Flood mitigation
By:Mudassar Rehan(B.ARCH/1003/08)Alain Ekka (B.ARCH/1011/08)Md.Azizullah(B.ARCH/1033/08)
Flood mitigation involves managing the effects of flooding, such as redirecting flood run-off, rather than trying to prevent it altogether. It is management of people, through measures such as evacuation and dry/wet proofing properties.
Floods are water covering previously dry area.A flood is a very large amount of water that has overflowed from a source such as a river, lake, and ocean. They can also have overflowed a broken pipe onto a previously dry area. The damages after a flood is harsh because everything or parts of things will be under water and the effects of a flood can kill many people.
Flooding occurs in a wide variety of settings:
Riverine flooding
Coastal zone flooding with wave actionHigh, saturated ground water
Back up flooding from rivers, creeks, drainage basins
Dams and levees breaking
Clogged culverts causing water back upBack flow from sewer lines
Downhill sheet flow after a heavy rain or snow melt
Roof drainage into the house
Flooding conditions can be:
Shallow to deep water
Short warning time
High or low flow velocities
Long or short duration
High rates of rise and fall
Wave action
Debris potential
Hazardous materials in the water
Low-point water entry in the house
Let the Flood Plain be a Flood Plain
Nutrient rich soils settle out in the flood plain not in the stream
The easiest way to mitigate flood damage is to let the flood plain act as a flood plain. When there is more water in the stream than it can hold, the water spreads out in the flood plain. As the water recedes, the water in the flood plain works it’s way slowly back to the river. This is the natural function of flood plains. If we try to force the river to stay within the banks during a flood, the stream cuts down and bank erosion gets worse.
Allow the flood plain to be a flood plain and do not build houses, businesses or industries in the flood plain we end up with less mess, less flood damage and less water pollution.
Less MessLess Damage
Less Water Pollution
Flood Mitigation in the Watershed
Reduce:•Flood Frequency•Intensity
•Increase Retention•Increase Infiltration
Reduce Pollution
Retain Water in Watershed
Pond
Sediment settles out
Storm Water Retention Basin
Sunlight kills pathogens
Retain Water in Watershed
Sediment settles out
Sunlight kills pathogens
Plants capture nutrients
Let The Water Soak In
Terraces
Keeps sediment and phosphorus in the field
Cover crops
Nitrogen held in plants
Permanent grass
Keeps sediment and phosphorus in the field
Rain Gardens
Bio swales
Water evaporated through plants
Nitrogen held in plants
Pervious Pavement
Less pollution washes off pavement
Green Roofs
Water evaporated through plants
Conclusion
As we work to:
Reduce flood frequency & intensity
Reduce damages from flooding
Hold more rain water in the watershed
Let the flood plain be a flood plain
Improve water quality
Thank you!!!