Peñuelas Lake is one of the main sources of water supply for the Valparaiso region in central Chile. But after twelve years of low rainfall and the catastrophic winter of 2021, the driest on record, it is disappearing irreparably.
Only a large swimming pool resists at one of its ends. Around, thousands of catfish and carp skeletons litter the ground, butchered by crows, seagulls and herons who will soon have nothing left to fish.
“A lot of water reservoirs have not been able to fill up, so year after year they are losing volume (…) We see it in many aquifers throughout the region, the levels are decreasing”, laments James McPhee, Director of the Advanced Center for Water Technologies in Chile.
With that of Los Aromos filled to 46% of its capacity, or 16 million cubic meters, Lake Peñuelas is supposed to ensure the water supply of nearly two million inhabitants of Greater Valparaiso. But today the Peñuelas water reserve is only 170,000 m3, or 0.2% of its capacity (95 million m3), according to the local drinking water distribution and treatment company in Valparaiso. (Esval).
The World Heritage-listed city on the shores of the Pacific, 120 kilometers from Santiago, is among the 50% of Chile’s municipalities officially declared to be in water shortage.
In these 188 municipalities, which have more than 8.5 million inhabitants (47.5% of the population) in the north, center and south of the country, binding measures have been taken: prohibition of water withdrawals surface or underground and resource optimization in agriculture. In the rural areas most affected by the drought, water is distributed by tanker trucks.
“We cannot make it rain more or there is more snow, but we have taken measures for better water management”, indicates Cristian Nuñez, deputy director of the General Directorate of water, dependent on the Ministry of Public Works.
– Three more decades of drought –
In the southern hemisphere, central and southern Chile, but also New Zealand and Madagascar, are experiencing a third less rainfall than 40 years ago, according to the climate change expert from the University of Santiago, Raúl Cordero.
He considers “very likely that hyper-arid winters”, such as that of 2021 in Chile with a deficit of precipitation of 75% and almost 100% of snowfall, “will reproduce much more frequently” elsewhere.
“What has been done so far is an appeal to conscience and goodwill, but that is not enough (…) One way or another we will no longer have to be dependent on rainfall “, estimates Mr. Cordero.
The solution: “having a range of options such as seawater desalination, exploration of fractured rock aquifers, reuse of wastewater, sewage or gray water, which can be used to certain uses,” says McPhee.
Especially since “the situation is not likely to improve in the short and medium term”, warns Mr. Cordero. “We are facing, at best, about 30 years in which rainfall could continue to decline.”
According to the academic, “we will continue to experience a process of desertification in the central zone (of Chile), and the only way to stop this process is to limit the effects of global warming, and the only way is for the world , and not just Chile, is moving away from fossil fuels”.
Because on a global scale “water needs will increase considerably for domestic consumption” (toilets, showers) due to population growth and urbanization, warns the Water Information Center (CIeau).
But above all “other indirect needs will also explode, in particular those related to the agricultural sector”, very water-intensive with nearly 70% of consumption, far ahead of industry (20%) and domestic uses (10%). .