| Author | Jayaveerasingam, Milroy Lakshman |
| Call Number | AIT Thesis no.WA-90-13 |
| Subject(s) | Seepage
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Four simple yet physically based one-dimensional infiltration models (Green-Ampt, Phillip's and Parlange, and Morel-Seytoux) were examined for predicting the infiltration process of homogeneous soils at uniform initial moisture contents subjected to both steady and unsteady rainfall input. The performance of these models were evaluated from experiments comprising combinations of five major soil types, sand, sandy loam, loam, silt loam and silt loam (Welling), two types of initial moisture contents (at wilting point and at field capacity), a variety of uniform rainfalls at intensities which are multiples of the saturated hydraulic conductivities of soils, and unsteady rainfalls designed from three rainfall patterns. The soil hydrologic properties used were based on the soil parameters of Brooks and Corey's equation extensively documented by Brakensiek, Engleman and Saxton (1982) for 1323 Soil samples with about 5350 horizons across United states.
The models were tested against the numerical solutions of the one dimensional Richard's equation. The Green-Ampt model predicted cumulative infiltrations accurately for pervious soils but relatively poorly for impervious soils. Philip's model predicted accurately for sand and swelling silt loam when the gravity term A equal to K but when A was equal to 2K/3 it only did well for sandy loam, loam and silt loam. The versions of Smith and Parlanges models with K(0) varying rapidly near saturation generally predicted the cumulative infiltration well when steady rains were applied on sand, sandy loam and loam. For the other version with K(0) varying slowly near saturation (S), the model did well for silt loam. But both versions failed when the applied rain pulse was abruptly changed to a bigger burst at a time close to ponding.
The Morel-Seytoux model, which includes the viscous effects of air, predicted well for sandy loam and loam soils when steady rains were applied, but failed to predict the time to ponding for rainfall intensities that were of the order K/B.
The accuracy of transient infiltration estimated by these approximate analytical infiltration models depend on a combination of governing factors as mentioned. |
| Year | 1990 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Resources Research Engineering (WA) |
| Chairperson(s) | Gan, Thian Yew |
| Examination Committee(s) | Eggers, Helmut ;Loof, Rainer
|
| Scholarship Donor(s) | DAAD |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |