possible, ecosystem limits.
Aware of the problems engendered by charging for water, Tunisia has developed voluntary policies to support the control and the valuing of water resources. Considerable efforts have been deployed to develop all water resources using a variety of means (dams, collinear dams, collinear lakes, emission of sewage waters, desalination, drills, surface wells, treatment of used water, recharging water tables). Several geographic zones are connected by a system of regional canals and locks.
During the last ten years (1990-2000), a strategy was devised and implemented to provide integrated control of potential water sources. The cost of this ten year strategy approached two billion dollars. Modeling has been used to demonstrate the working of several water systems in place. This modeling simulates all possible resources and system demands. The simulation model illustrates potential conflicts caused by the need to satisfy water demands and suggests the appropriate timing of activities to provide additional water resources.
In 2003, Tunisia had 27 dams, 180 collinear dams, 600 collinear lakes, and more than 4000 deep wells and 150,000 surface wells exploiting 86% of total conventional water resources. These proposed projects will permit the development of 90% of conventional water resources by the year 2010. In order to increase the water potential in the country, the use of non-conventional water resources, such as treated waste-water and desalinated briny water, is being encouraged. At the same time, the exploitation of water resources is being managed by better allocating the scarce resource. In addition, the protection of coastal aquifers against the intrusion of salt water is reinforced by regulations.
In summary, the exploitation of conventional water resources in Tunisia is very advanced. It is projected that total water demand, due to population increases and increases in living standards, should reach its limit by the year 2030. Conscious of this problem, Tunisia is engaged in formulating a strategy to more fully develop its water resources and to meet the demands of the various socio-economic sectors. The strategy focuses on demand management and integrated planning systems. The cost of developing additional water sources continues to grow. Management, maintenance and system improvements require substantial investments, effective management and technological improvements. The management and exploitation of hydraulic systems in Tunisia must withstand the scrutiny of users who demand more and better performance at minimum risk. Therefore, public and private management must adapt to the new structures and the users must adjust to the need to make prices reflect new system costs.
Irrigation constitutes the largest consumer of water in Tunisia, using 80% of the total water potential in the country. In 2003, agricultural land accounted for about 370,000 hectares. The phreatic water levels irrigated over 150, 000 hectares, while the deep levels irrigated over 70,000 hectares, for a total of 220,000 hectares. Dams irrigated 130,000 hectares, treated wastewater