Document Type : Original Article
Authors
Associate Professor, Gorgan University of Agricultural Sciences and Natural Resource
Abstract
Extended Abstract
Introduction
In the design of underground drainage systems, the depth, diameter and distance of the drains are important decision making variables. Depending on the type of target, different combinations of them can be used. In the usual drainage designs, the design variables of the depth and diameter of the drain are determined by using experience and the conditions and facilities of material preparation, and the distance of the drains, after determining the drainage coefficient and water balance, is determined by using the Hooghoudt equation. Since design variables are intrinsically interdependent, methods can be used to determine the best combination of variables that leads to minimum implementation costs. The aim of this research is to optimize the design parameters of underground drainage systems with an economic approach. Optimization is finding the best solution in order to minimize or maximize one or more objectives by observing the constraints of the problem. The present study was conducted based on the current economic situation and observations of the country and on the basis of the actual executive figures of Iran in 2018. In this research, genetic and multiverse algorithm optimization model was used to optimize the main design parameters of the underground drainage system of regional agricultural lands around Gorgan city.
Methodology
In this research, Genetic and multiverse algorithm optimization model was used to optimize the main design parameters of the underground drainage system of regional agricultural lands around Gorgan city. The area of the construction area of the drainage system was around 200 hectares. These areas were divided into 25 plots of 8 hectares and project costs were calculated for each. Using genetic and multi-world algorithm, the design parameters were selected in such a way as to lead to the lowest implementation cost of the underground drainage system. In this regard, the design parameters were selected by combining Hooghoudt equation and optimization algorithms.
Results and Discussion
By applying the genetic algorithm optimization model to the data of the studied lands, the optimal parameters were calculated. Considering the entire search area (permissible depth of drainage installation from 1.5 to 3.5 meters from the ground surface), the results showed that, by entering the drainage coefficients of 1.5, 2, 2.5, 3, 3.5, 4 and 4.5 mm per day the lowest cost of 49.9 million Tomans was obtained in 8 hectares with a drainage coefficient of 4 mm per day, at a depth of 3.13 meters from the ground surface with an installation distance of 79.8 meters and a diameter of 100 mm. Also, the optimal parameters were calculated by applying the multiverse algorithm optimization model. The results obtained from Aliabad land input data showed that by entering the drainage coefficients of 1.5, 2, 2.5, 3, 3.5, 4 and 4.5 mm per day, the lowest cost is equivalent to 49.8 million tomans in an 8-hectare unit with a drainage coefficient of 4 mm per day was obtained at a depth of 3.13 meters from the ground surface with an installation distance of 80 meters and a diameter of 125 mm.
The best design parameters using the genetic algorithm according to the implementation criteria of the drains including diameter, the distance of the drains, the optimal depth and also the costs for an 8-hectare plot including 100 mm, 54 m, 2.11 m and 70.604 million Tomans have been obtained. In the multiverse algorithm, these values are 100 mm, 61.3 meters, 2.25 meters and 63.709 million Tomans, respectively. Also, the cost of the project decreases with the increase of the allowed depth of the drain installation, the lowest and highest costs obtained in the genetic algorithm for the maximum allowed installation depth of 1.75 and 3.5 meters are equal to 110.226 and 51.814 million Tomans, respectively. In the multi-world algorithm, it was obtained as 110.223 and 51.782 million tomans, respectively.
Conclusions
In this research, the optimization model of genetic and multiverse algorithm for lands around Gorgan city was used. The construction area of the drainage system was about 200 hectares. These areas were divided into small plots of 8 hectares and the design costs for that small unit were calculated. Therefore, 25 units of 8 hectares have been considered for the study area. In this study, using genetic and multi-verse algorithms, these parameters were selected in such a way as to lead to the lowest operating costs of the underground drainage system. Results showed the best design parameters using the genetic algorithm according to the implementation criteria of the drains including diameter, the distance of the drains, the optimal depth and also the costs for an 8-hectare plot including 100 mm, 54 m, 2.11 m and 70.604 million Tomans have been obtained. In the multiverse algorithm, these values are 100 mm, 61.3 meters, 2.25 meters and 63.709 million Tomans, respectively.
Acknowledgement
The responsible author of the article is grateful to the Jihad Keshavarzi Organization of Gorgan, this research was carried out with the financial support of this organization.
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