Abstract

The paper considers the use of hydrological zones derived from runoff hydrographs as planning zones in a Nigerian river catchment. Altogether, 600 hydrographs were separated for 3 flows types for 11years on 20 selected sub basins. The 11 years data were obtained from the Hydrology Department of Kaduna State Water Board, Nigeria between 1979 and 1989. Hydrographs were separated by semi- logarithm method into 3 components of surface flow, interflow and groundwater flow. The Duncan test was used to find if differences exist in the composition and spatial pattern of annual hydrographs in the 20 sub basins of the study area. The results showed that significant differences exist not only in the composition of the different flow types but also from one basin to the other. On the whole, 6 regional patterns emerged for surface and groundwater runoff and 3 patterns for subsurface flow. These regional patterns were proposed as planning zones in the Upper Kaduna Catchment.

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