Stormwater Recharge and Managed Aquifer Recharge: Finding the Link between Improving Groundwater Resources and Stormwater Water Quality Improvement
Managed groundwater recharge to improve groundwater resources and enhance sustainability
The Sustainable Groundwater Management Act (SGMA) has opened a new door for stormwater agencies working to identify opportunities for collaboration in developing infiltration projects. As Groundwater Sustainability Agencies (GSAs) conduct analysis and identify the need for water resources to meet sustainability goals, stormwater will be one of the sources being examined, as mentioned in the recent document published by the Department of Water Resources regarding Water Available for Replenishment (January 2017). Coordination with GSAs and agriculture could provide opportunities for funding for needed stormwater projects. This talk will focus on managed aquifer recharge, the conditions needed to make these projects successful, and ways for stormwater agencies to evaluate projects for benefits under SGMA.
Managed aquifer recharge (MAR) is an increasingly common approach to improve groundwater resources and throughout projects in US, Europe and Australia it has been demonstrated that MAR is a sound, safe and sustainable strategy that can be applied with great confidence. The use of stormwater, recycled water and other alternative water sources in MAR should be enhanced to support the optimization of water resources management through storage of excess water to be recovered in times of shortage and will help the GSAs in meeting the sustainability objectives required by SGMA.
Common recharge approaches used in MAR include injection wells, aquifer storage, and recovery (ASR, with injection and extraction through the same wells), and inﬁltration basins. Injection wells and ASR have low land requirements but can be technically demanding to design, but at the same time they may have high energy, water quality and construction and maintenance requirements for the conveyance and pumping systems. Surface infiltration basins are less demanding regarding engineering and operating costs than injection wells but might not be able to accommodate larger amounts of surface water when available during larger storm and flood events. Approaches to use MAR for recharging the excess of surface water where and when available was less studied in the past but it is now gaining a lot of interest in California due to the potentially significant amount of available land. Using vacant/municipal lands and/or agricultural land for groundwater recharge would provide additional recharge capacity during periods of excess flow, economic water demand during dry years could be satisfied from the groundwater recharge, leaving the available surface water for use to respond to critical environmental needs such as enhanced. Storing excess water in California’s over-drafted aquifers represents a less controversial and lower cost alternative (approximately $300 per AF vs. up to $3000 per AF for surface storage) to construction of additional surface water reservoirs (Purkey et al., 1998).
Here we will present examples of groundwater recharge implementation. The examples will include areas where collaboration between agriculture and municipal agencies could address multiple water quality and water resource goals. Examples of successful projects developed in Europe and Australia, together with ongoing projects in California will be presented: the results from these examples will be used to develop guidelines on how to implement efficient groundwater recharge projects and on how MAR can be an effective way to support the future implementation of SGMA in urban and agricultural basins.
Laura Foglia is senior Engineer with Larry Walker Associate and Adjunct Faculty in the department of Land, Air and Water Resources at University of California, Davis. She has 20 years of experience in groundwater modelling, TMDL implementation, integrated watershed modelling and implementation with focus on understanding integrated groundwater/surface water systems at local and macro-scale with emphasis on model calibration and uncertainty analysis and applications to different watersheds and with coupling to ecohydrological problems and to enhanced water management solutions. She has a MS in Physics (1999) from the University of Milan, Italy, and a Ph.D. in Civil and Environmental Engineering (2006) from the ETH in Zurich (Switzerland).
Ashli Desai is a Vice President with Larry Walker Associates with over 20 years of experience. Ms. Desai has a masters degree in Civil and Environmental Engineering from Stanford University. Ms. Desai specializes in facilitating coordination between municipal agencies, stakeholder groups, and regulatory agencies to provide solutions for solving water quality problems. Her current focus is supporting TMDL development, implementation, and watershed management program development thoughout Southern California.