Take Cover! (With Vegetation)

By Marguerite Huberbuffer

Take cover!

It’s a phrase you yell to protect against something headed your way. But did you ever think that phrase could be applied to pollutants? Well, it can – vegetative cover acts as a defense against non-point source (NPS) pollutants, protecting our lakes, streams, and water bodies.

Vegetative filter strips and riparian buffers  are conservation practices that help control the amount of sediment and chemicals that are transported from agricultural fields into water bodies. They slow down the speed of runoff and capture nutrients, keep more nutrient-rich topsoil on farmers’ fields, and reduces impacts on downstream ecosystems.

To improve water quality in large watersheds, conservation managers need to know what the problems are, where the pollutants originate, and what conservation practices work best.  However, investigating all of these factors at the watershed-wide level is a very difficult and complex task. This is why EPA is working with partners to supplement an existing watershed simulation model to estimate the efficiency of riparian buffers.

USDA’s watershed simulation model, Annualized Agricultural Non-Point Source Pollution (AnnAGNPS), is used to evaluate the effect of farming and conservation practices on pollutants and help decide where to put these practices.  AnnAGNPS also predicts the origin and tracks the movement of water, sediment, and chemicals to any location in the watershed.

To supplement this model, researchers from EPA, USDA, and Middle Tennessee State University developed a Geographic Information Systems–based technology that estimates the efficiency of buffers in reducing sediment loads at a watershed scale.

With the addition of this AGNPS Buffer Utility Feature  technology to the USDA model, researchers and watershed conservation managers can evaluate the placement of riparian buffers, track pollution loads to their source, and assess water quality and ecosystem services improvements across their watersheds.

Riparian buffers and other vegetative cover, such as filter strips, are considered an important, effective, and efficient conservation practice that has been shown to protect ecosystem services at a local level. However, their full impact on a watershed-scale is still subject to ongoing research.


About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Beyond The Plains – Modeling Non-Point Source Pollution in The Utrata Watershed In Poland

By Walt Foster

Being in the middle of the United States, one would think there were few opportunities to get involved with activities beyond our country’s borders.  But with the breakup of the Soviet Union and Warsaw Pact in the late 1980’s and early 1990’s I had an opportunity to assist EPA’s Office of International Affairs because of our region’s particular expertise with spatial science and agricultural. 

 In cooperation with Iowa State University, and funded by a grant from the Marie Curie Foundation, I worked on a project in the Utrata watershed outside Warsaw, Poland. The project involved development of a modeling methodology to support agricultural watershed management which could be adapted to other rural watersheds throughout Poland.



We used the Agricultural Non-Point Source Pollution (AGNPS) model, a cell-based runoff model widely used in the U.S. to predict the effects of various land management strategies on nutrient and sediment runoff in small to medium sized agricultural watersheds.      

The inputs to the model included such information as topography, soils, hydrography, and land use, while outputs were predicted nutrient and sediment loads.  This model allowed identification of locations where a high potential for non-point source runoff existed, as well as the ability to model the results if various land management practices were employed to reduce runoff.   

At the time this was particularly challenging as data was much more difficult to come by than it is today, processing was more difficult because of hardware and software limitations.  

The completed model ultimately enabled watershed managers in Poland to rapidly target non-point source problem areas and evaluate land management practices for their potential impact on these target areas. The model also encouraged the development of water policy that supported sustainable development in rural areas of Poland.

Over the last twenty years the tools, techniques, and information have improved, but the experiences in both the U.S. and Western European have continued to show that that a management approach that integrates social, economic, and environmental processes at the watershed scale is often the most effective approach to dealing with water quality issues.  You can order a free copy of EPA’s Handbook for Developing Watershed Plans to Restore and Protect Our Waters from the National Service Center for Environmental Publications (NSCEP). Contact NSCEP at 800-490-9198 or by e-mail, You can also download the Handbook here.

Walt Foster has been with the GIS program in EPA Region 7 since its inception except for an hiatus during which he served as the NEPA section chief and worked with EPA’s Office of International Affairs on environmental projects in eastern Europe.  More recently he worked on a series of projects with a number of cooperating agencies and NGOs designed to characterize the ecological state of Region 7 and identify priority ecological resources for regional programs to use in their planning and response activities.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.