Author : Maged H. Hussein

Egyptian Vertisols have high productivity and have a moderate to high fertility. It has a very high water-holding capacity, but most of the water is tightly bound and not available to plants. Vertisols are heavy clay soils that show significant expansion and contraction due to the presence or absence of moisture. Deep and wide cracks in a polygonal pattern are formed as a result of this process. Most Egyptian Vertisols areas have poor productivity due to salt affected soils and waterlogging. Water management in such lands needs much attention. An understanding of the hydraulic properties of heavy clay soils is obviously of importance in assessing their potential for reclamation. The objective of this paper is to take into consideration the effect of top cracking layer on the conveyance of water to the drains in heavy clay soil. The unsteady state equation for design spacing between subsurface field drains is developed for use in cracking Vertisols. Compared with the Glover-Dumm equation, the new equation calculates wider spacing ranged between 38% and 54% for different hydraulic conductivity values varied between 0.10 and 0.50 m/day.

Keywords: Drainage, Design, Vertisols, Cracks.

Article published in International Journal of Current Engineering and Technology, Vol.5, No.4 (Aug-2015)