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Keisuke Hoshikawa Yoichi Fujihara Sokly Siev Seiya Arai Takashi Nakamura Hideto Fujii Ty Sok Chihiro Yoshimura 《水文研究》2019,33(21):2745-2758
Large, shallow‐water lakes located on floodplains play an important role in creating highly productive ecosystems and are prone to high concentrations of suspended solids due to sediment resuspension. In this study, the aim was to determine the dominant processes governing the total suspended solid (TSS) concentration at the water surface in Tonle Sap Lake, Cambodia, which is a large, shallow‐water lake. Satellite remotely sensed daily reflectance data from 2003 to 2017 were used. Seasonal changes in TSS concentration indicated that bottom sediment resuspension during dry seasons was mostly caused by wind and the TSS concentration was closely correlated with the water depth of the lake. The TSS concentration during flood periods was controlled by both wind and inflow currents from the Tonle Sap River. Additionally, we confirmed that surface/subsurface flow with a low TSS concentration from forests on the floodplain lowered the TSS concentration year round, except during August and September. This fact implied that the floodplain forest area decrease may increase the lake TSS concentration. An analysis of the long‐term changes in TSS indicated that a decrease in the water level during flood periods resulted in the high TSS concentrations observed during the subsequent dry periods. Therefore, climate change and water resource development, which are likely to cause water level reductions in the Mekong River during flood periods, may increase the TSS concentration in Tonle Sap Lake, particularly during the dry season. 相似文献
3.
The Mekong Basin in southeast Asia is facing rapid development, impacting its hydrology and sediment dynamics. Although the understanding of the sediment transport rates in the Mekong is gradually growing, the sediment dynamics in the lower Mekong floodplains (downstream from Kratie) are poorly understood. The aim of this study is to conduct an analysis to increase the understanding of the sediment dynamics at the Chaktomuk confluence of the Mekong River, and the Tonle Sap River in the Lower Mekong River in Cambodia. This study is based on the data from a detailed field survey over the three hydrological years (May 2008–April 2011) at the two sites (the Mekong mainstream and the Tonle Sap River) at the Chaktomuk confluence. We further compared the sediment fluxes at Chaktomuk to an upstream station (i.e. Mukdahan) with longer time series. Inflow sediment load towards the lake was lower than that of the outflow, with a ratio on average of 84%. Although annually only a small amount of sediment load from the Tonle Sap contributes to the delta (less than 15%), its share is substantial during the February–April period. The annual sediment load transport from the confluence to the delta in 2009 and 2010 accounted for 54 and 50 Mt, respectively. This was on average only 55% of the sediment fluxes measured at Mukdahan, a more upstream station. Furthermore when compared to sediment loads further downstream at the Cambodia–Vietnam border, we found that the suspended sediment flux continued to decline towards the South China Sea. Our findings thus indicate that the sediment load to the South China Sea is much lower than the previous estimate 150–160 Mt/yr. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
4.
Aifang Chen Junguo Liu Matti Kummu Olli Varis Qiuhong Tang Ganquan Mao Jie Wang Deliang Chen 《水文研究》2021,35(9):e14327
Tonle Sap Lake (TSL) is one of the world's most productive lacustrine ecosystems, driven by the Mekong River's seasonal flood pulse. This flood pulse and its long-term dynamics under the Mekong River basin's (MRB) fast socio-economic development and climate change need to be identified and understood. However, existing studies fall short of sufficient time coverage or concentrate only on changes in water level (WL) that is only one of the critical flood pulse parameters influencing the flood pulse ecosystem productivity. Considering the rapidly changing hydroclimatic conditions in the Mekong basin, it is crucial to systematically analyse the changes in multiple key flood pulse parameters. Here, we aim to do that by using observed WL data for 1960–2019 accompanied with several parameters derived from a Digital Bathymetry Model. Results show significant declines of WL and inundation area from the late 1990s in the dry season and for the whole year, on top of increased subdecadal variability. Decreasing (increasing) probabilities of high (low) inundation area for 2000–2019 have been found, in comparison to the return period of inundation area for 1986–2000 (1960–1986). The mean seasonal cycle of daily WL in dry (wet) season for 2000–2019, compared to that for 1986–2000, has shifted by 10 (5) days. Significant correlations and coherence changes between the WL and large-scale circulations (i.e., El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Indian Ocean Dipole (IOD)), indicate that the atmospheric circulations could have influenced the flood pulse in different time scales. Also, the changes in discharge at the Mekong mainstream suggest that anthropogenic drivers may have impacted the high water levels in the lake. Overall, our results indicate a declining flood pulse since the late 1990s. 相似文献
5.
倒灌是发生在湖泊与周围水体交汇处的一个重要物理过程,对湖泊水文水动力与水环境带来严重影响或干扰,进而对湖泊水质产生重要的影响或控制作用.本文采用统计方法和二维水动力-粒子示踪耦合模型来分析倒灌物理成因、倒灌发生判别与指示以及倒灌对鄱阳湖水文水动力的影响.统计表明,流域"五河"入湖径流、长江干流径流情势以及两者叠加作用均是倒灌的影响因素,但长江干流径流情势是影响或者控制倒灌频次与倒灌强度的主要因素."五河"来水与长江干流的流量比可用来判别与指示倒灌发生与否.当流量比低于约5%时,倒灌可能发生且最大发生概率可达25%;当流量比高于10%时,倒灌发生概率则低于2%.水动力模拟结果表明,倒灌对湖区水位与流速的影响向湖区中上游逐渐减弱,湖泊水位和流速受影响最为显著的区域主要分布在贯穿整个湖区的主河道,而浅水洪泛区的水位和流速则受倒灌影响相对较小.倒灌使得湖泊空间水位提高约0.2~1.5 m,湖泊主河道的流速增加幅度可达0.3 m/s.粒子示踪结果表明,倒灌导致湖区水流流向转变约90°~180°,倒灌导致的水流流向变化能够使湖区大部分粒子或物质向上游迁移约几千米至20 km,且粒子在下游主河道的迁移距离要明显大于中上游洪泛区. 相似文献
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受地表河湖系统水情变化干扰,高度动态和异质性的洪泛区地下水文对河湖水资源、水污染以及生态环境功能等方面具有重要影响和贡献。鄱阳湖洪泛区湿地在长江中下游具有重要区位优势和研究特色,但变化环境下其水动力特征和水量交换情况等仍存在许多不确定性。本文以鄱阳湖典型洪泛区为研究区,采用地下水流二维数值模型,开展了洪泛区地表地下水转化作用与水量变化的模拟研究。结果表明,鄱阳湖季节性水位变化很大程度上决定了主湖区与周边地下水之间的动态补排模式,即洪泛区地下水补给湖泊主要发生在枯水和退水时期,而湖泊补给地下水主要发生在涨水和高洪水位时期。一般情况下,整个洪泛区地下水位与湖水位的年内变化态势基本一致,主湖区附近的地下水位年内变幅较大,而大部分洪泛区的地下水位变幅相对较小。北部地下水流速明显大于南部,主湖区附近地下水流速明显大于洪泛区,地下水流速基本小于1～2 m/d。水均衡分析发现,洪泛区地下水系统以接受降雨输入（52%）和主湖区补给（39%）为主,以地下水蒸发输出（72%）和向湖排泄（24%）为主,但补给主要发生在春、夏季,而排泄则发生在秋、冬季。地形地貌对洪泛区地下水位分布以及流速场演化具有主控作用,... 相似文献
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The level of Lake Tana, Ethiopia, fluctuates annually and seasonally following the patterns of changes in precipitation. In this study, a mass balance approach is used to estimate the hydrological balance of the lake. Water influx from four major rivers, subsurface inflow from the floodplains, precipitation, outflow from the lake constituting river discharge and evapotranspiration from the lake are analysed on monthly and annual bases. Spatial interpolation of precipitation using rain gauge data was conducted using kriging. Outflow from the lake was identified as the evaporation from the lake's surface as well as discharge at the outlet where the Blue Nile commences. Groundwater inflow is estimated using MODular three‐dimensional finite‐difference ground‐water FLOW model software that showed an aligned flow pattern to the river channels. The groundwater outflow is considered negligible based on the secondary sources that confirmed the absence of lake water geochemical mixing outside of the basin. Evaporation is estimated using Penman's, Meyer's and Thornwaite's methods to compare the mass balance and energy balance approaches. Meteorological data, satellite images and temperature perturbation simulations from Global Historical Climate Network of National Oceanographic and Atmospheric Administration are employed for estimation of evaporation input parameters. The difference of the inflow and outflow was taken as storage in depth and compared with the measured water level fluctuations. The study has shown that the monthly and annually calculated lake level replicates the observed values with root mean square error value of 0·17 and 0·15 m, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
8.
Marco Petitta Gabriele Scarascia Mugnozza Maurizio Barbieri Gianluca Bianchi Fasani Carlo Esposito 《水文研究》2010,24(24):3510-3520
This study addresses the influence of landslide dams on surface water drainage and groundwater flow. In the study area of Scanno Lake and Sagittario River (Central Italy), a limestone rockslide‐avalanche formed a lake, which has an outlet that is occasionally active, showing infiltration into the rockslide dam. Several springs are present at the lake's base and are partly fed by seepage through the rockslide debris. Piezometric surveys, discharge measurements, pumping tests and chemical analyses are tools used to build a conceptual model of the groundwater flow and to evaluate the flow through the rockslide debris. Seasonal water isotopic signatures validate the assumed model, showing a mixing of infiltration recharge and groundwater seepage throughout the rockslide debris. Various recharge areas have been found for springs, pointing out those directly fed by the rockslide debris aquifer. Hypotheses about seasonal groundwater mixing between the regional carbonate aquifer and the rockslide debris aquifer are supported by isotope results. Seasonal changes in groundwater table level due to recharge and surface losses from seasonal outlet have been correlated with isotopic groundwater composition from the rockslide debris aquifer and the downstream springs; this relationship highlights the role of the rockslide dam body on the hydrodynamics of the studied area. Relationships between surface waters and groundwater in the area have been completely understood on the basis of water isotopic fingerprinting, finally obtaining a complete evaluation of groundwater renewable resources and its regimen. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
9.
U. Saravana Kumar Noble Jacob S. V. Navada S. M. Rao Rm. P. Nachiappan Bhishm Kumar J. S. R. Murthy 《水文研究》2001,15(3):425-439
Environmental isotopes (δ18O, δD and 3H) were used to understand the hydrodynamics of Lake Naini in the State of Uttar Pradesh, India. The data was correlated with the in situ physico‐chemical parameters, namely temperature, electrical conductivity and dissolved oxygen. The analysis of the data shows that Lake Naini is a warm monomictic lake [i.e. in a year, the lake is stratified during the summer months (March/April to October/November) and well mixed during the remaining months]. The presence of a centrally submerged ridge inhibits the mixing of deeper waters of the lake's two sub‐basins, and they exhibit differential behaviour. The rates of change of isotopic composition of hypolimnion and epilimnion waters of the lake indicate that the water retention time of the lake is very short, and the two have independent inflow components. A few groundwater inflow points to the lake are inferred along the existing fractures, fault planes and dykes. In addition to poor vertical mixing of the lake due to the temperature‐induced seasonal stratification, the lake also shows poor horizontal mixing at certain locations of the lake. The lake–groundwater system appears to be a flow‐through type. Also, a tritium and water‐balance model was developed to estimate the water retention time of well‐mixed and hydrologically steady state lakes. The model assumes a piston flow of groundwater contributing to the lake. The developed model was verified for (a) Finger Lakes, New York; (b) Lake Neusiedlersee, Austria; and (c) Blue Lake, Australia based on literature data. The predicted water retention times of the lakes were close to those reported or calculated from the hydrological parameters given in the references. On application of this model to Lake Naini, a water retention time of ～2 years and age of groundwater contributing to the lake ～14 years is obtained. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
10.
流域内地表水、土壤水和地下水等水储量组分相互作用和影响,共同构成了陆地水储量(TWS)的动态变化格局。本文以GRACE卫星数据为基准,利用GLDAS数据解析1960-2019年鄱阳湖“五河”流域TWS的时空变化特征及各组分对其变化的贡献,采用相关分析方法分析TWS对降水的滞后响应关系,并进一步采用多元线性回归分析方法探究了“五河”流域TWS及各组分对鄱阳湖主湖区水量的影响。结果表明:“五河”流域年TWS在1960-2011年(P1)以-0.07 mm/a的下降,而在2012-2019年(P2)以3.37 mm/a的速率上升。相较于P1阶段,P2阶段春、夏季TWS盈余增强,秋、冬季TWS亏损减弱。春、夏季流域西部TWS变化逐渐由地表水转变为地下水储量主导,流域东部TWS变化主要由地下水储量主导;秋、冬季流域TWS变化主要为地下水储量主导,且地表水对TWS变化的贡献减弱。流域TWS对降水变化的响应滞时呈现夏、秋季短(1个月)而冬、春季长(3~6个月)的季节模式。地下水储量和土壤水对TWS变化的贡献增加会延长TWS对降水的响应滞时,而地表水对响应滞时起相反的作用。“五河”流域TWS与鄱阳湖主湖区水量具有显著的正相关性,地表水和地下水储量增加对湖区水体的增长具有正向作用,而土壤水增加对湖区水体的增长具有反向作用。本研究解析了近六十年鄱阳湖“五河”流域陆地水储量的变化及其对主湖区水量的影响,可为流域水安全管理提供参考。 相似文献
11.
流域范围内地表水和地下水转化对盐湖成盐元素的运移和富集具有十分重要的意义.本文通过尕斯库勒盐湖盆地内流域水体的水化学和B同位素特征识别了地表水和地下水之间的定量转化关系,在此基础上估算了流域中铀的补给通量.结果表明,流域水体中离子的分异除了蒸发浓缩作用之外,还受重力分异及掺杂作用的影响;上游库拉木勒克萨伊河和阿特阿特坎河水体在出山口附近转入地下并在中游补给地表水和地下水,其补给率分别占48.8%和51.2%,年均补给量分别为1.08×108和1.13×108m3/a;在中游至尾闾盐湖段,阿拉尔河和侧向补给对盐湖卤水的补给率占55.2%,深部水体的补给占44.8%;至少从5.7 ka以来,上游水体对盐湖卤水中铀的补给通量为4.11×103t,在湖积平原黏土沉积带以及祁漫塔格山前局部还原带可能具有较大规模的铀矿.研究结果有助于建立盐湖盆地水循环模式、揭示卤水资源形成机制;同时为尕斯库勒盐湖盆地水资源的高效利用和寻找铀矿提供理论依据和技术支持. 相似文献
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盐分是参与湖泊物质循环的重要成分之一,湖泊盐度增加对湖泊生态系统健康造成了严重的威胁.乌梁素海总溶解性固体（TDS）和盐度均处于较高的水平,为揭示盐分在冰-水-沉积物中的分布及迁移规律,冰封期在乌梁素海7个采样点采集冰、冰下水和不同深度沉积物样品,分析样品的TDS、Na+和Cl-浓度,得到各自在冰-水间浓度的比值,即分配系数K,并对水-沉积物界面Na+和Cl-的扩散通量进行估算.结果显示,TDS、Na+和Cl-在冰-水中分配系数K的均值分别为0.02、0.03和0.01,表明在湖水结冰形成冰盖的过程中,随着冰晶的析出,TDS、Na+和Cl-逐渐在水体中浓缩,水体中Na+和Cl-在浓度梯度驱动力作用下,向沉积物间隙水中扩散,估算其扩散通量均值分别为-229和-676 mg/（m2·d）.总之,湖水在冻结过程中,由于冰晶的析出,盐分向冰下水体中迁移,使得盐分浓度在冰下水体中浓缩增加,继而向沉积物中迁移,对湖泊水生态环境构成胁迫. 相似文献
13.
Lake flooding sensitivity to the relative timing of peak flows between upstream and downstream waterways: A case study of Poyang Lake,China 总被引：1，自引：0，他引：1 
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下载免费PDF全文 The relative timing of peak flows (RTPF) from tributaries has significant influence on flood occurrence at their confluence. This study is aimed at (1) analysing the characteristics of the RTPF of the 5 recharging rivers in the Poyang Lake catchment and the Yangtze River during the period of 1960–2012, and (2) employing a physically‐based hydrodynamic model (MIKE 21) to quantify the effects of RTPF on flood behaviour in the Poyang Lake (the largest freshwater lake in China). The results show that short RTPF, or close occurrence of peak flows, triggers flood in the Poyang Lake more easily. More than 75% of total flood events in the study period occurred with RTPF less than 60 days, and more than 55% of the events occurred with RTPF less than 30 days. The hydrodynamic simulation revealed that the date of flood peak in the lake was postponed by 4–7 days and the flood stage raised by 0.69 m because of the delay of peak flows from the upstream rivers/tributaries. On the other hand, earlier start of the Yangtze River peak flow led to flood peak in the lake 6–13 days earlier. Additionally, the duration of high lake water levels was extended by 9–12 days when the RTPF shortened, and the flood hydrograph of the Poyang Lake changed from a flat to a flashy type. These results indicate that an enlarged RTPF between the upstream rivers and the Yangtze River could be an effective way to prevent flood disasters in the Poyang Lake, a method apparently being adopted in the operation of the Three Gorges Dam. The RTPF should be considered and integrated when developing flood prevention and management plans in the Poyang Lake, as well as in other similar regions in the world. 相似文献
14.
古生态记录揭示的长江中下游太白湖生态系统稳态转换过程 总被引：2，自引：2，他引：0
长江中下游浅水湖泊在过去百年内受到强烈的人类活动影响,生态系统状态发生显著的变化,服务功能逐渐丧失.为了更科学有效地管理浅水湖泊,当前迫切需要了解湖泊的生态系统转变过程.以长江中下游典型富营养化浅水湖泊太白湖为例,结合历史资料和监测数据,基于铅铯同位素重建年代序列,利用粒度、地化指标和沉积物中硅藻群落的时间序列数据,对太白湖过去百年间生态系统转变进行分析.基于T检验的STARS法检测硅藻群落的结果显示,有2个稳态转换分别发生在1950s末和1990s末.1950s末太白湖硅藻群落代表的生态系统状态发生了显著突变,这主要归因于由于建闸筑坝造成的水文条件和营养条件的改变;1990s期间的湖泊生态系统整体转变则是由长期营养输入和渔业活动加强导致的生态系统弹性损失引起的.讨论了不同阶段太白湖生态系统主要要素间反馈机制在水文条件改变和营养富集影响下的变化,加深了对人类活动干扰下太白湖生态系统结构变化过程的理解,为建立浅水湖泊系统动力学模型提供基础. 相似文献
15.
Remote-sensing images of Ebinur Lake Basin including six years (1960, 1972, 1990, 2000, 2005 and 2010) were interpreted through RS and GIS. Land use changes in Ebinur Lake Basin during the past five decades were analyzed according to interpretation results. On this basis, effect of land use changes on hydrology and water resources was analyzed. Results show that the land use pattern in Ebinur Lake Basin changed greatly from 1960 to 2010. Cultivated Land and Urban-Rural Construction Land increased, while other landuse types decreased. Most areas were Unused Land. Generally, oasis expanded continuously, but oasis in Ganjiahu Zone at downstream of the Kuitun River Basin reduced to some extent. Runoff of the Kuitun River and Jinghe River increased gradually, but runoff of the Bortala River reduced continuously. Both inflows and lake area declined year by year. The groundwater level dropped significantly and water deteriorated continuously. Due to the decelerating wind blowing, evaporation in the basin reduced accordingly. Hydrology and water resources changes in Ebinur Lake Basin in past five decades were mainly caused by continuous expansion of Cultivated Land and oasis, continuous population growth and hydraulic engineering constructions. However, oasis expansion shall be limited within the carrying capacity of water resources. To maintain ecological security in the basin, it is necessary to determine reasonable oasis area, optimize river system structure, and improve utilization efficiency of water resources. 相似文献
16.
《Water Policy》2000,1(6):587-603
The United States has historically been a strong supporter of coordinated, international water resources studies and planning in Southeast Asia's Lower Mekong River Basin. Since 1975, however, the United States has not contributed to the Mekong Project. Nonetheless, the United States may benefit in several ways by supporting the Mekong River Commission. This paper describes a rationale for renewed US participation in the Mekong Project and identifies several Mekong River Commission Secretariat programs to which the United States could contribute. 相似文献
17.
Ilias Bertahas Elias Dimitriou Ioannis Karaouzas Sofia Laschou Ierotheos Zacharias 《洁净——土壤、空气、水》2006,34(4):349-359
Trichonis Lake is the largest natural freshwater body in Greece with a surface area of 97 km2. It receives pollutants from numerous anthropogenic activities, especially from intensive agricultural practices, urban sewages, stock grazing land and small industries. In this study, hydrologic and chemical parameters are assessed during two periods (1990–1991) and (2001–2002) to evaluate the effects of the climatic changes on phosphorous trends and consequently on the trophic status of Trichonis Lake. Even though large quantities of fertilizers are applied in the lake's catchment, phosphorus loads are still in the permissible level as estimated according to Vollenweider's relationship based on total phosphorus concentration. Due to relatively higher rainfall precipitation during the last years, an increased amount of the phosphorus entering into the lake system is flushed out, thus keeping the trophic status of the lake in oligotrophic levels. In contrast, lower rainfall rates during the first period (1990–1991) have led to the decrease in phosphorus flush out and its detainment into the lake water and sediment resulting to mesotrophic conditions. As the trophic status of the lake is mainly hydrologically dependent and thus unpredictable, effective management plans targeting the elimination of nutrient pollution loadings are necessary. 相似文献
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在复杂湖泊水动力环境作用下,换水周期和传输时间变化直接影响着污染物的迁移和转化.本文运用数值模拟方法,定量研究了季节水情动态下鄱阳湖换水周期和示踪剂传输时间的空间分布.结果表明,不同季节下鄱阳湖换水周期均具有较高的空间异质性,贯穿整个湖区的主河道换水周期约10 d,大多湖湾区的换水周期则长达300多天.尽管不同季节下换水周期空间分布格局几乎相似,但受鄱阳湖水动力场的季节变化影响,夏、秋季的换水周期要明显大于春、冬季.基于换水周期频率分布曲线的统计表明,80%的鄱阳湖区的换水周期约30 d,其余湖区换水周期为几十天至几百天,表明鄱阳湖应该更加确切地描述为一个快速换水和慢速换水同时共存的湖泊系统.鄱阳湖示踪剂传输时间介于4~32 d,夏、秋季的传输时间(11~32 d)约为春、冬季(4~8 d)的4倍,主要与鄱阳湖季节性水情特征及示踪剂的迁移路径有关.本文所获取的换水周期和示踪剂传输时间的时空分布信息可为今后鄱阳湖水质、水环境和生态系统管理和维护等方面提供重要科学参考. 相似文献
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Radwan A. Al‐Weshah 《水文研究》2000,14(1):145-154
The Dead Sea is the lowest spot on Earth. It is a closed saline lake located in the middle of the Jordan Rift Valley between Lake Tiberias and the Red Sea. Its major tributaries are the Jordan River itself and the Dead Sea side wadis. The Dead Sea has a unique ecosystem and its water has curative, industrial and recreational significance. The level of the Dead Sea has been continuously falling since the early 1930s at an average rate of 0·7 m per year. The water level, as of February 1998, is about 410·9 m below mean sea level. In this paper, a water balance model is developed for the Dead Sea by considering different hydrological components of this water balance, including precipitation, runoff, evaporation and groundwater flow. This model is calibrated based on historical levels of the Dead Sea. Different scenarios are investigated, including the proposed Dead Sea–Red Sea Canal. This project is supposed to halt the shrinking of the Dead Sea and restore it to pre‐1950 levels in the next century. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献