Ellen Groth
- May 20
- 4 min read

Nonpoint Source Pollution Doesn't Have to be Complicated

Example of NPS from grass clippings in stream — NPS from Improper Mowing Practices, Sulphur Draw, San Angelo, Texas

Nonpoint source pollution or “NPS” is pollution that results from many sources without a single point of origin. NPS is typically caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, finally depositing them into lakes, rivers, wetlands, coastal waters and ground waters.

“NPS is the leading cause of water pollution in the United States”

Venn Diagram showing Urban/Agricultural NPS — Two Types of NPS

Urban NPS Simplified

Most urban areas include impervious surfaces such as roads, building roofs and parking lots.

This means that rainfall and other precipitation has difficulty soaking into the ground and the polluted runoff ends up in local storm drains, streams and rivers.

In woodland areas, vegetation can reduce runoff and improve water quality because rainwater is absorbed and filtered as it occurs.

Pollutants commonly found in urban runoff have been known to harm fish and wildlife (1, 2), kill native vegetation, contaminate drinking water and make recreational areas unpleasant and potentially unsafe (1, 2).

Images showing things that create Urban NPS

Urban NPS can come from:

Excess fertilizer and other lawn chemicals
Oil, grease and toxic chemicals found on city streets
Sediment from construction sites
Open paint cans in alleys & curbs
Soil erosion
Improperly disposed of household detergents & cleaners
Pet waste
Un-bagged grass clippings and leaves

“A typical city block can generate 5X more runoff than a woodland area of the same size” Source: Protecting Water Quality from Urban Runoff, EPA 841-F-03-003

Agricultural NPS Simplified

Agricultural NPS is a type of pollution that comes from agricultural runoff. NPS pollution can include naturally occurring contaminants or those from human activity. Common pollutants include sediments, agricultural chemicals, and salts. See list below.

Images that show things that create Ag NPS

Agricultural NPS can come from:

Herbicide & Pesticide Application
Irrigation Methods
Overgrazing
Animal waste
Sediment from Erosion
Poorly located or managed animal feeding operations

“Runoff from farms is the leading source of impairments to surveyed rivers and lakes”

Source: Protecting Water Quality from Urban Runoff, EPA 841-F-05-001

NPS Abatement Management

Congress amended the Federal Clean Water Act in 1987 and established a nationwide program to control nonpoint sources of water pollution. As a result, states were tasked with developing and implementing NPS programs.

Section 319(h) grants were created to allocate funds and provide guidance to assist states, territories and tribes in developing and implementing NPS control programs. States submit their prospective plans, and if the plan is consistent with EPA’s grant conditions, funding is awarded.

In Texas, nonprofit organizations, state agencies or political subdivisions that include cities, counties, school districts, state universities & special districts, are eligible for grant funding. Individuals and for-profit business organizations may participate in projects as partners or contractors but cannot apply for direct funding.

Funds are managed by the Texas Commission on Environmental Quality (TCEQ) and the Texas State Soil & Water Conservation Board (TSSWCB). Both agencies release a Request for Grant Applications (RFGA) annually.

Once the grants are awarded, these agencies are responsible for oversight and program management during the project period, which typically lasts 3-4 years.

While projects to prevent or reduce NPS pollution in states is still voluntary, Texas has implemented a multitude of successful NPS efforts since program inception. These programs use statewide and local strategies to protect its water resources.

NPS Abatement Measures: Two Strategies

Abatement strategies utilize Best Management Practices or “BMPs” and there are two types of BMPs. Structural BMPs address the problem after it is created and Non Structural BMPs try to prevent pollution before it occurs. Both are crucial for NPS abatement.

STRUCTURAL BMPs

are physical features constructed to control the volume of runoff or reduce pollutants present in runoff.

NPS Abatement Demonstration Ponds in San Angelo, Texas — Demonstration Project, Filtration Ponds, N. Concho, San Angelo, Texas

NON STRUCTURAL BMPs

do not involve a structured solution but focus on education & outreach, watershed planning, and modifying habits and behaviors.

Photo of KSAB Annual Trash Off 2023 Volunteers — UCRA Staff & KSAB Volunteer @ Annual "Don't Mess with Texas" Clean Up Event

UCRA has been involved in NPS abatement for thirty years

UCRA was awarded our first cycle of EPA funding for a large scale NPS abatement project in San Angelo, Texas in 1994.

The funding was for a structural BMP to be built adjacent to the North Concho River in Civic League Park. A Gabion Dam was constructed to catch debris during high velocity rainfall events before it reaches the river. An education and outreach initiative was conducted in tandem with the construction of the BMP.

When the grant cycle ended, the City of San Angelo took over long term maintenance and the structure continues to have lasting effects in mitigating NPS.

Photo of Gabion Dam, an NPS Abatement structure in San Angelo, Texas on the river — Gabion Dam in San Angelo, Texas, N. Concho River, Downtown

Since this initial project, UCRA has been recipient of multiple NPS grants in Tom Green, Coke and McCulloch counties. The projects have included structural and nonstructural BMPs and are ongoing.

Partnerships are key in any successful project and UCRA has cultivated long lasting collaborations as a result of our efforts with -