The Honey Brook basin as defined here is located between Welsh Mountain and the Baron Hills and serves as the headwaters region for the East and West Branches of Brandywine Creek, the South Branch of French Creek, and Pequea Creek with Brandywine Creek flowing to the Delaware River, French Creek to the Schuylkill River, and Pequea Creek to the Susquehanna River. This entry focuses on the drainage divide between South Branch French Creek and East Branch Brandywine Creek, although West Branch Brandywine Creek originates in the same lowland a short distance west of East Branch Brandywine Creek headwaters and the Pequea Creek headwaters are located a short distance west of West Branch Brandywine Creek headwaters.

Figure 1: Drainage divide area between South Branch French Creek and East Branch Brandywine Creek. United States Geological Survey map digitally presented using National Geographic TOPO software. 

Figure 1 illustrates the location of the drainage divide between South Branch French Creek and East Branch Brandywine Creek. The South Branch French Creek originates in the north center area of figure 1 and then flows in a northeast and east direction to the northeast corner of figure 1. East of figure 1 the South Branch French Creek flows in an east and northeast direction to join southeast and east oriented French Creek, which flows to join the southeast oriented Schuylkill River at Phoenixville.

Welsh Mountain can be seen in the map northwest corner and continues west of figure 1 in a southwest direction. The East Branch of Brandywine Creek originates in the two largest lakes (reservoirs) south of Welsh Mountain with separate headwaters streams diverging until converging where the southern words WEST NANTMEAL are located and East Branch Brandywine Creek then flows in an east and southeast direction to the figure 1 south edge (near southeast corner). South of figure 1 East Branch Brandywine Creek flows in a southeast and south direction to cross the Chester Valley and then in a south-southeast direction to join West Branch Brandywine Creek and to form south oriented Brandywine Creek, which joins the Delaware River at Wilmington, Delaware.

The Baron Hills are south of figure 1 and have an east-west orientation. Elevations on Welsh Mountain exceed 900 feet and in places exceed 1000 feet while some Baron Hills elevations exceed 800 feet and in places exceed 900 feet. The Honey Brook basin is the lower region between Welsh Mountain and the Baron Hills. The drainage divide between South Branch French Creek headwaters and East Branch Brandywine Creek headwaters seen in figure 1 has an elevation of between 640 and 660 feet at two separate points. West Branch Brandywine Creek headwaters are located just west of figure 1 and the lowest point on that drainage divide is approximately 660 feet. A short distance further west are Pequea Creek headwaters and the lowest point on the drainage divide between West Branch Brandywine Creek and Pequea Creek is between 700 and 720 feet.

The low drainage divides between Welsh Mountain and the Baron Hills linking the Schuylkill River (South Branch French Creek), the Delaware River (East and West Branches Brandywine Creek), and the Susquehanna River (Pequea Creek) were eroded by massive and prolonged southwest oriented flood flow moving from north and east of the present day Schuylkill River valley to what at that time was the actively eroding Susquehanna River valley. Headward erosion of the southwest oriented Pequea Creek drainage basin across what is today the southern half of the Conestoga Valley lowered the area between Welsh Mountain and the Baron Hills. Headward erosion of the south oriented Brandywine Creek West and East Branch valleys captured the southwest oriented floodwaters and diverted the flow from the Pequea Creek route to what at that time was a newly eroded Delaware River valley. Shortly thereafter (in terms of regional erosion) headward erosion of the southeast oriented French Creek valley (from the actively eroding Schuylkill River valley) beheaded and reversed the flood flow to create the present day east and northeast oriented South Branch French Creek drainage route.