Indigenous Sri Lanka water Management system and its sustainability

Sri Lankan history is mainly associated with the indigenous water management system and hydraulic civilization. Indigenous water management system mainly based on interconnected small tanks and medium scale tanks and channels in north, east and southern areas of the country. Small tanks and its cascade setting has been the major mode of water conservation in the dry and intermediate zones of Sri Lanka. These small tanks form a series of successive water bodies along small water courses and are named a cascading system. Tank cascade system was initiate in the 4th century B.C. or earlier. There are about 12000 working tanks distribute in dry zone of the country and which irrigate an extent of about 185000ha and its covering 35% of the irrigable area of the country. More than providing irrigation water for cultivation in the lowlands, these tank systems function to maintain ground water table up throughout the year, especially during dry periods to support animals, plants and humans. Water is collected in the tank either from seepage or from runoff water passing through the other tanks in the cascade and finally tailored to a large tank. These individual tanks are located in different places, may be in a linear position or in a net work but they are organically combined to form a cascade. This total entity is treated as a watershed and individual tank has its own watershed or micro catchment. These tanks determine the location of the associated human settlement. The traditional cascade systems functioned well as it was locally controlled by the village community. However, with the changes in administrative structure after foreign rule and thereafter, management of tanks came under the government agencies. As a result of climate change the majority of their population in Sri Lanka will face water shortage for economical activities during last period. Reconstruction and of the tank cascade system and maintain ecosystem surrounding of ancient hydraulic posses large potential in adapting to expected environmental change.

کلیدواژه ها:

Ancient ، cascade ، runoff ، rainfall ، irrigation ،