cofferdams

[finegg]

I am interested in knowing when you need to install sheet piles, or when you can get away with using something like jersey barriers or sandbags as protection. I will be working with a bridge construction over a stream that has a mean flow of 1 ft3/s. Please help, as I have no experience in construction.

 

[krd]

finegg, it depends on the depth of water and whether you need to excavate below the stream bed.
If you just need to divert the stream to dry out a work area then a wall designed to withstand expected head and built on the stream bed would work. Search for "porta dam" on internet for an alternate to sandbags which is good up to about 8 ft head. Pumps inside would take care of leakage.
If the water depth is going to be greater than that then use sheetpile. Also if you need to excavate below the stream bed then you need to drive sheets first since there is no good way to excavate in the wet and install a wall to seal and dewater afterwards.

 

[donham]

if you site allows ... you should consider a earth dam and an underground pipe/siphon thru the site ... 1 cfs is not much water

 

[gtrainor]

I agree with donham, 1cfs is small and just piping it through your site could work. You could also create a pool on the upstream side and pump it with a trash pump through your site. I would suspect that a 4" pump would do the job.