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| DOI：10.13522/j.cnki.ggps.2017.0574 |
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| Analysis of the Factors Affecting Sedimentation in Canals Ditching Yellow River Water for Irrigation |
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GAO Hongyan， WEI Zhanming
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Inner Mongolia Agricultural University, Hohhot 010018, China
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| Abstract: |
| Dengkou is an irrigation district pumping water from the Yellow River for irrigation. Its performance has deteriorated over the past few years due to sediment deposit. The purpose of this paper is to analyze the factors that affected the sedimentation. 【Method】 We calculated the depth of the sedimentation at the entry to the canal by measuring the water levels before and after irrigation, as well as the sediment content of the water at the entry to the pumping station. In the meantime, we also measured flow velocity and flow rate and analyzed the size and size-distribution of the sediments. 【Result】 The sediment at the entry to the pumping station was thickest prior to the first and the fourth irrigation because the pumps had been put at rest for a long period and the sediment content in the water was high. As such, more sediments were pumped into the canal, in which 80% had an average diameter less 50 μm. The amount of sediment pumped into the canal increased with the pumping rate. 【Conclusion】 Under the same conditions, prolonging the rest time of the pump increases the thickness of the sediments at the entry. At a given sediment content, there is a critical pumping rate at which there is no sedimentation. Therefore, improving engineering management can reduce sediment deposition in the canals. |
| Key words: sedimentation; sediment content; characteristics of extraneous sediment; irrigation district |
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