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Permanent Erosion Control For Rocky Slope At 2H:1V

Permanent Erosion Control For Rocky Slope At 2H:1V

I would like some guidance for permanent erosion control measures for an existing rocky slope at an inclination of 2H:1V.  The maximum slope height is 25 feet.  Parallel horizontal benches are not feasible due to site constraints.  Slope is a structural fill slope built with a rocky fill material with a maximum rock size of 12-inches. Surface erosion is occurring on the slope face.  A good vegetative cover has not been established.  


RE: Permanent Erosion Control For Rocky Slope At 2H:1V

Have you tried an erosion control mat with hydro seeding?  If that is not viable then you can always line the slope with concrete, grouted riprap or even hand placed riprap.

RE: Permanent Erosion Control For Rocky Slope At 2H:1V

is it riprap or soil with a lot of rocks? 2:1 is probably too steep for riprap, especially if not angular rock. if soil, what is the soil type? Is it just rills, or is water coming off the top of the embankment? Would a soil tackifier work? Something like Soiltac or Gorilla Snot?

unless you can get good vegetation to grow, the permanent fix is very expensive, either flatten it to 3:1 or flatter or bench it or line it with a long term erosion protection such as concrete. 2:1 is simply too steep for an unvegetated slope.

RE: Permanent Erosion Control For Rocky Slope At 2H:1V

cvg isnt that tackifier pretty expensive.  One past project proposed something similar to stablize a 10' wide multi-use path.  If I remember correctly, it bid out at $20+/SY.  

RE: Permanent Erosion Control For Rocky Slope At 2H:1V

Both the tackifier and mat are expensive but are probably the only ways to promote vegetation, which will be the cheapest way to stop erosion of the slope.

Vegetation will be more difficult to achieve if you have a lot of rocks on the surface - exposing as much dirt on the slope as you can (be removing large rocks) will help the revegatation efforts.

If you are in a dry climate, watering during the first month is also very imporant, particularly for a 2:1 slope.    

RE: Permanent Erosion Control For Rocky Slope At 2H:1V



Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

RE: Permanent Erosion Control For Rocky Slope At 2H:1V

A wire reinforced turf reinforcement mat might be something to investigate.  This material (MacMat-R) has been used in the past to vegetate very steep soil nailed slopes and to vegetate erosion prone mountain slopes.  Has been used as steep as 1H:2V.  Wire reinforcement allows the use of rock bolts and such for heavy anchorage.

RE: Permanent Erosion Control For Rocky Slope At 2H:1V

Edgesaver from Filtrexx would work.  Goto, look at projects, then sawmill run.  I consulted the designing engineer about adding the gabions at the waterline.   

RE: Permanent Erosion Control For Rocky Slope At 2H:1V

If you think you will be able to get the vegetation to grow (meaning you have good topsoil cover and soil conditions), you could use coir logs or similar wattles spaced along the slope to slow the flow of water and minimize the erosion.  These are realtively inexpensive but would not be a long term solution in themselves, but would help get your vegetation established.  You would place these end to end horizontally along the slope in rows as needed.  The other advantage is that they are biodegrable and do not need to be removed.

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