Surface water numerical modelling

Surface water modelling in the Hunter subregion is achieved using a combination of rainfall-runoff modelling and river system modelling. The rainfall-runoff model is the Australian Water Resources Assessment (AWRA) landscape model (AWRA-L) (Viney et al., 2015). This model is applied using the regional calibration scheme described in companion submethodology M06 (as listed in Table 1) for surface water modelling (Viney, 2016).

The Hunter river basin covers a large area and comprises both regulated and unregulated river sections. Downstream of Glenbawn Dam and Glennies Creek Dam, the Hunter River and Glennies Creek are regulated. This means that in addition to inflows from unregulated tributaries and groundwater, river flow in these reaches reflects releases of water stored in the dams to meet the needs of downstream users, including the environment. These characteristics dictate that a river model is required to translate streamflows generated by the landscape model. This is done using the AWRA river model (AWRA-R) (Dutta et al., 2015), an overview of which is provided in Viney (2016).

The exception here is for the Wyong River in the Macquarie-Tuggerah lakes basin, which is smaller and unregulated and no river modelling is applied. In this catchment, the salient features of streamflow can be simulated solely with the rainfall-runoff model. Gridded output from AWRA-L is accumulated to the model nodes without any lagged routing.

The regulated section of the Hunter River from Glenbawn Dam to Singleton is the focus of the Hunter River Salinity Trading Scheme (HRSTS), which was established to manage discharges of water to the Hunter River by the mining and power generation sectors to minimise water quality impacts. New Hunter-specific functionality has been added to AWRA-R to mimic the effects of the HRSTS. Details of this part of the model are given in companion product 2.1-2.2 for the Hunter subregion (Herron et al., 2018a).

In all other respects, the surface water modelling in the Hunter subregion follows the methodology set out in companion submethodology M06 (as listed in Table 1) for surface water modelling (Viney, 2016).

Last updated:
18 January 2019
Thumbnail of the Hunter subregion

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