Click on “Download PDF” for the PDF version or on the title for the HTML version.
If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.
Empty Drain and the Water Level at Midway between the Drains. Aspects Regarding Management
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.orgCitation: 9th International Drainage Symposium held jointly with CIGR and CSBE/SCGAB Proceedings, 13-16 June 2010 IDS-CSBE-101372.(doi:10.13031/2013.32180)
Authors: Paulo Jorge Castanheira
Keywords: Drainage, Controlled Drainage, Numerical Simulation
Standing water above drains as a result of a submerged drain outlet, promotes flow conditions so that there is a smaller rise in the water table height at midway between the drains. This case has been studied through theoretical analyses by van Deemter (1950); Childs (1958), Kirkham(1958); Santos-Jnior (1971); Wessseling (1979) an Gammal et al (1995). In this paper the numerical results from DRENAFEM software package simulator are compared with the theoretical analysis of Santos-Jnior (1971). The software uses a finite element analysis to solve the Richards equation. Several simulations were performed with a small drain radius, and with a back pressure in the drain outlet to achieve a high entrance resistance and promote the rise of the water table at midway between the drains. With the standing water above the drains, the theoretical and numerical results show a rise in the water table height which is smaller than the drain outlet pressure. This paper demonstrates how the software can be used to simulate the behavior of a water table under controlled drainage to determine the water tables position in situations with no analytical solutions, such as hydraulic conductivity anisotropy or in non-homogeneous soils with several layers.(Download PDF) (Export to EndNotes)