Is There a River in Your Town?
Jim Segerstrom, one of the USs top swiftwater rescue instructors, was recently teaching a course in Wales for Rescue 3 UK. After the course, he recalls, we were sitting around the pub in Llangollyn, having a pint of bitter, when a paramedic for the Welsh Health Service commented that my emphasis on flood rescue preparedness was ill‑placed. It doesn't flood in the UK like it does in the U.S., he said. You have developed dams and agriculture to the point that the major rivers in the U.S. contribute to the flooding. We don't have those kinds of problems here. Our Water Authority has good control of the rivers.
Segerstrom recited the latest intelligence from weather authorities around the world. The environment is warming. The drought/flood cycle is increasing in severity. Floods are already the #1 weather‑related killer worldwide. Ill bet you 50 quid that before I come back next year, the UK has major flood problems, he said.
The next morning, Segerstrom noted, a disaster map was published as the result of a government study conducted at Oxford University showing a nationwide rise in the sea level by 2006 of about a meter. The day after that the Shrewsbury newspaper showed several firefighters in a boat wearing fire helmets trying to check out a car in the middle of a flooded river. The day after that, it started to rain. Within the week, the BBC was reporting the worst flooding in England in 150 years. Eleven people, including two very skilled boaters, lost their lives in extensive flooding that inundated large areas of southwest England and southern Wales. I returned home to find an e‑mail from UK swiftwater rescue instructor and author Franco Ferrero titled: You won your bet big time?
Not to be outdone, the Yanks were showing that they, too, were unprepared. In Kansas City, 12 people drowned in a single day of flash flooding in October, seven of them in one horrific incident in which three cars were swept off a bridge into a flooded creek. Yet there is undeniably a sort of collective blindness about the need for flood and swiftwater rescue. About the same time as Jim was in Wales, I was talking to authorities in New Zealand who said much the same thing: We dont have those kinds of problems here.
Noahs neighbors probably had similar opinions about that crazy guy who was building a boat in his back yard.
The plain fact is, if you put enough water into just about anywhere, you will get a flood. If there is any gradient, however slight, the water will move and you will have swiftwater. Now you have several thousand tons of water that isnt just sitting there. Its moving, pressing against anything in it with a force you will find hard to imagine if you havent felt it before. If the speed of the water doubles, the force quadruples. Because its all moving, things happen fast, and the incident, unlike a structure fire, moves too. All this can be dealt withif you have the right equipment and training.
We often think of floods as something that happens in rivers. But what happens when the main street of your town becomes a river? If we have a lot of water, and it moves, then we have an urban river. Ah, but wont the storm water system handle it?
Not really. Most urban storm water systems are not equipped to handle major storm events. Even cities like Los Angeles, which has the largest flood control system in the world, cant deal with anything larger than a 25-year event. As the cities sprawl and urban development increases, concrete and asphalt replace fields and woodlands, making flash flooding problems worse. Flood control projects in one area often simply move the problem into someone elses neighborhood.
So now imagine that there is a river flowing along at, say, 9 km/hr down the main street of your city. A persons body caught in that current will have a force of 1.3kN(302 lb.) pushing against it. Cars are starting to float by, some with people in them. It doesnt take much water to get a car floatinghalf a meter is plenty for most models.
How are you going to rescue those people? Do your people have enough life jackets, not only for themselves but for anyone they might rescue? Have police and fire agencies had at least awareness-level swiftwater training so that they can at least protect themselves?
A big storm will quickly fill up a citys storm water system. Excess water will go into the streets. With water filling the storm water system, water will begin flowing out it, blowing off the manhole covers. In extreme cases youll actually see a geyser effect with water spewing out into the street. Other times all youll see will be a hump of water in a flooded street. This creates a very hazardous situation. Eventually the flood will peak and the water begins going back into the storm sewers, pulling anything in the current with it. People, even cars, can be slurped down into the drains this way, with a very poor chance of survival or rescue.
Flash flood events happen quickly. In the recent Kansas City incident, for instance, the rain began about 7pm. Flooding began around 8pm, and most of the fatalities occurred between then and midnight. By 1am the water had receded enough to begin searching for the victims. As the incident unfolds, dispatch is overwhelmed by the sheer volume of calls, and available rescue resources quickly run out. Time is as much an enemy as the water. Rescues will be done or not by the people on the spot, since there is little time to bring in outside resourcesan excellent argument for training as many people as possible.
How can this be avoided? A good preplan really helps. Where are the low bridges, and houses built on the flood plain? Where are street crossings that usually flood? Are there small creeks and watercourses that can flood? How much rainfall does it take? How can rescue units deploy if their normal routes are flooded? Have you made contact with the weather services, so that you have some warning before the flooding starts? If you have just a few hours warning you can pre-dispatch units to known trouble spots.
The easiest rescue is one you dont have to make. Since you know which streets are going to flood, you can block them off. Of course, the barricades will have to be manned, or people will simply ignore them. The single most common cause of swiftwater deaths (at least in the developed world) are cars being swept off roads by flood waters. It also helps to have a public education program so that drivers know why they shouldnt drive through moving water.
A flood is by definition an interagency event. Have you coordinated with other agencies in your jurisdiction like police and EMS? Are there other agencies outside your area with swiftwater that can be activated for mutual aid? How long will it take for them to deploy?
Finally, dont forget to decontaminate your people after the event, as well as any victims you recover from flood waters. Especially in urban areas, flood waters pick up a witches brew of toxic materials, petrochemicals, pesticides, and other noxious chemicals. Take a sample for the lab and thoroughly decontaminate all personnel immediately after the event.
Floods are sudden and deadly. They can happen anywhere and give no quarter. Time works against you. Only with adequate prior preparation, training and preplanning can you hope to survive and rescue others in its path.
This article originally appeared in Fire & Rescue Magazine (UK)
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