82-7 Integration of Hydrogeology and Soil Science for Sustainable Water Resources—Focus on Water Quality

See more from this Division: Joint Sessions
See more from this Session: Soil Physics and Vadose Zone Hydrology: Our Future Contributions

Thursday, 9 October 2008: 10:05 AM
George R. Brown Convention Center, 351AD

David Stonestrom, US Geological Survey, Menlo Park, CA and Bridget R. Scanlon, Jackson School of Geosciences, Univ of Texas at Austin, Austin, TX
Abstract:
Salinization and failures to manage soil, carbon, and nutrients have plagued human societies since ancient times. The sustainability of water resources depends on water-quality determining unsaturated-zone fluxes and processes; i.e., on atmospheric and anthropogenic influxes and effluxes of water, solutes, carbon, and energy across the land surface; on biologically mediated processes within the root zone that control and modify these fluxes—especially of nutrients; on chemical processes beneath the root zone that selectively release elements from the solid phase and remove others from solution; and on hydraulic fluxes of advected solutes to the saturated zone. Transported soil can have substantial water-quality impacts when material eroded from the unsaturated zone moves into surface-water bodies. A scarcity of data limits our understanding of unsaturated-zone effects on water quality, which cannot easily be measured from space. Nevertheless, substantial advances in understanding are emerging from ground-based monitoring networks and multi-disciplinary studies. For example, understanding salinization due to land-use change is greatly benefitting from recent findings about natural salinity cycles. Isotopic systems offer a wealth of information about processes, to cite another example. Isotopic discrimination by microbial processes (strongly fractionating), phase changes (moderately fractionating), and atmospheric-generation processes (weakly fractionating) help identify the movement of water and sources of oxyanion salts. Evolving analytical and modeling techniques will continue to spur development of improved process-based knowledge that is essential for addressing agricultural and other land-use pressures on water quality—pressures that can only be expected to intensify in the face of continued population and economic growth.

See more from this Division: Joint Sessions
See more from this Session: Soil Physics and Vadose Zone Hydrology: Our Future Contributions