|CERES No. 121 (FAO Ceres, 1988, 50 p.)|
Around 650 B.C. one Ali Yanouf is believed to have built a dam, some twelve metres high, at Marib in Yemen. Today, just 3 km upstream stands a wall 38 metres high, 227 metres long at the bottom, and 763 metres at the top, barring the course of Wadi Abida at the exit of the gorges of the Djebel Bilak. Ali Yanouf would be proud that the modern behemoth was merely bringing up to date one of his ideas, considered quite daring in their own day.
At some 120 km from San 'a, capital of the Yemen Arab Republic, Marib is situated in a region of high plateau. This is the heart of what, in the first millennium B.C., was the opulent, and already irrigated, land of Sheba, whose queen took King Solomon a gift of "an hundred and twenty talents of gold, and of spices very great store, and precious stones", and asked him "hard questions".
But such wealth is, well, ancient history. Yemen today is one of the poorest countries in the world and was long one of the most stagnant. Its economic situation may be described succinctly with the aid of some indicators of its poverty. Its population growth is too rapid (a rate of 2.8 per cent has brought the population to more than 9 million in 1986, and this rate is expected to exceed 3 per cent between 1980 and 1990); the concept of hygiene is still in its infancy; teaching could be more developed; inflation is galloping; emigrant workers supply labour to all the Gulf States and support their families with their remittances; the balance of payments deficit is astronomical, the amount of imports of food products alone being more than eight times higher than the total value of the country's exports.
Measures to allow the country to attain a degree of self-sufficiency in food were urgently needed. Agriculture was, accordingly, promoted energetically, and the keystone of the new agricultural policy established by the 1987-91 Plan is the development of irrigation.
The Marib dam, begun in 1984, was inaugurated in 1987. Financing of $75 million supplied by the Abu Dhabi Fund for Arab Economic Development covers the building of the dam proper plus the deepening of a 40-km main canal and 10 km of primary canals. Construction was done by a Turkish company. The dam holds back the waters of an artificial lake with a volume of 398 million m3 and a surface of 30.5 km2 the product of flooding the valley of a catchment basin of 10 000 km2. In a first phase, irrigation will extend to 6 340 hectares. In a second phase, still under study, the construction of new works of drainage will double the present area and bring the irrigated surface to 12 000 hectares. Costs are estimated at $30 million.
The new lands thus acquired by irrigation will grow wheat, citrus fruit, green vegetables and vines for table grapes, all for the domestic market. Some "hard questions" still remain, and their solution requires the wisdom of a Solomon. The price of the water and its mode of recovery, for example, are not yet known and nobody is saying anything about how the irrigated areas will be farmed. There are appalling problems of land tenure, since Colonel Saleh's government has not chosen virgin lands to make more productive but territories possessed by rather restless tribes and already being farmed by small producers who have practised irrigation for generations - small-scale artisanal irrigation, of course, by extending the floods (a practice called seil locally) or boreholes or both. This is how 3 301 hectares are still irrigated, since the dam is not yet operational. The farms are intensively cultivated with wheat, barley, sesame, maize, lucerne, legumes, and fruit trees.
Animal husbandry also occupies an important place in the current farming systems and represents an important contribution to income for farms irrigated by boreholes or by a combination of boreholes and seil, and accounts for most of the incomes of those farms irrigated only by seil.
The hydrologists who have studied the zone estimate that these farm level irrigation methods are satisfactory given the present state of affairs. And indeed the possibility of simply continuing as in the past has been considered. But those methods have their limits. The first is the unpredictability of the harvests, the second the damage caused by flooding, the third the accelerated progression of boreholes: recharging the ground water could bring problems in the not too distant future. Finally, the fourth and most compelling limit is that the irrigation systems used till now permits neither increasing productivity nor putting more land under cultivation.
The system should permit six irrigations per growing season, which will involve significant changes in the present situation. Cultivation of sorghum, for example, will be effectively eliminated; this grain needs only one irrigation per season, and continuing to grow it would involve a waste of very costly water. Not only will growing systems be upset, but newly irrigated lands will have to be redistributed. And a number of legal battles over property lines are already in progress.
As attractive as the prospect of not having to import 600 000-650 000 metric tons of wheat and wheat flour every year from Australia, the US, the EEC, Canada, and even Saudi Arabia (imports of 16 000 tons from these countries is foreseen for 1988) may be, the Arab Republic of Yemen needs more than self-sufficiency in food to offset its trade balance deficit. It must reduce imports but also step up exports. In the very near future, Yemen counts on taking advantage of a new resource and joining the oil-exporting countries. One of the many sites surveyed, Alif, is ready to be exploited. The figures advanced on the petroleum reserves of the country are still rough and fluctuate between 300 and 500 million barrels. New prospecting is being done in the Red Sea and in the centre of the country. Exports will begin when construction of the 430 kilometre oil pipeline to link Alif to Salif, on the coast, has been completed, probably in November. Oil revenues which, according to some estimates, could rise to $2.5 billion, would be, for the first time in the world, absorbed in large part into agriculture.