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| DOI：10.13522/j.cnki.ggps.2017.0642 |
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| A Computer Software to Design Subsurface Drain and Open Trench as a Hybrid Drainage System for Farmland |
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LI Huizhen, LI Fahu, ZHOU Xinguo, SHI Xueshuang, ZHANG Wenchao
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College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China; Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China
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| Abstract: |
| 【Objective】 Subsurface drain is a common drainage technique to keep groundwater table below a critical depth. The purpose of this paper is to present a model and computer program to help design subsurface drain and open ditch as a hybrid drainage system for farmland. 【Method】 The model was based on hydrodynamics of soil water and considered both drainage and evaporation; the water flow was solved numerically. 【Result】 For the cases we studied, considering evaporation allowed the distance between adjacent drains to increase by 2.9%~17.3% compared with scenarios without evaporation; increasing the drain-drain distance from 15 m to 25 m reduced the groundwater table drawdown by 24.7%~27.5%. Increasing the depth of the drain from 1.5 m to 2.0 m enhanced the groundwater table drawdown by 34.8%. Comparison with the literature results showed that the maximum relative errors of the model simulations was less than 1.2%. The code ran fast and, in most circumstances, could give the final results in less than 5 seconds. 【Conclusion】 The model and the software we developed can be used as a tool to design drainage systems to control soil salinity and to ameliorate waterlogging. |
| Key words: subsurface pipe drainage; pipe spacing; pipe buried depth; calculation model; software programming |
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