methods of flood control

BVM Engineering college, V.V.Nagar 1

GUJARAT TECHNOLOGICAL UNIVERSITY

BIRLA VISHVAKARMA MAHAVIDYALAYASubject :- Hydrology And Water Resources Engineering

Year : 3rd (5th sem-Civil)

Methods of flood controlCompiled by:- Jora Hitesh .H En no:- 140073106009

Guided by : Prof. Reshma Shah

Prof. Pitroda Sir


Causes of flooding• Monsoon rain• Urbanization increases surface run-off• Dam collapse• Tsunami caused by underwater earthquake• Snow melt• Global warming• Deforestation


To control flooding…..1. Control the water level dams check dams2. Build barriers(Levees) embankments flood walls3. Alter the river’s channel Straighten it Widen and deepen it4. Control land use around the river (land use

zoning)5. Floodways


1. Control the water level


Reservoirs (dams)

• Reservoirs are one of the most direct methods of flood control through storing surface runoff; thus, attenuating flood waves and storing flood water to be redistributed without exceed in downstream flood conditions.

For flood control, it is ideal to maintain the reservoir at the lowest level possible for storage. On the other hand, keeping the reservoir at a high level provides the ability to maintain low flows and hydropower production in droughts.


2.Build barriers(levees)


Levees Levees are one of the oldest forms of river flood

control used to protect people and their property from damaging flood waters.

They consist of earthen embankments built between the river and the area to be protected.

Levees restrict the flood water’s flow to the river side of the levee. This will increase the stage in the river.

Levees should be built well outside the meande width of river’s prone to lateral migration.


LeveesThe elevation of the levee crest is determined

through careful consideration of many factors: Cost risk analysis of the cost to build the larger levee

versus the risk of damage brought on by a larger flood.

Political, social, military, and environmental reasons will all play a part in determining a levee’s design height.

The cost to double the size of a levee is most often correlated to the square of the material needed. This means the cost can be quite high and often prohibit increased levee design elevations.


Freeboard should be taken into account when sizing alevee: 2 ft. for agricultural levees 3 ft. for urban levees

The Mississippi River levee system represents one of the largest such systems found anywhere in the world. They comprise over 3,500 miles (5,600 km) of levees extending some 1,000 miles (1,600 km) along the Mississippi. They average 24 feet (7 m) in height; some Mississippi levees are as much as 50 feet (15 m) high.


3. Alter the river’s channel


4. Control land use


FloodwaysAs defined in River Mechanics, floodways are

dedicated pathways to divert floodwaters into a topographical depression near the river or into another large

Entrance is controlled by hydraulic structures near the floodplain to capture overbank floodwaters.

Sedimentation and scour must be considered in floodway operation and design given the high sediment concentration often found in floodwaters.

It is important to periodically operate these facilities to ensure proper operation during a flood event.


Flood plain zoning


THANKS…!

References-Julien, P. Y. (2002). River Mechanics, Cambridge University Press, UK.-Roberson, J.A., Cassidy, J.J., Chaudhry, M.H. (1998). Hydraulic Engineering, 2nd Edition,Wiley Press, USA. US Army Corps of Engineers. (2010). After Action Report: May 2010 Flood EventCumberland River Basin.<http://www.lrn.usace.army.mil/LRN_pdf/AAR_May_2010_Flood_Cumberland_Draft_V7_21.pdf>