Changes in water quality and climate after forest harvest in central Washington state.

Abstract

Chemical output of nitrate, calcium, magnesium, sodium, potassium, and organic nitrogen were determined on a grams-per-hectare-per-day basis for five treatment watersheds and a control watershed. Water samples were collected from April to October during 3 pretreatment and 3 posttreatment years (1978 to 1983). Except for increased calcium and sodium in several streams, regression equations comparing treatment with control showed no significant difference for pretreatment and posttreatment output. Output generally declined in the posttreatment years. Cyclic changes in output from these and other streams in the eastern Cascade Range in Washington appeared to occur regardless of treatment and were probably related to precipitation. Mean maximum air temperature increased during the posttreatment period in all the small watersheds, but stream temperatures were relatively unaffected.

Citation

Fowler, W.B.; Anderson, T.D.; Helvey, J.D. 1988. Changes in water quality and climate after forest harvest in central Washington state. Res. Pap. PNW-RP-388. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p