Territory Stories

Modelling dry season flows and predicting the impact of water extraction of flagship species



Modelling dry season flows and predicting the impact of water extraction of flagship species


Georges, Aurthur; Webster, Ian; Guarino, Fiorenzo; Jolly, Peter; Thoms, Martin; Doody, Sean; CRC for Freshwater Ecology (Australia); University of Canberra. Applied Ecology Research Group


E-Publications; E-Books; PublicationNT; 57/2002; National River health program




Daly River


The aim of this project is to contribute to recommendations on environmental flows to ensure that they are consistent with maintaining the biota of the Daly River, given competing demands of agriculture, recreation and tourism, conservation and Aboriginal culture. Our focus is on flow, connectivity and water temperatures.


Made available by via Publications (Legal Deposit) Act 2004 (NT); Submitted to the Northern Territory. Department of Infrastructure Planning and Environment

Table of contents

1. Project Details -- 2. Executive Summary -- 3. Interpretation of the Brief -- 4. Variation of the Brief -- 5. Background -- 6. The Daly Drainage -- 7. The Pig-nosed turtle -- 8. Analysis of Historical Flow Data -- 9. Analysis of Contemporary Flow Data -- 10. Modelling Flow Reduction -- 11. Water Temperature Versus Flow -- 12. Impact on Flagship Species -- 13. References




Environmental Flows; Modelling; Biota

Publisher name

Northern Territory Government

Place of publication



Final Report


57/2002; National River health program


75 pages ; 30 cm

File type



Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government



Parent handle


Citation address


Page content

11 Flow Magnitude related to connectivity, but in addition, many species are likely to depend directly on flow and related physicochemical attributes (e.g. Dissolved Oxygen). Flow Timing timing of flows is likely to be a cue for many species in determining the appropriate timing of reproductive cycles and behaviours. Water Clarity -- the Daly River is a clear water river in the dry season. Water quality water in the dry season in the Daly River is of mildly basic pH and high conductivity (half a part per thousand). Water Temperature water temperature is likely to be a cue for many species in determining the appropriate timing of reproductive cycles and behaviours, and a driver of production and metabolism. The specific objectives of the project are: (i) To develop flow and temperature models, linked to the population dynamics of an umbrella species, that can be used to predict the likely impact of reduced flow following water extraction for agriculture on ecological values. This will serve as an ongoing management tool, building capacity within the Government Agencies to manage environmental flows. (ii) Input to recommendations on the initial determinations of the best time and appropriate levels of water extraction in order to maintain critical dry-season environmental flow in the Daly. (iii) To develop a standard methodology and series of permanent stations for monitoring flows and water levels, with the ability to separate groundwater and surface flow inputs, to facilitate on-going monitoring of the impact of groundwater extraction in the Daly. This methodology will be transferable to other locations within tropical Australia. The data collected together with the permanent reference stations, will provide a baseline reference set, prior to regulations and substantial extraction, against which the impact of future water extractions can be measured. (iv) To develop information that can be disseminated to increase understanding of the need to maintain environmental flows, and to build constituency support of a rational basis for the determination of water use in the Daly catchment, consistent with sustainability and providing acceptable protection for all commercial and non-commercial values of the region. This will include a well-supported example of the consequential effects of flow alteration on the biology of a key element of the Daly Rivers fauna. Variation of the Brief This project has remained squarely on the three areas of endeavour outlined in the contract (see above) and all milestones were achieved. However, the focus on single pools and subsampled stretches outlined in our original proposal gave way to a focus on a broader scale. This decision was made once the data indicated that the river between Dorisvale Crossing and Cattle Creek (73.7 km) was essentially homogeneous with respect to morphological attributes likely to influence our analysis. Specific variations to the scope outlined in the brief include: