Floodplain Managers

FLOODPLAIN

VOL 2 No. 2

MANAGER APRIL 2006

CONNECTING AND INFORMING AUSTRALIAN FLOODPLAIN MANAGERS

INSIDE HOW MANY HOMES CAN Editorial 2 FLOOD? Interview with Mike Edwards 2 New research commissioned by The Insurance Council of Diary 3 Australia and undertaken by Macquarie University's Risk Landuse Planning Course 3 Frontiers Centre suggests that more than 170,000 Australian BOM Workshops 3 residential properties are affected by riverine flooding and Flood Estimation Workshop 3 hundreds of thousands may be at risk from coastal inundation. NSW Flood Conference 3 Risk Study Continued 4 Riverine Flooding Flood Risk Workshop 4 The research on riverine flooding was presented at the 46th Flooded Road Risks 5 Annual FMA Conference (see page 3) by Roy Leigh, Risk Lessons from New Orleans 5 Scientist at the Risk Frontiers Centre and draws on flood studies from more than 300 locations. It takes from research National Flood Database 5 by Geoscience Australia into the availability of flood studies Council Guilty of Nuisance 5 (see page 5) and also work by the NSW SES into the number Window on Weather 5 of flood affected properties in NSW and provides additional New Vic Storm Warnings 6 research and analysis. New HQ for BOM 6 BOM Wins Website Honours 6 Estimates are based on the number of properties affected, up to Final NSW LEP Template 6 the 1 in 100 flood level, as reported in the flood studies. This of course ignores the thousands of additional properties which Revenge of the River Gods 6 would be affected by floods up to the Probable Maximum th QLD SES 30 Book 6 Flood or the thousands more not affected by main channel Seasonal Outlook 6 flooding but by overland flows. Australian Floods 7 Mr Leigh informed conference delegates that overground International News 8 flooding was chosen as the measure for two reasons: SUBSCRIBE It is reported in most flood studies and, from an insurance point of view, this would be the trigger for many claims. Floodplain Manager is distributed to subscribers. Six editions are He acknowledged that information about overfloor flooding published each year. The annual risks, and even depths and velocities, would be more helpful subscription fee is $99 including but this type of data is simply not widely available. Likewise GST. Back issues are available. there is limited data about less frequent floods.

Subscription, inquiries should be The results of the research are summarised in Table 1. directed to Molino Stewart continued page 4 P: 02 9891 5399 E: [email protected] W: www.molinostewart.com.au ISSN 1832-4541

Copyright © Molino Stewart Pty Ltd 2005. No part of this publication may be reproduced or transmitted in any form without the permission of the publisher. Permission inquiries should be emailed to [email protected] FLOODPLAIN MANAGER page 2 April 2006

EDITORIAL A WORD FROM MIKE EDWARDS It was great meeting so many of you at the FMA Conference last As reported in December 2005, Mike Edwards took on the role month and I thank each of you for of Manager of the Victorian Department of Sustainability and your kind words about this Environment's Floodplain Management Unit. Floodplain publication. In coming issues we Manager caught up with Mike to hear what he sees as the will explore themes from the challenges and opportunities in this new role. conference. “A Decision was made some years ago to devolve Our lead article draws from responsibility for floodplain management to the CMA’s in research presented at the Victoria which was an appropriate decision”, Mike said. “But conference which goes some way in recent years it has become clear that there still needs to be to quantifying how vulnerable to significant support at a state level. Not only to provide state flooding we are. Flooding up to policy direction but also to provide support for projects funded the PMF could possibly double under the NDMP. “One of my goals is to raise the profile of the numbers quoted and if that is floodplain management within the DSE and thereby be better multiplied by occupancy ratios placed to help the CMA’s and local government.” you soon approach one million Australians susceptible to riverine Several projects had already started before Mike’s arrival, flooding alone. including an update of the Victorian Flood Database which should be finalised later this year. Mike and his team are also Each will be a life disrupted, working on a new Manual of Floodplain Management and possibly changed for ever. It will Policy and have set themselves the goal of completing it by the be little consolation to the cyclone end of the financial year. devastated people of Innisfail to know that there is still a long way Mike also said, “The existing Victorian Flood Strategy was to go in rehousing people affected developed in 1998 and a lot of things have happened since then by the Asian Tsunami and so we are also aiming to have a process for updating the Hurricane Katrina let alone Strategy established by December.” restoring communities and economies, more than 12 months Floodplain Manager suggested a significant challenge in after those events. updating the strategy will be determining who should take responsibility for the ongoing maintenance of Victoria’s many I was reminded just how long levees. Mike responded: “We need to determine who is best flood impacts linger when a placed to manage the levees but we also need to find an colleague finalised a voluntary acceptable way to manage the liabilities that come with them.” purchase with NDMP funds the other day. The owner could now Mike has been encouraged by the Victorian Civil and afford to live elsewhere and Administrative Tribunal’s support of floodplain management. hoped she would no longer suffer “I am an advocate for prevention of inappropriate development the anxiety attacks she has had in on floodplains: using maps and planning controls to aid good heavy rain ever since a flood decision making. trapped her and her children in the house 17 years ago. “Recent Tribunal decisions have shown that those administrations with well thought out flood policies and plans If good planning can reduce these get good outcomes from the Tribunal. We want to provide human impacts then it is worth it. them with support in making those policies and plans.”

Steven Molino

DIARY RISK BASED LANDUSE PLANNING COURSE AUSTRALIAN CONFERENCES • Risk Based Land Use Planning Course EMA is conducting three courses in 2006 on the See article on this page practical integration of risk management framework into land use planning. The first EMA program Mt Macedon, Victoria th May 29-June 1, 2006 course will commence 29 May. This course http://www.ema.gov.au/ now attracts Planning Institute of Australia Continuing Professional Development points and • Flood Estimation for Floodplain Managers will soon be accredited nationally. See article this page More info: www.ema.gov.au Clayton Campus, Monash University Jul 3-5, 2006 BOM WORKSHOPS FOR WESTERN [email protected] SYDNEY • 30th Hydrology and Water Resources The BOM will conduct two free Radar User Symposium Past, Present and Future Workshops at the University of Western Launceston, Tasmania Dec 4-7, 2006 Sydney's Hawkesbury Campus on Saturday 8th [email protected] April 2006. Bookings are essential, and can be www.cdesign.com.au/hydrology2006 made by contacting 02 9296 1555 or via email to

[email protected] INTERNATIONAL CONFERENCES • 2nd International Symposium on FLOOD ESTIMATION WORKSHOP Quantitative Precipitation Forecasting In response to the need for additional training and Hydrology expressed by Catchment Management Boulder, Colorado USA June 4-8, 2006 Authorities and Melbourne Water, Monash http://www.mmm.ucar.edu/events/qpf06 University is planning a workshop on “Flood

Estimation for Floodplain Managers”. At this • Association of State Floodplain Managers th stage registrations are only invited from CMA, 30 Annual Conference 2006 DSE and MW employees and should be Albuquerque, NM USA June 11-16, 2006 submitted by 1 May 2006. www.floods.org/Conferences,%20Calendar/albu querque.asp NSW FLOOD CONFERENCE 2006

nd • 2 International Symposium “Preventing The 46th Annual Floodplain Management and Fighting Hydrological Disasters” Authorities Conference, held at Lismore on the Timisoara, Romania Jun 29-July 1, 2006 NSW North Coast from the 28th February to 2nd [email protected] March was one of the most successful ever with over 300 delegates attending. Many came from • Frontiers in Flood Research interstate including floodplain managers and IAHS-UNESCO VIIIth Kovacs Colloquium practitioners from Qld, Vic, SA, NT and the Paris, France Jun 30 -July 1, 2006 ACT. International keynotes speakers Larry [email protected] Larson and Adri Verwey gave interesting respective insights into the US response to • Flood and Coastal Management Hurricane Katrina and Dutch efforts to improve Conference flood protection. Full conference papers will University of York, UK July 4-6, 2006 soon be available on the NSW FMA website at www.defra.gov.uk/environ/fcd/conference/confer http://www.floods.org.au ence.htm

(continued from page 1) of the population is located within 7km of the coast. Many of these properties are also at risk of riverine flooding.

The “sea change” phenomenon is exacerbating the situation with experts warning much of the new housing built near beaches will go under water in a big storm.

The risks were exposed when storms verging on The seven most flood-prone areas account for cyclone intensity lashed southern Queensland just over 40% of the total number of identified and northern NSW from Fraser Island to near properties flood-prone to the ARI 100-year level. Coffs Harbour, with major damage recorded to The worst 60 areas (20% of the locations in the the main beach at Noosa. study) contain 80% of the flood-prone properties. About 22% of the identified flood- ICA spokesman Rod Frail commends the study prone properties are located in Brisbane City, saying there is not enough information on coastal Ipswich and the Gold Coast. inundation to give insurers an understanding of the risks and damage associated with these Table 2 shows the statistics for the seven most disasters. flood affected areas: "We need to fill in the blanks for yet another peril faced by home owners on the coast and we ` want to find a solution that will provide universal cover," he said. More info: www.unisdr.org/ppew www.riskfrontiers.com/floodAUS/floodausbroch ure.htm

Coastal Inundation www.theaustralian.news.com.au/story/0,20867,1 8360927-2702,00.html Dr Keping Chen, also of the Risk Frontiers Centre, used high-resolution geospatial data such www.theaustralian.news.com.au/common/story_ as exposures, shorelines and elevation, to page/0,5744,18421644%255E30417,00.html produce a national study of overall coastal inundation hazards including tsunamis, tropical FLOOD RISK WORKSHOP cyclones, coastal flooding, and sea level rise. SUCCESS

He found 75 per cent of addresses, including Over 100 people attended the inaugural flood residential, commercial and industrial sites were risk workshop which was run immediately vulnerable in 37 local government areas, based preceding the NSW FMA conference. Designed on two threshold parameters: being within 3km to give a broad overview of flood risks and the of the coast and less than 6 metres above sea procedures for floodplain management in NSW, level. it proved extremely popular with elected councillors and professional staff alike. It is The Gold Coast leads the list with more than intended the workshop be run prior to next year’s 92,000 addresses under threat followed by conference. The FMA is working with DNR and Brisbane (32,909), Rockingham in Western UTS to develop a more in depth course for Australia (27,509), Gosford in NSW (22,796) engineers and planners. An outline of the new and Kingston in Victoria (19,508). Most of the draft course content can be viewed at addresses are located on the east coast in NSW www.floods.org.au/Html/education.html and Queensland The study also found that 50%

THE ROAD LESS TRAVELLED NATIONAL FLOOD DATABASE THE BETTER NOW ONLINE

In a recent survey conducted by the NSW SES a The National Database of Riverine Flood Hazard disturbing 34.9% of respondents said they would and Risk Studies is now available for searching drive through floodwaters. With deliberate comprehensive information on over a thousand entering of floodwaters the biggest killer in a flood studies nationally. The database was flood, this is a worrying statistic. The survey, development by Geosciences Australia through undertaken in the four flood affected funding provided by the Department of communities of Albury, Narrabri, Maitland and Transport and Regional Services and it is hoped Grafton in late in 2005, showed 22.2% of the database will be spatially enabled by the end respondents, if faced with floodwater over a of the year. road, would continue driving. A further 12.7% said they would assess the situation before www.ga.gov.au/oracle/flood proceeding, some stating they would depth test by walking into the floodwaters. COUNCIL GUILTY OF NUISANCE

The results are alarming as deliberate entry into The NSW Court of Appeal found Port Stephens floodwaters - whether on foot, bike, or by Council guilty of nuisance on the Nelson Bay vehicle - is the single biggest killer in a flood property, Melaleuca Estate, as a result of event. It is worth noting that four wheel drives drainage works it carried out in 1993. do not significantly increase safety. As little as 40 to 60cm of water is sufficient for a vehicle to The court found the council had broken float and for the current to sweep it off the road. undertakings to install a pumping station and pollution traps when it opened a pipeline, For pedestrians, as little as 15cm of fast flowing causing stormwater and pollutants to enter the floodwater is all it takes to knock a person off land, reducing its development potential. The their feet. council must stop discharging stormwater onto Melaleuca’s land, a practice the council has more info: www.ses.nsw.gov.au/news/3328.html undertaken well before the developer purchased it. Council intends appealing to the High Court. NO N.O. IN AUSTRALIA For a transcript of ruling, visit The October 2005 issue of Floodplain Manager www.lawlink.nsw.gov.au/scjudgments/2006nswc considered the lessons to be learned from the US a.nsf/09da2a0a2a27441dca2570e6001e144d/d4 emergency response to Hurricane Katrina. 425bb8420e41b7ca25712200029e89?OpenDocu In the February 2006 edition of the Australian ment. Journal of Emergency Management, John Handmer from RMIT provides a detailed critique WINDOW ON WEATHER of this event and concludes a similar situation is unlikely to occur in Australia. He notes however A new 'weather window' television studio at the that we are placing increasing numbers of elderly BOM’s NSW Regional Office in Sydney has (vulnerable) people in coastal developments at been opened at a cost of $60,000, ahead of risk of storm surge and plans for evacuating tens World Meteorological Day celebrations. of thousands from our most populous floodplains have yet to be tested. A fixed camera, lights, audio equipment and a digital fibre optic link will allow for live crosses More info: [email protected] direct to forecasters at short notice to warn communities under threat from severe weather conditions. During severe weather the studio will be open from early morning until late evening.

NEW STORM WARNING SYSTEM NSW LEP TEMPLATE FINALISED FOR VICTORIA The NSW Government has released the final A new graphical system of severe thunderstorm version of its standard LEP template (Floodplain warnings will be available from 15 March 2006 Manager Feb 2006). This will see council on the BOM website. The system was developed adopting a single LEP for their entire by the Melbourne BOM Research Centre in municipality based on the standard LEP. conjunction with Bureau forecasters in Sydney, and the NSW SES, and further refined for the It contains a mandatory set of legal provisions, Victorian service. Text-based warnings are planning definitions and zones that available over the phone for the cost of a local municipalities are required to phase in over the call on 1300 659 217. next five years. This includes standard flood provisions. www.bom.gov.au/weather/vic The standard LEP and supporting documnation NEW HQ MARKS BOM can be found at: CENTENARY http://www.planning.nsw.gov.au/planning_refor ms/index.asp#high New offices for the BOM have been officially opened at Melbourne’s Docklands as part of REVENGE IS SWEET World Meteorological Day celebrations. Revenge of the River Gods is a fascinating Marking the 100th anniversary year of the documentary on China’s worst flood in living Bureau, the high tech offices boast National history. During the summer of 1998 vast areas of Meteorological Library, a Training Centre and the country were inundated and the Peoples several scientific laboratories as well as around Liberation Army was mobilised into the biggest $60M worth of computing facilities including a force since liberation in 1949 to literally hold $22M ‘super computer’ back the waters with human walls.

"The Australian Government's investment in the To order go to: Bureau's science and technology infrastructure www.abc.net.au/programsales/s1123363.htm indicates the Government's recognition of the TH Bureau's significant role in providing QLD SES 30 BOOK meteorological services to the Australian community, and advice to the Government on The Qld SES has issued a book chronically its weather and climate-related issues", said Mr first 30 years since its inception in 1975. more Greg Hunt MP info: www.emergency.qld.gov.au/ses/publications/ BOM WINS WEBSITE HONOURS SEASONAL OUTLOOK The Bureau of Meteorology was awarded the most popular government website and nationally The current seasonal rainfall odds do not the most popular Australian education reference strongly favour either wetter or drier than website of 2005 at the Second Hitwise average conditions. Therefore, the chances of Australian Online Performers awards. accumulating at least median rain during the June quarter (Apr-June) are close to 50% across "This is the second year in a row the Bureau has the entire country achieved recognition at these awards," said Mr Greg Hunt MP. www.bom.gov.au/announcements/media_release s/climate/ahead/20051219R.shtml

"It is a very rare event to receive two cyclones AUSTRALIAN FLOODS within as many months and testimony to this is the fact Karratha is experiencing its wettest year The following flood reports are provided on record," said Mr Vincent. courtesy of the Bureau of Meteorology. The picnic areas surrounding Harding Dam, WA FLOODING however are still closed to the public due to continued flooding. Murchison River Catchment: Heavy rainfall resulted in the highest recorded flood along the www.watercorporation.com.au/media/media_det entire length of the Murchison River. More than ail.cfm?id=517 20 pastoral properties reported significant damage and heavy infrastructure losses QLD FLOODING combined with significant scouring of the Murchison floodplain. Tropical Cyclone Larry crossed the North Tropical Coast near Innisfail in the early hours of For the first time in Australia, MODIS satellite 20th March, resulting in heavy rainfall between imagery was used to accurately forecast travel Ingham to just south of Cairns. Due to the speed time and the extent of inundation along the of the cyclone movement the coastal rain was not Murchison River. It provided information on as intense as expected and only a few river peak flow timing at the coastal town of Kalbarri basins had any significant flooding. However a and possible peak height to give FESA day later, very heavy rainfall fell in the confidence that temporary levee banks would Leichhardt River catchment resulting in record keep the town and essential services safe. flood levels in the river. A total of 36 specific flood warnings were issued for the event. Gascoyne River Catchment: First peak at Nine Mile Bridge at Carnarvon was 4.5m and the During the first few weeks of March isolated second was 5.1m. instances of flooding also occurred in the Thomson River, Tully River, Georgina River, WEST PILBARA WATER SUPPLY Nicholson River and Norman River due to heavy SWITCHED rainfall.

The Water Corporation switched the West At the end of the month further heavy rain Pilbara water supply scheme to the Millstream occurred along the North Tropical Coast with aquifer from March 2nd to April 11th as a result renewed rises occurring in the Tully River. Four of extreme flooding experienced in the region warnings were issued for this event. and at the Harding River Dam. Tully and Murray Rivers: Received the North West Regional Business Manager, Ashley heaviest rainfall from Larry with over 500mm Vincent, said by switching the scheme to the recorded at Euramo to 22nd March. The Tully Millstream aquifer a consistent supply can be River at Euramo eventually overtopped the ensured until the Harding Dam settles and Bruce Highway 21st March. Levels at Euramo necessary maintenance work to a downstream peaked at 8.60m during 22nd March. The Murray pump station is completed. River at Murray Flats overtopped the Bruce Highway on 21st March and peaked at 8.1m Following 300 millimetres of rainfall from during 22nd March. High levels were maintained Cyclone Emma, the already full Harding Dam for several days before levels fell below the reached the second highest level since its Bruce Highway for both rivers on the 24th commissioning in 1985. March.

Mulgrave River: Rapid rises occurred on 20th

March. The highest recorded rainfall was INTERNATIONAL NEWS 139mm in 3hours to 9am at the Boulders on Babinda Creek. Mulgrave River had major WORLDWIDE FLOODING flooding in the Gordonvale to Peets Bridge area, the level peaking at 15.2m. Iraq: Erbil, Sallahaddin, Kirkuk, Dyiala and Missan. Heavy rains and subsidiary snow melts Leichhardt River: Very heavy rain occurred in saw the evacuation of 28,000 as the Tigris River the 24 hours to 9am 22nd March with the highest flooded for a week from February 5th. Erbil total of 435mm recorded at Gereta Station. After experienced 103 mm of rain only 8 hours of intense rainfall Gunpowder Creek reached a 10.63m peak (the highest peak, Brazil: Thirty-six days of rain between February since records commenced in 1971) on the 23rd. 13th and March 20th resulted in the Acre River At Lorraine, the river rose rapidly on the 23rd and reaching 16.65 meters above the normal level, reached a peak of 16.9m, the highest level 7,791 buildings inundated and 33,000 people recorded since records commenced in 1974. This displaced with 8,000 left homeless in Rio Branco level was maintained overnight before falling city. quickly on Saturday. At Floraville, the river Indonesia: North Sulawesi Province including peaked at 9.91m on the 26th – the highest level Manado. Heavy monsoonal rains have caused since records commenced in 1984. Locals advise flooding and landslides with floodwaters up to 4 that this flood was the highest in the area since metres. A low pressure system contributed to 1964. heavy downpours resulting in 33 deaths, and over US$27.5M in damages to 2,067 houses, NT FLOODING 1,115 hectares of agricultural area, and 11 hectares of plantation area, plus the loss of 9,773 Early in February, the remnants of a tropical low head of livestock. passed into the Victoria River District and dissipated in the Tanami Desert causing South Africa: Northwest Province, Taung widespread flooding. municipality. More than 1,000 families from eight heavily flooded villages are left homeless Victoria River at Victoria River Crossing: after heavy rain over five days. $780M Rand is Peaked at 21.13m (9.23m over the bridge deck) nd needed to fix damaged infrastructure as roads on the 2 February. and bridges are washed away. Victoria River At Coolibah: Peaked at a major rd USA: Hawaii, Northern Kauai. Seven died as the flood level of 16.94m at 10pm on 3 February. Kaloko dam burst after 10 days of heavy rain. Katherine River at Katherine: In early April 1.2 billion litres of water spilled into the valley the Katherine River flooded reaching a peak causing floods and mudslides causing US$12 close to 19m at the Katherine River Bridge and million in damage to beaches and reefs several flooding the township of Katherine. It swamped miles from the dam. about 50 homes and caused "significant damage" Central Europe: Czech Republic, Austria, to about a dozen. Germany. Heavy rain and snow melts throughout Flooding was continuing as Floodplain Manager central Europe have affected 45 cities and towns went to press. More details will be provided in leaving over 20 rivers at dangerous flood levels. the June edition. Dams and levies have been breached leaving 48,000 hectares of farmland flooded total. A total of 16 people have been reported dead as a result of the flooding and US$217M in damages.