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
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Power and Water Authority
Report ; 53/1989
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Technical Report WRA89053 Viewed at 03:02:00 on 18/02/2010 Page 33 of 139. I I I I I I I I I I I I I I I I I I I I 3~rcha~ge abut onto those ~hat experienced true river :~:oodi:;q. Again it .15 very difficult to separ-ate the 7:' .. :;J ::,t"ms :;f damage 1 this p::-ob lem \-:as part ly responsible f:) -:7 ~ :::e ;~oble~s in fitting precise limi~s to the 3rea flooded. _~direst losses to a number of government agencies, the :~sts i:lclude those that ~esulted for both river floodi~g ~~d ur~an drainage surcharge. ~he victims of flood damage have, underscandably, ~~tt~e interest in the finer points of such definitions. ~~weve=, for floodplain management they are significant. :Cc:r example, in using the information from the 19-88 flo::js :0 pla~ for future river floods it is important to =~stinguish che differences. Subsequent river floods may, :~ may not, be accompanied by torrential rain and stro~g ~inds. Further, possible mitiqation measures for river ~loodi~g will do little to alleviate urban storm draina=e _-;J::cha~,?e and vice versa. ,\~umbers of properties inundated :he ANTJFLOOD analysis indicates that for the Easter flocd, 225 residential premises had water overground at some pcint :~ the~r g~ounds, a further 62 had g~ollnd heigh~s that :~rres~onded to maximum flood height. Of the 225, wate~ is estimat.ed to have reached overfloor levels for 203, '.,.;,i(::-:' a --.,-~,,-- 25 '-'~h flood -ne'g-t--~ ~vact 1-' ma~-n' ;ng floor ho' -"'t ~~_~,,-'~Ljt:=_ - ~"'J..L .__ ~,:,. It... -...... 'f. <- ........... .L __ ~ ...... ..L-::.,_. :or the commercial sector the ANUFLOOD analysis ~~dicates chat 28 properties had water in the grounds of t~e ;:,;:-operty, plus a further 5 'Wit.h flood level matching gri=~nd ~evel. Of this nUfi1..ber, water is estimated to have atta.~:1ec!. ~verfl~or levels in 12 cases with a further 9 having a match hetween floor height and flood 1evel_ Note that for :-;omme=::ial damage the interview- data was used to defi.:1e -:h.~se chat suffered damage but the similarity in the n~IT'.be!:' -"" properties affected is good. Figure 2.4 and 2.5 present information on the numbers c)[ residential and commercial properties that ,."ould e:-:perience overground or overfloor flooding in height ~ncrements of O.25m. These illustrations can also be used -::0 obtain information on the estimates of the numbers of ;roperties that were flooded to differing depths_ For example Figure 2.4, for residential overfloor flooding, indicates that 66 properties had between zero and O.25m or 1.'3.ter over floor level, the r~G:n.ber with greater than 1 ~etre :verfl~or was 28. :lgures 2.4 and 2_5 also illustrate a most import2:1t ~eature of the Alice Springs flood, namely that small ~~crements in height result in the inundation of very :~creased numbers of properties. For example, Figure 2.4 shows that an increment of flood height of just O.25m would ~esult in a further 110 residential properties experiencing :verfloor flooding. This sensit~vity is unusual and creates ;:oroblems in providing precise estimates of numbers of proper~ies affected by flooding. The degree of accuracy