Water chemistry characteristics in small reservoirs of semiarid Tunisia Proceedings of the international seminar rain water harvesting and management of small reservoirs in arid and semiarid areas /Rahaingomanana, Nathalie GESTION DE L'EAU RESERVOIR QUALITE DE L'EAU CHIMIE DE L'EAU ANALYSE CHIMIQUE SALINISATION EVAPORATION IRRIGATION VARIATION INTERANNUELLE ETUDE REGIONALE The variation of water quality in 24 small reservoirs of semiarid Tunisia was studied in relation to catchment and hydrological context duing two successive and contrasting hydrological years. Measured salinities generally satisfied the various uses. Three geochemical groups were identified based on the water quality during the inflow period. Calcium sulphate water types charachterize reservoirs located in Zeroud and Merguellil catchments. They have the greatest dissolved salt contents and an increase of salinity by evaporation may limit their suitability for irrigation. Calcium bicarbonate dominated waters, especially observed in the Medjerda subcatchments, are far more diluted and present less constraints. Two reservoirs located in Cap Bon are made conspicuous by sodium chloride dominated waters with a low ionic content. The salinity of this kind of water increases more quickly with evaporation and can then impose constraints for irrigation use. (Résumé d'auteur) Lund University Berndtsson, R. (ed.) 1999 text https://www.documentation.ird.fr/hor/fdi:010023963 fdi:010023963 Rahaingomanana Nathalie. Water chemistry characteristics in small reservoirs of semiarid Tunisia. In : Berndtsson R. (ed.), . Proceedings of the international seminar rain water harvesting and management of small reservoirs in arid and semiarid areas Lund University, 1999, 95-106 Rain Water Harvesting and Management of Small Reservoirs in Arid and Semiarid Areas : International Seminar, Lund (SWE), 1998/06/29;1998/07/02 EN ZONE SEMIARIDE TUNISIE