Isluga River facts for kids
Quick facts for kids Isluga River |
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The Isluga River flowing past a lava flow from Isluga Volcano.
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| Other name(s) | Rio Arabilla, Rio Sitani |
| Physical characteristics | |
| Main source | Confluence of Chaguane and Huinchuta |
| River mouth | Laguna Mucalliri, Salar de Coipasa |
| Length | 54 kilometres (34 mi) |
| Basin features | |
| Basin size | 2,450 square kilometres (950 sq mi) |
| Tributaries |
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The Isluga River is a river that flows through parts of Chile and Bolivia. It's also known by other names like Sitani or Arabilla. This river starts where two smaller rivers, the Chaguane and Huinchuta, meet.
The Isluga River flows for about 54 kilometres (34 mi) (around 33 miles). It eventually reaches Laguna Mucalliri, which is a lake that's part of the Salar de Coipasa salt flat. The river gets its water from nearby volcanoes like Isluga, Cabaray, and Quimsachata, as well as the Sierra Uscana mountains.
Most of the land that drains into the Isluga River is in Chile. This area has a very dry climate. Because of this, the river doesn't carry a lot of water, usually about 0.4–0.5 cubic metres per second (14–18 cu ft/s) (cubic meters per second). Along the river, you can find small towns and villages. There are also important wetlands that are home to many different animals and plants.
Contents
River's Journey
The Isluga River begins at the base of Cerro Alpajeres, a mountain about 4,940 metres (16,220 ft) high. This is west of the town of Chaguane. Here, the Chaguane and Huinchuta rivers join together to form the Isluga. In its early sections, the Isluga River is sometimes called the Arabilla River.
The Chaguane River is about 12 kilometres (7.5 mi) long. It gets water from Laguna Parinacota, a lake fed by two creeks. The Huinchuta River is also about 12 kilometres (7.5 mi) long and flows from the northwest before meeting the Chaguane.
After they join, the Isluga River generally flows southeast and then east. It passes by towns like Chaguane and Arabilla. Near Arabilla, a stream called Quebrada Taipicollo joins the river. The river then flows through wetlands and past towns such as Chapicollo, Enquelca, and Coraguane.
Further along, the river turns sharply south, then southeast-east, and finally eastward. It flows between Cachaguano and Isluga, and then towards Sitani and Cotasaya. The river's last section flows irregularly eastward towards Colchani and Pisigua. After its 54 kilometres (34 mi) journey, the Isluga River flows into Laguna Mucalliri. This lake is part of a larger wetland system connected to the Salar de Coipasa.
The Isluga River flows through areas with river terraces, which are like steps of land formed by the river over time. Several smaller rivers flow into the Isluga. From the north, it gets water from the Quimsachata, Isluga, and Cabaray mountains. The Alsare, coming from Cabaray, is a major stream that joins the Isluga. From the south, the Isluga River receives water from the Sierra Uscana mountains. This includes the 54 kilometres (34 mi) long Mauque River, which joins the Isluga in the Fisica Choque/Chaque wetland.
River's Basin
The Isluga River's basin, or watershed, covers about 2,295 square kilometres (886 sq mi) in Chile's Tarapaca Region and another 145 square kilometres (56 sq mi) in Bolivia. The average height of this area is about 4,187 metres (13,737 ft) above sea level. The land in the Isluga basin is flatter than areas that drain into the Pacific Ocean. This flatter land helps create the wetlands found along the river.
The climate in this region is very dry. Most of the rain falls during the summer months and comes from the Amazon basin. This leads to a steppe type of vegetation above 3,000 metres (9,800 ft) (about 9,800 feet), where it rains about 300 millimetres per year (12 in/year) each year. Higher up, above 2,000 metres (6,600 ft) (about 6,500 feet), the climate is a montane desert, with even less rain, only about 100–50 millimetres per year (3.9–2.0 in/year).
The land in the watershed is mostly made of volcanic rocks. These rocks formed from about 34 million years ago (during the Oligocene) up to today (the Quaternary period). They include types like basalt, andesite, and dacite. In the central and eastern parts, there are also younger sedimentary rocks, including alluvial (river-deposited) and lacustrine (lake-deposited) materials. The 5,501 metres (18,048 ft) high Isluga volcano is still active, with eruptions recorded in 1900 and 1963. Other important mountains in the area are the 5,869 metres (19,255 ft) high Cabaray and the 4,944 metres (16,220 ft) high Cerro El Fraile.
Millions of years ago, during the Pliocene and Pleistocene periods, the Altiplano (a high plateau) was pushed up to heights of over 4,000 metres (13,000 ft). Several river systems, like the Isluga River, flow within this high plateau. In the past, parts of the Isluga basin were covered by lakes. These ancient lakes have left behind the wetlands and smaller lakes we see today.
River Flow
The water temperature in the Arabilla River, a part of the Isluga, is usually between 7–17 °C (45–63 °F) (45-63°F) at an elevation of 3,850 metres (12,630 ft). The water has a lot of salt in it, mainly chloride, sodium, and sulfate. This is because of high evaporation and salts dissolving from the rocks in the area. The waters are also considered eutrophic, meaning they have a lot of nutrients.
Measurements of the river's flow were taken at Bocatoma (between Isluga and Sitani towns) from 1995 to 2001. The amount of water flowing in the river is fairly steady, except during the spring months. On average, about 0.4–0.5 cubic metres per second (14–18 cu ft/s) of water flows through. However, this can increase to over 0.75 cubic metres per second (26 cu ft/s) or drop to less than 0.3 cubic metres per second (11 cu ft/s).
Plants and Animals
The tiny living things in the river, called Plankton, include small plants like Navicula and Synedra. The animal plankton includes small crustaceans like Alona and Bosmina, and other tiny creatures like copepods, ostracods, and rotifers.
Other insects found in the water include Coleoptera beetles of the genus Australelmis and chironomid flies. The river is also home to fish like Orestias agassii and Trichomycterus pencil catfishes, such as Trichomycterus rivulatus. Sadly, these fish are all considered vulnerable or are at risk of disappearing. The Peru water frog has also been found here, along with several types of molluscs and snails like Heleobia.
Many different plant species grow in the waters of the Isluga River. Some examples include Carex, Catabrosa verdermanni, Deschampsia caespitosa, Deyeuxia curvula, Drabella, Distichia muscoides, Distichlis humilis, Eleocharis, Festuca nardifolia, Juncus, Lilaeopsis lineata, Oxychloe andina, Potamogeton strictum, Ranunculus, Sarcocornia pulvinata, Scirpus atacamensis, and Triglochin palustris. These wetlands along the river are very important habitats in the Altiplano region.
The dry grasslands (steppes) around the river basin have plants like quenoa and yareta. The types of plants found in different places depend on how much water is available. Animals in the area include flamingos and vicuñas. You can also find lizards of the genus Liolaemus, the frog Pleurodema marmoratum, and the toad Rhinella spinulosa. While we know a lot about the birds in the area, less is known about the amphibians and reptiles.
Human Activities
The towns of Colchane, Isluga, and Pisiga are located in the Isluga River's basin. This area is part of the commune of Colchane. There are also other small villages and hamlets in the river's watershed. Most of the land in the watershed is undeveloped, meaning it hasn't been built on much. Agriculture (farming) is the main way people use the land here.
The wetlands in the river basin have been important for pastoralism, which is raising livestock like llamas and alpacas. This, along with tourism to the Volcán Isluga National Park, is a key way people in the area make a living. Farmers also use the river's water for irrigation to grow crops.
History
In the 1500s, the Isluga region was part of a group of communities called the Caranga confederation. This confederation stretched all the way to Lake Poopo. At that time, the Spanish Crown wanted to gather the native people into towns. In 1578, the border between two Spanish districts, Corregimiento de Arica and Corregimiento de Caranga, was drawn across the watershed. This line is very close to where the Chile-Bolivia border is today.
See also
In Spanish: Río Isluga para niños
