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FLOOD MANAGEMENT

TECHNIQUESSuraj S. Lawand

Sunny B. Khemani

D. Y. Patil College Of Engineering , Akurdi , Pune-44.

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Let’s Get Started

1) What are floods ? Types , causes , adverse effects of floods.

2) Necessity Of Flood Management.

3) Techniques Of flood management.

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Definition of Flood

Flood is overflow of water beyond its normal limits especially onto what is normally dry land.

1. Hazardous floods

2. Benificial floods

Types of Floods

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Causes of Floods

1) Natural causes of flood-a) Heavy rainfallb) Snowmeltc) Sudden water released) Coastal flood

2) Man-made causes of flood-e) Deforestationf) Poor water managementg) Population pressureh) Catastrophic failure

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Adverse Effects of FloodsLoss of Lives-

July 1931,china – 10,00,000 to 40,00,000.Oct. 1887,china – 9,00,000 to 20,00,000

Loss of Infrastructure

Inundation Of farm land Structural damage to buildings

Interruption in power transmission

Water contamination

Water borne diseases after flood

Communcation problems Environmental impact

7The road is cut due to flood.

8A small area is completely surrounded by flood water.

9Railway track lost support from ground and may require weeks to repair.

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Houses and cars are floating in flood water. This flood is caused by tsunami.

11House completely submerged in flood water.

12Houses on the verge of getting vanished in extreme river flow.

13Recent flood in India at Uttarakhand.

14Struggling to get out of flood.

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This is why flood management is necessary…because nobody wants to get in this situation.

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Techniques of Flood Management

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Construction of Dams

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1) Most effective way of flood control.2) Dam construction is conventional method.3) Water can be stored in a reservoir and can

be released as per requirement.4) Has many uses – controlling water flow,

storing water and electricity production.5) But very costly.

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River Defense – Levees and bund

Bund

Water topples over these bunds and its speed decreases.

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Levees

1) These occur naturally or built parallel to river flow.

2) Levees act as temporary storage for water during overflow of river and stops water from crossing riverbeds.

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Temporary Perimeter Flood Barriers

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1)They are completely removable barriers.2)Stabilized by applying external weights like

sandbags or water in case of tube shape barriers.

3)Can be mounted quickly on flood warning.

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Flood Control Channel

 Los Angeles River flood control channel.

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1)Large open air channels.2)Made of cement concrete entirely.3)Lower than street level.4)Water is drained to proper water body.5)Very effective in larger cities like Los

Angeles.

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Self-closing Flood Barrier

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Cross section of Self-closing barrier

1) Water level is increasing above warning point.

2) Due to water in first container, barrier door floats and starts gaining height.

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3) The door floats to maximum height and retains water behind the door.

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1)Automatically operated2)This is modern method of flood control.3)Very simple operation.4)Can serve as effective barrier for flood

water.5)Does not obstructs when no flooding.

Benefits of self-closing flood barrier

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Tokyo’s Wonder : G-Cans

From 1980 to 1990 typhoons damaged 30,000 homes of Tokyo.

Japan built something to save Tokyo.

It took 17 years and 2 billion dollars.

The aim was simple: To take all the excess rainwater from typhoons and floods away before it can cause any damage.

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1) 22 m below ground.2) The chambers are 180 m long , 80 m wide and 18 m high.

3) The pipeline is 6.9 km long.

4)Made of RCC only.

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These tunnels carry water from streets to the giant reservoirs.

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Water is collected at different points.

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1)Totally underground.2)It reduced impact on building in entire

Tokyo by 80%.3)Data at Kumugaya station is as follows .

This shows efficiency of this system.

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Conclusion

Floods have always been threatening to human beings.

Floods are not completely avoidable. But we can use modern methods and technology to fight against floods and save thousands of lives every year.

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Reference

www.globalfloodds.comwww.nofloods.comwww.noort-innovation.nlwww.photobucket.comwww.bbc.co.ukwww.japangasm.comwww.chicagotribune.comwww.ccrfcd.orgwww.marine-knowledge.comwww.plasticpiling.co.ukEmergency flood fighting techniques -Department ofWater ResourcesDivision of Flood ManagementFlood Operations BranchAugust 2012

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