Floods are common natural disaster occurring in most parts of the world. What causes floods flooding occurs in known floodplains when prolonged rainfall over several days, intense rainfall over a short period of time, or an ice or debris jam causes a river or stream to overflow and flood the surrounding area. Hurricanes bring destructive storm surges, which can quickly uplift shore water by up to several meters. Also causes of flood mortality have been studied, an overview of findings from the analysis of flood cases is given in the report.
It is important also to note that flood causes may combine. Flash floods also can be caused by dam failure, the release of icejam flooding, or collapse of debris dams. Furthermore, flash floodproducing rains can also trigger catastrophic mud slides. They are caused by heavy thunderstorms and dam failures. Find out what to do before, during, and after a flood. Nature and causes of flooding and associated secondary. Insurance most homeowner policies do not cover flood damage.
In nigeria, though not leading in terms of claiming lives, flood affects and displaces more people than any other disaster. When it plunges south, it can pick up tropical moisture from the gulf of mexico and dumps it on the east coast. Provide basic information about flash floods especially focusing on differences from riverine floods. If the water level is higher than the level of the coastal lowland, flooding will occur. The health impacts of floods are wide ranging, and depend on a number of factors. Flooding occurs in known floodplains when prolonged rainfall over several days, intense rainfall over a short period of time, or an ice or debris jam. Flash floods can lead to larger floods, but these are shortterm, localized flood events. During floods, rivers have the ability to raise the level of bottom sediments. However, the health impacts of a particular flood are specific to the particular context. For prevention of flood health effects more insight in the causes due to which flood deaths occur is necessary. Severe floods not only ruin homes businesses and destroy personal property, but the water left behind causes further damage to property and contents. If there happened to be a flood in your area, protecting your home could end up saving you a lot of money as well as the stress and hassle. This paper identifies the fundamental causes of the frequent floods and debris flow.
Everyone has a responsibility to protect their homes and their families. Year by year, theyare the most dangerous, disruptive events affectingmany peoples lives, and are the most expensive interms of property destruction and repair costs. Therefore the responsible authorities should provide timely and reliable flood warning, flood. Floods generally develop over a period of days, when there is too much rainwater to fit. Flood hazard ironically, the same river or stream that provides. A flood is defined as water overflowing onto land that usually is dry. Flash floods often come from intense storms and the overflowing of small rivers and creeks. The longterm 1940 to 1999 annual average of lives lost is 110 per year, mostly as a result of flash floods.
Flash floods are floods that rapidly submerge lowlying areas in under 6 hours. This study will examine, in particular, thailands 2011 flood since it is the most notable example of the impact of floods both on industries and the whole. Main causes of flash floods in the european mountains presentation is published by svetoslav apostolov with the aim of enhancing public access to information on the main causes and effects of floods and in particular of flash floods in the mountains of europe, as well as the most important preventive and. The causes of flooding are varied, but the effects of most causes can be managed if not prevented. Integrated flood management tool series executive summary 1 the purpose of this document is to provide an overview of the actions that can be taken to manage and minimize the potential impacts of flash floods. Background paper prepared for the global assessment report. Dss floods page 4 of 23 construction in floodprone areas there is a worldwide trend that more and more people take up residence in areas vulnerable to floods abi. Well, in the aftermath of the floods, teachers at hebden bridge school invited local kids to find out causes of floods. Pdf in august 2001, the worst flash flooding event of the caspian sea regions in over two centuries.
Floods and flash floods happen whenever water overflows onto normally dry land. Nearly all of the largest floods caused by rainfall have occurred in basins south of latitude. Describe the causes, probabilities and impacts of floods. Combining flood reconstructions with climate reconstruc. High tide combined with a stormy weather and low atmospheric pressure is one of the main causes of flooding in coastal regions. Flash floods also occur after dam and levee failures. But while the outcome is the same, and the weather events that cause them slowmoving lowpressure systems, hurricanes, and monsoons may be the same, all floods are not created equal. In urban areas, flash flooding can occur where impervious surfaces, gutters and storm sewers speed runoff. Lead teacher anil sarna asked his local year 5 and year 6 pupils to see if they could work out what causes flooding, testing what they learnt using a series of experiments. Causes of floods an exercise matching flood causes and explanations and a investigation of flood intensifying conditions.
Integrated flood management takes account of those expected effects, and is therefore an autonomous adaptation strategy to climate variability and change. Pdf causes and consequences of recent floods in the golestan. Pdf causes and consequences of flooding in nigeria. Pdf anthropogenic factors that cause floods in mukuru.
The environment and wildlife is also at risk when damage when damage to businesses causes the accidental release of toxic materials like paints, pesticides, gasoline etc. Outside the mountain part of the basin, especially in the san river catchment, floods are also caused by intensive snowmelt. Pdf flood generation mechanisms and changes in principal. Preparation is the key to surviving a flood and reducing property damage. A print screen windowshowing task performed on each spatial data layer in arc. This is because rivers flow more slowly in lowlying areas.
Natural processes, such as hurricanes, weather systems, and snowmelt, can cause floods. The causes of floods are increased precipitation, regulation of releases of reservoirs, global warming, overflow and destruction of dams. Urban slums are facing increased challenges of flooding scenarios that hinder their development. Flowchart showing methodology to merge layers and overlay with study area32 figure 17. If the water volume increases suddenly, floods occur. We will explain floods causes effects and prevention by using different types of flood defence systems. A print screen windowshowing task performed on each spatial data layer in. River systems and causes of flooding tulane university. Flash floods occur within a few minutes or hours of excessive rainfall, a dam or levee failure, or a sudden release of water held by an ice jam.
These floods are generally expected and welcomed in many parts of the world, since they enrich the soil and provide both water and livelihoods. A flood is caused by a combination of heavy rainfall causing river oceans to over flow their banks, and can happen at any time of the year, not just in the winter. Floods are among the most devastating natural disasters in the world, claiming more lives and causing more property damage than any other natural phenomena. High tides or storms cause the water level to rise.
Case studies recent flooding in argentina free download as powerpoint presentation. Floods causes effects and prevention stormguard floodplan. The arctic is warming faster than the temperate zones. Its effectiveness depends on the level of preparedness and correct response. Melting snow can combine with rain in the winter and early spring. They can form a dam in the river, causing the water behind the dam to rise and flood the land upstream. Although in cold winter areas where snowfall accumulates on the surface, substantial flooding frequently occurs during the period of melt in spring and. The cause of flooding also varies by geographical location. Excessively heavy and or excessively prolonged rainfall is the most common universal cause of floods. Continuous heavy rainfall will cause an increase in surface runoff, increasing the volume of flow in a river as it exceeds its carrying capacity and overflows, resulting in flooding. Case studies recent flooding in argentina flood flood. With the exception of an unusually large flood in 1987, large floods have increased by about 100 percent from about 1,000 cubic feet per second to about 2,000 ft3s while small floods have increased by about 200 percent from about 400 ft3s to 1,200 ft3s. They flow into areas where flood waters are unnecessary, destroying infrastructure and in severe cases, ending lives. Flooding is often thought of as a result of heavy rainfall, but floods can arise in a number of ways that are not directly related to ongoing weather.
Especially in european floods, the loss of life is to a large degree associated with risktaking behaviour. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Forests and floods food and agriculture organization of the united. Flooding is arguably the weatherrelated hazard that is most widespread around the globe. Sewage treatment plants, waste dumps or dangerous industries located at very low spots in. Annually in the world, there are a lot of floods, in the spring of 2017 they were especially catastrophic in kazakhstan. Rivers that are covered in ice can also lead to flooding. Consequences of droughts glossary bibliography biographical sketch summary drought is one of the most damaging environmental phenomena. Best practices on flood prevention, protection and mitigation 3 flood forecasting and warning is a prerequisite for successful mitigation of flood damage.
Rapidly rising water can reach heights of 30 feet or more. Regular floods are part of peoples lives in various regions of the world, recurring with varying magnitudes and frequencies to which people have adapted for centuries. Flash floods can roll boulders, tear out trees, destroy buildings and bridges, and scour out new channels. When ice begins to melt, the surface of the ice cracks and breaks into large pieces. Heavy rainfall at river sources unusually heavy weather at the source of a river can lead to vast amounts of water draining into the water table. Increase in the inflow of water into rivers and lakes is caused by heavy rainfall that occurs at some point along their course with the heaviest effects being felt downstream where the river starts to flatten out and slow down. Floods flooding causes more than 90 percent of disasterrelated property damage in the u. Causes of flooding from a geological perspective, floods are a natural consequence of stream flow in a continually changing environment.
Flood impact analysis using gis a case study for lake. You can greatly lessen the impact of a flood by taking the time to prepare in advance. Worksheet on causes of flood notes linkedin slideshare. That can change the air pressure and turn the jet stream. Flash floods often pose the greatest immediate threat to animals and people because they can be trapped and drown. Although flooding is a natural phenomenon caused by antecedents such as melting of icebergs, hurricanes, overfilling of the major rivers, many other flood types are humancaused. Climate change may also cause floods by shifting the pattern of the jet stream. Flash floods rank first as the cause of floodrelated deaths in the united states. Increased flooding events in informal urban settlements can be attributed to humankind alteration of the environment.
When floods occur they bring with them numerous problems, ranging from the physical impact of water damage to the problems of disease and famine that can follow such disasters. You will not always have a warning that these deadly, sudden floods are coming. Nature and causes of floods and associated secondary hazards throughout history people have been attracted to the fertile land of the flood plains where there lives have been made easier by virtue of close proximity to sources of food and water. The worlds largest floods, past and present usgs publications. Failure of levees and dams and inadequate drainage in urban areas can also result in flooding. Hurricanes, clogged drainages, and rainfall are some of the conditions that have led to flooding in various regions across the globe. Other impacts from flooding are growing more steadily over time. Rain is the leading contributor to most of the flooding cases witnessed across the world. Flash floods follow heavy rainfalls in lowlying and drainage areas and in areas where irrigation is not adequate. The goal of this paper is to investigate the impact of floods on the global economy through supply chains, and to propose what components should be considered to measure supply chain risk.
This causes them to spill water over their banks, and eventually, the water starts flowing over the adjacent land causing floods. Floods can be caused by natural processes in the atmosphere andor human activities which influences the environment. In general, drought is a temporal reduction of environmental moisture status relative to the mean state. This is a ks5 as resource but could equally be used with a ks4 class for homeworkrevision. Floods have been occurring throughout earth history, and are expected so long as the water cycle continues to run. Floods occur when water overflows and unintentionally escapes places such as lakes and dams. Main causes of flash floods in mountains authorstream.
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