08.01.2004 Feature Article

Water Hyacinth - Threat To Our Water Bodies

Water Hyacinth - Threat To Our Water Bodies
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A GNA feature by Christopher Arko
Accra, Jan 8 GNA - Governments over the years have paid lip service to the water sector especially with regard to the protection and management of the various water bodies in the country.
Time and again people from all walks of life, among them politicians declare loudly that "water is vital for life", but it appears very little is being done to ensure the sustainable use of this all-important resource.
A Water Conference held in Nairobi, Kenya, last year predicted that by 2005, water shortages would be a life threatening issue in Africa. Dr Leticia E. Obeng, a Fellow of the Ghana Academy of Arts and Sciences, in her paper: "Water: A crisis in Development", which she presented at the Fifth Annual Science Lecture of the Academy, attributed the current inaction on the part of Ghanaians to the problem of water hyacinth on water bodies to lack of concern.
Water hyacinth has been acknowledged as the most dangerous floating aquatic plant in the world, which can be rooted in muddy bottoms. Throughout the world hundreds of lakes and ponds have been covered from shore to shore by the plant.
An important characteristic of the plant is that it has a stupendous capacity and its rate of growth is said to be highest of any aquatic or terrestrial plant on earth.
Two plants can produce 1,200 plants in four months; cover an area doubled its size in 12 days and estimated that 0.405-hectare may contain 650,000 plants with bulk weight of 200 tons.
The seeds are long surviving and are believed to be capable of remaining viable for as long as 17 years.
In Ghana, the plant was first noted at a residence in Tema in 1984 and spread to Accra through the activities of horticulturists and flowers vendors. It was seen growing on the Odaw River In the late 1996, infestation of the weed was reported on a tributary of the Black Volta in Burkina Faso and a tributary of River Oti, which starts in Togo.
Water hyacinth infestation poses a number of serious problems to water bodies in the country.
It reduces the surface areas of the river or lake and increases water loss to the atmosphere by three to five times through accelerated evapotranspiration.
Because of its dense growth, the plant causes blockages and prevents the movement of boats and ferries on rivers.
The plants can also clog pipes and inlets of pumping stations and lead to the shutting down of power generation.
A further threat is that, in the long term, if the weed infestation continues unchecked, it would spread over large areas and much of the water body could be eventually lost to land as other plants also begin to grow because of the new conditions created by the presence of water hyacinth.
Of even greater relevance in terms of the ecology and life in water bodies is that the water hyacinth blots out light, endangers oxygen supply, and suppresses phytoplankton and algae growth with serious repercussions for biological productivity and diversity. The weed infestation produces an obnoxious smell that affects the colour and taste of the water.
If the present generation is holding the environment in trust for succeeding ones then every effort should be made to tackle the problem of water hyacinth.
The apathetic attitude so far displayed must be replaced with the vigour that residents of the Central Region used to uproot the plants from the intake point of the headwork of Ghana Water Company to ensure steady water supply to the Cape Coast Municipality recently. Dr Obeng said: "For sometime now we as a people have procrastinated essential actions, through organizing committees and workshops and conferences to discuss the issue.
"Let us remind ourselves that it has been said that the area of water hyacinth infestation increases to twice its size, every 12 days, therefore, the sooner we started serious control action, the better it would be for us."
In some countries including Bangladesh, the hyacinth has been put to various uses such as for making carpets, baskets, animal feed and manure.
In South America, the plants natural enemies, including some insects and microbes, have held it in check.
Of the control methods that have been tried, mechanical harvesting has been found to be effective for limited areas.
Dr Obeng suggested that the most effective way of control was to use bio-control using weevils like Neochemita species and the water hyacinth borer.
Most important preventive measure would be to locate the areas where the plant is growing and deal with it on a long term basis.

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