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MICA CREEK, FISH CREEK, AND FREEMAN LAKE, IDAHO. STREAM AND LAKE NUTRIENT LOADING FROM BURNED LOGGING SLASH, BONNER AND KOOTENAI COUNTIES. 1989-1990
Description:
Three monitoring sites in Bonner and Kootenai Counties, Idaho (17010304) were chosen to give some insight into the question of nutrient contribution from logging slash. The sites were a Class II tributary to Mica Creek, a Class I tributary to Fish Creek, and a wet draw that flows into Freeman Lake. There was no attempt to quantify variables such as area of drainage, quantity of slash, slash distance to stream, length of burn, intensity of burn, soil permeability, slope, etc. The report gives the following general conclusions about slash burning in the stream protection zone. The first fall rains percolated into dry soil and carried much of the burned slash nutrients. Later fall rains carried nutrients to live streams. The first stream flows after slash burning had the highest nitrogen and phosphorus concentrations. Phosphorus and nitrogen concentrations returned to pre-burning levels after heavy winter rains. Nutrient concentrations associated with slash burning were approximately twice the concentrations before slash burning or after heavy winter rains. Phosphate concentrations in the Fish Creek tributary were 4 times higher than average Upper Twin Lake concentrations. With these concentrations entering the lake, the potential exists for stimulation of lake production (eutrophication). Skille, J. 1990. Water Quality Summary Report No. 26. Idaho Department of Health and Welfare, Division of Environmental Quality, Boise, ID. 14 pp.