Modelling seepage and percolation in low land paddy fields | |
| Author | Alam, Jahangir |
| Call Number | AIT Thesis no.AE-90-52 |
| Subject(s) | Seepage--Mathematical models Percolation Irrigation farming |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Rice is normally grown by ponding water to maintain better growth . In such situates , where free flooding is the most common practice , a large amount of irrigation water is lost from the paddy fields into surrounding fields through the ridges(bunds). A sizable part of t h e capital investment in every irrigation project goes a s waste in the for m of seepage water. Therefore , the magnitude of the both lateral loss known as seepage and vertical loss known as percolation are to be accurately determined for better management of irrigation . In t h is study an attempt was made to determine the magnitude of seepage and percolation separately in different paddy field condition with variable water table, and ponding water depths for different soil textures containing different soil layer with different hydraulic conductivities. For these purpose , the two dimensional steady flow equation converted into finite difference expression and the solution was obtained by relaxation technique. A compute r program was dev e lope d to compute the new pressure heads by t he process of iteration. See page and percolation were calculated from the n ew pressure head s by applying the Darcy ' slaw. The computer solutions were applied to several hypothetical field situations for the purpose of analysis. It was observed that seepage a nd percolation increased with deeper water table and higher ponding depth. Evaporation from the bund surface increases with increase in ponding water depth. As the ponding depth increased, the area of the bund exposed to the atmosphere through which evaporation took p lace was reduced , but the suction at the surface nodes of the bund decreased because of the higher amount of water retained at the surface layer of the bund . |
| Year | 1990 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Murty, V.V.N ;Goto, Akira |
| Examination Committee(s) | Nielsen, Jens Moller |
| Scholarship Donor(s) | German Academic Exchange Service (DAAD) |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |