10 December, 2025
Industries
Client
Sunwater
Disciplines
The Dawson Valley Water Supply Scheme has exhibited significant growth in agricultural water use over the past five years, driven by the increased uptake of water entitlements by largescale cotton growers. The significant demand for the temporary leases of the Strategic Water Infrastructure Reserve, administered by the Queensland Government, is evidence of the significant demand that exists in the scheme and the opportunity for additional water supply to generate significant direct and flow-on economic benefits.
The scheme is also comprised of several industrial users, including several coal mining companies in the southern Bowen Basin and Queensland Nitrates, an ammonium nitrate producer. Synergies was engaged by Sunwater to undertake a comprehensive demand assessment for the Dawson Valley WSS to underpin the OA, in addition to assessing the economic feasibility of the shortlisted option, which focused on supplying water to facilitate the growth of largescale cotton enterprises in the Dawson Valley.
Synergies developed a probabilistic water demand model for the Dawson Valley WSS, informed by extensive consultation with stakeholders in the agricultural, industrial, and urban water sectors. The model underpinned the cost-benefit analysis of the shortlisted options, which was undertaken in accordance with the Queensland Government’s Business Case Development Framework and was subject to formal Gateway Review processes.
Sunwater obtained government funding to undertake an Options Analysis for enhancing water supply in the Dawson Valley WSS. The key driver of the project was the significant uptake of the temporary lease of the Strategic Water Infrastructure Reserve, which was released by the Queensland Government as three-year temporary leases.
Synergies was engaged to undertake two components of the OA – the water demand assessment as part of the Service Need Assessment and the economic analysis of the shortlisted options.
The agricultural water demand profile in the Dawson Valley WSS is dominated by cotton production, in addition to other broadacre crops grown in rotation with cotton, while the industrial demand includes a coal mine and an ammonia nitrate plant. The scheme also supplies small townships in the Dawson Valley.
The drivers included in the demand model focused on the available land for development of largescale irrigated cotton production in the Dawson Valley and the impact of climate change on future water requirements for cotton production. The industrial demand focused on the long-term outlook for coal production and exports in the Blackwater system.
The water demand assessment required the development of a model that reflected the range of demand drivers and accommodated the considerable uncertainty that exists in relation to these factors over the 30-year evaluation period. A robust demand assessment is critical not only to define the service need for the OA, but also to underpin the shortlisting of project options and the economic and financial analysis of the shortlisted options in the OA.
A probabilistic water demand model was developed incorporating all agricultural and industrial water demands in the Dawson Valley WSS. Synergies undertook extensive desktop and market analysis, which was supplemented by consultation with stakeholders. The analysis and consultation informed firstly, the identification of key drivers for each demand segment, and secondly, the setting of appropriate parameter values in developing the model.
Most likely, low, and high estimates were identified for each demand driver, which were combined to develop the probabilistic model. The model provides demand profiles – most likely, P10, and P90 – for aggregate water demand and for individual demand segments. This not only provides a robust picture of the central or most likely demand but, using Monte Carlo simulation, provides a comprehensive picture of the potential range of future water demand profiles, reflecting the uncertainty that exists in relation to the key demand drivers.
Infrastructure options were then shortlisted having regard to the outcomes from the demand assessment and other preliminary information.
The shortlisted options were then subject to an assessment of economic feasibility, under the cost-benefit analysis approach. Synergies undertook the economic analysis, with the benefit quantification informed by scheme-specific, farm-level financial models for key crops in the scheme. These models were developed with direct input from irrigators in the scheme to ensure the quantification of accurate economic benefits. A comprehensive economic analysis report was developed, and chapter inputs were drafted for the OA. Synergies also assisted with price modelling to inform the financial analysis of the options.
Our comprehensive and robust assessment of long-term water demand in the Dawson Valley WSS provided Sunwater with a robust basis for undertaking comparative assessments of the long list of infrastructure options, in addition to ensuring the robust quantification of economic benefits for the shortlisted options. The demand modelling and economic analysis was provided a positive appraisal by the Gateway Review Panel.
In addition to ensuring the completion of a robust Options Analysis for the Dawson Valley WSS, the probabilistic demand assessment also provides Sunwater with valuable information regarding the long-term outlook for several of its key customer bases in Central Queensland. The approach to developing the model enables the key parameters to be updated over time, providing Sunwater with a key resource to inform infrastructure planning in Central Queensland over the long term.
To find out more about this project and how Synergies can assist you, send an email to: contactus@synergies.com.au