Determining operating rules for the Letaba river system in South Africa using three models

Nyabeze, Washington R.; Mallory, S. J. L.; Hallowes, Jason; Mwaka, B.; Sinha, Pammi

doi:10.1016/j.pce.2007.07.003

Cited by 3 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The catchments are characterised by low rainfall and high potential evaporation figures of 400 -600 mm and 2 100 -2 200 mm per annum respectively (Nyabeze et al, 2007). (Dippenaar et al 2010).…”

Section: Study Areamentioning

confidence: 99%

Aquifer vulnerability using recharge, depth to groundwater, soil type and slope to classify the vadose zone (Molototsi and Middle Letaba quaternary catchments, Limpopo Province, South Africa)

Makonto

Dippenaar

2014

Environ Earth Sci

View full text Add to dashboard Cite

The aquifer vulnerability of the Molototsi (B81G) and Middle Letaba (B82D) quaternary catchments was assessed to determine the influence of the vadose zone on the groundwater regime. The aquifer vulnerability was assessed by developing a new method, which evaluates the vadose zone as a pathway for pollutants by using the following four parameters: Recharge, Depth to water table, Soil type (saturated vertical hydraulic conductivity) and Slope (RDSS). Recharge was estimated using the Chloride-mass balance method and the depth to the water table was measured in the field using dipmeter. The seepage behaviour (soil type) was determined as hydraulic conductivity from in-situ infiltration and percolation testing (SABS 0252-2:1993 and double ring infiltrometer). The slopes were determined with the digital elevation method using ArcGIS software. The four parameters were overlaid using Weighted Sum, Weighted Overlay and Raster Calculator to produce the vulnerability map. Different weightings were attributed in the methods and the best selected. The results obtained indicated high vulnerability on the lower and upper parts of both catchments. The benefits of the method described are (a) the easy quantification of the parameters through fairly simple methods and (b) the exclusion of arbitrary index values.

show abstract

Section: Study Areamentioning

confidence: 99%

Aquifer vulnerability using recharge, depth to groundwater, soil type and slope to classify the vadose zone (Molototsi and Middle Letaba quaternary catchments, Limpopo Province, South Africa)

Makonto

Dippenaar

2014

Environ Earth Sci

View full text Add to dashboard Cite

show abstract

“…The WRYM and WRPM apply stochastically generated stream flow sequences for operational analysis (Nyabeze et al, 2007). Moreover, the water research commission (WRC, 2004) monthly stochastic stream flow model for South Africa (STOMSA) has been used to generate coefficients for stochastic stream flow.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the water research commission (WRC, 2004) monthly stochastic stream flow model for South Africa (STOMSA) has been used to generate coefficients for stochastic stream flow. The generated coefficients in STOMSA subsequently are used as input to the WRYM/WRPM models (Nyabeze et al, 2007). Unfortunately these models Journal of Geoscience and Environment Protection are not capable of comprehensively modelling stochastic river/stream flow to provide conclusive results on the best model to be selected.…”

Section: Introductionmentioning

confidence: 99%

Stochastic Modelling of Great Letaba River Flow Process

Kifanyi¹,

Ndambuki²,

Odai³

et al. 2019

GEP

View full text Add to dashboard Cite

A stochastic approach is presented in view that a time series modelling is achieved through an Autoregressive Moving Average (ARMA) model. The applicability of the ARMA model is then further presented using the Great Letaba River as a case study. River flow discharge for 25 years (1989-2014) for the Great Letaba River was obtained from the Department of Water and Sanitation, South Africa and analysed by Autoregressive (AR), Autoregressive Moving Average (ARMA) and Autoregressive Integrated Moving Average (ARIMA) models. Monte Carlo simulation approach was used to generate forecasts of the ARIMA error model for the next 25 years. Initial model identification was done using the Autocorrelation function (ACF) and Partial Autocorrelation function (PACF). The model analysis and evaluations provided proper predictions of the river system. The models revealed some degree of correlation and seasonality behaviour with decreasing river flow. Hence, in conclusion, the Great Letaba River flow has shown a decreasing trend and therefore, should be effectively used for sustainable future development.

show abstract

Yield-reliability analysis and operating rules for run-of-river abstractions for typical rural water supply: Siloam Village case study

Odiyo¹,

Makungo²,

Ndiritu³

et al. 2015

WSA

View full text Add to dashboard Cite

The study focused on yield-reliability analysis and operating rules for optimum scheduling of run-of-river (ROR) abstractions for typical rural water supply schemes using Siloam Village, Limpopo Province, South Africa, as a case study. Efficient operation of water supply systems requires operating rules as decision support tools. System operation methods have hardly been developed or applied to water supply to rural communities that depend on ROR abstractions. Simulated runoff was used to derive unregulated river yield at different levels of assurance of supply (LAS) for Nzhelele River at Siloam Village using 1-day flow duration curves. Yield-reliability analysis results were used to derive operating rules. The results show that Nzhelele River can meet domestic and low-flow requirements at 50-80% (1:2-1:5) LAS. The low-flow and domestic water requirements can be partially met at 90% (1:10) LAS. The generic operating rules for ROR abstractions were consequently derived from the procedure used in developing operating rules for Nzhelele River. This enables generation of operating rules for ROR abstractions in any typical rural water supply system.

show abstract

Determining operating rules for the Letaba river system in South Africa using three models

Cited by 3 publications

References 4 publications

Aquifer vulnerability using recharge, depth to groundwater, soil type and slope to classify the vadose zone (Molototsi and Middle Letaba quaternary catchments, Limpopo Province, South Africa)

Aquifer vulnerability using recharge, depth to groundwater, soil type and slope to classify the vadose zone (Molototsi and Middle Letaba quaternary catchments, Limpopo Province, South Africa)

Stochastic Modelling of Great Letaba River Flow Process

Yield-reliability analysis and operating rules for run-of-river abstractions for typical rural water supply: Siloam Village case study

Contact Info

Product

Resources

About