternatives October 2009

2 This Environmental Impact Statement (EIS) was prepared by URS Corporation, an environmental and engineering consulting firm, with the guidance, participation, and independent evaluation of the U.S. Army Corps of Engineers (Corps). The Corps, in accordance with 40 Code of Federal Regulations (CFR) (a) and (c), is in agreement with the findings of the analysis, and approves and takes responsibility for the scope and content of this document.

3 DRAFT ENVIRONMENTAL IMPACT STATEMENT MOFFAT COLLECTION SYSTEM PROJECT Denver Water U.S. Army Corps of Engineers Omaha District Martha S. Chieply, Chief REGULATORY BRANCH ARMY CORPS OF ENGINEERS, OMAHA DISTRICT Date October 2009

4 This Environmental Impact Statement (EIS) was prepared by URS Corporation, an environmental and engineering consulting firm, with the guidance, participation, and independent evaluation of the U.S. Army Corps of Engineers (Corps). The Corps, in accordance with 40 Code of Federal Regulations (CFR) (a) and (c), is in agreement with the findings of the analysis, and approves and takes responsibility for the scope and content of this document.

5 Legislative Executive COVER SHEET DRAFT ENVIRONMENTAL IMPACT STATEMENT MOFFAT COLLECTION SYSTEM PROJECT Lead Agency: Department of the Army Corps of Engineers, Omaha District Jurisdictions in Colorado That Could be Directly Affected: City and County of Denver, Adams County, Boulder County, Jefferson County, and Grand County Abstract: This Draft Environmental Impact Statement (EIS) evaluates the effects of a water supply project called the Moffat Collection System Project (Moffat Project). The Moffat Project would result in direct impacts to jurisdictional waters of the United States (U.S.), including wetlands. The placement of fill material in these waters of the U.S. for the construction of water storage and distribution facilities associated with developing additional water supplies requires authorization from the U.S. Army Corps of Engineers (Corps) under Section 404 of the Clean Water Act. The Applicant is the City and County of Denver, acting by and through its Board of Water Commissioners (Denver Water). Denver Water proposes to enlarge its existing 41,811-acre foot (AF) Gross Reservoir by 72,000 AF to a total storage capacity of 113,811 AF. Gross Dam is located in Boulder County, Colorado, approximately 35 miles northwest of Denver and 6 miles southwest of the city of Boulder. The enlargement would be accomplished by raising the existing concrete gravity arch dam by 125 feet, from 340 to 465 feet high. The surface area of the reservoir would be expanded from approximately 418 acres to 818 acres. Using existing collection infrastructure, water from the Fraser River, Williams Fork River, and South Boulder Creek would be diverted and delivered during average to wet years via the Moffat Tunnel and South Boulder Creek to Gross Reservoir. There would be no additional diversions in dry years because Denver Water already diverts the maximum amount physically and legally available under their existing water rights without additional storage in their system. In order to firm this water supply and provide 18,000 AF per year of new firm yield, an additional 72,000 AF of storage capacity is necessary. To meet future demands, in most years, Denver Water would continue to rely on supplies from its entire integrated collection system. In a drought or emergency, Denver Water would rely on the additional water it would have previously stored in the Moffat Collection System to provide the additional 18,000 AF of yield. The purpose of the Moffat Project is to develop 18,000 AF per year of new, annual firm yield to the Moffat Water Treatment Plant (WTP) and raw water customers upstream of the Moffat WTP pursuant to the Board of Water Commissioners commitment to its customers. Denver Water s need for the proposed Moffat Project is to address two major issues: (1) the overall near-term water supply shortage, and (2) the imbalance in water storage and supply between the North and South systems. This EIS analyzes six alternatives for the Moffat Project: (1) Proposed Action (Alternative 1a) Gross Reservoir Expansion (Additional 72,000 AF), (2) Alternative 1c Gross Reservoir Expansion (Additional 40,700 AF)/New Leyden Gulch Reservoir (31,300 AF), (3) Alternative 8a Gross Reservoir Expansion (Additional 52,000 AF)/Reusable Return Flows/Gravel Pit Storage (5,000 AF), (4) Alternative 10a Gross Reservoir Expansion (Additional 52,000 AF)/Reusable Return Flows/Denver Basin Aquifer Storage (20,000 AF), (5) Alternative 13a Gross Reservoir Expansion (Additional 60,000 AF)/Transfer of Agricultural Water Rights/Gravel Pit Storage (3,625 AF), and (6) No Action Alternative, which assumes that Denver Water would not receive approval from the Corps to implement the Moffat Project. Denver Water would rely upon a combination of strategies including using a portion of its Strategic Water Reserve and imposing mandatory restrictions to reduce demand during droughts. EIS Contact for Comments and Additional Information: Scott Franklin, Moffat EIS Project Manager U.S. Army Corps of Engineers, Omaha District Denver Regulatory Office 9307 South Wadsworth Boulevard Littleton, CO moffat.eis@usace.army.mil Date Draft EIS Filed with EPA: October 30, 2009 Date of Public Hearings: December 1, 2, and 3, 2009 Date by Which Comments are Due: January 28, Written comments should be received by close of business, 5 p.m. Please include your name and complete mailing address on all written comments.

6 MASTER TABLE OF CONTENTS Volume 1 of 6 Acronyms... 1 Glossary... 1 References... 1 Executive Summary... ES-1 Chapter 1 Purpose and Need Introduction Project Purpose and Need Statement Denver Water s Preferred Alternative Denver Water s Existing System Raw Water Collection System North System Overview South System Overview Replacement Facilities Non-Potable Recycling Facility Hydropower Generation Implications of Denver Water s Raw Water Collection System and Operations to Project Purpose and Need Treated Water System Denver Water Customers Basis for Purpose and Need Existing and Future Demand Existing Use and Demand Forecast Conservation Natural Replacement Intergovernmental Agreement with Arvada Strategic Water Reserve Demand Summary Yield of Denver Water s System PACSM Modeling Overview Denver Water s Near-Term Strategy (Present to 2030) Conservation Non-Potable Recycling System Refinements Cooperative Projects Summary of Near-Term Strategy Timeliness and Location of New Yield Raw Water Availability to the Moffat Treatment Plant (System Reliability) Master TOC i

7 MASTER TABLE OF CONTENTS System Vulnerability Operational Flexibility Summary Required Permits and Approvals Public Scoping and Issues Chapter 2 Proposed Action and Alternatives Introduction Preliminary Alternatives Screening Process Screen 1A Long List of Water Supply Sources and Components Screen 1B Screen 1C Screen Refinement of EIS Alternatives Overview of Alternatives Proposed Action Gross Reservoir Expansion (72,000 AF) Introduction/Abstract Project Components Gross Reservoir Proposed Changes to Denver Water s System Operations Alternative 1c Gross Reservoir Expansion (40,700 AF)/New Leyden Gulch Reservoir (31,300 AF) Introduction/Abstract Project Components Gross Reservoir Proposed Leyden Gulch Reservoir Proposed Changes to Denver Water s System Operations Alternative 8a Gross Reservoir Expansion (52,000 AF)/Reusable Return Flows/Gravel Pit Storage (5,000 AF) Introduction/Abstract Project Components Gross Reservoir Proposed Gravel Pit Storage Facilities Proposed Changes to Denver Water s System Operations Alternative 10a Gross Reservoir Expansion (52,000 AF)/Reusable Return Flows/Denver Basin Aquifer Storage (20,000 AF) Introduction/Abstract Project Components Gross Reservoir Proposed Aquifer Storage and Recovery System Proposed Changes to Denver Water s System Operations ii Master TOC

8 MASTER TABLE OF CONTENTS Volume 2 of Alternative 13a Gross Reservoir Expansion (60,000 AF)/Transfer of Agricultural Water Rights/Gravel Pit Storage (3,625 AF) Introduction/Abstract Project Components Gross Reservoir Proposed Gravel Pit Storage Facilities Proposed Changes to Denver Water s System Operations Construction Activities for All Action Alternatives Schedule and Sequencing Temporary Sediment and Erosion Control Pipeline Construction Methods Construction Equipment Construction Traffic Construction Manpower Estimate Post-Construction Activities for All Action Alternatives Estimated Cost of Alternatives Action Alternatives No Action Alternative No Action Alternative Introduction/Abstract Project Components Strategic Water Reserve Strategy Mandatory Restrictions Strategy Definition of No Action Alternative Implications of the No Action Alternative Susceptibility to Unforeseen Challenges to the Water Supply System Raw Water Shortages Unmet Treated Water Demands Increased Treatment Plant Vulnerability Drawdown of Gross Reservoir Comparison of Alternatives Comparison of Alternative Elements Comparison of Impacts Chapter 3 Affected Environment Introduction Surface Water Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Master TOC iii

9 MASTER TABLE OF CONTENTS iv Master TOC Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities River Segments Fraser River Williams Fork River Colorado River Blue River South Boulder Creek North Fork South Platte River South Platte River Channel Dynamics Fraser River Williams Fork River Colorado River Blue River South Boulder Creek North Fork South Platte River South Platte River Groundwater Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems South Platte River Facilities Denver Basin Aquifer Facilities River Segments Fraser River Williams Fork River Upper Colorado River Blue River South Boulder Creek North Fork South Platte River and Mainstem South Platte River Geology Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O

10 MASTER TABLE OF CONTENTS South Platte River Facilities Denver Basin Aquifer Facilities Soils Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities Vegetation Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities Riparian and Wetland Areas Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities River Segments Fraser River Williams Fork River Colorado River Blue River South Boulder Creek North Fork South Platte River South Platte River Wildlife Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Master TOC v

11 MASTER TABLE OF CONTENTS Conveyance Systems Conduit M Conduit O South Platte River Facilities Gravel Pits Denver Basin Aquifer Facilities River Segments Fraser River Williams Fork River Colorado River Blue River South Boulder Creek North Fork South Platte River South Platte River Special Status Species Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities River Segments Fraser River Williams Fork River Colorado River Blue River South Boulder Creek North Fork South Platte River South Platte River Downstreaem Colorado River Platte River (Central Nebraska) Aquatic Biological Resources Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities vi Master TOC

12 MASTER TABLE OF CONTENTS River Segments Fraser River Williams Fork River Colorado River Blue River South Boulder Creek North Fork South Platte River South Platte River Transportation Overview Reservoirs Gross Reservoir Proposed Leyden Gulch Reservoir Site Conveyance Systems South Platte River Facilities Denver Basin Aquifer Facilities Air Quality Overview National Ambient Air Quality Standards Regional Haze/Visibility/Extinction Status of State Implementation Plans Air Quality Conformity Noise Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems South Platte River Facilities Denver Basin Aquifer Facilities Recreation Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Storage Denver Basin Aquifer Facilities River Segments Fraser River Williams Fork River Colorado River Master TOC vii

13 MASTER TABLE OF CONTENTS Blue River South Boulder Creek North Fork South Platte River South Platte River Land Use Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities Visual Resources Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities River Segments Cultural Resources/Paleontology Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O South Platte River Facilities Denver Basin Aquifer Facilities Socioeconomics Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site Conveyance Systems Conduit M Conduit O viii Master TOC

14 MASTER TABLE OF CONTENTS Volume 3 of South Platte River Facilities South Platte River Facilities Water Rights Acquisition Area Denver Basin Aquifer Facilities Denver Basin Aquifer Facilities PIA Advanced Water Treatment Plant Secondary Impact Areas Adams County Boulder County City of Brighton Denver County Denver Metroopolitan Area Grand County Jefferson County Weld County Hazardous Materials Overview Reservoirs Gross Reservoir Leyden Gulch Reservoir Site South Platte River Facilities Chapter 4 Environmental Consequences Introduction Surface Water Proposed Action (Alternative 1a) Reservoir Evaporation, Fluctuation, and Quality River Segments Alternative 1c Reservoir Evaporation, Fluctuation, and Quality River Segments Alternative 8a Reservoir Evaporation, Fluctuation, and Quality River Segments Alternative 10a Reservoirs and River Segments Alternative 13a Reservoir Evaporation, Fluctuation, and Quality River Segments No Action Alternative Depletion of Strategic Water Reserve Strategy Reservoir Evaporation, Fluctuation, and Quality Master TOC ix

15 MASTER TABLE OF CONTENTS River Segments Combination Strategy Mitigation and Monitoring Unavoidable Adverse Impacts Groundwater Proposed Action (Alternative 1a) Gross Reservoir River Segments Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Geology Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M x Master TOC

16 MASTER TABLE OF CONTENTS Alternative 13a Gross Reservoir South Platte River Facilities Conduit O No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Soils Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M Alternative 13a Gross Reservoir South Platte River Facilities Conduit O No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Vegetation Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M Alternative 13a Gross Reservoir Master TOC xi

17 MASTER TABLE OF CONTENTS South Platte River Facilities Conduit O No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Riparian and Wetland Areas Proposed Action (Alternative 1a) Gross Reservoir River Segments Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Depletion of Strategic Water Reserve Strategy Combination Strategy Mitigation and Monitoring Compensatory Mitigation Mitigation During Construction Alternative 1c - Leyden Gulch Reservoir Site Unavoidable Adverse Impacts Wildlife Proposed Action (Alternative 1a) Gross Reservoir River Segments Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments xii Master TOC

18 MASTER TABLE OF CONTENTS Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Mitigation and Monitoring Gravel Pit Habitat Management Unavoidable Adverse Impacts Special Status Species Proposed Action (Alternative 1a) Gross Reservoir River Segments Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Master TOC xiii

19 MASTER TABLE OF CONTENTS xiv Master TOC 4.9 Aquatic Biological Resources Proposed Action (Alternative 1a) Gross Reservoir River Segments Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Depletion of Strategic Water Reserve Strategy Combination Strategy Mitigation and Monitoring Unavoidable Adverse Impacts Transportation Proposed Action (Alternative 1a) Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M Alternative 13a Gross Reservoir South Platte River Facilities Conduit O

20 MASTER TABLE OF CONTENTS No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Air Quality Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Alternative 13a Gross Reservoir South Platte River Facilities No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Noise Proposed Action (Alternative 1a) Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M Alternative 13a Gross Reservoir South Platte River Facilities Conduit O No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Recreation Proposed Action (Alternative 1a) Gross Reservoir River Segments Master TOC xv

21 MASTER TABLE OF CONTENTS xvi Master TOC Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Depletion of Strategic Water Reserve Strategy Combination Strategy Mitigation and Monitoring Unavoidable Adverse Impacts Land Use Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M Alternative 13a Gross Reservoir South Platte River Facilities Conduit O No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts

22 MASTER TABLE OF CONTENTS 4.15 Visual Resources Proposed Action (Alternative 1a) Gross Reservoir River Segments Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site River Segments Alternative 8a Gross Reservoir South Platte River Facilities Conduit O River Segments Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M River Segments Alternative 13a Gross Reservoir South Platte River Facilities Conduit O River Segments No Action Alternative Mitigation and Monitoring Unavoidable Adverse Impacts Cultural Resources/Paleontology Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Conduit O Alternative 10a Gross Reservoir Denver Basin Aquifer Facilities Conduit M Alternative 13a Gross Reservoir South Platte River Facilities Conduit O No Action Alternative Master TOC xvii

23 MASTER TABLE OF CONTENTS xviii Master TOC Mitigation and Monitoring Unavoidable Adverse Impacts Socioeconomics Alternative 1a (Proposed Action) Economic Conditions Demographic Conditions Environmental Justice Housing Conditions Fiscal Conditions of Public Entities other than Denver Water Public Facilities and Services Financial Impacts to Denver Water Customers Summary of Socioeconomic Impacts of the Proposed Action Alternative 1c Economic Conditions Demographic Conditions Environmental Justice Housing Conditions Fiscal Conditions of Public Entities other than Denver Water Public Facilities and Services Financial Impacts to Denver Water Customers Summary of Socioeconomic Impacts of Alternative 1c Alternative 8a Economic Conditions Demographic Conditions Environmental Justice Housing Conditions Fiscal Impacts of Public Entities other than Denver Water Public Facilities and Services Financial Impacts to Denver Water Customers Summary of Socioeconomic Impacts of Alternative 8a Alternative 10a Economic Conditions Demographic Conditions Environmental Justice Housing Conditions Fiscal Impacts of Public Entities other than Denver Water Public Facilities and Services Financial Impacts to Denver Water Customers

24 MASTER TABLE OF CONTENTS Summary of Socioeconomic Impacts of Alternative 10a Alternative 13a Economic Conditions Demographic Conditions Environmental Justice Housing Conditions Fiscal Impacts of Public Entities other than Denver Water Public Facilities and Services Financial Impacts to Denver Water Customers Summary of Socioeconomic Impacts of Alternative 13a No Action Alternative Vulnerability and Risk Raw Water Shortages Treated Water Shortages Drawdown of Gross Reservoir Financial Impacts to Denver Water Customers Summary of Socioeconomic Impacts of the No Action Alternative Comparison of Major Aspects of the Socioeconomic Analysis Hazardous Materials Proposed Action (Alternative 1a) Gross Reservoir Alternative 1c Gross Reservoir Leyden Gulch Reservoir Site Alternative 8a Gross Reservoir South Platte River Facilities Alternative 10a Gross Reservoir Alternative 13a Gross Reservoir South Platte River Facilities No Action Alternative Mitigation and Monitoring Avoidance, Minimization and Mitigations Measures by Alternative Unavoidable and Adverse Impacts Irreversible or Irretrievable Commitment of Resources Comparison of Alternatives Master TOC xix

25 MASTER TABLE OF CONTENTS Chapter 5 Cumulative Effects Introduction Justification and Methodology for Cumulative Effects Analysis Past Actions Past Water-Based Actions Past Land-Based Actions Reasonably Foreseeable Future Actions Future Water-Based Actions Future Land-Based Actions Climate Change and Water Resources Relation of Rising Temperature and Water Resources in the West Climate Change and Water Managers Actions Not Considered Reasonably Foreseeable Water-Based Actions Land-Based Actions Evaluation of Cumulative Effects Surface Water Groundwater Geology Soils Vegetation Riparian and Wetland Areas Wildlife Special Status Species Aquatic Resources Transportation Air Quality Noise Recreation Land Use Visual Resources Cultural Resources/Paleontology Socioeconomics Hazardous Materials Summary of Cumulative Effects Chapter 6 Consultation and Coordination Public Participation Summary Public Scoping Consultation List of Reviewers and Preparers xx Master TOC

26 MASTER TABLE OF CONTENTS List of Tables Table 1-1 Summary of Denver Water s Planning Estimates Table 1-2 Summary of Conservation Measures ( ) Table 1-3 Yield of Denver Water s System Table 1-4 Representative System Refinement Projects Table 1-5 Environmental Permits and Approvals Likely Required to Construct and Operate the Moffat Collection System Project Table 2-1 Screen 1A Criteria Table 2-2 Description of Water Supply Sources and Infrastructure Components in the Long List Table 2-3 Screen 1A Summary Table 2-4 Project Alternatives Evaluated in Screen 1B Table 2-5 Relative Cost of Project Alternatives Table 2-6 List of Alternatives Evaluated in Screen 2 Table 2-7 Screen 2 Comparative Ranking Summary Table 2-8 List of EIS Alternatives Table 2-9 Denver Water s Estimated Unused Reusable Water Table 2-10 Proposed Action (Alternative 1a) Primary Components Table 2-11 Comparisons of Gross Dam and Reservoir Features by Alternative Table 2-12 Alternative 1c Primary Components Table 2-13 Alternative 8a Primary Components Table 2-14 Alternative 10a Primary Components Table 2-15 Alternative 13a Primary Components Table 2-16 Estimated Construction Schedules by Alternative Table 2-17 Typical Construction Sequences Table 2-18 Estimated On-Site Construction Equipment Table 2-19 Estimated One Way Vehicle Trips Table 2-20 Construction Manpower Estimate (Full-time Equivalent Workers) Table 2-21 Summary of Estimated Costs of Each Action Alternative Table 2-22 Summary of Monthly Drought Restrictions (2002 through 2005) Table 2-23 Summary of Monthly Water Demand Reductions (2002 through 2005) Master TOC xxi

27 MASTER TABLE OF CONTENTS Table 2-24 Table 2-25 Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Summary of Denver Water s Supply and Demand Summary of Major Characteristics and Impacts of Alternatives River Segments Study Areas Denver Water Gross Reservoir Storage Rights Conduit M Stream Crossings Conduit O Stream Crossings Gravel Pit Pipeline Stream Crossings Denver Basin Aquifer ASR Pipeline Stream Crossings Moffat Collection System Diversion Points Denver Water Fraser River Basin Water Rights at Existing Structures Moffat Collection System Minimum Bypass Requirements Colorado Water Conservation Board Minimum Instream Flow Rights below Moffat Collection System Summary of Average Annual Stream Flow and Depletions for the Fraser River near Winter Park Gage for the Period from 1975 through 2004 Designated Use Classification of River Segments Denver Water Williams Fork Basin Water Rights at Existing Structures Colorado Water Conservation Board Minimum Instream Flow Rights below Williams Fork Collection System Summary of Average Annual Stream Flow and Depletions for the Colorado River at Windy Gap Gage for the Period from 1985 through 2004 Denver Water Blue River Basin Water Rights at Existing Structures Colorado Water Conservation Board Minimum Instream Flow Rights on Blue River below Dillon Reservoir Denver Water South Boulder Creek Basin Water Rights at Existing Structures Stream Channel Characteristics of the Focus River Segments Attributes of Representative Sampling Sites Water Budget for Fraser River Watershed under Current Conditions Water Budget for Williams Fork River Sub-Watershed (above Leal gage) under Current Conditions Water Budget for Blue River Sub-Watershed (between Dillon and Green Mountain Reservoirs) under Current Conditions Noxious Weeds Observed or Expected to be Present in the Project Area xxii Master TOC

28 MASTER TABLE OF CONTENTS Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Summary of Riparian Areas and Wetlands in the Moffat Collection System East Slope Project Study Areas Summary of Other Water Features Within the Front Range Facilities Study Areas Summary of Riparian Areas and Wetlands in the Gross Reservoir Study Area Summary of Riparian Areas and Wetlands in the Leyden Gulch Study Area Summary of Riparian Areas and Wetlands Associated with South Platte River Facilities Summary of Riparian Areas and Wetlands along the Denver Basin Aquifer Facilities Distribution Pipeline Acreage of CDOW Riparian Vegetation Types Along the Focus River Segments Acreage of CNHP Groups/Plant Associations: Sampling Sites FR1, FR3, and FR4 on the Upper Reach of the Fraser River Acreage of CNHP Groups/Plant Associations: Sampling Site FR2 on the Fraser Canyon Reach of the Fraser River Acreage of CNHP Groups/Plant Associations: Sampling Site WF1 on the Williams Fork River Acreage of CNHP Groups/Plant Associations: Sampling Site WF2 on the Williams Fork River Acreage of CNHP Groups/Plant Associations: Sampling Site CR1 on the Colorado River Acreage of CNHP Groups/Plant Associations: Sampling Site BR1B on the Blue River Acreage of CNHP Groups/Plant Associations: Sampling Site SBC1C on South Boulder Creek Acreage of CNHP Groups/Plant Associations: Sampling Site SBC3B on South Boulder Creek Acreage of CNHP Groups/Plant Associations: Sampling Site NF1D on the North Fork South Platte River Acreage of CNHP Groups/Plant Associations: Sampling Site NF2F on the North Fork Raptors Likely or Known to Occur in the Gross Reservoir Study Area Common Songbirds in the Gross Reservoir Study Area by Habitat Type Management Indicator Species for the Arapaho & Roosevelt National Forest Birds Observed or Likely Present in the Leyden Gulch Site Master TOC xxiii

29 MASTER TABLE OF CONTENTS Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Common Wildlife Species that Occur in the Conveyance System Study Areas Waterfowl and Shorebirds Dependent on South Platte River Corridor during Winter or Migration Bird Species Breeding in Riparian and Wetland Habitats along the River Segments Mammal Species Likely or Known to Occur in Riparian and Wetland Habitats along the River Segments Fish Species Collected in the Moffat Collection System Project Area Invertebrate Classes/Orders Collected in the Moffat Collection System Project Area Gross Reservoir, Fish Population Data, Percent (%) of Total Catch, 1970 to 1996 Study Area Streams and Stream Segments Fraser River Mainstem, Downstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1985 to 2007 Fraser River Tributary Streams, Data Availability in Focus Reaches Upstream and Downstream of Existing Denver Water Diversions St. Louis Creek, Downstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1993 to 2003 Vasquez Creek, Downstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1984 and 1993 Jim Creek, Downstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1993 and 2005 Main Ranch Creek, Downstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1993 and 2005 South Fork Ranch Creek, Upstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 2003 Meadow Creek, Downstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1993 and 2005 Fraser River Tributary Streams, Benthic Macroinvertebrate Population Parameters Downstream of Denver Water Diversions, 2005 Bobtail Creek, Upstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1984 to 2003 Steelman Creek, Upstream of Denver Water Diversion, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1984 to 2004 xxiv Master TOC

30 MASTER TABLE OF CONTENTS Table Williams Fork River Tributary Streams, Benthic Macroinvertebrate Population Parameters Downstream of Denver Water Diversions, 1984 Table Blue River: Dillon Reservoir to Green Mountain Reservoir, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1976 to 2000 Table Blue River: Dillon Reservoir to Green Mountain Reservoir, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 2001 to 2005 Table South Boulder Creek: Upstream of Gross Reservoir, Fish Population Data, Percent (%) of Total Catch, 1963 to 1991 Table South Boulder Creek, Benthic Macroinvertebrate Data, 1984 and 1985 Table South Boulder Creek: Downstream of Gross Reservoir, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1976 to 1996 Table North Fork South Platte River, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1976 to 2004 Table South Platte River: Chatfield Reservoir to Bear Creek, Fish Population Data, Percent (%) of Total Catch, and Summary Parameters, 1979 to 2003 Table South Platte River: Chatfield Reservoir to Bear Creek, Fish Population Data, Percent (%) of Total Catch, by Habitat in Warm and Coldwater Sections, 2005 Table Transportation Network Improvements Table Average Maximum and Minimum Temperatures ( F) Table Average Total Precipitation and Snowfall (inches) Table Wind Data Table National Ambient Air Quality Standards Table National Ambient Air Quality Standard Monitoring Data Table Colorado Class I Areas Table Average Visibility for Table Mean Visibility Data for 2004 Table Visibility Trends in Denver and the Front Range for 1990 through 2005 Table NAAQS Non-attainment and Maintenance Areas in the Denver Area Table Conformity de Minimus Threshold Levels Table CDOT Noise Abatement Criteria A-Weighted Sound Level-Decibels (dba) Table a Allowable Noise Levels (dba) - Adams County Table b Allowable Noise Levels (dba) - Boulder County Table c Allowable Noise Levels (dba) - City and County of Denver Table d Allowable Noise Levels (dba) - Jefferson County Master TOC xxv

31 MASTER TABLE OF CONTENTS Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Existing and Planned Recreation Facilities at Gross Reservoir Previously Recorded Sites in the Gross Reservoir APE Newly Recorded Sites in the Gross Reservoir APE Previously Recorded Sites in the Leyden Gulch Site APE Newly Recorded Sites in the Leyden Gulch Site APE Previously Recorded Sites within the Conduit M APE Previously Recorded Sites within the Conduit O APE Previously Recorded Sites in the South Platte River Facilities APE Sites Recorded in the Denver Basin Aquifer Storage and Recovery APE Socioeconomic Primary and Secondary Impact Areas for Each Project Component and Alternative Hazardous Material Site Database Search Criteria Hazardous Material Sites Identified Within the Gross Reservoir Study Area in 2006 Hazardous Material Sites Identified Adjacent to and Within the Leyden Gulch Site in 2006 Hazardous Material Sites Identified Near the Worthing, South Tower, and Challenger Gravel Pits in 2006 Sediment Supply Equations Locations where Hydrologic Data were Analyzed in the Fraser River Basin Wastewater Treatment Facilities in Fraser River Watershed Wastewater Treatment Plant Effluent in Fraser River Basin Impact of Lower Flows on Percentage of Stream that is Wastewater Effluent for Winter Park Water and Sanitation District Impact of Lower Flows on Percentage of Stream that is Wastewater Effluent for Fraser Sanitation District Impact of Lower Flows on Percentage of Stream that is Wastewater Effluent for the Granby Wastewater Treatment Facility Water Quality Data for Vasquez Creek for Parameters with CDPHE Stream Standards Water Quality Data for Vasquez Creek for Parameters not listed in Table that have Drinking Water Standards Water Quality Data for Vasquez Creek for Parameters without Stream Standards or Drinking Water Standards xxvi Master TOC