New planning tack needed amid climate change

Posted at 08/21/2012 12:46 AM | Updated as of 08/21/2012 12:46 AM

Political boundaries must give way for better flood control

 

MANILA, Philippines - A day after the rains from the storm-enhanced southwest monsoon or habagat stopped last week, Barangay IVC, right on the banks of the Marikina River, was still flooded.

All kinds of trash bobbed up and down the water that spilled from the river. A jeepney overturned by the force of the currents blocked a doorway. Discarded furniture were being carried away by the water.

Residents wading in the floods then said it would take at least three more days before the water subsides.

“In the past, there were floods but they were only up to our ankles,” Den Ablay, a resident, said. Now, floods as high as their first floor ceiling has become a yearly occurrence.

As heavy monsoon rains paralyzed the metropolis August 7-9, city administrators were confronted by a fact: Manila's only one major drainage system needs a thorough cleaning.

And this means desilting and removing illegal settlers from the banks of Pasig River.

No comprehensive drainage plan

Politicians and the government should realize that Manila – a major river basin – has only one natural drainage to speak of, and that is proving to be insufficient to hold the water from the rains, the chief of the River Basin Control Office said.

Director Vicente Tuddao Jr., of the Department of Environment and Natural Resources – RBCO, said Metro Manila has “no comprehensive drainage plan.”

The Department of Public Works and Highways has a flood control plan, but this will not work if the drainage problem is not addressed, Tuddao said.

“Drainage is foremost,” he explained. “You have to maintain a high volume of flow in the river at a given time."

Metro Manila, he noted, only has one natural drainage – the Pasig River.

But “the Pasig River does not serve its purpose. Its flow is not efficient anymore,” he said. So the question now is “how do you make the water flow quickly?”

The Pasig River is the main feature of the Pasig-Marikina - Laguna River Basin, a land that is drained by a river and its tributaries.

Pasig River's role

According to the Pasig River Rehabilitation Commission, the river serves as the only outlet that drains excess water from the landlocked Laguna de Bai to Manila Bay. It also drains four major river tributaries - the San Juan, Marikina, Napindan and Taguig-Pateros Rivers and a vanishing and often filthy network of 47 creeks and esteros.

The 27-kilometer river traverses the cities of Manila, Makati, Mandaluyong, Pasig, Taguig and the municipality of Taytay in the province of Rizal.

Two years ago, the government decided to desilt the river. According to data from the Pasig River Rehabilitation Commission, dredgers removed 2.83 million cubic meters of contaminated materials which accumulated in the riverbed and increased the depth of the Pasig River from the previous average of four (4) meters to six (6) meters.

The PRRC also noted that it has relocated thousands of families living in shanties by the river bank.

According to the agency, of the 10,113 target informal settler families illegally occupying the ten-meter easement of the Pasig River 9,351 households have been relocated or given financial assistance.

However, it appears that the clean-up was not enough, Tuddao said. While it improved the carrying capacity of the river, the possibility that it will overflow again is real.

Pasig River as toilet

“Seventy to eighty percent of the waste in Pasig River comes from households,” Tuddao said.

“People use it as their toilet, they throw anything there,” he noted.

“Matter occupies matter,” Tuddao said. If 50% of the river is trash, 50% of the river water will overspill in the event of heavy downpour, he added.

The area where the water from the river and the lake meets is heavily silted. On the other end, near the Manila Bay, informal setters and residential subdivisions clog up the waterway.

He noted that garbage from the legal and illegal communities living on the river banks continue to clog up the Pasig River and its tributaries, slowing down the flow of the water from the inner neighborhoods of the metropolis to the Pasig River and Manila Bay.

The government has announced that 100,000 informal settlers living near danger zones in Metro Manila have to be relocated.

Dwellings and illegal structures along creeks, canals and other waterways would have to be removed to make way for flood control systems that would hopefully solve the perennial floods in the city.

Political boundaries

Tuddao said the national and local governments should change its attitude toward Metro Manila.

He explained that the idea of developing Metro Manila based on political boundary is becoming obsolete in the face of changing climate.

Buildings and development in Marikina City will have an impact on residents in Pasig. Local governments, he said, should see the capital as a river basin, where localities are inter-dependent of each other.

“We should use the river basin concept as a planning tool,” he explained. “Dati kanya-kanya lang."

The Pasig-Laguna River basin is the fourth largest river basin in the Philippines at over 4,100 square kilometers. It is also the most populous, covering six provinces and Metro Manila, the country's economic and political powerhouse. The population in the capital alone stands at 12 million.

To mitigate the flooding in Metro Manila, the Marikina watershed should be restored. This will help lessen the amount of water that rushes downstream.

Local governments should also strictly enforce environment laws and building codes. Tuddao said one of the rules that local governments ignore is the regulation that ban structures within 3 meters from the river bank. Having a wide easement will reduce the impact of households on the water body and lessen the flood risk.

Structural interventions

A structural intervention like a floodway from Laguna Lake to Manila Bay via Paranaque was proposed in the 70s in anticipation of the strain of Metro Manila's growth on the drainage system. However, this did not happen. With the dense population in Paranaque, this is unlikely to happen now, Tuddao said.

Last May, the Aquino administration endorsed a resolution of the Climate Change Cluster at the Cabinet to prioritize interventions in the country's 18 major river basins.

The Climate Change Cluster said: “human activities, including development interventions have significant impact on our river basins.”

Because ecosystems are inter-connected, upland activities such as illegal logging and development have contributed to the siltation and sedimentation of the country's major rivers.

“Many of our river systems are already silted and need to be dredged to enable them to perform their ecological functions well,” the resolution read.

The 18 river basins that will be dredged are: Cagayan RB, Mindanao RB, Agusan RB, Pampanga RB, Agno RB, Abra RB, Pasig-Marikina-Laguna RB, Bicol RB, Abulug RB, Tagum-Libuganon RB, Ilog-HIlabangan RB, Panay RB, Tagoloan RB, Agus RB, Davao RB, Cagayan de Oro RB, Jalaur RB, and Buayan-Malungon RB.