Nutrient Transport in Surface Runoff from a Subalpine Watershed, Lake Tahoe Basin, California

作者：Robert L. Leonard, Louis A. Kaplan, John F. Elder, Robert N. Coats, Charles R. Goldman · 发表于：Ecological Monographs · 年份：1979 · DOI：10.2307/1942486 · 被引用次数：65 · 研究领域：Soil and Water Nutrient Dynamics、Hydrology and Watershed Management Studies、Aquatic Ecosystems and Phytoplankton Dynamics

The watershed of Ward Creek, a tributary to oligotrophic Lake Tahoe in the Sierra Nevada, has been investigated since 1971 with the objective of improving our knowledge of processes of nutrient and sediment release and transport to the lake. Quantitative data on selected stream water parameters were collected for 3 yr (1972—1975) at three stations on Ward Creek, two on the main upper tributaries and one near the stream mouth. Comparative data were collected at a stream mouth station on adjacent Blackwood Creek in the 3rd yr. The parameters were selected on the basis of their significance to eutrophication of Lake Tahoe. Precipitation in a normal year is over 90% snow but annual patterns vary widely and rainfall at any time of year can be highly important in sediment and nutrient transport. Water discharge and the flux of suspended sediments, NO3—N, phosphorus, iron and trace metals were dominated by the spring snowmelt runoff from mid—April to mid—June. However, in 1974 heavy fall and summer rains accounted for a large percentage of the annual flux of sediments and nutrients in a total of only 14 d. The spring runoff was characterized by distinct diel water discharge patterns. Similar but not coincident patterns were found to exist for sediments and nutrients, including NO3—N, but not for soluble phosphorus. The Ward watershed has 87% the area of Blackwood but discharge proportionately much lower quantities of sediment and nutrients in comparable water yields per hectare in w...