| 李芷晴,陈立,冯恺,孙昭华.三峡建库后荆江洲滩变形及其与水文情势变化对植被的叠加影响[J].水利学报,2025,56(5):587-598 |
| 三峡建库后荆江洲滩变形及其与水文情势变化对植被的叠加影响 |
| Evolution of channel bars in the Jingjiang River reach after the impoundment of the Three Gorges Reservoir and its combined effects with hydrological regime on vegetation |
| 投稿时间：2024-09-23 |
| DOI：10.13243/j.cnki.slxb.20240612 |
| 中文关键词: 荆江河段 三峡水库 洲滩冲淤 植被变化 |
| 英文关键词: Jingjiang River Three Gorges Reservoir channel bars evolution vegetation changes |
| 基金项目:国家自然科学基金项目（52479074，51879198）；水利部三峡后续研究项目（12630100100020J005） |
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| 中文摘要: |
| 三峡建库后，荆江河段内中枯水历时加长以及水流次饱和导致主槽下切已成为共识，但对于基本河槽以上的洲滩变形特征尚未形成统一认识。本文以荆江河段为对象，根据三峡建库后的观测资料，结合地形法和遥感解译分析法，分区段、分时段研究了不同流量级淹没范围内的洲滩面积变化，分别从河段尺度与局部尺度分析了不同高程的洲滩变形特征，并评估了洲滩变形与水文情势变化引起的植被适宜区调整。结果表明：荆江河段内的洲滩冲淤调整主要发生在2008年以后，枝城—杨家垴区段内的洲滩表现为持续的冲刷萎缩，杨家垴—监利河段内低、中滩萎缩，高滩略有淤积，监利—城陵矶河段内低滩萎缩而中、高滩显著淤积。在低滩萎缩的总体趋势下，航道整治工程虽可遏制局部位置的冲刷甚至促使小范围回淤，但其对中、高滩的影响不大。洞庭湖顶托影响区内的洲滩淤积主要表现在滩面高程增加，但平面形态变化不大。三峡水库进入正常运行期后，洲滩变形与水文情势变化共同导致荆江河段内满足高频次植被覆盖的区域增大了32.0%，枝城—杨家垴、杨家垴—新厂、新厂—监利以及监利—城陵矶各区段内的增幅分别为-5.6%、6.5%、13.3%、95.6%。下荆江尤其是监利以下高滩淤积和植被覆盖区面积增大可能会增大行洪阻力，需引起重视。 |
| 英文摘要: |
| After the impoundment of the Three Gorges Reservoir，it has become a consensus that the increased duration of low and medium flows in the Jingjiang River reach，combined with sub-saturated sediment-containing flows，has caused sustained scouring of the main channel. However，a unified understanding of the evolution characteristics of channel bars above the basic channel has yet to be established. This study focuses on the Jingjiang River reach and analyzes changes in channel bar areas within different discharge based on observational data collected after the impoundment of the Three Gorges Reservoir. Based on morphological change method and remote sensing analysis，variations in channel bar areas across different sections and time periods were examined. The deformation characteristics of channel bars at different elevations were analyzed at both river reach and local scales，and the adjustments in suitable vegetation zones resulting from changes in channel bar evolution and hydrological conditions were assessed. The results indicate that the adjustment of channel bars in the Jingjiang River reach primarily occurred after 2008. In the Zhicheng-Yangjianao section，channel bars exhibited continuous degradation and shrinking，while in the Yangjianao-Jianli section，low and middle bars shrank，and high bars showed slight aggradation. In the JianliChenglingji section，low bars shrank while middle and high bars experienced significant aggradation. Under the overall trend of low bar erosion，although channel regulation projects can prevent localized erosion and may even promote deposition，their impact on middle and high bars is not significant. In the section influenced by backwater from Dongting Lake，the deposition of channel bars is mainly reflected in the increase in elevation，but the change of the planform is not significant. After the normal operation period of the Three Gorges Reservoir began，changes in channel bar deformation and hydrological conditions together resulted in a 32.0% increase in areas suitable for highfrequency vegetation coverage in the Jingjiang River reach. The increases in the Zhicheng-Yangjianao，YangjianaoXinchang，Xinchang-Jianli，and Jianli-Chenglingji sections were -5.6%，6.5%，13.3%，and 95.6%，respectively. There is potential for high bar deposition and an increase in vegetation-covered areas in the lower Jingjiang River，particularly downstream of Jianli，which may increase resistance to flood discharge and should be given due attention. |
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