FAQs

 Every Year the Water Board fills Wenham Lake from its other sources, (Ipswich River Canal and the Putnamville and Longham Reservoirs), to its overflow elevation by the end of May. The Board pumps and treats the water from Wenham Lake at its filtration plant throughout the summer months. At the end of the summer, when the lake has a low surface elevation, the Board can then perform its vegetation maintenance around the shoreline of the lake and clean its backwash water lagoon at the plant. This necessary maintenance work can only take place when the lake has a low water surface elevation. Once this work is completed, which is typically in September each year, the Board then refills Wenham Lake from its other sources, mostly from the Putnamville Reservoir. Once the lake is full, which is typically by the beginning of December each year, the Board then refills the Putnamville Reservoir from the Ipswich River Canal until it is full, which is typically by May each year. This cycle repeats every year, and the use of supply sources varies depending on the available water resources.    

You can read more about our reservoir interconnections on our “Our Water” page.