Three dimensional temporal analysis of surface and ground water interactions

Understanding exchanges between surface and ground water systems is critical for good management of water resources. This study uses 3D spatial and temporal analysis of hydrological data to examine the impacts of groundwater irrigation extractions and to map flood recharge zones in two sub-catchments of the Namoi Catchment. In the Maules Creek area the coupling between rainfall, streamflow, groundwater usage and groundwater head is explored. In the Lower Namoi region the difference in groundwater head before and after flooding is mapped in 3D to elucidate recharge pathways. Since the 1960s, as irrigation agriculture expanded in the region, various NSW state government water departments installed more than 550 groundwater monitoring boreholes to observe the impact of the groundwater extractions. At each borehole site from 1 to 7 piezometers were installed and set at different depths in the unconsolidated sediments. Water levels in these boreholes are manually recorded four or more times per year. This is the primary data set used. The major goals of this research are to: •examine the temporal visual correlations between groundwater extractions, streamflow, rainfall and groundwater head; •map in 3D the change in groundwater head due to flood events in order to demarcate hydraulic connections and the pathways of recharge; and •provide catchment management authorities with a visual communication tool for community meetings about water management. Implications: Visual analytical techniques provide a simple but power method to convey the connectivity between various hydrological data sets. The Maules Creek catchment time-lapse presentation demonstrates that groundwater head is correlated to streamflow. Surface and ground water in this region needs to be managed as a connected resource. In the Lower Namoi catchment the unconfined aquifer is coupled to the Namoi River and adjacent floodways. However, the deep aquifer that follows the northern palaeochannel is poorly connected to the Namoi River. This aquifer would require managed aquifer recharge to be replenishe