Thirsty Places: Bogotá

Two hours east of Bogotá by road the forest thins, the air turns cold and wet, and the land opens into a plateau of tussock grass and fog at 3,500 metres where the only things standing are plants the height of a person, with thick stems and rosettes of woolly grey leaves, thousands of them across the slopes like a crowd waiting for something. They are frailejones, and the plateau is the páramo of Chingaza, a national park of two hundred square kilometres of moorland between the capital and the Amazon basin. It rains or drizzles there most days. The soil under the grass is black, deep and almost pure organic matter, and it holds water the way peat does, taking the fog and the rain in and letting them out into the streams over weeks, so that the rivers that leave the páramo run in the dry months. Seven tenths of Bogotá's water comes from those rivers, caught in two reservoirs in the moorland and carried under the mountains to the city.

This article is about where Bogotá's water comes from and why a moorland is a reservoir, what a drought did to it in 2024, how a city of eight million rationed its water for a year, and what leaves the city at the other end.

The sponge

A páramo is a high tropical moorland, found above the tree line and below the snow in the northern Andes, from Venezuela to northern Peru, and it is the water supply of Bogotá, Quito and a dozen smaller cities. Its soils are young and volcanic and so rich in organic matter that they are nearly peat, and the frailejones and the mosses and cushion plants that cover them catch the fog on their leaves and drip it to the ground; the water sits in the soil, which can hold several times its dry weight, and drains slowly. The result is a landscape that stores a wet season and releases it through a dry one, which is what a reservoir does, and that does it across a thousand square kilometres for nothing. The engineers who built Bogotá's supply in the twentieth century understood it well enough to put their dams in the páramo and the park around the dams.

The páramo is also fragile, in the ways the groundwater article on this site describes for an aquifer: drained for pasture, burned, grazed or dug for potatoes, the soil dries, oxidises and loses the capacity that made it a sponge, and it does not come back on a human timescale. Chingaza is protected; the páramos to the north and west of the city, which feed the other reservoirs, are farmed, and the arguments over them, over the mines and the potato fields and the cattle, are the arguments over the city's water.

Chingaza

The Chingaza system is one of the great pieces of water engineering in Latin America and one of the least visible, because almost all of it is underground. The Chuza reservoir, in the heart of the park, catches the rivers of the páramo; a tunnel of about forty kilometres carries the water west through the mountain to a second reservoir, San Rafael, just above the city's edge, and from there to the Wiesner treatment works and down into the pipes. The water arrives clean, cold and soft, needing little more than the coagulation and chlorine of any mountain supply, and the system was built in the 1980s with capacity to spare. The city has grown into the spare since. Chingaza supplies seven tenths of Bogotá, the works at Tibitó on the river to the north supply most of the rest from the reservoirs on the plateau, and the old southern system a little; there is no fourth source, and the plan to add one, a dam on the Sumapaz páramo to the south, has been argued over for twenty years.

The water is also cheap to deliver, in a way the places articles on this site rarely find. The páramo stands above the city, so the water comes down by gravity, through the tunnel and the works and into a network that climbs the hillside districts with pumps only at the top; the city does not lift its water a thousand metres as Amman does, or pump it from the ground as Mexico City does. The utility is public, among the better run in Latin America, and its losses to leaks and theft are about a third of the water put in, which is high by European standards and low by the region's. The cost of the system is in the páramo itself: the park, the rangers, the land that cannot be farmed, and the payments the utility makes to the farmers around the park's edge to keep the cattle off the sponge.

The dry year

El Niño arrived in the middle of 2023 and dried the eastern Andes through the following winter, which is Bogotá's dry season anyway, and in the first months of 2024 the rivers of the páramo fell to a trickle. Chuza, which the city had never seen below a quarter full, went to about sixteen percent in the first week of April, and the utility calculated that at the rate the city was drinking it had weeks of water in the Chingaza system and a northern system that could not take the load. On 11 April 2024 the mayor announced rationing. The city was divided into nine zones, and each zone had its water turned off for twenty four hours, once every nine days, with hospitals and a few essential users on separate lines kept supplied; the car washes were ordered shut, the fountains were turned off, fines were set for washing a car or a pavement, and the utility published the rota like a bus timetable.

The city adapted the way the places on this site have adapted before it. People filled the bathtub and every bucket on the night before their zone's day, as the households of Amman do with their roof tanks; the restaurants bought water by the tanker; the schools in the dry zone sent children home or had them bring water from the previous day. The use fell by about a tenth almost at once, as it did in Cape Town, and the utility turned the rota as the levels moved: nine days, then longer cycles when the rain came back a little, then shorter again when it failed, and by the end of the year the cut had been made less severe and the city had come to live with it. The rains of early 2025 filled Chuza, and on 12 April 2025, a year and a day after it began, the rationing ended. The use per person has not returned to where it was.

The river that leaves

The water that Bogotá takes from the páramo leaves it in the Bogotá river, which runs down the western edge of the city, and for most of a century the river has been, by any measure, one of the most polluted in the Americas. The city's sewage, from eight million people and the tanneries, slaughterhouses and factories along the banks, went into it almost untreated: the single works at Salitre took a fraction of the flow, and the rest went to the river, which fell from the plateau over the Tequendama falls as a brown foam that could be smelled from the road. A ruling of the Council of State in 2014, after a decade of litigation by the people downstream, ordered the city and the region to clean the river, and the programme since has been the largest in the country's history: the Salitre works doubled and upgraded to full biological treatment, and a second works at Canoas, below the city, under construction to take the rest, with the pumping station that will lift the sewage out of the river's channel built first. When Canoas runs, the river will carry treated water over the falls for the first time since the city grew, and the farms of the Sabana below, which irrigate from it, will get water the greywater article on this site would recognise as safe.

What it teaches

Bogotá is the city on this site that drinks from a landscape, and whose year of rationing was the bill for having grown into every drop that landscape could give in a normal year. The páramo is the reservoir, the frailejones are the engineers, and the dry year showed what happens when the sponge is squeezed: a city of eight million with a bus timetable for its water. The rationing worked, the city used less and kept using less, and the answer the utility has reached for is the one every city on this site reaches for in the end, a second source, which here is another páramo and another twenty year argument. The river at the bottom of the city is being cleaned for the first time since the city was small. The rain came back. It will not come back every year.

Seven tenths from a moorland, sixteen percent in the reservoir, and a year of taking turns.