Groundwater storage in adaptation to climate change

The Trust project, funded by the European Commission's Life+ programme and the Italian Ministry of Environment, aims to identify adaptation and mitigation measures to counteract the impacts of climate change on the groundwater of the upper plain in the Veneto and Friuli regions in northeastern Italy. Intensive groundwater abstraction over recent decades has resulted in declining water table levels; this problem, common to many other places in the world, will be exacerbated by future temperature increases unless appropriate solutions are adopted. Trust aims to implement a water balance modelling tool to support institutions in formulating sustainable water management planning policies and best practices. This paper reviews the development and application of the water balance model that simulates water deficit affecting summer crops using agronomic and climatic data at small spatial and temporal resolution. Remote sensing identification methods were employed to map irrigated crops. Projections on the water deficit as a function of climate change have used future precipitation and evapotranspiration patterns derived from climate simulations (SRES-IPCC scenarios A1B and A2) of the Mediterranean region for the twentieth and twenty-first centuries. Model outputs showed that, due to climate change, water deficits for summer crops could be of the order of 400 mm, while the balance model showed that climate change can lead to a reduction of average groundwater resource of about 5–10%, especially in the apical areas of the high plain. However, a significant part of the future water deficit might be recovered through rationalisation of water withdrawal and managed aquifer recharge areas.