The Department of Environment and Natural Resources (DENR) yesterday called on local government units in Metro Manila to work together with the agency in implementing drastic measures that will mitigate recurring issues on flooding.
“Increased rain intensity and frequency due to climate change, depleted forest cover, land conversion and modification of our waterways are among the reasons why Metro Manila and Rizal get easily inundated with floodwaters much too often,” said Carlos Primo David, DENR undersecretary for integrated environmental science, in a statement yesterday.
David said based on DENR’s analysis, Metro Manila is prone to flooding also partly because the entire downstream area, namely Marikina, Cainta and San Mateo are built-up such that rainfall falling into the downstream is converted into floodwaters.
David said the government needs to work together to decrease flood heights downstream by increasing green spaces, transitioning to permeable pavements and implementation of offline flood storage and direct flood water injection.
The DENR is targeting to plant three million trees in the Upper Marikina River Basin Protected Landscape within the next four years in partnership with the Department of Public Works and Highways, non-government organizations, local government units, academe and the private sector.
David, who also heads the agency’s Geospatial Database Office and Water Resource Management Office, said the government is in talks with the private sector for an intensive reforestation of the Marikina Watershed and rehabilitation of the old Wawa Dam.
The DENR also presented satellite images showing how vegetation cover in the 69,817-hectare Marikina River Basin has decreased over the last 10 years n mainly due to urbanization.
“The largest opportunity in decreasing floods are the conversion of moderate vegetation areas into dense forests and rationalize built-up development. Rivers must also be restored and cleared of obstructions within their natural floodplains,” David said.
The Marikina River Basin covers parts of Metro Manila and the province of Rizal, including the 26,123.6 hectare Upper Marikina River Basin Protected Landscape.
Marikina River flows approximately 11 kilometers, with a number of tributaries in the form of creeks and rivers draining to four towns and a city in Rizal province and three cities in Metro Manila which eventually empties into the Pasig River.
David said “no quarrying was found in the protected area or the Upper Marikina River Basin Protected Landscape,” addressing concerns on the thinning vegetation as a result of quarries.
“The areas where there is a stark decrease in vegetation cover coincided with urban development… Meanwhile, the areas that gained forest cover include the reforestation areas east of Antipolo and parts of Rodriguez,” David said.
