Evaluating water resources availability and wastewater reuse importance in the water resources management of small Mediterranean municipal districts

Two low-cost and user-friendly models were developed in an effort to allow small Mediterranean municipalities to evaluate the water resources availability and wastewater reuse importance in their municipal districts. The Water Resources Balance Model (WRBM) ranks each municipal district in four categories according to an innovating scoring methodology based on the adequacy of the existing water resources for potable and irrigation needs. The Wastewater Reuse Importance Model (WRIM) was then used to evaluate the importance of wastewater reuse in water resources balance based on a scoring procedure in which the amount of reusable wastewater was compared with various scenarios of irrigation shortages and needs. The models were applied to 82 municipal districts from the prefecture of Heraklion in the island of Crete. WRBM evaluated eight districts as water scarce while 72% of the districts are water adequate. WRIM evaluated that in 67% of the districts, wastewater reuse is incapable of playing any role of any importance since either water is adequate or the shortage is so great and/or the produced wastewater volume is insignificant by comparison. In total, in only 11 of the districts could wastewater reuse be considered as an important alternative water resource.