Panama – Flood Inundation Mapping of the Chagres River

Alhajuela Lake and Madden Dam on Panama’s Chagres River play an integral role in operating and managing the Panama Canal. Large spills from the Madden Dam may threaten the lives and property of people living along the Chagres River downstream. Under contract to the U.S. National Weather Service (NWS), Riverside Technology, inc. (RTi) developed a project to determine the impacts of various releases from Madden Dam on downstream water levels, including

Río Chagres Flood Inundation Map

a release resulting from a sudden catastrophic failure of the dam. Special emphasis was given to the areas close to the main Transisthmian Road and the Panamanian towns of Guayabalito, Santa Rosa, and Gamboa.

RTi selected NWS’s dynamic routing program FLDWAV to analyze the releases from Madden Dam, and the Panama Canal Authority (PCA) provided cross section information. Steady-state flow routing was simulated for nine release scenarios from Madden Dam, ranging from a relatively small 50,000 cfs (1416 cms), to a massive 262,000 cfs (7419 cms), and a dam break. RTi then used ARC/INFO to map the peak stages at each cross section, and to portray an inundation surface for each of the steady state releases, and the dam failure scenario. The PCA uses these maps as a guideline to warn or evacuate threatened areas should conditions in the watershed require large releases from Madden Dam.

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phone: (970) 484–7573  fax: (970) 484–7593 www.riverside.com