Weymouth - Sewer Model

Comprehensive Sewer System Assessment
Weymouth, Massachusetts

Overview

Environmental Partners conducted a comprehensive evaluation of Weymouth’s sewer system with the intent to identify potential infrastructure upgrades and improvements needed for the Weymouth sewer system to accept an additional 1 MGD flow from the Southfield Development at the former Weymouth Naval Air Station. This evaluation included the construction of a state-of-the-art sewer system model (using SewerCAD), calibration of the model by flow metering, and development and identification of feasible alternatives for accepting Southfield wastewater flows.

Approach

Weymouth’s sewer system consists of nearly 175 miles of gravity sewer pipe, almost 6000 sewer manholes, and 30 pump stations. The sewer system pipe sizes range from 6-inch to 42-inch in diameter. The majority of the system was built between 1947 and 1980.

The Town’s GIS information data base was used to prepare the SewerCAD pipe and manhole network. Water meter records were used to create the sewer loading parameters. Thirty-nine flow meters were strategically placed in manholes throughout the system. After eight weeks of metering, the data collected was converted to infiltration and inflow values and assigned in the model.

At the conclusion of the study, the Town retained an interactive hydraulic model of the sewer system. The model was used to evaluate the performance of the system considering the future projected loading from the Southfield development under different scenarios. Environmental Partners used this tool to develop detailed recommendations for system upgrades as required.

All our findings were used to prepare an engineering report that includes the results, conclusions, recommendations, cost estimates, and implementation schedule for the proposed improvements.