Territory Stories

Alice Springs town basin, review 2003



Alice Springs town basin, review 2003


Read, R. E.


E-Publications; E-Books; PublicationNT; Report ; no. 42/2003




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





Publisher name

Department of Infrastructure, Planning and Environment

Place of publication

Alice Springs


Report ; no. 42/2003

File type


Copyright owner

Check within Publication or with content Publisher.

Parent handle


Citation address


Page content

January 2000 to June 2000 80 mm. SKMs (2001) estimate is doubtful. Diffuse recharge appears to occur in the rare periods of heavy rainfall. It has been increased by changes due to urbanisation, such as: The establishment of heavily irrigated grass areas and landscaped gardens, especially if cultivated. Concentration of run-off from paved areas and roofs. Leakage from water reticulation and sewers. The construction of trenches for sewerage and water reticulation produces zones with permeability much higher than the surrounding undisturbed rock (Sharp & Krothe, 2002). This can lead to higher vertical permeability and hence higher diffuse recharge. This has been suggested as a mechanism for contaminating the alluvial aquifer with highly saline water from weathered bedrock, but calculations presented by Rooke (1992) show that it is unlikely to be significant. Diffuse recharge is difficult to relate to rainfall, as periods of sufficiently high rainfall are rare, and always coincide with major river recharge. Local Recharge This component has not been described in previous studies. It was identified in water balance studies for monitoring periods with no river flow (Appendix G). Significant recharge was identified in periods with rain and no river flow at the Anzac gauge. This recharge is described by equations R= 2.24 (F-10), F>10 R=0, F<10 Where R is recharge in ML in periods of no river flow. F is rainfall in mm. Most of this recharge is from storm drains that discharge into the Todd, and is not diffuse recharge (Appendix G). This local recharge appears to average about 200 ML/year (Appendix G). This estimate relates to the state of development of the town from 1996 to 2000. It would not have applied prior to the construction of the present system of storm drains. Recharge from sewers and water pipes PWC are not able to account for 2000 ML/year pumped into the town area. Much of this may be due to problems with meters, but if say one quarter of it is leakage this would represent a large increase in recharge to the Town Basin. Sharp and Krothe (2002) presented data showing that leakage from water mains ranges from 8 to 50%. The study in Appendix G did not identify any constant recharge component. Either recharge from this source is almost exactly balanced by outflow to sewers or, more likely, it is insignificant. This does not necessarily mean that leakage is not occurring. Most of the town has well established trees and shrubs that could easily evapotranspire water from a leak. However the water balance studies of periods with no river flow suggest that the net effect is insignificant (Appendix G). 41