1.5.1 Current water accounts

Summary

Current coal and coal seam gas (CSG) development and exploration, which may impact water resources are primarily located in an area to the west of the town of Casino in the Richmond river basin. The surface water accounts were only determined for the Richmond river basin as this is the area being modelled. The Richmond river basin includes the Richmond and Wilsons rivers with small contributions from Eden Creek and Shannon Brook. There are two main reservoirs (Toonumbar and Rocky Lake) and a few small dams and weirs that supply water to agricultural, domestic and municipal users. The combined storage volume in the main reservoirs is 25 GL. The main surface water resource of the Richmond river basin is the Richmond River. In the Richmond river basin, permits to extract surface water amount to 99.8 GL/year.

The groundwater accounts were also restricted to the model domain of the numerical groundwater model, whose boundaries were constrained by knowledge of the geology, previous studies in the Clarence-Moreton Basin and Surat Basin, and common modeling practise. The analysis lacks measurement of actual groundwater usage, hence, it was estimated using the allocation data in the NSW state groundwater database (Bioregional Assessment Programme, Dataset 2 in Section 1.5.1.2). Those estimates indicated that 88.1% of the bores have allocations of less than or equal to 5 ML/year. Of the estimated water usage, 49.5% and 42% is allocated for irrigation and domestic/stock bores, respectively. The Richmond River alluvium and Lamington Volcanics represent the two main groundwater supply aquifers with much smaller allocations in the Grafton Formation and the Walloon Coal Measures. The NSW water sharing plans are developed to preserve surface water and groundwater by balancing the competing demands of different types of water usages. They are defined based on surface river basins and groundwater systems.

Last updated:
9 September 2016