Nullinga Dam & Mareeba Dimbulah Water Supply Scheme DBC

Direct Client: Building Queensland
Services Primary : Business Case
Sector: Water

Background

The business case investigated improving the Mareeba Dimbulah Water Supply Scheme rules and operation, and upgrading the existing Arriga and East Barron Channels. An in-depth analysis of the design and construction of Nullinga Dam was also undertaken.

Following the  Preliminary Business Case submitted in 2017, Aalto was engaged to and author the detailed business case. The preliminary business case found that while some initiatives would potentially stimulate irrigated agriculture in the region, supporting an opportunity for new or expanded agricultural activities, the demand assessment undertaken for the preliminary business case did not identify a compelling demand at that time, and hence, did not identify an urgent requirement for additional water supply.

Aalto’s Role

The Business Case was designed to provide a robust assessment of the opportunities and challenges of increasing water availability in support of potential future agricultural demand in the Mareeba Dimbulah Water Supply Scheme.

Outcomes and Insights

The business case analysis revealed that construction of the proposed Nullinga Dam was neither financially nor economically viable.

The proposed Nullinga Dam site is located in a poor performing catchment requiring a costly build solution. To construct a dam that would meet identified demand would require an extended and costly construction program relative to the volume of water that would be available..

While the business case recommended to not proceed with Nullinga, Aalto worked closely with the proponent and client to ensure alternative options, previously discarded, were identified for further action and consideration.