Santiago
Ultra Nomad
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Registered: 8-27-2003
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Question for Rip-Rap specialists
This photo is few days after the Gecko flood. The embankment is about 4 or 5 feet closer to the cabin and the rocks that 'protected' the old
embankment are about 200 feet down stream. The next photo is mid-way through the flood - the water eventually washed away the rocks that are there.
I have piled up some rocks now but know that within a few years, another storm will wash them away and I'm not getting any younger so I want to do
something that will not wash away. I have access to a bunch of 4' pressure treated peeler core logs and was thinking of driving them a few feet into
the sand and then piling the rocks behind that. Also, I'm limited to smaller sized boulders that an nearly 60-year-old with a questionable back can
lift on to the back of a pickup and then put in place. Can I grout the boulders in place? This is not worth spending much money on but whatever I
do, I would like at least a chance of success come the next storm.
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woody with a view
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try driving some 1.5" galvanized pipe about5' down. if you can find it get some chain link fence and use it as a mesh with your rock and concrete it
all into a berm to divert the water. use the posts to anchor the whole thing in place. good luck!
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Barry A.
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It is tough fighting nature, but you are on the right track------Woody has a great idea that I have seen work in the past when the floods are
"reasonable". When the "big one" hits, there is really nothing you can do but watch--------usually man is no match against nature..
Barry
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JESSE
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I don´t think theres much to do against a raging arroyo.
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Russ
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Woody's idea will definitely work. I did a similar jobs in WA. and they held thru storms. Big thing is drive the posts as far as possible. We used a
90# jack hammer and went till the 2" galv pipe stopped. I've seen foundations in unstable soil done with the pipe first too. You have to make it so
the storm waters can't get behind it or all is lost. Good luck
Bahia Concepcion where life starts...given a chance!
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tripledigitken
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Rip Rap
Santiago,
This is how it should be done in a perfect world. The "toe trench" is the key to success with your project. The next key is to line the slope and
trench with a Geotextile Fabric (Mirafi 700x or similar). 1/4 ton rip rap (2' longest dimension)would be perfect given the size of the job.
Grouting is an excellent way to finish the project. Just pour concrete in the voids leaving the tops of the rip rap exposed. With this design beams,
posts etc. are not necessary.
The amount of soil to excavate is about 1 cy per lf of Rip Rap, ie 70LF of R/R 70 cy's. Alot of digging by hand, an easy 2-3 hours with a small
backhoe!
Good luck.
Ken
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arrowhead
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I looked at your picture. Those rocks you have lining the arroyo are not riprap. They are just river rocks. For riprap to be effective the rocks have
to be too heavy for the current to wash away. You will need granite rocks weighing between one-half to one-ton each to line that arroyo. That works
out to a rock that is about 2-feet per side. The metal fence is a decent idea, but you will still need to place riprap in front of it to prevent the
water from getting under it.
It looks like you are on an alluvial plain. The sand could be 100's of feet deep there. I really don't think there is any cost-effective solution to
your problem. You would have to riprap the arroyo all the way upstream to prevent to water from changing course upstream and working around the
riprap.
You may just want to try having a bulldozer deepen the arroyo near you and push the sand into a berm on your side. It will only work on a smaller
gully-washer storm.
No soy por ni contra apatía.
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Barry A.
Select Nomad
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I think that if you have a "bull dozer" at your disposal, a large V shaped dike several thousand yards up slope from your housing complex might be
more effective----------I notice that is the way they have successfullly protected many housing areas in the Borrego Springs area, and it seems to
work with the "normal" storms--------as said, with the 100-year storm nothing is going to really help that much--------where the water actually goes
in a big storm is always problamatic, and it often goes where least expected on a desert alluvial bajada.
Barry
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Taco de Baja
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You could also try planting some palm trees or mesquite trees close together. The roots will help to hold in the soil and also deflect the surface
water. Plus they look nice.
Truth generally lies in the coordination of antagonistic opinions
-Herbert Spencer
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