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Sampling and Modeling Water Quality in the Byram River

Measuring Water Quality by Sampling and Modeling

It is easy to take water quality for granted until beaches are closed, fishing or shellfishing are banned, or drinking water is declared unsafe. We are much better off if problems are handled before reaching a critical point.

a sign showing that an area is closed to shellfishing
Areas that are closed to fishing or shellfishing
are usually due to poor water quality.

Beaches can be shut down, or fishing and shellfishing areas can be closed when pathogens (bacteria and viruses that cause infection or disease) enter the water through untreated waste and sewage discharges. Nutrients, such as phosphorus and nitrogen, can reduce oxygen by causing too many algae and other water plants to grow. Fish and other aquatic life need a certain amount of oxygen in the water to survive.

A well-designed water quality monitoring program can protect the health of people, aquatic life, and other wildlife. It provides information that can help check existing conditions, identify water problems, determine the effectiveness of pollution control programs, and establish watershed goals. Data from a monitoring program can be used in computer models that help find the source of the problems and predict the impact of pollution control efforts.

Project Overview

In 2009, the Interstate Environmental Commission (IEC) received an $87,171 American Recovery and Reinvestment Act (ARRA) grant from DEC to perform sampling and modeling of the Byram River to measure the water quality of the River and its watershed.

The sampling and modeling will help identify and prioritize sections of the Byram River that have pollution problems, assess the impacts of development in the watershed, and identify appropriate pollution control projects. This information will help improve water quality in the Byram River, its watershed, and Long Island Sound, and help protect public beaches and shellfishing beds in the area.

Project Status

GPS device and sampling notes on a bridge over the Byram River
A GPS device was used to verify
sampling locations.
Photo courtesy of IEC.

IEC finished work on this project in December, 2011. The project was completed in two phases:

  1. During phase one, ten locations in the Byram River were sampled four times each: twice during dry weather and twice during wet weather. The samples were analyzed for pollutants such as pathogens, phosphorus, nitrogen, metals, settleable solids, dissolved oxygen, temperature, pH, salinity, conductivity, turbidity and chlorides. At the end of phase one, the sampling results were used to develop and calibrate a water quality model of the Byram River watershed.

  2. During phase two, IEC sampled the same locations twice more, once during dry weather and once during wet weather. The results from the second round of sampling were used to validate the water quality model of the Byram River watershed.

Working in partnership with IEC, Columbia University's Earth and Environmental Engineering Department developed the water quality model of the Byram River watershed to help assess the water quality of the river and the watershed. The model is a Geographic Information System (GIS)-based tool that can be used to characterize existing conditions in the watershed, locate areas that contribute the most pollutants, identify pollution control projects ready to be funded, evaluate conceptual green infrastructure scenarios, and assess the potential impacts of new development or redevelopment in the area.

Final Progress Report

When each ARRA 604(b) project is complete, DEC requires a final report summarizing the entire project to be submitted. The report includes a description of the project's goals, work accomplished, and final project outcomes.

To view the final progress report for this project, click the following link:

Water Quality Monitoring and Modeling of the Byram River - Final Report (PDF) (143 KB)

About the Interstate Environmental Commission and Byram River

The IEC is a joint water and air pollution control agency serving New York, New Jersey and Connecticut. Originally formed in 1936 by New York and New Jersey, Connecticut joined in 1941 and the IEC now enforces water and air quality regulations in the three states, with the authority to enforce laws across state lines.

The Byram River is an interstate waterway that flows through Westchester County in southeastern New York, Fairfield County in southwestern Connecticut, and into Long Island Sound via the Port Chester Harbor in Port Chester, New York. The River has a 29 square mile drainage basin and forms the southernmost border between New York and Connecticut. The lower portion of the Byram River is listed on the DEC Priority Waterbodies List as impaired for recreation due to pathogens and nutrients.

Byram River Watershed Data

map of Byram River water sampling locations
Map showing sampling locations
in the Byram River.
Image is from the Byram River Watershed
Model Development report.

The Byram River watershed water quality model is based on EPA's Storm Water Management Model (SWMM), which is a free, open-source program available on EPA's website. A direct link to EPA's SWMM web page is in the "Links Leaving DEC's Website" section of the right-hand column of this page. Project data is being provided to help stakeholders familiar with the SWMM model identify areas that contribute pollutants to the Byram River, and to help prioritize stormwater controls and other management measures that would be the most beneficial. Project data is provided "as is". DEC is not responsible and shall not be liable for damages of any kind arising out of the use of data or information provided, including the installation of the data or information, its use, or the results obtained from its use.

The Byram River Watershed Model Development report, produced by Columbia University's Earth and Environmental Engineering Department, should be reviewed before downloading and using the project data. The report includes an overview of the data that was analyzed; a description of the modeling structure that was used; an explanation of the model construction, calibration, and verification; a summary of baseline flows and pollutant loads; a discussion on the modeling results; and recommendations for additional work to improve the watershed characterization and the accuracy of the model.

Byram River Watershed Model Development (PDF) (3.6 MB)

The zipped file below contains only the SWMM model and data used for this project. This file is 604 MB and will take at least several minutes to download, even with a fast data connection. It contains 370 files and will unzip to nearly 2 GB of data. In addition to the SWMM model input files, the zipped file contains numerous other files that were used to create and calibrate the SWMM model as described in the above report. These files include a collection of existing models, GIS data, rainfall data, flow data, and water quality survey results that may be used to further refine the SWMM model. This zipped file should be saved to your computer and decompressed using an "unzip" program. Please read the Byram River Watershed Model Development report above for additional information before proceeding.

Byram River Watershed Project Data (zip) (604 MB)

Contact Information

Interstate Environmental Commission

311 West 43rd Street, Suite 201, New York, NY 10036