text and photo by Henrylito Tacio

Although several reasons have been cited as to what caused the recent flooding in Cotabato City and its neighboring areas, the main culprit was the free-floating perennial aquatic plant called water hyacinth.

Some 20-hectare spread of water hyacinths invaded the Rio Grande de Mindanao, the largest river in the region near Cotabato City. The water hyacinths reportedly flowed down from the Liguasan Marsh clogged the Delta Bridge – which links Cotabato City and Maguindanao – and caused floods that affected around one million families in the area.

“This is the worst flooding we had in years,” commented Myrna Jo Henry, information officer of the Autonomous Region in Muslim Mindanao (ARMM). “Hindi na nawawala ‘yung baha. Konting ulan, babaha. Hindi na makadaan ‘yung tubig papunta sa dagat dahil sa water hyacinths kaya dumadaloy papunta sa mga komunidad.”

President Benigno Aquino declared “war versus water hyacinths.” But will the government win the war against the innocuous aquatic plants? “A water hyacinth infestation is seldom totally eradicated,” reminds a United Nations study. “Instead, it is a situation that must be continually managed.”

In the Amazon, where it is native, the plant is held in check by natural enemies such as insects and microbes. These organisms stress the plants, controlling the mat’s expansion. But water-hyacinth has escaped to friendlier waters, especially since the 1800s.

Often, visitors, drawn by its lush leaves and blue-to-lavender flowers, have taken it home as an ornamental. Today, it is considered a “pest,” according to the Department of Environment and Natural Resources. It is very prolific; 10 plants could produce well over 650,000 offspring within eight months.

“The plant is far more productive than the crops that have been carefully cultivated by man under near-ideal conditions of fertilization, irrigation, and pest control,” wrote John Bunton in an article which appeared in Far Eastern Agriculture.

Water hyacinth (scientific name: Eichornia crassipes) is considered the most productive plant on earth as it yields more than 200 tons of dry matter per hectare per year under normal conditions. On water containing high concentrations of sewage, it yields up to 657 tons of dry matter per hectare.

The Philippines is not the only country facing the problem. Lake Victoria in East Africa, Kerala’s backwaters in India, Louisiana swamps, and Papua New Guinea have been plagued by the aquatic pest.

The physical problems brought about by water hyacinth are now common knowledge. Water hyacinth mats clog waterways, making boating, fishing and almost all other water activities impossible. Many large hydropower schemes are suffering from the effects of water hyacinth.

But water hyacinths are not the only materials that clog esteros and other bodies of water. Plastic bags, like water hyacinths, are obnoxious. “Plastic bags could be the most ubiquitous consumer item on Earth,” wrote Brian Halweil of the Washington-based Worldwatch Institute. “Their light weight, low cost and water resistance make them so convenient for carrying groceries, clothing or any other routine purchase that it’s hard to imagine life without them.”

Economies worldwide are following suit. “Since they were introduced in the 1970s, plastic bags have infiltrated our lives,” wrote Caroline Williams in an article which appeared in New Scientist. “Globally, we carry home between 500 billion and a trillion every year – about 150 bags for every person on earth, or, to put it another way, a million every minute and rising.”

Today, a growing number of environmentalists has considered plastic bag as public enemy no. 1. “Plastic bags are a waste of resources in that we use them once and throw them away,” Claire Wilton, senior waste campaigner for the London-based Friends of the Earth.

But plastic bags can be controlled. By passing a law, some cities in the country are now banning the use of plastic bags in groceries and malls. But the case of water hyacinth is a different story. “The long range plan is how to stop the water hyacinths from going down to Cotabato,” says Archbishop Orlando Quevedo, chair of Task Force Water Basin in Cotabato. Most of the water hyacinth reportedly comes from upstream areas in Maguindanao and Bukidnon provinces.

At worst, the aquatic plant may be a killer. In the Sepik area of Papua New Guinea, water hyacinth has been blamed for making people starve. According to Australian scientists K.L.S. Harley, M.H. Julien, and A.D. Wright, people “could not access subsistence gardens, hunting areas, catch fish, or travel to market to sell and buy produce” because of dense water-hyacinth mats.

More typically, water-hyacinth damages water quality by blocking sunlight and oxygen and slowing the water’s flow. By choking out other vegetation, it makes an area unusable by plants and animals that live in or depend on the water. “The plants compete with the oxygen needed by fish and other aquatic animals to survive,” Rose Cabrera, a biologist from the Laguna Lake Development Authority, was quoted as saying.

In Lake Victoria, African fishermen have noted that, in areas where there is much water hyacinth infestation, the water is still and warm and the fish disappear. They also complain that crocodiles and snakes have become more prevalent.

In the Florida Everglades of the United States, the snail kite (Rostrhamus sociabilis) is endangered partly because this bird can’t find apple snails – its favorite food – where water hyacinth has smothered the snail’s favored food plants.

In the 1990s, the world reportedly spent US$3 billion a year just to control the weed, for the most part with little or no success. “Its phenomenal growth rate outstrips the systems employed,” Bunton claimed.

Currently, there are several popular control mechanisms for preventing the spread of or eradicating water hyacinth: biological, chemical and physical control. Each has its benefits and drawbacks. Chemical control is the least favored due the unknown long-term effects on the environment and the communities with which it comes into contact.

Physical control, using mechanical mowers, dredgers or manual extraction methods, is used widely but is costly and cannot deal with very large infestations. In Cotabato, backhoes, bolos and brawn were pressed into service. For short-term solution, physical control is alright.

For long-term solution, water hyacinth must be managed and controlled throughout the year. On the water hyacinth problem that caused the recent flooding in Cotabato, Cabrera told a television network, “I think this is a problem that they made worse before it was solved.”

She added that water hyacinths grow fast, and as such, the local government units and the communities shouldn’t have waited for the plant to mature, spread and cover 20 hectares of the Mindanao River with tangled weeds, and block waterways before they acted on the problem.

Experts claim biological control is the most widely favored long- term control method, being relatively easy to use, and arguably providing the only economic and sustainable control.

In some parts of the world, researches have been done to make water hyacinth into a profitable crop instead of a serious pest. In Bangladesh, the Mennonite Central Committee has been experimenting with paper production from water hyacinth for some years. They have established two projects that make paper from water hyacinth stems. The water hyacinth fiber alone does not make a particularly good paper but when the fiber is blended with waste paper or jute the result is reportedly good.

“We will turn the tons of green menace into green products and various items,” said Joel Villanueva, the director general of Technical Education and Skills Development Authority.

In the Philippines, water hyacinth is dried and used to make baskets and matting for domestic use. The key to a good product is to ensure that the stalks are properly dried before being used. If the stalks still contain moisture then this can cause the product to rot quite quickly. Traditional basket making and weaving skills are used.

Another agricultural use of water hyacinth is by turning them into green manure or as compost. As a green manure, it can be either ploughed into the ground or used as mulch. The plant is ideal for composting. After removing the plant from the water it can be left to dry for a few days before being mixed with ash, soil and some animal manure.

Raging floods, frequent typhoons, and water hyacinth proliferation. Is nature fighting back? Or are these phenomena telling us something? Yes, according to the U.S. National Science Foundation and National Oceanic and Atmospheric Administration in its new study: Shifting Band of Rain.

Earth’s most prominent rain band, near the equator, has been moving north at an average rate of 1.4 kilometers a year — for three centuries, writes University of Washington’s Julian Sachs and Conor Myrgvold. Today’s global warming hastened that process.

Think globally, act locally, some environmentalists urge. We need to do something now, before rain continues to pour and water hyacinth clogs the dams, waterways, and hydropower plants. Even before, more people will die from the catastrophes that will happen when nature strikes back.


  • Steve Klaber says:

    Aquatic weeds, such as water hyacinth, are the real driving force in climate degradation. They clog the cooling system, silting up streams and lakes, and preventing or reducing “lake effect” rains. Look at Lakes Chad and Jipe in Africa. There the weed is Typha. In lake Victoria it is water hyacinth. Aquatic weeds are all biomass, waiting to be biofuel(many methods) or compost or biochar… Their renewability is as felonious as human greed for fuel.

  • roger a. garcia iii says:

    ano po ang chemical and physical composition ng water hyacinth? 🙂

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