Significant creek bank erosion issue potentially threatening house.

Significant creek bank erosion issue potentially threatening house.

Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes

Not really a DIY task, but not sure where to post so I stuck it here. moderators please move it to appropriate forum if there is one more appropriate.

We have a property that is on a heavily wooded 2 acre lot with a seasonal creek, seasonal as in when it rains, the creek has water.   The house sits very close to the creek, maybe 12' or so on one back corner.  A deck off the house goes to within a few feet of the creek bank.

The creek wall is 10' to 12' foot high off the back of the house.

On the other side, the creek back slops gently up into the woods, so no concerns on that side.  The creek turns a little right at about the corner of the house and right at the turn area there is significant undercutting of the rock.  The first picture below shows what the creek wall looks like approaching the rear of the house,  the second picture shows the undercutting of the rock wall at the creek level, the third picture gives you a better idea of where the house and deck are in relation to the creek wall.

We've owned the property a little over 3 years.  I didn't even consider the creek as an issue when we bought the place.   We probably paid not much more than land value for it, and it included a 2100+ sqr ft log cabin home and a 1800 sqr ft shop (insulated metal building, very well built).  The log home had been neglected for many years, livable, but with issues.  We fixed up the home and our son and his family lived there for 3 years.  He recently moved on and we have moved into it.  

We were down in the creek area cleaning up debris a month or so ago and that's when it hit me that erosion could be a problem.

We have bids from a couple companies that specialize in erosion control such as this to shore up the wall.  They both propose what they call a 'bag wall', which is basically special concrete bags stacked up to form a wall.  A footer is cut into the creek bed, and rebar is used to keep the bags in place.  The area behind the wall would be filled with gravel and it would have drains to allow any moisture that gets behind the wall to escape.   The concrete bags are perforated and over time they erode away and you are left with a concrete block wall.  These bids have come in at $42K and $52K.  Both companies say this type erosion is common here (North Dallas Area) and bag walls are a permanent solution.

FYI - house was built in '84, shop in '04. 

Has anyone had any experience with an erosion issue such as this, and if so, how did you address it?

Thank You,

Kevin

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Investor · Dallas, TX · Member since 2014 · 2k+ posts · 1k+ votes
12y
Originally posted by @Roy N.:
Originally posted by @Hattie Dizmond:

white rock = local colloquialism  (aka...chalk, as in "Chalk Hill" in Cedar Hill) translation...Slate  ;-0

 Interesting ... here slate & shale are grey - brown, but gypsum & limestone both appear like the bank in the photos above.

You know...I was having a really, really, really bad night!  Slate & Shale are gray & brown here too.  I meant to type limestone.

I think I'm going to take a weekend off from RE.  As much as I love it, it has eaten my lunch (and breakfast & dinner) this week.  I have a deal that I've busted my a@@ on that now looks like it isn't going to close, even though the seller is ready to sign.  Now, since everything I going to type is going to sound like whining, I'm going to go have some cheese, before Brandon Turner shows up and tells me to do that!!!!!!!!

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  • Investor · Dallas, TX · Member since 2014 · 2k+ posts · 1k+ votes
    12y

    @Kevin C. 

    Yeah...that's white rock.  Very common in this area and very soft, so it erodes quickly.  If we got more rain, your problem would be a lot worse.

    The concrete bag solution is pretty common around here.  My family owned a bunch of property up I Cedar Hill, which they sold to make Joe Pool.  Cedar Hill is basically solid white rock at about 4 - 6", and there was a lot of bag solutions for the erosion issues they had. 

  • Real Estate Professional · West Palm Beach, FL · Member since 2012 · 23k+ posts · 13k+ votes
    12y

    Perhaps traditional rock rip rap, as opposed to the bagged cement rip rap?  Assuming you have the room, would need about a 1:1 slope (45 degree angle).  Fill the void, to the 1:1 slope with stone(1/2"-2" size), filter fabric, then a 2' layer or so of 6"-18" rocks.  Don't know the availability/cost  of sound rock in your area.

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    Yep, most of the rock is soft and flaky, but there are parts where it is very hard and not flaky at all.   We can address the soil erosion up top with plants, but the wall erosion, that I guess I'll need to have addressed.   Not sure if we should monitor it first since at this point we don't know how quickly the erosion is occurring, or just bite the bullet and have it done now.   The people that looked at it said it's good there is rock there, even though it is mostly a soft/flaky rock, they say it is substantially stronger than if it were just dirt.

    It could be the creek wall holds for another 30 years, or it could let loose who knows when.

    Pay now, or pay later when the hand is forced...

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    @Wayne Brooks I don't think a 1:1 slope would work, the creek walls are about 12' and a 1:1 slope would put us too far into the creek bed   Both companies we met with said bag wall when they saw what we were dealing with.

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    One company said he could just go 6' or so up and save us about half, the issue there is if the creek were to ever come up over that 6' level, the water could take the wall down.   I don't believe the creek would ever come up that high, but I don't know that I'd risk a bag wall coming down on that assumption.

  • Investor, Entrepreneur, Educator · Springfield, MO · Member since 2009 · 21k+ posts · 12k+ votes
    12y

    Rock, guessing 4 truck loads. Common here as well but that is deeper than most here. Won't be cheap but doesn't look like you have a choice unless you want a houseboat.

    Lots of ways to attack it, chain link over rock is used here as well in flash flood prone spots, they'll drop some boulders, like 3' to hold rock fill. More $$$$ is a sea wall approach then backfill.

    Might ask your conservation department too, if that's a public creek they might help and even if its not they will have engineering solutions. :)

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    @Bill Gulley  Great suggestion, just emailed the conservation district for this area to see what suggestions / ideas they may have.  I forget the number, but one company I think was saying something like 10 to 12 truck loads of material.   Both companies have suggested 100 to 120' of bag wall ranging in height from 10 to 14'.

  • Investor, Entrepreneur, Educator · Springfield, MO · Member since 2009 · 21k+ posts · 12k+ votes
    12y

    Wow!  $$,$$$ Good luck.

    I didn't see all the pics, that  is bigger.... :(

  • Builder / Developer · Newnan, GA · Member since 2013 · 98 posts · 33 votes
    12y

    Local laws may vary but be sure that this is not a state water way. Fines for doing any construction in a state waterway or its buffer without appropriate permitting could be significant. Be very cautious.

  • Bill S.Pro Member
    Moderator
    Rental Property Investor · Denver, CO · Member since 2013 · 4k+ posts · 2k+ votes
    12y

    @Kevin C. the work likely falls under the jurisdiction of the Corps of Engineers. You would need a permit to perform the work that the companies suggested. Perhaps I can be done under a general permit but the local office should be contacted to verify. Penalties for failing to obtain the permit, if necessary, are significant.

  • Bill S.Pro Member
    Moderator
    Rental Property Investor · Denver, CO · Member since 2013 · 4k+ posts · 2k+ votes
    12y

    Should read "need a 404 permit"

  • Roy N.Pro Member
    Rental Property Investor · Fredericton, New Brunswick · Member since 2013 · 7k+ posts · 4k+ votes
    12y
    Originally posted by @Hattie Dizmond:

    @Kevin C. 

    Yeah...that's white rock.  Very common in this area and very soft, so it erodes quickly.  If we got more rain, your problem would be a lot worse.

    The concrete bag solution is pretty common around here.  My family owned a bunch of property up I Cedar Hill, which they sold to make Joe Pool.  Cedar Hill is basically solid white rock at about 4 - 6", and there was a lot of bag solutions for the erosion issues they had. 

    "White Rock"?   It looks like limestone in the pictures.

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    I was told it was a mixture of shale and limestone.  There are parts that are very solid and other parts that are soft/flaky.   

    I'm leaning towards having the bag wall put in, it shores up the creek wall and top side erosion all at the same time.  

    Here's a link to more pictures for your viewing pleasure.

    More pics of erosion issue

  • Real Estate Investor · Central, TX · Member since 2012 · 479 posts · 165 votes
    12y

    From where I'm sitting, I'd say you're going to have an erosion problem at grade first. I would try and shore up the areas where those deck supports are. Are they cemented in into the soil or are they set down into the rock? 

    I've never been fond of those bag walls myself, and at the cost quoted, it sounds ridiculous. 

    If it were my place, I would look into a "shotcrete" solution. Basically drill into the rock and form a rebar cage around the rock. Then shoot it with a concrete layer, much like a pool is formed. If you're just trying to control erosion, which is what it looks like, then you just need a barrier that is going to stand between the rock and the swift water. You could probably hire out or perform the driling and rebar aspects yourself, just have a crew come in and spray the concrete; surely you could achieve this for less than $42,000.!  

  • Investor · Dallas, TX · Member since 2014 · 2k+ posts · 1k+ votes
    12y

    white rock = local colloquialism  (aka...chalk, as in "Chalk Hill" in Cedar Hill) translation...Slate  ;-0

  • Roy N.Pro Member
    Rental Property Investor · Fredericton, New Brunswick · Member since 2013 · 7k+ posts · 4k+ votes
    12y
    Originally posted by @Hattie Dizmond:

    white rock = local colloquialism  (aka...chalk, as in "Chalk Hill" in Cedar Hill) translation...Slate  ;-0

     Interesting ... here slate & shale are grey - brown, but gypsum & limestone both appear like the bank in the photos above.

  • Investor · Dallas, TX · Member since 2014 · 2k+ posts · 1k+ votes
    12y
    Originally posted by @Roy N.:
    Originally posted by @Hattie Dizmond:

    white rock = local colloquialism  (aka...chalk, as in "Chalk Hill" in Cedar Hill) translation...Slate  ;-0

     Interesting ... here slate & shale are grey - brown, but gypsum & limestone both appear like the bank in the photos above.

    You know...I was having a really, really, really bad night!  Slate & Shale are gray & brown here too.  I meant to type limestone.

    I think I'm going to take a weekend off from RE.  As much as I love it, it has eaten my lunch (and breakfast & dinner) this week.  I have a deal that I've busted my a@@ on that now looks like it isn't going to close, even though the seller is ready to sign.  Now, since everything I going to type is going to sound like whining, I'm going to go have some cheese, before Brandon Turner shows up and tells me to do that!!!!!!!!

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    @Ryan R.

    I didn't build the deck, so I don't know how deep that corner support goes, but we plan to demo the deck and rebuild it anyway.  The top side erosion I'm confident we can control with plantings.

    I thought the same thing about shotcrete. We've had pools built and the process they use to build the pool looks like it would work to shore up a creek wall.

    I've got an email to a company that does shotcrete to see what they think.

    I also have a contact I was given with National Resources Conservation Services here locally I'll be reaching out to to see if they have any ideas.

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    Spoke with owner of a local shotcrete company and forwarded him pictures of the creek wall.  He said he's addressed erosion projects like this with shotcrete and will be coming out to look at the creek early next week.  Hopefully shotcrete is a less expensive solution than the bag wall bids I've gotten so far.

  • Real Estate Investor · Central, TX · Member since 2012 · 479 posts · 165 votes
    12y

    Keep us updated. Interested to see how it comes out. 

    Also, find out the PSI for the bagwall concrete. I think shotcrete is closer to 5,000 PSI whereas the bags are about half that; I could be wrong though. Also, ask about fiber reinforcement for the shotcrete. I think it's popular for pool construction now to make the structure even stronger. Might be a good addition for this project. 

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    12y

    After being passed around a few times in the Soil /  Conservation dept I finally received the following response:

    There’s not much that can be done that won’t be expensive and involve an engineer. It is typical and normal for ephemeral creeks to erode the stream banks and move; they are active and this is part of their normal function in most cases. Your best bet is to consult an engineer or follow-up with the companies you have already received bids from if you wish to protect your house.

    So, no help there, back to the Shotcrete guy.

    Shotcrete guy has come back with numbers based on him shoring it up how he has done similar jobs, but this one is more extensive than what he has dealt with in the past.  He reached out to a contractor he has worked with that does work like this for the highway dept and that person brought more info to the table.  Bottom line, shotcrete contractor is going to try to get the contractor that does erosion work like this for the hwy dept and an engineer that he's worked with all out to take a look and give me their thoughts.  At this point, the shotcrete solution looks very promising, but I don't have any numbers yet from the hwy dept erosion contractor on his anchoring solutions or any feedback from an engineer that deals with these sorts of issues.

    As soon as I meet with all the contractors mentioned and get more info from them I'll post what I find out.

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    11y

    I've got it all in order now.  Have permit in hand from City for the work and have signed off with the steel guys giving them the go-ahead for the work.

    Had to submit an engineer's drawing and statement that what I'm doing will have no impact on downstream properties.  Upstream will not be impacted since we will not be changing the course of the water nor restricting it, the wall we'll be putting up will follow the contour of the existing creek wall.

    One company will be doing the steel work, setting the anchors into the creek bed and creek wall and installing all the steel mesh.  Second company will then come out and do the shotcrete.

    I've already had several dead/dying trees removed from the creek wall to get it ready for the steel work.

    We're tentatively scheduled to get started with the steel after the holidays, so early January.


  • Developer · Garland, TX · Member since 2008 · 8k+ posts · 4k+ votes
    11y

    What's it going to cost, Kevin?

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    11y

    Total all in cost should be in the low 20's.

  • Investor · McKinney, TX · Member since 2009 · 405 posts · 160 votes
    11y

    Wall was just completed.  Took just under two weeks start to finish. 

    First contractor came in and set all the anchors (steel rods spaced 6' apart, minimum 5' into rock, 3 rods every 6', one into creek bed, two into creek wall) and installed steel mesh and chimney drains, that took a little over a week. 

    Shotcrete contractor came out next day after all the steel was done and had all the shotcrete done that day.

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