HR: 0800h
AN: H11C-0313    [Abstracts]
TI: An Additional Calibration Target And Particle Tracking Mechanism To Improve Groundwater Flow Simulation In A Coastal Wetlands System
AU: * Reynolds, D A
EM: reynolds@cwr.uwa.edu.au
AF: Centre for Water Research, University of Western Australia, 35 Stirling Highway,Crawley, Perth, WA 6009 Australia
AU: Marimuthu, S
EM: marimuth@cwr.uwa.edu.au
AF: Centre for Water Research, University of Western Australia, 35 Stirling Highway,Crawley, Perth, WA 6009 Australia
AB: A conceptual model of a Coastal Wetlands system that has been developed using hydraulic, chemical and stable isotopic data has been used as the basis to develop a groundwater flow model using the finite element numerical code (FEFLOW). The model will be utilised to identify the role of groundwater within the system and assist in the mitigation of the effects of the non-seasonal floods. The dynamics of water exchange between surface water and groundwater within coastal wetlands system is of central importance for the management of the wetlands. The system to be modelled 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. The simulation of groundwater flow requires detailed knowledge of aquifer parameters and their spatial distribution, however, the availability of information is limited by the point measurements at the borehole locations. 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 by inserting a large number of particles directly beneath and adjacent to the lakes. The analysis was able to delineate the connectivity between the lakes and the flow path. The isotopic analysis of the system has identified all of the water sources that potentially flow through the system and the continual enrichment of isotopic concentrations is quite visible along the northeast southwest transect. The data set provides a means for calibrating a detailed transport model and a good match between observed and simulated temporal variations along the transect indicates that the model closely simulated the dynamic of water exchange between the lakes and groundwater within the system. It is of particular interest to this study that utilization of a model calibrated entirely on hydraulic data was unable to capture the subtleties of the complex, inter-linked system.
DE: 3210 Modeling
DE: 1829 Groundwater hydrology
DE: 1831 Groundwater quality
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting