International Workshop CC

Mario Lunghi's search for a slide rule

“Soil infiltration capacity”

HC\ (m/s)\ =\ \frac{(Volume)}{(T\ \pi\ R^2)}\ Rt
Rt = 2.2902\ \ast\ \left(\frac{{0.9842}^{Temp}}{{Temp}^{0.102}}\right)

Data:

Complete description of the soil infiltration capacity problem (Mario Lunghi)
  • In alluvial and loose soils, rainwater is usually infiltrated into the soil through concrete “draining pits”
  • The design of these pits is based on soil permeability tests performed on the field (aka “percolation tests”), where some water volume is let to be drained into the soil recording the elapsed time.
  • In order to correctly assess the actual value about vertical soil permeability (which is the main parameter leading to draining pit size and depth) you have to perform some sort of field tests.
  • Soil hydraulic conductivity HC (in m/s) is calculated from:
    Volume = infiltrated water volume for a given drawdown step (in cubic meters)
    T = elapsed time (in seconds)
    R = test tube inner radius (in meters, usually 0.148 m)
    Rt = temperature correction factor, using:
    Temp = water temperature (in °C)

Question:

  1. Are there special slide rules for soil hydraulic conductivity (permeability) calculations?