Floods are the most common and widespread of all natural disasters. India is one of the highly flood prone countries in the world. Around 40 million hectares of land in India is prone to floods as per National Flood Commission report. Floods cause damage to houses, industries, public utilities and property resulting in huge economic losses, apart from loss of lives. Though it is not possible to control the flood disaster totally, by adopting suitable structural and non-structural measures the flood damages can be minimised. For planning any flood management measure latest, reliable, accurate and timely information is required. In this context satellite remote sensing plays an important role.
Rescue & Evacuation
Evacuation is a pre-emptive move to protect life and property, where as rescue is a post-disaster phenomenon of helping people to move from areas that have been hit by disaster to a safer place. However, the situation of evacuation and rescue comes along with numerous unanswered queries in mind. Very often, due to lack of information or in haste, living during evacuation and rescue becomes difficult and painful. However, during such the situations, following precautionary norms should be kept in mind.
Preparing for a Flood
Here are some basic steps to take to prepare for the flood:
- Contact the local geologist or town planning department or meteorology department to find out if your home is located in a flash-flood-prone area or landslide-prone area.
- Learn about your community's emergency plans, warning signals, evacuation routes, and locations of emergency shelters.
- Plan and practice a flood evacuation route with your family. Ask an out-of-state relative or friend to be the "family contact" in case your family is separated during a flood. Make sure everyone in your family knows the name, address, and phone number of this contact person.
- Post emergency phone numbers at every phone.
- Inform local authorities about any special needs, i.e., elderly or bedridden people, or anyone with a disability.
- Identify potential home hazards and know how to secure or protect them before the flood strikes. Be prepared to turn off electrical power when there is standing water, fallen power lines etc. Turn off gas and water supplies before you evacuate. Secure structurally unstable building materials.
- Buy a fire extinguisher and make sure your family knows where it is and how to use it.
- Buy and install sump pumps with back-up power.
- Have a licensed electrician to raise electric components (switches, sockets, circuit breakers and wiring) at least 12" above your home's projected flood elevation.
- For drains, toilets, and other sewer connections, install backflow valves or plugs to prevent floodwaters from entering.
- Anchor fuel tanks which can contaminate your basement if torn free. An unanchored tank outside can be swept downstream and damage other houses.
If you are under a flood watch or warning:
- Gather the emergency supplies you previously stocked in your home and stay tuned to local radio or television station for updates.
- Turn off all utilities at the main power switch and close the main gas valve if evacuation appears necessary.
- Have your immunization records handy or be aware of your last tetanus shot, in case you should receive a puncture wound or a wound becomes contaminated during or after the flood.
- Fill bathtubs, sinks and plastic soda bottles with clean water. Sanitize the sinks and tubs first by using bleach. Rinse and fill with clean water.
- Bring outdoor possessions, such as lawn furniture, grills and trash cans inside or tie them down securely.
Emergency Supplies You Will Need
You should stock your home with supplies that may be needed during the emergency period. At a minimum, these supplies should include:
- Several clean containers for water, large enough for a 3-5 day supply of water (about five gallons for each person).
- A 3-5 day supply of non-perishable food and a non-electric can opener.
- A first aid kit and manual and prescription medicines and special medical needs.
- A battery-powered radio, flashlights, and extra batteries.
- Sleeping bags or extra blankets.
- Water-purifying supplies, such as chlorine or iodine tablets or unscented, ordinary household chlorine bleach.
- Baby food and/or prepared formula, diapers, and other baby supplies.
- Disposable cleaning cloths, such as "baby wipes" for the whole family to use in case bathing facilities are not available.
- Personal hygiene supplies, such as soap, toothpaste, sanitary napkins, etc.
- An emergency kit for your car with food, flares, booster cables, maps, tools, a first aid kit, fire extinguisher, sleeping bags, etc.
- Rubber boots, sturdy shoes, and waterproof gloves.
- Insect repellent containing DEET, screens, or long-sleeved and long-legged clothing for protection from mosquitoes which may gather in pooled water remaining after the flood.
Preparing to Evacuate
Expect the need to evacuate and prepare for it. When a flood watch is issued, you should:
- Fill your vehicle's gas tank and make sure the emergency kit for your car is ready.
- If no vehicle is available, make arrangements with friends or family for transportation.
- Fill your clean water containers.
- Review your emergency plans and supplies, checking to see if any items are missing.
- Tune in the radio or television for weather updates.
- Listen for disaster sirens and warning signals.
- Put livestock and family pets in a safe area. Due to food and sanitation requirements, emergency shelters cannot accept animals.
- Adjust the thermostat on refrigerators and freezers to the coolest possible temperature.
If You Are Ordered to Evacuate
You should never ignore an evacuation order. Authorities will direct you to leave if you are in a low-lying area, or within the greatest potential path of the rising waters. If a flood warning is issued for your area or you are directed by authorities to evacuate the area, follow the below mentioned checklists:
- Take only essential items with you.
- If you have time, turn off the gas, electricity, and water.
- Disconnect appliances to prevent electrical shock when power is restored.
- Follow the designated evacuation routes and expect heavy traffic.
- Do not attempt to drive or walk across creeks or flooded roads.
If You Are Ordered NOT to Evacuate
To get through the storm in the safest possible manner:
- Monitor the radio or television for weather updates.
- Prepare to evacuate to a shelter or to a neighbour's home if your home is damaged, or if you are instructed to do so by emergency personnel
Safety and Security
Any natural calamities espouse itself with serious devastation to transportation, communication chaneel, supply of electricity etc. Hence, in the immediate aftermath of any calamity, the surrounding environment becomes dangerous and unsafe due to it's exposure to toxic and harmful objects. This becomes more important for children as they are usually overlooked by the parents during the calamity or in the immediate aftermath of it. The following safety and security guidelines can be kept in mind.
MANAGEMENT TECHNOLOGIES FOR FLOOD AFFECTED FIELD
Management Technology for submerged paddy / flooded paddy at harvest
Unforeseen situation may arise during any stage of paddy cultivation. If late incessant rains are received, standing paddy crop may be submerged even for days together and it may be even at harvest stage. Technologies to manage this situation are:
- As a first step drainage should be aided and all possible means are to be taken up.
- Immediately after the standing water column recedes, combine harvesters can be used for rapid harvesting of the crop. Special harvesters are available to work in a mire situation.
- The grain at this situation may be excessively wet. If drying is difficult for few days, the harvested grain may be mixed with common salt and the produce may be sun dried at the earliest opportunity.
Flood affected paddy field
Mitigation of Water logging Stress
- Providing adequate drainage for draining excessive stagnating water around the root system.
- Spray of growth retardant of 500 ppm cycocel for arresting apical dominance and thereby promoting growth of laterals
- Foliar spray of 2% DAP + 1% KCl (MOP)
- Nipping terminal buds for arresting apical dominance and thus promoting growth sympodial branches (as in cotton) for increasing productivity
- Spray of 40 ppm NAA for controlling excessive pre-mature fall of flowering/buds/young developing fruits and pods
- Spray of 0.5 ppm brassinolide for increasing photosynthetic activity
- Foliar spray of 100 ppm salicylic acid for increasing stem reserve utilization under high moisture stress
- Foliar spray of 0.3 % Boric acid + 0.5 % ZnSO4 + 0.5 % FeSO4 + 1.0 % urea during critical stages of the stress.
The adverse effects of waterlogging can be reduced to some extent by supplying nitrogenous fertilizers. The best method of avoiding waterlogging is by providing suitable drainage.
Agricultural drainage is the provision of a suitable system for the removal of excessive irrigation or rain water from the land surface so as to provide suitable soil conditions for better plant growth.
Advantages of agricultural drainage
- Provision of drainage facilitates early sowing of the crop.
- Agricultural land can be used for a long time without any deterioration due to damaged soil structure and salt concentration.
- Drainage lowers underground water table so as to facilitate increased root zone depth. Drainage improves soil aeration and increases soil temperature
Drainage for agricultural land is provided by surface and subsurface drainage.
- Surface drainage is the simplest and the most common method.
- Drainage is achieved by digging open drains at suitable intervals and depth.
- Irrigation channels also serve as drainage channels.
Advantages of surface drainage
- Provision of surface drainage is cheap.
- The defects in the open drainage can be seen easily and rectified.
- It requires less available fall or grade to have an adequate outlet.
Disadvantages in surface drainage system
- Considerable amount of land is wasted for open drains.
- These drains cause hindrance to field preparation and intercultivation.
- The drains get silted and periodical desilting is necessary.
- Weed growth in the drains is heavy and this has to be removed.
- Open drains are damaged by rodents and farm animals.
Different methods of surface drainage
Random Field Ditch Method
Standing water may be present in the field at several places distributed randomly. These depressions or micro ponds are connected by mean of shallow channels or ditches and these are led into an outlet.
The elevated area is cut off and excess soil is spread over low areas so that the surface is even with uniform slope. Excess surface run off is collected and conveyed into the field ditches provided at the lower end of the field.
Small furrows are formed at known intervals parallel to the slope for draining out water. These furrows are known as dead furrows and land between these furrows is known as beds. Small ridges or bunds are made at the centre of the bed with gradual slope to drain water into the dead furrows.
Parallel Field Ditch system
It is almost similar to bedding system except for deep drains and uneven interval between drains.
Broad Bed and Furrow Method
The field is laid out with beds and wide furrows across the slope. About 0.5 per cent slope is provided for the furrows for free drainage. Crops are sown on the beds and furrows help in drainage of water when there is excess rain.