The potential effects of climate change have now become of major concern to Andean countries. Severe climatic events - both droughts and unusually heavy rains - are both more common. Warmer temperatures are already melting the glaciers, which in the past have acted as an insurance policy against drought. There is evidence that the summer wet season is becoming shorter. These factors are already leading to a reduction in water available for irrigation and domestic use, creating an urgent need to improve water management practices.
Terrace farming can itself help to conserve water since there is little surface run-off from the flat platforms. Good drainage ensures that any excess water percolates down from one terrace to the next. Rehabilitated and efficient irrigation canals channel the water to where it can be used to best advantage. The reforestation of hillsides absorbs excess water, stabilizes slopes and helps to protect canals, terraces and human settlements from landslides during periods of heavy rain.
In ancient times there were other efficient forms of water storage. These included above ground reservoirs for storing water for irrigation systems known as 'cochas', some of which CT has helped to restore, and an ingenious system of underground water storage known as ‘almunas’, where rain water and glacial melt water was purposely diverted into natural underground caverns from where it emerged once more along Andean hillsides as springs that were used to provide domestic water and irrigate terrace systems.
CT is now working with highland communities, its local partner AAC and other agencies to continue the investigation and re-use of all these traditional strategies as a means of harnessing water resources that will become increasingly precious in the 21st century. This is not just a critical issue for the mountainous interior. The rivers that rise in the highlands are the life-blood of the commercial agriculture and major industries of Peru’s Pacific coast and of the vast, fragile natural and human environment of lowland Amazonia to the east.