Problems Faced and Advances Made by Agricultural Engineers in Southern and Eastern Africa

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is an Invited Paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 5 (2003): A. Senzanje. Problems Faced and Advances Made by Agricultural Engineers in Southern and Eastern Africa. Vol. V. March 2003

Water-use efficiency on commercial wheat farms in Zimbabwe

A conference paper on wheat production in Zimbabwe in the period before Zimbabwe's land reform programmeWheat is grown commercially in Zimbabwe as a fully-irrigated winter crop (May-September) in the highveld, middleveld and lowveld on medium-to-heavy textured soils. Approximately 75% of the commercial wheat farmers are located in the Hunyani and Mazowe Valleys of the highveld (mean elevation of 1442m) and the rest are scattered in the middleveld and lowveld, with a significant concentration in the lowveld (mean elevation of 443m) In Zimbabwe, winter wheat is irrigated by overhead sprinkler systems. Virtually all farmers hand move their irrigation equipment, although about four farmers are experimenting with low-pressure centre pivot systems.The research supporting the preparation the proceedings papers was financed by the U.S. Agency for International Development, Bureau of Science and Technology; Bureau for Africa; and the Southern Africa Regional Programme

Performance assessment of water delivery to a smallholder irrigation scheme in Zimbabwe: Nyanyadzi case study

A research paper illustrating how potential benefits from smallholder irrigation schemes are rarely realised due to unsatisfactory performance of their water delivery systems in rural Zimbabwe.The potential benefits from smallholder irrigation schemes are rarely realised due to unsatisfactory performance of their water delivery systems. A study was conducted to quantify and evaluate water delivery performance indicators of adequacy (Ad), equity (Eq) and dependability (Dp) in three sub-blocks of Nyanyadzi smallholder irrigation scheme using water requirement analysis and a questionnaire survey. The water delivery performance evaluation was carried out between October 1996 and January 1997 for two maize crops under supplementary irrigation and for two consecutive irrigation cycles. Water supply adequacy (ratio of supply to demand) in the first cycle was good (Ad>1.21) and became marginally good (0.96 to 1.01) and poor (Ad0.2) at 73 percent of the 42 locations studied in the canal network. Results of a questionnaire survey revealed that the performance of the water delivery system was consistently low. Poor adequacy, equity and reliability of water supply were perceived respectively by 57 percent, 53 percent and 77 percent of the 30 irrigators interviewed. It was concluded that management input should be intensified in head block A to ensure better water deliveries to the scheme

Estimation of small reservoir storage capacities in Limpopo River Basin using geographical information systems (GIS) and remotely sensed surface areas: case of Mzingwane catchment

The current interest in small reservoirs stems mainly from their utilization for domestic use, livestock watering, fishing and irrigation. Rarely were small reservoirs considered in the water resources system even though they are important in water resource planning and management. The main limitation being lack of knowledge on small reservoir capacities, for the methodologies used to quantify physical parameters of reservoirs are costly, time consuming and laborious. To address this challenge an attempt has been made in this study to estimate small reservoir storage capacities using remotely sensed surface areas. A field study on 12 small reservoirs was carried out in Mzingwane catchment in Limpopo River Basin; Zimbabwe. The depths of water accompanied with their coordinates were measured; from which area and capacity were calculated for each reservoir using geographical information system based on data acquired from the field and that from satellite images. The output data was compared and a linear regression analysis was carried out to establish a power relationship between surface area and storage capacity of small reservoirs. The Pearson correlation analysis at 95% confidence interval indicated that the variances of the two surface areas (field area and image area) were not significantly different (p < 0.05). The findings from linear regression analysis (log capacity–log area) show that there exist a power relationship between remotely sensed surface areas (m^2) and storage capacities of reservoirs (m^3), with 95% variation of the storage capacity being explained by surface areas. The relationship can be used as a tool in decision-making processes in integrated water resources planning and management in the river basin. The applicability of the relationship to other catchments requires further research as well as investigating the impacts of small reservoirs in water resources available in the river basin by carrying out a hydrological modelling of the catchment

Farmers` satisfaction with the performance of the Mooi River Irrigation Scheme, KwaZulu-Natal, South Africa

Farmer satisfaction with using an irrigation service can be used as a  measure of performance of an irrigation scheme. An investigation was  instituted to determine factors that significantly influence the satisfaction  status of farmers at the Mooi-River Irrigation Scheme (MRIS) in KwaZulu  Natal, South Africa. A multinomial Logit regression model was employed to  analyse the response of the farmers. It was established that about 57% of  the farmers are satisfied with using the irrigation service, 30% are not and  13% are neutral. The majority of farmers, accounting for 85%, either never went to school or had only primary level schooling and these are mostly  women, who own close to 80% of the plots in the scheme. Statistically  significant results show that 6 household-level factors affect the satisfaction of farmers with using an irrigation service, i.e., gender of head of  household, level of education attained by the household head, training  received in water management, farmers’ perception of the fairness of water distribution, the number of days in a week that plotholders receive water,  and the participation of farmers in the inspection of irrigation infrastructure on the scheme. This study recommends formulation of policies to train  farmers in water management and to support farmer participation in  scheme management.Keywords: Farmer satisfaction, technical performance, multinomial Logit regressio

Using network analysis to analyse the complex interaction of factors causing the failure of small-scale water infrastructure (SWI) in the rural areas of South Africa

Some parts of the rural areas of South Africa are receiving water services below the legislative standards stipulated in the Water Services Act (1997) of South Africa. is is because small-scale water infrastructures (SWI), including standpipes, handpumps and windmills, are failing to supply adequate water in rural communities for various activities that enhance their livelihoods. is is due to technical, community, institutional, and environmental factors. Literature indicates that these factors are complex in nature. However, research on their complex interactions has been limited. erefore, the complex interactions of the factors causing SWI failure were investigated and analysed in this study. A qualitative research approach was employed to investigate the factors that cause failure of SWI. e network approach combined with graph theory and the community structure method were used to generate a theme and domain network that allowed for a systematic analysis and interpretation of the causes of SWI failure in the study area. e major causes of failure identied include: (i) the use of a top-down approach to implement water projects in rural communities without consultation, (ii) sharing of SWI in high numbers due to the limited number of SWI available/functional, resulting in overloading and increased breakdowns, and (iii) drying up of water sources due to poor siting leading to vandalism of SWI. Overall, the causes of SWI failure are as a result of the complex interactions of dierent categories of factors. e theme and domain network is a powerful tool that can be used represent and analyse the complex interactions. It is therefore imperative for interventions aiming to improve rural water supply to analyse the complex interactions of the causes of SWI failure to understand the underlying problems at a level of a system, in order to propose suitable solutions.Keywords: network analysis, operation and maintenance, rural communities, small-scale water infrastructur