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1.
近30年洞庭湖季节性水情变化及其对江湖水量交换变化的响应 总被引：1，自引：1，他引：0
江湖水量交换的变化影响着通江湖泊洞庭湖的水情,进而影响湖区社会经济及生态的可持续发展.以洞庭湖城陵矶站、南咀站以及长江干流宜昌站、螺山站1981-2012年逐日水位、流量观测数据为基础,采用单位根检验、方差分析和水位-流量绳套曲线等方法对洞庭湖季节性水情变化特征进行提取,并探究江湖水量交换变化对其产生的影响.研究表明:近30年来洞庭湖水情呈阶段性特征,与相对稳定的1981-2002年相比,2003-2012年湖泊水位总体呈下降趋势,年均水位下降0.43 m;枯、涨、丰、退水期各季水情变化特征为:2003年以后洞庭湖丰水期水位平均下降0.60 m,呈现出"高水不高"现象;退水期水位平均下降1.49 m,退水加快;枯水期水位略有上升,平均上升0.18 m;涨水期水位变化不明显.湖泊退水期水位降幅最为明显,尤其是10月大幅下降,平均下降2.03 m,有提前进入枯水期的趋势.水情变化与江湖水量交换变化密切相关:丰水期,三口(松滋、太平和藕池)分流量减小在一定程度上降低湖泊水位;退水期,三口分流量减小叠加城陵矶出口长江水位下降对洞庭湖产生拉空作用,湖泊出流加快水位被拉低;枯水期,主要是1 3月,城陵矶出口长江水位上升对湖泊顶托作用增强,湖泊出流减缓水位略有抬升. 相似文献
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洞庭湖地处北亚热带季风湿润气候区,水情时空变化尤为明显.为了探明洞庭湖水位时空演变特征,以洞庭湖6个水位站(城陵矶、鹿角、营田、杨柳潭、南咀、小河咀)、出入湖流量("三口"总入湖流量、"四水"总入湖流量、城陵矶出湖流量)和长江干流流量(宜昌、螺山)等1985-2014年逐日数据为基础,通过构建泰森多边形计算湖泊水位,运用Morlet小波分析、层次聚类分析和地统计理论研究湖泊水位的周期性变化规律及空间分布格局和自相关性.研究结果表明:洞庭湖水位变化具有典型的季节性,且年际变化具有28和22 a的多时间尺度特征;水位空间分布格局呈现出小河咀、南咀、杨柳潭(Group 1)以及城陵矶、鹿角、营田(Group 2)两种聚类,且在不同水文季节的空间自相关性依次表现为丰水期退水期涨水期枯水期.通过建立两类水位在不同水文季节与径流量的多元逐步回归模型揭示了洞庭湖水位时空演变的驱动因素,其中Group 1水位演变主要受长江干流水文情势的影响,Group 2水位演变由出入湖径流量和长江干流径流量共同作用,并随着不同水文季节江湖关系的改变以及湖泊自身水力联系的变化而变化.研究结果对于科学认识洞庭湖水位的时空演变规律以及湖泊生态系统保护和水资源的规划、管理与调控具有重要意义. 相似文献
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河湖水文连通性强弱对于维系流域水资源安全、河湖生态系统稳定等方面具有重要意义.本文首先利用1960-2019年松滋口新江口与沙道观两站与干流枝城站实测水文资料以及河道典型横断面地形资料,采用Mann-Kendall法与趋势线法分析讨论枯水期松滋口分流变化的特征与诱因,然后,针对枯水期松滋口河道的分流问题提出河道治理方案.结果表明：松滋口枯水期的流量主要来自西支.在1960-2019年间,枯水期西支分流量呈现三峡大坝蓄水运行前后从下降趋势转变为显著上升趋势,而东支分流量在下荆江裁弯后至今基本处于断流状态,下荆江裁弯、葛洲坝运行及三峡大坝蓄水运行是其分流量变化的主要诱因.根据建立分流量与水位差（干流水位与河底高程）的回归关系,模拟出在松滋口西东支现有河道的基础上,河床高程分别下降1 m与2.5 m左右,其分流量可达到或接近1960s分流量水平,有助于缓解区域水资源与环境生态问题. 相似文献
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系统解析长江中游河湖交汇区域航道水深资源的变化,可支撑“黄金航道”的可持续发展。本研究以洞庭湖-荆江交汇段为对象,研究洞庭湖分汇区域水沙条件、荆江河段滩槽演变与河湖交汇段航道水深资源的关系。研究表明:三峡工程运行以来,洞庭湖三口分流量和分沙量延续了三峡工程运行前的减少态势,伴随洞庭湖分流量减少,相对增加的长江干流径流量增强了河床冲刷强度,反馈使得洞庭湖三口分流量和分沙量均处于较低值;荆江河段河床冲刷给航道尺度提升奠定了有利基础,河湖分汇区域不满足4.5 m×200 m(水深×宽度)的长度为12.6 km,占荆江河段碍航总长度的68.35%。碍航驱动机制上:松滋口分流区段(枝城-昌门溪)的4.5 m水槽贯通但宽度不足200 m,汊道分流关系不稳定及洲滩萎缩制约航道条件稳定,枯水位下降及“坡陡流急”现象仍然严峻,不利于航道条件保障及船舶安全航行;太平口分流区段水位下降、洲滩萎缩、汊道交替发展使得枯水航路不稳定或水深不足4.5 m;藕池口分流区域的洲滩崩退、洲滩冲刷引起的向下游泥沙输移,碍航表现为航宽不足200 m或出现水深不足4.5 m的浅滩;洞庭湖入汇影响区段(熊家洲-城陵矶)受弯道冲淤... 相似文献
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湖泊生态水位是维持湖泊生态系统健康的重要因素.基于洞庭湖城陵矶、杨柳潭、南咀3个水文站1959-2016年日平均水位序列进行分析,采用Mann-Kendall法、累积距平法和滑动T检验法综合确定洞庭湖水位变异时间节点,结合生态水位年内展布法以及IHA-RVA法,计算分析湖泊最小和适宜生态水位,并且采用Tennant法进行合理验证,在此基础上对水文变异前、后湖泊生态水位保障度进行研究.研究结果表明:(1)洞庭湖城陵矶和杨柳潭水文站年均水位呈上升趋势,而且城陵矶站水位上升趋势显著,南咀站年均水位呈显著下降趋势.(2)洞庭湖3个典型水文站水位年际变化突变年份为2003年,突变年份基本上与三峡工程蓄水时间相符.(3)城陵矶、南咀和杨柳潭年均最小生态水位分别为21.41、28.95和27.84 m,分别占多年平均水位的86.3%、95.9%和95.7%,城陵矶、南咀和杨柳潭年均适宜生态水位分别为23.29、29.51和28.36 m,分别占多年平均水位的93.9%、97.8%和97.5%,生态水位计算结果考虑了天然湖泊水位年内丰枯变化,满足了湖泊生态目标需求.(4)洞庭湖最低生态水位保障程度较高,基本能达到80%以上,但适宜生态水位保障程度相对较低,其中2003年以后洞庭湖10月和11月生态水位保障程度显著下降,与上游水利工程蓄水有关,建议在此期间采取调度措施适当增加洞庭湖水量,以保障湖泊生态系统的健康与生物多样性. 相似文献
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摄食栖息地面积是反映越冬水鸟生存空间的直接指标,三峡水库运行后洞庭湖枯水期水文节律出现新的变化,给越冬水鸟摄食栖息地造成的影响尚不明确.为定量描述三峡水库枯水期不同出库流量对洞庭湖越冬水鸟摄食栖息地的影响,以洞庭湖典型的珍稀越冬水鸟——白鹤(Grus leucogeranus)为指示性候鸟,以白鹤摄食对栖息地水深需求作为关键生态因子,建立白鹤摄食对水深需求的栖息地适宜度模型.构建涵盖长江干流、三口河系、洞庭湖及其四水尾闾河段的江湖一体化耦合水动力模型,实现栖息地水动力分布特征的精确模拟.在此基础上耦合栖息地适宜度模型和水动力模型,建立了面向白鹤摄食对三峡水库出库流量需求的物理栖息地模型,量化不同出库流量对应的白鹤摄食栖息地加权可利用面积,定量分析水库运行对白鹤摄食栖息地面积的影响.结果表明:1月中旬三峡水库不同出库流量下洞庭湖白鹤潜在摄食栖息地面积保持稳定并随出库流量的增加呈增大趋势,维持在101.40~121.84 km2之间,其中东洞庭湖摄食栖息地面积在7.49~9.86 km2之间,南洞庭湖(含横岭湖)摄食栖息地面积在47.37~60.34 km2之间,西洞庭湖摄食栖息地面积在46.54~51.64 km2之间.不同湖区摄食栖息地面积随着三峡水库出库流量的增加均呈增大的趋势,说明三峡水库枯水期补水调度对于维持栖息地面积具有重要作用.较三峡水库运行前相比,白鹤摄食栖息地面积最大增加20.44 km2,对应的增幅为20.16%.成果明晰了三峡水库运行对洞庭湖白鹤摄食栖息地面积的影响规律,可为通过三峡水库补水调度改善洞庭湖越冬水鸟摄食栖息地生境提供理论基础. 相似文献
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洞庭湖是我国第二大淡水湖,与长江连通,在防洪抗旱和湿地生态保护等方面具有重要的现实意义.采用Terra/MODIS L1B遥感数据,提取了2000-2012年洞庭湖水面面积,结合同期城陵矶水位观测数据,建立了城陵矶水位与洞庭湖水面面积的绳套关系曲线.分析结果表明:2000-2012年间,洞庭湖水面面积呈现总体减少的趋势;在季节上表现为规律性的涨落,具有明显的涨(4-6月)-丰(7-9月)-退(10-12月)-枯(1-3月)的水文特征;在空间格局上表现为由湖体中心向外扩张,随后由外向湖体中心逐渐收缩的变化过程;洞庭湖水面面积与城陵矶水位之间具有较高的相关性,但不同时期的相关系数存在一定的差异:枯水期二者相关性较低,丰水期相关性最高,涨水期和退水期相关性较高;这种差异与各个时期的主导因素不同有关,长江来水对枯水期、丰水期的绳套关系影响较大,其中东洞庭湖最为明显;不论丰水年(2002年)或干旱年(2011年),洞庭湖水面面积变化与城陵矶水位之间的相关性均较高.研究结果对于深入认识江湖关系的宏观复杂性、长江中下游地区以及洞庭湖水域洪涝灾害的预防和治理都具有积极的意义. 相似文献
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水利工程兴建后洞庭湖径流与泥沙的变化 总被引：6，自引：6，他引：6
本文根据1951—1988年洞庭湖及其入湖河流的水文泥沙资料,研究大型水利工程兴建后洞庭湖径流与泥沙的变化。研究表明,近40年来洞庭湖的径流量减少了29.2％,输沙量减少了48.7％。引起水沙变化的主要原因是荆江四口分流河床的淤积,使荆江入湖的径流量与输沙量减少。1966—1972年下荆江三个弯道裁弯取直,使荆江河床下切,导致荆江及其分流水位的下降,也促使荆江分流的流量与输沙量的减少。40年来洞庭湖水流变化的趋势对洞庭湖、江汉平原与长江中下游的防洪较为有利。 相似文献
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三峡澎溪河回水区高水位期间高阳平湖总磷模型 总被引：2，自引：1，他引：1
三峡水库"蓄清排浑"的调度运行方式使得冬季高水位期间近岸消落带受淹.消落带氮、磷等营养物受淹后向水体中释放与积累对冬末初春的水华将可能具有重要贡献.构建高水位时期澎溪河高阳平湖总磷收支模型,定量分析高水位期间总磷的收支途径、累积量以及累积磷的主要来源.结果表明:蓄水期,由于蓄水水位升高和顶托而导致大量磷积累;稳定期,磷收支变幅较小,总体趋于平缓;水华期,前期积累的磷被大量消耗,形成水华.淹没消落带磷释放是冬季高水位时期高阳平湖总磷的主要来源,蓄水期所淹没大量消落带所释放的磷为冬季末水华暴发提供条件.研究结果为后续定量分析磷形态的转化和分配奠定重要基础. 相似文献
10.
三峡工程蓄水对洞庭湖水情的影响格局及其作用机制 总被引：13，自引：12，他引：1
三峡工程建成投入运行后,汛末蓄水将使坝下河湖水情发生变化,长江中下游秋季来水减少成为常态.为客观分析三峡蓄水对洞庭湖水情的影响分量、空间格局及其作用机制,选取三峡工程典型的蓄水过程,运用长江中游江湖耦合水动力学模型计算了因上游来水变化引起的洞庭湖水情时空变化.结果表明:1)三峡汛末蓄水对洞庭湖水位影响具有明显的"北高南低,东强西弱"的格局,即东洞庭湖最为显著、南洞庭湖东部和西洞庭湖北部次之,南洞庭湖西部和西洞庭湖南部最小.2)洲滩湿地受蓄水影响最明显的主要为东洞庭湖、南洞庭湖和湖泊洪道两侧的条带状洲滩.3)三峡蓄水对洞庭湖水位的影响机制有二:长江干流水位快速消落加速湖泊水体下泄以及削减长江三口分流补给湖泊的水量. 相似文献
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Identifying flood seasonality is critical in hydrologic applications as well as water resources management. We develop an entropy-based method (EBM) for identifying flood seasonality and partitioning the entire flood season into multiple sub-seasons. The performance of the proposed EBM is evaluated using a Monte Carlo simulation test and compared with current methods. The Three Gorges Reservoir (TGR) basin in the Yangtze River is selected as a case study to test the applicability of the proposed method. Results of Monte Carlo simulation test demonstrate that the EBM performs better than the probability change-point method and the improved relative frequency method with less bias and higher efficiency. The case study results illustrate that the EBM can appropriately divide the entire flood season of the TGR into pre-flood season (from June 1st to June 20th), main-flood season (from June 21th to September 10th) and post-flood season (from September 11th to September 30th). The flood limited water levels (FLWL) in these three sub-seasons can then be derived, which are 150 m, 145 m and 149 m, respectively. Compared with conventional operation rule, the seasonal FLWL scheme can generate more hydropower (0.93 billion KWh) annually with a reliability of 99.86%. Therefore, it is meaningful to divide the entire flood season into three sub-seasons and apply seasonal FLWL for TGR operation. 相似文献
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XuejunSHAO HongWANG ZhaoyinWANG 《国际泥沙研究》2005,20(2):102-108
Sediment supply to the lower Jingjiang River will be subject to substantial reduction after the impoundment of the Three Gorges Reservoir, which could result in an excess of carrying capacity and serious bank erosions in the downstream alluvial channel, threatening the bank protection works and the safety of the Jingjiang Dyke. This paper presents a summary of research works concerning the fluvial processes in the lower Jingjiang River and the possible impact of the Three Gorges Reservoir impoundment on the variation of its channel pattern. Three different predictions have been put forward by researchers: 1) the Jingjiang River will evolve towards a more sinuous, meandering channel pattern, with extensive bank erosion taking place along the river; 2) the river channel will be straightened and broadened because no point bar can be formed due to reduced sediment supply while bank erosion develops in the concave bank, and 3) this river reach will maintain its present channel pattern without significant change, although the sinuosity may be slightly reduced, since: a) the Three Gorges Reservoir mainly intercept sediment particles with sizes larger than 0.025mm, and b) the complex interaction between the Yangtze River and the Dongting Lake helps to reduce the negative effect of channel erosion through certain self-adjusting mechanism in fluvial processes. Discrepancy between these predictions shows that further research efforts are needed to understand the impact of Three Gorges Reservoir operation on the downstream fluvial processes. Meanwhile, there is an urgent need to closely monitor future development in the fluvial processes of the Jingjiang River and its influence on the safety of the Jingjiang Dykes. 相似文献
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《国际泥沙研究》2015,(3)
In this article,the shrinking of Dongting Lake and its progressively weakening connection with the Yangtze River and their impact on flooding before and after the implementation of the Three Gorges Project are analyzed.In recent decades,human activity combined with natural processes has altered the flow of the middle reach channel of the Yangtze River and interfered with its connection with Dongting Lake.This has resulted in progressively more frequent flooding in the area.This study uses hydrological data to analyze the annual maximum discharge and annual maximum stage development of the middle reach of the Yangtze River and Dongting Lake.In recent decades before the Three Gorges Project became operational in 2003,the annual maximum discharge and the maximum stage recorded in the middle reach of the river downstream of Dongting Lake had increased,a result of the weakening of the flood regulation function of Dongting Lake;the annual maximum stage at Luoshan station(downstream,close to the confluence of the Yangtze River and Dongting Lake) had risen by about 2.0 m during 1955-2005,(1.5 m attributed to annual maximum discharge and 0.5 m to river channel deposition).Observational data recorded after the Three Gorges Project was put into operation in 2003,it can be seen that deposition in the Dongting Lake has nearly ceased and the lake's connection with the Yangtze River is stable.It is evident that the flood regulation function of Dongting Lake will continue,and that during the lifetime of the Three Gorges Project,the flood situation in the middle reach of the Yangtze River and Dongting Lake will remain stable. 相似文献
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选择1979-2016年间多时期、多类型、多光谱遥感数据，分析评价洞庭湖区内湖近40年的面积变化.结果表明，最近40年洞庭湖区内湖面积保持相对稳定，丰水期间呈上升趋势，枯水期间波动下降，2016年内湖总面积比1980s初减少3.94%.随着湖泊面积增加，湖泊水面面积变化的比例和幅度逐渐减小，大型湖泊（>10 km2）和中型湖泊（5~10 km2）面积相对稳定，小型内湖（<5 km2）面积变化尤为剧烈.内湖水面面积主要受降雨、蒸发等气候因素和生产生活取水、防洪排涝和退田还湖等人为活动调控.1980-2000年和2001-2015年两个时期，洞庭湖区多年平均降雨量呈现不同程度的下降趋势，多年平均蒸发量明显上升.三峡工程运行后，三口分流衰减，但水资源需求量不断增长，退田还湖和留蓄雨洪作为水资源使得丰水期间内湖水面面积增长，气候变化和水资源开发利用导致枯水期水面面积趋于减少.有必要加强洞庭湖区内湖的研究和保护，适当退田还湖提高湖泊率，优化三口水系格局，实施河湖水系连通工程，缓解洞庭湖区季节性水资源紧张问题. 相似文献
17.
ABSTRACTThe operation of the Three Gorges Reservoir (TGR) affects the evolution of the interactions between the Yangtze River and Dongting Lake in China and water diversions from the river, which are essential to water resources management in this large river–lake system. Due to the lack of up-to-date and detailed channel topographic/bathymetric data, a simplified flow model based on rating curves was developed to simulate discharges in the river system, and to further quantify and differentiate the contributions of river erosion and flow regulation of the TGR at a seasonal scale. The results indicate that the effect of channel alteration counteracts the effect of reservoir regulation in the high-flow periods. The impacts of TGR regulation on water diversions for both pre- and post-flood seasons were significant, but no obvious changes in the discharge diversion ratios were observed on an annual time scale. 相似文献