Stream Channel Stabilization

[alchemon]

Hello all,

I have heard quite a bit about stream bank stabilization techniques but nothing about stream channel stabilization. Is formal stream channel stabilization even feasible with the current USACE general permits (I don't think so) as I think any armoring technique threatens to change the stream's profiles. Perhaps some kind of thin matting across the channel might work like we do on man made ditches, but it seems unlikely that it would be permitted?

Thank you

 

[cvg]

channel stabilization doesn't have to change the profile. It is normally limited to grade controls and those are usually constructed at road crossings. you can get a nationwide permit for a transportation project (road crossing NWP14).

It might be time consuming and more expensive, but you can get an individual permit.

 

[alchemon]

Outside of setting a box culvert or bridge pier into the channel, do you have anything else in mind? For example, I doubt you could pull a permit for riprap in the channel unless it was local to assist scour around culvert/piers.

What if you had something more like a linear sewer utility crossing and you wanted to stabilize the channel with the banks?

 

[nackra]

Reference that might be useful:

https://directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=17816.wba

 

[cvg]

57 and 58 address utilities crossings. again, most utility crossings occur at road crossings - bridges and culverts

NWP 57 – Electric Utility Line
NWP 58 – Utility Line

https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll7/id/19757

 

[1503-44]

Gabion mattresses and blocks work quite well.

https://duckduckgo.com/?q=gabion+mattress+images&t=brave&iax=images&ia=images

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[cvg]

gabions are good for banks, not as good for channel bottom
plain riprap, grouted riprap and boulders
soil cement / roller compacted concrete
piles
concrete cutoff walls

https://udfcd.org/wp-content/uploads/uploads/vol2 criteria manual/09_Hydraulic Structures.pdf

 

[TerryScan]

Is a bore out of question for the utility crossing under the stream?

 

[alchemon]

Hello all,

Thanks for all the responses. To answer a few questions:

1. Yes on certain projects HDDs/trenchless are feasible/economical, on others they are not.

2. The utility line general permits require that the elevations be returned to the original condition. I don't see how you can argue that this is feasible with riprap.

3. The utility general permits indicate that the crossings cannot impact aquatic habitat. I don't see how this would be feasible with a concrete bottom unless you were just replacing rock.