Lake Water Quality

Green Lake is the deepest natural inland lake in Wisconsin. Through time its water quality has degraded, with relatively high phosphorus concentrations and zones of hypoxia. This project is quantifying the water quality of the lake and its tributaries, and it will provide information to help guide efforts to improve the lake.

The goals of this study were to quantify pathogen concentrations in water at three Lake Michigan beaches, identify environmental factors that influence pathogen occurrence and variability, and to estimate health risks for recreational swimmers.

Eutrophication of Delavan Lake accelerated from the 1940s to 1980s, resulting in a hypereutrophic lake with severe blue-green algae blooms. Extensive rehabilitation efforts were implemented to improve water quality. The USGS measured nutrients, suspended sediment, water quality, and plankton populations to quantify the effectiveness of rehabilitation efforts and guide future management decisions.

To reduce the impact of increasing urban development and recreational use on Geneva Lake, efforts are being made to decrease point- and nonpoint-source pollution inputs. To document Geneva Lake's water quality, the USGS collected water-quality data and developed empirical eutrophication models to demonstrate that reductions in phosphorus loading were related to water-quality improvements.

SPARROW models for the Mississippi/Atchafalaya River Basin(MARB) predict long-term average loads, concentrations, yields, and source contributions of water, nitrogen, phosphorus, and suspended sediment to the Gulf of Mexico.

SPARROW phosphorus and nitrogen models are being developed for the entire Great Lakes Basin and the Upper Midwest part of the U.S., and the Red and Assiniboine River Basin, as part of a Binational project between the USGS and the International Joint Commission (IJC) and National Research Council (NRC) of Canada.

To better understand the quality of water flowing into the Great Lakes, the USGS is conducting water-quality analyses for nutrients, sediment, and toxic substances and estimating the amount (load) of these substances for tributaries to the Great Lakes. Information on the occurrence and distribution of contaminants is needed to provide baseline information, measure progress towards restoration...

Recently, elevated chlorophyll-a concentrations were found related to persistent algal blooms on Silver Lake in Oceana County, MI. Elevated chlorophyll-a concentrations, high phosphorus concentrations during summer months, as well as a decrease in water clarity indicated potential accelerated eutrophication processes during the last two years, and underscore a need to characterize water and...

The Winnebago Pool Lakes are shallow, productive drainage lakes that have accumulated nutrients from its mixed agricultural/forest watershed and from the Fox River. High phosphorus concentrations often result in severe blue-green algae blooms that can produce harmful toxins. The USGS is evaluating the water quality and phosphorus budget of each lake and modeling eutrophication responses.

Little St. Germain Lake, Wis., consists of four main basins separated by narrows. This study monitored lake water quality, identified phosphorus sources, determined spatial and temporal distribution of oxygen, evaluated the effectiveness of winter aeration systems, and modeled groundwater/lake-water interactions.

Anvil Lake is a relatively shallow, high-quality lake whose water level has dropped dramatically in recent years, adversely affecting the recreational and aesthetic values of the lake. The USGS is developing detailed water and phosphorus budgets, determining groundwater contributions, modeling likely responses to changes in phosphorus loading, and assessing the effect of climate on water quality.

Lake Superior tributaries in Bayfield County, Wis., have accelerated erosion and sedimentation influenced by changing land use, steep slopes, erodible soils, and flashy runoff. This project assessed the geomorpology of five tributaries, identified problem areas, and assessed rehabilitation alternatives and watershed management strategies specifically related to the rehabilitation of brook trout.