Rivers
Estuaries
An estuary is where saltwater from the ocean and freshwater from a river meet. When saltwater and freshwater mix together, it is called brackish water. Estuaries are an important ecosystem where salt marshes thrive, providing habitat for crabs, clams, fishes, and birds. They protect our coasts by acting as a natural barrier and reduce coastal flooding. These marine environments help maintain healthy water quality by acting as a sponge, filtering pollutants from stormwater runoff. Salem Sound Coastwatch acknowledges the people of the Massachusset Tribe as the original inhabitants of the Salem Sound estuary.
Salem Sound Watershed’s Rivers
Freshwater entering Salem Sound flows from smaller sub watersheds into the Danvers River, the harbors of Manchester-by-the-Sea, Beverly, and Salem. The Danvers River receives freshwater from the Crane River, Waters River, and Porter River. The only river in Beverly that flows into the Danvers River is the Bass River. Salem and Peabody’s North River flows into the Danvers River and is the largest freshwater contributor to Salem Sound. Manchester-by-the-Sea’s Sawmill Brook exits into Manchester Harbor. The South River and Forest River flow into Salem Harbor.
North and South Rivers
The 11.5 square mile North River watershed that collects water from Peabody and Salem, is the oldest urban river. Since the closure of the last tannery in 1980, the quality of the North River has improved. However, issues continue to persist in the North River due to urban expansion.
The North River’s original estuary floodplain has been filled since the 19th century to accommodate train tracks. The river was channelized, often making it unrecognizable as a river. With only one remaining natural section of river along Harmony Grove Road, there has been a disruption for marine habitats, various plant and animal species, and has directly affected erosion downstream.
Portions of the North River are left unseen; it was buried underground in culverts due to infrastructure such as roads, buildings, and other urban development. Culverts restrict water, increase water pressure and velocity, and remove any viable habitat. During heavy precipitation events, culverts can only hold so much water, which leads to increased flooding.
The South River watershed drains two-thirds of Salem. During the 18th and 19th century, the shorelines and basin of the river were filled to accommodate warehouses, wharves, railroad yards, a train station, and residents. It starts up at Witchcraft Heights, flows down to Salem High School, Salem Woods, and Rosie’s Pond. It travels along long Jefferson Ave. Today, the river emerges from a culvert at the intersection of Lafayette Street and New Derby Street where this channelized section is now the South River walk.
Maintaining Healthy, Safe Waterways
Salem Sound Coastwatch seeks to protect and improve the Salem Sound waterbodies and marshes.
Forest River
The Forest River is Salem’s least impacted river, flowing through wetlands and forests, before entering Salem Harbor. Beginning above Highland Ave, a heavily commercially developed street, the river’s tributaries flow through wooded hills and swamps. From Thompson’s Meadow, the freshwater stream flows into the Salem Conservation Area where it meets the tidal waters of Salem Harbor. Here the Forest River estuary, 126 acres of wetlands, forest, and tidal coves, contains salt marsh, an important ecosystem that protects marine life. It then flows along the Marblehead Forest River Conservation Area and more salt marsh habitat.
Sawmill Brook
The watershed of the Sawmill Brook, a cold-water stream, encompasses two-thirds of Manchester–by–the–Sea and provides drinking water for 40% of Manchester’s residents. Starting south of Route 128 at Millets Swamp, Sawmill Brook flows north under the highway to Cedar Swamp, then turns south, merges with Cat Brook, and flows through the Essex County Club golf course where it is joined by Causeway Brook at Lincoln Street. The brook continues through the densely populated downtown to enter the harbor.
