{"id":329,"date":"2014-11-12T00:35:47","date_gmt":"2014-11-12T00:35:47","guid":{"rendered":"http:\/\/faculty.engineering.ucdavis.edu\/ginn\/?page_id=329"},"modified":"2014-11-19T02:55:17","modified_gmt":"2014-11-19T02:55:17","slug":"329-2","status":"publish","type":"page","link":"https:\/\/faculty.engineering.ucdavis.edu\/ginn\/projects\/329-2\/","title":{"rendered":"Tracers for Groundwater Age & Sustainability"},"content":{"rendered":"

Environmental Tracers for Groundwater Age & Sustainability
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Current Funding: UC Seed Grant Program,<\/strong> Environmental tracers in the calibration of aquifer models and management of groundwater (co-PI with Jean-Raynauld de Dreuzy, G\u00e9osciences Rennes), $11,450, 2013-2014.<\/p>\n

Students:<\/strong> Tristan Babey, Jean Mar\u00e7ais\/G\u00e9osciences Rennes; Mohamed Nassar\/UC Davis.<\/span><\/p>\n

Collaborators:<\/strong> Jean-Raynauld de Dreuzy\/Universit\u00e9 de Rennes, France; James McCallum\/CSIRO Australia; Arash Massoudieh\/Catholic University of America.
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Project Summary:<\/strong> Analyses of sustainability of groundwater resources require quantitative tools that tell how groundwater responds to forcing functions that are transient on multiple time scales. These include both engineered effects, e.g., increasing withdrawals or artificial recharge, and natural forcing\u2019s, e.g., weather patterns on seasonal time scales, climate change on decadal or even annual time scales. The resulting residence-time distribution, or age, of groundwater sampled at a given well is a key property that reflects not only local conditions but in fact global information about the subsurface materials along the historical flow path of the water (Mar\u00e7ais et al., in review; McCallum et al., 2014).\u00a0 With the governing equation of groundwater age distributions (Ginn, 1999) we have begun using isotopic data (Massoudieh and Ginn, 2011) in combination with high-resolution three-dimensional regional groundwater modeling to assess the way that moments of age – e.g., mean and variance – varies with space, and how this reflects sustainability of water resources (Woolfenden and Ginn, 2009; Ginn et al., 2009).\u00a0 Importantly, we are exploring how transients due to groundwater pumping and climate change may affect ages.<\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \"SJA.PlanviewCropped\"<\/a> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0 \u00a0 \"HH.SanJoaquinAges\"<\/a><\/p>\n

San Joaquin area plan view.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Mean groundwater ages at sequentially deeper layers in the SJA system.<\/p>\n

Additionally, our inability to measure aquifer properties directly remains the dominant limitation of quantitative hydrogeology. Natural subsurface materials have properties that vary greatly across the numerical grid no matter the scale of resolution. The most promising approach to evaluation of these parameters is to integrate available independent data (groundwater hydraulic head, tracer concentrations and travel times, temperature, geophysical data, etc.) with the model outcomes in a model<\/a> inversion<\/em> that calibrates the distributed parameters to fit both pressure and inferred age or tracer data.<\/p>\n

Important papers on the topic:<\/strong><\/p>\n