Eutrophication in Farmington Bay: an Urban Embayment of the Great Salt Lake

The Great Salt Lake lies in a terminal basin, and thus accumulates nutrients and other pollutants produced in its watershed. With the growth of communities in the Wasatch Front, ever-increasing stress is being placed on the lake. Farmington Bay, an embayment lying on the southwest corner of the lake and close to these urban centers, is the initial recipient of pollutants, and receives wastes from over 700,000 people and industry. Nutrient loading to the bay is nearly five times that necessary to cause hypereutrophic conditions. Summer chlorophyll levels are near 100 μg L-1 and Secchi depths are usually less than 0.2 m. Nighttime anoxia is frequent. Nutrient addition bioassays and algal analyses indicate that the bay is usually nitrogen limited, with high salinities precluding nitrogen-fixing cyanobacteria from correcting the nitrogen deficit. Utah State University, working in conjunction with the Utah Division of Water Quality and the Davis County Sewage Improvement District, is studying the system to determine if beneficial uses are impacted by this severe eutrophication. With increasing urban growth and demands on water flowing to the Great Salt Lake, it is important to understand how these changes could impact the ecosystem, and to remedy the situation before beneficial uses are threatened