Department of
Environmental Quality

Unlike pollution that is discharged directly from a pipe into surface waters, nonpoint source (NPS) pollution comes from many diffuse sources. It generally does not have a single point of origin. NPS pollutants can be natural, such as sediment, or human-made, such as chemicals and toxics. They are generally created in or on the land and carried off by stormwater runoff when it rains or the snowpack melts. As the runoff moves, it picks up and carries away the pollutants, finally depositing them into nearby surface waters, including streams, rivers, and lakes. Nonpoint pollutants may eventually leach into ground water. This hazard is especially important because more than 90 percent of Idaho's drinking water comes from ground water.

Sometimes nonpoint pollution can be traced to several sources; sometimes it cannot be traced at all. Common nonpoint pollutants and their sources are:

• Household chemicals and soaps running off driveways, roofs and yards into streets and down storm drains directly to streams and rivers
• Fertilizers and pesticides running off agricultural lands and urban areas such as yards, parks, golf courses and landscaped areas
• Oil, anti-freeze, and other toxic materials running off roadways into storm drains or directly into streams
• Sediment from improperly managed construction sites, crop and forest lands, and eroding streambanks
• Salt from irrigation practices and acid drainage from abandoned mines
• Bacteria and nutrients from livestock, pet wastes, and faulty septic systems

Idaho's Nonpoint Source Management Program

DEQ developed Idaho's initial nonpoint source program in 1989 and has ambitiously pursued its implementation, dedicating personnel and monetary resources to the advancement of nonpoint source water pollution control activities. Learn more.

Impacts of Nonpoint Source Pollution

Nonpoint source pollution can have varying impacts on the environment. It can damage fish, wildlife and their habitat, promote excessive weed growth, generate odors, and degrade Idaho's scenic beauty and recreational opportunities. Fish habitat can be negatively impacted, for example, when sedimentation occurs as particles settle out, fill in streams, lakes and wetlands, and cover up habitat. Fish can be stressed or even killed in nutrient-enriched waters as dissolved oxygen is depleted by excessive plant growth. Thick beds of algae also can use up oxygen, block out sunlight to aquatic life below, and impair beneficial uses (such as swimming and fishing) of Idaho waters.

Prevention of Nonpoint Source Pollution

We can all work together to reduce and prevent nonpoint source pollution. Some activities are federal responsibilities, such as ensuring that federal lands are properly managed to reduce soil erosion. Some are state responsibilities, such as developing legislation to protect water quality. Others are best handled locally, such as by zoning or erosion control ordinances. And each individual can play an important role by practicing conservation and by changing certain everyday habits.

§319 Subgrants in Idaho

Section 319 of the Clean Water Act established a grant program under which states, territories, and tribes may receive funds to support a wide variety of nonpoint source pollution management activities, including technical assistance, financial assistance, education, training, technology transfer, demonstration projects, and monitoring to assess the success of specific nonpoint source implementation projects. DEQ is the state agency responsible for administering the §319 subgrants program in  Idaho. Grants are awarded annually on a competitive basis.

Pre-applications and applications for the 2013 grant
cycle are now being accepted through May 6.
Final applications are due August 1, 2012.
Approximately $1.9 million is expected to be available
for awards of up to $250,000 each in the 2013 cycle.
Learn more.