Il bilancio Idrico. Una metodologia per la valutazione della compatibilità tra risorsa idrica e idroesigenze ambientali e antropiche

This paper presents an easy to use methodology to evaluate, at basin level, the compatibility between the surface water resources and the environmental and anthropic requirements. The scheme of analysis here presented is composed of four steps: 1) subdivision of the river reach into sub-reaches of interest for the water balance, 2) estimate, with reference to the period of interest, of the river water availability along each sub-reach by using the duration curve, 3) estimate, for the same time interval, of the environmental requirements (minimum flow) and of the water necessary for civil, agricultural and industrial uses, 4) development of a water balance in each sub-reach by considering the effects produced downstream by water resource use in the upstream sub-reaches. The procedure is applied with reference to a basin located in Emilia Romagna, the Lamone river, along which 11 sub-reaches are identified. The results show the potential of the procedure proposed. In particular, this procedure allows for (a) the quantification, with reference to each sub-reach, of the duration in which the withdrawal is possible, (b) the quantification of the maximum discharge to derive in order to satisfy the volume requested (thus making a comparison possible with the discharge that the users can actually derive) and (c) the identification of the situations where the users have to provide reservoirs for temporarily stocking the water withdrawn