ResearchAxes

  Information management system for LRAE (Laboratory for RadioAnalysis and Environment)

The research program of the "Laboratory of Radio-analyses and Environment" has been designed as a part of the national water resources management strategy. In Tunisia, the availability of water in both quantity and quality is being severely affected by climate variability and climate change, with more or less precipitation in different regions. In many regions, demand is increasing as a result of population growth and other demographic changes such as agricultural and industrial expansion inducing changes in consumption and production patterns. As a result, the country is facing the great challenge of ensuring water resources supply even during critical periods of low water availability.  

Objectives:

Main objectives of the research program of the LRAE have been finalized in order to contribute to protect and develop water resources that are essential to the country’s short-term and long-term economic and cultural viability. These objectives can be divided into two key directions:

• Assessment of water resources availability: There are great differences in water availability from region to region - from the extremes of deserts in the south to sub-humid forests in the north. In addition, there is variability of supply through time as a result both of seasonal variation and inter-annual variation. The unreliability of the resource poses great challenges to water managers in particular and to societies as a whole. In Tunisia, different type of water regulation infrastructureshas been implemented to ensure reliable supply and reduce deficit risks.

• Water quality preservation: Water pollution of water sources is posing major problems for water users as well as for maintaining natural ecosystems.Human activities and human-related substances and wastes introduced into rivers, lakes, groundwater aquifers modify the environmental water quality and make huge quantities of water unsuitable for various uses. In Tunisia, the intensive use of fertilizers has induced a large contamination of groundwater reducing the water availability.

The "Laboratory of Radio-Analyses and Environment" is working on the development and practical implementation of isotope methodologies in water resources management not only in Tunisia but also in Africa.

Research fields of the LRAE can be presented as follow:

• Isotopic Hydrology and Hydrogeology: Classic hydrogeology is a main component of the assessment of potential resources of aquifers. However, isotopes (stable and radioactive) are routinely used as tracers in hydrology for various hydrological investigations e.g., aquifer-aquifer interconnection, surface water-groundwater interrelation, source of groundwater salinity and pollution, origin of geothermal waters, efficiency of artificial recharge, dynamics in lakes, source of recharge and estimation of recharge to the groundwater, ……

• Water quality investigation: The quality of waters is as primordial to manage that its quantity. Indeed, currently and as part of socio-economic development, agricultural sector is extensively encouraged by governmental institutions. This sector is yet recognized to be a very important pollutant of water resources by the intensive utilization of artificial fertilizers and pesticides. Studies focus on investigating water use problems, related to water quality and hydro-geochemical processes (evolution, origin and mixing) of water resources in Tunisia. Different methodologies combined with stable isotopes are employed for this purpose.

• Catchments harvesting: Soil and water conservation services are widely spread in Tunisia to minimize soil erosion and water pollution and to protect wetland resources. Investigations are conducted in order to assess the direct or adverse quality impacts of these management plans on resource quantity and quality. These investigations are multidisciplinary and combine different methodologies.

• Natural radioactivity of water: The analysis of the radioactive components of waters (Tritium, Carbon 14 and Uranium) is an approach used for their characterization and to determine their geographical, climatic and geological origin. Indeed, each area, each climatic phase and of course each formation having contributed to the recharge of the aquifer present different characteristic. The knowledge of these characteristics compared to those of waters should bring a contribution to the determination of the present recharge refill rate.

• Numerical and geochemical modelling: Modelling tools are widely used to test water resources plans and to assess the impacts of both projects and natural events on water resources. Hydrological and hydrogeological models for flow and transport (including variable density models for the simulation of seawater intrusion) are used for water planning in order to contribute to manage and aggregate all the distributed data coming from the different studies and investigations.

The program of the "Radio-analysis and Environment Laboratory" is one of the most important preoccupations of several directions of the Ministry of Agriculture, notably those interested on water resources regulation, and with which the laboratory leads numerous common actions. Some scientific of these directions are, otherwise, members of the laboratory.