scholarly journals Verification of runoff volume, peak discharge and sediment yield simulated using the ACRU model for bare fallow and sugarcane fields

Water SA ◽  
2020 ◽  
Vol 46 (2 April) ◽  
Author(s):  
Daniel Otim ◽  
Jeff Smithers ◽  
Aidan Senzanje ◽  
Rianto van Antwerpen
Keyword(s):  
South Africa ◽  
Sediment Yield ◽  
Management Practices ◽  
Primary Objective ◽  
Model Verification ◽  
Peak Discharge ◽  
Time Step ◽  
Sugarcane Production ◽  
Runoff Volume ◽  
Bare Fallow

The Agricultural Catchments Research Unit (ACRU) model is a daily time step physical-conceptual agrohydrological model with various applications, design hydrology being one of them. Model verification is a measure of model performance and streamflow, soil water content and sediment yield simulated by the ACRU model have been extensively verified against observed data in southern Africa and internationally. The primary objective of this study was to verify simulated runoff volume, peak discharge and sediment yield against observed data from small catchments, under both bare fallow conditions and sugarcane production, which were located at La Mercy in South Africa. The study area comprised 4 research catchments, 101, 102, 103 and 104, monitored both under bare fallow conditions and sugarcane production, with different management practices per catchment.  Observed data comprised: daily rainfall, maximum and minimum temperature, A-pan evaporation and runoff for the period 1978–1995, and peak discharge and sediment yield for the period 1984–1995. The data were checked for errors and and inconsistent records excluded from analysis. Runoff volume, peak discharge and sediment yield were simulated with the ACRU model and verified against the respective observed data. In general, the correlations between observed and simulated daily runoff volumes and peak discharge were acceptable (i.e. slopes of regression lines close to unity, R2 ≥ 0.6 and the Nash–Sutcliffe coefficient of efficiency close to unity). Similarly, the correlation between observed and simulated sediment yield was also good. From the results obtained, it is concluded that the ACRU model is suitable for the simulation of runoff volume, peak discharge and sediment yield from catchments under both bare fallow and sugarcane land cover in South Africa.

scholarly journals Verification of runoff volume, peak discharge and sediment yield simulated using the ACRU model for bare fallow and sugarcane fields

Water SA ◽  
2020 ◽  
Vol 46 (2 April) ◽  
Author(s):  
Daniel Otim ◽  
Jeff Smithers ◽  
Aidan Senzanje ◽  
Rianto van Antwerpen
Keyword(s):  
South Africa ◽  
Sediment Yield ◽  
Management Practices ◽  
Primary Objective ◽  
Model Verification ◽  
Peak Discharge ◽  
Time Step ◽  
Sugarcane Production ◽  
Runoff Volume ◽  
Bare Fallow

The Agricultural Catchments Research Unit (ACRU) model is a daily time step physical-conceptual agrohydrological model with various applications, design hydrology being one of them. Model verification is a measure of model performance and streamflow, soil water content and sediment yield simulated by the ACRU model have been extensively verified against observed data in southern Africa and internationally. The primary objective of this study was to verify simulated runoff volume, peak discharge and sediment yield against observed data from small catchments, under both bare fallow conditions and sugarcane production, which were located at La Mercy in South Africa. The study area comprised 4 research catchments, 101, 102, 103 and 104, monitored both under bare fallow conditions and sugarcane production, with different management practices per catchment.  Observed data comprised: daily rainfall, maximum and minimum temperature, A-pan evaporation and runoff for the period 1978–1995, and peak discharge and sediment yield for the period 1984–1995. The data were checked for errors and and inconsistent records excluded from analysis. Runoff volume, peak discharge and sediment yield were simulated with the ACRU model and verified against the respective observed data. In general, the correlations between observed and simulated daily runoff volumes and peak discharge were acceptable (i.e. slopes of regression lines close to unity, R2 ≥ 0.6 and the Nash–Sutcliffe coefficient of efficiency close to unity). Similarly, the correlation between observed and simulated sediment yield was also good. From the results obtained, it is concluded that the ACRU model is suitable for the simulation of runoff volume, peak discharge and sediment yield from catchments under both bare fallow and sugarcane land cover in South Africa.

scholarly journals Development and assessment of rules to parameterise the ACRU model for design flood estimation

Water SA ◽  
2018 ◽  
Vol 44 (1 January) ◽  
Author(s):  
JC Smithers ◽  
TJ Rowe ◽  
MJC Horan ◽  
RE Schulze
Keyword(s):  
South Africa ◽  
Land Cover ◽  
Land Management ◽  
Management Practices ◽  
Peak Discharge ◽  
Future Research ◽  
Design Flood ◽  
Time Step ◽  
Hydrological Condition ◽  
Flood Estimation

Design flood estimation (DFE) is essential in the planning and design of hydraulic structures. In South Africa, outdated methods are widely applied for DFE. In this paper the potential of a continuous simulation modelling (CSM) approach to DFE in South Africa, using the daily time-step ACRU agrohydrological model, is investigated. The paper focuses on the links and similarities between the SCS-SA and ACRU models and the subsequent preliminary investigations that were undertaken to account for and incorporate the land cover classes, including land management practices and hydrological condition, of the SCS-SA model into the ACRU CSM approach. The approach to this study was to investigate how design volumes simulated by the SCS-SA model for various land management practices or conditions could be simulated by the ACRU model. Since peak discharge estimation in both models is directly dependent on simulated volumes, this preliminary study focused only on design runoff volumes, with subsequent investigations on peak discharge required in future research. In the absence of observed data, design runoff volumes and changes in design runoff volumes, as simulated by the SCS-SA model, were used as a substitute for observed data, i.e., as a reference, to achieve similar design runoff volumes and changes in design volumes in the ACRU model. This was achieved by adjusting relevant input parameters in the ACRU model to represent the change in management practice or hydrological condition, as represented in the SCS-SA model. Following a sensitivity analysis of relevant ACRU parameters, calibration of 2 selected parameters against SCS-SA CN values for selected land cover classes was performed. A strong linear relationship (R2 = 0.94) between these ACRU parameters and SCS-SA CNs for selected land cover classes was found and consequently specific rules and equations were developed to represent SCS-SA land cover classes in ACRU. Recommendations are made to further validate and verify the approach and to further the development of a CSM system for DFE in South Africa.

Optimal Ecological Management Practices for Controlling Sediment Yield and Peak Discharge from Hilly Urban Areas

2015 ◽  
Vol 20 (10) ◽  
pp. 04015005 ◽  
Author(s):  
Banasri Sarma ◽  
Arup Kumar Sarma ◽  
Chandan Mahanta ◽  
V. P. Singh
Keyword(s):  
Sediment Yield ◽  
Urban Areas ◽  
Management Practices ◽  
Peak Discharge ◽  
Ecological Management

scholarly journals Factors Affecting Sugarcane Production by Small-Scale Growers in Ndwedwe Local Unicipality, South Africa

Agriculture ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 170
Author(s):  
Nkosingiphile Samuel Zulu ◽  
Melusi Sibanda ◽  
Bokang Stephen Tlali
Keyword(s):  
South Africa ◽  
Production Function ◽  
Optimal Allocation ◽  
Ordinary Least Squares ◽  
Primary Objective ◽  
Small Scale ◽  
Factors Affecting ◽  
Sugarcane Production ◽  
Clear Cut ◽  
The Government

Sugarcane is an important crop worldwide due to its many nutritional and economic uses. Small-scale sugarcane growers (SSGs) are a significant sector of sugarcane production in South Africa. However, the number of SSGs is noted to have declined from as early as the 2000s to the present time. As a result of the declining sugarcane production, there are now generally fewer SSGs. However, it is not clear cut as to what caused the decrease in sugarcane production by SSGs. The primary objective of this paper is to determine the factors affecting the sugarcane production by SSGs in Mona and Sonkombo in Ndwedwe Local Municipality. Data collection was through a well-structured questionnaire administered to 100 SSGs (that is, 50 respondents each from the study sites, namely Mona and Sonkombo) that were randomly selected. The paper employs descriptive statistics to describe farm characteristics, and a production function (Cobb–Douglass production function (CDPF)) analysis using the ordinary least squares (OLS) criterion to estimate the parameters affecting sugarcane production. Results show that late harvesting (by up to three (3) weeks), late fertiliser application (by up to six (6) months, and chemicals (Gramoxone) application (by up to five (5) months) were primary challenges facing SSGs, likely to result in declining sugarcane yield. The CDPF regression analysis reveals that significant predictors of the production function are: labour and the amount of chemicals (Gramoxone) applied. Labour (man-days/ha), amount of chemicals (Gramoxone) applied are found to be statistically significant and positively correlated with sugarcane production. The government, through the relevant Department of Agriculture, including the private sector, should intensify out-grower technical services for SSGs to realise higher production per hectare. Such services would ensure optimal allocation and application of inputs, labour and chemicals (herbicides and pesticides), respectively, at the right time to ensure efficacy. There is also a need to introduce buying consortiums for SSGs to reduce the costs of inputs.

scholarly journals Analysis of a Flash Flood in a Small Basin in Crete

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2253 ◽  
Author(s):  
Sofia Sarchani ◽  
Ioannis Tsanis
Keyword(s):  
Climate Change ◽  
Flash Flood ◽  
Model Verification ◽  
Peak Discharge ◽  
Climate Change Scenarios ◽  
Flood Wave ◽  
Time Step ◽  
Time Intervals ◽  
The Impact ◽  
Small Basin

Climate change will have a greater impact on the severity of flash floods, since precipitation intensity is expected to increase, even in areas where a reduction of precipitation is possible. This change in climate is expected to increase flood wave speed and its flood wave area extent. A case study of a small basin in the island of Crete was conducted to examine this effect, following the calibration and validation of the flow hydrograph of a flash flood event, in order to achieve model verification with the post-flood data. It was found that the most important parameters that affect the timing and magnitude of the peak discharge are the storage coefficient, the impervious rate and the curve number, as well as the time of concentration. Rainfall distribution was examined in different time intervals in order to study the effect of the intensity of precipitation on the peak hydrograph. From the precipitation records and according to the size of the watershed, the time step of the precipitation in the simulation model is recommended to be less than an hour. In other areas around the basin of interest, severe storms known as Medicanes that pass over Crete can produce higher precipitation in shorter time intervals. The impact of climate change scenarios results in an increase on the peak discharge by creating precipitation of higher intensity. Furthermore, the intensification of precipitation due to climate change results in higher flood depths and flooded area extent, as well as wave velocities.

Proposal for Improving Records Management Practices of Traditional Institutions in Ga Molepo, South Africa

Mousaion ◽  
10.25159/2054 ◽  
2017 ◽  
Vol 35 (1) ◽  
pp. 46-67
Author(s):  
Mahlaga Johannes Molepo ◽  
Linda M. Cloete
Keyword(s):  
South Africa ◽  
Rural Communities ◽  
Management Practices ◽  
Records Management ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Record Keeping ◽  
Local Municipalities ◽  
Management Procedures ◽  
Traditional Institutions

The way in which an institution treats its records is crucial for its survival in a rapidly changing society. The purpose of the study was to investigate the records management practices and challenges faced by traditional institutions of leadership and governance in Ga Molepo, Limpopo, South Africa. The researcher employed a cross-sectional survey in order to quantitatively examine the challenges faced by members of traditional councils. A researcher administered questionnaire was used as a data collection tool to study a stratified sample of 35 members from an estimated population of 350. The findings revealed patterns and trends of non-compliance with records management standards and guidelines. Although there were sporadic cases of record keeping, a greater number of respondents revealed that traditional institutions lack the facilities, equipment, education and trained/skilled personnel to apply correct records management procedures in their daily administration of their traditional communities. The main value of the study is to create awareness of records management as one of the neglected areas in traditional institutions – which are by current legislative arrangement, the closest form of leadership and governance for rural communities in light of their relationship with local municipalities and the Department of Cooperative Governance and Traditional Affairs.

Influence of Knowledge Management Practices on Public Service Delivery by Municipalities

Mousaion ◽  
2019 ◽  
Vol 37 (3) ◽  
Author(s):  
Charleen Musonza ◽  
Ndakasharwa Muchaonyerwa
Keyword(s):  
South Africa ◽  
Knowledge Management ◽  
Service Delivery ◽  
Public Service ◽  
Qualitative Data ◽  
Management Practices ◽  
Integrated System ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Public Service Delivery

This study examines the influence of knowledge management (KM) practices on public service delivery by municipalities in the Eastern Cape province of South Africa. The study sought to determine the factors that have triggered the implementation of KM practices; the effectiveness of KM practices towards public service delivery; and the extent to which KM practices have influenced public service delivery by municipalities in the Eastern Cape province of South Africa. Both quantitative and qualitative methods were employed in this study. Quantitative data were collected through a survey questionnaire administered to a sample of 202 employees at the Raymond Mhlaba Municipality in the Eastern Cape. Qualitative data were collected through observations and interviews of 2 senior managers. The data collected gave a response rate of 72 per cent. The quantitative and qualitative data were analysed descriptively and presented verbatim respectively. The results indicated that the internal and external factors included in this study have contributed to the implementation of KM practices in the municipality. Furthermore, the effective use of KM practices has increased the organisational KM initiative, as well as the provision of services such as electricity, education, transport, and social services by the municipality. The study recommends the establishment of KM awareness and the establishment of an integrated system that will assist in effective knowledge sharing, retention and acquisition across municipalities in the Eastern Cape.

scholarly journals Prioritization of Sub-Watersheds to Sediment Yield and Evaluation of Best Management Practices in Highland Ethiopia, Finchaa Catchment

Land ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 650
Author(s):  
Wakjira Takala Dibaba ◽  
Tamene Adugna Demissie ◽  
Konrad Miegel
Keyword(s):  
Soil Erosion ◽  
Best Management Practices ◽  
Sediment Yield ◽  
Soil Loss ◽  
Crop Production ◽  
Management Practices ◽  
Assessment Tool ◽  
Swat Model ◽  
Sediment Yields ◽  
Soil And Water

Excessive soil loss and sediment yield in the highlands of Ethiopia are the primary factors that accelerate the decline of land productivity, water resources, operation and function of existing water infrastructure, as well as soil and water management practices. This study was conducted at Finchaa catchment in the Upper Blue Nile basin of Ethiopia to estimate the rate of soil erosion and sediment loss and prioritize the most sensitive sub-watersheds using the Soil and Water Assessment Tool (SWAT) model. The SWAT model was calibrated and validated using the observed streamflow and sediment data. The average annual sediment yield (SY) in Finchaa catchment for the period 1990–2015 was 36.47 ton ha−1 yr−1 with the annual yield varying from negligible to about 107.2 ton ha−1 yr−1. Five sub-basins which account for about 24.83% of the area were predicted to suffer severely from soil erosion risks, with SY in excess of 50 ton ha−1 yr−1. Only 15.05% of the area within the tolerable rate of loss (below 11 ton ha−1yr−1) was considered as the least prioritized areas for maintenance of crop production. Despite the reasonable reduction of sediment yields by the management scenarios, the reduction by contour farming, slope terracing, zero free grazing and reforestation were still above the tolerable soil loss. Vegetative contour strips and soil bund were significant in reducing SY below the tolerable soil loss, which is equivalent to 63.9% and 64.8% reduction, respectively. In general, effective and sustainable soil erosion management requires not only prioritizations of the erosion hotspots but also prioritizations of the most effective management practices. We believe that the results provided new and updated insights that enable a proactive approach to preserve the soil and reduce land degradation risks that could allow resource regeneration.

Household solid waste quantification, characterization and management practices in Mthatha city, South Africa

2022 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Motebang Nakin ◽  
Hlekani Kabiti ◽  
Simbarashe Ndhleve ◽  
Vuyayo Tsheleza
Keyword(s):  
South Africa ◽  
Solid Waste ◽  
Management Practices ◽  
Household Solid Waste
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