Browsing by Author "Kanda, Edwin"

Now showing 1 - 7 of 7
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    Coupling hydrological and crop models for improved agricultural water management
    (Bulgarian Journal of agricultural science, 2018-06-01) Kanda, Edwin; Mabhaudhi, T.; Senzanje, Aidan
    Understanding the relationships among plant, soil, and water is important in agricultural water management practices. Simulation of the soil water balance is central to improving crop water productivity. Individual crop or hydrological models have shortcomings due to the simplification of the surface or subsurface processes. Coupling of crop and hydrological models helps in understanding the complex processes involved in crop production. This review highlights the application of coupled crop and hydrological models in simulation of crop response to water availability. The hydrological models considered are CHAIN-2D, HYDRUS-1D, HYDRUS 2D/3D, and MODFLOW. The crop growth models considered are the water-driven model (AquaCrop), solar-radiation driven model (EPIC), and the carbon-driven models (WOFOST and DSSAT). HYDRUS-2D is the successor to CHAIN-2D. MODFLOW is a popular model especially in simulating groundwater flow while HYDRUS is satisfactory in the simulation of water dynamics in the vadose zone. From the review, it can be deduced that HYDRUS-1D has been coupled with all the crop models considered except DSSAT. EPIC – CHAIN-2D and MODFLOW-DSSAT were the other applications. Further research needs to consider linking 2D soil water models with any of the crop growth models for a better representation of the soil water dynamics and therefore accurate simulation of the soil water balance.
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    Coupling Hydrus 2D/3D and AquaCrop Models for Simulation of Water Use in Cowpea (Vigna Unguiculata (L.) Walp)
    (Springer Link, 2021-01-01) Kanda, Edwin; Senzanje, Aidan; Mabhaudhi, T.
    Simulation of the soil water balance requires reliable representation of the main hydrological processes such as infiltration, drainage, evapotranspiration and run off. In a cropping system, the determination of the soil water balance is necessary to facilitate decisions regarding water management practices such as irrigation scheduling. This may require the coupling of hydrological and crop models. This study sought to determine the water use of cowpea under irrigated conditions in different environments of South Africa. The study considered two irrigation types, subsurface drip irrigation (SDI) and Moistube irrigation (MTI) and two environments characterized by clay and sandy soils. The study was accomplished using a hydrological model (HYDRUS 2D/3D) and AquaCrop (crop model). The crop characteristics were obtained using AquaCrop while HYDRUS 2D/3D was used to generate optimum irrigation schedules and the soil water balance. Thereafter, the water use and yield of cowpea was determined. The average grain yield and biomass was 2600 kg ha−1 and 10,000 kg ha−1, respectively, with the difference between the two sites being less than 5% under both SDI and MTI. The water use and water use efficiency (WUE) varied from 315 to 360 mm and 0.67 to 1.02 kg m−3, respectively, under the two irrigation types in the two sites considered. The WUE was higher under SDI than MTI, but the differences were less than 10%. This showed that response of cowpea under MTI was not different from SDI.
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    DETERMINATION OF IRRIGATION WATER REQUIREMENT OF TOMATO CROP IN RACHUONYO NORTH SUB CATCHMENT OF WESTERN KENYA USING CROPWAT MODEL
    (East African Agricultural and Forestry Journal, 2022-09-09) Odhiambo, Kevin; Basil, T; Ong'or, Basil; Kanda, Edwin
    Irrigation water management is necessary for a successful irrigation system. Knowledge and tools on irrigation management is thus a requisite for profitable and sustainable use of the scarce water resources in Kenya. The study determined the irrigation water requirement of tomato (Solanum lycopersicum L.) crop in Rachuonyo catchment using CropWat model and the area climate, soils and tomato crop data. The study findings indicated that crop evapotranspiration (ET c) and net irrigation water requirement (IR) of tomatoes in the study area was 584.0 mm season-1 and 340.7 mm season-1 , respectively. The seasonal water requirement for tomatoes growing in a smallholder farm of 0.607 ha farm in the area was found to be 2,297.97 m 3 season-1. The study revealed that CropWat model coupled with accurate area climate, soils and crop data can be used as a reliable decision support tool for the management of irrigation water for the region.
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    Effect of Contractor Capacity and Monitoring and Evaluation on Completion of Water Projects among Water Services Boards in Kenya
    (International Journal of Research in Management, Science & Technology, 2017-04-17) Mutoro, Cleophas; Asinza, Karen; Kanda, Edwin; Malenya, Abraham
    In Kenya, many water projects experience delays in completion even after substantial investments. The main objective of this study was to determine the influence of monitoring and evaluation and contractor capacity on completion of water projects among Water Services Boards in Kenya. Lake Victoria Water Services board was used as a case study. This study employed both quantitative and qualitative research and adopted descriptive research design. The target population for this study was 50 water projects all of which were studied as a census. Census technique was used to select all 200 engineers who had been previously directly involved in the construction of the respective projects to participate in the study as respondents. The main data collection instrument was a semi-structured questionnaire. A questionnaire return rate of 84% was achieved. Data analysis employed both descriptive and inferential statistics. Measures such as frequencies and percentages and Karl Pearson's correlation were computed and used to explain the relationship between the variables. Monitoring and Evaluation (M&E) factors studied included stakeholder participation and communication strategy which had a weak but significant positive relationship with project completion (r = 0.299, p < 0.01). Contractor capacity had a moderate positive relationship with project completion (r = 0.657, p < 0.01).
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    Factors Influencing Completion of Water Projects in Kakamega County, Kenya
    (International Journal of Research in Management, Science & Technology, 2016-08) Kanda, Edwin; Muchelule, Yusuf; Mamadi, Simon
    The main aim of this study was to investigate factors that influence completion of water projects in Kenya using Kakamega County as a case study. The specific objectives of the study were to determine the effect of client-related factors and contractor-related factors. The instrument of data collection was questionnaires. The target population consisted of 104 employees working for water projects in Mumias and Lugari, and also contractors and professionals who have been engaged in water projects in Kakamega County. Simple random and purposive sampling was used to select 90 respondents who formed the sample size. The response rate was 82%. The data was analyzed using descriptive statistics and correlation. The main factors that were associated with client included financial capacity, owner interference, the imposition of contract duration , decision-making ability, and change in project scope which had a positive relationship with project completion (r = 0.302, p <0.05). The contractor-related factors studied were financial capacity, equipment availability and quality, skilled workforce, site supervision ability, material availability, and control over sub-contractors which had a positive relationship with project completion (r = 0.668, p < 0.05). Therefore, both client-related and contractor-related factors had a significant relationship with project completion.
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    The Effect of Consultant Related and External Factors on Completion of Water Projects in Kakamega County, Kenya
    (International Journal of Civil and Structural Engineering Research, 2016-09) Kanda, Edwin; Muchelule, Yusuf; Mamadi, Simon; Musiega, Douglas
    Abstract Inability to complete projects is among the challenges faced in the course of executing construction projects. The most widely used project success criterion is meeting time, quality and cost requirements. The objective of this study was to investigate the effect of consultant related and external factors on completion of water projects in Kakamega County, Kenya. The instrument of data collection was questionnaires. The target population consisted of 104 employees working for two water projects in Mumias and Lugari both in management and lower levels. Simple random sampling was used to select 90 who formed the sample size out of which, 74 respondents returned the questionnaires representing 82% response rate. Analysis of data was done using descriptive and inferential statistics using correlation and regression. Consultant related factors considered included experience, skilled personnel, coordination, site supervision and decision-making ability and they had a significantly fairly strong positive relationship with project completion ( r = 0.583, p < 0.05). External factors of political interference, industrial action, regulation, taxation and material unavailability in the market had a weak but significant positive relationship (r = 0.312, p < 0.05) with project completion. The overall regression model gave R2 of 0.409. This showed that that the variations around the means in consultant related and external factors is about 41%.Key words: Kakamega County, consultant related factors, external factors, project cost, project completion time and project quality
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    The Water Act 2002 and The Constitution of Kenya 2010: Coherence and Conflicts Towards Implementation
    (International Journal of Disaster Risk Reduction, 2013) Kanda, Edwin; Taragon, John; Kimokoti, Susan; Waweru, Sam
    The water Act 2002 provides for Integrated Water Resources Management along the River Basin that is the best practice worldwide and in accordance with Dublin Principles. Prior to reforms in the water sector, water supply and sanitation and water resources management in Kenya faced huge challenges among them being institutional weaknesses, inadequate funding, conflicts due to overlapping roles and responsibilities of key public sectors in the water Act. The constitution of Kenya 2010 recognizes water and sanitation services as a basic right. Before the enactment of the new constitution, the old constitution did not provide for water provision as basic right. This paper presents an analysis of the water Act in relation to the new constitution of Kenya and the challenges facing its implementation. Ways of harmonizing the water Act with the new constitution are explored. It is imperative to note that the Water Act does not recognize water as a basic right and therefore some sections of the Act have to be amended to conform to the constitution which enshrines it in the Bill of Rights.