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
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
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
Northern Territory Government
57/2002; National River health program
75 pages ; 30 cm
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
25 Rises and Falls The number of days in which a fall in flow was recorded dominated the number of days in which a rise in flow was recorded in all months (Figure 11). This reflects the episodic nature of the rises compared with the more graduate decline in flows after a rise. It is therefore not possible to easily define the transition between high-flow and low-flow seasonal conditions using the ratio of number of rises to falls in a month. A better indication is given by when the number of days experiencing a rise exceeds the number of days of steady state (change in flow < 1 cumec per day). This index measures the relative frequency of episodic rises against the frequency of steady state conditions. The transitional month between high and low-flow conditions can be defined as the month in which the frequency of rises first becomes dominated by the frequency of steady state conditions. Similarly, the transitional month between low and high-flow conditions can be defined as the month in which the frequency of rises first comes to dominate by the frequency of steady state conditions. When averaged across years for each month, the transitional months are April and December respectively (Figure 11). Figure 11. Frequency of occurrence daily falls in flow (-), steady state conditions (0), and rises in flow (+) at the Dorisvale gauging station (G8140067), Daly River, Northern Territory. Steady state flow occurs when the daily change in flow remains less than one cumec. Data from months where there were less than 20 gauged days were excluded. Figure 10. Coefficient of Variation (CV) in flow across months for the Dorisvale gauging station (G8140067), Daly River, Northern Territory. Box diagrams show the means, approximate 95% confidence limits, and the range in CV for each month. Data from months where there were less than 20 gauged days were excluded.