High tide problems - What are the solutions?
- Thread starter BigBrother
- Start date
I would not even try to build a pool on the property. If (really when) it fails like the pic shared above YOUR name will be connected to it. I would not want that to happen as it could sink your good name 
- Oct 25, 2015
- 5,809
- Pool Size
- 28000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
*** Edited this since I just realized you are the involved in performing the work***
BB,
Hard for me to tell from the photo but this doesn't look to me that it's just tidal water. King tides happen all the time and should not cause this. Any chance you got one of those random downpours that filled this hole up? This will happen any time you have a hard downpour even with well points but should quickly pump down. I'd take a look at the design basis and geotech work that should have been used by the engineer to do the structural design. Is there a note of some kind that indicates a retaining wall if required is outside the scope of his design? Pools on the water edge almost always require this but not always. Depends entirely on what's below the surface rock or mud. I've done sheet piling in S Louisiana for shore bases where the crane had to hold on to each piece of piling or it would drop like a rock and could never be found. Sometimes this would happen up to the first 3 sections! No matter what we did I'd have to come back every 5 or 6 years to repair it. Other places it was hard to even dig without some blasting.
Looks from the photo the floor elevation of the garage behind the pool is similar to the pool. What's the river? If it's a navigable waterway the Corps of Engineers would likely have some jurisdiction/requirements and I'm quite certain your engineer that stamped the drawing would be aware of this. Can you get a copy of the stamped design drawing(s)? That should shed a lot of light on this. What is your role on this project, GC or sub and if so what sub?
I hope this helps.
Chris
BB,
Hard for me to tell from the photo but this doesn't look to me that it's just tidal water. King tides happen all the time and should not cause this. Any chance you got one of those random downpours that filled this hole up? This will happen any time you have a hard downpour even with well points but should quickly pump down. I'd take a look at the design basis and geotech work that should have been used by the engineer to do the structural design. Is there a note of some kind that indicates a retaining wall if required is outside the scope of his design? Pools on the water edge almost always require this but not always. Depends entirely on what's below the surface rock or mud. I've done sheet piling in S Louisiana for shore bases where the crane had to hold on to each piece of piling or it would drop like a rock and could never be found. Sometimes this would happen up to the first 3 sections! No matter what we did I'd have to come back every 5 or 6 years to repair it. Other places it was hard to even dig without some blasting.
Looks from the photo the floor elevation of the garage behind the pool is similar to the pool. What's the river? If it's a navigable waterway the Corps of Engineers would likely have some jurisdiction/requirements and I'm quite certain your engineer that stamped the drawing would be aware of this. Can you get a copy of the stamped design drawing(s)? That should shed a lot of light on this. What is your role on this project, GC or sub and if so what sub?
I hope this helps.
Chris
Last edited:
- Oct 25, 2015
- 5,809
- Pool Size
- 28000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
PS When sheet piling or retaining wall is required I always did this before any other civil work in the area. Puzzling to me is the house or building right behind the pool. Seems like the piling would have been required for it as well unless it's very old and there's been a lot of erosion.
Sink, no pun intendedI would not even try to build a pool on the property. If (really when) it fails like the pic shared above YOUR name will be connected to it. I would not want that to happen as it could sink your good name
Answering both of your posts in 1 reply.
I am GC on the project, owner of the pool company.
Water way is a sound leading to the ocean.
Yes, I am shocked that a sea wall is not required here.
What isn't shown in the picture is the water was nearly above the road...
This was all from king tides, no rain in the past few days.
Apparently this king tide is about 3.5' higher than normal high tide.
After more discussions with multiple engineers:
The only viable solution is piles every 6' on center.
12" slab pour for the base with #5 @ 12" OC double mat.
The work would have to be started and completed in between king tides.
That's just so the pool doesn't float away. We haven't discussed what work is necessary to make an elevated deck remain put.
Honestly seems like the bottom floor of this house could be under water if the sea level rises 1-2' on a king tide.
Never seen anything like it.
- Jul 16, 2012
- 7,282
- Pool Size
- 27000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
Thanks for the update. You're in a tough spot. I'd be interested in how forward looking the engineering design of the pool is (to say nothing of the house) considering the direction that ocean levels are going. If I owned that property (I could have but we chose to buy higher soundfront land) I'd spend my $100-150K raising the house up 9' and sleeping well at night, and putting in at least an oyster sill/marsh/riprap (or some combo) shoreline. Not sure if a fiberglass sheet pile seawall would be a great solution to allow a pool (though it would certainly stop erosion) since it's going to be overtopped (or flooded around the side) anyway since the native elevation isn't sufficient to remain dry in a well lined-up hurricane scenario. We are having this conversation about a tide level that occur numerous times each year! Seems like they are only adding to their worries by building a pool.
I know it's not your call, but the homeowner should have the foresight to "look around". Some lots (many actually) aren't long for staying dry, and aren't well-reasoned lots to build pools or ground level homes on. A rising tide may lift all boats, but it also lifts (and destroys) a lot of "permanent" things that are built at lower elevations than they should be.
I know it's not your call, but the homeowner should have the foresight to "look around". Some lots (many actually) aren't long for staying dry, and aren't well-reasoned lots to build pools or ground level homes on. A rising tide may lift all boats, but it also lifts (and destroys) a lot of "permanent" things that are built at lower elevations than they should be.
Had the long conversation with the homeowner yesterday.
They like the sea wall and piles approach and were not scared off by costs.
The property is on a sort of peninsula on an island. They also own the two lots next door and it's not the primary residence.
I too would be scared about the longevity of a house that is surrounded by water once a month, but homeowner seemed unconcerned.
I like the sea wall approach if it's possible as it could raise the entire yard ~3' and make construction much easier.
My Parents had a house in Virginia Beach on an Island ( Bay Island for any locals). Similar setup with water on 3 sides of the house (front yard looked at neighbors back yard across the canal) Their house was on a raised foundation and sat about 6 feet above grade. Flood zone AE, Any sort of nor easter surrounded the house with water, even with a full rip rap sea wall they had multiple foundation issues over the years and the house was constantly settling. Can't imagine a pool at grade level doing any better. The houses along the ocean here have pools but are usually on raised decks and if at all in the sand only partially.
- Oct 25, 2015
- 5,809
- Pool Size
- 28000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Sorry for the delay again. I was out all week for unplanned business.
That's gonna be a pretty amazing pool if you keep the location! As an added level of protection maybe you could add a removable plug. I've build large concrete barges on Hainan Island in the S China sea that were used to make a dock for a gas processing plant to produce gas from two platforms about 60 miles off shore on the southern tip near Nanshan. Here's a Google Maps link to the facility. Construction finished up in 1995. You can see an image below. The barges were huge about 10 meters deep 20 meters wide and 60 long as I recall. We built 6 at a time in a dry dock up the coast at a naval facility. Poured the base, then used a huge slip form about 2' deep for the walls that was connected to the vertical rebar all the way around the outside. As the concrete was poured into the slip form we jacked it up with jacks all around that powered it up. As the concrete dried we jacked it up all the way up to 10 meters. We also installed a plug valve in the concrete and towed the barges into place for the end structure in the photo. Got the barge in place then opened the plug valve to sink it with barge cranes to put it in place. Then filled the barges with rock and topped the structure with concrete road. I guess I got a little off topic but I was thinking you could install a removable plug when you pour to help prevent floating the pool as protection if you miss the tides. They do that for most pools around here in S Florida since we're a couple feet below the water table. Water seeps in continuously so we have a perforated direct line about 6" below the bottom of the concrete floor that's in a layer of gravel. Kept a pump running all the time as concrete set and it worked fine. Just before we installed the plaster the plug was sealed up and the drain plugs were installed.
I hope this is helpful.
Chris
