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Item Open Access An evaluation of the effects of climate change on flood frequency in the Luvuvhu River Catchment, Limpopo Province, South Africa(WIT Press, 2014) Kundu, P. M.; Singo, R. L.; Odiyo, J. O.; Nkuna, R. N.Climate change poses a great risk to natural resources and agriculture in the Luvuvhu River Catchment. The catchment has experienced floods resulting from higher than normal rainfall associated with the Intertropical Convergence Zone and cyclones, which have caused enormous damage to property and impacted negatively on fauna and flora and human livelihoods. In order to understand the dynamics involved in the effects of climate change in the catchment, annual maximum flow data was used to evaluate flood frequencies. The distribution models used in the study included the Generalized Extreme Value distributions, the Gumbel Extreme Value type I distribution, the Log-normal distribution and the Log Pearson type III distribution. The extreme value analysis showed that the Log-normal and Log-Pearson type III distributions provided the best fit, which could be used to derive the probability of occurrence of flood events. The results showed a general increase in the frequency of extreme events, accompanied by floods of higher magnitude.Item Open Access Flood Frequency Analysis of Annual Maximum Stream Flows for Luvuvhu River Catchment, Limpopo Province, South Africa(2012) Singo, L. R.; Kundu, P. M.; Odiyo, J. O.; Mathivha, F. I.; Nkuna, T. R.Luvuvhu River Catchment (LRC) is one of the regions in South Africa where floods have caused enormous damage and impacted negatively on fauna and flora. Over the years, the catchment has experienced floods resulting from heavy rainfall associated with the ITCZ. Annual maximum flow data from 8 stations with 50 years hydrological data were used to analyze flood frequencies in the catchment. To derive the probability of occurrence of flood events, the frequency distributions which could best describe the past characteristics and magnitudes of such floods were tested. This involved the determination of the best flood frequency models, which could be fitted to the available historical recorded data. The distribution models used included the Generalized Extreme Value, Gumbel or Extreme Value type 1, Log-Normal and the Log Pearson type III distributions. The extreme value analysis showed that the Gumbel and Log Pearson type III distributions provided the best fit.Item Open Access Impact of land use change on surface runoff and stream discharges in Luvuvhu River Catchment(2016) Singo, L. R.; Kundu, P. M.; Odiyo, J. O.Luvuvhu River catchment in Limpopo Province of South Africa experiences floods resulting from heavy rainfall of intensities exceeding 15 mm per hour associated with the Intertropical Convergence Zone. The generation of runoff is triggered by the rainfall intensity and soil moisture status. Runoff was calculated as a product of the net precipitation and a curve number coefficient. It was then routed using the Muskingum-Cunge method through the basin along flow paths determined by the topography using a diffusive wave transfer model that enabled the calculation of response functions between start and end point, depending upon slope, flow velocity and dissipation characteristics along the flow lines. Results showed that the simulated discharges closely compared with the measured discharges without the need for model optimization. It was concluded that simulation techniques had the potential to determine the influence of changes in land use to the hydrologic response of the catchment.Item Open Access Spatial variation of reference evapotranspiration and its influence on the hydrology of Luvuvhu River Catchment(2016-07) Singo, L. R.; Kundu, P. M.; Mathivha, F. I.This study estimated spatial variation of reference evapotranspiration (ETo) and its influence on the hydrology of Luvuvhu River Catchment.The ETo plays a key role in irrigation systems design, water resource management under irrigated and rainfed production.Simulation of ETo was performed using the Penman-Monteith method in CROPWAT 8.0 software. Results showed the spatial and temporal distribution of ETo with peaks in summer months. Areas with higher ETo values were near rivers and streams, which generally have more abundant vegetation. Areas with low ETo values were relatively dry, where pasture and grasslands dominated the landscape. Correlation results showed that no relationship exists between streamflow and ETo (r = 0.36) in the study area, hence, a significant relationship exists between rainfall and ETo (r = 0.86). The study recommends the use ofCROPWATmodel for computing ETo under arid and semi-arid climatic conditions for water resource management and planning.