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

16 Analysis of Historical Flow Data Data Sources and Quality Control The Northern Territory Department of Lands Planning and Environment provided historical flow data for Dorisvale Gauging Station. The data was an admixture of direct measurements and values estimated from recession curves, which could not be disaggregated. The poor quality of the data required that we apply a series of cross-checks which led to the elimination of data for a number of years: We eliminated data for particular years when there was high and unexplained variability in the daily flow data about the recession trend, suggesting equipment failure; inexplicable departure from reasonable expectation for recession of flow, post flood; inexplicable low variation in daily flows about the recession trend, indicating that the data had been generated rather than measured. In addition, data for any one month that was based on less than 20 days was eliminated from analysis of data by month. Despite these deficiencies, we regard the summary of flow conditions for the Daly River to be reasonably accurate. Caution should be exercised in the interpretation of individual values, such as the minimum low flow, though where possible, we have cross-checked these figures with DIPE staff. Approaches to improving the quality of dry-season flow monitoring for the Daly have been included among our recommendations. Rainfall data were obtained from the Douglas-Daly Research Farm for the period 1968-97. Rainfall figures for Katherine (DR014902) were obtained from the Bureau of Meteorology for the period 1884-2000. Rainfall The Daly River is in the wet-dry tropics of the Northern Territory. As such it experiences the extremes of high rainfall during the monsoonal wet seasons and the near absence of rainfall in the intervening dry seasons (Figure 2). The wet season extends from December to March inclusive under the influence of the tropical monsoon, whereas virtually no rain is received in the dry season, which extends from June through September. April-May and October-November are the wet-dry and drywet transitional months, respectively. Notwithstanding the general utility of these seasonal definitions, rainfall is highly variable within and across years (Figures 2 and 3) in the quantity that falls and its timing. It can be argued that there is no such thing as a typical year (Taylor and Tulloch, 1985).