WATER QUALITY AND PHYTOPLANKTON COMMUNITY COMPOSITION IN A SOURCE WATER RESERVOIR, LAKE HOUSTON NEAR HOUSTON, TEXAS, APRIL 2006— SEPTEMBER 2008

Lake Houston, a shallow, turbid reservoir, is currently (2010) a primary surface-water source of drinking water for the city of Houston, Texas and surrounding areas. The U.S. Geological Survey, in cooperation with the City of Houston, established a water-quality monitoring network to track daily changes in water quality. Continuous and discrete water-quality data were collected 2006—2008 at multiple locations to characterize the in-lake processes that affect water quality. Physiochemical water-quality properties (water temperature, pH, specific conductance, dissolved oxygen concentration, and turbidity) were monitored hourly from mobile, multi-depth monitoring stations developed and constructed by the USGS at five locations on the lake. Discrete water samples were collected routinely at the continuous monitoring stations and analyzed for various water-quality properties and constituents. Properties and constituents include: nutrients, acid neutralizing capacity, fecal indicator bacteria, suspended sediment and loss on ignition, phytoplankton (abundance, biovolume and community composition), taste-and-odor causing compounds (geosmin, 2-methylisoborneol), cyanobacterial toxins (microcystin), actinomycetes bacteria, and field measurements of physiochemical properties. In addition to the routinely sampled compounds, synoptic samples also were collected and analyzed for major ions and trace metals, wastewater indicators, pesticides, and volatile organic compounds. Results and analyses to date will be presented.