Introduction

Streamflow is the combined result of all climatological and geographical factors that operate in a drainage basin . It is the only phase of the hydrological cycle in which the water is confined in well-defined channe ls which permit accurate measu remen t s to be made of the quanti t ies involved. O the r measu remen t s o f the hydrological cycle are point m e a s u r e m e n t s for which the uncer ta int ies , on an areal basis , are difficult, if not imposs ib le , to es t imate .