Plan today for tomorrow's flood

Feb 15, 2013
by WLJ

Though drought has been the big weather story of the past year, some areas are getting more precipitation than usual. Floodwaters pose risks to both agricultural retailers and their communities so it is important to be prepared. By implementing some practical preventative measures, the severity of any flood you might experience can be lessened.

There are many possible flood scenarios. For instance, too much debris (such as leaves, tree limbs and trash) can clog street drains or ditches that cause flooding after a heavy rain. In such cases, water collects on paved surfaces instead of being absorbed by soil, filling water retention ponds, or going downstream.

Floods also happen when a river’s or creek’s natural bank or levee cannot contain the water within its channel. Such floods often recede slowly, because the floodwaters cannot drain back into streams, creeks or ditches until the water level downstream drops to pre-flood levels. In this type of flood, waters tend to rise slowly and predictably, so emergency responders often have more time to warn the public.

Flash floods develop quickly and without much warning. For instance, an area might receive 8 to 10 inches of rain in an afternoon, and quickly saturate the soil. Once this happens, water will start to run off, filling low-lying areas first. As the water flows downhill, it eventually passes through, or concentrates on, just a few acres of ground, causing deep water in those areas. The deluge also can overwhelm the ability of creeks and streams to carry the water away. The water accumulates, and the ditches or creeks overflow their banks.

Walls of water can roll across farms and towns and wreak havoc in their wakes. To make matters worse, floods can weaken levees and cause them to fail, releasing billions of gallons of water into already flooded areas. Broken levees often produce historic 100-year floods where the water is so deep that only the rooftops of buildings are seen. Flash flooding from levee breaks happens so quickly that the only recourse may be immediate evacuation.

Another form of flooding that plagues buildings is reverse flow flooding. This happens to buildings tied into public sewer systems. When heavy water loads on and around these public systems are too great, water pushes into sewers and works its way back into lowlying outlets in basements or into buildings with low grades. This type of flooding is often nasty because it can include sewage and all other types of foreign materials.

It is important to remember floods can happen even when it doesn’t rain in your area and can occur anywhere—even in deserts— given the right circumstances.

Stay safe

In flash floods or when waters are rapidly rising, the best and only plan may be to evacuate people safely. Local emergency managers and planners must be involved in these types of plans, especially if evacuation routes go through floodprone areas and jeopardize evacuees. Work with local emergency managers to develop guidelines to determine when it’s time to move people out.

Develop plans for rescuing workers who may be trapped in the facility. People often become trapped in their homes or other buildings because they keep going to higher floors to avoid floodwaters. Make sure employees know how to stay safe. Provide communication equipment that will work when power is out, so employees can call for help if they become trapped.

Don’t allow employees to risk their lives rushing to the rescue. Constantly remind employees that safety is first. During flash floods, once-gentle creeks can sweep people away. The force of water is very powerful and can move tons of soil.

Don’t ever try to drive through floodwaters. Only a foot of water can float most vehicles and two feet of moving water can sweep a truck off the road.

Staying safe also involves being properly prepared. Avoid the situation that one policeman found himself in:

“We tried to rescue a person who was swept into a fast-flowing, flooded creek. We formed a human rescue line by grabbing hands, but we were still a few feet too short to reach him as he went by. Who would have thought, in our flat little town, that a flotation device on a rope would have saved a life?” Other preparatory activities include having not only a plan, but knowledge of who should be where, inventories of sensitive items like chemicals and medicines, and things like reserve animal feed at any given time.

In the potential stress and chaos of an impending flood situation, knowing where and how much/many of these things exist and what their priorities are will go a long way to being safe. In many cases, not only you or your staff can be affected by problems, especially with agricultural chemicals, but your entire community as well.

While floods make immediate headlines, the real work comes after, when communities turn their attention to cleaning up. In many ways, the risks to people during the recovery may be greater than the flood itself. Take extreme care when reentering areas that were flooded.

One danger after any flood is the drive back to your facility. Never return to your facility until authorities give approval. Flowing water may have washed out parts of roads or weakened them.

Even if the likelihood of a flood seems low, investing some time and effort—even if only mental—into planning and preparation will pay in saved stress and loss of life or limb should one occur. — WLJ