MANAGED AQUIFER RECHARGE IN THE UNITED STATES: PAST, PRESENT AND FUTURE

Andrew Stone, Executive Director
 American Ground Water Trust, Concord, New Hampshire, USA
astone@agwt.org

            America’s population is increasing by 7,000 each day. Drought, climate-change uncertainties, ecological needs and “maxed-out” supply sources are focusing interest in making greater use of aquifer recharge.  Several US facilities using MAR have been in continuous operation for over 40 years.  There are now over 100 operational entities with many others in various stages of research and development.  These facilities serve needs such as utility supply, irrigation, ecological maintenance, suppression of salt water intrusion and water banking.  Geological host rocks for US aquifer storage include basalts, carbonates, consolidated sedimentary formations and fluvial and glacial sediments.
            Environmental requirements to maintain aquatic habitat now limit the potential of accessing rivers for recharge. Finding seasonably-available, natural source-water is a challenge and there is increasing attention on stormwater peaks and on water reuse as a reliable source.
            The last decade of MAR research and operation has seen advances in understanding the mobilization of metals that may be naturally present in the aquifer, the degradation of disinfection by-products, the attenuation of microorganisms in recharged aquifers and source water treatment technologies.  However, a constraint on MAR adoption in the US is regulatory uncertainty.  The paper examines education and awareness strategies to transfer knowledge from the learning curve of science to the state & federal agencies with authority to regulate MAR.  Water managers need regulatory certainty before proceeding to invest capital in long term strategic plans involving aquifer storage.
            The paper also describes the chronological adoption of MAR in the US, examines legal & regulatory aspects currently constraining more rapid adoption of the technology, and identifies water supply issues in the US where MAR could provide cost effective solutions.