Hydrology of Recent Flooding in South East Queensland

Transcription

1 Hydrology of Recent Flooding in South East Queensland G. Hausler

2 TOPICS Prelude eu e Rainfalls Catchments Flooding Aftermath

3 Prelude Sea Surface Temperature anomalies for December 2010 Most likely return to neutral conditions from now

4 SOI

5 December Weather Patterns 10 December December December December 2010

6 December 2010 Rainfall (Deciles) Highest on Record

7 December 2010 Rainfalls S.E.Qld Daily Rainfalls - December 2010 Bundaberg Brisbane Chinchilla Ra infall (mm) Wed 01 Dec Fri 03 Dec Mon 27 Dec Wed 29 Dec Fri 31 Dec Sun 05 Dec Tue 07 Dec Thu 09 Dec Sat 11 Dec Mon 13 Dec Wed 15 Dec Fri 17 Dec Sun 19 Dec Tue 21 Dec Thu 23 Dec Sat 25 Dec Day Date Time

8 January Weather Patterns 6 January January January January 2011

9 January 2011 Rainfall (Deciles)

10 January 2011 Rainfalls S.E.Qld Daily Rainfalls - January 2010 Bundaberg Brisbane Chinchilla Rainfall (mm) Fri 31 Dec Sun 02 Jan Tue 04 Jan Thu 06 Jan Sat 08 Jan Mon 10 Jan Wed 12 Jan Fri 14 Jan Sun 16 Jan Tue 18 Jan Thu 20 Jan Sat 22 Jan Mon 24 Jan Wed 26 Jan Fri 28 Jan Sun 30 Jan Day Date Time

11 Flood Events SE Qld (Not complete) Condamine at Warwick 27 th Dec 2010 & 11 th Jan 201 Myall Ck at Dalby 27 th Dec 2010 & 10 th Jan 2011 Charleys Ck at Chinchilla 28 th Dec 2010 & 12 th Jan 2011 Burnett at Gayndah/Bundaberg 29 th 30 th Dec 2010 Condamine R at Condamine 1 st Jan 2011 & 14 th 17 th Jan Bl Balonne at St George 9 th Jan & 23 rd Jan 2011 East Ck/Gowrie Ck at Toowoomba 10 th Jan 2011 Lockyer Ck at Helidon and Grantham 10 th Jan 2011 Murphys Ck at Postmans Ridge 10 th Jan 2011 Oakey Ck at Oakey 11 th Jan 2011 Caboolture R at Caboolture 11 th Jan 2011 Mary R at Gympie & Maryborough 11 th Jan 2011 Laidley Ck at Laidley 11 th Jan 2011 Bremer R at Ipswich 12 th Jan 2011 Brisbane R at Fernvale & Brisbane 13 th Jan 2011 McIntyre at Goondiwindi 14 th Jan 2011

12 Condamine Catchment - Flooding Gowrie Creek Toowoomba Where East and West Creeks meet

13 Condamine River at Warwick Condamine R at Warwick Catchment area of 1,360 sq. km. Two flood events» Monday 27 th December 2010» Tuesday 11 th January 2011 Up to 50 homes affected Highest flood at Warwick since Possibly 4 th largest flood in about 130 years

14 Flood Hydrographs Condamine at Warwick December 2010 January 2011

15 Myall Ck at Dalby Catchment Area

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17 Myall Ck at Dalby Tributary of Condamine River Catchment Area around 1560 sq km Flows through Dalby township Two flood events 2 nd event largest» 27 th Dec about 3.5 metres on gauge» 10 th Jan about 3.75 metres on gauge About 50 to 100 homes affected (from newspaper reports)

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19 January 2011 event 3 rd largest in 70 years of record

20 Charleys Ck at Chinchilla Catchment Area

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22 Flood Events at Chinchilla hill Charleys Ck at Chinchilla catchment area 3,460 sq km. Tributary of Condamine River. Two flood events:» Tuesday 28 th December» Wednesday 12 th January Many houses evacuated. The December and January flood events exceeded the 1983 flood (6.75 metres peak gauge height) but did not exceed the record flood event of 1942 (7.95 metres peak gauge height).

23 Flood Hydrographs Charleys Creek December 2010 January 2011

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25 Lockyer Ck Flooding Lockyer Ck downstream Gatton-Helidon Road Bridge

26 Lockyer Creek Catchment Area Boundary Grantham

27 Sandy Ck AL 3-hourly rainfall 9 9th to 11 12th January December Rainfall (mm) Sun 09 9:00 Sun 09 12:00 Sun 09 15:00 Sun 09 18:00 Sun 09 21:00 Mon 10 0:00 Mon 10 3:00 Mon 10 6:00 Mon 10 9:00 Mon 10 12:00 Mon 10 15:00 Mon 10 18:00 Mon 10 21:00 Tue 11 0:00 Tue 11 3:00 Tue 11 6:00 Tue 11 9:00 Tue 11 12:00 Tue 11 15:00 Tue 11 18:00 Tue 11 21:00 Wed 12 0:00 Wed 12 3:00 Wed 12 6:00 Wed 12 9:00 3 hr period ending day-date-time

28 River Heights - Lockyer Ck at Helidon Approx 8.5 m rise in an hour Flagstone Creek

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30 A Sandy Creek B Railway Breakout Flow Direction Lockyer Creek C

31 Annual Maximum Gauge Heights for Lockyer Ck at Helidon Approximate only. Helidon 2 adjusted Helidon Gauge Height (m) 1966/ / / / / / / / / / / / / / / / / /1 2002/3 2004/5 2006/7 2008/9 2010/11 Year

32 Bib Brisbane River Catchment Brisbane River at Mt Crosby Pump Station

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34 Bib Brisbane River Catchment Total catchment area 14,000 sq. km 50% catchment area upstream of Wivenhoe Dam Major tributaries upstream of Wivenhoe Dam» Stanley River» Cooyar Ck» Emu Ck» Cressbrook Ck» Kilcoy Ck Major Tributaries downstream of Wivenhoe e Dam» Lockyer Ck» Warrill Ck» Bremer River» Oxley Ck

35 Brisbane River Catchment Rainfalls January December hours to 9am -December 2010 Station Name Brisbane River catchment upstream Wivenhoe Dam Peachester Woodford Kilcoy AL * Somerset Dam Hw AL-B * Top Of Brisbane AL * Blackbutt Yarraman AL * Cooyar Creek TM * Crows Nest Esk Wivenhoe Dam Hw AL-B * Wivenhoe Dam Tw AL-B * Bi Brisbane River catchment tdownstream of fwivenhoe Dam Toowoomba AL * Tenthill TM * Gatton AL * Lowood Marburg AL * Kalbar Weir AL * Amberley AL-P * Jindalee AL * Brisbane City AL *

36 Wivenhoe Dam 300+ mm in 12 hours on Tuesday 11 th December 140 Wivenhoe 3-hourly rainfall 9th to 12th December January Rainfall (mm) Sun 09 9:00 Sun 09 12:00 Sun 09 15:00 Sun 09 18:00 Sun 09 21:00 Mon 10 0:00 Mon 10 3:00 Mon 10 6:00 Mon 10 9:00 Mon 10 12:00 Mon 10 15:00 Mon 10 18:00 Mon 10 21:00 Tue 11 0:00 Tue 11 3:00 Tue 11 6:00 Tue 11 9:00 Tue 11 12:00 Tue 11 15:00 Tue 11 18:00 Tue 11 21:00 Wed 12 0:00 Wed 12 3:00 Wed 12 6:00 Wed 12 9:00 3 hr period ending day-date-time

37 Brisbane River at Gregor Creek Brisbane River at Wivenhoe Dam Brisbane River at City HeadwaterGauge

38 Brisbane Flooding January 2011 Flood peaked at 4.45 m on City Gauge Major flood event rainfalls in parts of catchment exceeded 100 yr ARI magnitudes - but 1 metre less than 1974 flood 3 to 4 metres lower than 1893 and 1841 floods Jan 2011 Peak

39 General Observations Flooding SE Qld Major flooding in many catchments In many catchments the Dec and January 2011 flood events were only the 3 rd to 5 th largest on record. Exceptions were: Condamine largest flood on record Lockyer Ck at Helidon and Grantham much larger than any previously recorded.

40 SE Qld Dec. and Jan. floods in context Recent flood possibly most significant in terms of property and infrastructure damage ---- but Most catastrophic flood event in Australia was Gundagai flood of 1852.» Town washed away, rebuilt elsewhere» 70 to 90 people (1/3 towns population killed) 1916 Clermont flood in Qld» 65 people killed» Town rebuilt in different location Black February 1893 flood in Brisbane» Two cyclones crossed coast» Victoria and Indooroopilly bridges washed away,» 11 people killed; 190 hospitalised Our variable climate and development on floodplains guarantees that these events will be repeated, climate change or no climate change.

41 AFTERMATH Significant volumes of bank and bed material has been shifted from streams in South East Queensland In particular..

42 Brisbane River Downstream of Wivenhoe Dam

43 Lockyer Ck at Helidon

44 Laidley Ck downstream of Laidley - Forest Hill Road Bridge

45 Tenthill Ck upstream of Gatton-Helidon Road Bridge

46 Flagstone Creek downstream Duncan s Bridge

47 Murphys Creek before Murphys Creek after

48 Gully Erosion Darling Downs

49 Fin