COTABATO CITY, Philippines --- Dredging big rivers in low-lying areas in Maguindanao and Cotabato City is just one of the many remedies to perennial flooding and is just a temporary solution.
Engineer Emil Sadain, regional chief of the Department of Public Works and Highways in the Autonomous Region in Muslim Mindanao (ARMM), said construction of dikes and redirecting to shorter routes the water from rivers upstream and from the 200,000 hectare Liguasan Delta are more viable measures than dredging alone.
Sadain, who is an official of the central office of DPWH, but serves as ARMM public works secretary on a concurrent arrangement, said studies and recommendations have been submitted to the national government to address the frequent flooding in the province and in Cotabato City.
The city, which has 37 barangays, is the catch basin for rivers that spring from surrounding hinterlands in Central Mindanao and the downstream flow of the vast Liguasan Marsh at the shared boundary of North Cotabato, Maguindanao and Sultan Kudarat provinces.
Sadain said the dredging of the drain channels of the Rio Grande de Mindanao and the Tamontaka River, both in the western coast of Cotabato City, have to be started from the sea shores going up, not from deep inside the mainland moving downstream.
“And dredging works can only be done during the summer, not during the rainy days,†Sadain said.
Sadain said the silt excavated from the now heavily silted rivers must be dumped along their banks and planted with either bamboos or grass, such as the Vetiver grass, to prevent erosion.
The Vetiver grass (Chrysopogon zizanioides)) is a fast growing perennial grass originally native to India and Sri Lanka, but is now being propagated in the country. It can grow up to 1.5 meter high and form wide base, with roots growing from two to three meters in depth.
The massive growth of water hyacinths on the surface of the Liguasan Marsh that are forced by its downstream gush into the rivers in Maguindanao and Cotabato City has also been hampering the flow of floodwaters to the Moro Gulf, according to Sadain.
Agriculture officials and experts from non-government organizations blamed the continued and excessive use of commercial nitrogen fertilizers for hybrid corn planted by farmers in surrounding hinterlands for the growth of water hyacinths on the surface of the marsh.
have become so destructively prolific.
Heavy rains wash down into rivers the fertilizers corn farmers use, sending them down to the Pulangi River from the adjoining Bukidnon and North Cotabato provinces from the north and the Allah River from the south, that all drain into marshes in Maguindanao before flowing downstream to waterways in Cotabato City.
The floods that hit Maguindanao this week have subsided but, 48, 116 affected families remain in makeshift relief sites and public school campuses, reluctant to return to their villages due to unpredictable heavy rains causing flashfloods.
The ARMM’s education department reported that 115 schools in the first and second districts of Maguindanao remained closed, still inundated by knee-deep floodwaters.
The shutdown of the schools affected 28, 095 elementary pupils and high school students.