Managing flood defences and risks for a region is not a simple matter of stocking up on sandbags. Floods come quickly and create long-term damage that can leave neighborhoods and towns practically destroyed for months afterwards. As a result, flood defenses are critical to avoid such disasters proactively.
Levees
The use of earth has long been a traditional approach to managing flood risks which has its pros and cons. While levees involving large mounds of dirt ringing in water flows to channel them elsewhere can last for decades, when they break the results are catastrophic.
Levee systems have an inherent risk in that they take wide flows of water and channel them into tight canals. This increases the level and pressure of water flowing through. As a result, when there is a leak, the water will flow out at high speed and decimate the immediate surrounding area.
Causeways
Levee systems that are expected to have heavier flow than they can manage are usually designed with causeways where gates can be opened to let water be diverted. This typically occurs onto farmland that is left dormant during the winter time. The release takes the pressure off of connected levees and reduces the water pressure on wide plain areas. It also makes a good opportunity for growing water crops such as rice.
Building Up
In areas where water cannot be easily diverted, structure design takes into account regular flood and uses foundation systems that lift building high up off the ground. This allows occasional flooding to occur without causing any damage to the building above. While the inconvenience of water may make it a bit difficult to traffic in the area, the building and its contents are kept safe and dry until the water level recedes. Many river towns had homes built upward two or three stories because flooding was common before levee systems were introduced.
Dam Management
A number of towns live down-river from dams and water-blocking infrastructure. When the wet season hits, these storage facilities typically let loose their current reserves to make room for more water coming down from mountains and watershed regions. This room allows the dam system to capture the surge and manage it before it reaches the towns below. Doing so creates a control on the water flow, making it predictable rather than an uncontrolled push that tops levees and river banks. At the same time, the controlled flow can also be harnessed to generate energy through hydroelectric systems, adding power to the electricity grid for the region.
Conclusion
Flood protection systems are frequently a mixed bag, depending on the region and funding available for construction. Regions try their best to have reliable systems, but too often these protections must compete with other municipal projects and programs. It's in this respect that flood defences typically fail, lacking maintenance regularly required.
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For 15 Years Kevin Williams has restored flood damaged properties ranging in size from domestic dwellings to commercial factories.In 2010 He set up Floodsense offering his expertise in Flood Prevention Techniques, Systems and Services.For free E-book, further info on Flood Defences, and professional advice on flood prevention from a leading UK flood protection company, visit http://www.floodsense.co.uk
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