Gatun Lake
| Gatun Lake | |
|---|---|
| Coordinates | 9°11′23″N 79°53′15″W / 9.18972°N 79.88750°W |
| Type | artificial lake |
| Primary inflows | Chagres River |
| Basin countries | Panama |
| Surface area | 425 km² |
| Surface elevation | 26 m |
| Islands | Barro Colorado Island |
Gatun Lake (Sp. Lago Gatún) is a large artificial lake situated in the Republic of Panama; it forms a major part of the Panama Canal, carrying ships for 33 km (20 miles) of their transit across the Isthmus of Panama.
The lake was created between 1907 and 1913 by the building of the Gatun Dam across the Chagres River. At the time it was created, Gatun Lake was the largest man-made lake in the world, and the dam was the largest earth dam.
Description
The lake is situated in the valley of the Chagres River. It was formed, and the river widened and deepened, by the construction of the Gatun Dam about 10 km (6 miles) from the river's mouth in the Caribbean Sea in 1907–1913. The geography of the area was ideal for the creation of a large lake here; the hills bordering the valley of the Chagres open up widely around the area of the lake, but come together to form a gap just over 2 km (1.4 miles) wide at the location of the dam. The damming of the river flooded the originally wooded valley; almost a century later, the stumps of old mahogany trees can still be seen rising from the water, and submerged snags form a hazard for any small vessels that wander off the marked channels.
Gatun Lake has an area of 425 km² (164 square miles) at its normal level of 26 m (85 ft) above sea level; it stores 5.2 cubic kilometres (183,000,000,000 ft³) of water, which is about as much as the Chagres River brings down in an average year.
With the creation of the lake many hilltops became islands. The biggest and best known of them is Barro Colorado Island, home of the world famous Smithsonian Tropical Research Institute (STRI).
The lake has given its name to the Gatun structure, which may be an eroded impact crater.
Role in the canal
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 miles) of the raised part of the waterway, the other part being the 12.6 km (7.8 mile) Gaillard 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 million U.S. gallons) 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).
ANGLING IN GATUN LAKE
Approximately 200 square miles of unspoiled natural tropical rain forest area, Gatun Lake has been protected in its natural state for over 100 years. Various extraordinary tropical plants, trees, insects and animals are found here in their characteristic ambiance. Many elusive reptile, bird and mammal species can be observed along the countless shores and amid the tropical rain forest. Rare toucans, aquatic bird species, assorted parrot varieties, herons and egrets, hawks and snail kites will fascinate bird enthusiasts. Unusually encountered jungle creatures are frequently discovered interacting naturally in their pristine habitat. White faced and howler monkeys, saddleback anteaters and three toed sloths are just some of the rain forest animals you might notice while you are exploring Gatun Lake.
Since the worldwide availability of this class of extraordinary environment is extremely remote and rare, many notable scientific organizations such as the Smithsonian Institution have determined it a vital area to conduct many critical ground-breaking scientific tropical studies throughout the years. The Smithsonian Institution in fact operates one of the largest, most complete tropical research facilities on earth at Barro Colorado, the largest island in Gatun Lake. Scientists from all over the world come to Panama to perform technical research regarding the flora and fauna throughout the Gatun Lake region.
Besides its status as a biological preserve, Gatun Lake is an excellent environment for many tropical game fish species. Chief among these is the Peacock Bass (Cichla Monoculus) locally known as ‘Sargento. Peacock Bass or ‘Sargento’, are not a native game fish of Panama but originate from the Amazon, Rio Negro and Orinoco river basins of South America where they are called Tucanare or Pavon and are considered a premier sport fishing quarry. There are over 16 species of Peacock Bass, all highly regarded in freshwater sport fishing, five of which are recognized scientifically as valid. Among these valid species is the ‘Cichla Monoculus’ variety of Peacock Bass, which has been utilized extensively in the freshwater aquarium trade since World War II and is among the top sport fishing Peacock Bass. It is suspected that this species was introduced into some freshwater lakes and rivers of Panama by accident as early as 1958 initiating hitherto unknown sport fishing opportunities. Since then they have proliferated at an astounding rate and have virtually taken over to become the dominant angling game fish species in Gatun Lake of the Panama Canal. Peacock Bass are not really a bass but a South American Cichlid species very similar to Perch. While they are ambush predators they are also sight feeders and will chase prey down from quite a distance especially in the clear waters of Gatun Lake. They are naturally aggressive and display a mean spirited disposition toward attractor type flies which they heartily attack. An accomplished fly fisher with or a veteran angler can quite handily catch thirty to forty average sized Peacock Bass at Lake Gatun on a typical day. Early morning and late afternoon seem to be the best times to fool big bass. These larger, over-developed Peacock Bass are instinctively suspicious and clever. They are correspondingly more difficult to deceive and proportionally far stronger once hooked than their younger brethren, consequently more skill and shrewdness is required on the part of the angler to catch them. Since Peacock Bass don’t feed at night they are terribly hungry at first light and again as darkness approaches they become frantic for food. Because of the low light conditions and looming hunger pangs they are more apt to be deceived with a well presented fly at these times. The clear water of Lake Gatun magnifies the fly therefore offerings should be smaller and precisely tied to induce the spectacular strikes of the 5 to 10 pound trophy behemoths. Dexterous and practiced rod handling techniques are essential to catching one of these tough elusive whoppers as Gatun Lake is fraught with submerged line snagging structure and the enterprising jumbo bass will cut you off if given the slightest chance. An experienced Panama fishing guide will advise that lifelike baitfish imitations and precise shrimp patterns as well as gaudy surface attractors are essential weapons for combat with these tropical freshwater apex predators.
While fly fishing or angling in Panama there are several other wonderful tropical game fish likely to be encountered in Gatun Lake. Various species of snook , most notably the Common snook, Centropomus undecimalis have entered Gatun Lake through the Locks and make a fantastic angling quarry. Also Tarpon are year around residents in the lake and are the premier big game angling quarry. Fly patterns, color and actions vary not only seasonally but frequently from day to day, involving a precious measure of experience and perseverance to determine. Subsequent obstacles to overcome include successful hooking of the tarpon or snook and then the actual aerial and submarine combat that ensues. Jaguar Guapote, a beautiful aquarium species transplanted into Gatun Lake from the Atlantic mountain slopes of Nicaragua, are often caught while fly casting for Peacock Bass. Not as colorful as the Peacock Bass they are somewhat similar in shape and manner. Reaching a maximum size of about five pounds Jaguar Guapote are an excellent game fish that will readily take the same flies as the Peacock Bass. Scrappy and determined fighters these gourmet delicacies are much sought after by deep fried afflicted anglers. Caution is advised when removing the fly from freshly caught specimens as they possess an impressive set of choppers.
Additionally there are two interesting tropical Pan Fish varieties of game fish abundant in Gatun Lake. These include the famous Oscar, a stunning aquarium prize released in the Lake over 10 years ago. Also a South American Cichlid species they have proliferated along with their cousins the Peacock Bass and on occasion are found by unsuspecting fly fishermen in hostile hordes. A Fly fishing guide favorite, Oscars are pound for pound probably one of the strongest freshwater game fish a fly fisher will battle in the tropics. Averaging about one to two pounds they are strictly ambush predators and are even more difficult than the larger Peacock Bass to seduce with a fly. Imitative patterns of natural prey are vital and presentation of the fly must be near perfect to induce a strike.
The only other more formidable game fish in Gatun Lake would be the Tropical Bluegill or Vieja as they are known locally. These indigenous game fish are perhaps trickier to land on a fly than an 8 pound brown trout on a small fast running Montana mountain stream. They represent a true milestone for the dedicated tropical freshwater fly fisher. Possibly more cherished by Panama fly fishing guides than a trophy Peacock Bass, the Vieja is unbelievably troublesome to deceive with fly or even live bait. In fact, well tied and expertly presented flies probably account for far more sport caught Viejas than any other method. Once hooked these bulldog gamesters are the devil to get in the boat! Viejas are super strong and grow to about 8 pounds hence they are invulnerable to all but the most accomplished master fly rodders!
References
- History Of The Panama Canal, by Ira E. Bennett
- The Panama Canal, by Colonel George W. Goethals