The Northern Sacramento Valley Branch is pleased to present:
"Potential of Using Agricultural Fields for Groundwater Recharge: Soil Water Balance, Crop Suitability and Surface Water Availability"
Helen E. Dahlke, Ph.D.
Integrated Hydrologic Sciences
Department of Land, Air and Water Resources, University of California, Davis
On-farm recharge (agricultural groundwater banking) is a promising form of managed aquifer recharge where agricultural land is flooded during the winter using surface water to recharge the underlying groundwater. Flooding agricultural fields while the crop is dormant in winter or during fallow periods provides vast land areas connected to irrigation infrastructure that could allow capturing substantial amounts of surface water during wet periods. However, little is known about how much water can be recharged on fields planted with perennial crops like alfalfa or almonds without causing crop injury. The study presented here considers experiments conducted in the Central Valley and the Scott Valley, Siskiyou County between 2014-2016 to test the effect of different winter water application amounts (totals of 2-26 ft) and timings (January through April) on the water balance and crop health of established alfalfa stands and mature almond orchards. Using a water balance model and field observed soil moisture data we estimated that the majority of the applied water (>90%) went to deep percolation within less than 48 hours after the winter water application ceased. Further, yield measurements from the two alfalfa fields and two almond orchards indicate no significant yields loss for both crops. In addition, statistical analysis of daily streamflow records from 93 gauges within the Central Valley, CA reveal that high-magnitude (>90thpercentile) flows provide on average 1.6 and 1 million acre-feet in the Sacramento and San Joaquin River basin for ag-recharge. Together these results highlight the opportunity and potential benefits for growers and water districts to implement on-farm recharge as part of their sustainable groundwater management plans.
Helen E. Dahlke, Ph.D., is an assistant professor in Integrated Hydrologic Sciences at the Department of Land, Air and Water Resources at the University of California. Her research focuses on contributing to a better mechanistic understanding of hydrological processes and their links to climate and biogeochemical cycling. She has extensive experience researching a wide range of hydrological processes in the field including the transport of various constituents (phosphorus, carbon, and nitrate) and conservative tracers. She received her B.S. and M.S. in Geography from the Friedrich-Schiller University of Jena, Germany and her Ph.D. in 2011 in Environmental Engineering from Cornell University with emphasis on soil and water engineering, water resources and environmental geophysics. Before coming to UC Davis in 2013 Dr. Dahlke was a postdoctoral research associate at the Department of Physical Geography at Stockholm University, Sweden where she studied climate change impacts on subarctic hydrologic systems and glaciers in the Scandinavian Mountains. Dr. Dahlke’s current research interests include surface water – groundwater interaction, water resources management, vadose zone transport processes, hydrologic response functions and transit time. On-going projects include testing a new type of environmental tracer consisting of synthetic DNA strands encapsulated by polymer microspheres for flow path characterization in porous media and exploring the feasibility of using agricultural fields as recharge sites for groundwater banking. She has given over 30 presentations and interviews on ag-recharge opportunities in California over the past 2 years.
ANNOUNCING SCHOLASTIC SPONSORSHIP OPPORTUNITIES - ALL PROCEEDS TO BENEFIT SCIENCE STUDENTS:
GRA's Northern Sacramento Valley Branch is interested in supporting university science students. Our Scholastic Sponsorship Program is an opportunity to publicize your business while contributing toward a good cause. Your sponsorship will be acknowledged in the announcement, at the meeting, and space will be provided for a small display and brochures. Please contact Eddy Teasdale at EddyTeasdale@kennedyjenks.com for details.
5:00 – 6:00 – Social Hour
6:00 – 7:00 – Dinner and Announcements
7:00 – 8:00 – Presentation
Members & Non-Members: $20.00
Questions about the meeting or to contact the Northern Sacramento Valley Branch in general, including submittal of your ideas and/or desires for future presentations, please contact Eddy Teasdale at EddyTeasdale@kennedyjenks.com
UPCOMING MEETINGS & EVENTS:
May 3 through 4: SGMS Conference, Double Tree by Hilton, 1150 Ninth Street, Modesto, CA
If you RSVP after Noon on Monday, May 1st, or walk-in, a $2.50 surcharge will be added to the meeting costs. Cancellations must be made by Noon on Monday, May 1st.