“The USGS provides local, State, and Federal agencies with top quality data and accurate reporting that both the farming community and the environmental community can trust. NAWQA’s ability to look at water quality over the long term helps to evaluate the effectiveness of water-management decisions, conservation activities, and certain farming practices that are used to reduce sediment and runoff off agricultural nutrients and chemicals from fields. (National Leader for Clean Water Program, USDA Natural Resources Conservation Service)

USGS Circular 1265, Water Quality in the Nation's Streams and Aquifers--Overview of Selected Findings, 1991-2001