Oral Presentation 9th Australian Stream Management Conference 2018

Warrego Hydrology: what is, what was and what might have been. (#65)

Paul Frazier 1 , Mark Southwell 2 , Andrew Herron 2
  1. 2rog Consulting, Armidale, NSW, Australia
  2. Ecological, Armidale, NSW

The Commonwealth Environmental Water Office Long Term Intervention Monitoring Project monitors the contribution of Commonwealth environmental water (CEW) in the Murray-Darling Basin.  There are seven selected areas that are the focus of much of the on-ground monitoring effort.  The Junction of the Warrego and Darling Rivers selected area is set primarily at the confluence of the Warrego and Darling Rivers on the former Toorale Property.  

The Warrego River is not regulated by large headwater dams; in-stream structures (dams) store relatively small amounts of water and in some cases can be used to divert water into floodplain wetlands.  The river is ephemeral with no-flows (0 ML/day) occurring for over 25% of the time.  CEW is not exactly delivered into this system, rather it is not abstracted and the retained water can be managed to either flow to the Darling or onto the extensive Warrego Western Floodplain. 

This presentation details hydrodynamic models developed for the Warrego channel and Western Floodplain.  An examination of measured flows and inundation over a 3 year period is compared to flow scenarios that might have occurred under irrigation or grazing focus scenarios prior to the Commonwealth acquiring the property and its water licences.  These alternate or counter-factual scenarios provide an important basis for understanding the contribution to CEW on the environment.

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