Lake Maracaibo

Lake Maracaibo (Spanish: Lago de Maracaibo) is located in northwestern Venezuela, between the states of Zulia, Trujillo, and Mérida. While Maracaibo is commonly referred to as a lake, its current hydrological characteristics may better classify it as estuary and/or semi-enclosed bay connected to the Gulf of Venezuela. With a surface area of 13,512 km² (5,217 sq mi), if counted as a lake it would be the largest in South America, ahead of Lake Titicaca, as well as one of the oldest lakes on Earth, having formed 36 million years ago in the Andes Mountains.

The lake consists of brackish water, and is connected to the Gulf of Venezuela to the north by a narrow strait. It is fed by numerous rivers, the biggest being the Catatumbo River. The fault in the northern section has collapsed and is rich in oil and gas resources. It is Venezuela's main oil producing area and an important fishing and agricultural producing area. Eutrophication caused by oil pollution is a major environmental problem facing the lagoon. The area around the lagoon is inhabited by a quarter of the country's population and is also the place with the most frequent lightning on Earth. The famous Catatumbo lightning can illuminate nighttime navigation.

Lake Maracaibo is located within the eponymous basin and is one of the oldest lakes on earth. It was formed 36 million years ago when the faults collapsed when the Andes were uplifted in the late Eocene. In the geological history, sea water and fresh water have alternated many times, and have flooded the area. At the end of the last glacial period, the sea level rose, connecting Lake Maracaibo directly with the Atlantic Ocean, and the lighter fresh water floated on the heavier salt water, causing nutrients to be deposited on the bottom of the lake, resulting in the accumulation of a more than five-kilometre (3 mi) thick deposit of sediment on the bedrock.

In the Pliocene, the depression of today's Lake Maracaibo reached what would be practically its current form. The numerous rivers that flow into the lake have been defining its banks, especially those that form the southern delta of the lake, where the Escalante, Catatumbo and Santa Ana rivers converge.

Lake Maracaibo is located in the Maracaibo lowland in the faulted basin between the Perija Mountains and the Merida Mountains of the Eastern Cordillera Mountains in northwestern Venezuela. The lake is in the shape of a vase. It is 210 kilometres (130 mi) long from north to south, 121 kilometres (75 mi) wide from east to west, covers an area of 13,512 square kilometres (5,217 sq mi), the deepest is 35 metres (115 ft), the shore length is about 1,000 kilometres (620 mi), and the volume is about 280 cubic kilometres (67 cu mi). The largest river entering the lake, the Catatumbo River, enters the lake from west to east, providing 57% of the water entering the lake. In addition to the influence of the prevailing wind, the lake water circulates counterclockwise. There are also the Santa Ana River, Chama River, Motatán River, Escalante River, and about fifty other rivers which drain into it.

Lake Maracaibo is deep in the south and shallow in the north. The northern half of the lake, which looks like a bottleneck, is 55 kilometres (34 mi) long. The southeastern edge of the lake basin with a flat bottom is steep and the northwestern edge is gentle. The southern part is lighter due to river water injection, while the northern part is slightly salty due to tidal influence. The Catatumbo River forms a bird-foot-shaped delta in the southwest of the lake basin, and the surface lake water in the delta has a salinity of only 0.13%. However, the intrusion of seawater from the mouth of the lake makes the salinity of the bottom lake water higher, reaching 0.2–0.3%. The north is connected with the Gulf of Venezuela, and the spit at the mouth of the lake extends for about 26 kilometres (16 mi).

The annual average temperature of the lake area is 28 °C (82 °F); the precipitation is more in the south and less in the north, and the average annual rainfall in the south is 1,400 mm (55 in). The mountain wind from the Andes at night contacts the warm and humid air over the lake surface, contributing to an average rainfall of 297 mm (11.7 in) per year. The meteorological phenomenon known as Catatumbo lightning takes place over the southern part of the lake, characterized by a continuous series of lightnings that are almost silent. This makes Lake Maracaibo the place with the most frequent lightning on Earth. There are about 233 lightning strikes per square kilometre in a year on average. The nocturnal thunderstorms occur on average about 297 days per year. At its peak in September, the lake area can experience up to 280 lightning strikes per hour, approximately 28 lightning strikes per minute, lasting up to nine hours, and capable of illuminating nighttime navigation.

The aboriginal Añú [es] people who lived on the banks of the lake refer to it as Coquivacoa. The tribes of Wayuu, Caquetíos, and Quiriquires also lived in the area. When Italian navigator Amerigo Vespucci and Spanish explorer Alonso de Ojeda's fleet sailed here on August 24, 1499 (the first time Europeans entered this area), the stilt houses in which the Añú lived in reminded Vespucci of the Italian city of Venice, so he named the region Veneziola (Venezuela in Spanish), or "Little Venice". Spain made two attempts to establish settlements around the lake in 1529 and 1569, but it was not until 1574 that the city of Maracaibo was successfully established. The Privateer Henry Morgan raided settlements on the lake in the Spring of 1669 and defeated a Spanish squadron sent to intercept him. On July 24, 1823, Venezuela won the famous Battle of Lake Maracaibo on the lake during the Venezuelan War of Independence.