El Salto River
The El Salto River, Engaño River, or Tigre River is a natural watercourse that flows through the Patagonian territories of Argentina, where it is called "Engaño", and Chile, where it is called "Tigre" or "El Salto". It is a left-bank tributary of the Carrenleufú/Palena River.
Course
The river originates in Argentina north of Lake General Vintter/Palena, at Cerro de la Virgen, formed by the confluence of several small but abundant streams draining from lakes situated around above sea level, collectively known as the Lagunas del RÃo Engaño. These include Lago Berta inferior and Lago Berta superior.Once formed, the river flows northwest. Shortly after receiving the abundant Arroyo Las Horquetas, it turns west. Three kilometers later, it receives the waters of Valle Hondo, followed by Arroyo Patria from Laguna Virgen.
It then heads north before crossing the border into Chile, where it is known as RÃo Salto or RÃo Tigre. A few kilometers after entering Chile, it abruptly turns southwest until receiving the RÃo El Azul from the south. At the confluence, the Tigre turns north, receives the outflow from Laguna Negra, and finally turns west to empty into the Carrenleufú/Palena River west of the town of Palena.
The Argentine portion of the basin, located in Languiñeo Department, covers. Annual precipitation ranges from 1,500 to 2,000 mm. Precipitation is also abundant in Chilean territory.
In the Argentine basin, the Lagunas del RÃo Engaño include Lago Berta inferior, Lago Berta superior, Lago Engaño, Laguna Cóndor, and Lago Falso Engaño.
Discharge and regime
In normal years, the river experiences peak flows during snowmelt in November and December, but in wet years, the highest flows occur in winter.River discharge varies over time, and one way to represent this is through seasonal variation curves, which, based on long-term measurements, statistically predict the minimum discharge with a given probability of exceedance. The ochre-red curve shows monthly discharges with 50% exceedance probability—meaning half the measured flows in that month are higher and half lower. This is the median, denoted Qe. The arithmetic mean is the mathematical average, denoted.
Once calculated for each month, both values are aggregated annually and shown in the right-hand column of the diagram. A 5% exceedance probability means the discharge is exceeded only once every 20 years on average; 10% once every 10 years; 20% once every 5 years; 85% fifteen times every 16 years; and 95% seventeen times every 18 years. In other words, 5% represents extremely wet years, and 95% extremely dry years. The flood season indicates whether discharge is driven by rainfall or snowmelt.
History
The river was mistakenly identified by Argentine engineer Gunnar Anfin Lange as the Encuentro River on his 1901 map, submitted by expert Francisco Pascasio Moreno to the tribunal of the 1902 arbitral award, laying the foundation for the Alto Palena–Encuentro River dispute.The river valley was central to the boundary dispute between Argentina and Chile over the border between markers XVI and XVII north of Lake General Vintter/Palena, resolved on 24 November 1966 by the arbitral award of Queen Elizabeth II. The ruling awarded Argentina the upper basin and Chile the western basin.
While in Argentina, the river is called "Engaño"; upon entering Chile, it has various names. Hans Niemeyer calls it "Salto o Tigre".
Luis Risopatrón calls it "rÃo del Salto" and describes it as:
Note that in Risopatrón's 1910 map of the area, the Salto and Engaño rivers are incorrectly shown as separated by the Encuentro River.
