The avalanche that flooded the North and West of Cali with mud last week was not only a consequence of the rains that exceeded historical records and the lack of civility of the people of Cali who throw garbage that ends up in the sewers, but also of the deforestation of the tutelary hills, its excessive urban growth and the shortcomings in the water management of its streams.
This is supported by sanitary engineers, urban planners and academics, who have been warning of the situation. Which is not exclusive to this sector but to the entire hillside of Cali.
Hugo Salazar Jaramillo, sanitary engineer, former Emcali aqueduct manager and former president of the Colombian Association of Sanitary and Environmental Engineering, Acodal, maintains that Cali’s planning has been failing for many years regarding how water is managed when it rains.
“With climate change, cities cannot invest in large pipelines or large canals, no one will pay for that,” he says.
So, what is the solution? Salazar explains that in cities like Copenhagen, Tokyo and Chicago there are large tanks under the city that store rainwater to prevent flooding, but that is very expensive for a city like Cali.
Facing the North and West of Cali, he explained that three large retention lakes have to be made in the Chipichape sector to prevent flooding on Sixth Avenue. “These works have been contemplated since the 90s and were not done, but buildings were built.”
He reiterated that the possibility of continuing to build more on the Cali hillside should not be given.
“Because that cuts the leg of the hills and when the water comes from the upper part it causes flooding. The Territorial Planning Plans only authorize two-story homes to be built on hillsides on lots between 2,000 meters and 3,000 square meters. Here it has not been done and little has been reforested. Cali has to change its planning thinking, otherwise, with climate change, these floods will be repeated and we will continue in the pot,” he complements.
The sanitary engineer specifies that these regulation lakes already exist in Cali, but more must be built.
“In the Cañaveralejo sector there is one that fills up when it rains. Likewise, the El Pondaje and Charco Azul lagoons fulfill this function in the East. In Commune 22 there is the La Ballena lagoon,” explains Salazar Jaramillo, who insists that the Cali hillside must also be reforested so that it retains the entire torrent of rain.
The expert specified that Cali could adopt the sponge city model, as is being done in some cities. “Sponge cities are those that apply nature-based solutions, such as green roofs, permeable pavements, along with the restoration of urban and peri-urban wetlands and rivers, seeking to mitigate the negative impacts of urbanization on ecosystems.”
Why was the North flooded?
Julián Ricci, architect and urban researcher, who shared the map that we include in this note, explained that in this sector a large part of the slope of the hill has parking and housing developments that mean that when it rains the water runs and is not retained by areas. soft (earth).
“Something that can be evident is that between the Tres Cruces-Bataclan ecopark and the urban area of Santa Mónica, La Campiña and Chipichape there is a giant system of streams (see map) and for much of the year one does not see the water superficial, but when it rains they collapse. The impact on that polygon is high,” he maintains.
For his part, John Fredy Bustos, urban planner and university professor, reiterates that some experts propose solutions based on nature.
“Everything that is happening with climate change and the La Niña Phenomenon must rethink us as a city. 20 years ago we had front gardens that allowed the absorption of rain, but we began to think that the city is only cement and pavement and we waterproof everything and that is why the water runs towards the flattest part, that is why Cali has no absorption capacity. , Explain.
“I don’t think Cali is prepared for the La Niña Phenomenon, we are prepared to survive, because the way it has been built makes preparation very difficult, surely we will have the human capacity to attend to the emergency, but after these things happen . Preventatively, we are not doing enough to adapt,” she says.
He concludes by saying that the solution is based on green infrastructure, recognizing these ecosystem changes in Cali and planning according to those climatic cycles.
Sergio Zamora, councilor of Cali, affirms that Cali needs and deserves a Sustainable Urban Drainage System. Since its conventional drainage system is beginning to become obsolete.
“Our cities have been designed and built with more and more cement, making them unsustainable… Cali has a conventional rainwater and drainage system, approximately 90 kilometers that run throughout Cali and in the first 100 days of the year 25 tons were collected. of garbage, that’s why when it rains the canals overflow and flood the city,” he said.
He stated that in the Development Plan, which is currently being studied in the Council, he will insist on sustainable urban drainage systems through water filtration in public spaces.
