Formula for anti-seep collar 1

[drhenne]

Does anyone know the formula (or table) for calculating the size and number of anti-seep collars required to increase seepage length by 15% or better in a detention pond ? Also, are there anti-seep collars available for 8"ADS12 pipe ?

 

[cvg]

if this is a "dam" - the current practice is to install a system to control the seepage such as a filter diaphragm. This will intercept the seepage, and convey it through the embankment effectively eliminating piping or erosion. Seepage collars have not proven to be particularly effective.

For a non-critical application, use could use Lanes' weighted creep method. (E.W. Lane 1935)

the weighted creep distance is the sum of the vertical creep distances Lv, plus one third of the horizontal creep distances Lh. The weighted creep head ratio is given by the following formula:

Cw = (Lh+3Lv)/3Hdf

where Hdf is the effective hydraulic head

seepage is controlled by increasing the seepage length by using cutoff walls, collars such that Cw is increased to a conservative value. recommended values for various foundation materials are:
very fine sand/silt 8.5
fine sand 7.0
medium sand 6.0
coarse sand 5.0
fine gravel 4.0
medium gravel 3.5
coarse gravel, cobbles 3.0
boulders, cobbles, gravel 2.5
soft clay 3.0
medium clay 2.0
hard clay or hardpan 1.6


Chuck
cgopperton@stantec.com

http://www.stantec.com/

 

[elizasue1]

Check with you local NRCS (formerly Soil Conservation Service), the area engineer has a formula to calculate number and location of anti-seep collars. I also agree with the previous response, NRCS utilizes recommends the use of a sand filter diaphragm in all situations except when tailwater is present. Hope this helps. I work with NRCS in South Carolina and can provide the worksheet.

 

[KenYeomans]

We call anti-seep collars "Baffle Plates". The term was coined back in the early 1950s by my father P.A. Yeomans. We have used them in all farm dams equipped with under wall pipelines which we call "Lockpipe Systems".
We usually use ten baffle plate pairs. There is plenty of info on the

http://www.keyline.com.au

web site. The particular page for baffle plates and the recommended placement is

http://www.keyline.com.au/form02LP.html

Regards,


Ken Yeomans
yeomans@keyline.com.au

http://www.keyline.com.au

Agricultural consulting; property planning for sustainable agriculture; bio-organic soil regeneration and Landcare; contoured farm photomaps for remote planning; water conservation; flood irrigation of hillside & plains. Lay-pastor; publisher; computer &

 

[intrigueing]

Agridrain sells neoprene anti-seep collars for use with corrugated HDPE.

http://www.agridrain.com/pipeproduct.asp?prodtype=104