Types of Nonpoint Source Polution

Nitrogen and phosphorus are nutrients that help plants and animals live and grow. But in excess, these nutrients cause pollution, creating one of the greatest threats to the health of our waterways. These two nutrients are of particular concern in Virginia because they are used on agricultural lands. When these nutrients accumulate from excessive animal waste and use of fertilizers, they become major culprits of nonpoint source pollution, as they are carried in stormwater runoff. Urban and suburban areas also are culprits when nutrients from poorly maintained home septic systems enter the groundwater supplies, and when animal feces, pesticides and fertilizers dump into our waterways during rainstorms.

Nutrients over-enrich waterways during these rainstorms, causing algal blooms that deplete oxygen in the water, and destroy aquatic habitat by clouding the water and coating underwater grasses. When there is no oxygen or light in the water, grasses begin to die, as do finfish and shellfish. The result can lead to an unhealthy waterway, not suitable for swimming or fishing.