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Sinclair Knight Merz - Scoping Study Commonwealth Use of Private Water Storages in the Northern Murray Darling Basin

Sinclair Knight Merz, 2012

The Commonwealth Environmental Water Office commissioned this report in order to receive information which it can draw from to support the functions of the Commonwealth Environmental Water Holder. This report scopes a number of potential future opportunities for Commonwealth and private partnerships to support Commonwealth environmental water delivery. The views in this consultancy report do not necessarily represent the views of the Commonwealth Environmental Water Office. The Commonwealth Environmental Water Office is not looking to pursue the options identified in this scoping study in the short-term. Any decision to explore this work further will be undertaken in consultation with stakeholders, including relevant local and community groups.

Introduction

Commonwealth Environmental Water was established under the Water Act 2007 (the Act) to manage environmental water and water holdings acquired by the Commonwealth. Under the Act, Commonwealth environmental water and water holdings are managed to protect or restore the environmental assets of the Murray-Darling Basin (MDB), and other areas outside the Basin where the Commonwealth holds water and water holdings.

The Commonwealth Environmental Water Office uses a number of mechanisms to ensure the Commonwealth’s environmental water portfolio can best meet environmental needs. These mechanisms include the use of water trade and carryover. However, much of the flexibility to delivery water is derived from the Commonwealth’s ability to store water within headwater dams and call the required volumes to specific locations at a time which best meets environmental need. In the largely unregulated northern catchments of the MDB this option is more limited or not available at all. This is because water rights and water infrastructure in these catchments are based on opportunistic access to water when certain flow conditions are met. These conditions are often linked to flow rates specified at certain points on a river system. Irrigators in these areas typically have high capacity off-takes and large on-farm dams (called ‘ring tanks’ or ‘turkey nest’ dams) to harvest and store both river and overland flows. These features of unregulated catchments influence how, and when, environmental watering is undertaken.

The Commonwealth Environmental Water Office has identified some opportunities where it may be advantageous for the Commonwealth to use private storages and other water infrastructure to store and deliver Commonwealth environmental water. The use of private storages and water infrastructure may provide flexibility when watering assets that are located far from the main river channel, or where there is no public infrastructure or delivery arrangement in place.

This scoping report explores the potential for use of private storages and water infrastructure in the northern MDB. The objectives of the study were to:

  • discuss how the Commonwealth could use private storage and water infrastructure to assist in delivering Commonwealth environmental water, and the potential benefits and risks associated with this use, and
  • provide a preliminary assessment of the environmental utility and operational flexibility that private storage and delivery of Commonwealth environmental water might provide.

The study focused on three pilot catchments in Queensland and New South Wales – the Condamine-Balonne, Border Rivers and Namoi. The scoping report is structured such that opportunities to use private storages and water infrastructure are discussed in separate chapters for each pilot catchment.