2. Methods
In this section, we provide an overview of the study area, conceptual
and empirical models, and methods used in research.
2.1. Study area
The study area is the Ipswich River watershed (Fig. 1). The Ipswich
River Watershed is located in northeastern Massachusetts
and flows from its headwaters in Burlington, Wilmington and Andover,
until reaching Plum Island Sound of the Atlantic Ocean in the
town of Ipswich (Fig. 1). The river meanders and has a relatively
flat course especially toward the end of the reach as it approaches
the Ipswich Bay area. From the Ipswich headwater to the river’s
mouth, the elevation change is only about 35 m over about
64.37 km and has a drainage area of 401.45 square kilometers.
The river itself is 56 km long and with its 45 tributaries, it covers