Cofferdam Seepage Question

[JFitz]

Hello to all....

I've come across a somewhat simple cofferdam / seepage practice question that has recently keep me up at night. The solution is provided but I am confused on how the author has calculated the gradient. I understand the gradient is the head loss per unit length, H/L. Can someone explain to me how the author gets his length value used in the gradient calculation? Any help would be appreciated..

Take care.

 

[Santiagj]

I believe the length should be 6. I think the solution is incorrect. Anyone disagree?

Make sure you read the errata for your references. This will save your sanity. When I was doing practice problems in the CERM I came across 3 questions that were incorrect. 2 of them had errata that were posted. The third question I posted on here and we worked out a solution that was also not shown in the CERM.

 

[JFitz]

Same here. The distance through the soil where the head loss occurs is 6ft. Thanks for the comments. The bad news is that this reference doesn't have errata posted. I think I'm going to stick to more legit sample tests.