Integrated Index Overlay and Numerical Models to Quantify Dynamics of River and Groundwater Interactions in Hyporheic Zones in Dry and Wet Seasons (II)

The nonuniform precipitation in Taiwan have made limited usage of water resources. Such difficulty leads to a challenging task in integrating available water resources for efficient and sustainable management. Hyporheic water flows under a river or stream and the area is the groundwater and surface water interaction zone. The development and management of hyporheic water for water resources requires interdisciplinary knowledge from hydrology and hydrogeology. Over the years, the storage and optimal use of hyporheic water have been the important issues for development of hyporheic water. The dynamics of water interactions in hyporheic zones are fundamental to quantify the storage and optimal use of hyporheic water resources. This three-year study aims to develop a procedure that couples index overlay and numerical models to assess the dynamics of hyporheic water flow for dry and wet seasons in river basins of Taiwan. The index overlay is for identification of large-scale sustainability of hyporheic water resources. A coupled surface water and saturated/unsaturated groundwater models is then used for selected sites to assess dynamics of surface water groundwater interactions in wet and dry seasons. The index overlay method uses selected weighting maps generated by Kriging geostatistical interpolation algorithm. Integrations of the maps than yield the distributions of sustainability for hyporheic water resources. Numerical simulations of surface water groundwater interactions require a physically based model that can reproduce the dynamics of surface water and groundwater interactions. The objectives of the river-scale numerical modeling are to quantify effects of hydrogeological properties on hyporheic water fluxes and dynamics along a river. Additionally, the strategies of hyporheic water management will be systematically analyzed. The procedures and results of this study are expected to provide key references for water resource management and allocations in drought and flood periods in Taiwan.