Nonpoint Source Pollution: Section 319 of the Clean Water Act

 

     The Clean Water Act of 1987 includes Section 319 which addresses nonpoint sources of pollution. Nonpoint source pollution (NPS) refers to pollution that does not come from a single source, also known as a point source. NPS usually refers to runoff from activities like crop agriculture, livestock agriculture, sewage treatment, and stormwater runoff from diffuse sources. Runoff comes from snowmelt and rainfall. The EPA has a great National Nonpoint Source Program guide that was published in 2016. The graphics shown here are from that guide. The EPA notes:

 

“NPS pollution is the dominant source of water quality pollution and the leading cause of impaired waters in the United States.”

 

 

Stream Restoration and the Watershed Approach

 

     Stream restoration is a main focus of the NPS program. The watershed approach is a prevailing paradigm of assessing and improving stream health. Watershed-based planning (WBP) is the most sensible approach. Pollutant loads can be better understood by knowing what is entering the streams and where it is entering. Water bodies collect pollutants from multiple sources, both point sources and nonpoint sources. Pollutants also accumulate in sediment in stream bottoms. Best management practices (BMPs) for mitigation and restoration are established but can also be tweaked. Watershed planning with stakeholder and landowner engagement has been a successful approach to stream restoration. County and regional soil and water conservation districts, the USDA, the Natural Resources Conservation Service, and other federal, state, and local agencies may collaborate on these issues. Below is some Section 319 funding information through 2016.

 

 

Agricultural NPS Runoff

 

     As the following graphic shows, most restoration projects deal with agricultural runoff followed by urban stormwater runoff, the bulk of which is construction runoff. There are also many stream channel modification projects. Other projects deal with waste disposal, resource extraction, legacy pollutants, and pollution from marinas. Agricultural pollutants and BMPs for NPS projects are also given below.

 

 

Urban and Suburban Stormwater NPS Runoff

 

     Urban and suburban areas can be more challenging due to “mixed land ownership, heterogeneous land uses and large areas of impervious surfaces.” Section 319 funding includes urban runoff management and implementation of BMPs. One urban BMP is a bioretention rain garden to collect runoff into a small urban water body with aquatic plants.

 

 

Hydromodification

 

     The EPA explains hydromodification very well:

 

“Hydromodification includes the physical modification or degradation of stream channels or banks, wetlands, or lake or coastal shorelines. Streambank and shoreline erosion and channel incision can mobilize and transport sediment, nutrients and other pollutants (e.g., heavy metals and organic pollutants found in urban soils) that can impact downstream water quality.”

 

“Constructing levees, dams and bulkheads and channelizing streams or rivers are examples of direct hydromodification activities. Upstream land uses that create impervious surface areas and consequently increase runoff volumes and velocities indirectly cause hydromodification.”

 

“§319 funds can be used to help restore floodplains, daylight streams that have been piped underground, restore natural shorelines, reestablish stream channel sinuosity and depths, reduce pollutant discharges and increase the resiliency of shoreline areas to climate change related flooding.”    

 

One method of hydromodification uses tiered rock ramps after a dam removal.

 

 

Resource Extraction NPS Runoff

 

     The main source of resource extraction NPS runoff is acid mine drainage (AMD). This degraded acidic water leaches out metals from rock into the water. It comes mainly from coal mines but is also common with minerals mining, sand, and rock mining. AMD also carries significant amounts of sediment into streams. AMD treatment is a long and ongoing process that may utilize various forms of raising the pH with lime dosers and other limestone-based methods. Turbidity curtains may capture sediment. State abandoned mine lands (AML) projects are commonly funded with AML funding and complemented by NPS funding.

 

 

Extreme Weather, Climate, and Climate Change Can Be Factors in NPS Management

     Heatwaves, droughts, wildfires, storms, and flooding can all lead to increased NPS pollution. Heat influences droughts and wildfires. Wildfires increase post-fire erosion rates. Storms increase runoff rates. Floods collect runoff and sedimentation. Post-storm restoration is sometimes advised.

 

 

Section 319

 

     Section 319 requires that all states develop NPS assessment reports, identify waters impacted by NPS pollution, sources of concern, strategies to address NPS pollution, and identify state and local programs that can prioritize and implement NPS pollution control. The EPA thinks that better integration of WBP data with total maximum daily loads (TMDLs) for specific pollutants is needed for better assessment. The Natural Resources Conservation Service (NRCS) does watershed assessments. The Federal Emergency Management Agency (FEMA) does hazard mitigation plans. These assessments and plans should also be integrated into NPS pollution management. Source water protection plans can also be integrated. EPA’s grant award, implementation, and review process are given below.

 

2024 Revisions

 

     The EPA issued some new Section 319 guidelines in 2024 after “two years of stakeholder engagements with Clean Water Act section 319 grantees, sub-recipients of CWA section 319 funding, local community organizations, and other important stakeholders.” The changes mostly involve eligibility for grants.  

 

 

 

References:

National Nonpoint Source Program —a catalyst for water quality improvements. U.S. EPA. October 2016. National Nonpoint Source Program—a catalyst for water quality improvements (epa.gov)

2024 Clean Water Act Section 319 Guidelines. June 28, 2024. Federal Register. Federal Register :: 2024 Clean Water Act Section 319 Guidelines

Nonpoint Source Program and Grants Guidelines for States and Territories. EPA 841-R-24-009. May 4, 2024. U.S. EPA. https://www.epa.gov/system/files/documents/2024-06/2024_section_319_guidelines_final_1.pdf

Polluted Runoff: Nonpoint Source (NPS) Pollution. CWA §319 Grant: Current Guidance. U.S. EPA. May 2024. CWA §319 Grant: Current Guidance | US EPA