Assessing future water supply and demand in a water-stressed catchment after environmental restrictions on abstractions

The Ali Efenti catchment is a rural upstream subcatchment of the Pinios river basin in central Greece. The average annual precipitation in this subcatchment is relatively higher and groundwater recharge is relatively faster than in the rest of the river basin. Yet, seasonal water shortages occur due to the rapid increase of water abstractions in the summer months, mainly for crop irrigation. Up until 2030 the gap between water supply and demand is expected to deteriorate, considering the impacts of climate and socio-economic change. The adoption of environmental restrictions on water abstraction, which is a measure foreseen in the local river basin management plan, could decrease water stress substantially from 19.2% to 13.9%. However, this would require enormous (−26%) cuts in the current water abstractions during June–September, lowering water demand coverage from 86% to 68%. Optimal combinations of measures, from an economic and environmental perspective, will need to be designed to bridge the gap between water supply and demand and restore water demand coverage to satisfactory levels. Hydrologic and water resources management modelling has been implemented using the Water Evaluation and Planning system (WEAP), which is a conceptual model based on water balances.