Great Brook

Streams of the Great Swamp Watershed:
Great Brook

Great Brook arises in Morris Township just to the east of the ridgeline
that runs through Morristown, the Mendhams and Bernardsville.

Part of the easternmost range of the Appalachians and paralleling Route 202, this ridge is the oldest geologic feature of the Great Swamp watershed, having its origins in geological processes that began about one billion years ago and culminated 250 million years ago.

Map of Great Brook subwatershedLike other watershed streams, Great Brook originates in multiple sites, with four tributaries forming its beginnings (See Great Brook map). The westernmost tributary arises just to the west of Route 202 and traverses Routes 202 and I-287 before flowing into a wetland area alongside James Street. After crossing Route I-287, the tributary flows through the 53-acre GSWA Conservation Management Area (CMA). Leaving the CMA, it traverses one of the most biologically active areas of the watershed, identified in the GSWA’s 1997 publication Saving Space as having critical ecological importance. In addition to showcasing some of the region’s best rural vistas, the area is composed of wetlands, mature forests, and meadows, has a high percentage of critical soils, including those with severe erosion potential, and appears to support an abundance of diverse wildlife.

It is in this area that the tributary joins with the second major Great Brook tributary, and, further east, with the third. Both of these tributaries arise in more heavily developed regions of Morris Township, making protection efforts there and further south on the stream of utmost importance. The fourth tributary arises in Harding Township and runs alongside Lee’s Hill Road before joining the other three north and west of Silver Lake. Flowing south and east at that point, Great Brook in its entirety is impounded at Silver Lake in Harding Township, where it flows over the dam spillway at Blue Mill Road. Below Blue Mill Road, the brook flows alongside Dickson’s Mill Road south of Harding Land Trust property, a 30-acre vegetated floodplain home to snapping turtles, herons and ducks. The spillway aeration at Silver Lake and the dam’s ability to trap sediment both benefit the brook further downstream, making the area biologically rich and aesthetically pleasing. Great Brook then crosses Village Road and enters Great Swamp.

Great Brook is a critical stream for Great Swamp. It originates in urban and suburban areas, where it is intensively subject to the non-point source pollutants that threaten Great Swamp’s health, and at the same time it provides a home for some of the richest plant and animal life in the watershed. Disturbingly, the ongoing Stream Monitoring Program has shown that Great Brook’s water quality is variable at best. The Ten Towns Committee’s 2002 water quality standards note that the brook meets baseflow water quality standards in just two of six areas (Nitrates and Total Nitrogen), while meeting stormflow standards for three of six areas tested (Nitrate, Total Kjeldahl Nitrogen, and Total Nitrogen). Interestingly, after a discouragingly poor year for Great Brook in 2001, test results for two sites on the brook showed marked improvement.

These variable results suggest that Great Brook, located on the spectrum between the relatively pristine Primrose Brook and Upper Passaic River and the seriously degraded Loantaka and Black Brooks, is today at a crossroads. Further development along its banks and on properties over which runoff flows into its sub-watershed will most certainly add to this degradation, while protection efforts and remediation of existing developed areas may well improve water quality. A Ten Towns Committee-sponsored study of the Great Brook and its sub-watershed identified over 100 problem areas along Great Brook and its tributaries in 2001; with over 35% of Great Brook’s headwaters already heavily developed, efforts to protect the brook are timely and crucial.

Great Brook on April 16, 2007, after the Nor’easter

Great Brook at the bridge, April 2007

At the bridge

Great Brook upstream from the bridge

Upstream from the bridge

Ongoing efforts to protect and remediate upstream areas provide reason for optimism. Two examples are instructive. The New Jersey Conservation Foundation currently owns a 9-acre parcel in Morristown roughly bounded by the Spring Brook Country Club, Wetmore Avenue, and the northern-most edge of Vanderpool Drive alongside the third Great Brook tributary. This parcel is comprised of wetlands together with higher elevations that would allow passive recreation such as hiking and birdwatching. Also largely comprised of wetlands, an environmentally sensitive 2.5-acre parcel on Gillespie Lane currently in private ownership abuts the NJCF parcel on the southeast side. This parcel is directly threatened with development. The GSWA and NJCF, together with local residents, have collaborated for a number of months on methods for preserving this parcel. To that end, both organizations have met with municipal officials to discuss conservation options, including the purchase of the property or outright condemnation. (As an active partner with GSWA in this preservation effort, the Town of Morristown is at present seeking funds to purchase the property through the Morris County Open Space Trust Fund.)

South of the NJCF property beyond an adjoining residential area sits Foote’s Pond and the municipal open space that surrounds it next to the Thomas Jefferson Elementary School. Since 1999, the Foote’s Pond Revitalization Project has worked to restore the pond, construct trails, replant vegetation, and develop an educational curriculum for Morris School District students and local residents. Vital aspects of that project are to remediate the dam and outflow structures and the pond’s environs so as to improve the water quality.



Black Brook Log Sheet
Upper Passaic River

Black Brook
Loantaka Brook
Primrose Brook