Special Issue on Managed Aquifer Recharge: Powerful Management Tool for Meeting Water Resources Challenges

As surface water availability becomes uncertain and overdraft of groundwater continues under variable climates, pressure on fresh water supplies will continue to increase to meet the soaring demands for urban development, agricultural production, and ecosystem integrity. Even though other water management strategies—such as interbasin transfer, desalination of brackish and seawater, improvement of water use efficiency, or reuse of reclaimed wastewater—could increase water supplies, there is a considerable potential for managed aquifer recharge to sustain future water supplies (NRC 2008).

Managed aquifer recharge (MAR) describes intentional recharge of aquifers for recovery or for environmental protection and replaces use of the term artificial recharge when groundwater quality protection is also taken into account (Dillon 2005). Systems have evolved from mitigating geological hazards related to groundwater withdrawal, land subsidence, earth fissure, and seawater intrusion to a more proactive and powerful tool for conjunctive management of water resources (ASCE 2001; Pyne 2005; Sheng 2005; Bouwer et al. 2008). Advances and applications of MAR have also been made in recycling or reusing treated sewage effluent or stormwater (Asano 1985; Gonzalez et al. 2014; Knorr and Cliett 1985; Sheng 2005), conjunctive management of groundwater and surface water (Maliva and Missimer 2010; Pyne 2005), short-term storage for peak demands (Maliva and Missimer 2010; Pyne 2005), and long-term storage as a key part of adaptation and sustainability strategies in the face of climate change in many continents including Asia, Europe, and Africa (ISMAR8 2013; Maliva and Missimer 2010), and restoration of ecosystem (NRC 2001).

MAR is an umbrella-term for a range of technologies. Each application is a comprehensive system consisting of multiple elements: (1) source water, (2) pretreatment, (3) recharge facilities, (4) storage space (suitable aquifer), (5) recovery facilities, (6) post-treatment, and (7) end use (purposes) (NRMMC, EPHC, NHMRC 2009; Sheng 2005; NRC 2008). We continue to face challenges in some facets of MAR implementation, for example, poor quality and limited amount of source water, clogging of recharge wells, unwanted chemical reactions and biological activities in the host aquifer, low recovery efficiency when storing fresh water in a saline aquifer, and absence of regulations and policies (NRC 2008).

The 8th International Symposium on managed aquifer recharge (ISMAR8) is the latest of a series of international symposia, focusing on advancing the sciences, application and value of MAR. It is the premier international event on MAR research and practice. The inaugural international symposium on artificial recharge of groundwater was organized by ASCE in August 1988 in Anaheim, California, U.S. (Johnson and Finlayson 1988). It was continued by ASCE in Orlando, Florida, U.S. in 1994 (Johnson and Pyne 1994). In 1998 the International Association of Hydrogeologists (IAH) and UNESCO in partnership with ASCE organized the 3rd symposium in Amsterdam, Netherlands (Peters 1998). Since then it has been held successfully by the same partnership for the consecutive series in Adelaide, Australia in 2002 (Dillon 2002); Berlin, Germany in 2005 (UNESCO 2006); Phoenix, Arizona, U.S. in 2007 (Fox 2007); and Abu Dhabi, the United Arab Emirates in 2010 (ISMAR7 2010). Those conferences advanced the goals of IAH Commission on MAR: to expand water resources and improve water quality in ways that are appropriate, environmentally sustainable, technically viable, economical, and socially desirable (IAH 2014).

The 8th ISMAR was held with a theme MAR: meeting the water resource challenge on October 15–19, 2013 in Beijing, China (ISMAR8 2013). It covers all the facets of MAR systems from advances in technology to the diverse application examples, including hydrogeological characterization of the hosting aquifer, water geochemistry and microbiology, innovative recharge methods, economics of MAR construction and operations, tools for integrated water resources management, and alternative water supplies in a changing climate.

The conference was orchestrated by the Organizing Committee Chaired by Xuan Zhao, Professor of Tsinghua University, and included Weiping Wang and Peter Dillon, Co-Chairs of IAH on MAR; Ben Willardson, Chair of ASCE/EWRI Standards Committee on MAR, U.S.; Alice Aureli, Chief Groundwater Resources and Aquifer Systems Section; NESCO IHP, and others. An international scientific committee chaired by Yan Zheng and Zhuping Sheng was established to promote the conference and provide technical support for paper review and publications of two special issues of journal articles. The special issue of JHE includes papers dealing with engineering aspects of MAR, while a special issue of Journal of Environmental Earth Sciences covers papers related to hydrological and geological aspects of MAR, and a special issue of the MDPI open access journal Water addresses “Policy and Economics of Managed Aquifer Recharge and Water Banking” (Megdal and Dillon 2014).

In this present special issue, authors presented their current research findings on water quality control and clogging issues for the operation and management of a MAR system with stormwater in Australia (Gonzalez et al. 2014; Bartak et al. 2014) and in Bangladesh (Sultana et al. 2014), utilization of horizontal directional drilled wells in the MAR system in the Netherlands (Zuurbier et al. 2014), the removal of natural organic matter from the surface water using MAR systems in Finland (Jokela and Kallio 2014), clogging issues in MAR wells in Spain (Escalante et al. 2014), MAR as a conjunctive management strategy at a river basin scale in Central Asia (Karimov et al. 2014) and Mexico (Nava et al. 2014), harvesting roof runoff for recharging the aquifer (Wang et al. 2014), impacts on the groundwater quality recharged with reclaimed water in China (Zheng et al. 2014), heat, 10B-enriched Boric Acid, and Bromide as recycled groundwater tracers for determining residence time of MAR water (Becker et al. 2014). We are very appreciative for authors’ contribution and efforts and timely submission of their manuscripts.

It is anticipated that this collection will promote further scientific exchange and further advances of our knowledge in MAR and its applications. The next symposium is scheduled to be held in Mexico City, Mexico, in 2016. I recommend that ASCE continue this legacy by publishing selected papers from future symposia in special issues since MAR is attracting more attention from researchers, engineers, and water planners and managers. At the same time, it will enrich our information for ASCE to continue lead development of standard guidelines for MAR systems (McCurry et al. 2013; ASCE 2001).