Abstract
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.