Hydrological studies of a laboratory catchment area under rainfall simulation

The principal objective of this research programme was to conduct a re-examination of the basic nature of hydrological parameters of rainfall, infiltration and surface runoff. Experimental work using a specially designed laboratory catchment and a rainfall simulator is described. This equipment is regarded as a useful contribution to the study of hydrology and its description is given in the early part of the thesis. Basically the equipment consists of a soil catchment area that can be precisely inclined to any desired angle. Additional instrumentation then monitors the flow of water across the surface of, and through the soil catchment bed. Precipitation is provided by another specially designed unit that simulates rainfall at a particular rate and distribution. It is demonstrated that this equipment is capable of realistically simulating the water flow as it would occur on a natural catchment. It provides means of studying hydrological phenomena for a range of soil samples under precise control. A large amount of data was collected on the basic of laboratory experiments for a range of soil samples. From these data it was possible to develop a number of empirical formulae that conveniently summarise the inter-relationships between the principal hydrological parameters, namely rain intensity, runoff, infiltration and catchment slope. Known physical laws of fluid flow have been used in the derivation of the formulae. Previous hydrological work is reviewed and, where appropriate, is compared with the present study. Suggestions for further work are also outlined