Issues
How Development Affects Water

In the Ipswich River Watershed, groundwater and surface water are closely connected. Groundwater flows into the Ipswich River, and keeps the river flowing when it is not raining - this is called baseflow. Pumping groundwater aquifers via wells can interrupt this flow into the river, resulting in lower flows or even no flow in the Ipswich River.

The Ipswich River’s water “deficit” is caused by a combination of factors:

• Excessive water withdrawals. Several municipalities rely on streamside groundwater wells in the Ipswich River watershed for their water supplies. During the summer, when the river is naturally running low due to higher rates of evapotranspiration, water demand increases as suburban residents water lawns and fill swimming pools. The amount of water pumped in the summer is often twice the year-round average. Studies show that the amount of water needed to restore natural flows – an estimated 14.4 million gallons per day – is about equal to the estimated amount used for lawn watering.

• Increased impervious surface that reduces natural aquifer recharge. The hydrologic cycle of the watershed has changed as forested lands, which percolate rainwater into the ground, are converted to paved roads and developments, which tend to flush rainwater away during storms. This runoff can also become polluted with contaminants like motor oils and greases, pestices and herbicides, and animal waste, leading to nonpoint source pollution.

• Wastewater export from the basin. 80 percent of the water pumped from the watershed is ultimately exported via sewer systems that discharge treated wastewater outside of the watershed. Additional clean groundwater infiltrates into sewer lines and is also exported.