Site Monitoring Program

The Site Monitoring Program strives to protect water quality in Cambridge’s water supply reservoirs and tributaries from adverse impacts related to development and land use change, hazardous materials releases, sanitary sewer overflows, and illicit use of Cambridge-owned properties. The program also aims to ensure that reservoir dams remain in good condition. 

The Site Monitoring Program consists of five primary components:

  1. Site Plan Review
  2. Construction and Long-Term Site Management Inspections
  3. Watershed Protection Land Inspections
  4. Dam Inspections
  5. Security and Enforcement

Site Monitoring Program data are tracked in a database and presented in annual Site Monitoring Program reports.

Site Plan Review

Watershed Division staff review project proposals for all major developments in the watershed for compliance with state, local, and federal water, stormwater, and wastewater regulations. Projects are also evaluated for opportunities to implement best management practices (BMPs) to contain potential spills. Watershed Division staff learn about project proposals through partnerships with private landowners, developers, and state and local regulatory entities. Staff also review notices posted by regulatory entities to learn about new projects in the watershed.

Watershed Division staff pay careful attention to stormwater management during the site plan reviews. In-house and United States Geological Survey stormwater sampling results show that stormwater runoff contributes high loads and concentrations of certain pollutants in the Cambridge watershed relative to baseflow. Typical pollutants carried by stormwater are sediments, deicing materials, phosphorus, nitrogen, and car-related substances such as oil, grease, and particulate from tire and brake wear. Structural stormwater BMPs such as bioretention basins can help mitigate the negative impact that impervious surfaces can have on water quality.

Construction and Long-Term Site Management Inspections

Once a project has moved beyond planning and permitting, Watershed Division staff perform site inspections during and after construction to confirm that the site is being managed appropriately. Many projects have permits issued by regulatory bodies with conditions governing construction and long-term site operation and maintenance activities. These conditions may include erosion and sedimentation control requirements; regulatory inspections; maintenance and reporting regarding stormwater management systems; limits on deicing chemicals, fertilizers, or other turf management chemicals; and street sweeping requirements.  

Proper construction and long-term site management is critical to water supply resource protection. Cambridge Water Department involvement in these projects is crucial to ensure the following:

  • All parties involved are aware that they are working near a water supply;
  • No significant impacts on source water tributaries and reservoirs will occur as a result of these projects; and
  • Improvements to existing conditions will be implemented as a result of these projects.

Watershed Protection Land Inspections

Watershed Division manages approximately 1,500 acres of Cambridge-owned watershed protection land in Lexington, Lincoln, Waltham, and Weston plus 162 acres at Fresh Pond Reservation. These lands are managed in a natural state to protect the City’s surface water supply. Watershed Division staff regularly patrol these sites for activities prohibited by state regulation or that have the potential to harm the water supply such as dumping, illicit discharges, encroachments, vegetation damage, erosive activities, abandoned pet waste, and trespassing in sensitive areas.

Dam Inspections

The Massachusetts Department of Conservation and Recreation (DCR) Office of Dam Safety requires biennial inspections on both the Stony Brook and Hobbs Brook Reservoir dams by registered professional civil engineers.  Both dams are characterized as "Large", "High" hazard potential dams in "Satisfactory" condition with no evidence of immediate instability. Watershed Division staff regularly inspect dams for seepage, rodent burrows, and other maintenance-triggering cues and generate in-house summary reports.  

Security and Enforcement

Two full time Reservoir Caretakers provide seven-day-a-week coverage for watershed-wide surveillance, security, facilities maintenance, and assistance with implementing the Source Water Protection Program. Activities that the Watershed Division has not been notified of through regulatory processes or partnerships are usually discovered by the caretakers during routine patrols. The Cambridge Water Department also employs two Rangers who educate visitors at Fresh Pond Reservation about the importance of protecting the water supply and enforce Fresh Pond Rules and Regulations.