Thread: Need Help w/Driveway Bayou

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We had an idea this year to build a "bridge" out of some old fence boards from the bottom of our driveway up to our garage. My husband had an idea to build a "Swamp/Bayou" on the sides of it to give us more of a swampy feel and makes our guests feel like they are really walking over a swamp.

We have hit a roadblock though and need some help or direction. We have the plans all laid out but are concerned about the wood not holding up to the pressure with the amount of water we will need to put in it (and the slope of our driveway)

Here are our preliminary plans. Do any of you have any ideas on how we can reinforce this so it will hold up? We are trying to do this as inexpensively as possible and had planned on using 1x3's to build each frame with some 8 mil polysheeting to hold the water.

Top View of driveway/bridge:


Side view of open bottom "boxes" to hold the water:

Just a suggestion but what about if you built water tight boxes around each of the bridge supports and filled them with fake moss (or shredded green tissue paper?) that way the water wont touch the wood.

The water really isn't going to touch the wood. There will be two of these "boxes" (really just frames) on either side of the bridge so the bridge will not actually be in the water. The inside of these boxes will be covered in the black poly to hold in the water. We are more concerned about them not holding up to the pressure of the water.

Brace the walls from side to side internally.

I see, then i would say build the boxes with pieces in between the water boxes about 2" wider than your bridge, then build the bridge in the center and that way the water will be putting the pressure on the cross pieces but not the bridge it's self. I don't know what your budget is like but for the cross pieces I'd use 2X6's on edge they would take anything you could throw at them and are fairly inexpensive. Hope I could help great idea by the way

I can't make out your measurements perfectly. But a rough estimation would put that at about 150 gallons in each basin. That's about 1200 pounds of water. Another rough guesstimate puts it at about 20-25pounds per square foot on the sides of the basin.

Looking at your plans, you are pretty much just over 24'. I'd suggest using 8 foot lengths of board, and only use 3, to make it 24 feet long total. This will one, save you on materials and, two, save you a lot of cutting.

I don't think you need anything for the bottom. However, you do need some type of bracing/gusseting. I'd recommend triangle gussets in the corners and then vertically from the sides to the ground every 3-4 feet. For some extra rigidity, you may want to run braces between the vertical braces parallel to the sides of the basin, it may not be necessary though depending on your surface.

This sounds like a really awesome idea. I hope you are able to pull it off and post some pics.

What about using PVC and poly sheeting instead of wood? I think it would work if you just made 2 big rectangles about 4"-6" high with T fittings every so often to keep the top and bottom at an equal height and just let the whole frame rest on the natural slope of the driveway (instead of compensating with extra height on the bottom). To ensure that water doesn't overflow on the bottom, I'd use a submersible pump to draw the water from the bottom back to the top and come out with something like a soaker hose/drip line/or piece of perforated PVC. This would have the advantages of A) not using 40,000,000 gallons of water and B) the pump would give you the 'sound' of water moving which I think would be important to this type of effect and C) PVC is cheap, portable, and should be able to take the load IMO.

I wanted to thank everyone for all the suggestions. We got it all put together this evening and it turned out great!! Thanks again for all of your helpful advice.

Here are a few pics of how it turned out. Please excuse the mess. We were still working on getting the garage ready.

Some flash shots:




Some without flash:

HOLY COW...this is amazing! I am terrified of water and would never be brave enough to cross that. It would also be neat to add a shack and a swamp witch another year....good job!

That is totally way cool! Where did you get the "Croc"? I would love to have one for my haunt!