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

49 Figure 28. Temperature profiles for two sites in Ruby Billabong, on common land adjacent to the Douglas-Daly Research Farm. The black traces are for depths of 0.1, 0.5, 1.0, 2.0, 3.0 and 4.0 m; red 5 m; blue 7 m. July 2000. Stratification occurs at 5 m, but with a surface influence evident on the windier (hotter) days. The Thermal Model Model Formulation The model describes the transport of heat downstream by the river flow. The equation to be solved is: + =T t U T x F C Dp (1) where T is river water temperature which is a function of distance along the river, x, and of time, t. U is the river flow speed, is water density, Cp , is the specific heat of water, D is water depth, and F is the flux of heat across the water surface due to evaporation, solar radiation etc. The estimation of F is discussed later. The model allows for the injection of spring water at position xspring with a flow volume of Qspring and of temperature Tspring (Fig. 29). In fact, there are discharges all the way along the river channel from springs and creeks, (Tickell, 2002), but the largest input accounting for ~65% of the total input between Dorisvale and Cattle Creek occurs in the 10km section between river distances 24x = to 33km. We assume that all the spring water is input to the river at the average distance x = 29km and that discharges above and below this distance are uniform along the river. The solution to Eq. 1 was obtained numerically for the river section between Dorisvale and the spring using an upwind differencing scheme (Roache, 1982). The initial condition required for solution in this river section was the temperature linearly interpolated between