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| DOI：10.13522/j.cnki.ggps.2023538 |
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| Comparison of different methods for calculating farmland drainage modulus |
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YOU Lijun, WANG Shaoli, LIU Changrong, FAN Lijun, LI Zongliang
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1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resource and Hydropower Research, Beijing 100038, China; 2. Heilongjiang Province Service Center for Rural Water Conservancy and Hydropower, Harbin 150040, China; 3. 290 Farmland Water Authority, Hegang 156200, China;
4. Suibin Farmland Water Conservancy Department of Agriculture Development, Hegang 156200, China
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| Abstract: |
| 【Objective】Drainage modulus is an important parameter for designing drainage systems in farmland. Taking Suibin county in Sanjiang Plain as an example, this paper analyzes its runoff and drainage modulus. 【Method】The study site was an area prone to waterlogging. We first calculated the runoff (RO) using historical data on precipitation, pumping stations and land usage, and then estimated it using the runoff generation method (RGM) and the SCS-CN method (RSCS). The drainage modulus associated with each runoff was calculated using both empirical formulae (QE) and the average draining method (QA). The runoff and drainage modulus calculated by different methods were tested against measured data in the field.【Result】In the same year and under the same rainfall return period, the measured runoff increased with rainfall duration, while under the same rainfall duration and the same rainfall return period, it decreased with passage of years. The runoff and drainage modulus calculated from different methods differed from the experimentally measured data. For heavy rainfalls, the runoff estimated from different methods was ranked in the order of RGM>RSCS>RO, while for other rainfalls, it was ranked in the order of RSCSQE, whereas for rainfalls lasting 3 days, QA
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| Key words: drainage modulus; runoff; runoff generation method; SCS-CN method; empirical formula; average draining formula |
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