Where This Occurs: Lakes and Rivers

Nutrient pollution, often caused by excess phosphorus and nitrogen, can build up in our nation's lakes, ponds, and streams. 

EPA's 2022 National Lakes Assessment found that, across the country, half of lakes were in poor condition with elevated phosphorus levels, and 47% were in poor condition with elevated nitrogen. 

When river or stream currents are slow, or when waters are stagnant, nutrients, sediment, and particles accumulate, increasing the chances of harmful algal growth. EPA's 2018-2019 National Rivers and Streams Assessment found that nutrients were the most widespread stressor, and 42% of the nation's river and stream miles were in poor condition with elevated phosphorus levels while 44% were in poor condition with elevated nitrogen levels. 

Lakes and rivers are common sources for drinking water supplies. Both algae and high nitrate levels cause problems in sources of drinking water. 

Case Study: Lake Oneida, New York: Agricultural Environmental Management Projects Reduce Excess Nutrients

Algal blooms and rooted vegetation impaired recreational uses of New York's Oneida Lake, causing New York to add the lake to its Clean Water Act impaired waters list in 1998. Excess nutrients, specifically phosphorus, from agricultural, urban and suburban runoff contributed to the growth of algal blooms in the lake. Implementing best management practices such as barnyard runoff management systems, manure storage systems, and nutrient and sediment control systems successfully reduced phosphorus loads to Oneida Lake. The New York State Department of Environmental Conservation delisted Oneida Lake because data showed steady declines in phosphorus levels and indicated that the lake supports aquatic life and recreation.

Case Study: Lower Piper Creek and Upper and Lower Goat Creek, Montana

Goat Creek is a tributary to Swan River, which is situated in a heavily forested watershed in northwest Montana. Construction of forest roads and timber harvesting led to sediment and nutrient pollution in Goat Creek, which made the creek unable to adequately support aquatic life. Private development also contributed to this problem due to the removal of wooded areas, the introduction of septic systems and road construction.

The Montana Department of Environmental Quality, a group of partners from the timber industry and federal agencies developed Total Maximum Daily Loads for waters in the Swan Lake Watershed to reduce sediment and nitrogen and phosphorus pollution. Over the past 20 years, efforts have included the implementation of forestry best management practices-establishing drainage catchments along forest roads to intercept sediment in runoff, upgrading old roads, and implementing an erosion control standard by the end of 2015. As a result of these actions, by 2006, Upper Goat Creek was no longer considered impaired due to nutrients.