Need help with pool type and flood issues

[oneman546]

Hi everyone, great forum with, wow, lots of info. Been reading for months trying to piece together what I want. However my situation is very unique, at least it seems to be. I have talked to several PBs and have not found anyone really interested in tackling the job.

So, I live in Biloxi, MS in a waterfront home, a home that had serious flood damage in Katrina and had 2' of water in our basement in Aug from Isaac. I know I can't build the pool high enough to avoid all flooding like we saw with Katrina but I do want to build it high enough to defeat the every couple year flooding like we saw with Isaac. So I'm looking to build the pool within a retaining wall. Pool depth not to exceed 5'.

What I want to do is install a pool basically on top of the undisturbed ground just removing the upper part of the slope as needed, next build a retaining wall around it, then install a french drainage system within, and finish up by backfilling with clean crushed gravel compacted in lifts. Of course after that I would have a deck poured. My thought is flood water could enter and exit the cavity without the backfill getting sucked out.

I'm open to vinyl, fiberglass, or gunite/shocrete but we really like gunite.

So my questions are:
1. Does my gravel backfilled retaining wall concept sound feasible? Suggestions...
2. Which type of pool would install and work best in a wall as described?
3. If I build the pool lower, no wall, and it did flood, what kind of problems could I expect? Just cleanup? Which type of pool would do best?
4. Will a flooded pool pop out of the ground? Liner float up?

Here a few photos of my home and the pool design with wall that I'm thinking of. Thanks for any help.

 

[257WbyMag]

Did any of the PBs that you talked to give you any indication as to why they wouldn't consider doing this job? Do any of your neighbors have pools?

 

[oneman546]

Inexperience building a pool within a retaining wall seems to be the main reason. Specifically, concern over the ground becoming saturated during a flood and the wall giving way or the pool shifting. During Isaac, the water came up to where the ground meets the driveway retaining wall and remained for 24-36 hrs. It's been very frustrating trying to locate an experienced builder. I have yet to meet a PB that speaks knowledgeably on how to deal with my issues. That's why I've come here.

I have one neighbor with a fiberglass pool elevated in a retaining wall but his PB isn't around any longer. It was build post Katrina. His property is not water front and did not flood during Isaac. It's been up six years though and he hasn't had any problems. However they backfilled with dirt and sand. I'd bet good money there are voids. My driveway is caving in because the backfill is eroding from under it. This why I wanted to go with gravel and a good drainage system.

The more I think about this, I wonder if the expense and headache of elevating the pool is worth it. I'm considering just building the pool a couple of feet above grade and just put the money saved aside for flood damage repair.

I would really like to hear from members with any experience with pools that have gone under in floods? Aside from pool equipment damage, what happens to the different types of pools? Which type fares best?

Thanks

 

[msudawg]

I am no expert on the project you are considering but I can tell you, having grown up on the water in Biloxi, that what you are wanting to do can be done. I grew up on back bay (Lake Villa area) and my parents along with several neighbors built pools on fill dirt. It sounds like you have a solid plan to handle drainage and erosion risks in the area where the pool would be but do you have a retaining wall where your property meets the water? If you are not in a hurry to get the entire project completed I would hire an expert in landscaping to install an EP Henry retaining wall system and perform the backfill and grading. A properly installed EP Henry wall system, using geo grid and proper below grade support, will handle the weight of most anything. Tackling this job first, while letting the landscaping expert know your intentions to install a pool behind the wall, will allow you to get a properly installed retaining wall and postponing the pool project will allow for any settling of the project. Just my 2 cents on your project. BTW- I am jealous of your view.. I am guessing you can see the Popps Ferry Bridge from your back yard.

 

[oneman546]

I built an Anchor wall on the side of the house a couple of years ago and looks just like the Henry system. I swore I would never build another, 70 lbs. blocks suck, but it came out great and hasn't shifted at all. I've been thinking of building another with geo grid to hold the pool. I'm concerned that fill dirt will get sucked out followed by deck problems. I'm over analyzing this I'm sure.

We're near the mouth of Back bay.

I finally got a response from someone around the bend with a gunite pool. He's been flooded a few times and only had to clean it out. No structural damage.