Stream Ordering As a Tool For Effective River Basin Development: Examples From Komadugu –Yobe River Basin, Nigeria

Abstract

This study assessed the existing structure/delineation of the areas of coverage of the River Basin Development Authorities (RBDAs) in Nigeria using RBDAs sharing the largest inland drainage system, Komadugu – Yobe River System, covering Hadeja Jama’are River Basin Development Authority and Chad Basin Development Authority. The main aim is to identify structural defects if any, and show the resulting operational challenges that the defects posed to development of the Komadu – Yobe Basin area. Stream Ordering method was used as a theoretical framework to assess the delineation of the areas of jurisdiction of the RBDAs. Data was obtained from downloaded satellite images of the Basin Areas, using ArcGIS version 10.0 and Erdas Imagine 9.2 software, as well as information from topographic and hydrological maps of the study area. The analyses showed that the delineation of the RBDAs in Nigeria was neither based on the hydrological regions of the country nor on the basis of the principles of stream ordering for integrated development in River Basin Areas. Secondary data were also used to gather information on the impact of RBDAs operations on the River Basin Areas. The results further revealed many operational challenges such as poor coordination in water resource utilization, water loss, loss in production, loss of local dry season shadoof farming opportunities and worsening conditions of living of farmers at project sites and fishermen in downstream areas. It is established that application of stream ordering in a nested hierarchy of sizes as demonstrated on the Komadugu – Yobe river system covering the basin areas of rivers Hadeija, Chalawa and jama’are serves as guide for overcoming the structural/operational challenges and improve the RBDAs performance in realizing their set objectives. It is recommended that the existing 12 RBDAs structure be collapsed into the 8 Hydrological Zones in the country, and project implementation takes into account the principles of stream ordering for effective performance.

Key Words: River Basin, River Basin Development, Stream Ordering, River Komadugu-Yobe Basin, operational challenges.