| 横断面概化对河道内生态需水计算的不确定性评估 ——以云南昆明海口河为例 |
| Effect of Different Geometries in Generalizing Cross-sections for Calculating River Flow: A Case Study of Haikou River in Kunming, Yunnan Province |
| 投稿时间：2018-12-24 修订日期：2021-01-22 |
| DOI：10.15928/j.1674-3075.201812240336 |
| 中文关键词:湿周法 生态需水 横断面概化 海口河 |
| 英文关键词:wetted perimeter approach ecological water requirement cross transect generalization Haikou River |
| 基金项目:国家自然科学基金（41701631）；云南省科技计划项目重点研发计划（2018BC002） |
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| 中文摘要: |
| 河道生态需水是维持河流生态系统健康的水量基础，计算方法的准确性成为影响生态需水的关键因素。湿周法是一种基于流量与湿周关系的水力学模型，在确定两者关系时多采用与实际河道断面有差异的概化断面计算，可能导致生态需水计算的不确定性；评估不同河道断面概化方法的影响，对指导断面概化具有十分重要的意义。基于云南昆明海口河实测大断面资料，采用4种常见断面概化方法计算了生态需水。结果显示：（1）河道横断面概化对湿周法生态需水的计算结果有显著影响，4种断面概化方法得到的河道生态需水差异显著，生态需水结果最大相差88.29倍；（2）与未概化结果相比，三角形概化法得出的生态流量偏差最高，可相差13.65 m3/s，矩形概化法得出的生态流量偏差最低，最低仅相差0.81 m3/s；（3）断面概化对生态需水的影响程度还受拐点判别方法的影响，斜率法计算结果均大于曲率法计算结果，其中三角形概化方法受拐点判别影响最大，两种方法的估算结果相差11.65 m3/s，矩形概化不同拐点判别结果仅相差0.08 m3/s。研究表明，在湿周法计算生态需水的应用中，断面概化方法对结果的影响显著，且不同概化方法的影响程度不同，合理概化断面在湿周法中是可行的，综合考虑了生态流量和湿周合理性，推荐采用矩形对海口河断面进行概化。 |
| 英文摘要: |
| Meeting the ecological water requirement of rivers is crucial for maintaining the health of river ecosystems, and flow calculations have become an important issue in river protection research. The wetted perimeter approach uses a hydraulic model to estimate river flow based on the relationship between discharge and wetted perimeter, but the accuracy of flow estimation depends on accurately representing the river cross-section. However, river beds are highly irregular and the cross-sectional area is difficult to determine. This leads to uncertainty in calculating flow and, therefore, generalizing the geometry of the cross-section is a critical step in flow calculations. In this case study of the Haikou River at Kunming City, we calculated the ecological water requirement using cross section measurement data and test its fit to four common cross-section geometries. The objective was to assess the effect of different transect generalizations on the calculated flow and provide guidance for selecting an appropriate transect generalization. Results show that: (1) The generalization used for the cross-section significantly effects the calculated flow, a factor of 88.29 between the smallest and largest result; (2) Compared with the measured cross-section data, the triangular generalization resulted in the largest deviation (13.65 m3/s), and the rectangular generalization had the lowest deviation (0.81 m3/s); (3) The influence of transect generalization on the environmental flow requirement is also affected by the slope and inflection point. Generally, a slope of 1 is higher than the maximum curvature of the stream bed. In terms of the four generalization methods, the triangular generalization was affected dramatically, with the difference of 11.65 m3/s between the two different inflection point determinations, and the rectangular generalization only had the difference of 0.08 m3/s .The generalization giving the best flow estimate is the generalization with the geometry that best approximates the shape of the river cross-section. For the Haikou River, a rectangular geometry gave the best flow estimate and triangular geometry gave the worst estimate. Thus we recommend a rectangular geometry for generalizing the Haikou River cross-section. |
| 王明净,袁 鹏,张 帆,李金城,高 伟.2021.横断面概化对河道内生态需水计算的不确定性评估 ——以云南昆明海口河为例[J].水生态学杂志,42(1):10-16. |
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