HR: 0800h
AN: H11D-1282    [Abstracts]
TI: Deuterium Concentration And Flow Path Analysis As Additional Calibration Targets To Calibrate Groundwater Flow Simulation In A Coastal Wetlands System
AU: * Marimuthu, S
EM: marimuth@cwr.uwa.edu.au
AF: Centre for Water Research, The University of Western Australia 35 Stirling Highway, Crawley, Perth, WA 6009 Australia
AU: Reynold, D A
EM: reynolds@cwr.uwa.edu.au
AF: Centre for Water Research, The University of Western Australia 35 Stirling Highway, Crawley, Perth, WA 6009 Australia
AB: A conceptual model of a Coastal Wetlands system (Lake Warden wetlands system, Western Australia) has been developed using hydraulic, chemical and stable isotopic data and this has been used as the basis to develop a groundwater flow model using the finite element numerical code (FEFLOW). The model was utilised to identify the role of groundwater within the system and assist in the mitigation of the effects of the non-seasonal floods. The system to be modeled is complex in the sense that the surface water and groundwater within the wetlands system show varying salinity and isotopic composition over short distances and time frames. As a first step, the flow model was calibrated to observed groundwater levels since 2001 for both steady state and transient stresses. A particle tracking analysis was conducted to test the source areas of water discharging to the lakes within the wetlands system. The analysis was able to delineate the connectivity between the lakes in the wetland and the flow path. The isotopic analysis (deuterium concentration) of the system has identified all of the water sources that flow through the system. The continual enrichment of isotopic concentrations is quite visible along a northeast-southwest transect and the data set provides a means for calibrating a detailed transport model. The study employed a novel method to incorporate the varying deuterium concentration of the water bodies directly into a transport model and a good match between observed and simulated temporal variations along the transect indicates that the model closely simulated the dynamics of water exchange between the lakes and groundwater within the system. Utilization of deuterium as a calibration target has improved and enhanced the confidence of the overall model calibration of a complex, inter-linked system such as Lake Warden wetlands system.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1869 Stochastic hydrology
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: Fall Meeting 2005