From the University of Southampton , word that mostly increased flooding is a reporting bias due to proximity, much like we have a reporting bias in tornado counts because there are more people to witness them than 50-100 years ago and greater urbanization.
Increase in reported flooding a result of higher exposure
A rise in the number of reported floods in the UK over the past 129 years can mainly be explained by increased exposure, resulting from urban expansion and population growth, according to new research by the University of Southampton.
In one of the most comprehensive studies of its kind, scientists have discovered that although the number of reported floods has gone up during the 20th and 21st Century, this trend disappears when the figures are adjusted to reflect population growth and increased building numbers over the same period.
Published in the journal Hydrological Sciences, the study looks at data sets from 1884 to 2013 and found an upward trend in reported flooding, with flood events appearing more frequently towards the end of the 20th century, peaking in 2012 when annual rainfall was the second highest in over 100 years.
The rise in UK flood reports over the 20th Century coincides with population growth from 38.2 million to 59.1 million and a tripling in the number of houses, from 7.7 million to 24.8 million.
“As a result there were more properties exposed to flooding and more people to report flooding,” says lead author Andrew Stevens. “A higher exposure to flooding will result in more reported flood events and larger potential damages.”
The study found significant variation between decades in both the raw and adjusted data, with the years between 1908 -1934, 1977 – 1988 and 1998 – 2013 featuring a relatively high numbers of reported floods.
The effect of increasing and improving flood defences is unclear. While upgrades to artificial defences, like the Thames Barrier, have reduced the effect of extreme sea level events, natural flood defences may have declined over the study period.
“Attributing periods of reduced flood damage simply to the effects of improved management is difficult and must be done with care,” says co-author Derek Clarke.
Professor Robert Nicholls adds “These observations should not stop concern about future flood impacts, especially in coastal areas where faster sea-level rises are expected and areas potentially exposed to higher rainfall intensities. Future flood risk may be very sensitive to changes in funding or management approaches and this has important implications for decision makers.”
The paper:
http://dx.doi.org/10.1080/02626667.2014.950581
Trends in reported flooding in the UK: 1884–2013
Andrew J. Stevens, Derek Clarke & Robert J. Nicholls
Abstract
A long term dataset of reported flooding based on reports from the UK Meteorological Office and the UK Centre for Ecology and Hydrology is described. This is possibly a unique dataset as the authors are unaware of any other 100+ year records of flood events and their consequences on a national scale. Flood events are classified by severity based upon qualitative descriptions. There is an increase in the number of reported flood events over time associated with an increased exposure to flooding as floodplain areas were developed. The data was de-trended for exposure, using population and dwelling house data. The adjusted record shows no trend in reported flooding over time, but there is significant decade to decade variability.
This study opens a new approach considering flood occurrence over a long timescale using reported information (and thus likely effects on society) rather than just considering trends in extreme hydrological conditions.
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Another issue, is that the UK (or parts of it) has been through quite a dry period over the past few decades.
People forgot what areas flooded, staff in the EA & Local Planning Authorities who had experienced flooding in the past, had retired.
The actual reason (which they won’t admit) is that the ecologists in and around the agency wanted to keep water levels high so they could be sure of having a strong spring pulse to flush out the river, like nature used to do.
And a friend of mine who lives in Oulton Broad (Lowestoft) ttold me there’s a new housing estate to be built, you guessed it, on yet another flood plain. Are all these planning offices filled with morons???
Paved parking lots should be banned in urban areas, they should all be gravel or some other water permeable surface.
Many areas in the US experience the same problems as does the UK.
Flooding, especially “flash flooding”, is the best “natural” regular dredging of a river that is possible.
But “alas”, over the past 100 years, more n’ more development has occurred in the “flood plains” of said rivers and consequently, dikes, levees and flood control dams have been constructed to protect said development. Such structures slow up the “water flow” permitting the particulate in the water to settle out, thus filling up the river channel. But, the filling up of the river channel only serves to exacerbate the next flooding event.
Worse yet, state and federal agencies have refused to appropriate funding for the dredging of creeks, streams and rivers and to add “insult to injury”, ….. the enviro whakos have gotten laws passed making it illegal, with fines and jail terms, for anyone found guilty of “mudding the waters” of any creek, stream or river. Thus, private citizens are prohibited from doing any said dredging or from the removing of any obstructions from said waterways.
And as the creek, stream and river channels “fill up”, the natural “pooling” of the water decreases ….. and the aquatic life therein suffers drastically and will eventually “die out”. And thus an entire “eco-system” that was dependent upon said “water pooling” becomes extinct. And the loss of said “water pooling” also exacerbates the loss of the “water table” …. and thus public and private “water wells” start degrading and/or “drying up”.
Dungowen in NSW is having homes destroyed with the fears the walls of their dam is weak. Well they should reinforce it. The same happened in the last Brisbane flooding, they released too much water, and Cork too. Yes you are right if you build on a flood plain one would believe is risky, and insurance companies might object. Better than building near a volcano though. But Brisbane is a flood plain. Some of these developers need the brain’s read.
Peter;
“irregular monotony”. God’s gonna gitcha fer that!
;p LOL
They ,re called Flood Plains not Climate Change Plains.
You can build on them certainly cant get building insurance on them.