Quantifying Spatial and Temporal Variability of Mountain System Recharge in Semi-Arid Catchments

Wednesday, April 22, 2009: 11:05 a.m.
Turquoise III (Hilton Tucson El Conquistador Golf & Tennis Resort )
Hoori Ajami , Hydrology and Water Resources, University of Arizona, Tucson, AZ
James Hogan, Ph.D. , Hydrology and Water Resources, University of Arizona, Tucson, AZ
Thomas Maddock III, Ph.D. , Hydrology and Water Resources, University of Arizona, Tucson, AZ
Thomas Meixner, Ph.D. , Hydrology and Water Resources, University of Arizona, Tucson, AZ
Peter Troch, Ph.D. , Hydrology and Water Resources, University of Arizona, Tucson, AZ
Groundwater recharge is likely to be altered as a result of climate change and variability impacting groundwater resources. In semi-arid Basin and Range systems where Mountain System Recharge (MSR) represents a significant component of recharge, this impact is likely to be more pronounced. Despite the importance of MSR in such basins’ water budget, physical processes that control MSR have not been fully investigated. In most groundwater models, MSR is either derived from empirical relationships or estimated during the model calibration and water balance analysis. Therefore, these models are not capable of assessing the impact of climate variability and change on groundwater resources.

The objective of this research is to enhance our conceptual understanding of MSR, and quantify temporal and spatial variability of MSR in selected semi-arid catchments in the Basin and Range of Arizona. Water budget analysis was performed on a seasonal time scale using the Soil and Water Assessment Tool (SWAT2005) and the coupled soil moisture-Hillslope Storage Boussinesq model. Isotopic and soil moisture data were used to provide a constraint on recharge seasonality and water balance partitioning. Preliminary results show annual variability of MSR with pronounced differences in winter and summer seasons. Moreover, a threshold response of MSR to winter and summer precipitation and soil moisture was shown over the simulation period in different catchments. Quantifying these thresholds is important in evaluating impact of climate variability on MSR.