Town of Billerica, Massachusetts 

Ambient Engineering (Ambient) was retained by the Town of Billerica Engineering Department to evaluate drainage problems in the Michael Road neighborhood in north Billerica that floods during heavy rains each spring. Persistent flooding had resulted in frequent wet basements, road closures and roadway deterioration, necessitating repaving as frequently as every two years. Ambient’s efforts have included the following:

• collecting record and field data on the existing topography, roadways, development, drainage, and stormwater management systems in place;
• identifying and developing a GIS-based AutoCAD model of the 157 acre watershed (shown right);
• developing a HydoCAD model to evaluate the infiltration, storage and conveyance capacity within the watershed during varying storm events;
• evaluating and recommending improvements to the stormwater management system;

Ambient recommended enlarging sections of the existing stormwater collection system, replacing the outlet structure (see photo below) of the largest of four detention ponds at the upstream end of the watershed, and making improvements to increase infiltration and reduce stormwater volume. The latter include rebuilding Michael Road with drainage swales on both sides to replace catch basins, installing rain gardens in the middle of currently paved cul-de-sacs and working with area residents to increase infiltration on private properties. Ambient worked with the Billerica Engineering Department to secure Chapter 90 funding for the project as well as develop an estimate for a Town meeting warrant article.

The Town of Billerica has also retained Ambient to present the study of the findings to the Michael Road community and prepare bid specifications and drawings for spring 2006 construction.