Precipitation and streamwater chemistry in an undisturbed watershed in southeast Alaska.

Abstract

Water chemistry samples have been taken from streamflow since 1976 and precipitation since 1978 in Indian River, an undisturbed watershed on Chichagof Island in Southeast Alaska. Volume weighted concentrations of total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, orthophosphate, sulfate sulfur, chloride, bicarbonate, silica, calcium, magnesium, sodium, and potassium were used with precipitation and streamflow volumes to calculate annual input and output of elements. Total nitrogen accumulated at 1.0 kg/ha per year and ammonium-nitrogen at 3.3 kg/ha per year; other monitored elements showed a net loss or export from 0.1 kg/ha per year of total phosphorus to 256 kg/ha per year of calcium. Precipitation and weathering of soil and bedrock material account for these elemental losses in streamflow. The geochemistry of Indian River is compared to other studies done in mountainous forested watersheds.

Citation

Stednick, John D. 1981. Precipitation and streamwater chemistry in an undisturbed watershed in southeast Alaska. Res. Pap. PNW-RP-291. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 8 p