Regulations and guidelines on water quality requirements for Managed Aquifer Recharge. International comparison

Managed Aquifer Recharge (MAR) is a promising set of techniques to cope with a variety of water management-related issues. In recent years MAR implementations have witnessed an expansion and greater social acceptance. Nonetheless, there are still some gaps in the scientific, economic and governance dimensions of MAR which need to be addressed. One of these gaps is the lack in many countries of clear regulations addressing MAR. In this paper eighteen regulations and twelve guidelines on water quality standards from around the world have been reviewed to favour the advancement of the legal framework concerning MAR. The review has demonstrated that the existing MAR regulatory frameworks are implemented at different levels (i.e. from regional to international) and consider different aspects such as planning, permitting and monitoring as well as the risk assessment. Most regulations take into account some of these aspects, but seldom all of them. The detailed study and comparison of the water quality standards enabled to define conclusions regarding the differences in maximum allowable concentrations (MACs). Furthermore, this comparison made visible the different approaches to encompass the variability of MAR systems, and also the natural conditions prevailing in the receiving groundwater body. Based on the review of the selected regulations, their advantages and shortcomings, a series of recommendations are proposed for the development of future legal framework entailing the MAR technique.