Design Of Optimal Basic Irrigation Controlling Area Network For Micro-irrigation Based On MATLAB Genetic Algorithms

With the problem of water resources shortage growing in intensity, micro-irrigation as one of the pipeline water saving techniques will be one of the development trend of future agriculture irrigation in our country. There are two valuable and interesting projects for further study in optimization of basic irrigation controlling area network, one is maximum control area or minimum cost per area in unlimited control area, another one is minimum cost per area in limited control area. The two directions have practical significance and theory value in the improvement of operation and management level and the economic benefit.By taking regular layout basic irrigation controlling area network as the research object in this paper, for shortcomings of traditional optimization way of irrigation network, some important and useful improvements in the method for optimization of basic irrigation controlling area network for micro-irrigation was done on the basis of optimization theory and technology achievements from domestic to foreign. The research work and results of this paper are mainly as follows:(1)In this paper, the objective function models of basic irrigation controlling area network in unlimited and limited control area for micro-irrigation are established. The models include maximum control area, the minimum cost per area in unlimited control area and the minimum cost per area in limited control area, respectively. Then the optimal combinations of pipelines which meet the pressure condition in accordance with irrigation uniformity are given based on Matlab Genetic Algorithm Toolbox(GA Toolbox). There are two lateral layout in all models that, unidirectional and bidirectional. Lateral layouts along its longitudinal and width directions in limited control area model are considered as well.(2)The network was considered as a whole in this method. Supposed flow of every lateral emitter is in the condition of the design flow. And in basic irrigation controlling area network system for micro-irrigation maximum pressure drop of all outlets should be less than allowable pressure. Practically, the paper simulated water pressure factors such as the surface slope, the hydraulic gradient for value of every outlet including all laterals and branch pipes.In the method, system allowable pressure beforehand distribution between laterals and branch pipes, and the location discussion of the maximum and minimum water pressure points in the traditional way could be ignored.(3) In order to seek regularity of control area and cost per area,analysis and comparison study based on the parameter adjustment such as diameter of laterals, flow of every lateral emitter should be done. The optimal combinations of pipelines of all models before and after parameter adjustment are analyzed, And the influence law of lateral layouts(longitudinal or width), layout models(unidirectional or bidirectional), branch pipes combination, diameter of laterals and flow of every lateral emitter on control are and cost per area is concluded. It has practical meaning and theory value to parameter prediction and pre-judgment in optimization of micro-irrigation network.