Engineering Geological Studies of Small/Mini/Micro Hydropower Sites (A Case Study in Anger and Guder Sub-basins)
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Date
2007-07
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Addis Ababa Universty
Abstract
Ethiopia is endowed with huge amount of renewable energy resources
such as small-hydro that is identified to be suitable for rural
electrification. This study takes the case of potential small hydropower
assessment in Anger and Guder sub-basins of Abbay Basin. The study
indicates that there are many small hydropower potential sites in the
study area. Various researchers identified potential small hydropower
sites in the different regions of the country. Unfortunately, random
selection of sites as considered by other researchers may end up
identifying a site which will not give reliable amount of discharge for
power generation through out the year. In this study, a new attempt is
tried to produce initial site identification criteria by considering various
parameters which will affect the power out put of a site. The initial
identification criteria set up specifically suitable for the study area is
found to be a minimum of 110 km2 catchment area and 80 m head. A
total of 18 potential sites are identified in the present study by
considering this criterion with a total power potential of 19564 kw. In
addition an attempt is also made to develop regionalized flow-duration
curves for prediction of discharge at ungauged streams. To do this,
methods have been involved in developing a set of parametric flowduration
curves based on flow values at gauged points. This data set
includes the correlation of drainage area versus average annual run off
for all gauges in the region and values of Q for a particular exceedance
values. This method allows prediction of only certain exceedance values
of discharge for potential sites.
For the present study, engineering geological mapping was carried out
along the different components of the sites in the context of high
lightening possible problems that could be caused from the earth
materials present around each ground verified SHP sites. In an effort to incorporate these factors, the strength and weathering characteristics of
rocks, swelling potential of soils and the stability conditions of rock and
soil slopes exposed along the different components of the SHP schemes
were evaluated by utilizing various empirical and index properties of
soils. Therefore, further research is recommended for the assessment
small hydropower sites which consider a combination of more elaborate
hydrologic and geotechnical aspects.
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Keywords
Small/Mini/Micro Hydropower Sites