Nonpoint Source Pollution Programs

Introduction to Nonpoint Source Pollution (NPS)

Nonpoint source pollution refers to contamination that does not originate from a single, identifiable source, but rather from diffuse sources such as rainfall or snowmelt moving over and through the ground. This type of pollution can carry natural and human-made pollutants into lakes, rivers, wetlands, coastal waters, and groundwater, impacting water quality and ecosystem health.

• Key Term: Nonpoint Source Pollution (NPS) – Pollution from diffuse sources, such as runoff from agricultural fields, urban areas, and roads.

• Example: Fertilizers, pesticides, and pet waste washed into streams after rain.

Section 319 Nonpoint Source Program

The 1987 amendments to the Clean Water Act established the Section 319 Nonpoint Source (NPS) Program to address NPS pollution. The program provides grant money and technical assistance to states, territories, and tribes to support a wide variety of activities, including education, training, planning, and implementation of best management practices (BMPs).

• Types of Assistance: Financial, technical, planning, coordination, and facilitation.

• Program Type: Non-regulatory.

• Statute: Clean Water Act and Safe Drinking Water Act.

Program in Action

The NPS program supports projects such as watershed protection, restoration of aquatic habitats, and reduction of bacteria and nutrient pollution.

• Example: Restoration and protection activities in the Delaware River and New York City’s drinking water supply.

• Best Management Practices (BMPs): Strategies such as riparian buffers, cover crops, and urban green infrastructure to reduce runoff and improve water quality.

Building Resilience through NPS Programs

NPS pollution is a major threat to water quality, affecting drinking water, recreation, fisheries, and wildlife. Programs promote resilience by supporting watershed planning, conservation, and climate adaptation.

• Conservation Approaches: Nature-based solutions, climate adaptation, and hazard mitigation.

• Example: Projects funded under Section 319 with climate adaptation plans.

Federal and State Agency Support

Agencies such as the EPA and FEMA collaborate to provide hazard mitigation and environmental management, improving community resilience and water quality.

• Memorandum of Agreement: Framework for joint activities related to hazard mitigation and NPS pollution.

• Hazard Mitigation Assistance: Funding for eligible mitigation measures that reduce disaster losses and improve water quality.

Total Maximum Daily Loads (TMDLs)

Overview of TMDLs

TMDLs are regulatory tools used to determine the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards. They allocate pollutant reductions among point and nonpoint sources.

• Key Term: Total Maximum Daily Load (TMDL) – The calculated maximum amount of a pollutant allowed in a waterbody.

• Purpose: To ensure waterbodies meet water quality standards by controlling pollutant loads.

TMDL Equation

The TMDL equation is expressed as: Where:

• WLA: Waste Load Allocation (point sources)

• LA: Load Allocation (nonpoint sources and background)

• MOS: Margin of Safety

Triggers for TMDL Development

Under the Clean Water Act, states must develop TMDLs for all waters identified as impaired (Section 303(d) list).

• Impaired Waters: Waterbodies not meeting water quality standards due to excess pollutants.

Responsibility for TMDL Development

States are generally responsible for developing TMDLs and submitting them to the EPA for approval. Third parties may assist, but EPA must approve all TMDLs.

• EPA Role: Reviews and approves/disapproves TMDLs; if disapproved, EPA develops a replacement TMDL.

Development Process for TMDLs

The objective is to determine the loading capacity of the waterbody and allocate the load among sources so that water quality standards are met.

• Steps:

  1. Identify all contributing sources of pollutants.

  2. Estimate the total allowable load.

  3. Allocate reductions among sources.

  4. Include a margin of safety to account for uncertainty.

• Approaches: Range from simple mass balance calculations to complex modeling.

Public Participation in TMDL Development

Public involvement is encouraged throughout the TMDL process, including data provision, review, and commenting on draft and final documents.

• Importance: Local knowledge can improve watershed management and implementation of solutions.

Components of a TMDL Document

• Waterbody and pollutant identification

• Applicable standards and targets

• Loading capacity and allocations

• Margin of safety

• Seasonal variation considerations

• Rationale for allocations

• Monitoring plans

• Implementation plans

• Public participation summary

After EPA Approval

Once approved, TMDLs guide regulatory actions, permitting, and implementation of pollution controls to restore water quality.

• Example: NPDES permits may be issued based on TMDL allocations.

HTML Table: Key Elements of TMDL Development

Summary

• Nonpoint source pollution is a major challenge for water quality management, addressed through federal, state, and local programs.

• The Section 319 NPS Program provides resources for education, planning, and implementation of best practices.

• TMDLs are regulatory tools that set pollutant limits for impaired waters and guide restoration efforts.

• Public participation and interagency collaboration are essential for effective water quality management and resilience building.

Key Terms

• Nonpoint Source Pollution (NPS)

• Total Maximum Daily Load (TMDL)

• Best Management Practices (BMPs)

• Margin of Safety (MOS)

• Impaired Waters

Additional info: Academic context and definitions were expanded for clarity and completeness.