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).
Department of Infrastructure, Planning and Environment
Report ; no. 42/2003
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5.3.2 History of the water table Figure 7 shows the history of water levels in the Town Basin. The first section of the hydrograph in the early 50s represents a period of moderate withdrawal under more or less normal rainfall. In the 1950s and early 1960s drawdowns accelerated as production increased with a growing population (Figure 8 ). In the mid 60s water levels began to rise in response to the phasing out of pumping from the Town Basin (Figure 9 ) in favour of the Mereenie Sandstone aquifer at Roe Creek. There was a dramatic rise following the very wet year of 1974 and then fluctuations with seasonal conditions. In total water levels have fluctuated by about 9 m. Water levels have been high from 1975 onwards. The large recharge event of 1974 was in a period of rapid increase in population and water consumption. It appears that run-off from roofs and paved areas and possibly leachate from heavily irrigated grassed areas, have combined to keep water tables high ever since. Leaking sewers and water reticulation have also been suggested as sources of extra recharge, but there is little hard evidence for this. Rates of loss from storage in periods of no recharge were examined in Appendix G. It was found that in periods of no recharge losses from the Town Basin not due to pumping and the difference between inflow and outflow were proportional to evapotranspiration. Natural losses from the basin in periods of no recharge are estimated as an average of 173 ML/year, corresponding to a rate of decline of about 0.3 m/year. Figure 10 and Figure 11 and show approximate water levels below surface at about the highest and lowest points in the period of record. 1960 1970 1980 1990 2000 12 10 8 6 4 2 D ep th b el ow m ea su rin g po in t Figure 7 Hydrograph of RN 5825 18