Ancient irrigation methods may have contemporary relevance
29 June 2019
Peru suffers from a shortage of water and this deficiency will only worsen as the coastal urban dwellers increase both in numbers and in their intensity of water use, and also as coastal agriculture intensifies. Further, climate change will tend to decrease the supply of water from glaciers.
A recent study from Imperial College suggests reinventing in the modern context some of the methods used by Inca and pre-Inca Andean civilisations. The use of canals for water distribution is well-known. Less appreciated are their methods for storage which included the use of ponds and the diversion of excess wet-season water onto mountain slopes and through rocks. The study found that the time for such diverted water to re-emerge varied between two weeks and eight months with an average time of 45 days.
The authors note that clearly these methods do not solve the problem but could be useful in mitigation and could improve supply by 30% at the beginning of the dry season and by 7% in the later months.