Downstream Effects of the Levee Overtopping at Wilkes-Barre, Pennsylvania During Tropical Storm Agnes

摘要

A rainfall-runoff model for Tropical Storm Agnes in the Susquehanna River Basin was developed. A reservoir operation model was also developed in order to compute regulated streamflows. Susquehanna River flood discharges were computed for Wilkes-Barre, PA, for both levee nonovertopping and levee overtopping conditions. The levee overtopping conditions were modeled using storage-outflow relations developed from water surface profiles for the Wilkes-Barre reach. If the levee had been sufficiently high to contain the flow, the peak discharge would have been increased and occurred earlier. Translating this earlier and larger peak downstream would have resulted in practically a 10 percent increase in the peak discharge at Sunbury. This large peak is due to both the increased peak at Wilkes-Barre and coincident timing with the peak coming from the West Branch of the Susquehanna River. Since the actual peak flow at Sunbury was within inches of the top-of-the-levee, a potentially disasterous flood could have occurred at Sunbury if the Wilkes-Barre levee had not been overtopped. (Author)