Impact of Land Use and NPS Loads on Lake Quality

Abstract

Extensive land use, nonpoint source (NPS), and lake water quality data are used to determine the interaction of lake water quality and watershed development in the Lake Austin watershed. Historical trends in total suspended solids and total phosphorus are examined over the 1979–84 period, during which impervious cover increased by 79% in the lake watershed. A PC‐based continuous stirred tank reactor (CSTR) model is used to depict the response of lake water quality to loadings associated with a variety of development options ranging from impervious cover of 10–40%. The reliability of the model is supported by the unusually simple lake hydraulics, exclusive NPS loading, and extensive data base. Model results are used to create a set of recommendations that should protect the water quality of the lake.