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history:h_aust_vic_floods

major flooding events in Victoria

Introduction

  • flooding may be:
    • riverine
      • increased river flows from distant rain events
        • peak floodwaters along the Murray River tend to move towards South Australia at a rate of about 10km per day although many factors affect this
          • flooding of the upper Murray results in floodwaters also going north from Barmah Forest northeast of Echuca into the Edward and Wakool rivers which act as anabranches of the Murray River and rejoin it near Swan Hill after 500km of river - the peaks in these rivers must also be taken into account as these tend to take an extra 14 days for the water to rejoin the Murray compared to the flow down the Murray
          • flooding of the Goulburn without flooding of the Upper Murray (as in 1916) is likely to result in reversal of flows with the Goulburn waters also going UP the Murray and into the Edward River
          • Murray Bridge peak tends to occur ~18 days after the peak at Renmark
      • lack of water flow delay mechanisms
    • flash floods from local downpours
      • stormwater trapped by creek levees
      • lack of permeable surface area
      • lack of water flow delay mechanisms
      • inadequate water pumping capacity
      • inadequate drainage
    • tidal
  • some river heights are measured by mAHD which is the elevation in metres with respect to the Australian Height Datum - the height of a point above mean sea level
    • eg. Campaspe at Rochester - 115.6m will flood some 90% of houses as in Oct 2022, 114.6m causes some flooding of buildings as in Jan 2024
  • most other rivers are local heights
    • Goulburn River in Seymour will flood about 12 homes and 20 in the nearby areas at 6.8m peak as in Jan 2024

Melbourne flood events

  • flash flooding from sudden heavy rain storms is relatively common and tend to impact:
    • lower lying roads such as the Dynon Rd bridge
    • Elizabeth St in the CBD which runs along the site of a creek
  • more sustained rain events tend to cause the waterways to break their banks and cause local inundation
    • Maribyrnong River, Anglers Tavern Hotel, Flemington Racecourse
    • Moonee Ponds Creek - Kensington and Nth Melbourne south of Macauley Rd due to local runoff from the hills
      • the area between Nth Melb train station and Macauley train station was once a swamp which was drained in the 19thC but still runs a risk of inundation including residential areas near the current Moonee Ponds Creek
      • significant flood events have occurred 1871, 1891, 1906, 1916, 1924, 1954, 1974 and 1993
      • a 2.8m flood event (1% pa probability) will cause flooding of Hardiman St, Kensington up to Albermarie St
    • Yarra River - this tends to be well mitigated now with the water catchment dams
      • in the past, Collingwood, Richmond, Sth Yarra, Port Melbourne were at risk
  • 1839 Yarra River floods for the 1st time on record
  • 1860 Yarra River floods
  • 1863 Yarra River floods the highest on record to that date
  • 1891 Great Flood affected Richmond, Collingwood and Prahran after 48hrs rain
  • 1906 Maribyrnong River reached record 5.18m flooding Footscray and Kensington
  • 1916 Kensington, Nth Melb
  • 1923 Yarra River flooding impacts Hawthorn, Abbotsford, Belgrave and Fern Tree Gully
  • 1924
  • 1934 48hrs rain dropped 150mm on Melbourne at 330mm in Gippsland, flooding the Yarra River forming a single lake from Warrandyte to South Yarra leaving 6,000 homeless and killing 18 people.
  • 1972 75mm burst of rain floods Elizabeth St, CBD
  • 1974 May 110mm rain in 48hrs causes 2nd largest flood in Kensington with Maribyrnong River reaching 4.2m and affecting mainly Flemington Racecourse which remained out of action until Oct and initiated real time flood monitoring in the catchment
  • 1993 Sept Maribyrnong River reaching 3.83m affecting Kensington
  • 2005 Feb
  • 2010 Nov Flash flooding in the CBD caused significant property damage; Kensington, Nth Melb
  • 2011 Jan flash flooding in Kensington, Nth Melb with water over roads trapping cars in Stubbs Street and Macauley Road. Drains and infrastructure improvements were then implemented and have reduced the risk of a similar flood having the same impact. Maribyrnong River reaching 2.21m;

Regional Victorian events

  • 1870 northern Victoria and the Murray impacted by record floods which have not been matched along the length of the Murray since
    • caused much loss of life from drowning in the Murray-Darling Basin in particular from an east coast low (ECL) in April 1870 and two Victorian weather systems in September and October 1870 1)
  • 1890 Murray flooded
  • 1909 central and western Victoria, Halls gap and Stawell were evacuated
  • Sept 1916 Seymour and Shepparton flooded - largest in history
  • 1917 Seymour flooded - largest in history; Murray flooded
  • 1931 Murray flooded
  • 1934 350mm rain fell in south Gippsland over 48hrs; Seymour flooded;
  • 1946 Glenelg River floods rising 300mm per hour after 220mm rain over 4 days in the Casterton region
  • 1952 Seymour flooded
  • 1955 Murray flooded
  • 1956 Murray flood - highest on record in Sth Aust; record volumes of inflow to Hume Reservoir in April, May and July; April 3-4x monthly average rain fell in most of NE Vic, esp. upper Ovens;
  • 1973 Seymour flooded
  • May 1974 Goulburn peaked at 7.64m in Seymour - the highest since the Eildon weir was built and 5th largest in history, caused by storm runoff from the catchment downstream of Eildon
  • 1975 Seymour flooded at 7.12 m (137.364 metres AHD)
  • 1993 NorthEast Victoria caused major damage to rural and residential properties, particularly along the Broken and Ovens River systems
  • Sept-Oct 1993 Seymour flooding 6.66 metres (136.904 metres AHD)
  • 2010 widespread heavy rains over 5 days affects most of Victoria; Jingellic Gauge on the Upper Murray hits 7.64m;
  • 2011 western and central Victoria affected by flooding more severe than in 2010
  • 2012 Murray River flood in Walwa which reached 7.91 metres on the Jingellic Gauge is the highest flood since records began in 1890.
  • 2016 western Victoria and the Otways suffer heavy rains resulting in prolonged closure of the Great Ocean Rd due to landslides and rockfalls
  • Oct 2022 overnight major flooding of the Loddon from release of weir waters catches rooftop camper by surprise at Newbridge Recreation Reserve camp ground requiring helicopter - Recreation reserve suffers major flood damage
  • Oct 2022 major flooding of the Campaspe floods 90% of houses in Rochester and flooding of Goulburn affects parts of Seymour
  • Jan 2024 major flooding of the Campaspe floods impacts some houses in Rochester (1m lower than Oct 2022 floods) and flooding of Goulburn affects parts of Seymour while Yea is also impacted requiring evacuations
history/h_aust_vic_floods.txt · Last modified: 2024/01/10 00:00 by gary1

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