COMMUNITY FLOOD REDUCTION MEASURES

Copied from an article with the title: BASIC INFORMATION FOR COMMUNITY FLOOD PREPAREDNESS, written by mr. ir. Krisno Nimpuno, on behalf of DERC, Disaster and Emergency Reference Center, date October 1999

Local communities in delta areas around the world apply, often in the absence of government provided protection, have to manage flood reduction measures. The more frequent and severe floods visit the area the greater range of defense options is developed.
In areas with substantial population movements however collective memories weaken and with it the possibilities of community action. It has also been found that some ideas from elsewhere may help in the development of community based flood reduction.

High flood refuges, terps
In many delta areas communities identify or built flood refuges. These can be natural or purpose built hills, that are then improved with emergency facilities. Elevated flood shelters within short distances from the housing areas are essential in vulnerable, unprotected flood plain areas. The pre-historic Dutch terps were permanent houses on man made hills that protected the wealthy from the misery of floods.

In many coastal and river areas around the world houses on stilts have been developed and applied for this purpose. As mentioned above houses can be built for this reason with several floors, whereby the ground floor is used for less vulnerable activities.

Micro Poldering
Dikes around vulnerable housing areas subject to frequent but low level floods are an effective way of protection. Polders need in addition to the dikes also a drainage system and this can be arranged by wind or engine powered pumps. In the city of Bangkok some well off neighborhoods protect themselves in this way.

High ground agriculture fields
In flood prone rural peasant can reduce economic risks by using high grounds for growing crops that will survive floods. In some cases communal plots are developed as a collective mitigation measure.

High silos
Grain silos ranging from family silos to large communal silos are excellent facilities to reduce flood damages. It allows the community to evacuate a settlement in the knowledge that after the water recedes life speedily can return to normality.

Transparent raw water distillation tents
Safe drinking water is of the greatest importance in flooded areas. Much of the damaging impacts in the aftermath of floods is related to the use of polluted water. Transparent plastic tents over polluted water pools can yield enough distilled water for drinking purposes.

Rafts
In very vulnerable communities the availability of boats or rafts can make the difference between life and death. Simple wooden rafts or inflated car tubes can increase survival chances considerably.

Flood Proofinf of Houses

One way to protect a house from shallow flooding is the built a small dike around your house, another is to add a waterproof barrier to the exterior walls and seal all openings, including doors, to prevent the entry of water. The barrier can consist of a layer of brick backed by a waterproof membrane. Before the barrier is applied, the siding is removed and replaced with exterior grade plywood sheathing. If necessary, the existing foundation footing is extended to support the brick. Also, because the wall will be exposed to flood water, changes are made to the interior walls as well so that they will resist moisture damage. In the area below the flood level, standard batt insulation is replaced with washable closed-cell foam insulation, and any wood blocking added inside the wall cavity is made of exterior grade lumber.

Adding a waterproof barrier is appropriate in areas where the flood depth is less than 2 feet. When flood depths exceed 2 feet, the pressure on waterproofed walls increases greatly, usually beyond the strength of the walls. If your house is flooded by groundwater entering through the floor, this method will not be effective.

Raising Electrical System Components
Electrical system components, including service panels (fuse and circuit breaker boxes), meters, switches, and outlets, are easily damaged by flood water. If they are inundated for even short periods, they will probably have to be replaced. Another serious problem is the potential for fires caused by short circuits in flooded systems.
Raising electrical system components helps you avoid those problems. Also, having an undamaged, operating electrical system after a flood will help you clean up, make repairs, and return to your home with fewer delays.
All components of the electrical system, including the wiring, should be raised at least one foot above the expected flood level.
In flood prone areas one needs a modern circuit breaker system and higher-amperage service.

Raise or Flood proof HVAC Equipment

US mitigation participation

• Elevation regulations
• Zoning
• Flood proofing
• Floodway regulations
• Septic tank regulations
• Sedimentation and erosion
• Wetland protection
• Critical area designation
• Density control
• Sand dune protection

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  Water Emergency Control: COMMUNITY FLOOD REDUCTION MEASURES