Long Island was battered with record rainfall last week. It caused both physical and emotional damage to thousands of residents and businesses. If you were one, I'm sorry for your losses and can only now offer advice to prevent it from happening in the future.
My college degree is in geology, and two of the areas that fascinated me were geomorphology and hydrogeology. Geomorph, as we called it back then, is the study of the shape of the Earth. Hydro, as it was known by undergrads, is the study of groundwater. If you were a victim of flooding, both of these subjects should be of keen interest.
I've also been a licensed plumber for more than 30 years and know a few things about buried pipelines, both in homes and storm sewers in city streets. In some older communities, it's common for the storm sewers to be combined with the sanitary sewers.
Historic storms in places that have these combined sewers can cause raw sewage to back up into the basements of homes when the sewer lines become overloaded with rainwater that pressurizes the pipes.
The first thing you should realize is that normal soil can hold only a given amount of water. There's only so much air space in topsoil. When the topsoil fills with water, any remaining rain begins to travel over the surface of the land. If your home is in a low-lying area, a catastrophic storm can create a mass of water that flows like a wide river as the excess rain makes its way to the ocean.
Water can overwhelm
Storm sewers are not designed to handle historic amounts of rain. To do so would be far too costly. If your municipality has combined sewers, realize that your basement can fill with murky polluted water in an hour or less as water shoots up through floor drains or bubbles out of basement toilets and sinks.
Anything in that space will be ruined. Water can rise so fast that you won't have time to carry valuable things to the first floor. What's more, the water can become electrified if the water rises and floods wall outlets. It then becomes dangerous to be in the rising basement water, trying to carry things to the first floor.
Water flowing through your yard also can rise up against your home and burst basement windows. I once saw a basement fill with water in less than two minutes from a flood like this. It was terrifying.
The bottom line is that you can't stop the water if a huge storm strikes. I don't care how many sump pumps you install. I don't care if your gutters are clean. I don't care if you slope the water away from your foundation.
Have a plan
To minimize damage, you need to have a pre-action plan that includes storing valuable tools, property or keepsakes above any level that might be flooded. With modern weather forecasting, you often can know that bad weather is coming and have time to move objects in your home to a safe spot. But the forecasters and sophisticated prediction software simply can't outsmart Mother Nature and a catastrophic storm can arrive with little notice, sometimes in the middle of the night, while you sleep.
To be completely safe, consider storing your most valuable things in a secure garage or shed. Be sure the items are on shelves and not on the floor. It's a common-sense thing, but, all too often, people just put things on the floor of basements, garages and sheds.
Sturdy shelving is easy to build. Or, you can buy metal shelving units that assemble with no tools. Store valuable items in waterproof plastic containers that have secure lids that will allow the bins to float if the water rises above a level you feel is safe. Large, 10-gallon containers are inexpensive and can offer significant protection.
While the photos and videos of the flooding are still fresh in your mind, look at them again. Note the areas that were hardest hit by the flooding. If where you live has the same topography and didn't get as much rain, the heavy rain belt may affect you next time. Don't assume you'll be dry and safe in the next huge storm.
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