Groundwater is a major source of nitrate to Chesapeake Bay
Land use, organic carbon in soils, and geology can explain where groundwater contributions are the most important
A new USGS study has identified factors that contribute to high nitrate in base flow in streams flowing into Chesapeake Bay. Land use, organic carbon in soils, and geology were among the most important factors affecting nitrate in stream base flow, based on data collected at 156 stream sites.
The ecosystem of the Chesapeake Bay, a national jewel, has been impaired by nitrate. The source of much of that nitrate is groundwater, which provides base flow to the many streams that flow into Chesapeake Bay. Nitrate can be removed from groundwater by denitrification, a biochemical process that transforms nitrate into harmless nitrogen gas. Organic-rich sediments, often found in riparian zones, enhance denitrification, but dissolved oxygen in groundwater prevents it.
Armed with this information, the study predicted nitrate concentrations during base flow for unmonitored reaches of small streams throughout the Chesapeake Bay watershed. The highest predicted concentrations tended to be near agricultural areas, a potential source of nitrate from fertilizer, and in areas of carbonate rocks, which have geologic characteristics that can facilitate rapid groundwater transport and thereby limit denitrification.
Related Content
National Water-Quality Assessment (NAWQA)
Related Content
- Science
National Water-Quality Assessment (NAWQA)
Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources. - Data
Get Our News
These items are in the RSS feed format (Really Simple Syndication) based on categories such as topics, locations, and more. You can install and RSS reader browser extension, software, or use a third-party service to receive immediate news updates depending on the feed that you have added. If you click the feed links below, they may look strange because they are simply XML code. An RSS reader can easily read this code and push out a notification to you when something new is posted to our site.