Comparison of water quality for upstream and downstream sites in the Incline Creek Watershed, Lake Tahoe Basin, Nevada, 1990-98

TitleComparison of water quality for upstream and downstream sites in the Incline Creek Watershed, Lake Tahoe Basin, Nevada, 1990-98
Publication TypeConference Proceedings
Year of Conference1999
AuthorsRowe, T. G.
Conference Name67th Annual Western Snow Conference
Series TitleProceedings of the 67th Annual Western Snow Conference
Date PublishedApril 1999
PublisherWestern Snow Conference
Conference LocationSouth Lake Tahoe, California
KeywordsMonitoring network, Nutrients, Sediments, Water quality
Abstract

The U.S. Geological Survey, and the Tahoe Research Group, in cooperation with the Tahoe Regional Planning Agency, has monitored tributaries in the Lake Tahoe Basin since 1987. Monitoring is to determine streamflow and concentrations of sediment and nutrients to Lake Tahoe. In 1989, the monitoring network was expanded to support the assessment of the effects of land use and development on water quality in the basin. Data from one watershed, Incline Creek, are described for the 1990-98 water years.The median values of instantaneous streamflow, specific conductance, suspended sediment, and bioreactive iron all increased in a downstream direction. Median streamflow increased from 3.1 to 8.2 ft3/S (cubic feet per second) and median specific conductance increased from 35 to 78 uS/cm (microsiemens per centimeter) at 25deg C (degrees Celsius). Also in a downstream direction, median suspended sediment increased from 7 to 24 mg/L (milligrams per liter) and median bioreactive iron increased from 242 to 972 ug/L (micrograms per liter).The median values of total Kjeldahl nitrogen and total phosphorus increased slightly in a downstream direction. Median total KjeldahI nitrogen increased from 0.160 to 0.206 mg/L and median total phosphorus from 0.036 to 0.055 mg/L. The median values of water temperature, pH, and concentrations of dissolved oxygen, dissolved nitrite plus nitrate, dissolved ammonia, and dissolved orthophosphorus showed virtually no trends with distance downstream.

URLsites/westernsnowconference.org/PDFs/1999Rowe.pdf