The Department of Public Works and Highways (DPWH) is now looking at developing permanent structural interventions upstream of rivers, among them the Sabo Dam technology in Cagayan de Oro City.
A kilometer of the technology in Cagayan de Oro is estimated to cost P920 million. Shown above is the Sabo Dam in Camiguin during its construction. The finished dam is shown below.
Sabo dams built in the upstream areas of mountain streams accumulate sediment and suppress production and flow of sediment. Those built at the exits of valleys work as a direct barrier to a debris flow which has occurred. A sabo dam with slits is particularly effective in capturing a debris flow because it has a larger capacity of sand pool under normal conditions.
Below is a simple illustration on how the tehcnology works. On the left shows the dam during normal flow of the river. The dam allows sediment to flow downstream under normal conditions. At right shows the dam reducing the level of sediment discharge from the upstream while river water flows. When a large scale debris flow occurs, sediment is captured and temporarily held here to prevent disasters in downstream areas.
Read the DPWH article HERE.