Modelling of “field-to-field” irrigation method in Paddy basins for efficient water management

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dc.contributor.authorNkhoma Oscar S.
dc.date.accessioned2026-04-13T10:27:49Z
dc.date.available2026-04-13T10:27:49Z
dc.date.issued1998
dc.descriptionDissertation
dc.description.abstractIn rice fields the most common traditional irrigation method is field-to-field irrigation method, i.e. conveyance of water across a paddy basin bund through a simple weir or circular pipe to irrigate the next basin. In using the method, there is uncertainty as to when the //nth basin, in a cascade, will receive the water after the preceding basins have attained the required depths. The method has been recognized and is practiced in some schemes in the sub-Saharan Africa. The method is commonly practiced by rice farmers in water scarce conditions. A farmer is tempted to tap water available in the neighbouring basin which has received water when there is low flow in the canal The study to model field-to-field irrigation method in paddy basins was conducted at Kasitu Self-help irrigation scheme in Malawi. This system of irrigation is practiced at this scheme. Reservoir routing equation was adopted and used to develop irrigation water routing model for paddy basins in field-to-field irrigation method by incorporating the factors associated with paddy basins. The model was tested with data obtained from Kasitu Self-help irrigation scheme. The model showed high precision in predicting paddy basin water storage with given inflows and outflows in a specified time, hence it was able to predict closely the time of fill of a given depth in a paddy basin. The results from the statistical analysis of the observed and calculated changes in water storage (in depth units) using the method of analysis of variance (ANOVA) at 5% significant level showed no significant difference in 11 sets of data out of 15 sets of data. The study revealed that the factors which affect water storage in a paddy basin and hence time of fill includes the initial soil water content, surface water inflow, surface water outflow, vertical seepage and percolation through the basin base, horizontal seepage across the bunds with water loss through cracks and fissures, evapotranspiration, and rainfall. The time of fill of n basins in a cascade of paddy basins was obtained as the summation of the times of fill of each of the n basins. The distance of travel of the stream flow was taken as the summation of the longitudinal distances of each basin in the direction of flow to the water front. Basin storage, time of fill, and distance travelled by the water front are all dependent on stream size (inflow and outflow), basin size and the associated water losses. The study proved that water travel time and time of fill of a paddy basin is predictable by using the factors which affect water storage in paddy basins. The computer program developed reduces the many calculations involved in the process to simply entering the raw data or some processed data on choice, hence serve time. It also helps to eliminate some simple errors which may occur in the calculation process. It is recommended that the method be adopted in the design process of paddy should also serve as measuring devices for irrigation water basin irrigation systems. The weirs used in the method are recommended that they should also serve as measuring devices for irrigation water
dc.description.sponsorshipSACCAR/GTZ and Mr and Mrs J. Kapala
dc.identifier.urihttps://www.suaire.sua.ac.tz/handle/20.500.14820/7473
dc.language.isoen
dc.publisherSokoine University of Agriculture
dc.subjectField irrigation
dc.subjectWater management
dc.subjectModelling field
dc.subjectPaddy basins
dc.titleModelling of “field-to-field” irrigation method in Paddy basins for efficient water management
dc.typeThesis

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