Pre- and post-construction water quality monitoring for HREP Belanger, K. D., D. J. Dieterman, and T. W. Deyo. 1990. Pre- and post-construction water quality monitoring for Habitat Rehabilitation and Evaluation Projects at Big Lake Bay, Finger Lakes, Lake Onalaska, and the Pool 8 islands area of the Upper Mississippi River. U.S. Fish and Wildlife Service, Environmental Management Technical Center, Onalaska, Wisconsin, September 1990. EMTC 90-04. 17 pp. (NTIS # PB91-106385) ABSTRACT Continuous dissolved oxygen and temperature readings were taken along with early morning readings in Big Lake Bay, Finger Lakes, and the Pool 8 Islands area to document and provide preproject data on each location. Similar readings were taken in Lake Onalaska to provide postproject data. Sampling took place from August 13 through September 5, 1990. All sites displayed daily fluctuations in dissolved oxygen and water temperature. Daily variation in dissolved oxygen and temperature relate directly to the daily weather conditions. Overcast, cloudy days have less fluctuation in dissolved oxygen and temperature than do sunny days. Density of aquatic vegetation and lake size also influenced the extent of variability in dissolved oxygen, with sites having a large surface area and low plant density showing more stability than sites of small area and high macrophyte density. This is presumably due to the effects of mixing and photosynthetic activity. KEYWORDS habitat project, preproject, water quality, aquatic vegetation