Physical and Biological Characteristics
Hatwai Creek is 3 miles east of Lewiston, Idaho. Its watershed consists of 19,785 acres of cropland (56 percent), rangeland (31.5 percent), pasture/hayland (5 percent), riparian areas (2.5 percent), roads (2 percent), forestland (1 percent), mining (1 percent), and farms and suburban areas (1 percent). The watershed elevation ranges from 775 feet to 2,964 feet. Annual precipitation ranges from 10 inches at lower elevations to 22 inches at higher elevations. The watershed was listed on Idaho’s 303(d) list and also listed as critical habitat for steelhead salmon. The National Marine Fisheries Service (NMFS) listed steelhead as threatened in Hatwai Creek. The creek’s beneficial uses are agriculture water supply, secondary contact recreation, and salmonid spawning. The nonpoint source pollutants include sediment, nutrients, and high water temperature. The primary sources of such pollutants are nonirrigated cropland (headwater sites), rangeland (grazing activities), surface mining operations, and streambank erosion.
Studies, Plans and Reports
Hatwai Creek Subbasin Assessment TMDL (September 2010)
Lewiston Regional Office Department of Environmental Quality 1118 F. Street Lewiston, Idaho 83501
This subbasin assessment (SBA) and TMDL analysis have been developed to comply with
Idaho’s TMDL schedule. The assessment describes the physical, biological, and cultural setting;
water quality status; pollutant sources; and recent pollution control actions in the Hatwai Creek
subwatershed, located 3 miles east of Lewiston, Idaho
Hatwai Creek Riparian Demonstration and Erosion Control (Web Link)
Nez Perce Soil and Water Conservation District
Historical land use along Hatwai Creek included dairy and crop production and cattle feeding/finishing, which resulted in alteration of the natural stream channel and riparian area. Flood plain areas near the creek were leveled and sloped toward the creek for drainage; riparian vegetation was largely removed or heavily grazed; and the channel was straightened and its bottom flattened.