Flood Warning and Damages in Alice Springs: Part 1 Executive Summary. Part 2 Tangible Damages Part 3 Intangible Damages & Emergency Procedures
Handmer, John; Smith, D. I.; Greenaway, Mark
E-Publications; E-Books; PublicationNT; Report ; 53/1989
1989-04-01
Made available via the Publications (Legal Deposit) Act 2004 (NT).
Date:1989-04
English
Power and Water Authority
Alice Springs
Report ; 53/1989
application/pdf.
Check within Publication or with content Publisher.
https://hdl.handle.net/10070/228902
https://hdl.handle.net/10070/673596
Technical Report WRA89053 Viewed at 03:02:00 on 18/02/2010 Page 122 of 139. I I I I I I I I I I I I I I I I I I I I The pool of water would be used to kcep the clay core of the dam moist. Water would be pumped into the top of the upstream sand filter with a small solar powered pump and allowed to trickle down the tilter. The height of water permanently stored against the main dam would be 9.0m compared with 22.0m for the" full" dam option. Instrumentation would be incorporated into the dam to detect changes in moisture content in the core. Sediment Traps Sediment traps would be provided on the Todd River and Colyer Creek as outlined in the EIS. Sediment Carting The proposal outlined in the EIS to cart sand and gravel deposited in the sediment traps and place it in the low flow section of the spillway channel excavation remains. Because of the greater attenuation of small to medium sizes floods, the quantity of sand carted is estimated to be significantly less than for the "full" dam, ie. average of 8,500m3fyear rather than 12,OOOm'/year. Actual rates for placement of replenishment sand will depend on the monitoring of bed levels within the river. . Access Roads Gravel paved access roads would be provided betwcen the sediment traps and the Stuart Highway and between the Stuart Highway and the spillway channel excavation to allow for sand replenishment. Construction , Construction would be similar to that outlined in the EIS. The principal differences being: effective tlood mitigation for Alice Springs would be in place by the end of 1992, providing further consultations with Custodians proceed satisfactorily. The order of construction would be resolved following acceptance and may vary from that included in the EIS to suit variability in tlood risk throughout the year. vegetation and trees wi!! no longer be cleared out of the inundated area. a new source of filter sand will be required, as the source in the Todd river immediately upstream of the dam wall may not be available for use. At the time of writing an alternative source had not been finalised. 4