Protecting Pennichuck
Water Supply with a Clean Sweep

Water supply quality is one of the top concerns for the environment as a whole as well as for individual communities like the ones serviced by The Pennichuck Brook Watershed. Pennichuck, which provides drinking water to the greater Nashua, New Hampshire area is, like many water supplies, facing the effects of developed land. They are now addressing the issues of drainage basins, stormwater management, and runoff to improve water quality.

What is Polluting Pennichuck?

A surprising source of contaminants comes from the lack of maintenance to commercial and private parking lots and driveways. While surrounding communities do regular sweeps of roadways and major streets, these smaller areas are infrequently swept and significantly contribute to water pollution. Sweeping along with regular catch basin cleaning and stormwater management has been shown to effectively remove phosphorus and sediment from watersheds.

How often are Sweeps and Catch Basin Cleaning Performed?

The Pennichuck Catch Basin Cleaning Feasibility report found that many businesses do not perform regular sweeps, do them ineffectively with push brooms or only have them done once a year after the snow melts. Drainage basin cleanings are also only done on an as-needed basis. The report found that with regular adherence to watershed maintenance there would be the significant reduction in total suspended solids (TSS) in the stormwater runoff.

How Much Would These Measures Reduce Contaminants?

A parking lot maintenance program combined with catch basin cleaning would contribute a total phosphorus and TSS reduction of 147 lbs/yr., a significant portion of the total goal of 2,258 lbs/yr. It is Important to note that it was also found that hiring outside companies was more cost effective than purchasing and maintaining equipment by the city. Additionally, having a city run program would ensure a higher level of participation by businesses.