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Temporal and spatial variation of water stable isotopes (18O and 2H) in the Kaidu River basin,Northwestern China 
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下载免费PDF全文 Water resources are the most critical factors to ecology and society in arid basins, such as Kaidu River basin. Isotope technique was convenient to trace this process and reveal the influence from the environment. In this paper, we try to investigate the temporal and spatial characteristics in stable isotope (18O and 2H) of surface water and groundwater in Kaidu River. Through the water stable isotope composition measurement, spatial and temporal characteristics of deuterium (δ2H) and oxygen 18 (δ18O) were analysed. It is revealed that (1) comparing the stream water line with the groundwater line and local meteorological water line of Urumqi City, it is found that the contribution of precipitation to surface water in stream runoff is the main source, whereas the surface water is the main source of groundwater. Groundwater is mainly drainage of surface runoff in the river; (2) in the main stream of Kaidu River, the spatial variability of river water showed a ‘heavier‐lighter‐heavier’ change along with the main stream for δ18O, and temporal variability showed higher in summer and lower in winter; (3) the δ18O and δ2H values of groundwater samples ranged from ?11.36 to ?7.97‰ and ?73.45 to ?60.05‰, respectively. There is an increasing trend of isotopic values along the groundwater flow path. The seasonal fluctuation of δ18O is not clear in most samples. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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新疆博斯腾湖水盐变化及其影响因素探讨 总被引：11，自引：5，他引：11
在博斯腾湖水文和水化学实测资料的基础上，研究了博斯腾湖水盐的年际和年内变化。近40年来，水质年际变化经历了好→中→差→中的过程；年内变化与区内最大补给源开都河不同季节河流来水量变化以及湖周农田排盐水等因素直接相关，而湖水的矿化度与水位变化呈负相关。对湖水主要离子含量变化特点和湖区矿化度变化规律的研究表明，湖水补给源及湖水循环状况是影响湖水水质变化的主要因素。 相似文献
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分析了1951-2011年博斯腾湖历史水位和湖水矿化度的动态变化特征,解析了博斯腾湖水量与水质对气候变化的响应及未来变化趋势.结果表明,博斯腾湖水位在60年内经历了两个突变时期,突变时间分别为1974年和1994年,湖水矿化度也相应地呈现了三个动态变化阶段,水量与水位呈极显著负相关,但水质变化滞后于水位变化1年;流域气温呈显著增加趋势,气温升高的突变时间为1993年,与开都河出山口径流突变时间一致,但降水变化不显著;1993年前,博斯腾湖水量主要受气温和人类活动双重影响,1993年后博斯腾湖水量主要受气温的显著影响,气温主要通过改变入湖水量及湖区蒸发损耗来调控湖泊水位和水质;未来气温持续升高情景下,博斯腾湖水位将面临降低趋势,水质也将有恶化趋势.因此,为合理开发利用博斯腾湖水资源,减少水资源无效损耗,抑制水质恶化趋势,确保流域可持续发展,建议将博斯腾湖调水时间集中在5-9月,并严格控制孔雀河流域工农业用水量及工农业、生活污染源,减少污水排放量,减少周边地下水开发量. 相似文献
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气候背景下冰川在博斯腾湖水量平衡中的作用 总被引：2，自引：1，他引：2
基于博斯腾湖水量平衡关系,对博斯腾湖水量变化做了分析,认为博斯腾湖近年水位的显著变化与占其入湖水量85%的开都河流量变化有直接关系．冰川作为开都河上游重要的水资源形势,造就了开都河稳定的基流．部分冰川在近20年全球和区域气候变化影响下发生了较大退缩,消退的冰雪直接补给了开都河径流,对开都河连年丰水起了重要作用．随着相对海拔较低的中小冰川的退缩,冰益变薄雪线升高,冰雪储量减少,冰川对气温升高的敏感性开始降低,融水补给量可能随之减少,气候变暖所带来的融水补给效应将减弱,最终影响到博斯腾湖的入流补给． 相似文献
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近百年来新疆博斯腾湖初级生产力的变化 总被引：2，自引：1，他引：1
本研究选择新疆博斯腾湖不同区域进行沉积岩芯采集.在210Pb、137Cs定年的基础上,利用漫反射光谱分析了湖泊沉积物中叶绿素a的含量,结合沉积速率、烧失量以及开都河的径流量记录等,探讨近百年来湖泊初级生产力的变化.结果表明:开都河的径流量变化对博斯腾湖沉积速率与生产力演化有一定影响,而人类活动干扰则是影响湖泊初级生产力演化的主要原因.1950s开始的新疆第一次大规模开垦活动导致了湖泊的沉积速率及初级生产力开始上升.沉积物的沉积速率以及叶绿素a的沉积通量在1970年左右出现最高值后下降,这与新疆的第二次大规模垦荒有关,同时,周边地区盐碱地除盐方式的改变对湖泊的生态环境变化也有很大影响.从1980s至今,由于流域内人类活动干扰增强,沉积物中的叶绿素a浓度逐渐增加,湖泊初级生产力呈上升的趋势. 相似文献
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Seepage meters modified for use in flowing water were used to directly measure rates of exchange between surface and subsurface water in a gravel‐ and cobble bed river in western Pennsylvania, USA (Allegheny River, Qmean = 190 m3/s) and a sand‐ and gravel‐bed river in Colorado, USA (South Platte River, Qmean = 9·7 m3/s). Study reaches at the Allegheny River were located downstream from a dam. The bed was stable with moss, algae, and river grass present in many locations. Median seepage was + 0·28 m/d and seepage was highly variable among measurement locations. Upward and downward seepage greatly exceeded the median seepage rate, ranging from + 2·26 (upward) to ? 3·76 (downward) m/d. At the South Platte River site, substantial local‐scale bed topography as well as mobile bedforms resulted in spatial and temporal variability in seepage greatly in exceedence of the median groundwater discharge rate of 0·24 m/d. Both upward and downward seepage were recorded along every transect across the river with rates ranging from + 2·37 to ? 3·40 m/d. Despite a stable bed, which commonly facilitates clogging by fine‐grained or organic sediments, seepage rates at the Allegheny River were not reduced relative to those at the South Platte River. Seepage rate and direction depended primarily on measurement position relative to local‐ and meso‐scale bed topography at both rivers. Hydraulic gradients were small at nearly all seepage‐measurement locations and commonly were not a good indicator of seepage rate or direction. Therefore, measuring hydraulic gradient and hydraulic conductivity at in‐stream piezometers may be misleading if used to determine seepage flux across the sediment‐water interface. Such a method assumes that flow between the well screen and sediment‐water interface is vertical, which appears to be a poor assumption in coarse‐grained hyporheic settings. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Unlike rivers in humid regions, dryland rivers typically exhibit reduced flow in the downstream direction as a result of transmission losses, which include seepage of streamflow into the aquifer, evaporation, and transpiration. However, much remains to be learned about the nature of the exchange between surface water and groundwater in these landscapes, especially in terms of spatial and temporal variability. Our study focused on streambank seepage and groundwater flow in the alluvial aquifer, specifically on answering questions such as: Is there seasonal variability in seepage losses? Is seepage permanently lost? Can losses be reduced by killing riparian vegetation? To better understand the magnitude, variability, and fate of streambank seepage, we assessed river stages, groundwater hydraulic gradients, and groundwater flow paths at two sites along a reach of the Pecos River, a dryland perennial river in West Texas. We found that along this reach the river was losing water to the aquifer even under low‐flow conditions; but seepage was controlled by a number of different mechanisms. Seepage increased not only during high‐flow events but also when the groundwater level was declining owing to long periods of no irrigation release. Tamarix (saltcedar) control did not affect hydraulic gradients nor reduce streambank seepage and given that this reach of the Pecos River is a losing one, streamflow will not be enhanced by controlling saltcedar. These findings can be used to improve basic conceptual models of dryland river systems and to predict hydrologic responses to changes in the timing and magnitude of streamflows and to riparian vegetation management. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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The planning and management of water resources in the Shiyang River basin, China require a tool for assessing the impact of groundwater and stream use on water supply reliabilities and improving many environment‐related problems such as soil desertification induced by recent water‐related human activities. A coupled model, integrating rule‐based lumped surface water model and distributed three‐dimensional groundwater flow model, has been established to investigate surface water and groundwater management scenarios that may be designed to restore the deteriorated ecological environment of the downstream portion of the Shiyang River basin. More than 66% of the water level among 24 observation wells have simulation error less than 1·0 m. The overall trend of the temporal changes of simulated and observed surface runoff at the Caiqi gauging station remains almost the same. The calibration was considered satisfactory. Initial frameworks for water allocation, including agricultural water‐saving projects, water diversion within the basin and inter‐basin water transfer, reducing agricultural irrigation area and surface water use instead of groundwater exploitation at the downstream were figured out that would provide a rational use of water resources throughout the whole basin. Sixteen scenarios were modelled to find out the most appropriate management strategies. The results showed that in the two selected management options, the groundwater budget at the Minqin basin was about 1·4 × 108 m3/a and the ecological environment would be improved significantly, but the deficit existed at the Wuwei basin and the number was about 0·8 × 108 m3/a. Water demand for domestic, industry and urban green area would be met in the next 30 years, but the water shortage for meeting the demand of agricultural water use in the Shiyang River basin was about 2·2 × 108 m3/a. It is suggested that more inter‐basin water transfer should be required to obtain sustainable water resource use in the Shiyang River basin. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献