Estimating hydraulic conductivity in soil with a rectangular holes

[MonsieurR]

Dear all,

I'm facing the problem of estimating the permeability or hydraulic conductivity of a gravelly soil with field "experiments" that are not standard. The experiments were as follow:
The watertable was 20 cm below the terrain
A rectangular hole was dug, with a depth of 1.4 m, and an area of 3.5m x 4.0m, roughly 17 m3 in volume below watertable.
The hole was drained with pumps and then it took 4 hrs to fill back with water.
No other data is given.

Is there an easy way of estimating the hydraulic conductivity of the soil with this data? I can't figure out how to find the hydraulic gradient and do the math.

Thanks in advance, best regards.

 

[fattdad]

take the square hole and determine it's area.
using that area, solve A=pi(r^2), which will return some equivalent value for,"r."

Use that value in the slug test equation, which uses the rate of recovery, the radius of the well (i.e., the equivalent radius you just calculated) and other such boundary conditions.

Don't worry about the practical matters of a square is not a circle! It's all within the practical limits of our practice.

In all honesty, I'da used the dewatering rate under constant drawdown to solve the well yield equations.

May find some value in the document, "Dewatering and Groundwater Control" (NAVFAC P-418, 1983).

f-d

ípapß gordo ainÆt no madre flaca!