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Policy Statement 461 - Non-Point Source Pollution

Approved by the Energy, Environment, and Water Policy Committee on February 26, 2018
Approved by the Public Policy Committee on May 6, 2018
Adopted by the Board of Direction on July 13, 2018


The American Society of Civil Engineers (ASCE) supports efforts to mitigate pollution from non-point source runoff into rivers, lakes, wetlands, riparian habitats, coastal and ocean environments, and ground water basins. ASCE recommends:

  • Strengthened education programs for on non-point source pollution.
  • Increased funding of programs, including research for the development of improved and sustainable best management practices (BMPs) including their linkage with water quantity and quality, and their implementation at the watershed level to manage non-point source pollution
  • More effective mitigation measures for both surface water and groundwater pollution.
  • Expanded monitoring and research on non-point source pollution to evaluate the impacts of the pollution in surface water and groundwater.
  • Federal agencies, such as the Environmental Protection Agency (EPA) and the U.S. Department of Agriculture, as well as state and local governments establish best management practices (BMPs) and appropriate legal mechanisms to ensure such practices are implemented.  


EPA has identified non-point source pollution as the nation's largest remaining source of water-quality problems. Non-point source pollution is caused by many sources, including agriculture, forestry, grazing, septic systems, mine runoff, boating and marinas, urban and road runoff, construction, physical changes to stream channels, and habitat degradation. Individuals in their daily activities also contribute to non-point source pollution problems. EPA has reported that agricultural and urban runoff are two of the leading contributors to non-point source pollution.

Addressing non-point source pollution requires a watershed approach that incorporates water quality and quantity to more effectively protect waters of the United States. The science and implementation of green infrastructure BMPs has advanced, and recent studies demonstrate the effectiveness of these approaches, but further research into their performance and longevity on a watershed basis is needed to bring better identify the associated economic and environmental impacts. ASCE has long been involved with advancing our understanding of green infrastructure BMPs and partnered with EPA in 1996 to develop the International Stormwater BMP Database. Unfortunately federal funding was stopped in 2004 for this effort, even though much needs to be done to close the knowledge gap, reduce costs, and ensure sustainability of implementation.

Inadequate management practices that fail to prevent, eliminate, or reduce the effects of non-point source pollution significantly impact water quality and the ecosystem dependent upon it. Polluted waters eventually move through lakes and larger rivers and enter the estuaries and near-shore environments with increasing detrimental effects upon plant and animal life, as well as upon water supplies for human uses. Education is the first step in mitigating poor practices, followed by the establishment and implementation of BMPs.

Groundwater is an important component of water resources and may also be polluted by non-point sources. Protecting the quality of groundwater should be viewed with the same importance as surface water in the control of non-point source pollution.


Civil engineers play a major role in the design and construction of facilities and infrastructure that can eliminate, prevent, or reduce point- and non-point source pollution to our nation's rivers, lakes, wetlands, ground water basins, and oceans. 

ASCE Policy Statement 461
First Approved in 1997