Moving Beyond a Plan - Precision Modeling in Boston, MA

The Boston Water and Sewer Commission (Commission or BWSC) is updating its collection system model to reflect recent improvements in the collections system. The hydraulic conditions simulated by these models will be used eventually by the Commission’s design and operational staff. The overall goal is to make these models reflect real world conditions. When using a model to support sewer design and/or to make operational decisions, the expectations for the model’s accuracy are greater than for a planning model. Model calibration will increase the accuracy of the model. However, an accurate representation of the various hydrologic features across the model is also necessary and care should be taken that parameters are adjusted within reasonable ranges. Selecting the appropriate parameters to adjust during the calibration is critical. This paper will illustrate the techniques used to update the sewer model for the Boston Water and Sewer Commission. These techniques include comparing model parameters to data such as water consumption information, reviewing seasonal trends, and regional inflow characteristics.