Climate change puts water supplies at risk
9 September 2017
Water scarcity is causing huge problems for many communities, towns and, indeed, for the capital Lima.
SEDAPAL, Lima’s municipally-owned water authority, can supply only 23 cubic meters per second when the average current demand is 27, and with as many as 1 million shantytown inhabitants still unconnected.
However, as demand for water increases, the natural supply will reduce as the glaciers retreat and, in the not-too-distant future, could vanish altogether.
Fed by glacial melt, since central and southern coastal Peru has so little precipitation, available ground water is also suffering from over-exploitation, for example from asparagus growing and other agricultural usage. It may be relevant that ANA, the government’s water authority, is located in the agriculture ministry and reflects the interests of the larger agricultural users.
Over the years a ‘healthy’ glacier maintains a balance between the rate of melt and the formation of new ice from compacted snow. But climate change in the high Andes has upset this equilibrium to a point that threatens disaster.
In the dry season, streams disappear where glaciers have already substantially retreated; in the wet season some of what previously fell as snow now falls as rain, causing excess flow that floods and cannot be captured.
In addition, as the glacier melts new areas of rock are exposed and minerals wash out and into the rivers, threatening to poison crops, animals and even people.
To compound the problem, glacial moraine or man-made dams can collapse or be affected. Dam collapse leads to catastrophic flooding in the valleys below such as occurred in Yungay (1970) and Huaraz (1941). Dam collapse or damage can be initiated by an avalanche falling into a lake or reservoir.