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 126 of 139. I I I I I I I I I I I I I I I I I I I I 4. ISSUFB, ["I PACTS A]\TI RI\'VIROl\-i\-IENTAL MANAGEJVIENT i [l.itJrlAiil:ig~ti()n Benefits The "partially full" dam would have 1100d mitigation benefits at least equal to those outlined in the EIS for the "full" dam. These include: Reduction in Frequency of Floodin& The "partially full" dam would achieve the objective of mitigating the 1% (100 year) flood from the Todd River so that it docs not cause flooding of the town. Table 2 shows the peak tlows in the river before and after construction of a "partially full" dam. These may be compared with those in Section 3.02 of the E15. TABLE 2 FLOOD l\fiTIGATION PERFORMANCE OF "PARTIALLY FULL" DAM IN ALICE SPRINGS Annual Exceedance Probability Peak Flow Just Upstream of Peak Flow at Wills Terrace (Avera"" Return Interval) Charles River Junction Peak Flow Peak Flow Peak Flow Peak Flow Without With Dam Without With Dam Dam Dam 50% (2 years) 212 I 35 (151) 236 71 (166) I 20% (5 years) 580 93 (302) 657 180 (337) 10% (10 Years) 850 149 (376) 950 263 (435) 1% (100 years) 1450 402 (540) 1680 506 (675) 0.2 % (500 years) 2250 901 (1240) 2574 1006 (1407) Prohablo Maximum Flood 12800 9797 (I 1178) 13959 10635 (12460) Note: Figures in brackets indicate peak now if dam fun to EL658 at start of storm. Increase il] Warning Time In any discussion on warning time, it is important to establish the level at which '.I.dITling time is being measured. 111is was covered at some length in the EI5. For the purposes of this report, warning time is discussed relative to t100ding in the town (ie. river breaking its banks) and relative to smaller flows within the river which may strand people, 8