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

34 It is inappropriate to simply remove 10% of the flows from each control point, because the relationship between flow at Dorisvale and flow at Oolloo is linear but does not pass through the origin it is not a simple proportional relationship. Taking 10% off the flow at each control point breaks this relationship, and this becomes apparent at the extremes for extraction when the flows at Dorisvale and Oolloo are no longer in sync. Fo Flow at Oolloo in year of study Fc Flow at Dorisvale in year of study Intercept for relationship between Fo and Fc Slope of relationship between Fo and Fc r percentage reduction in flow at Oolloo Crossing r reduction in flow at Oolloo in cumecs for reduction r% Let oc FF += Reduce flow at Oolloo by r cumecs so that roo FF = ' rcoc FFF =+= '' So a reduction of r cumecs at Oolloo will correspond to a reduction of r cumecs at Dorisvale. The drop in flow from Dorisvale to Oolloo after a reduction of r% at Ooloo will be )('' rcroco FFFFr == Take two adjacent control points. Reduction in flow between the two in 2001 was observed to be Do , then its reduction inflow after r% is given by r o o r D D = These incremental reductions can be applied from Dorisvale to Cattle Creek, in the knowledge that the flow at Oolloo will correspond to a reduction of r%. Results of this analysis are shown in (Table 5). Table 5. Locations where flow changed in the Daly River between Dorisvale Crossing and Cattle Creek. Change in flow at June-01 are measured whereas flows between 10% and 90% are estimated based on the calculations above.