10th International Symposium on Managed Aquifer Recharge Abstract Book

Abstract

How to control saltwater intrusion in coastal zones implementing an appropriated MAR facility? The parameters required to answer that question, include the selection of the most appropriate MAR technology and the best location for MAR having (1) good infiltration rates; (2) enough space to store underground the recharged water; (3) guarantee that the travel time of the recharged water in the aquifer is long enough, compatible with the expected frequency of drought periods; (4) economic efficiency maximization; (5) availability of areas for MAR; and, (6) positive impacts on the society. GABA-IFI model addresses those parameters allowing the selection of the most appropriate place for the location of MAR. Examples will be presented in the paper. Nevertheless, GABA-IFI is not sufficient regarding coastal zones and the expected increase in sea levels worldwide. We have to assess the most vulnerable zones to control groundwater quality degradation assessing vulnerability to saltwater intrusion. GALDIT method is an appropriate toll to assess vulnerability to saltwater intrusion, and today, probably, the most used model towards that aim worldwide. Examples will be presented in the paper. GALDIT uses the hydrogeological parameters such as aquifer properties, hydraulic conductivity, groundwater level, distance from the coastline, current severity of saltwater intrusion, and aquifer thickness to make saltwater intrusion vulnerability indices. The GALDIT gives a weight to each of the indices, and prioritize the indices through a decision-making process, and then assess the possibility of saltwater intrusion by a numerical calculation. GALDIT spatial mapping is acquired using GIS techniques to show the intrinsic vulnerability to saltwater intrusion quantitatively. Worldwide application of GALDIT allow us to assess today and future expected seawater intrusion vulnerability in many coastal regions of the five continents, by applying different sea water level rise scenarios. To counteract the expect harmful eventually catastrophic consequences of saltwater intrusion into coastal aquifers and their groundwater quality Managed Aquifer Recharge is the best NBS and a precious toll, i.e. a sound, safe and sustainable, scientific based, solution. MAR in coastal areas depends on the availability of water including waste water appropriately treated. The optimization of MAR is the aim of the paper, taking advantage of Vulnerability Assessment of saltwater Intrusion using GALDIT model. This will allow the selection of the most vulnerable areas affected or expected to be affected by seawater intrusion optimizing MAR water needs in scenarios of sea level rise due to climate change.