NERL Research Abstract

EPA's National Exposure Research Laboratory
GPRA Goal 8 - Sound Science
APM # 599

Significant Research Findings

Draft Protocol/Prototype for Estimating Loadings of
Sediments to Surface Waters by the Office of Water,

Regions, and States

Purpose	A primary environmental focus for the Office of Water is source

characterization of sediments and the resulting loadings from watersheds, and
the role of sediments in impairing water quality and aquatic habitat. The goal
of this research is to design a simplified modeling approach for characterizing
and prioritizing sources of sediment loadings from watersheds in the United
States. The modeling approach will enable States to better assess the inclusion
of various watersheds as impaired, as required under Section 303(d) of the
Clean Water Act.

Research The modeling approach will develop the ability to determine whether local
Approach water quality problems due to excessive sediment loading potentially exist in a
watershed (basin), and demonstrate the application of the recommended
approach/models for predicting changes in sediment budgets in response to
changes in proposed watershed Best Management Practices (BMPs), including
precision farming, agricultural land management, and other traditional
agricultural BMPs.

A simplified approach is developed to evaluate sediment loadings from
watersheds and selected land segments within the United States. The proposed
model(s) consist of sediment loadings from the Revised Universal Soil Loss
Equation (RUSLE). The model is being developed in a spreadsheet format that
can be run on most laptop computers or from any website. Simplified inputs
are required. The program provides the input sediment loadings to the stream
reach.

The proposed spreadsheet model is designed to enable personnel involved in
evaluating the impacts of such things as human activities, agricultural practices,
and land use changes on achieving a Total Maximum Daily Load (TMDL) for a
stream in which the impairment was caused by sediment.

National Exposure Research Laboratory - September 2000

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Major

Findings and
Significance

This model will serve as a demonstration of how models can be used to address
TMDL development and evaluating alternative management strategies for
sediment delivery issues for watersheds and stream segments.

This spreadsheet model is written in Visual Basic and designed to run on PC
platforms using Windows(95, 98, 2000, NT) operating environments. The
model contains a watershed database consisting of HUC 8 scale watersheds in
the U.S. which is subdivided by state boundaries. The watersheds are displayed
on a map and point and click by mouse control is used to access smaller scales
(state boundaries, etc.). A comprehensive soils data base containing over
23,000 soils series for the U.S. and a major land resource area databases for
delineating major stream segments in the watersheds is also part of this
modeling package. A comprehensive on-line user help tool for estimating the
model input parameters was developed for this tool. The help tool will provide
guidance and on estimating the appropriate model parameter for estimating
sediment delivery.

This tool is designed for screening assessments of sediment transport to
streams. Local knowledge of land segment areas will be required of the user in
order to run this system.

Research

Collaboration

and

Publications

The simulation strategy was developed by a research team at the Ecosystems
Research Division, including Robert F. Carousel, and support from the Office
of Water contract 68-C6-0009.

Future
Research

Peer review of the model is ongoing.

Inquiries concerning this research may be directed to:
Robert F. Carousel

U.S. Environmental Protection Agency
National Exposure Research Laboratory
Athens, GA 30605
Phone: (706)355-8065
E-mail: carousel.robert@epamail.epa.gov

National Exposure Research Laboratory - September 2000

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