Cauca River

The Cauca River is the second most important river in Colombia. It is born near the Laguna del Buey in the Colombian Massif, specifically in the Puracé National Natural Park on the border between the departments of Cauca and Huila. In its route between the Central and Western mountain ranges, the Cauca River passes through more than 180 municipalities in the departments of Cauca, Valle del Cauca, Risaralda, Caldas, Antioquia, Sucre and Bolívar until it flows out near the municipal seat of Pinillos. Its hydrographic basin is approximately 63,300 km². It is the place of various productive activities such as the sugar industry, coffee cultivation, electricity generation, mining and agricultural exploitation. Its main tributaries are the Nechí, La Vieja and Río San Juan (Colombia) rivers.

Origin of name

The current name Cauca has an unknown meaning and it is difficult to pinpoint its origin. It is known that the aborigines called it Bredunco, while the first Spaniards in the region called it Río Grande, Cauca or Marta. The name of Marta comes from the fact that the founders saw the Cauca and Magdalena as brother rivers and named them in honor of the holy sisters of the Gospel: Santa Marta and María Magdalena.

The name of Río Grande hispanicized by the Spanish conquerors is Río Hauca, today Río Cauca is of Emberá origin, Haucadam pronounced Jaucadó, Hauca in Quechua means Big and Dam River.

According to Jaime Arroyo, the Gorrones indigenous people called it “Lili”. Fray Pedro Simón in his Notas Historiales clarifies the current name, stating that its origin is due to a cacique of the region called Cauca, although it is not clear which region this cacique is from, since Cieza de León says the cacique inhabited the region of Mompós.

There is an ancient Roman settlement in Spain called Cauca, present-day Coca in the Province of Segovia.

Course

Caucasian

The Cauca River rises in the department of Cauca, south of Laguna del Buey and southeast of the town of Paletará in the Cauca municipality of Puracé. Near this lagoon, it is also born in the Mazamorras river, which takes a southeasterly direction, opposite to that of Cauca, until it flows into the Magdalena river near the town of Pinillos in the department of Bolívar.

The nascent Cauca River flows northwest from the páramos, between the Puracé and Sotará volcanoes, forming the Paletará Valley. Already in this valley it receives the Negro River, on its left side, and turns taking the south-north direction, marking the limit between the municipalities of Sotará and Puracé.

Shortly before passing the town of Coconuco, it receives the Change and La Calera rivers on its right side. In the change of direction to take the east-west direction, it receives the Las Piedras river again on the right.

In the city of Popayán and its area of influence, the Cauca River passes through more than 10 km of the city, reaching an average width of 40 m. The river leaves Popayán between the hills of San Rafael and Loma Larga until it reaches the town of Río Hondo where it receives the homonymous tributary on the left side shortly before receiving the Palacé (right side) and Sucio (left side) rivers.

After receiving these three tributaries, and already in the municipality of Cajibío, the Cauca flows in a south-north direction to the town of El Dinde, where it receives the rivers Cajibío from the right and Dinde from the left, and enters the Cauca municipality of Morales. Other tributaries further north are the Inguíto and Marilopito rivers on the left, which mark the entrance to the municipality of Suárez.

Continuing north, the Cauca River passes through the first artificial alteration of its flow in the Salvajina reservoir, built by the Autonomous Regional Corporation of Valle del Cauca (CVC). The primary function of this reservoir is to control the waters of Cauca in the winter season, avoiding flooding in Valle del Cauca. The Salvajina dam is also used as a secondary hydroelectric power plant, and reaches more than 22 km in length and up to 1 km in width.

In the northern tip of La Salvajina is the municipal seat of Suárez. After leaving this population, the Cauca river meets the Ovejas river (right side) that marks the limit between the municipalities of Suárez and Buenos Aires.

The river continues northward, passing through several small towns until it reaches the interdepartmental boundary between Cauca and Valle del Cauca at the place where it receives the Timba River on its left bank. This tributary together with the Cauca River and the Desbaratado River (tributary on the right) define the eastern part of the southern limit of Valle del Cauca.

Between the mouths of the Timba and Desbaratado rivers, all the tributaries on the right side are from the department of Cauca and those on the left side belong to Valle del Cauca. In this border section, the most important tributaries on the right side are: the Teta River near the town of Lomitas, the Quilichao River that passes through Santander de Quilichao, and the Palo River that passes through Puerto Tejada.

Cauca Valley

Upon entering Valle del Cauca, the river loses the mountains that channeled it for long stretches in fixed directions and enters an open valley where it becomes sinuous, characterized by multiple meanders and madreviejas.

In the municipality of Jamundí, the first town through which the river passes is Robles, near which there are several Madreviejas corresponding to old courses of Cauca. Subsequently, it crosses through the eastern part of the city of Cali until it reaches the limits of Yumbo, traveling north through the municipality of Yotoco and road 40 near the municipality of Buga, then continuing north along the entire length of the department passing through the municipalities of Roldanillo, La Victoria, La Unión its route between the municipalities of the Subregion of the North, Cartago and Ansermanuevo, to later become the limit between the department of Valle del Cauca and the department of Risaralda.

Risaralda

The Cauca River, in its course through this department, meets the municipalities of Pereira, La Virginia, Quinchía, Marseille and Balboa

Caldas

The river crosses the department of Caldas meeting the municipalities of Anserma, Belalcázar, Chinchiná, Manizales, Neira, Palestina, Risaralda, Riosucio, Supía, Filadelfia, La Merced, Marmato, Pácora, and the municipality of Aguadas.

Antioquia

It begins its journey in the jurisdiction of the municipality of Caramanta on the left bank of the river, just after the mouth of the Arquía river, then it borders between Caldas and Antioquia until the mouth of the Arma river on the right bank of the Cauca, from from there, in the municipality of La Pintada, it goes completely into Antioquia, crossing numerous towns including Bolombolo, Santa Fe de Antioquia, Valdivia, Ituango, Cáceres, Caucasia and Nechí.

During the journey through this department, it receives the waters of numerous and mighty rivers, among which its main tributary, the Nechí River, stands out, which provides an average flow of 830 m³/s.

In the jurisdiction of the municipality of San Andrés de Cuerquia, the Hidroituango reservoir project begins

Sucre

In this department, it runs through the municipality of Guaranda (Sucre), being this the only municipality in this department that is located on the banks of this river.

Bolivar

It runs through the municipality of San Jacinto del Cauca, and is on the border with the department of Sucre. It also passes through the municipality of Achí and, finally, flows into the Magdalena River between the Municipalities of Pinillos and Magangué near the village of Las Flores in the Mojana ecoregion.

Pollution

In its 1,350 km of route, the Cauca River is a wastewater dump for more than 10 million people. The first large polluting load is received in the city of Popayán, where several rivers and streams bring untreated wastewater from about 400,000 people. Popayán itself, with almost 300,000 inhabitants, does not have a wastewater treatment plant (PTAR).

Continuing with the tour, in the Salvajina dam the river rests and oxygenates a little, however, later it passes through 7 gold mines, some of which use mercury in their extraction and before entering the department of the Valle del Cauca there are 8 sand pits between artisanal and industrial.

As it passes through Cali, Cauca still has water below the treatability limits for human consumption, however, the Municipal Companies of Cali (EMCALI) have to spend significant resources on oxygenation in their intakes.

The Cañaveralejo wastewater treatment plant (PTAR-C), treats the wastewater collected by the Cali city sewer before returning it to Cauca, but its capacity is sufficient to clean only 60% of the total of the sewage flow.

The southern collector channel of Cali collects the wastewater of about 200,000 people in the southeast of the city and discharges its water, without treatment, into the Cauca River. This canal passes the Navarro landfill, where the city of Cali dumped 1,800-2,000 tons of solid waste per day. According to reports from environmental entities, from the Navarro landfill, 240,000 cubic meters of leachate leak into the southern collector canal each year, which later passes into the Cauca River with a very high toxic and polluting load.

Environmental authorities, headed by the Valle del Cauca Regional Autonomous Corporation (CVC), imposed closure orders on the Navarro landfill and it finally stopped receiving solid waste in January 2008. This partly alleviated the polluting load that Cali pours into the Cauca River. It should be noted that the southern collector channel is before the intake of Puerto Mallarino, where the city of Cali supplies its aqueduct.

When the Cauca River leaves Cali, passing through the municipality of Yumbo, its oxygen level is zero.

In the rest of its route, Cauca receives daily more than 330 tons of organic waste from cities such as Manizales, Pereira and Medellín.

Tributaries

List of the main direct tributaries of Cauca organized from south to north. Along with some of its indirect tributaries

The San Jorge river used to flow into the Cauca, however, the natural diversion of the Magdalena river at the height of the municipality of El Banco, through the Loba branch, has generated that the Cauca, which previously fed its waters in Magangué, now do it in Pinillos, and the Magdalena now runs through the old channel of the Cauca, making the San Jorge its direct tributary.