1. CITRIS 2010 Real-time monitoring of Managed Aquifer Recharge: Application of thermal methods at remote sites to improve water resources A. T. Fisher 1, A. Racz 1,2, E. Castillo 1,2, J. Vesecky 1, S. Peterson 1, C. Schmidt 1,2, M. Los Huertos 3, B. Lockwood 4 1 CITRIS at UCSC, 2 Graduate student researcher 3 California State University, Monterey Bay 4 Pajaro Valley Water Management Agency

2. CITRIS 2010 California leads the nation… GW usage Normal year: ~40% Dry year: ~60% …in groundwater use…

3. CITRIS 2010 …leading to withdrawals that exceed supply "Normal"year"Dry"year Demand200.5159.8 Supply194.7145.5 Supply – Demand –5.8–14.3 Fresh water withdrawals in CA (millions of acre-feet) How will CA meet current and future fresh water demand?

4. CITRIS 2010 Managed Aquifer Recharge (MAR) is one approach… Harkins Slough MAR project New methods are needed to measure and optimize managed recharge

5. CITRIS 2010 Harkins Slough MAR project Water is diverted from nearby wetland, infiltrates into underlying aquifer The Problem: GW recharge is highly variable in space and time. The Goal: Determine patterns of recharge in real time to assist with operations of MAR systems.

6. CITRIS 2010 The Solution: Remote Autonomous Temperature Sensor (RATS) Network Custom-designed and constructed thermal probes deployed below base of infiltration pond High resolution (1 mK) temperature measurements use heat as a tracer to map out timing and locations of infiltration Data telemetered back to base station in real time, posted at web site for rapid assessment and analysis of infiltration Thermal data combined with pressure measurements to track determine in hydrologic properties below infiltration pond CITRIS seed project

7. CITRIS 2010 Preliminary Results and Plans Thermal method maps variations in recharge infiltration, clogging of base of pond CITRIS instrumentation provides high resolution and rapid data access Thermal method being adapted for "distributed recharge network" of smaller basins in region Future studies should address real- time application of digital signal processing of thermal data Add sensors, enhance web interface for broader use of GW recharge data

8. CITRIS 2010 Summary: Real-time monitoring of Managed Aquifer Recharge (MAR) MAR is an increasingly important approach for enhancing fresh water supplies in CA Tools are needed to improve operation of MAR systems, including access to data in real time from remote locations CITRIS seed funding supported development of inexpensive, robust tools for MAR infiltration monitoring, demonstrated benefits for system operation CITRIS at UCSC