The Mill River is located in Essex County, with its headwaters in the Georgetown Rowley State Forest and other tributaries within the Town of Rowley. Flowing under Route 1 near the village of South Byfield, the Miller River eventually empties into Plum Island Sound. The Mill River Watershed covers approximately 14 square miles of lightly populated rural properties and includes Batchelder, Taylor and Ox Pasture Brooks. Landmarks along the River include the Jewell Mill Dam near the Route 1 and Glen Street, and the Governors Academy further north along Route 1.
Anadromous fishes including blue-backed herring and possibly sea run brook and brown trout are present in the Mill River during spawning periods. In early May each year large migrations of herring can be spotted immediately below the Jewell Dam which blocks their passage upstream into a more expansive spawning habitat. Spawning nests or “redds” of sea run trout have been identified from time to time below the Dam. The Dam confines spawning activities to downstream pools, exposing large concentrations of herring to predation by seagulls, herons, and other birds of prey.
The private owners of the Jewell Mill Dam have expressed a desire to facilitate the upstream movement of spawning fish past the Dam. Although Dam removal is not an alternative, different forms of fish passage are feasible and have been discussed with MA Department of Marine Fisheries. State authorities have expressed the belief that water conditions above the Jewell Mill Dam may not be conducive to spawning activities due to inconsistent water quality. The Chapter and its members are devoting their time and expertise to demonstrate to the authorities that the upper Mill River is a suitable spawning habitat. There are a number to tasks to be undertaken to achieve this result. Assuming that a convincing case can be made, next steps would include the design and installation of an effective form of fish passage device.
Project #1 –Water Quality Study
This project is part of the Chapter’s effort to develop a comprehensive profile of the habitat conditions in and around the Mill River. It includes the monthly collection of water quality data (May through September) over a two-year period at several locations upstream of the Jewell Mill Dam to determine whether conditions will support herring migration and spawning, applying the state’s Technical Report 42 standards. Likewise, collected data will inform the Chapter on whether the habitat is conducive to spawning by cold water species including, in particular, sea run brown and brook trout. If the data is favorable, a case will be made with MA Marine Fisheries for the creation of a fish ladder at the Jewell Mill Dam. Preliminary investigation of the ladder design suggests that step-pools could be created using natural materials at the Dam site, enabling herring and trout to make their way over the Dam and into many miles of upstream habitat.
Project #2 -Macroinvertebrate Study
On May 25, 2017, five seniors from the Governors Academy and science teacher Lisa Borgatti with oversight from the Chapter, gathered macroinvertebrate samples from two different locations on the Mill River at the Jewell Mill. Applying the collection process set out in Ipswich River Watershed Association’s state-approved Standard Operating Procedures for Macroinvertebrate Sampling and Analysis (August 2013, Version 2) and after receiving training from IRWA’s Ryan O’Donnell, the students recorded primary and secondary habitat conditions (depth, river bottom characteristics, velocity, channel alteration, sedimentation, bank conditions and vegetation). Equipped with waders, nets and collection tools, the students next stepped into the Mill River to collects “bugs”. This process included teams of students positioning nets in the current, removing and brushing rocks to dislodge organisms and digging into the river bottom to free up burrowing organisms. Captured bugs were then collected and catalogued. This baseline of data will be compared to the results of further collections in subsequent years to gauge the evolving health and species diversity of the River.