Related - Floodplain Manager February 2020

Floods Extinguish the Fires: NSW

The Bureau of Meteorology (BoM) reported 391.6 mm of rain for Sydney between 7 and 10 February, which set the record for the highest average rainfall for February and the city’s wettest period since 1990.

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The NSW State Emergency Service (NSW SES) received 1,393 calls for help and undertook 15 flood rescues as flash floods caused damage to homes and left thousands without power across NSW. Authorities issued evacuation orders on 9 February for towns along the Hawkesbury River including Pitt Town Bottoms and Richmond Lowlands.  Evacuation orders were also issued for Moorebank, Chipping Norton and Milperra along the Georges River on 11 February. The rainfall was good news for dam inflow as Warragamba Dam received almost 100 mm in the 32 hours to 7 February after months of water restrictions. Meanwhile, the rail network was severely affected by rains which triggered a landslide at Leura in the Blue Mountains causing damage that could take months to rectify (Read here, here and here).

Floods Extinguish the Fires: Queensland

Several areas of Queensland’s Sunshine Coast and Gold Coast were exposed to heavy rain and flooding in early February.

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According to the BoM, Marcoola recorded 231.8 mm, Nambour 200.8 mm and Southport 177 mm of rain in a 24-hour period to 13 February. Flood warnings were issued for communities near the Coomera River at Oxenford, where river levels rose to over three metres, well above the major flood level (2.5 metres). One person died after being swept away by floodwaters in Conondale, whilst another woman was reported missing on 12 February in the Tallebudgera Valley and was found alive and well five days later close to where she was last seen. Queensland State Emergency Service undertook 19 swift water rescues and responded to over 300 callouts. Meanwhile in the Sunshine Coast town of Coolum, forty residents of an aged care facility were evacuated as flash flooding threatened to inundate parts of the building. Widespread power outages were experienced across the state with approximately 2,000 customers affected (Read here, here and here).

Port Lincoln Goes Under

The Port Lincoln region in South Australia is facing large damage bills following a deluge on 1 February.

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The weather station at the marina recorded 76.2 mm of rain in just 40 minutes and approximately 27 megalitres of water was pumped from the city’s three pumping stations. Floodwaters carried away cars, damaged over 75 homes, and soiled the cities foreshore. Port Lincoln Council has responded by trucking in clean sand from clean beaches to reduce the risk of contamination from the flood waters (Read here).

BoM Tailors Flood Warnings for Graziers

In the wake of the Queensland floods which killed more than 500,000 cattle, the BoM has responded to feedback collected from the livestock industry in order to tailor flood warnings.

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The Northern Australia Climate Program has analysed feedback from the livestock industry on the warnings the BoM put out during the 2019 floods. The response from graziers was that they wanted more warning that cold weather was coming so they could stock up on fodder and supplements for their cattle. The BoM has taken this on board and has also included river heights related to those experienced during previous floods in order to better inform and relate to local graziers (Read here, here).

Argument over who has access to Floodwaters

Following a meeting between NSW Water Minister Melinda Pavey and the irrigation industry for the Barwon-Darling River, a three week embargo on floodplain harvesting was announced to give the river system the full benefit of the recent rainfall.

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However, the embargo has been shrouded in controversy as it was temporarily lifted for upstream irrigators after more than 250 mm of rain fell over the Gwydir and Namoi valleys causing flash flooding. The temporary lift enabled farmers to harvest and redistribute floodplain waters to reduce damage to farm infrastructure such as gates, pumps, levees or banks. Whereas downstream irrigators expressed frustration at the decision to lift the embargo as Australian Floodplain Association chairman Justin McClure said “…there was no such consultation with downstream users about the benefits of not lifting the embargo”. McClure continued that by “giving some farmers authority to direct floodwaters into their private storages, the government had failed to maximise the first flush of the river” (Read here ).

Flood Amendments to Toowoomba Planning Scheme Adopted

Toowoomba Regional Council’s Planning and Development Committee recommended adopting amendment number 17 to the Toowoomba Region Planning Scheme which relates to region-wide management of flood risk.

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The amendment is the culmination of numerous flood studies and extensive community consultation in the region over the past five years. The proposed amendment ensures that measures such as building design standards are in place to control future development in flood-affected areas, to minimise risk to people and property and prevent worsening flooding. The committee recommended that Council uses provisions in the Planning Act 2016 that exempts Council from potential claims for compensation in relation to the new development controls. The exemption is likely to relate to 2,366 properties in seven high flood risk towns, although these properties are mostly community facilities and public zones thus unlikely to be affected by reduced property values, higher insurance prices and reduced saleability. The Real Estate Institute of Queensland has advised that flood related impacts on property value and sales relate more to flood events rather than the designation of flood risk by Council (Read more here).

Who Bears the Cost of Climate-related Disasters?

As more frequent climate extremes are set to occur in the future, the question arises as to how government and insurers will continue to meet costs and who is ultimately responsible.

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The financial costs associated with disasters includes tangible damages such as buildings, contents and infrastructure but also many intangible costs such as loss of life and health impacts, social impacts and loss of ecosystem services . For example, the Australian Business Roundtable in 2016 found that for the 2011 Queensland Floods (FM 2011) the social impacts outweighed the direct financial impacts by $3.9 billion to $3.1 billion.  While much of the direct financial impacts may be covered by insurance payments and federal government assistance to replace or repair damaged infrastructure, the  Government’s 13-week Disaster Recovery Allowance for loss of employment or other income  and support from not-for-profits falls well short of what is needed to cover the indirect costs. With insurers increasing premiums to cover expected losses in high risk areas (FM December 2019 – January 2020) and other natural disasters depleting Government coffers, it will fall increasingly upon individuals to carry their own individual losses from floods. This is only likely to worsen with climate change (Read more here ).

Insurers Flooded with Claims

The Insurance Council of Australia has declared a catastrophe for property loss after receiving 21,000 claims associated with the February east coast floods with damage costs estimated to be approximately $100 million.

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Additionally, Suncorp Group announced that it had received 10 times as many claims for wet weather events like floods and storms than it did for bushfires in the period between July 2019 and January 2020. Insurance analysts predict that with more than two months left of the 2020 cyclone season, the number of claims is expected to increase (Read more here and here).

Man Rescued from Floodwaters After Clinging to a Tree for Ten Hours

The Bega Valley SES rescued a man from the Brogo River near Bega, NSW after he had been clinging to a tree for 10 hours.

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The SES responded to a callout early in the morning of 10 February, as a passer-by had spotted the man clinging to a tree in the heavily flooded river. It is unclear why the man had entered the floodwaters, with local SES Commander Michelle De Frisbom stating that: “He was suffering the effects of hypothermia”(Read more here) .

Tailoring LTFRI to Better Explain Flood Risk

The UK’s Environment Agency has used public feedback to modify its Long Term Flood Risk Information (LTFRI) service to improve its value in terms of raising public awareness and understanding of surface water flooding.

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Feedback provided during the trial phase of the LTFRI in 2016 revealed that users found it difficult to locate their property using the postcode function, and largely disagreed with the flood risk assigned to their property. The former was rectified by a newer government database using address over postcode. The reasons that users disagreed with the LTFRI classification of their property were: there was a lack of flood history at the property, they were not located close to a waterbody, they lacked understanding of flood terminology, and they were frustrated that the LTFRI could increase insurance premiums and deter potential buyers. The team behind LTFRI responded by making explicit statements about the severity of risk at the property, which agency was responsible for management, and used more relatable terms such as flash flooding. The output for each property was also updated to include recommendations of how to prepare for flooding, how people can protect their properties, and how to find out about insurance and moving house (Read more here ).

First Ever Red Weather Warning Issued in New Zealand Amid Toxic Floodwater Fears

New Zealand’s Met Service issued its first ever red weather warning after a deluge in parts of the South Island cut off roads and forced the evacuation of 2,000 people.

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Police led evacuations across the region, including the entire towns of Mataura and Wyndham, and much of the town of Gore which saw 700 mm of rain in 24 hours. There was serious concern for a paper mill in Mataura where stored chemicals could have released toxic ammonia gas if it came into contact with water. In Milford Sound, 200 tourists were evacuated by helicopter from the township after flood waters cut-off main access roads following 1,000 mm of rain which fell in a 60 hour period (Read more here).

Flooding Class Action in Jakarta Delayed as Complainant Representatives Fail to Show

On 13 January, 243 residents filed a class action against Jakartan Governor Annies (FM December 2019/January 2020), however the first hearing was delayed as three of the five complainant representatives failed to show.

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Further to this, the flood case is likely to be drawn out and complicated and is unlikely to be able to prove civil liability. Legal experts believe that the case will be judged based on article 1365 of the Civil Code which states that “any person who causes damage and/or loss to another party by means of an unlawful act must, because of his or her fault in causing the loss, compensate for that loss”. The difficulty could be proving that the Governor acted in an unlawful manner with regard to the victims of the recent floods. The complainants have two weeks to replace the missing representatives in time for the formal examination set to occur late in February (Read more here ).

Widespread Criticism as Flood Defences Fail Across the UK

In the wake of widespread flooding across the UK, many have criticised the lack of control over floodplain development and a shortage of floodplain management funding.

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Flooding in the wake of recent Storm Ciara and Storm Dennis in the UK damaged over 550 homes and cut rail and road routes across the transport network. On 16 February the Environment Agency had issued a record 594 flood warnings or alerts. In light of this, only 1% of government infrastructure spending in England is set to go towards flood defences, and this is disproportionality allocated to London and the South East of England, and not to the worse hit areas in the north of the country. Further exacerbating the number of people exposed to flooding is the fact that one in ten homes built since 2013 are built on land at the highest risk of flooding. It is likely that the increased demand for housing has resulted in the relaxation of planning laws which permits building in higher risk areas. It is estimated that 84,000 homes are already at risk following the government’s promise to build 300,000 new homes a year by the mid-2020s(Read more here, here, here, here, here, here, here, and here.

New Flood Prevention Technology Testing Facility Opens in UK

The Green Infrastructure Facility, which is funded by the Engineering and Physical Sciences Research Council (EPSRC), allows engineers to test new technologies that can slow flooding in the event of extreme rainfall.

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The ten hectare area located in Newcastle, England will host a range of natural engineering systems including green roofs, rain gardens, and a full-scale swale fitted with a series of ‘leaky barriers’ designed to hold back floodwaters. The systems will be monitored by a network of sensors and cameras designed to detect water levels, soil moisture levels, precipitation and other meteorological conditions. The data collected will be analysed by Newcastle University’s Urban Observatory, to inform future flood management decisions. Naturally engineered schemes tested at this facility are hoped to supplement and alleviate pressure on physical flood defences by dispersing excess water from extreme rainfall and reducing flood risk (Read more here ).

Wildlife Flood Evacuation Corridor

Since 2016, the Yolo County Resource Conservation District in California has been leading a project to improve flood escape for wildlife, implement agriculture-compatible restoration, and engage the public.

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The Yolo Bypass Wildlife Area (YBWA) in Sacramento Valley, California is frequently affected by winter flooding which regularly isolates deer, migratory water birds, and ground nesting bird species. The project aims to create eight kilometres of cover corridors through farmland to protect wildlife escaping flood events. The corridors are also hoped to enhance year-round habitat for migratory birds, pollinators and other wildlife, provide a public-access demonstration planting, and increase awareness and appreciation of the YBWA and its ecological values and functions (Read more here ).

Planting Perennials into Flood-Prone Areas

An article published in the American Institute of Biological Sciences has proposed planting perennial crops in flood-prone areas as a more economically sustainable alternative to annuals.

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Modern farming techniques such as wetland draining has decreased the water storage capacity of floodplains across the USA leading to a predicted decrease in annual row crop yields by up to 46%. The researchers suggest that by integrating perennials into wetter portions of the agricultural landscape, it may be possible to add water storage by removing drains from lowlands, reconnecting rivers to their floodplains, and restoring oxbows. Planting perennials may also provide farmers with a more reliable economic alternative as they are hardier in terms of flood tolerance, have a higher probability of achieving higher yield in a more frequently flooded landscape, and are beneficial in retaining soil integrity and nutrients (Read more here ).

The Levee Paradox Quantified

An article published in the Journal of Regional Climate Change has demonstrated the unintended consequences of structural flood protection in terms of increasing complacency and flood mortality.

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he researchers used the Jamuna River floodplain in Bangladesh as a case study to investigate what is commonly referred to as the “Levee Paradox”. The river has a levee which is only constructed and maintained on the right bank thus the researchers could compare the differences across a variety of factors according to which side of the river the population was sampled from. The study included a comparative analysis of rural areas with and without flood protection in terms of variables such as population density, human settlements, and flood fatalities. Results showed that population density and human settlements exposed to flooding were higher in areas of greater flood protection. Similarly, it was found that areas with better flood protection had higher rates of flood mortalities following the 2017 floods than areas with lower levels of flood protection. The findings suggest that some flood risk management approaches may unintentionally increase the risk to human life as a result of increasing complacency and instilling a false sense of security (Read more here ).

Typology of Community Flood Resilience Capacity

An article published in the Journal of Regional Climate Change sets out a typology of community flood resilience capacity to better understand the co-benefits of investments in disaster resilience.

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The researchers conducted an analysis of community characteristics and five capitals (human, financial, natural, physical, and social) to investigate the relationship between flood resilience and development conditions. The results showed that highest flood resilience capacity was found in communities with a well-balanced household income distribution. The researchers also found that stronger interactions between community capacities could help to facilitate multiple co-benefits when investing in flood resilience. The study highlighted the diversity of community types that need investment in enhancing their flood resilience, while considering the community-specific constraints in terms of human, financial, natural, physical, and social capitals (Read more here ).

Army Corps Not Liable for Downstream Flooding

In stark contrast to the court ruling of last December (FM December 2019/January 2020), the Army Corps of Engineers cannot be held responsible for flooding that occurred downstream of Texas reservoirs during Hurricane Harvey.

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Senior Judge Loren Smith has rejected landowners’ claims that the government should have ensured the protection of their Houston homes following Hurricane Harvey on the grounds that the event was “an Act of God”. The fact that the gates of the dams had been closed to ensure the protection of their homes and that “mitigation failed because the impounded storm waters exceeded the Reservoirs’ controllable capacity, and that the Harvey was the sole and proximate cause of the floodwaters” was grounds to reject their claims. The downstream landowners plan to appeal this decision on grounds that it conflicts with the ruling made for homeowners upstream of the dam in the same event (Read more here).

Comparing Top-Down and Bottom-Up Paradigms for Global Flood Hazard Mapping

The prevalence of using global floodplain maps for the identification of flood risk hotspots or the mapping of flood-prone areas is increasing, thus a recent paper has compared the most frequently used paradigms.

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The top-down paradigm is based on a definition of the floodplain as the area falling within the extent of a given flood event. These synthetic events with given probability of occurrence or return period are typically estimated via hydrological modelling or statistical analysis of flood data. Alternatively, the bottom-up paradigm floodplains are identified directly from the topography and are assumed to have been shaped by past flooding events. The researchers identify the pros and cons of both paradigms in terms of global flood hazard mapping. For example, whilst top-down paradigms have the scope to provides additional variables, such as maximum flow depth, velocity and volume they are sensitive to data scarcity, unlike bottom-up approaches, which may make them less favourable in poor-data areas. The researchers identify the opposing positive and negatives of the two paradigms and suggest a unified approach to hazard mapping to provide a more complete view of flood risk hotspots worldwide (Read more here).

International Floods

There were 22 international floods reported across 21 countries throughout February 2020. At least 77 people died and over 32,000 were displaced.

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Internationally significant floods included:

Tanzania

At least 40 people died and were 15,000 displaced following flooding in the Lindi Mwanza, Morogoro and Manyara regions, Tanzania. Flooding that began in late January destroyed 1,746 houses. Many of the affected areas are only accessible by boat with authorities fearing that the risk of waterborne disease could increase due to contaminated water sources. Elsewhere, the Nyumba ya Mungu dam located in the Mwanga District in the northern Kilimanjaro Region has overflown prompting the evacuation of 25,000 residents. (Read more here, here, and here).

Rwanda

Storms and heavy rain starting in early February have triggered flooding and landslides in the country’s capital, Kigali. At least 13 people have died and 15 homes have been completely destroyed. Emergency service boats have rescued countless people stranded due to flood water in the city and surrounding areas. (Read more here ).

Burundi

The flood situation in Burundi continued (FM Dec/Jan 2020) as 11,000 people are thought to have been displaced in several provinces including Bujumbura Mairie, Bujumbura Rural and Bubanza. Almost 10,000 of that total are in Mutimbuzi commune in Bujumbura Rural Province, where the overflowing Rusizi River has damaged or destroyed over 3,000 homes. (Read more here ).

Diary

Submissions Now Open for the Australian Institute for Disaster Resilience (AIDR) Resilient Australia Awards
Submissions close 18 May 2020
For more information visit here

Monte Carlo Design Flood Estimation Using RORB Workshop Event
Where: Perth, Western Australia
When: 24 March, 2020
For more information visit here

FRIAR 2020 International Conference on Flood and Urban Water Management
Where: Valencia, Spain
When: 11-13 May 2020
For more information visit here

2020 Floodplain Management Australia Conference
Where: Empire Theatre, Toowoomba, QLD
When: 19-22 May, 2020
For more information visit here

2020 Association of State Floodplain Managers (ASFPM) Annual National Conference
Where: Fort Worth, Texas, USA
When: 7-12 June 2020
For more information visit here

2020 International Conference on Flood Management
Where: The University of Iowa, Iowa City, Iowa, USA
When: 17-19 August, 2020
For more information visit here

FLOODrisk 2020 European Conference on Flood Risk Management
Where: Budapest, Hungary
When: 31 August – 4 September 2020
For more information visit here

Resources

Podcast and Book Discuss the Relocation of Gratham, Qld Post-Flood

An ABC conversations podcast has recently released its second instalment of the story of Grantham, Qld following the devastating floods in 2011. Part two of the podcast details the steps taken to achieve the promise made by Mayor Steve Jones to relocate Grantham to higher ground with the help of Jamie Simmons. Jamie has published a book documenting the momentous effort taken to motivate and lead a community fractured by tragedy and loss to achieve a seemingly insurmountable and extraordinary task. Listen to the ABC Conversations Podcast here. A copy of Jamie’s book can be purchased here.

Flood Planning for Disaster Resilience Handbook

The Australian Institute for Disaster Resilience (AIDR) is developing the new Flood Planning for Disaster Resilience Handbook which should be available April 2020. The handbook will provide guidance on national principles and practices in flood planning for disaster resilience in Australia and replace the four flood manuals previously published in 2009:  Flood Preparedness; Flood Warning; Flood Response; and Emergency Management for Planning for Floods Affected by Dams. (Click here).

Townsville Workshop Presentations Available Online

Floodplain Management Australia (FMA) has announced that the workshop presentations from the regional meeting in Townsville, Qld in November 2019 are now available online. The presentations relate to information regarding the devastating 2019 February monsoon floods. (Click here).

Report Examines How Cimate Change is Impacting UK Homes

The Climate Coalition report, backed by research from Priestley International Centre for Climate Change, finds that extreme rainfall has increased by 40%, and the number of people in the UK facing floods during the winter is more than the population of Birmingham and Manchester combined. The report provides information to homeowners to make their houses more energy-efficient and improve flood defences in vulnerable areas.(Click here).

Retrofitting Buildings to be More Flood Resilient

A recently published retrofitting guide offers advice on the nature of flood risk, and a visual demonstration for adapting built and natural environments to better cope with increasing flood risk. The guide includes illustrations demonstrating retrofitting options to make a home more flood resistant and recoverable. (Click here)

Floods Maps of Europe Predict Areas Likely to Become Flood-Prone Under Climate Change

A series of detailed maps based on different greenhouse gas emissions scenarios and climate models have been published by the European Environmental Agency. The maps show the future effects of key climate hazards such as floods and sea level rise around Europe and beyond. (Click here).