CEI and Yarmouth recently undertook a two-phase project to improve water quality within the pond. An existing saltwater pond previously had relatively good flushing action during routine tide events, however, over the last 5 or 10 years, the outlet path has become increasingly silted in due to routine wave action and the ever-changing nature of coastlines. While the pond used to have tidal exchange on a daily basis, it now only occurs during extremely high spring-tide events which has led to decreased water quality and has largely been converted to a freshwater pond. Exacerbating problems in this pond is that two untreated stormwater discharges contributed pollutant loading to this waterbody. Both the lack of flushing and degraded water quality has led to complaints by local residents, such as unpleasant odors in the summer months.
Phase I has already been completed, and included the installation of a stormwater BMP at Bay View Pond, as well as alleviating both untreated stormwater discharges to the pond by treating stormwater either through a subsurface gravel wetland or infiltrating small events into a subsurface leaching system. The BMP consists of a hybrid bioretention area and gravel wetland to aid in the removal of bacteria and nitrogen from stormwater runoff. This project now provides stormwater treatment to two previously untreated discharges to the nearby pond. CEI’s work included site survey, completing conceptual and final design, project permitting, development of technical specifications, construction oversite, and development of as-built plans.
Phase II is expected to commence during 2021 and will consist of installation of a new culvert to improve flushing in the pond.