Natural Resources Planning

Four Mile Brook Watershed Assessment

Project Overview

Four Mile Brook is a coldwater stream that drains a 4.8 mile watershed, most of which is located in Northfield, Massachusetts. The brook supports a population of native brook trout and blacknose dace as well as Atlantic salmon. In the last five years, two major flooding events in the watershed provided dramatic evidence that a watershed assessment and management plan are needed. Tropical Storm Floyd dumped approximately 9 inches of rain over the Four Mile Brook watershed and surrounding areas during a 24-hour period in September 1999. The brook responded by overtopping its banks and flowing down Four Mile Brook Road. The road was severely undercut and scoured by the raging water which then deposited its load of sediment (road material, fill, etc.) into the existing downstream stream channel for an estimated distance of 1,000 linear feet. Several homes were also flooded during this storm event. During the summer of 2000, several intense rainfall events caused additional flooding, erosion and sedimentation of the brook.

Although much of the watershed is still forested, sediment-laden runoff is flowing into the brook. There are numerous road crossings, including small bridges and culverts of various sizes, that appear to be sources of nonpoint pollution and, in the case of the culverts, potential impediments to fish and wildlife passage. Accelerated bank erosion along the brook has resulted in the loss of riparian vegetation, including bordering vegetated wetlands, which provide important breeding and escape cover habitat for many aquatic and terrestrial species. The steep gradient of the upstream reaches of the brook and the thin soil cover have made the natural hydrology of the watershed "flashy" in response to rainfall or snowmelt events.

The project for this watershed includes: a comprehensive watershed assessment; a macroinvertebrate sampling program; a public education and outreach effort; and a watershed management plan, which will prioritize problem areas in the watershed and provide recommendations for mitigation or restoration projects. Our project partners include: Michael Cole, Ph.D., a professional Aquatic Ecologist and Fisheries Biologist, the Town of Northfield, and local volunteer watershed residents and stewards. This project offers several opportunities for volunteer involvement, including participating in the field work required for both the watershed assessment and the macroinvertebrate sampling program. It is the local efforts of volunteer watershed stewards that will help to ensure that the recommendations that come from this project will be implemented.

The Town of Northfield is eager to work with other stakeholders to address nonpoint pollution and encourage well-planned development in this sensitive watershed. The Town is committed to finding a long-term solution to the erosion and sedimentation problems and to investigating innovative approaches to reducing nonpoint pollution in the watershed. The Town of Northfield has pledged $5,000 towards conceptual engineering designs for priority roadway improvement projects that would reduce nonpoint pollution.

Current Activities

With the field work, GIS mapping, and water quality sampling program completed, FRCOG staff is working with an Advisory Committee to evaluate the data and develop a Watershed Management Plan.   FRCOG and the Advisory Committee are also reviewing draft conceptual engineering designs for road improvement projects that would reduce sediment deposition to Four Mile Brook.

Future Plans

Because FRCOG was able to complete some of the project tasks under budget, the MA DEP approved the FRCOG’s request to use $5,000 of the grant funding to hire a consultant to further evaluate high hazard areas in the watershed.   These locations were identified as areas of severe bank erosion and flooding potential adjacent to Four Mile Brook Road that are contributing sediment to the brook and threaten the integrity of Four Mile Brook Road.  Dr. John Field, a Fluvial Geomorphologist, will evaluate these areas and provide recommendations to the FRCOG and the Town of Northfield.

Page Last Updated: March 28, 2008

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