How to Control Floods - (2023)

Flood control - Wikipedia, the free encyclopedia

Flood control
From Wikipedia, the free encyclopedia

Flood control refers to all methods used to reduce or prevent the detrimental effects of flood waters.[1]

1 Causes of floods 1.1 Severe winds over water 1.2 Unusual high tides 1.3 Tsunamis 1.4 Influence of urban planning 2 Effects of floods 3 Control of floods 3.1 Methods of control 3.1.1 Dams 3.1.2 Self-closing flood barrier 3.1.3 River defences 3.1.4 Coastal defences 3.2 Flood control by continent 3.2.1 Americas 3.2.2 Asia 3.2.3 Europe 3.3 Flood clean-up safety 3.4 Future 4 Benefits of flooding 5 See also 6 References 7 Further reading

A weir was built on the Humber River (Ontario) to prevent a recurrence of a catastrophic flood.

Causes of floods
Floods are caused by many factors: heavy rainfall, highly accelerated snowmelt, severe winds over water, unusual high tides, tsunamis, or failure of dams, levees, retention ponds, or other structures that retained the water. Flooding can be exacerbated by increased amounts of impervious surface or by other natural hazards such as wildfires, which reduce the supply of vegetation that can absorb rainfall. Periodic floods occur on many rivers, forming a surrounding region known as the flood plain. During times of rain, some of the water is retained in ponds or soil, some is absorbed by grass and vegetation, some evaporates, and the rest travels over the land as surface runoff. Floods occur when ponds, lakes, riverbeds, soil, and vegetation cannot absorb all the water. Water then runs off the land in quantities that cannot be carried within stream channels or retained in natural ponds, lakes, and man-made reservoirs. About 30 percent of all precipitation becomes runoff[1] and that amount might be increased by water from melting snow. River flooding is often caused by heavy rain, sometimes increased by melting snow. A flood that rises rapidly, with little or no advance warning, is called a flash flood. Flash floods usually result from intense rainfall over a relatively small area, or if the area was already saturated from previous precipitation.

Severe winds over water
Even when rainfall is relatively light, the shorelines of lakes and bays can be flooded by severe winds—such as during hurricanes—that blow water into the shore areas.

Unusual high tides
Coastal areas are sometimes flooded by unusually high tides, such as spring tides, especially when compounded by high winds and storm surges.


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Flood control - Wikipedia, the free encyclopedia

Tsunamis are high, large waves, typically caused by undersea earthquakes, volcanic eruptions or massive explosions.

Influence of urban planning
Adeloye & Rustum (2011) analyse the causes of the flooding problems being encountered to recommend sustainable management solutions to them. Data on climate, drainage infrastructures and physical planning regulations were collected and extensively analysed. These were combined with evidence from field inspection and discussion with stakeholders, including relevant government departments, university researchers and selected residents. The investigation revealed that, contrary to popular wisdom, climate change or unusually high rainfall is not the primary cause of the flooding problems in Lagos. Rather, the increased urbanisation, lax planning laws in relation to the erection of buildings in flood plains and the lack or inadequacy of storm drainage facilities in the city are to blame. It is argued that a lasting solution to the flooding problem will require the incorporation of sustainable drainage systems within the existing flood management strategy for the city and planning for this must start now.

Effects of floods
Flooding has many impacts. It damages property and endangers the lives of humans and other species. Rapid water runoff causes soil erosion and concomitant sediment deposition elsewhere (such as further downstream or down a coast). The spawning grounds for fish and other wildlife habitats can become polluted or completely destroyed. Some prolonged high floods can delay traffic in areas which lack elevated roadways. Floods can interfere with drainage and economic use of lands, such as interfering with farming. Structural damage can occur in bridge abutments, bank lines, sewer lines, and other structures within floodways. Waterway navigation and hydroelectric power are often impaired. Financial losses due to floods are typically millions of dollars each year, with the worst floods in recent U.S. history having cost billions of dollars.

Control of floods
Some methods of flood control have been practiced since ancient times.[1] These methods include planting vegetation to retain extra water, terracing hillsides to slow flow downhill, and the construction of floodways (man-made channels to divert floodwater).[1] Other techniques include the construction of levees, lakes, dams, reservoirs[1] or retention ponds to hold extra water during times of flooding.

Methods of control
Dams Main article: dam Many dams and their associated reservoirs are designed completely or partially to aid in flood protection and control. Many large dams have flood-control reservations in which the level of a reservoir must be kept below a certain elevation before the onset of the rainy/summer melt season so as to allow a certain amount of space in which floodwaters can fill. The term dry dam refers to a dam that serves purely for flood control without any conservation storage (e.g. Mount Morris Dam, Seven Oaks Dam). Self-closing flood barrier The self-closing flood barrier (SCFB), is a flood defence system to protect people and property from inland waterway floods caused by heavy rainfall, gales or rapid melting snow.[citation needed] The SCFB can be built to protect residential properties and whole communities, as well as industrial or other strategic areas. The barrier system is constantly ready to deploy in a flood situation, it can be installed in any length and uses the rising flood water to deploy. Barrier systems have already been built and installed in The Netherlands, Thailand, Belgium, Italy, Ireland, UK, Vietnam, Australia and the U.S.A. Millions of documents at the National Archives building in Washington DC are protected by two SCFBs.[citation needed] River defences In many countries, rivers are prone to floods and are often carefully managed. Defences such as levees, bunds, reservoirs, and weirs are used to prevent rivers from bursting their banks. When these defences fail, emergency measures such as sandbags or portable inflatable tubes are used. A weir, also known as a lowhead dam, is most often used to create millponds, but on the Humber River in Toronto, a weir was built near Raymore Drive to prevent a recurrence of the flood damage caused by Hurricane Hazel in 1954. Coastal defences Coastal flooding has been addressed in Europe and the Americas with coastal defences, such as sea walls, beach nourishment, and barrier islands.

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Flood control - Wikipedia, the free encyclopedia

Tide gates are used in conjunction with dykes and culverts. They can be placed at the mouth of streams or small rivers, where an estuary begins or where tributary streams, or drainage ditches connect to sloughs. Tide gates close during incoming tides to prevent tidal waters from moving upland, and open during outgoing tides to allow waters to drain out via the culvert and into the estuary side of the dike. The opening and closing of the gates is driven by a difference in water level on either side of the gate.[2]

Flood control by continent
Americas An elaborate system of floodway defenses can be found in the Canadian province of Manitoba. The Red River flows northward from the United States, passing through the city of Winnipeg (where it meets the Assiniboine River) and into Lake Winnipeg. As is the case with all north-flowing rivers in the temperate zone of the Northern Hemisphere, snowmelt in southern sections may cause river levels to rise before northern sections have had a chance to completely thaw. This can lead to devastating flooding, as occurred in Winnipeg during the spring of 1950. To protect the city from future floods, the Manitoba government undertook the construction of a massive system of diversions, dikes, and floodways (including the Red River Floodway and the Portage Diversion). The system kept Winnipeg safe during the 1997 flood which devastated many communities upriver from Winnipeg, including Grand Forks, North Dakota and Ste. Agathe, Manitoba. In the U.S., the New Orleans Metropolitan Area, 35% of which sits below sea level, is protected by hundreds of miles of levees and flood gates. This system failed catastrophically, with numerous breaks, during Hurricane Katrina in the city proper and in eastern sections of the Metro Area, resulting in the inundation of approximately 50% of the Metropolitan area, ranging from a few inches to twenty feet in coastal communities. The Morganza Spillway provides a method of diverting water from the Mississippi river when a river flood threatens New Orleans, Baton Rouge and other major cities on the lower Mississippi. It is the largest of a system of spillways and floodways along the Mississippi. Completed in 1954, the spillway has been opened twice, in 1973 and in 2011. In an act of successful flood prevention, the Federal Government of the United States offered to buy out flood-prone properties in the United States in order to prevent repeated disasters after the 1993 flood across the Midwest. Several communities accepted and the government, in partnership with the state, bought 25,000 properties which they converted into wetlands. These wetlands act as a sponge in storms and in 1995, when the floods returned, the government did not have to expend resources in those areas.[3] Asia In China, flood diversion areas are rural areas that are deliberately flooded in emergencies in order to protect cities.[4] The consequences of deforestation and changing land use on the risk and severity are prone to discussion. In assessing the impacts of Himalayan deforestation on the Ganges-Brahmaputra Lowlands, it was found that forests would not have prevented or significantly reduced flooding in the case of an extreme weather event.[5] However, more general or overview studies agree on the negative impacts deforestation has on flood safety - and the positive effects of wise land use and reforestation.[6][7] Europe London is protected from flooding by a huge mechanical barrier across the River Thames, which is raised when the water level reaches a certain point (see: Thames Barrier). Venice has a similar arrangement, although it is already unable to cope with very high tides. The defenses of both London and Venice will be rendered inadequate if sea levels continue to rise. The largest and most elaborate flood defenses can be found in the Netherlands, where they are referred to as Delta Works with the Oosterschelde dam as its crowning achievement. These works were built in response to the North Sea flood of 1953, in the southwestern part of the Netherlands. The Dutch had already built one of the world's largest dams in the north of the country. The Afsluitdijk closing occurred in 1932.

Flood blocking the road in Jerusalem

The Saint Petersburg Flood Prevention Facility Complex was completed in 2008, in Russia, to protect Saint Petersburg from storm surges. It also has a main traffic function, as it completes a ring road around Saint Petersburg. Eleven dams extend for 25.4 kilometres (15.8 mi) and stand 8 metres (26 ft) above water level.

Flood clean-up safety
Clean-up activities following floods often pose hazards to workers and volunteers involved in the effort. Potential dangers include electrical hazards, carbon monoxide exposure, musculoskeletal hazards, heat or cold stress, motor vehicle-related dangers, fire, drowning, and exposure to hazardous materials.[8] Because flooded disaster sites are unstable, clean-up workers might encounter sharp

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Flood control - Wikipedia, the free encyclopedia

jagged debris, biological hazards in the flood water, exposed electrical lines, blood or other body fluids, and animal and human remains. In planning for and reacting to flood disasters, managers provide workers with hard hats, goggles, heavy work gloves, life jackets, and watertight boots with steel toes and insoles.[9]

Europe is at the forefront of the flood control technology, with low-lying countries such as the Netherlands and Belgium developing techniques that can serve as examples to other countries facing similar problems.[10] After Hurricane Katrina, the US state of Louisiana sent politicians to the Netherlands to take a tour of the complex and highly developed flood control system in place in the Netherlands.[11] With a BBC article quoting experts as saying 70% more people will live in delta cities by 2050, the number of people impacted by a rise in sea level will greatly increase.[12] The Netherlands has one of the best flood control systems in the world and new ways to deal with water are constantly being developed and tested, such as the underground storage of water, storing water in reservoirs in large parking garages or on playgrounds,[12][13] Rotterdam started a project to construct a floating housing development of 120 acres (0.49 km2) to deal with rising sea levels.[14] Several approaches, from high-tech sensors detecting imminent levee failure to movable semi-circular structures closing an entire river, are being developed or used around the world. Regular maintenance of hydraulic structures, however, is another crucial part of flood control.[15]

Benefits of flooding
There are many disruptive effects of flooding on human settlements and economic activities. However, flooding can bring benefits, such as making soil more fertile and providing nutrients in which it is deficient. Periodic flooding was essential to the well-being of ancient communities along the Tigris-Euphrates Rivers, the Nile River, the Indus River, the Ganges and the Yellow River, among others. The viability for hydrologically based renewable sources of energy is higher in flood-prone regions.

See also
Flood barrier Flood wall Flood Control Act of 1934 (in the US) Hydrological Ensemble Prediction Experiment Maeslantkering - Netherlands MOSE project - Venice Northern Stormwater Interceptor, Bristol (in the UK) Thames Barrier - London Tidal barrage U.S. Army Corps of Engineers Weir

1. ^ a b c d e "Flood Control", MSN Encarta, 2008 (see below: Further reading). 2. ^ Guillermo R. Giannico; Jon A. Souder. "The Effects of Tide Gates on Estuarine Habitats and Migratory Fish" ( . 3. ^ Floods, Tornadoes, Hurricanes, Wildfires, Earthquakes... Why We Don't Prepare. Amanda Ripley. Time. August 28, 2006. ( /0,9171,1229102,00.html) 4. ^ [1] ( /07/content_243670.htm) 5. ^ Hamilton, Lawrence S (1987). "What Are the Impacts of Himalayan Deforestation on the Ganges-Brahmaputra Lowlands and Delta? Assumptions and Facts". Mountain Research and Development (Bern: International Mountain Society) 7 (3): 256–263. JSTOR 3673202 ( . 6. ^ Semi, Naginder S (1989). "The Hydrology of Disastrous floods in Asia: An Overview" ( /agosto/PDF/ENG/DOC3893/doc3893-contenido.pdf) . Hydrology and Water Resources Department (London: James & James Science Publishers). /agosto/PDF/ENG/DOC3893/doc3893-contenido.pdf. Retrieved 15 September 2010. 7. ^ Bradshaw CJ, Sodhi NS, Peh SH, Brook BW. (2007). Global evidence that deforestation amplifies flood risk and severity in the developing world. Global Change Biology, 13: 2379-2395. 8. ^ "Storm and Flood Cleanup" ( /topics/flood/) . National Institute for Occupational Safety and Health. Retrieved 23 September 2008. 9. ^ "NIOSH Warns of Hazards of Flood Cleanup Work" ( . National Institute for Occupational Safety and Health. NIOSH Publication No. 94-123. 10. ^ /08/0829_wiredutch.html 11. ^ Goldenberg, Suzanne (5 June 2009). "US urged to abandon ageing flood defences in favour of Dutch system" ( . The Guardian (London). /environment/2009/jun/05/flooding-us-defence. 12. ^ a b "In pictures: Rotterdam strengthens sea defences" ( . BBC News. 27 November 2009. /8362183.stm. 13. ^ /2008%20Leaflet%20Innovative%20water%20storage%20techniques.pdf 14. ^ 15. ^ Broad, William J. (6 September 2005). "In Europe, High-Tech Flood Control, With Nature's Help" ( /2005/09/06/science/06tech.html) . The New York Times.

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Flood control - Wikipedia, the free encyclopedia

Adeloye, A. and Rustum R., 2011. Lagos (Nigeria) flooding and influence of urban planning. Journal of Urban Design and Planning (ICE), Volume 164, Issue 3, June 2011, pages 175 –187, ISSN: 1755-0793, E-ISSN: 1755-0807

Further reading
"Flood Control" ( . MSN Encarta. 2008. Archived from the original ( on 2009-10-31. /query?id=1257024274434364. Retrieved from "" Categories: Flood control

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Why is it important to be prepared for a flood? ›

Flooding can have a harmful effect on your health, home or business. By putting some safeguards and planning in place, you can help reduce the risk of flooding and its impact on you.

What do you do in the event of a flood? ›

Follow these simple steps to stay safe during a flood
  • Check in with other people in your household - if they are not at home make sure they are somewhere safe.
  • Gather essential items together either upstairs or to a high place.
  • Move your family and pets upstairs, or to a high place with a means of escape.

What to do in the event of a flood in the workplace? ›

First Steps
  • Notify your insurance company that the property has been flooded. ...
  • Notify your own family and that of any employees with you. ...
  • Implement your business recovery plan.
  • Notify customers. ...
  • Speak to your insurer. ...
  • Do not return to the property until you are told it is safe to do so.

What are the five things we should do during flood? ›

  • • Ignore rumours, stay calm, don't panic. ...
  • • Don't enter floodwaters. ...
  • • Do not allow children to play in or near flood waters. ...
  • • Raise furniture, appliances on beds and tables. ...
  • • Keep cattle / animals in the shed and ensure their safety. ...
  • • Don't leave the harvested produce in the open field.

How can students prevent floods? ›

Basic education on how to prevent flood situation
  1. Construct barriers. If flood water is entering your area then construct barriers to stop floodwater from entering your home. ...
  2. Try to stay out of floodwater.
8 Aug 2019

What are the 10 steps to disaster preparedness? ›

10 Steps to Disaster Preparedness
  1. Assess your risk – both internally and externally.
  2. Assess your critical business functions.
  3. Prepare your supply chain.
  4. Back-up your data.
  5. Create an emergency management plan.
  6. Create a crisis communications plan.
  7. Assemble emergency supplies.
  8. Plan for an alternate location.

How do you prepare for flood risk? ›

Clear debris from gutters. Make sure that you clear any debris from gutters and downspouts to avoid an accumulation of water. Elevate or move your furniture. When flooding is predicted or imminent, move furniture and valuables to a safe place, such as an attic or the highest floor of your home.

What do you need to prepare for a flood? ›

Put together an emergency kit in case of a flood (or any natural disaster, really), which should include a first aid kit, a torch, radio, drinking water, food that won't perish quickly (such as canned food), and extra batteries.

Do and don'ts during flood? ›

Don't eat any food that has come into contact with flood water. Don't reconnect your power supply until a qualified engineer has checked it. Be alert for gas leaks – do not smoke or use candles, lanterns, or open flames. Never turn on ceiling fixtures if ceiling is wet.

How do you manage an emergency? ›

Prevention, mitigation, preparedness, response and recovery are the five steps of Emergency Management.

What is emergency planning in safety? ›

The main objectives of an emergency plan are:- a. to control and contain the incident/accident and if possible, eliminate it; and b. to minimize the effects of the incident on persons, property and environment.

What are the 6 requirements of an emergency plan? ›

Developing an Emergency Preparedness Plan is crucial, and here are six elements you should include in it.
  • 1) Risk assessment. ...
  • 2) Protective actions for life safety. ...
  • 3) Incident stabilization. ...
  • 4) Predicted weather emergencies. ...
  • 5) Review your insurance and contracts. ...
  • 6) Financial considerations.

How can we prevent floods Class 9? ›

Planting vegetation to retain excess water, terrace slopes to reduce slope flow, and building alluviums (man-made channels to divert water from flooding), construction of dykes, dams, reservoirs or holding tanks to store extra water during flood periods.

How can we control floods PPT? ›

Methods of flood control
  1. Name: Dharmesh G. ...
  2. 1) Dams 2) Diversion canal 3) Self closing flood barrier 4) River defences 5) Coastal defences.
  3.  Many dams and their associated reservoirs are designed completely or partially to aid in flood protection and control. ...
  4. Mount Morris Dam.
  5. Eider Barrage, landward side, open.
12 Oct 2015

How do people manage floods? ›

Flood mitigation dams can reduce downstream flood levels by temporarily storing and later releasing floodwaters. Most dams are used to supply water to the community, but they can, when purpose built, also provide some flood mitigation for events up to their flood storage capacity.

What is flood explain in 100 words? ›

Paragraph on Flood in 100 Words

A flood is a condition when an area is fully or partially submerged in water for a period of time due to man-made or natural causes. The natural reasons behind floods can be heavy and continuous rain for an extended time period.

How can we prevent 10 point disaster? ›

8 Disaster Preparedness Tips [Video]
  1. Communicate where you will be. ...
  2. Know the warning signs and alert signals for your area. ...
  3. Check your emergency survival kit. ...
  4. Collect emergency building materials. ...
  5. Fuel up your vehicles and equipment.

How can we prevent disasters? ›

Awareness, education, preparedness, and prediction and warning systems can reduce the disruptive impacts of a natural disaster on communities. Mitigation measures such as adoption of zoning, land-use practices, and building codes are needed, however, to prevent or reduce actual damage from hazards.

How can we stay safe from natural disasters? ›

Stay inside if you are inside and outside if you are outside.
  1. Move away from buildings, utility wires, sinkholes, and fuel and gas lines. ...
  2. Go to an open area away from trees, telephone poles, and buildings. ...
  3. The area near the outside walls of a building is the most dangerous place to be.

How do floods affect people? ›

The immediate impacts of flooding include loss of human life, damage to property, destruction of crops and loss of livestock. The ongoing emotional impact is substantial with increased emotional stress and physical illness from waterborne diseases.

What is flood very short answer? ›

Overview. Floods are the most frequent type of natural disaster and occur when an overflow of water submerges land that is usually dry. Floods are often caused by heavy rainfall, rapid snowmelt or a storm surge from a tropical cyclone or tsunami in coastal areas.

How high is a flood? ›

Rapidly rising water can reach heights of 30 feet or more. Furthermore, flash flood-producing rains can also trigger catastrophic mud slides. You will not always have a warning that these deadly, sudden floods are coming. Most flood deaths are due to FLASH FLOODS.

How many types of floods are there? ›

There are three types of floods- flash floods, river floods, and coastal floods.

What is flood causes and prevention? ›

A flood happens when water from a river , lake , or ocean overflows onto the land around it . Too much rain or melting snow are the main causes of floods . Sometimes the soil in the ground can make a flood worse. This is because when rain falls, the soil usually soaks it up like a sponge.

What are 6 The main causes of flooding? ›

What Causes Floods?
  • Heavy rainfall resulting from tropical weather disturbances.
  • Deforestation.
  • Improper agricultural practices.
  • Inadequate design of drainage channels and structures.
  • Inadequate maintenance of drainage facilities, blockage by debris brought by flood waters.
  • Construction of settlements in flood plains.

How do people walk through floods? ›

If you have to walk in water, walk where the water is not moving. Use a stick to check the firmness of the ground in front of you. “Turn around, don't drown!” If you come upon a flowing stream where water is above your ankles, stop, turn around and go another way. People underestimate the force and power of water.

Is it safe to stay in a flooded house? ›

The answer determines whether staying in the house or moving out is appropriate. Clear water such as sinks, water heaters, and washing machines isn't threatening. Dirty water such as sewage, gray water, and water from natural disasters are not safe.

How can kids prepare for a flood? ›

BEFORE A FLOOD: Have a disaster plan. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food, can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.

What causes a flood? ›

Flooding typically occurs when prolonged rain falls over several days, when intense rain falls over a short period of time, or when an ice or debris jam causes a river or stream to overflow onto the surrounding area. Flooding can also result from the failure of a water control structure, such as a levee or dam.

What people need after a flood? ›

When cleaning after a flood or damaging storm, you will need general cleaning supplies, other supplies for making minor repairs, and personal items. Cleaning supplies (and suggested quantities for cleaning a home): Air freshener, 8- or 9- ounce can. Bleach, 82 ounces.

How do floods affect your life? ›

Loss of lives and property: Immediate impacts of flooding include loss of human life, damage to property, destruction of crops, loss of livestock, non-functioning of infrastructure facilities and deterioration of health condition owing to waterborne diseases.

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