Flood Barriers: alternatives to sandbags

Bigwig - July 23, 2021

With more and more flooding situations happening, and having grown up in a costal area, I’ve been thinking about alternatives to sandbags.  They don’t seem very practical, as you have to have access to a lot of sand or dirt, they are a lot of work to fill, and they are heavy.

One option I found was water-activated flood barriers.  You lay them out and the flood waters activate the material inside and soak up the water to create a barrier.  They are relatively compact, lightweight, can be ready to go in minutes, are stackable, and do not need to be pre-filled.  The downside is they take months to dry out, but I’d rather have that problem versus water damage.  An example is at https://www.amazon.com/dp/B0085S2DEU.  I was able to buy some in 2020 at half priced.

You could also go commando like this guy did.  He saved his home from  over $100,000 in repairs.  Reminds me of someone else long ago who did something a little different before a flood. https://www.wideopencountry.com/houston-man-uses-massive-inflatable-dam-save-house/

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Good morning Bigwig,

The water activated sand bag substitute product is ideal and cost-effective.

Don’t believe they work with seawater and brackish water.

Just read the link.  That Houston guy is someone I’d want in my small group. He’s definitely into “management by objectives” !  Had a good time reading the link.

 

Hi BigWig

For a while I lived in a harbour town that with the right combination of tide and weather conditions would flood.  This wasn’t ‘if it happens’ but ‘when it happens’! Those who lived right on the harbour side all had slots in the doorway for a weatherboard.  The first sign of trouble and people would start putting their boards in! Sandbags take time and physical energy to fill and deploy so the boards which could be deployed in seconds were great.  Older folks new what signs to look for and the younger folks would follow their lead! and at the end of the day it if it didn’t get right to you great, you just unslotted the board!

I think in the last 30 years there’s been a push for housing that has lead to people building on natural flood plains and it doesn’t take a genius to work out what happens next. More recently here they are moving away from trying to get water to go from A-B as fast as possible and going back to more natural ways of slowing water higher in the catchment areas with wider soak areas and increased vegetation.  This has the advantage of giving those further down stream a little more warning time.

I dislike sand bags but as with all things preparedness, it’s about more than just ‘buy sandbags’! I remember Ubique talking about some of the measures she had taken for flood preparedness including landscaping so water runs away form her property and fitting an non-return valve on her wastewater pipe to prevent sewage backflow!

Over the years I’ve only once been worried may even be at slight risk of flooding, I seem to have always ended up in more elevated positions, now I’m wondering if that was sub-concious risk assessments.

I suppose it’s like most of these things – first identify the risks! are you in the situation like above or is your flood risk from sudden heavy rain?  What are your homes weak points when it comes to flooding? Doors/air bricks/drains/windows?  If you live higher up the hill you might plan differently than those living at the bottom! Can you get alerts to warn you of the potential for flooding? How much time will that give you to prepare?  Can you deploy your flood defence on your own? Can your other half or kids manage it if you aren’t there? Do you need just one defence or can you make your home a flood ‘castle’ with rings of defence? Does your community have a flood plan or volunteer flood response group? and I suppose the big one is, are you adequately insured?  I’m always amazed by how many people ‘loose everything’ in a flood because they had taken a ‘that’ll never happen to me’ attitude!

Food for thought anyway! Thank you BW

 

Or I can just line my doorways with a couple of my kid’s diapers. Those things are absorbent as heck! All kidding aside, this is a good idea to have on hand. Sand bags do take time to fill and are dependent on your availability to sand/dirt. And if you think you can just remove some dirt from elsewhere in your yard to fill them up with, then you are going to have a little pond after this flooding event. 

To be honest, the Amazon product that you linked to only seems to be semi effective against a doorway for very minor flooding since it only raises to 3.5″. I would want something more substantial for a garage door or around my home like in that 2nd link that you included in your post. 

 

Those are stackable as well.

 

That makes it an even better product then. Thanks for letting me know about it. I’m going to do a bit more research into them but am probably going to buy some for those just-in-case moments.

 

Dont forget you need one way flap or gate valves in your waste water / sewage pipes to stop flood water entering your home via the drains / toilet.

 

I bought my home 2-3 years ago and don’t know if I have this installed or not. Do you know how I can tell if I have one?

 

They are normally only installed in new builds that are built on flood plains, most people have to have them retro fitted. Here in the UK a few years ago many flood barriers were built by the local government and bought by home owners. but when the floods came they simply entered the houses by the drains and toilet.

 

in regard to the home sewage line backup restrictor – not always effective – even the uber $$$$$ ones >>> the hydraulic pressure involved in a flooding situation can be intense …

if building new or replacing the pipeline – doesn’t hurt to prep one into the construction ….

perhaps better and a positive alternative is to prep supplies to block all the home’s sewage outlets – includes basement floor drains, sink/shower drains, clothes & dishwashers, toilets ect ect ….

there are many methods – commercial products that utilize basic plumbing skills – expansion wedges that are braced into place will withstand even severe pressures ….

if worst comes to worst – capping off the drains with mortar/concrete limited to a cap depth using wadded paper/fiber ….

 

I’ve used quick dams before, they’re better than nothing but not exactly 100% effective.  Some of it might be my particular problem area, but here is the thing: they basically float.  They’re useful for redirecting small amounts of water but once the water level has reached 50% of their inflated height, they aren’t stable.  You can try and stack them, if you have a lot, but they will probably start to wash away and fail pretty critically.  

Also, they won’t ‘fill in’ the gaps between bags so water will still come through.  Like I said better than nothing but not a full solution unless your problem area’s meet their specific limitations.  

I end up using plastic sheeting in conjunction with quick dams for a infrequent problem area that kind of almost works, but honestly it just slows the flooding down.  My latest investment has been a submersible pump to pair with the aforementioned mitigation strategies (battery backup will be next, but its a small issue for me)

 

Having your flood barriers float away kind of defeats the purpose of having them… That’s not something I would have thought of so glad you mentioned it. 

How many times have you had to implement anti-flood measures on your house?

 

I have a low impact, infrequent problem area (very minor flooding once every two years in an unfinished basement).

Basically I have a basement door surrounded by concrete walls with steps leading up to ground level. During very high rain the water table briefly saturates and water comes into this ~3’x4′ sunken space (the concrete area is not waterproof). I’m able to “dam up” the door with a combination of plastic sheeting, tape, and quick damns but its not perfect.

So what happens is the dams help a bit at first but since its a small area the water level rises quickly. When it rises high enough the quick-dams are overwhelmed and basically “float” freely, but by the time that happens the plastic sheeting, and oddly enough the weight of the water, kick in to help (I think?). Then I bail/pump water by hand for two hours while a small trickle of water comes in through the edges of the door where the sheeting doesn’t quite work well enough. This only happens during intense rain conditions and its easier to stay on top of the outdoor flooding than deal with surrendering to the indoor flooding.

The way I deploy the sheeting is I fold it over on itself to make it thicker, and sort of “close the door” on it, so part of the plastic is inside the house with a folded edge (mostly water proof) around both the bottom and lower sides of the door and the rest is outside and can be spread up/out and either taped up or held down with dams (until water weight takes over).  Some water can squeeze between the door but its the best I can manage.

It’s a kludge of a fix, but it’s only happened twice in 5 years without causing any real damage, just frustration and clean up, and I learn more each time. Hence, the electric submersible pump is my latest upgrade. One day I’ll do a proper sunken sump pump with battery backup, just not an urgent enough issue to tackle properly yet (but probably when I finish the basement…).

 

https://www.insurancejournal.com/news/southeast/2021/07/27/624381.htm

Good afternoon,

The above article explains how a big company – Duke Energy – addressed a flooding problem.

The Duke metnod is not for the typical homeowner but can generate ideas.

After all, most of prepping is thinking and only then physical preparing.

 

It warms my heart to see a utility company actually doing something to be prepared and to provide more reliable and consistent service to it’s customers!

After reading your included article Bob, I wanted to visualize what these flood walls would look like around the substation so I found an accompanying video that briefly shows it.

For the typical homeowner, what if they improved their existing fence around their property making it water tight and strengthened and then have a gate that can be placed over the opening of the entrance to seal it up there as well if a flood is predicted to be coming in. This is similar to what Duke Energy is doing and I could see it potentially working.

 

I came across another instant sandbag by StormTec. It’s a 1 pound burlap bag that can suck up 5 gallons of water and turn into a 32 pound sandbag alternative. 

It looks like it does require a bit of prep work beforehand by soaking them in fresh water, but it beats storing and filling pounds and pounds of sand.