1.1.1.WATER RESOURCES The major basins in Chad are: -the basin of the Chari-Logone. The Chari has its source in the Central African Republic and is formed by the confluence of the Bamingui, the Gribingui and the Bangoran. The Bahr Aouk (with a basin of 100,000 km2) joins it later. The average annual flow of the Chari in the city of N'Djamena was 39.1km3 for the period 1950-1971 and 21.8km3 in 1972-2000. There is therefore a trend toward lower rates, from the early 1960s to the low levels of 1984-1985; -the Logone rises in Cameroon and is formed from the Vina and Mbéré. It is later joined by the Lim (45,000km2), the Nya (3,000 km2) and the Pende (15,000 km2); -the catchment area of Mayo-Kebbi, a tributary of the Benue, which is the hyphen between the Chad and the Niger; -the Batha, a temporary river that flows about three months a year and brings to Lake Fitri water volume of the order of 1-2km3/year, with strong interannual irregularities. The largest lake is Lake Chad. In the 1960s, its area measured 19,000 km2 and its coastline 281.5km. The lake stretches over four riparian countries (Chad, Niger, Nigeria, Cameroon). Currently, there are vegetated areas that are seasonally-flooded or permanent swamp or permanently. The lake was completely drained in 1985, so the surface water has varied between 0 (1985, 1987, 1988) and 7,000km2 (1979, 1989 and 2000), depending on the year. Lakes Fitri, Lere, Iro and Toupouri are smaller. Surface water depends on rainfall, characterized by high spatial and temporal variability. Renewable surface water resources are estimated at 13.5km3. Chad has significant groundwater resources. There are large areas of sedimentary formations (sand, sandstone), seats of continuous aquifers in the form of unconfined and deep confined or semi-captive aquifers. These aquifers represent nearly three-quarters of the total land area and are divided into three geoclimatic zones, but are mainly located in the north, west and south of Chad. The annual renewable groundwater resources are estimated at about 11.5km3. With the common portion between surface water and groundwater estimated at 10km3, the total internal renewable resources is 15km3. The average flow of water entering the country by the Chari is currently estimated at 28km3, giving a total of 43km3 of renewable resources. The wetlands are located in the extreme south and on the plains of the two main rivers. The area of Lake Chad, with its water variations, can also be considered wetland. Generally, these are poorly maintained and are subject to significant degradation.

1.1.2.WATER USE The main sectors of water use are: livestock, agriculture, industry, domestic uses, aquatic ecosystems and navigation. Agriculture, with 190 million m3, is by far the biggest consumer of water, mostly from surface water (rivers, lakes, rainwater). Farming uses both surface water than groundwater. Industries often have their own drilling, only the Sugar Company of Chad (TSA) uses surface water for both irrigation and for supplying its factories. Sometimes there are conflicts over certain points of water works related to the shortcomings of mobilization of resources, or their double vocation: pastoral and village. Agriculture consumes about 190 million m3 per year, followed by household use, with 40 million m3 and industry, with insignificant levels of use. Projections show that future oil production will increase the pressure on water resources. However, the projections of the strategy for water and sanitation forecast the predominance of agriculture over other sectors to continue until 2020.

1.2.WATER QUALITY, ECOSYSTEMS AND HUMAN HEALTH Chad’s major environmental problems are inadequate supplies of potable water, improper waste disposal in rural areas contributing to soil and water pollution, and desertification. The country currently still has very little industry; the water quality of rivers poses no problem because the waters are soft and only very slightly soiled. The only problem is the quality of water for irrigation and peri-urban use, as many sources are of dubious quality (non-recycled wastewater, for example). The low level of pesticide use in agriculture limit environmental pollution by these products. Problems with waterlogging and salinity issues exist in the region of Lake Chad.