Weighing the costs of dredging the lake

By Clarice Colting-Pulumbarit, Karen Lapitan
Philippine Daily Inquirer
First Posted 20:48:00 10/14/2009

Filed Under: Ondoy, Health, Weather, Environmental Issues

MANILA, Philippines-Environmental science and agricultural engineering experts believe dredging can solve the rising water level of Laguna Lake but consequences must be weighed.

Dr. Macrina Zafaralla, a professor of environmental science at the University of the Philippines-Los Baños (UPLB), said although she has espoused the dredging of the lake since the 1970s, recent literature has shown that if lake water is disturbed, all toxic and nontoxic sediments at the bottom of the lake would also be disturbed, posing a health hazard.

For land and water resources expert Dr. Victor Ella of the Institute of Agricultural Engineering-UPLB, dredging can lower the lake’s water level at a faster pace but it should be part of a comprehensive plan that includes the management of watersheds surrounding it.

Heavy metals

Zafaralla has been conducting studies regarding the state of the Laguna Lake based on its ecosystem since the 1970s.

She was also part of the team that formed a millennium assessment on the lake in 2005.

“If we disturb all the sediments that had been deposited in the lake for years, even the nontoxic sediments may be transformed into something harmful,” she said.

Possible effects of dredging include the reduction of fish catch, release of noxious odor, and more of the heavy metals present in the lake may be dissolved and released in overlaying water.

“Dredging can make heavy metals available and may be absorbed by algae, algae is eaten by fish, fish is eaten by man. It can be transferred to man and could pose a danger to health,” Zafaralla said.

Heavy metals that have been known in previous studies to be present in the lake are mercury, cadmium and lead which are harmful to humans and can even be cancerous, she said.

“We don’t know the extent of the damage and for how long it will be because it will be a virgin experience for us, but all parts of the lake ecosystem will be affected,” she said.

Zafaralla cited a study of the dredging of a lake in China that changed the water chemistry and composition of algae growing in the lake.

Another study showed that dredging may alleviate the problem only for a time but would return if the entry of pollutants in the lake are not controlled.

Public information

“I espouse dredging but the public will have to be informed of possible consequences,” she said.

Zafaralla said she had also voiced out during a conference on the Laguna Lake before Tropical Storm “Ondoy” struck that people should be informed of how many percent of the time their place would be inundated.

“Government agencies would have already drawn a topography map of which areas around the lake are easily inundated and would be the first to be inundated. There is available data, it should be published,” she said.

“The government should inform people—every municipality should have a map showing the probability of inundation depending on the amount of rainfall.”

A study Zafaralla did in 1977 showed water hyacinth growth in the lake.

Water hyacinth anchors itself to soil, and when it dies, it contributes to natural reclamation of the lakeshore thus, growth shows which areas are bound to get shallower first.

Watershed

In the map showing results, areas with high hyacinth growth could be seen at the Marikina, Rizal and Laguna’s fourth district side which includes the towns of Sta. Cruz and Pakil.

She noted that these were among the areas hardest hit by the overflowing lake during Ondoy.

Ella noted that overflowing of the lake was due to extreme rainfall but also believed it was a contribution of different factors: direct runoff downhill aggravated by deforestation and loss of land cover.

“Overflow is partly the effect of long-term deposition of sediments that is why the lake has become very shallow.”

He said dredging is a good strategy to remove sedimentation and increase the water capacity of the lake but is concerned about its feasibility because it will take a long time.

“Without dredging, outflow of lake water is only through evaporation because there is very minimal seepage of water into the soil. With evaporation, water outflow would only reach 10 mm/day depending on prevailing weather conditions.”

Ella emphasized the importance of land cover and how much it helps despite a large amount of rainfall.

“Through interception of rain, it reduces impact and erosion. Vegetation also increases evapotranspiration which reduces moisture content of soil and increases infiltration capacity of soil. It delays runoff and retards flow of water downhill. Land cover also improves soil aggregation due to increased organic matter content of soil, and this soil will not easily be eroded.”

Comprehensive solution

Ella said dredging should not be a band-aid solution, after which sedimentation and erosion would return.

“The solution should be long-term and comprehensive, both involving watershed and lake management. There should be an over-all agency that will implement an integrated management of the two.”

He added that there were also problems with land-use planning—faulty drainage systems, silted waterways, and residential areas (subdivisions) built onto floodplains.

Ella noted that the concept of a spillway was also a good engineering solution—a connection between Laguna Lake and Manila Bay to serve as a conduit to evacuate excess water from Laguna Lake.

He suggested the creation of a hydrologic model for watersheds surrounding the lake to be able to see and predict the effects of land use change and climate change on runoff and sediments. A hydrologic model is a computer simulation model that mathematically represents the various hydrolic processes like runoff, evapotranspiration, infiltration, percolation, steamflow, baseflow, groundwater flow, erosion, etc., that take place in a watershed in response to rainfall.

Disposal

Laguna Lake Development Authority (LLDA) general manager Edgardo Manda said they were still in the process of planning the long-term dredging of Laguna Lake.

He clarified, however, that the agency plans to dredge the Napindan Channel first as it would help subside the flood around areas near the lake.

He said the dredging should be done regularly.

“LLDA will be responsible for the scientific aspect of the lake’s dredging, but the actual dredging will be done with the help of DPWH (Department of Pubic Works and Highways),” Manda said.

LLDA was still looking to fund the long-term dredging, he added.

He said dredging seemed to be one of the best ways of preventing excessive flooding.

“As for the heavy metal contents found in the lake, the proper disposal will also be part of our plan. People do not have to worry about the health hazards of such as we will carefully plan its disposal,” Manda said.

He said the agency’s experts were looking into the best ways to handle those harmful contents of the lake.

Aside from the sediments accumulated in the lake, the problem of illegal settling should also be addressed, according to Manda, adding that the people living near the lake add up to the problems of clogging the channels where water should freely flow.

“But it’s the solution on illegal settling that should be monitored by the local government units,” he said.

RP shines in dim Earth Hour

Philippine Daily Inquirer
First Posted 01:35:00 03/30/2009

Filed Under: Climate Change, Global Warming, Environmental Issues, Energy Savings

MANILA, Philippines—Tessy Pettyjohn had all the lights in her house in Calamba City in Laguna province turned off on Saturday night, leaving only the fridge on, in celebration of Earth Hour.

“I believe in this. I am a green person, recycling most stuff and never wasting—saving energy most of the time. Earth gets my support,” she said.

Earth Hour was a global effort that encouraged people from all over the world to turn off their lights on March 28, from 8:30 p.m. to 9:30 p.m., to raise awareness about the effects of climate change and global warming.

Pettyjohn said it was her first time to participate in the global campaign to protect the environment, as last year “was not well known and had less publicity.”

While her home remained dark for an hour, she said resorts around her area had kept their lights on.

A basketball game at the municipal hall in Nagcarlan, Laguna, was stopped in observance of Earth Hour.

Astounding success

Residents in other cities and towns across the Philippines also took part in the global campaign.

More than 15 million Filipinos were estimated to have joined Earth Hour and a total of 647 cities and towns participated, making the Philippines No. 1 among all the countries that joined the global event, the World Wildlife Fund (WWF) Philippine representative said Sunday.

“Earth Hour Philippines is an astounding success,” said Yeb Sano, WWF Philippines campaign manager.

Sano said the country’s ranking was based on the initial reports of WWF offices the world over. Greece was second, with 484 participating towns and cities.

Only a million Filipinos were estimated to have joined last year’s Earth Hour. The 10-fold jump in the number of participants this year was attributed by Sano to the Filipinos’ increasing awareness of climate change and its effects.

Only fan, laptop

Donna Orilla, from San Pedro, Laguna, only had the electric fan and her laptop on while all the lights and other appliances at home were turned off.

In Imus, Cavite, former Vice Gov. Jonvic Remulla said almost 30 percent of households had switched off their lights.

In Sta. Rosa City in Laguna, SM Mall switched off the lights of its front façade and logo, and half the lights inside the building.

Pamela Baun, SM public relations officer, said that all SM malls nationwide took part in Earth Hour although each had its own program.

UPLB campus

On the campus of University of the Philippines Los Baños, a total blackout was observed. Chancellor Luis Rey Velasco said “it’s our (UPLB’s) own way of contributing to the solution against global warming.”

Since last week, according to Velasco, there had been efforts to persuade the university’s constituents to unplug appliances and turn off the lights when not needed.

“This (communication campaign) is not for the Earth Hour alone. We want to instill here behavioral change,” he said.

Minutes before Earth Hour, there was a 15-minute program near the campus entrance to explain the benefits of joining the activity.

A 10-second countdown was also held before the clock struck 8:30 p.m. Around 80 students, professors and community residents lit candles as a symbol of their support for Earth Hour.

All the street lamps in Los Baños were turned off, but most establishments did not participate in the activity.

Unaware of significance

In Lucena City in Quezon province, though some parts remained dark for an hour, most of those who joined Earth Hour were not aware of its significance.

“I put off the light just to join because that was the call. But I didn’t know what the reasons were behind that,” said Fe Fernandez, housewife and resident of Barangay (village) Cotta.

However, Fernandez and her neighbors enthusiastically joined the energy-saving activity as they chatted while waiting for the time to turn their lights on. “At least, we were able to save a few pesos on electricity,” a neighbor said.

In Davao del Sur, the provincial police office in Digos City switched off its lights for an hour on Saturday night.

But Elena Enero, 24, of Bansalan town in Davao del Sur, said she did not take part in Earth Hour because she had to watch “Maalaala Mo Kaya” on television.

Another resident, Rey Duran, 28, said he did not turn the electricity off because he wanted to see the televised lotto draw.

Candles, gas lamps

In Davao City, large candles and gas lamps lined up the walkways of the Matina Town Square, a popular compound of bars and restaurants, as the management observed an hour of blackout.

An exhibit that featured local photographers was also mounted. The photos focused on environmental protection.

A cultural group performed before a crowd of students, artists, environmental activists and nongovernment organization workers.

“A little of this, I hope, can do something good to save the world from environmental destruction,” said a student as she signed the “commitment board” mounted for the event.

Marco Polo Hotel also decided to turn half of the number of its lights off.

Flash flood victims

In Cagayan de Oro City, the last time Esther Pajo turned off all the lights in her house was two months ago when floodwater rose very quickly and inundated the house.

Pajo and her family had not gone back to the seaside home in Bonbon village, choosing instead to rent a smaller place far from the sea.

On Saturday, she turned off the house light once again, this time to send a message across.

“The flash flood we experienced was very traumatic. I hope it will never happen again. That’s why I’m doing this, to save Mother Earth, and stop global warming that’s causing all these tragedies,” Pajo said.

In Barangay Consolacion, also in Cagayan de Oro, village leaders exhorted the neighborhood to switch off their lights, and, while only a few houses actually did, the act raised curious questions from ordinary folk.

Fr. Jose Ramon Villarin, president of the Xavier University Ateneo de Cagayan, said the city residents had learned their lesson to take care of their environment the hard way.

“The flash floods we experienced last January taught us a lesson on the importance of environmental preservation. This is only one hour but it will symbolize our resolve to save Mother Earth,” he said.

Poetry

In a program at Plaza Divisoria, Xavier students led the symbolic switching off of lights at exactly 8:30 and, in the darkness, sang, danced and recited poetry.

Cagayan de Oro Electric Power and Light Co. (Cepalco) actively supported Earth Hour. It has been operating one of the biggest solar plants in Asia where it gets 1 megawatt of power that is fed directly into the grid.

In Tacloban City, residents turned Earth Hour into a big walk-in-the-boulevard party and rock concert. At least a thousand people paraded with candles at the city’s darkened 3-kilometer boulevard.

Establishments and houses also joined the worldwide campaign.

The city of more than 217,000 was practically plunged into darkness as homes, establishments and public buildings switched off their lights.

Both the provincial capitol and City Hall buildings and the main office building of the Leyte II Electric Cooperative were in complete darkness for an hour.

Jonathan Calvario, president of the Junior Chamber International-Tacloban, which organized the walk in the boulevard, said he was glad that a majority of the people knew about the campaign.

Members of several fraternities, newly recruited policemen, bikers and other residents joined the parade over 5 kilometers.

The campaign ended with a rock concert on the boulevard participated in by local bands.

In Bacolod City, lights at the Negros Occidental Capitol, the Lagoon Park and all provincial government buildings were turned off for an hour.

The same happened to City Hall, New Government Center, the Bacolod plaza and other city government buildings. Reports from Maricar Cinco, Karen Lapitan and Delfin T. Mallari, Inquirer Southern Luzon; Joey A. Gabieta and Carla Gomez, Inquirer Visayas; Jeffrey M. Tupas, Orlando B. Dinoy and Ma. Cecilia L. Rodriguez, Inquirer Mindanao; and Nikko Dizon in Manila

Laguna fishers make do with ‘kanduli’

By Karen Lapitan
Southern Luzon Bureau
First Posted 00:43:00 02/19/2009

Filed Under: Regional authorities, Fishing

PAKIL, Laguna – A coastal community in Barangay Banilan in Pakil town, Laguna, now rarely sells fresh fish at the market because its catch of commercial fish species has been declining.

Some residents say the low yield was brought by the reported closing of the Napindan Channel, which they consider the pathway of “marketable fish” to their place.

The channel at the northwestern shore of Laguna de Bay connects the country’s biggest inland body of water to the Pasig River and Manila Bay.

“This has affected us, of course. We find it hard to catch even the fish that we could eat,” Prudencio de Guia, 59, who grew up in the village, said in Filipino.

Thousands of people have depended on Laguna de Bay, with an area of 911 square kilometers, for their livelihood.

But the Laguna Lake Development Authority (LLDA) denied that the Napindan had been closed. The channel, located in Taguig City, is under the jurisdiction of the Metro Manila Development Authority.

“That is a misconception. For many years, the Napindan channel has been left open since we know how important it is for the fisherfolk,” its general manager, Edgar Manda, said.

Manda pointed to pollution, siltation and deforestation as reasons for the decline in the fish catch.

More than 70 percent of the 1,000 people in Barangay Banilan rely solely on fishing for their income. But since the fish population has dropped, some are looking for alternative means of livelihood so they can feed their families.

Most of the residents have tried drying their catch of “kanduli” since the fish is not exactly a market favorite.

“If not kanduli, we would get janitor fish. [But] our efforts in catching fish would often be useless,” De Guia said.

Kanduli can tolerate a harsh environment so it is the main variety thriving in Banilan.

De Guia said most of the people dried the fish variety, hoping to earn amid adversity. “This is our own solution to our problem. But this does not give us the income we really need,” he said.

Dried kanduli is sold at P70 per kilo, which is not even a break-even price, De Guia said. “We have no other choice. We don’t want to get hungry,” he said.

Often, the sellers would end up eating the dried kanduli that are not bought.

“The buyers are consistently looking for other varieties. I think they are already fed up with the varieties that we sell,” De Guia said.

Manda said the LLDA had nothing to do with the disappearance of fish in Pakil and other towns in the eastern part of the bay. But he said the agency had been working on some proposed solutions to the fishermen’s problems.

De Guia asked the LLDA to allow small fishermen like him to put up fish cages for free since they were earning almost nothing.

Their cooperative, he said, was paying P4,500 every quarter for a four-hectare fishpen, but the structure could be demolished anytime since the group could no longer pay the dues.

“Most of us have a long list of debts. We don’t know how we can settle the dues,” he said.

Manda said only the illegal fishpens and fish cages were being demolished as these “only promote pollution in the lake, which would worsen the problems of the fisherfolk.”