WRIA 30 - Klickitat County Home

Klickitat River BasinWatershed Management Plan2.0 EXISTING CONDITIONSThis section summarizes existing conditions in WRIA 30, including water rights, use, allocation,and demand; surface and ground water resources; surface and ground water quality, and fishhabitat. This section provides basic background information summarized from the WRIA 30Watershed Assessment (Watershed Professionals Network (WPN) and Aspect, 2005). Thereader is referred to the WRIA 30 Watershed Assessment for more detailed informationregarding the subjects covered in this section, including references and citations supporting theinformation and methods used to develop the assessment.2.1 PHYSICAL SETTINGWRIA 30 is located in Klickitat and Yakima Counties in south central Washington. The primaryrivers in the WRIA are the Klickitat River and the Columbia River. The headwaters of theKlickitat River drain from Mount Adams and the eastern flanks of the Cascade Mountains. Theprimary tributary to the lower Klickitat River is the Little Klickitat River, which drains theSimcoe Mountains located to the east of the mainstem Klickitat River.For the purposes of the watershed assessment, WRIA 30 was subdivided into six subbasins(Figure 2). These include the Upper Klickitat, the Middle Klickitat, the Lower Klickitat, theLittle Klickitat, Swale, and Columbia Tributaries Subbasins. Most of the subbasins incorporateone or more major tributaries as well as some of the smaller side tributaries that drain to theKlickitat River; however, the subbasin designated as “Columbia Tributaries” encompassesseveral very small tributaries, all of which drain directly to the Columbia River. Most of theUpper Subbasin and the eastern half of the Middle Klickitat Subbasin are within the YakamaIndian Reservation, which were nominally addressed in the assessment.Elevation in the WRIA ranges from 75 feet at the Columbia River to 12,296 feet at the crest ofMount Adams (Table 1). The Upper Klickitat Subbasin contains many areas of high topographicrelief, particularly near Mt. Adams. Many of the headwater areas of the Little Klickitat River arealso relatively steep. The remainder of WRIA 30 consists primarily of low rolling hills with theexception of areas where water features have dissected the underlying bedrock creating steepcanyon areas. Such canyons can be found in the lower reaches of the Little Klickitat River, thelower Klickitat River Subbasin, the lower portion of Swale Creek, near the mouths of most of thetributaries to the Klickitat and Little Klickitat Rivers, and in the smaller tributaries along theColumbia River.Precipitation is highly variable in the WRIA. Mean annual precipitation generally increases withelevation and from east to west. Mean annual precipitation is as little as nine inches per year inthe eastern end of the Columbia Tributaries Subbasin and as high as 105 inches per year onMount Adams in the Upper Klickitat Subbasin (Figure 3).Existing Conditions 11 May 3, 2005