Gatun Lake: the Panama Canal operating reservoir

Gatun Lake is the artificial freshwater lake that forms the summit reach of the Panama Canal, sitting 26 m above sea level in the valley of the Chagres River and covering about 422 km2. Its level is the operational variable that sets the maximum authorized transit draft: the Panama Canal Authority’s published limits of 12.04 m and 15.24 m tropical fresh water apply only at lake levels of 24.01 m and 25.91 m respectively.

The full article will cover the lake’s operating band between 24.8 m and 26.7 m, the deepening that raised active storage from 770 to 1,420 million cubic metres, the annual water balance of inflow, evaporation, lockage and spillway, salinity management in the navigation channel, and the competition between navigation, hydropower and municipal supply for the same water. Roughly 95 percent of the drinking water for Colon, Panama City and San Miguelito comes from the same watershed.