GRACast: Heat and Isotopic Tracers for Evaluating Managed Aquifer Recharge

Presented by:
Matt Becker, Geological Sciences Department, CSU Long Beach
Stephanie Uriostegui, National Park Service, Maryland

Percolation rates in Managed Aquifer Recharge (MAR) facilities can vary widely through both time and space. Natural variations in sediment hydraulic conductivity can create “dead zones” in which percolation rates are negligible. Clogging is a constant problem, leading to decays in facility percolation rates. Measuring percolation rate variations is important for management, maintenance, and remediation of surface MAR facilities. For MAR facilities using recycled water, quantifying and demonstrating subsurface retention time is of high priority. This webinar will explore two different tracer methods for evaluating MAR operations, one method that uses heat and another that uses a naturally-occurring radioisotope.
 
Fiber Optic Distributed Temperature Sensing (FODTS) used to monitor percolation in a long narrow river channel is discussed. The off-river channel was monitored by installing fiber optic cable in a narrow trench and measuring the propagation rate of the diurnal temperature oscillations carried downward with infiltrating water. In this way, heat was used as a tracer of percolation rates along the section defined by the 1,800 meters of trenched cable. FODTS was used to measure percolation in the recharge basin and demonstrate its wide applicability in the river channel. Results from the measurements have been used to understand both the hydraulic behavior of percolation in the facilities and to make management decisions regarding facility operations.
 
Further, a new intrinsic tracer method using the naturally occurring radioisotope sulfur-35 (35S) is discussed. Natural concentrations of 35S found in water as dissolved sulfate (35SO4) were measured in source waters and groundwater at the Rio Hondo Spreading Grounds in Los Angeles County, CA, and Orange County Groundwater Recharge Facilities in Orange County, CA. 35SO4 travel times are comparable to travel times determined by well-established deliberate tracer studies. The study also revealed that 35SO4 in MAR source water can vary seasonally and therefore careful characterization of 35SO4 is needed to accurately quantify groundwater travel time.

Early Registration (by September 21) is $75 for Members* and $100 for
Non-Members*
Registration after September 21 is $100 for Members* and $125 for Non-Members*



SPEAKER BIOS:

Matt Becker is the Conrey Chair in Hydrogeology and Professor in the Geological Sciences Department at CSU Long Beach.  He holds a B.S. in Geology from Michigan State University and M.S. and Ph.D. in Civil Engineering from the University of Texas at Austin.  He has held positions with Chevron USA, and Los Alamos National Labs, and U.S Geological Survey National Research Program. He was a National Academy of Science Senior Research Associate at NASA Goddard Space Center and was a Fulbright Scholar at the University Trento, Italy.  Prior to arriving at the CSULB he was an Assistant then Associate Professor of Geology at the University of Buffalo.  He has been studying fluid flow in fractured rock for 20 years.

 


Stephanie Uriostegui received her PhD in Geology in March 2016 from the University of California, Santa Barbara. She completed her PhD research in groundwater recharge studies at the Lawrence Livermore National Laboratory where she was a Livermore Graduate Scholar from 2012 to 2016. Stephanie’s research focused on the development of a novel analytical method for measuring the naturally-occurring isotope sulfur-35 in dissolved sulfate, which she utilized to quantify groundwater recharge and storage in the Sierra Nevada and managed aquifer recharge facilities. She received a Bachelor of Science degree in Biology from California State University, Fullerton in 2008. Stephanie is currently participating in the Geoscientists-In-The-Park program as a Hydrology Assistant for the National Park Service in Maryland. Stephanie is excited to embark on her career in environmental and water resource management.


MODERATOR BIO:

Adnan Anabtawi is a professional engineer with MWH Global, now a part of Stantec. He is a State of California registered professional civil engineer with several years of experience in water resources planning and groundwater studies in California. Mr. Anabtawi has a Bachelor of Science in Civil Engineering from the University of California, Irvine and a Master of Science in Civil and Environmental Engineering from Stanford University

When?

Wed, Sept. 21, 2016
12:00 p.m. - 1:00 p.m.
(GMT-0700) America/Los_Angeles

Event has ended

Where?

This GRACast will use a conference call for audio and WebEx to display the presentation slides. Each registration is allowed access via one phone line and one log in to the WebEx module. More than one person may participate per registration by using a shared computer screen and speaker phone. ...

This GRACast will use a conference call for audio and WebEx to display the presentation slides. Each registration is allowed access via one phone line and one log in to the WebEx module. More than one person may participate per registration by using a shared computer screen and speaker phone. GRA reserves the right to invoice those individuals and/or organizations that are logged in or connected from telephone numbers that don't correspond to a paid registration.

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