Map of Panama Canal

Because of the configuration of the Isthmus of Panama, the canal runs northwest-southeast from the city of Colon to Panama City. In between are the blue waters of Gatun Lake and the dark green forests on either side of the canal. The Canal Zone extends approximately 8 km on either side of the shipping channel, except near Madden Lake (east of the canal near its center). The shipping channel of the canal is 82 km long, though the Canal Zone is only 64 km long. The canal zigzags across the isthmus to take advantage of the geographic features of the area, such as the Chagres River. The controlled water supply for the canal is provided by the three artificial lakes: Gatun near the city of Colon terminus, Miraflores near the Panama City terminus, and Madden Lake. Gatun is the largest of the three lakes, covering 429 km². Madden Lake was built as a large supplemental reservoir to keep water levels up in the canal during the dry season. All three lakes are vital sources for maintaining the ship channel over the Continental Divide (Gaillard Cut) and for regulating the flow of water that enables huge vessels to be lifted and lowered in the massive locks.

A concern to scientists and environmentalists is to keep the forests bordering the canal on both sides in place to help lessen soil erosion and sedimentation. Excessive soil erosion and sedimentation caused by deforesting the zone could lead to serious silting problems, which could eventually close the canal. This would have profound economic effects on both Panama and the countries of the world that use the canal (source: NASA).