Territory Stories

East Alligator district centre water supply assessment : Kakadu National Park

Details:

Title

East Alligator district centre water supply assessment : Kakadu National Park

Other title

D . Pidsley

Creator

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

Collection

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

Date

1991-02-26

Description

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

Notes

Date:1991

Language

English

Subject

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

Darwin

Series

Technical Report ; 26/1991

Format

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

File type

application/pdf.

Copyright owner

Check within Publication or with content Publisher.

Parent handle

https://hdl.handle.net/10070/229020

Citation address

https://hdl.handle.net/10070/673451

Page content

Technical Report WRD91026 Viewed at 15:07:48 on 29/07/2010 Page 26 of 107. RN OR For a Langelier Saturation Index of less than - 2.0 the water will tend to cause serious corrosion. For a Ryznar Stability Index of greater than +9.0, corrosion tends to be intolerable. Values of these indices were calculated for water samples taken from bores at East Alligator and these values are shovTn in Table 2.5. TABLE 2.5: CORROSIVITY OF WATER SUPPLY AT EAST ALLIGATOR DATE TOTAL TOTAL TOTAL pH pHs LANGELIER RYZNAR SAMPLED DISSOLVED HARDNESS ALKALINITY SATURATION STABILITY LOCATION SOLIDS as GaG03 as GaG0 3 INDEX INDEX (mg/L) (mg!L) (mg/L) pH-pHs 2pHs-pH 8918 Sl89 25 21 17 6.1 9.1 -3.0 12.2 20480 12/90 170 106 24 6. 1 8.3 -2.2 10.6 20637 5/81 63 23 15 6.5 9.2 -2.7 11. 9 23449 5/89 10 3 (] 4.4 '>11. 2 <-6.8 >18.0 23450 12/90 30 4 2 4.9 10.8 -5.9 16.6 Kitchen tap 12/90 25 4 1 5.1 11. 1 -6.0 17.0 house 6 These indices show the groundwater supply to be very corrosive, as is most of the groundwaters in the Top End of the Northern Territory (Reference 5). This reference is appended to this report and forms Appendix 7. There is an in line pH correction system installed at the inlet to the 49 kL and 45 kL tanks for water being pumped from RN 23449 and 23450. The line from RN 20480 does not direct water through this unit, but straight into the 49 kL tank. This pH correction unit doses the water with liquid sodium hydroxide and requires frequent maintenance to work effect! vely. This unit was not working on 4 December 1990, as shown by the water analysis on the sample taken from House 6, shown in Table 2.5. However, the pH r~!adings displayed on the monitor of the unit indicated that it was working. It would appear that this is not an unusual situation for this unit {see other sample analyses from the distribution system in Appendix 2 j . Generally a 005MJ