Territory Stories

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

Details:

Title

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

Creator

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

Collection

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

Date

2002-11-20

Location

Daly River

Abstract

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.

Notes

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

Language

English

Subject

Environmental Flows; Modelling; Biota

Publisher name

Northern Territory Government

Place of publication

Palmerston

Edition

Final Report

Series

57/2002; National River health program

Format

75 pages ; 30 cm

File type

application/pdf

Use

Attribution International 4.0 (CC BY 4.0)

Copyright owner

Northern Territory Government

License

https://creativecommons.org/licenses/by/4.0/

Parent handle

https://hdl.handle.net/10070/885434

Citation address

https://hdl.handle.net/10070/885435

Page content

24 Coefficient of Variation The range of flows experienced in a given month is considerable, especially under high flow conditions (Figure 8). The coefficient of variation (CV) in the mean monthly flow across years is a measure of predictability of flow conditions. As expected, conditions are highly predictable in the dry season months of May to October, being most predictable in September (Figure 9). The bimodal distribution in the CV (modes in January and March) reflects the greater certainty of high flow conditions in February than in the two months spanning February by virtue of uncertainty in the timing of peak flows (Figure 6). Variation in flow within months showed a similar pattern, with flows being relatively least variable in the months of May through September, and most variable in the remaining months (Figure 10). For a given month, the CV itself varied considerably, especially in the months of October through to the following April. Again this reflects the unpredictability of high flows compared to that of low flows, within particular months. Figure 9. Coefficient of Variation (CV) in mean monthly flow for the Dorisvale gauging station (G8140067), Daly River, Northern Territory. Data from months where there were less than 20 gauged days were excluded. Figure 8. Range in mean monthly flows on a log scale for the Dorisvale gauging station (G8140067), Daly River, Northern Territory. The line shows the median flow; crossbars, the mean. Data from months where there were less than 20 gauged days were excluded.