Araré Lake

About

This is a list of lakes in the Beni Department, Bolivia. The Beni Department lies largely within the Llanos de Moxos, a seasonally flooded tropical savanna of the upper Madeira River basin in the Bolivian Amazon. The Llanos de Moxos landscape includes forested natural levees (alturas), sparsely wooded backslopes (semialturas), and seasonally flooded interfluvial basins (bajíos), with forest islands scattered throughout. Several hundred perennial lakes occur across the region.

Most of the lakes are shallow — typically less than 2 m (6.6 ft) deep, with flat bottoms. Many are distinguished by rectangular or oval outlines and a northeast–southwest orientation; approximately 700 such geometric and 'oriented' lake basins have been identified in the Llanos de Moxos, covering about 1,900 km2 (730 sq mi) (2,600 km2 (1,000 sq mi) including dry lakes). Annual rainfall in the region ranges from 1,600 mm (63 in) to 3,500 mm (140 in), concentrated in a wet season from November to April. Satellite estimates from 1979 to 1987 put the area flooded across the Llanos de Moxos floodplain between 2,069 km2 (799 sq mi) and 78,460 km2 (30,290 sq mi), with a median of 23,383 km2 (9,028 sq mi).

The origin of the oriented lake shapes has been debated. A tectonic model proposed in 1964 argued that rectangular lake basins are surface expressions of subsiding or vibrating basement blocks. A 2014 study rebutted the basement blocks theory, proposing instead a process in which basin depressions were subsequently reshaped by wind and waves. Separately, neotectonic uplift along the southern margin of the Fitzcarrald Arch has been proposed as the origin of larger ria lakes such as El Océano Lake and Rogaguado Lake, whose basins formed as river drainage backed up behind rising knickpoints.

The lakes and waterways of the Llanos de Moxos have been modified by pre-Columbian peoples living in the Llanos de Moxos, who built networks of earthen fish weirs across the seasonally-flooded plains of Baures, as well as settlements linked by causeways and served by canals and reservoirs.

Some of the lakes in the Beni Department lie outside the Llanos de Moxos, in the Southwest Amazon moist forests or the Madeira–Tapajós moist forests.

Adapted from Wikipedia (CC BY-SA)。Photography via Wikimedia Commons.