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Flood Studies - Northeast
Pennsylvania, Maryland, and West Virginia
Preparation of flood studies in the Northeast, which include flooding sources in Virginia, West Virginia, Maryland, Delaware, Pennsylvania, and Washington, D.C. The scope of these flood studies was to perform hydrologic and hydraulic analyses to revise existing (effective) Flood Insurance Rate Maps (FIRM), in part as a result of implementation of mitigation projects such as improved channels, levees, floodwalls, and other flood control projects. Examples of projects are briefly described.
Flood Study, Borough of McConnelsburg (Fulton County), PA. There was no Flood Insurance Rate Map (FIRM) for this community for floodplain management use. The Special Flood Hazard Area (SFHA) along Big Cove Creek within the corporate limits had not been mapped by FEMA. Big Cove Creek flows in the urban downtown area where property was located in the floodplain. Hydrologic analysis was performed using the USGS regression equations. The urban peak discharges were computed using the USGS water-supply paper 2207. Hydraulic analyses were performed using HEC-RAS model. Cross-sections of the channel and adequate distance of the floodplain area were surveyed. The extents of the cross-sections were determined using approximate hydraulic analysis. This resulted in cost saving in the surveying work. The 10-, 25-, 50-, and 100-year flood profiles were computed and the 100-year floodplain was mapped and delineated. Observed high water marks were used in the calibration of the model and the verification of the delineated floodplain boundary.
Photo above - Big Cove Creek flows in the urban downtown of McConnelsburg. The showroom of this car dealer was on Cove Creek left overbank. The dealer stated that several cars have been swept away during a previous flood event.
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