Assessing environmental sustainability: remote sensing and GIS as tools for water resources evaluation

Hazard monitoring and risk assessment of water body pollution are very strategic targets in order to achieve correct territorial planning in Italy. This is highlighted by the recent drought events which occurred in Italy in 1998-1999. Remote sensing techniques together with GIS can give a strong contribution to defining and monitoring the water bodies in respect to volume and quality. GIS can be used in respect to historical data mapping, its integration with remote sensing techniques first allows one to identify the territorial information such as climate, geology, soil, etc. and their principal characteristics. The area of study, representative of a Mediterranean senii-arid climate, shows drought conditions which requires that the water supply be carefully managed and artificially improved, is in fact characterised by the presence of important reservoirs for water supply. Eutrophication is of course reducing exploitable water resources and together with volume reduction makes the hydro-crisis more serious. The eutrophic condition has been investigated from a limnological point of view: nitrogen and phosphorus patterns (nitrite nitrogen, nitrate nitrogen, ammonium nitrogen and total nitrogen, reactive phosphorous and total phosphorous), "a" chlorophyll, phytoplankton composition and estimate. The data have shown an oligo-mesotrophic condition in the Flumendosa reservoir, a meso-eutrophic in the Mulargia reservoir and potentially iper-eutrophic conditions in other reservoirs.