I-70 Mountain Corridor PEIS Water Resources Technical Report August 2010 Water Resources Technical Report This page intentionally left blank. Water Resources Technical Report Table of Contents I-70 Mountain Corridor PEIS Water Resources Technical Report..........................................1 Table of Contents.........................................................................................................................i List of Figures ............................................................................................................................iii List of Tables..............................................................................................................................iii Section 1. Purpose of the Report ..............................................................................................1 Section 2. Background and Methodology ................................................................................1 2.1 Major Water Resources Issues for the Corridor ..............................................................2 2.1.1 Highway Runoff and Winter Roadway Maintenance Activities ..............................2 2.1.2 Historic Mining .......................................................................................................4 2.1.3 Water Quality Impaired Streams, Stream Classifications, and Standards.............4 2.1.4 Spills and Hazardous Materials Transport.............................................................5 2.1.5 Development and Urbanization..............................................................................6 2.1.6 Channelization and Stream Flow...........................................................................7 2.2 Water Resources Regulations.........................................................................................8 2.2.1 Clean Water Act.....................................................................................................9 2.2.2 Water Quality Control Commission Standards ....................................................11 2.2.3 Potential Future Regulatory Requirements..........................................................12 2.3 Water Resources Planning and Projects.......................................................................12 2.3.1 Basin Specific Planning Projects .........................................................................12 2.3.2 TMDL Monitoring Results 1992 to 2006 – Straight Creek, Colorado, Final Report (Completed May 2007).................................................................15 2.3.3 Upper Clear Creek Watershed Plan (Completed February 2006) .......................16 2.3.4 Energy Development Water Needs Assessment, Phase I Report (Completed September 2008)...........................................................................16 2.3.5 Phase II Upper Colorado River Study, Final Report (Completed May 2003).......16 2.3.6 Water Availability Study of the Colorado River and Tributaries, Proposed August 2008......................................................................................................16 2.3.7 Memorandum of Agreement on Management of Mine-Related Materials in the Interstate 70 Mountain Corridor...............................................................17 2.4 Methodology ..................................................................................................................17 2.4.1 FHWA Stormwater Runoff Model.........................................................................17 2.4.2 BASINS Model.....................................................................................................22 Section 3. Description of Alternatives ....................................................................................24 3.1 Minimal Action Alternative .............................................................................................24 3.2 Transit Alternatives........................................................................................................24 3.2.1 Rail with Intermountain Connection .....................................................................24 3.2.2 Advanced Guideway System...............................................................................24 3.2.3 Dual-mode Bus in Guideway ...............................................................................24 3.2.4 Diesel Bus in Guideway.......................................................................................25 3.3 Highway Alternatives .....................................................................................................25 3.3.1 Six-Lane Highway 55 mph Alternative.................................................................25 3.3.2 Six-Lane Highway 65 mph Alternative.................................................................25 3.3.3 Reversible Lanes Alternative ...............................................................................25 3.4 Combination Alternatives...............................................................................................26 3.5 Preferred Alternative—Minimum and Maximum Programs ...........................................27 3.6 No Action Alternative .....................................................................................................27 Section 4. Affected Environment.............................................................................................27 4.1 Stream Morphology and Basin Characteristics..............................................................27 4.1.1 Colorado Headwaters Sub-Basin.........................................................................27 I-70 Mountain Corridor PEIS Technical Reports August 2010 Page i Water Resources Technical Report 4.1.2 Eagle River Sub-Basin.........................................................................................28 4.1.3 Blue River Sub-Basin...........................................................................................28 4.1.4 Clear Creek Sub-Basin ........................................................................................29 4.1.5 Upper South Platte River Sub-Basin....................................................................29 4.2 Water Use Information...................................................................................................30 4.2.1 Colorado Headwaters Sub-Basin.........................................................................30 4.2.2 Eagle River Sub-Basin.........................................................................................30 4.2.3 Blue River Sub-Basin...........................................................................................30 4.2.4 Clear Creek Sub-Basin ........................................................................................38 4.2.5 Upper South Platte River Sub-Basin....................................................................38 4.3 Stream Flow Information................................................................................................39 4.4 Winter Maintenance.......................................................................................................40 4.4.1 Summary of Maintenance Procedures.................................................................40 4.4.2 Winter Maintenance Material Usage....................................................................43 4.4.3 Highway Runoff and Water Quality......................................................................51 4.4.4 Environmental Effects of Deicers on Water Quality.............................................57 4.5 Water Quality Monitoring ...............................................................................................63 4.5.1 Colorado Headwaters Sub-Basin.........................................................................65 4.5.2 Eagle River Sub-Basin.........................................................................................65 4.5.3 Blue River Sub-Basin...........................................................................................69 4.5.4 Clear Creek Sub-Basin ........................................................................................73 4.5.5 Upper South Platte River Sub-Basin....................................................................77 Section 5. Environmental Consequences ..............................................................................78 5.1 Modeling Results ...........................................................................................................78 5.1.1 FHWA Stormwater Runoff Model Results............................................................78 5.1.2 BASINS Model Results........................................................................................80 5.2 Direct Impacts................................................................................................................91 5.2.1 Winter Maintenance Impacts to Water Quality.....................................................91 5.2.2 Highway Runoff ...................................................................................................92 5.2.3 Historic Mining .....................................................................................................95 5.2.4 Development and Urbanization............................................................................95 5.2.5 Channelization and Stream Flow.........................................................................95 5.3 Indirect Impacts .............................................................................................................97