Uncertainties in Flow-Duration-Frequency Relationships of High and Low Flow Extremes in Lake Victoria Basin
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Date
2013
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Publisher
Water
Abstract
This paper focuses on uncertainty analysis to aid decision making in
applications of statistically modeled flow-duration-frequency (FDF) relationships of both
daily high and low flows. The analysis is based on 24 selected catchments in the Lake
Victoria basin in Eastern Africa. The FDF relationships were derived for aggregation levels
in the range 1–90 days for high flows and 1–365 days for low flows. The validity of the
projected FDF quantiles for high return periods T was checked using growth factor curves.
Monte Carlo simulations were used to construct confidence intervals CI on both the
estimated Ts for given flows and the estimated FDF quantiles for given T. The average bias
of the modeled T of high and low flows are for all catchments and Ts up to 25 years lower
than 8%. Despite this relatively small average bias in the modeled T, the limits of the CI on
the modeled 25-year flows go up to more than 100% for high flows and more than 150%
for low flows. The assessed FDF relationships and accompanied uncertainties are useful
for various types of risk based water engineering and water management applications
related to floods and droughts.
Description
Keywords
Floods, High flows, Hydrological extremes, Lake Victoria basin, Low flows, Uncertainty analysis, Flow-duration-frequency (FDF)
Citation
Onyutha, C., & Willems, P. (2013). Uncertainties in flow-duration-frequency relationships of high and low flow extremes in Lake Victoria basin. Water , 5 (4), 1561-1579. doi:10.3390/w5041561