HR: 0830h
AN: H11C-0880    [PDF]
TI: Application of GIS and Visualization Technology in the Regional-Scale Ground-Water Modeling of the Twentynine Palms and San Jose Areas, California
AU: * Li, Z
EM: zhenli@usgs.gov
AF: USGS, 5735 Kearny Villa Road, San Diego, CA 92123 United States
AB: Application of GIS and visualization technology significantly contributes to the efficiency and success of developing ground-water models in the Twentynine Palms and San Jose areas, California. Visualizations from GIS and other tools can help to formulate the conceptual model by quickly revealing the basinwide geohydrologic characteristics and changes of a ground-water flow system, and by identifying the most influential components of system dynamics. In addition, 3-D visualizations and animations can help validate the conceptual formulation and the numerical calibration of the model by checking for model-input data errors, revealing cause and effect relationships, and identifying hidden design flaws in model layering and other critical flow components. Two case studies will be presented: The first is a desert basin (near the town of Twentynine Palms) characterized by a fault-controlled ground-water flow system. The second is a coastal basin (Santa Clara Valley including the city of San Jose) characterized by complex, temporally variable flow components ­¦ including artificial recharge through a large system of ponds and stream channels, dynamically changing inter-layer flow from hundreds of multi-aquifer wells, pumping-driven subsidence and recovery, and climatically variable natural recharge. For the Twentynine Palms area, more than 10,000 historical ground-water level and water-quality measurements were retrieved from the USGS databases. The combined use of GIS and visualization tools allowed these data to be swiftly organized and interpreted, and depicted by water-level and water-quality maps with a variety of themes for different uses. Overlaying and cross-correlating these maps with other hydrological, geological, geophysical, and geochemical data not only helped to quickly identify the major geohydrologic characteristics controlling the natural variation of hydraulic head in space, such as faults, basin-bottom altitude, and aquifer stratigraphies, but also helped to identify the temporal changes induced by human activities, such as pumping. For the San Jose area, a regional-scale ground-water/surface-water flow model was developed with 6 model layers, 360 monthly stress periods, and complex flow components. The model was visualized by creating animations for both hydraulic head and land subsidence. Cell-by-cell flow of individual flow components was also animated. These included simulated infiltration from climatically variable natural recharge, interlayer flow through multi-aquifer well bores, flow gains and losses along stream channels, and storage change in response to system recharge and discharge. These animations were used to examine consistency with other independent observations, such as measured water-level distribution, mapped gaining and losing stream reaches, and INSAR-interpreted subsidence and uplift. In addition, they revealed enormous detail on the spatial and temporal variation of both individual flow components as well as the entire flow system, and thus significantly increased understanding of system dynamics and improved the accuracy of model simulations.
DE: 1829 Groundwater hydrology
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2003 Fall Meeting