Flooding hazards can be divided as primary, secondary and tertiary. Primary hazards are those that occur due to contact with flood water. Secondary effects are those that occur as direct effect of flooding such as disruption of services (such as power interruptions) and health impacts such as famine and disease. A sample of a tertiary effect, on the other hand, are changes in the position of river channels. Flooding is considered to be one of the most devastating disasters in terms of cost as reflected to property damages and life casualties. Major floods in China had surfaced a number of casualties: 2 million people in 1887, 4 million in 1932 and about 1 million in 1938. Another destructive flood is that of the Upper Mississippi River, despite only 47 people were killed, an economic loss from 15 to 20 million dollars was estimated.Direct contact with flood waters compromises the primary effects of floods. Floods with an increase of discharge increases velocity, and with higher velocities, streams could transport large particles such as rocks and sediments. Floods can cause erosion, wall, floor and furniture damages. Flooding in farmland can results in crop loss. Livestock, pets and other animals are often carried away and drown. Even humans can get carried away and drown. It could also concentrate on garbage, debris and toxic pollutants that can cause secondary effects.

Secondary effects are direct results of the primary effects. Basically, these are disruption of services. Pollution of drinking water is the greatest example and it can cause diseases especially in under developed countries. Gas and electrical service may also be disrupted, as well as transportation systems. Disruption of transportation systems can even lead to shortages of food and clean up supplies.

Tertiary effects are the long term changes that take place due to flooding. Location of river channels may change as the result of flooding, new channels develop, leaving the old channels dry. It can also lead to the destroy of farmlands due to sediment deposits. Jobs may be lost due to the disruption of services and destruction of business. Destruction of wildlife habitat is another effect.

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Known as a dike in European countries, a levee is basically a flood bank or slope that runs parallel to a river. Either natural or man made, a levee helps protect an area from being flooded by serving as a protective dam or  wall to the rising river during heavy rains.

However, there are times when levees fail. Sometimes the water from the river is so strong that an actual part of the levee breaks resulting to a whole where the flood water rushes in. This kind of levee failure is referred to as a levee breach and is considered very dangerous. At times water from the river flows over the levees causing massive flooding on the other side. The problem with levee overtopping is that it causes further damage to the levee which can lead to a complete breach.

In the US, most of the levees across the country were manmade, having been constructed for both agricultural and flood protection purposes. A lot of the levees are old with some are even more than centuries old. Early this year, the US Army Corps of Engineers reported that 146 levees in the US were already in a sad state and are at risk of failing if a major flood occurs.

In 2005, the country saw the devastating effects of levee failure when Hurricane Katrina passed through New Orleans. The rains brought by the storm resulted to more than 50 levee breaches and water overtopping. Almost 80% of the city went underwater as a result, caused vast damages in properties, and lost of human lives.

Other historical levee breaches include the Great Mississippi Flood in 1927 where the Mississippi River breached levees and flooded 27,000 square miles (70,000 km²) in seven states, displaced more than 700,000 residents, and killed 246 people; the 1953 North Sea flood levee breach in the United Kingdom and the Netherlands which killed more than 2,000; and the Jones Tract island levee breach in Sacramento-San Joaquin Delta which happened just a year before Hurricane Katrina.

A typical levee should be at least several feet high and wide. The advantage of a levee over a flood wall is that with a solid foundation or base, one can increase its height temporarily by stacking sandbags or water-inflated dams on it.

When building a levee, it is important that the sloping surface be protected from erosion. To prevent, this engineers plant the slopes with grass or shrubs. Also, aside from erosion levees can have problems with burrowing animals and tree roots. The integrity of the base is compromised with tunneling from the animals which increases the risks of breach.

Moreover, you need to understand that a levee may very well keep the rising river from flooding an area but in cases where overtopping occurs, the levee becomes an enemy as well. When the area becomes flooded, the levee traps the water inside the levee.

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About 80 years ago, one of the worst flooding in the history of the United States devastated seven states and placed more than 26,000 square miles of land under water. Affected were the states of Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri and Tennessee.

The 1927 Mississippi flood began a year before when torrential rains fell in the region. The area experienced extraordinary heavy rains during the summer of 1926 and went on through winter until spring. The record rains was ten time more than the previous years. The Mississippi river is known to overflow its banks on a  regular basis. But because of the heavy rains, floods began to occur in the lower Mississippi area during the early months of 1927. And every time a flooding occurs, it bested the previous one in magnitude, area covered, and damages incurred.

By February 1927, the Mississippi has inundated more than 100,000 acres with ten to fifteen feet of water. The coverage grew to as big as one million acres of land by April 9. And yet the rains still continue to fall. The US Army Corps of Engineers assured the public that the levees that they built to control the regular rise of the Mississippi would hold. But this was no ordinary rise in the water level of the river.

On April 15, 1927, more rains came. The rainfall was already a record high and yet there seems to be no break from the downpour. Rains fell in the states of Missouri, Illinois, Arkansas, Mississippi, Texas, and Louisiana.

Soon the river overpowered the levees which the Army has, at some areas, stacked up from an original 7 feet to as high as 38 feet. Nature again proved that she is more powerful than man. One of the biggest breaks in the levees was at Mounds Landing where the water from the river flooded an area more than 50 miles wide and 100 miles long. Trees, cotton fields, houses and infrastructure, and whole communities went under 20 to 30 feet of water.

The flood waters began to withdraw back to the river by July 1. However, more than 1.5 million acres of land was still under water. Even so, the river still measured an unbelievable 70 miles wide.

The 1927 Mississippi flood is permanently written down in history as among the worst mother nature dished at us. The flood waters claimed more then 500 lives, and made more than 700,000 people homeless, not to mention the millions in damages it brought to the infrastructure and agriculture in the area.

There were a number of socio-political issues that came out because of the 1927 flood. Among them was the maltreatment of Southern blacks in the refugee camps. The floods also catapulted then Secretary of Commerce Herbert Hoover to the presidency since he was in charge of the flood relief operations. He got the blacks’ vote when he promised reforms for their better treatment but lost it four years later in his reelection bid when he broke most of his promises.

Posted in Floods

A lot of areas in UK are at high risk of being flooded. The series of floods that hit England and Whales these past few months is a testament to that fact. There are an estimated 5 million people and around 470,000 properties in England and Wales situated in flood risk areas.

Floods have always been a major issue in Britain because they happen quite frequently, affects a large number of people, wrecks considerable amount of properties, and are very very costly.

June 2007 was one of the wettest months in the history of the UK and the above than average rainfall brought forth floods after floods, causing an estimated damage of £2billion. But the bad thing in this situation is the fact that things will get worse in time. With the climate changing quite drastically in recent years, it is expected that similar wet months are to be expected in the next forty years.

Having this foreboding scenario in their midst, the Department for Environment, Food and Rural Affairs or Defra launched a new scheme to protect or at least minimize the effects of households from the devastating effects of floods. The government offers individual households grants for improving their own flood defenses.

Improving the properties’ flood resilience can protect them from major damage in case of floods. Flood defenses include setting up flood guards, tiled concrete floors, resilient plaster, and raising electrical appliances on a higher grounds or platforms.

Installing one-way valves into drainage pipes is also useful. This way, the water and sewage is prevented from backing up into the house during floods. If you have any chipboard appliances or units, it is best to replace them with plastic or steel since later materials will not get soggy when they get wet. .

Reposition your electrical sockets higher up the walls. Use lime plaster or cement render to re-plaster the inner walls. These plaster are made from water resistant materials.

Speaking of water -resistant, the doors and window frames could be made from UPVC or good-quality hardwood to make them more resilient to water. Place barriers on your doors, windows and airbricks. A pump system can also be used. The pump would get the water from the first floor once the water starts to get in.

Defra split £500,000 between six areas as part of the pilot flood resilience program. The areas are Uckfield in East Sussex, Bleasby in Nottinghamshire, Morecambe in Lancashire, Halton in Leeds and Kirkby-in-Furness and Appleby in Cumbria.

Another problem with having areas and properties flooded all the time is when applying for home insurances. It has been reported that due to the massive damage of recent flooding in the UK, insurers are no longer willing to give homeowners low premiums on house insurance payments.

According to reports, it is quite possible that the value of houses affected and damaged by the floods would decrease by as much as 80%. This is due to the refusal of insurers to cover their houses because of possible future claims of the same nature.

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Communicable diseases are, simply put, contagious diseases. They are any disease that can be spread through the air, by direct contact or through contaminated body fluids. Some examples of communicable diseases include diarrheal diseases, tuberculosis, malaria, measles, pertussis, tetanus, meningitis, and hepatitis B.

How do these diseases relate to floods? Well, floods can readily increase the spread of communicable diseases, but not all of them. We can classify the diseases transmitted during flood disasters into water-borne and vector-borne diseases. Some of the more common water-borne diseases include typhoid fever, cholera, leptospirosis and hepatitis A. Meanwhile, vector-borne diseases include malaria, dengue and dengue haemorrhagic fever, yellow fever, and West Nile Fever.

Water’s the culprit
Obviously, when flooding occurs there is an increase risk of water-borne diseases going around due to the excess water from the floods. Moreover, the risk increases in relocation areas or areas where people are housed temporarily due to the fact that they were forced to abandon their homes because of the flood waters.

One of the major considerations during floods and mass displacement of people is where to get clean water supply. Because floods can easily contaminate drinking-water facilities, diseases like diarrhoeal diseases and typhoid fever can easily become an outbreak.

Also you need to look after other infections that could result from polluted waters. Wound infections can be one of them, dermatitis, conjunctivitis, and even ear, nose and throat infections can become a problem.

Floodwater could also lead to leptospirosis, which is a bacterial disease that come from urines of rats. Once rat urine mixes with floodwaters, the soil or even vegetation, any contact to the skin could result to the transference of the bacteria.

The air could be a problem
Aside from the contaminated waters, there are other diseases, specifically vector-borne diseases that can easily hit an flood affected area. A vector-borne disease means it is transmitted by vectors to humans. Vectors here refers to any animal capable of transmitting the disease.

So in case of flood calamities, probably the most notorious animal that spreads diseases is the mosquito. Due to high chances that standing water exists inside or near the flooded areas, if is expected that mosquitoes would breed in the millions. Although, the risk of being contaminated via mosquitoes is far less during a flood than after one. After the floodwater subsides and everything settle down, the risk increases.

The most common vector-borne disease during flooding include Malaria and the West Nile.

Other flood related risks
During floods, the risk of drowning, having injuries and trauma are higher. Be careful during wading on flood waters and also maneuvering yourself in flooded ares. Also, watch out for hypothermia. Long exposure to the cold floodwaters can easily lead to it. Children are more prone to hypothermia than adults.

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The recent flooding in the UK, Bangladesh, India, Korea, Indonesia, and now Africa has displaced quite a number of people, damaged a lot of public and private properties, destroyed agricultural crops and livestocks, and crippled the economy of countries.

But the news of these obvious destructions and the lost in human life are not the only effects that we should worry about from flooding of this magnitude. It is what happens after the water subsides that we really begin to feel that what happened was a disaster. The outbreak of diseases are of great concerns when floods occur especially in hot countries were illnesses easily spreads.

During floods, one of the most likely disease to strike first is cholera. By relocating huge numbers of people and cramming them in small confined areas, sanitation would certainly become a problem. The water and food supplies would become contaminated and people would likely develop infection of the gut causing chronic diarrhea and vomiting, both symptoms of cholera.

Frequent diarrhea and vomiting would then cause severe dehydration that can lead to a lot of things, the worst case being death. and, in extreme cases, death.

A partner of cholera is dysentery which is caused by parasites also from contaminated food and water. Nausea, loose bowel movement, weight loss, and occasional fever are the general symptoms of dysentery. Each one is potentially dangerous in itself, thus combining the two is really deadly.

The treatment of cholera and dysentery are through antibiotics but since drugs don’t work that fast because of the resilience of the disease. Therefore, in cases where flood victims are diagnosed with cholera and dysentery, immediate rehydration would be the best approach to save their lives. But of course, improving sanitation in the evacuation areas and making sure that the water and food supplies are clean are the best ways to avoid a epidemic to occur.

Airborne disease are the next wave of disease that would most likely hit your relocation areas once the floodwaters go down. Stagnant floodwaters, and the marshes created by the flood are perfect breeding ground for mosquitoes and other insects.

Malaria and dengue fever are highly possible. Some of the symptoms of Malaria include high fever and chills. The disease can be treated but when left alone can easily lead to death. Mostly infants, children, and pregnant women are affected by Malaria and dengue fever.

Malaria, dengue fever, cholera and dysentery are but a few of the disease that can easily rise from flooding situations. There are more waterborne and vector borne diseases out there, some unique in certain countries while others don’t choose victims, bu all are potentially dangerous and can easily increase the plight of already suffering victims.

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The recent flooding in the UK left a lot of homes and properties damaged. But some residents are finding it difficult to move on with their lives especially with the issue of insurance renewals hanging over their heads.

A particular news item brought this issue to my attention. Apparently, a couple in Worcester got their homes flooded when River Severn overflew. The couple’s living room and downstairs bathroom were overwhelmed by flood waters late last month. Now the couple was scheduled to renew their policy a week after their home got flooded.

It was not surprising that the insurance company would be increasing its excess but the couple was quite shocked to hear from the insurance company that their home insurance grew from £50 to £10,000 due to the floods. Moreover, the renewal contract states their home will not be covered unless they set up temporary flood barriers. Fortunately for the couple, and probably with the help of the story being publicized and broadcasted in popular media, the insurance company took a second look at their policy and decided to reduce the amount to £1,000.

A good home insurance can help you stand up on your own feet again even after experiencing such natural tragedies like floods. When it comes to insurance policies, there are only two kinds of insurance that can cover the losses and damages due to floods. First is the homeowners’ insurance policy and the second is the flood insurance policy. Each one can back the other when it comes to covering losses and damages. If it is not covered by your homeowners’ insurance, it should be covered by your flood insurance and vice versa.

The coverage of flood insurance policies depend on the policy limit. However, insurance policies distinguish flood damage from any other water damage by adhering to a strict definition of floods. Insurance companies define floods as the “rising and overflowing of a body of water into normally dry land.” They give emphasis to the word “rising”and use it as a major element to determine if a particular home was damaged by flood waters or not. Also, another prerequisite is that flood damage should not be isolated to your house but also have affected  the nearby houses as well.

Insurance policies include in their floods list the various river overflows, seeping of surface water caused by heavy rain into basements or ground floor areas, and mud slides caused by heavy rains or flash floods.

Meanwhile, a homeowners insurance policy does not insure your homes from damages caused by flooding. It does, however, cover damages caused by other water related incidents. Such incidents include hailstorms breaking windows allowing hail and rain to enter the house causing considerable damage to the house’s fixtures, water damage from rain soaking through the roof, and damage from broken water pipes causing water damage to your home.

Please note that flood insurance does not replace your homeowners insurance policy. It is there to complement your existing homeowners insurance

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The collaboration of inter agencies, in particular the National Center for Atmospheric Research (NCAR) in the US, Georgia Institute of Technology, and the Asian Disaster Preparedness Center (ADPC), have resulted into developing a new system of forecasting floods. By combining elements of weather forecasts, satellite observations, river gauges, and hydrologic modeling techniques, the system can predict when major rivers would start to swell providing relatively advanced warnings for people that would likely be affected by the rising waters.

The forecasting system has been operational for the past few years. The scientists at the NCAR have been providing flood forecasts to countries that really need them. Bangladesh, for example has been receiving flood forecasts since 2003.

But it was only recently that flood forecasts in Bangladesh made major progress. The forecasts were properly utilized thanks to the efforts of local volunteers, government personnel, and non government organizations  who disseminated the information on the community level. Thus, the forecasts from the NCAR finally were able to reach the target communities allowing proper actions to be taken.

Previous flood warnings in Bangladesh come within 48 to 72  hours before floodwaters begin to put most of the region under floodwater. Today, the ADPC through the help of satellite imaging and advance weather forecasting from NCAR and other related agencies are able to issue 10-day flood forecasts. This gives the million residents of Bangladesh ample time to leave their homes and relocate to higher grounds.

This also gives support groups and local organizations to come up with the sufficient supply of food and water that would be needed once the actual floods come in and relocations areas become full with affected residents.

The cornerstone of the flood forecasting system is the Goddard Space Flight Center (GSFC) of NASA. Since its establishment in 1959, the center was vital in space and Earth science studies.

With the help of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center, the GSFC is able to create satellite images and set them against weather forecasts. Part of their resource also include weather predictions for South Asia  the European Center for Medium-Range Weather Forecasts.

Also vital in the flood forecasting system are tools both on the ground and on the base of operations. Tools like measures the water levels, radar network, equipment that measures amount of rainfall, and the computer hardware and software that plots possible speed and direction of flood or river waters.

The information gathered by the whole system is updated regularly with emphasis given to fresh information both from the grounds and satellite data imaging. This ensure that forecasts remain factual and as accurate as possible.

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You’ve heard of or have read about the word “floodplain” before, maybe in this site, in news articles, or in any other sites. But what is a floodplain? It is actually a flat area of land that is next to a stream or a river that is frequently or occasionally being flooded. The flat area of land can either be dry or semi-dry area, but as long as water naturally flows in these areas when water levels rise, these areas are considered as floodplains.

The frequent flooding of an area help shape the floodplain itself. But erosion and aggradation are usually the two main elements that create floodplains. There are times when rivers or streams cut deeper into its channel creating a narrow channel with little or no floodplain. There are times, however, that rivers and floodplains have no defined lines. Instead of a clear river bank, the land area on either side of the river or stream is so flat that the water just flow to it from time to time.

Naturally occurring floods from the rivers and streams carry sediments. Depending on the flow of the river, sediments are deposited into the floodplains differently. If the river is both deep and fast, more sediments are carried into the floodplain when the water overflows. Most floodplains are made up of sand, silt, and clay which what rivers normally carry. However, when rivers are really fast, instead of sediments in the form of silt and sand, gravel is deposited in the floodplains. As the river change its position, so do the kind and amount of sediments being deposited.

Mainly due to the rich mineral deposits that are contained in the river sediments, the floodplains support a diversity of ecosystems. Microscopic organisms alone thrive in the organic matter. The decomposition and production of nutrients make the floodplains a vital agricultural piece of land. This is one reason why people form settlements in floodplain areas despite the dangers of being flooded. The land here remains fertile for a long time.

Moreover, people build their homes and even towns on floodplains because water is more valuable in this areas, transportation through the river is cheap, and because it is basically easier to develop a flat land area than a rolling hills one. Because of these reasons, people endure the yearly or more frequent river overflow. To them the danger and inconvenience is worth it.

One of the more prominent floodplains is the one in the lower Mississippi River which is about 16 km (10 mi) across. The floodplain the is fed by the Nile River is another example of a large one.  This one is located in the upper part of the Nile Basin. The Ganges and Brahmaputra rivers in India and Bangladesh have caused countless of problems to the millions of people that live in the flood prone areas. The Yangtze River in China is another large river and large floodplain that supports a huge part of the country’s poor population.

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Flood warnings work best if they remain simple. Placing too complicated definitions behind warning signals only causes confusion among the public. This is why some governments failed in their flood warning systems. Also a factor is the process on how they arrive with specific warning signals. Agencies and other organizations involve in the overall government flood control and warning network might not have understood the full concept of their own warning system causing inadequate or wrong warning information.

Despite the arid and desert-like perception of Australia, its river system can cause major flooding. That’s why the government has instituted The Bureau of Meteorology to provide flood warning services. Their flood warning system is a product of an inter-agency cooperation involving the State Emergency Service (S/TES) in each State/Territory as well as water agencies and local Councils.

The Bureau is responsible in providing a  variety of information including Alerts, Watch or Advice notifications of possible flooding or if flood producing rains are to be expected in the next few days.

They can also issue a Generalised Flood Warning which informs the public if a flooding is occurring or is expected to occur in a particular region. As a generalized warning, it only provides information on the possible or current location of flooding and none on the severity of the floods.

With regards to flood specifics, the Bureau provides Minor, Moderate or Major flood warnings which are specialized warning systems. This time, the warning specifies the the river valley, the locations expected to be flooded, when it is likely to occur, and the expected degree or severity of the flooding.

Minor flooding is defined as floods that cause inconvenience and low-lying areas that are near waterways are expected to be affected. It is recommended that stock and equipment be removed or placed on higher grounds. Also, minor flooding warnings can mean that minor roads would be closed and low-level bridges submerged.

A Moderate flooding warning on the other hand, contains all the possibilities of a Minor warning with the addition of the evacuation of some houses due to the increase height of flood waters. Main traffic roads may be flooded and a wide range of low lying areas would be submerged.

Major flooding involves the extensive flooding of rural areas and even urban areas. Properties and towns are likely to be isolated since major roads are most likely to closed since flood waters have put down underwater. Expect people from flood infected areas needing evacuation.

Aside from the warnings above, the Bureau is also expected to provide information and predictions on the height of the river and its expected height over a time period. If you think about it, this information is very essential since it can determine if how long areas have before the rivers swell and flood their homes.

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