Reed, D.W. 1976. Deterministic modelling of catchment systems. PhD thesis, Engineering Mathematics, University of Newcastle upon Tyne, 248 pp.
The main theme of the thesis is flood event modelling of gauged catchments. Much of the work presented is based on unit hydrograph theory, i.e. a lumped linear time-invariant representation of the rainfall excess/direct run-off subsystem. However attention is given also to non-linear effects.
Separation techniques are examined closely. Particular emphasis is placed on the application of rainfall separation methods based on "infiltration equations".
Consideration is given to both analysis and synthesis techniques of unit hydrograph derivation. In the analysis approach a discrete formulation of the convolution relation is advocated, the resulting system of equations being solved by least-squares inversion. An important section discusses the adverse effect on the inversion process of uncertainties in the data, and means by which the derivation of a satisfactory unit hydrograph can be assured.
In the synthesis approach fitting methods and parametric forms are compared and contrasted from a number of viewpoints. Attention is drawn to an essential imcompatability of infinite-tailed response functions and traditional methods of run-off separation. This leads to discussion of an alternative concept of run-off separation, "cause-effect" separation. The effect of non-synchronization in the rainfall and run-off records is also investigated.
Details arc presented of a rainfall/run-off model based on unit hydrograph theory and simple separation techniques. Its application to two catchments is fully documented.
Subsequent chapters deal with catchment non-linearity, in particular variable lag effects. Included in the final chapter is a recommended strategy for flood event modelling.