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Thesis (M. Sc.)--University of Hong Kong, 1998. / Includes bibliographical references.

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references.

Thesis (M.P.A.)--University of Hong Kong, 1999. / Includes bibliographical references. Also available in print.

Literature on subsurface drainage theories, determination of drainage parameters, and analysis approaches of uncertainty was reviewed. Sensitivity analysis was carried out on drain spacing equations for steady state and nonsteady state, in homogeneous soils and in layered soils. It was found that drain spacing is very sensitive to the hydraulic conductivity, the drainage coefficient, and the design midspan water table height. Spacing is not sensitive to the depth of the impermeable layer and the drain radius. In transient state, spacing is extremely sensitive to the midspan water table heights if the water table fall is relatively small. In that case steady state theory will yield more reliable results and its use is recommended. Drain spacing is usually more sensitive to the hydraulic conductivity of the soil below the drains than to that of the soil above the drains. Therefore, it is desirable to take samples from deeper soil when measuring hydraulic conductivity. A new spacing formula was developed for two-layered soils and a special case of three-layered soils with drains at the interface of the top two layers. This equation was compared with the Kirkham equation. The new formula yields spacings close to the Kirkham equation if the hydraulic conductivity of the soil above the drains is relatively small; otherwise, it tends to give more accurate results. First and second order analysis methods were employed to analyze parameter uncertainty in subsurface drainage design. It was found that conventional design methods based on a deterministic framework may result in inadequate spacing due to the uncertainty involved. Uncertainty may be incorporated into practical design by using the simple equations and graphs presented in this research; the procedure was illustrated through an example. Conclusions were drawn from the present study and recommendations were made for future research. / Applied Science, Faculty of / Graduate

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Lima’s Villa El Salvador is one of the cities of Peru with the highest population growth rate in recent decades, and still it is needing to develop many urban infrastructure services. However, this process of urbanization has also produced a decrease in the permeability of the terrain causing in recent years flooding and severe damages by the occurrence of heavy rains in the district. It was proposed the implementation of a sustainable urban drainage system (SUDS) to provide an engineering solution to this problem. It consists of a set of elements of the drainage network that will allow the collection, transport, retention, infiltration, and rainwater evacuation sustainably. Four SUDS alternatives were analyzed using well-founded methodologies to select the best alternative solution for the existing problem using technical, economic, and environmental criteria. The implementation of a retention tank and green ditches is the solution adopted to reduce the risk of flooding because of urbanization in the studied area. Runoff from the upper part of the basin will be collected through the green ditches, and the collected water will be distributed to increase the green spaces of the district. However, it will be necessary to supplement with irrigation to preserve them since this locality is climatologically arid. Successful storm water management requires integration with the urban and regional development plans.