Friday, February 15, 2013

Geography of Guyana

The Geography of Guyana comprises the physical characteristics of the country in Northern South Americaand part of Caribbean South America, bordering the North Atlantic Ocean, between Suriname and Venezuela,  With a 430-kilometre Atlantic coastline on the northeast, Guyana is bounded by Venezuela on the west, Brazil on the west and south, and Suriname on the east. The land comprises three main geographical zones: the coastal plain, the white sand belt, and the interior highlands.
A line of swamps forms a barrier between the white sandy hills of the interior and the coastal plain. These swamps, formed when water was prevented from flowing onto coastal croplands by a series of dams, serve as reservoirs during periods of drought.

The white sand belt lies south of the coastal zone. This area is 150 to 250 kilometers wide and consists of low sandy hills interspersed with rocky outcroppings. The white sands support a dense hardwood forest. These sands cannot support crops, and if the trees are removed erosion is rapid and severe. Most of Guyana's reserves of bauxite, gold, and diamonds are found in this region.

The largest of Guyana's three geographical regions is the interior highlands, a series of plateaus, flat-topped mountains, and savannahs that extend from the white sand belt to the country's southern borders. The Pacaraima Mountains dominate the western part of the interior highlands. In this region are found some of the oldest sedimentary rocks in the Western Hemisphere. Mount Roraima, on the Venezuelan border, is part of the Pakaraima range and, at 2,762 meters, is Guyana's tallest peak. Farther south lies the Kaieteur Plateau, a broad, rocky area about 600 meters in elevation; the 1,000-meter high Kanuku Mountains; and the low Acarai Mountains situated on the southern border with Brazil.

Much of the interior highlands consist of grassland. The largest expanse of grassland, the Rupununi Savannah, covers about 15,000 square kilometers in southern Guyana. This savannah also extends far into Venezuela and Brazil. The part in Guyana is split into northern and southern regions by the Kanuku Mountains. The sparse grasses of the savannah in general support only grazing, although Amerindian groups cultivate a few areas along the Rupununi River and in the foothills of the Kanuku Mountains.
Map of the Essequibo drainage basin
Guyana is a water-rich country. Numerous rivers flow into the Atlantic Ocean, generally in a northward direction. A number of rivers in the western part of the country, however, flow eastward into the Essequibo River, draining the Kaieteur Plateau. The Essequibo, the country's major river, runs from the Brazilian border in the south to a wide delta west of Georgetown. The rivers of eastern Guyana cut across the coastal zone, making east-west travel difficult, but they also provide limited water access to the interior.

Waterfalls generally limit water transport to the lower reaches of each river. Some of the waterfalls are spectacular; for example, Kaieteur Falls on the Potaro River drops 251 metres, more than four times the height of Niagara Falls. Other enormous waterfalls are King Edward VIII Falls (256 m), Kumerau Falls (190 m), Oshi Falls (160 – 210 m). In the country are known to exist more than 200 rapids and more than 70 large waterfalls. Many waterfalls are little known and most are not measured yet, it is possible that there are waterfalls in excess of 300 m tall.
Category:Rivers of Guyana, Category:Waterfalls of Guyana.

Drainage throughout most of Guyana is poor and river flow sluggish because the average gradient of the main rivers is only one meter every five kilometers. Swamps and areas of periodic flooding are found in all but the mountainous regions, and all new land projects require extensive drainage networks before they are suitable for agricultural use. The average square kilometer on a sugar plantation, for example, has six kilometers of irrigation canals, eighteen kilometers of large drains, and eighteen kilometers of small drains. These canals occupy nearly one-eighth of the surface area of the average sugarcane field. Some of the larger estates have more than 550 kilometers of canals; Guyana itself has a total of more than 8,000 kilometers. Even Georgetown is below sea level and must depend on dikes for protection from the Demerara River and the Atlantic Ocean.