Gatun Lake forms a major component of the Panama Canal; the lake, including the flooded arm extending up the Chagres River, makes up 32.7 km (20.3 mi) of the raised part of the waterway, the other part being the 12.6 km (7.83 mi) Culebra Cut.

The canal follows a clearly marked route around the lake's islands, following the deeper water south from Gatun Locks, and then east.
A small "shortcut" channel, the "Banana Cut", runs between the islands, providing a slightly shorter route through the lake; this is used by canal launches and yachts to cut a little time off the crossing and to avoid the heavy ship traffic.

The lake is also important as a reservoir of water for the operation of the canal locks.
Each time a ship transits the canal, 202,000 m³ (53,400,000 US gal) of water is passed from the lake into the sea; with over 14,000 vessel transits per year, this represents a very large demand for water.
 Since rainfall is seasonal in Panama, the lake acts as a water store, allowing the canal to continue operation through the dry season.

A major factor in water regulation is the ability of the rainforest in the lake's watershed to absorb rainfall, releasing it gradually into the lake.
However, significant deforestation of the watershed has cleared away much of the vegetation and reduced the area's water capacity.
This has resulted in falling water levels in the lake during the dry season.
Coupled with the massive increase in canal traffic since its opening, and the resultant increase in water usage, this is an ongoing problem for the canal (see Panama Canal: Water issues).
Gatun Lake forms a major component of the Panama Canal; the lake, including the flooded arm extending up the Chagres River, makes up 32.7 km (20.3 mi) of the raised part of the waterway, the other part being the 12.6 km (7.83 mi) Culebra Cut.
The canal follows a clearly marked route around the lake's islands, following the deeper water south from Gatun Locks, and then east. A small "shortcut" channel, the "Banana Cut", runs between the islands, providing a slightly shorter route through the lake; this is used by canal launches and yachts to cut a little time off the crossing and to avoid the heavy ship traffic.
The lake is also important as a reservoir of water for the operation of the canal locks. Each time a ship transits the canal, 202,000 m³ (53,400,000 US gal) of water is passed from the lake into the sea; with over 14,000 vessel transits per year, this represents a very large demand for water.  Since rainfall is seasonal in Panama, the lake acts as a water store, allowing the canal to continue operation through the dry season.
A major factor in water regulation is the ability of the rainforest in the lake's watershed to absorb rainfall, releasing it gradually into the lake. However, significant deforestation of the watershed has cleared away much of the vegetation and reduced the area's water capacity. This has resulted in falling water levels in the lake during the dry season. Coupled with the massive increase in canal traffic since its opening, and the resultant increase in water usage, this is an ongoing problem for the canal (see Panama Canal: Water issues).
Gatun Lake