Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references.

Drainable porosity as a function of water table was investigated to replace the common practice of treating it as a constant A continuous function in the form of a negative exponential equation relating drainable porosity to water table depth was developed by three methods: (1) laboratory core-sample analysis; (2) rainfall rate and water table depth analysis; (3) drainage rate and water table depth analysis. Furthermore, this function was derived for four different water table regimes: (1) subsurface drainage; (2) low subirrigation and subsurface drainage; (3) high subirrigation and subsurface drainage; (4) no drainage and no subirrigation. The drainable porosity function was incorporated into a water balance model which simulated the soil moisture profile and the water table depth on a daily basis. Major modification of the previous model was the elimination of separate falling and rising water table equations since discrete porosity values were no longer assigned to particular soil depth intervals. A subroutine program which computed the total maximum transient storage and the transient storages to each of the four successive soil zones was also incorporated. The 'maximum drainable porosity' and the 'rate constant' parameters in the negative exponential equation were found to be different among the three methods of analysis and among the four water table regimes. Good agreement between simulated and actual water table depths of each regime for 1984 and 1985 was found. The modified water balance model could be used to generate different water table depths by changing the input parameter of design drainage rate. From these outputs, a appropriate drainage rate which gives the desired water table depth could be selected for the purpose of horizontal subsurface drainage system design. / Applied Science, Faculty of / Graduate

Thesis (M.Sc.) - Simon Fraser University, 2005. / Theses (Dept. of Earth Sciences) / Simon Fraser University.

Thesis (M.Sc.) - Simon Fraser University, 2005. / Theses (Dept. of Earth Sciences) / Simon Fraser University.

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. Title from title screen (viewed Mar. 21, 2007). Includes bibliographical references (leaves 162-165). Online version of the print original.

The highly nonlinear nature of unsaturated flow results in different ways to approximate the delayed or instantaneous movement of the water table. In nearly all the approaches, the water table is conceptually treated as a “material surface”. This term defines the water table as having two simultaneous properties: 1) the pressure along the surface is atmospheric pressure, and 2) the water table is fixed to the material, i.e., a set of water particles. This article makes an attempt to explain that the water table, defined as the surface at atmospheric pressure, is not a material boundary, and the water table can move independent of the water particles. Velocity of the water table and velocity of drainage are compared with three analytical models: the Neuman model, which assumes instantaneous drainage from the unsaturated zone; the Moench model, which considered gradual drainage from the unsaturated zone using a series of exponential terms in the water table boundary condition; and the Mathias-Butler model, which obtained a new drainage function based on a linearized Richard’s equation but limited the variation of soil moisture and hydraulic conductivity in the unsaturated zone to exponential functions. Numerical analysis was conducted with VS2DT and both the numerical and the analytical results were compared with a 7-day, constant rate pumping test conducted by University of Waterloo researchers at Canadian Air Force Base Borden in Ontario, Canada.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona, 1988. / Includes bibliographical references (leaves 183-185).

Thesis (M.S.)--University of South Florida, 2002. / Title from PDF of title page. Document formatted into pages; contains 120 pages. Includes bibliographical references (p. 102-107).

Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. Includes bibliographical references (leaves 162-165).

Thesis (M.Sc.Eng.)-University of Natal, Durban, 1973. / Full text also available online. Scroll down to electronic link.