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East Alligator district centre water supply assessment : Kakadu National Park



East Alligator district centre water supply assessment : Kakadu National Park

Other title

D . Pidsley


Jamieson, M.; Pidsley, D.; Paiva, Jerome


E-Publications; E-Books; PublicationNT; Technical Report ; 26/1991




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






Water-supply -- Northern Territory -- Kakadu National Park; Groundwater -- Northern Territory -- Kakadu National Park; Kakadu National Park (N.T.)

Publisher name

Power and Water Authority

Place of publication



Technical Report ; 26/1991


1 v. : ill., maps ; 30 cm.

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Technical Report WRD91026 Viewed at 15:07:48 on 29/07/2010 Page 41 of 107. 4.5 DETERMINATION OF AOUIFER PROPERTIES From analysis of data taken from pump tests performed on the bores in the fractured sandstone (see Appendix 4) the following aquifer and bore properties were determined. Transmissivity = Confined Storage Coefficient = Drawdown due to >vell effects = 30 m2/day 3 x 10- 5 0. 11Q2 (Q in L/sec) Geophysics and drilling conducted to date indicate that the fractured rock aquifer has a width of about 200 m (see Diagram 6) . No work has been done to establish the length of this aquifer, but it may exist over much of the length of the Bulman fault. It is usual for fractured rock aquifers to act similarly to unconfined aquiferJ3 in the long term. A dolomite aquifer in the Nanambu Creek regj,on (near Jabiru) is reported to have had a storage coefficient of around 10- 3 , but its response to long term pumping indicated it was acting like an unconfined aquifer with specific yield of 2 to 5% (Reference 7). A pumping water level of 18 m depth was measured in RN 23449 and RN 23450 on 25 October 1990. With a transmissivity of 30 m2 /day, a specific yield of 1% would be required for water levels to drop to 18 m depth (at the estimated extraction rate of 122 kL/day) in 180 days. A specific yield of 1% is considered as appropriate to describe the long term behaviour of this aquifer. 4.6 SUSTAINABL:;; YIELD OF PRESENT BOREFIELD Assuming that the fractured rock aquifer at East Alligator is a I strip aqui fer I (ie a rectangular strip of aquifer material bounded on two sides by an impermeable material), and using the properties from Section 4.5, the sustainable yield of the aquifer was estimated using a flow net analysis. OOSMJ