What is Summer Low Flow?
In summer, our rivers and streams typically experience their lowest annual flow levels, and are most vulnerable to damage from water withdrawals. Water use in many residential communities in Massachusetts often doubles or triples during the summer months. Most of this additional water is used for irrigating lawns at homes and businesses. The water used for irrigation often comes directly or indirectly from rivers and streams, and reduces summer flow. Smaller rivers and streams may naturally experience periodic low flows in summer, and high water withdrawals from wells and reservoirs can further diminish flow and has caused some to dry up more frequently than in the past.
High summer water use has serious environmental impacts and fiscal ramifications, and can sometimes present a human health and safety concern. In some situations, if too much water is used all at once, the water in storage tanks may drop to levels where insufficient water volume and pressure is available to provide adequate water in the event of a fire.
There are three major factors that have, alone or in combination, greatly altered the natural water regime, or hydrology, of our rivers and streams. These are: