05/25/04 The Dalles Watershed Assessment The Dalles Watershed Assessment Prepared by Wasco County Soil and Water Conservation District For The Dalles Watershed Council Principal Author: Kim Guess Northwest Service Academy Trout Lake, WA Editor: Jennifer Shannon Clark, Wasco County Soil and Water Conservation District The Dalles, OR As accepted by watershed council action January 2003 0 05/25/04 The Dalles Watershed Assessment 1 05/25/04 The Dalles Watershed Assessment Table of Contents List of Tables and Charts .................................................................................................3 List of Maps .....................................................................................................................3 Introduction....................................................................................................................4 Preparation .....................................................................................................................4 1) Description of The Dalles Watershed ......................................................................5 Geology........................................................................................................................5 Ecoregions....................................................................................................................5 2) Climate........................................................................................................................5 3) History ........................................................................................................................5 Historical Timeline.......................................................................................................5 Historic Forest Composition ........................................................................................5 Fire History ..................................................................................................................5 5) Channel Habitat Type Classification.......................................................................5 6) Hydrology and Water Use.........................................................................................5 Runoff versus Infiltration.............................................................................................5 Effects of Land Use on Runoff ....................................................................................5 Effects of Roads on Runoff..........................................................................................5 Streamflow Characteristics ..........................................................................................5 7) Riparian and Wetlands Conditions..........................................................................5 Riparian Conditions .....................................................................................................5 Wetlands.......................................................................................................................5 8) Sediment Sources .......................................................................................................5 Cropland sediments......................................................................................................5 Road sediments ............................................................................................................5 9) Channel Modification................................................................................................5 10) Water Quality...........................................................................................................5 Temperature .................................................................................................................5 Turbidity.......................................................................................................................5 Pesticides......................................................................................................................5 11) Fish and Fish Habitat ..............................................................................................5 12) Watershed Condition Evaluation...........................................................................5 References .......................................................................................................................5 2 05/25/04 The Dalles Watershed Assessment List of Tables and Charts Table 1.1: Land Use in The Dalles Watershed (based on Wasco County Zoning Info)................................................5 Table 1.2: Ecoregions in The Dalles Watershed. Source: Oregon Natural Heritage Foundation (http://www.gis.state.or.us/data/alphalist.html) ....................................................................................................5 Table 5.1: Descriptions of channel habitat types found in The Dalles Watershed ........................................................5 Table 5.2: Summary (in miles) of channel habitat types for stream channels in The Dalles Watershed. Channel habitat types listed in order of frequency. .............................................................................................................5 Table 6.1: Cover Types by Subwatershed ........................................................................................................................5 Table 6.2: Average depth of 2-year, 24-hour runoff events and change from 1850 to 1990s in inches........................5 Table 6.3: Urban roads in The Dalles Subwatersheds.....................................................................................................5 Table 6.4: Road Densities in Non-Urban Land Use Zones..............................................................................................5 Chart 6.1: Streamflow and turbidity data collected at Wicks Water Treatment Plant on the S. Fork Mill Creek (1996-2001). ..............................................................................................................................................................5 Chart 6.2: Streamflow recorded by USGS at gage 14105600 (T1N R13E section 31) in Threemile Creek.................5 Chart 6.3: Natural flows of The Dalles Watershed streams. Source: Hydrologic Modeling, Water Resources Department...............................................................................................................................................................5 Chart 6.4: Expected flows in the streams after consumptive use. Source: Oregon Water Resources Department...5 Table 9.1: Modified Channels (in miles) by Subwatershed. Source: Aerial Photos, 1995. ..........................................5 Table 10.1: Water Quality Limited Streams in The Dalles Watershed (DEQ draft 303(d) list, 2002) ........................5 Table 10.2: Temperature Monitoring Locations in The Dalles Watershed ...................................................................5 Chart 10.1: Stream temperatures in Threemile Creek. Source: DEQ and SWCD. .....................................................5 Chart 10.2: Stream temperatures in Mill Creek. Source: DEQ, MHNF and SWCD. ..................................................5 Chart 10.3: Stream temperature in Chenowith Creek: Source: DEQ ...........................................................................5 Table 13-1. Major issues identified by watershed assessment and potential responses. ...............................................5 Table 13-2. Data Gaps and Recommended Further Studies...........................................................................................5 List of Maps Map 1.1: Location of The Dalles Watershed in the State of Oregon...........................................................5 Map 1.2: Land Use in The Dalles Watershed. Source: Wasco County Planning Dept.............................5 Map 1.3: Rowena Subwatershed ....................................................................................................................5 Map 1.4: Chenowith Subwatershed ...............................................................................................................5 Map 1.5: Mill Creek Subwatershed................................................................................................................5 Map 1.6: Dry Hollow Subwatershed ..............................................................................................................5 Map 1.7: Threemile Subwatershed.................................................................................................................5 Map 1.8: Ecoregions in The Dalles Watershed. Source: Oregon Natural Heritage Foundation (http://www.gis.state.or.us/data/alphalist.html)...................................................................................5 Map 2.1: Precipitation. Source: USDA climatological model and Hood River County Dept. of Forestry, verified with local data from Crow Creek Reservoir ..........................................................................5 Map 3.1: Forest Composition, 1855-1890. Source Public Land Survey Records .......................................5 Map 3.2: Fire Footprints and current vegetation. Sources: USFS and ODF records; see section 6 for current vegetation sources.....................................................................................................................5 Map 5.1: Channel Habitat Types. Source: 1995 Aerial Photos and Field Observation.............................5