Eline Boelee

Domestic use of irrigation water; the Metfia in central Morocco

Abstract In the modern schemes in central Morocco, traditional methods of water storage in metfias, partially subterranean water tanks, continue to supply domestic water to many villagers. In a cross sectional survey 101 metfias in 21 villages were visited. A few were private household water sources, most of which were shared with neighbors, while others were communal water sources. In order to fill a metfia from the modern irrigation system, the owner must have a water right and a minimum of five hectares of cultivable land. Villagers with no land can use a communal metfia, take water from a neighbors metfia, or use water from canals and siphons. Most metfias were situated in the southern part of the irrigation scheme, where ground water was more than 100 m deep. For most villagers, water from metfias is the only alternative to surface water from the canals and structures in the irrigation system, such as the concrete siphons. In a village that lies outside the irrigation area, water shortage is very frequent. People depend totally on water stored in the collective metfia. The collective metfia was constructed by the government, had a high capacity and was provided with a desilting basin that reduces water silt content before it is stored in a second basin. Water stored in metfias is used for drinking, for a range of domestic activities and for watering livestock. A major problem mentioned by users is the irregular provision of water to metfias from the irrigation network. This study identifies some feasible strategies for improving both the quality and quantity of the water in the metfias, as well as options for building new ones. The importance of intersectoral collaboration and community input into planning and maintenance is emphasized.

Evaluation of environmental methods to control snails in an irrigation system in central Morocco.

The Moroccan Ministry of Public Health has launched a programme to eliminate schistosomiasis. One of the components in this process is the control of Bulinus truncatus, the intermediate host snail of Schistosoma haematobium. We evaluated three environmentally safe measures to control B. truncatus in siphon boxes, the main breeding sites for these snails in the Tessaout Amont irrigation system. The first method involved covering the siphon boxes to exclude light and reduce algal growth, the second consisted of increasing the frequency of emptying and cleaning the siphon boxes, and the third method increased water velocity to hinder the establishment of the intermediate hosts. The results showed that covering had a pronounced effect on snail and egg mass density, was accepted by the local community and prevented water contact. Cleaning the siphons three times during the irrigation season led to a reduction in snail density although it was not statistically significant and recolonization was rapid. Increasing water velocity by reducing the dimensions of siphon boxes delayed recolonization, but such a control measure can be applied only in specific situations where it does not pose hydraulic problems. The three interventions were selectively effective against B. truncatus, whereas other snails such as Physa acuta and Lymnaea peregra were hardly affected. Covering, the most promising control measure, could be useful in the Moroccan schistosomiasis eradication programme. However, further investigations are needed to assess its impact on water quality.

Domestic water use in Morocco' s Tessaout Amont irrigation system

When a new irrigation scheme is introduced, water rights need to be allocated not only to crops for irrigation, but also for domestic purposes.

Trematode infection among freshwater gastropods in Tessaout Amont irrigation system, Morocco

In the summer of 1994 and the spring of 1995, a snail survey aimed at determining relationships between the distribution of molluscan fauna, various environmental factors and trematode infection was carried out in the Tessaout Amont irrigation system, Morocco. The molluscan fauna consisted of nine species belonging to seven families (including one bivalve). Cercariae belonging to nine families were collected. Ancylus fluviatilis and Mercuria confusa showed the highest prevalence of infection (1% and 2%, respectively) but were not listed among infected snails reported from other regions of the country. Melanopsis praemorsa and Bulinus truncates were shedding cercariae belonging to four and three families, respectively. Amphistome and echinostome cercariae were found for the first time in Morocco. No case of mixed-species infections was found.