The East Branch Chester Creek is located slightly east of West Chester and originates in the Valley Hills north of West Chester before flowing in a south-southeast direction with a jog to the east at West Chester Reservoir to eventually join the West Branch Chester Creek (which originates south of West Chester) to form southeast oriented Chester Creek, which then flows to the southwest oriented Delaware River. The East Branch Brandywine Creek originates north of the Chester Valley, which is north of the Valley Hills, and flows in a south and southeast direction across the Chester Valley and the Valley Hills and then west of West Chester to join the West Branch Brandywine Creek to form southeast oriented Brandywine Creek, which also flows to the southwest oriented Delaware River. Figure 1 illustrates the East Branch Chester Creek-East Branch Brandywine Creek drainage divide area north of West Chester and south of the Valley Hills.
Figure 1: East Branch Brandywine Creek-East Branch Chester Creek drainage divide area located north of West Chester, PA and south of the Valley Hills. See text below for detailed description. United States Geological Survey map digitally presented using National Geographic TOPO software.
The East Branch Brandywine Creek can be seen meandering in a southeast direction across the southeast corner of figure 1. Taylor Run is a tributary originating near location 1 and flowing in a south and then southwest direction to join the East Branch Brandywine Creek near the southwest corner of figure 1. The East Branch Chester Creek can be seen flowing in a south-southeast direction to West Chester Reservoir near the northeast corner of figure 1 and flows through location 2. Note how just west of the West Chester Reservoir, headwaters of four separate Taylor Run tributaries are located near the East Branch Chester Creek valley and the lack of East Branch Chester Creek tributaries from the west. The East Branch Chester Creek-East Branch Brandywine Creek drainage divide, seen in figure 1 is an asymmetrical drainage divide, where tributaries flowing to the East Branch Brandywine Creek originate near the East Branch Chester Creek valley.
Note how the four different Taylor Run tributaries originate along the East Branch Chester Creek-Taylor Run drainage divide and how shallow saddles are notched into the East Branch Chester Creek-Taylor Run drainage divide. Each of those saddles is evidence of a former southwest oriented flow channel supplying water to the Taylor Run valley prior to headward erosion of the deeper East Branch Chester Creek valley. The asymmetrical drainage divide, the four converging tributaries, and the shallow saddles suggest headward erosion of the East Chest Creek valley captured (or beheaded) southwest oriented flood flow to the Taylor Run valley. The flood flow was moving in closely spaced diverging and converging channels that had been captured by headward erosion of the southwest oriented Taylor Run valley, which had eroded headward from what was probably a newly eroded East Branch Brandywine Creek valley. Headward erosion of the deeper East Branch Chester Creek valley captured the flood flow and diverted the floodwaters to the Chester Creek valley.