Territory Stories

End of Wet Season Stream Flow Measurements, Roper River, May 2014

Details:

Title

End of Wet Season Stream Flow Measurements, Roper River, May 2014

Creator

Kerle, Errol; Waugh, Peter; Northern Territory. Department of Land Resource Management

Collection

E-Publications; E-Books; PublicationNT; Aug-14

Date

2014-06-01

Location

Roper River

Description

Early dry season snapshot measurements were taken on the Roper River to establish water quality and quantity conditions at commencement of baseflow conditions. The snapshot measurements are used to: 1. Refine and calibrate the hydrological model used to assess resource availability and allocations. 2. Better define aquifer recharge/discharge zones along the river, and 3. Provide a dataset of comparable flow and water quality measurements at identical periods in the annual water cycle.

Notes

Made available via the Publications (Legal Deposit) Act 2004 (NT)

Table of contents

Summary -- Aim -- Introduction -- Observations -- Discussion -- Conclusion -- Recommendations -- References

Language

English

Subject

End of Wet Season Stream Flow Measurement

Publisher name

Northern Territory Government

Place of publication

Palmerston

Series

Aug-14

Format

24 pages : illustrations, colour maps ; 30 cm.

File type

application/pdf

ISBN

1743500637; 9781743500637

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/10070/260106

Citation address

https://hdl.handle.net/10070/492338

Page content

4 Summary Stream flow and water quality measurements were conducted in late May to establish early dry season baseflow conditions in the Roper River. Post wet season runoff, all flows within the Roper River discharge from the Mataranka Tindall Limestone Aquifer. Consistent with previous measurements, stream flow steadily increased as the river passes through the aquifer, with a maximum recorded flow of 7.9m3/s on the eastern boundary. Continuing downstream, a gradual reduction in flows is observed with 4.8m3/s measured at Red Rock, approximately 170km downstream from the aquifer boundary. May 2014 flow measurements continue a trend of decreasing early dry season flows observed since 2011. Measured flows were below the long-term average (1967 2014) for the first time since 1997. Significant variation in measured water quality parameters is representative of two distinct regional groundwater flow regimes that exist within the aquifer. A third localised flow regime also contributes its distinct water quality signature to overall riverine chemical balances. Measured parameters are generally more neutral than those collected during the October 2013 snapshot measurements, indicating dilution through aquifer recharge over the wet season and a reduced residence period within the aquifer prior to discharge. Biological as well as physical processes in the river also affect its chemistry. Overall chemical balances indicate a healthy, chemically balanced river system. Aim Early dry season snapshot measurements were taken on the Roper River to establish water quality and quantity conditions at commencement of baseflow conditions.. The snapshot measurements are used to: 1. Refine and calibrate the hydrological model used to assess resource availability and allocations. 2. Better define aquifer recharge/discharge zones along the river, and 3. Provide a dataset of comparable flow and water quality measurements at identical periods in the annual water cycle. Introduction Rising in the Mataranka area of the Northern Territory, the Roper River flows eastwards for 250 kilometres before discharging into the Gulf of Carpentaria. This study looks at the early dry season flow profile of the river with specific focus on the headwaters of the river where it passes over the carbonate rocks of the Palaeozoic aged Daly Basin. The basal formation of the basin - the Tindall Limestone - forms a regional scale fractured and karstic aquifer. The Roper River is one of several main discharge sites for the aquifer. Groundwater discharges into the river as it cuts through the unconfined aquifer and maintains stream flow throughout the dry season. A draft Water Allocation Plan (WAP) has been developed for the Tindall Limestone (Mataranka) aquifer to ensure water allocation and management is undertaken in a sustainable manner, to ensure equitable use of increasingly scarce water resources into the future. A monitoring program developed for the WAP ensures that models used to predict


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