Hydraulic function of subsurface pipe drainage system on agricultural and drainage experimental field in Mashtul pilot area (Nile Delta, Egypt)

The objective of this article is to explain the hydraulic function of subsurface pipe drainage system on agricultural experimental field in Mashtul Pilot Area (Nile Delta) in non-steady state drainage flow conditions. Subsurface drainage structures were designed for the conditions of steady state drainage flow. However, in reality non-steady state drainage situations prevail. A model to solve the problem is presented. Boussinesq's equation was used to study the non-steady state drainage flow. The final expression of lowering of water table in time was approximated by Glover-Dumm.