Towards effective Hydrological Measurements downstream of Oyan dam

Olatunji T.
National Water Resources Institute, PMB 2309, Kaduna, Nigeria.

Abstract

In 2011 the National Water Resources Institute (NWRI), Kaduna developed a Concept Note on Reservoir
Sedimentation Study for Bakolori, Goronyo and Oyan dams. The study thrust is in five areas: Reservoir depth
sounding, Downstream Studies, Hydrological Studies, Remote Sensing/GIS Applications and Environmental/
Socio-economic impacts assessments. A focus group on each area of the Reservoir Sedimentation study was
constituted. NWRI held collaborative meetings with participating staff of selected organizations in Nigeria that
are to implement the study. NWRI Management had undertaken a planning visit to these dams and the
supports of the River Basin organizations that own the dams was secured. On 24th
– 27th. May, 2011, the
author participated in the Downstream Study group planning visit to Oyan Dam. During the visit, the
downstream study group had a meeting with the Management of the Ogun-Oshun River Basin Development
Authority (OORBDA) to discuss the study and obtain relevant documents like rating curves of existing gauging
stations, maps etc. Also there was a visit to Oyan Dam reservoir, the GPS readings of benchmarks at the dam
site were taken and the Oyan river system downstream of the dam was explored to determine along the main
channel suitable sections for discharge measurement and Sediment sampling for onsite determination of
sediment concentrations. Ten sites on the Oyan and Ogun rivers system were visited noting their hydroenvironmental
peculiarities. A brief overview of some of the sites is highlighted in the paper. Five locations
were identified as suitable for discharge measurement and sediment sampling.

Key words: Oyan dam reservoir, Downstream, Flooding, Gauging Stations, Stage- discharge.

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