Diseases reveal lack of planning in water schemes

- health safeguards lacking

Irrigated agriculture represents only 13 percent of global arable land surface but the value of crop production from irrigated lands is 34 percent of the world total. The proportion of development investment that has been channelled into irrigation schemes is therefore understandable.

Yet, against the undeniable benefits that have accrued from these investments, there must be counted the health problems that have resulted from inadequate planning of the irrigation works. In most developing countries safe water is still to be provided, and waterborne or water-related diseases are endemic over wide areas. Increased human contact with water increases the hazard of infection.

Yet it is only recently, urged by national and international authorities, that the technical planners of irrigation schemes have begun to take these factors into consideration. (Many villagers near the Aswan dam still walk a mile for potable water.) The recommendations of health authorities for the actual zoning of the new agricultural workers' villages have frequently been disregarded at the planning stage. For example, health authorities advise leaving 300 metres between irrigation water courses and inhabited areas, but these spaces are often filled with schools, public buildings and even housing. Schoolchildren,- most prone to infection, use the canals for swimming and relief from the heat.

The borderline between water-borne and food-borne infections is often indeterminable, food being contaminated by water containing pathogens and in its turn serving as a vehicle for infection. Lack of sufficient safe water to dean cooking and eating utensils can obviously play its part in spreading diseases.

The responsibility for bringing elementary health education to this level has generally been left to local health and agricultural authorities. As yet, there appears to have been no development of a general health education system that would inform workers on new irrigation development schemes, and their families living nearby, of the dangers that come with water. In developing countries where increased output of crops has been considered of primary importance, health considerations are too often secondary and water-borne diseases are apt to be considered as part of a local way of life, or death.

The most prevalent water-related afflictions are malaria, spread by 60 varieties of the anopheles mosquito; schistosomiasis, carried by snails; filariasis, propagated by mosquitoes and horseflies; and onchocerciasis, or river blindness, transmitted by small blackflies.

Among these, malaria has been the leading affliction, accounting for as many as 3 million deaths annually. There have been a number of successful malaria eradication programmes over the years, including the global campaign of the World Health Organization. Unfortunately, some of this effort has been negated by the impact of large irrigation and water resource development schemes that provide an ideal habitat for malaria-transmitting mosquitoes. One example of what can happen is to be found in the Cukur and Antakya plains of Turkey where a formerly swampy area was developed through irrigation and drainage schemes for intensive production of cereals, cotton, rice, vegetables and citrus crops. Combined with rapid industrial growth in textiles, cement and engineering, the agricultural development resulted in a large population influx into the region, comprising both seasonal farm workers and a permanent industrial labour force. Throughout the 1960s, a malaria eradication campaign had succeeded in reducing parasite incidence (API) from 10.3 to 0.002 per thousand inhabitants. The localities affected represented only 0.3 percent of the total. In 1970, however, as a result of the growing influx of workers from eastern provinces where eradication programmes were less advanced, a gradual resumption and spread of malaria transmissions became apparent. The proportion of affected localities rose to 18.4 percent in 1972 and 60.0 percent in 1976.

Second only to malaria in its widespread effect on health is schistosomiasis (bilharziasis), a wearing and frequently fatal disease caused by minute worms that are transmitted by snails. It is estimated that 200 million people in 70 countries suffer from the infection, and the World Health Organization reports that it is on the increase.

The evident upsurge of these diseases in new development areas is finally beginning to attract some attention to the need for more careful and better coordinated planning of water resource projects. In the words of a pamphlet issued jointly a few years ago by FAO and the World Health Organization: "The awareness of the potential danger of water schemes is the first step toward protecting the health of the population for whose benefit finally all economic development is undertaken..."