How do activities in the watershed affect the Ipswich River?
Activities in the watershed affect the Ipswich River in several ways. During rainstorms, pollutants wash into the river from roadways and parking lots, construction sites, lawns, landfills and other “non point” sources. Clearing land not only exposes soil to erosive forces, but also results in changes to the “water cycle,” affecting flows in the river (See water cycle diagram). When land is paved or covered with buildings or other “impervious” or hard surfaces, the ground cannot absorb water from rain or snow. Instead, the water flows off the ground as “runoff.” This situation can result in higher peak flows during storm events. (See graph of effect of urbanization). At the same time, less water is stored in the ground. This “groundwater” is what provides continuous flow in a river even when it is not raining. So decreasing groundwater results in less flow in the river during low-flow periods. Other activities which affect the Ipswich River are water withdrawals for human use, and the
