[1] The naturalist and geographer Francisco Pascasio Moreno was apparently unaware of this original toponym, and on an exploration in the spring of 1876 he stopped at the lower part of the Colhué Huapi and Otrón lakes, which he named Musters in honour of the English sailor and globetrotter, who in 1869 had passed near the place, although without getting to know it, on a long expedition of ten months and 2,700 km.

[2] On that adventure, George Chaworth Musters accompanied Tehuelche groups of the chiefs Orkeke [es] and Casimiro Biguá in parleys with Mapuche tribes.

[4] Lake Musters occupies a depression structurally originated at the end of the Cretaceous in the middle of the central Patagonian plateau [es].

After travelling 350 km from these mountain slopes through the central plateau of the province of Chubut, this river brings an average annual flow of 54 m3/s to the entire lower Sarmiento.

[5] Upon entering this alluvial and eolian plain, the Senguerr subdivides into numerous secondary branches (generally dry) in the shape of a fan, oriented towards the northeast.

[6] This branch of the river that connects both lakes has been called Falso Senguerr [es], and its meandering course passes to the north of the locality of Colonia Sarmiento.

[6] Although these two great lakes of the Patagonian plateau present notorious geo-hydrological differences between them, their joint study is unavoidable, since they are part of the same chained water system.

Along its eastern shore it connects with the La Flecha lagoon: low, elongated and with blurred edges, as compromised as its sister lakes by drought.

[8] Lake Musters has an abundant aquatic fauna composed mainly of perch (Percichthys trucha) and Patagonian silversides (Odontesthes microlepidotus).

In addition, under normal conditions, part of its water volume infiltrates, increasing the flow of the Falso Senguer branch, which carries these contributions towards the Lake Colhué Huapi, where the evaporation process is repeated with greater intensity.

There is therefore an increasing decrease in the historical levels of the Lake Musters, and an accelerated process of retraction and drying up in the Colhué Huapi and its periphery.

The current situation could be defined as highly compromised, and constitutes the main environmental threat to maintain the precarious hydro-biological balance of the system.

This means that in two hours the same volume of water that supplies the aqueduct to the cities of Sarmiento, Rada Tilly, Comodoro Rivadavia and Caleta Olivia is lost.

[15] Faced with the prospect of imminent drought, the residents of Sarmiento, alarmed by the drop in water levels, gathered in marches and demanded measures.

Faced with the seriousness of the environmental situation, the Provincial Water Institute belatedly decided to close the illegal intakes of the Senguerr in order to restore the levels of the lake that supplies the Patagonian populations.

The solution to the problem was to be the call for tenders for the closure of the Fontana to regulate the Senguer River, a work that would guarantee the management of the basin.

Because of this diversion by the landowners, practically no water entered the lake, as 20,000 cubic metres per hour were diverted, almost the normal flow for this time of the year.

This was caused by high temperatures and low rainfall, which accelerated the natural evaporation process that occurs both on Lake Musters and on the Senguer River flow.

The phenomenon continued to deepen between January and March, bringing the surface of the lake below the normal operating level of one of the intakes of the aqueduct system.

This work would be the basic solution to regulate the flow of the Senguer River and avoid or reduce the large losses of water due to evaporation.