Sri Lanka reservoirs may need larger sluice gates, canals

Feb 14, 2011 (LBO) - Sri Lanka's reservoirs including those planned or under construction may have to be re-designed with larger spill gates and canals to evacuate excess water following recent rare floods in quick succession this year, officials said. Sri Lanka's Mahaweli river valley agency, which controls 12 large reservoirs says its network is now holding 1,474,000 acre feet of water.

The reservoirs had spilled 1,196,741 acre feet of water during the recent rains. "We have to think about planning for the future.

Reservoirs are normally designed for the heaviest rains in 200 years or 1,000 years," the head of Sri Lanka's irrigation agency G G Godaliyadda said.

"But we expect only one such event at a time. But this time we had two heavy rains in quick succession. This has to be taken into account in our hydrological studies."

Sri Lanka experienced two bouts of heavy rains in January with officials saying that rainfall from December 15, 2010 through January 2011 was three to four times the normal in many areas.

Irrigation minister Nimal Siripala de Silva says larger exit gates and canals may have to be build for all reservoirs and planned projects may also have to be re-designed to account for new hydrological data.

"As a long-term