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Agricultural Water Quality

May contain: outdoors, nature, animal, mammal, horse, grassland, and field

Across the United States, nonpoint source pollution from agricultural operations is the leading cause of water quality impairment in surface water. While agricultural operations are the largest contributors currently, that also means they present a significant opportunity to improve water quality.

Sources of Pollution 

There are a variety of potential sources of water quality contamination from agricultural operations. Irrigation methods that require a widespread water application and result in return flows of excess water to local streams and rivers, such as certain methods of flood irrigation, can result in significant impacts to water quality such as carrying excess sediment, nutrients, pesticides, and bacteria and raising stream temperatures. Crop and pasture management that results in excessive soil erosion can increase sediment loading to streams during storm events or irrigation. Livestock management that results in excess mud and manure, particularly when close to streams and creeks, as well as livestock entering and crossing streams are additional threats to water quality.

Ways to Improve

Fortunately there are many opportunities to adjust agricultural operations to improve water quality outcomes. Flood irrigation methods can be adjusted or moved away from to decrease water quality impacts. Livestock can be fenced to stay out of streams and provided off-channel water systems; where necessary, stream crossings and access points can be hardened to reduce impacts. Tools such as properly located sacrifice lots can be used to help manage mud during wet seasons, and manure can be managed to be an asset to farm and ecosystem health. Large-scale infrastructure changes such as piping open canals that carry irrigation water can also help prevent water quality impacts, such as increased temperatures or contamination, during water transportation.

Learn more about some of these topics and ongoing work to improve agricultural water quality at the resources on this page.