No description available.

M.Ing. / An optimization system, consisting of a water office database, monitoring stations, communication system and simulation model is described. The main objective of the optimization system is to minimize management related distribution losses in irrigation canals. The optimization system can be implemented in parts, or as a whole, depending on the requirements of the user. This property makes it flexible and facilitates systematic implementation on an irrigation scheme. The water office database which was developed on an IBM-PC promotes computerization of the water register and facilitates compilation of water accounts. Input hydrographs can also be recalculated on short notice. The monitoring stations consist mainly of waterloggers and sensors which record waterdepth as a function of time. These stations can be telemetrically connected to a computer in the water office. The telemetric connection makes it possible to monitor canal operation from the water office and can _be used as an aid in water loss control. The recording stations play an important roll in the calibration of the simulation model. The simulation model was also developed on an IBM-PC and simulates unsteady non-uniform flow of water in irrigation canals. The simulation of unsteady non-uniform flow of water in irrigation canals consists of the solution of the St Venant equations which were discretized with the aid of the Preissmann scheme. The model can simulate a number of watertakeoffs and is only restricted to a maximum of 1300 takeoffs per canal. Changing slope, changing roughness, manual and upstream controlled sluices, pressure controlled and manual turnouts, weirs, transition losses, discharge and waterdepth as a function of time at the end of the canal, free overflows, any .change in cross section and any losses in the form of seepage and evaporation can also be taken into account. The five different types of sections which can be handled are trapeziodal, rectangular, circular, triangular and parabolic sections. Flow in irregular cross sections of rivers can be simulated by storing cross section properties in table format. Waterflow in pipelines and rectangular culverts can also be simulated over short distances. The output of the computer program at each node is available in the form of hydrographs, with a choice of output to a printer or screen. The time dependant variables that can be examined are discharge, waterdepth, velocity and cross sectional area of flow.

No description available.

Call number: LD2668 .T4 1984 B72 / Master of Science

In hierdie studie word die probleem van die onbevredigende verspreiding en gebruik van toegepaste navorsingsresultate oor besproeiingstegnologie in Suid-Afrika, ondersoek. Die probleem is uit 'n inligtingkundige hoek benader, met inagneming van die rolspelers in die verspreidingsproses, asook faktore wat hul optrede beinvloed. 'n Kwalitatiewe navorsingsbenadering is aangewend in 'n verkennende ondersoek na die verspreiding van twee navorsingsverslae oor besproeiingskedulering. Deur middel van onderhoudvoering met die vernaamste groepe rolspelers is vasgestel hoe die verspreidingsproses werklik verloop het. Daar is bevind dat verspreiding nie plaasgevind het soos deur die verspreider aangeneem is nie, waarskynlik as gevolg van 'n verskeidenheid faktore binne die sosiale stelsels van die rolspelers. Laastens word daar voorgestel dat verspreiders die bevindings van hierdie studie by die beplanning van toekomstige verspreidingstrategiee in ag behoort te neem. / This study addresses the problem of unsatisfactory dissemination and utilisation of applied research results irrigation technology in South Africa. The problem is approached from the Information Science point of view, taking into account the various role players in the dissemination process, as well as the factors which influence their behaviour. A qualitative research approach is applied to an exploratory investigation of the dissemination of two research reports on irrigation scheduling. In order to establish the exact way in which the dissemination process took place, the major role players were interviewed according to a semi-structured interviewing schedule. It is concluded that dissemination did not take place as assumed by the disseminator, probably as a result of the various factors within the social systems of the different role players. Finally it is proposed that disseminators take cognisance of the recommendations of this study when planning dissemination strategies in future. / Information Science / M. Bibl. (Inligtingkunde)

No description available.

A tractor mounted three-point hitch implement was developed to extract and collect subsurface trickle irrigation laterals from the soil. Power to the implement was supplied by the tractor hydraulic system to the three-point hitch and two remote hydraulic circuits. In operation, the implement loosened the soil around the lateral, extracted the tubing from the soil, wound it on a reel assembly, and then dropped the roll of tubing at the end of the row. Draft power requirements averaged 14.5 kW (19.4 hp) and hydraulic power averaged 0.56 kW (.75 hp) when the one row implement was operated at 7.2 km/h (4.5 mph). Field capacity of the one row implement averaged 0.19 ha/hr (.47 ac/hr) when operated in 100 m (328 ft) long rows.

Implementation of a small-scale irrigation project in southern Mauritania is analyzed in this report. The main objective is to demonstrate that small-scale irrigation farming is the best suited solution for Mauritania's agriculture. To reach this objective different steps are taken in this study. The first step highlights the different aspects affecting the development of agriculture in the Senegal River basin such as climatic, environmental, and socio-economic constraints. The next step is the design of a small-scale irrigation system for a small region in the middle valley of the Senegal River called the Dirol plain. Finally, analysis and discussion of the design is made. This discussion centers on the problems faced during the design and the different assumptions made to implement it. The conclusion section addresses the feasibility of the design and gives recommendations that will help improve the design process for future work in the Senegal River basin. / Graduation date: 1996

Water Brief, Fourth Draft / 6.16.76 / Introduction: The need for an efficient method of storage of water in arid zones has long been recognized. Efforts have been made everywhere to develop small storage tanks to provide water at critical periods. However, most of the existing tanks have such annual or seasonal evaporation losses that they are equal or even greater than the average depth of the tank. Thus many of these tanks are completely depleted before the end of the dry season, often with dramatic consequences for human beings, livestock or agricultural activities depending on the water supply. Reducing the heavy evaporation and seepage losses in these tanks is an important way to increase the supply of water. Several methods have been developed to reduce these losses but one of the most effective ways is to make the tanks with a smaller surface but deeper. The importance of making tanks deeper has been recognized for many years but there are several constraints for achieving depth in tanks: (a) the gradient of the water stream, (b) the unsuitability of dozers to work in deep pits, and (c) shallow soils. However, these constraints can be removed by using high rise banks and water pumps. Efficiency can also be improved by keeping the water concentrated. With this idea in mind, Mr. Cluff, FAO Consultant, has developed the concept of the compartmented tank, which is being tried out successfully in Mexico, and whose main features are summarized below.

Project Completion Report, OWRT Project No. A-082-ARIZ / Agreement No. 14-34-0001-8003, Project Dates: October 1977-September 1978 / Acknowledgement: The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1978. / This report contains the results of a one year study to apply the compartmented reservoir concept to water storage problems in Arizona. The range of selected projects was from a ten thousand cubic meter (8.1 af) reservoir for a water harvesting agrisystem at Black Mesa, to a 238 million cubic meter (200,000 af) flood control dam, Tat Momolikot Dam on the Papago Reservation, to supply water for irrigation. Other sites studied were the Santa Cruz River at Continental, to supply an industrial /domestic water, Leslie Creek site for recreation, and improvement of Mormon Lake for recreation. Evaporation from Tat Momolikot and Mormon Lake are presently consuming most of the available water. Through compartmentalization this evaporation can be significantly reduced. At the other potential dam sites on the Santa Cruz and Leslie Creek the use of a compartmented reservoir will make these otherwise marginal projects practical. The Black Mesa Agrisystem is presently demonstrating the utility of the compartmented reservoir system.