, 于心怡, 张飞A review of water issues research in Central Asia
YANGShengtian, YUXinyi, ZHANGFei通讯作者:
收稿日期:2016-07-15
修回日期:2016-11-8
网络出版日期:2017-01-20
版权声明:2017《地理学报》编辑部本文是开放获取期刊文献，在以下情况下可以自由使用：学术研究、学术交流、科研教学等，但不允许用于商业目的.
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1 引言
中亚地区位于亚洲中部,目前中亚地区范围并没有十分准确的界定。在俄语中,前苏联将中亚地区表述为“Middle Asia”,包括哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦和塔吉克斯坦五国;而在英语中,中亚地区使用的名词是“Central Asia”,包括范围更广,有蒙古、中国西部、俄罗斯西伯利亚、伊朗北部、阿富汗、巴基斯坦和印度等国家和地区。在中国一般将伊朗北部、阿富汗、巴基斯坦和印度等国家和地区划为西亚。为了更好地开展相关文献收集和分析,本文按中国分类,中亚地区主要指中亚五国（哈萨克斯坦、乌兹别克斯坦、土库曼斯坦、吉尔吉斯斯坦、塔吉克斯坦）和中国新疆维吾尔自治区（图1）。
显示原图|下载原图ZIP|生成PPT图1中亚地区范围及主要河流
-->Fig. 1Geographical boundary and major rivers of Central Asia
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中亚地区位于东、西、南三方地理交汇点,是联接它们社会、经济和文化交流的节点,历史上商贸聚集,是古丝绸之路的重要地段;第二次世界大战结束后,中亚地区进一步发展成为重要的能源产地。1991年前苏联解体后,各加盟共和国相继独立,政治制度和管理体制发生巨变,加剧了这一地区地缘政治的复杂程度,中亚地区成为全球各种政治力量角逐的敏感地区,是国际社会中最不稳定的地区之一[1]。
中亚地域广阔,河流众多,主要河流有阿姆河、锡尔河、楚河、塔拉斯河、额尔齐斯河、伊犁河、伊希姆河、托博尔河、塔里木河、乌拉尔河、喷赤河、瓦赫什河、泽拉夫尚河、菲尔尼干河和卡拉河等15条,且多为国际河流。但是,由于中亚地区地处欧亚大陆腹地,降水稀少,蒸发量大,导致水资源十分匮乏。近60年来,中亚各国水资源利用经历了从合作到对立的过程：前苏联时期,中亚地区在20世纪60年代开始大规模兴建水利工程;20世纪70-80年代达到高峰,大量的大坝、灌区建设完成,有较为完整的水资源利用总体规划与布局,也有较好的统一管理;但1991年后,随着前苏联解体,以公有制为主体的计划经济转向以私有制为主体的市场经济,社会格局巨变,完全摧毁了原有水资源管理体系。同时由于近年来气候变化,各国之间用水问题日益恶化,中亚地区面临着上游国产水与下游国用水、水资源总量减少与水资源用量增加、工业发电与农业灌溉、能源价格与水资源价格,以及水污染与水环境保护等诸多矛盾,引发了一系列水资源与水环境问题,甚至危及到社会稳定与经济发展。中亚被列为世界上七大水资源争端高发区之一,是国际上水问题十分严重的地区。
当前,国内外十分关注中亚地区水问题研究,Unger-Shayesteh等[2]总结了气候变化对中亚高山地区水循环影响的研究成果;Abdolvand等[3]从地缘政治角度综述了中亚地区水资源利用的合作与发展;Abdullaev等[4]阐述了中亚地区水资源利用的变化历程;Karthe等[1]分析了未来中亚地区水资源利用面临的挑战。这些综述性文章从不同侧面总结了中亚地区水问题研究成果,但仍缺乏从发展历程、研究方法和研究内容等方面的综合分析。为此,本文查阅了2000年以来近15年的中英文文献,从文献数量变化、研究机构、研究方法,以及主要水问题研究等方面,归纳国内外有关中亚地区水问题的主要研究成果,阐述中亚地区水问题研究热点、研究理论与方法,揭示研究发展的趋势。
2 文献统计分析
文献检索时间范围为2000年1月-2016年5月。英文文献主要从Academic Search Premier（ASP）、ScienceDirect（Elsevier）和SpringerLink（Kluwer Online）等数据库中查询,文献检索方式以标题或关键词“Central Asia+water”、“Central Asia+river”或“Central Asia+basin”查询;中文文献主要从万方数据库查询,文献检索方式以标题或关键词“中亚+水”、“中亚+河”或“中亚+流域”查询。共计检索英文文献近160篇,中文文献60余篇,对其中与中亚地区水问题密切相关的105篇英文文献和51篇中文文献进行统计分析,再选择60余篇重点文献进行综述。按照中亚地区水问题的特点,参考国内外水文水资源研究的主要内容,针对每篇文献的研究对象,按水循环过程、水资源状况、流域水环境和跨界河流管理4个研究领域进行分类统计,每个领域涉及中亚地区水问题的不同内容（表1）;同时按照英文文献和中文文献数量、研究方法、研究机构所在国家等对文献分别统计（图2,图3,图4）。
Tab. 1
表1
表1近15年中亚地区水问题文献研究内容统计
Tab. 1Classification of research subjects of literatures on water issues in Central Asia during the last 15 years
| 研究分类 | 研究内容 |
|---|---|
| 水循环过程 | 水循环要素、水循环过程、冰雪覆盖、湖泊变迁、气候因子 |
| 水资源状况 | 水资源要素、河流水过程、水资源量、水生态、水污染 |
| 流域水环境 | 水文地理要素、流域社会经济因子、土地覆被与土地利用 |
| 跨界河流管理 | 地缘政治、国际关系、水资源战略、水资源管理 |
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显示原图|下载原图ZIP|生成PPT图2近15年中亚水问题英文文献统计结果
-->Fig. 2Statistics of English literatures on water issues in Central Asia during the last 15 years
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显示原图|下载原图ZIP|生成PPT图3近15年中亚水问题各国研究成果及研究方法
-->Fig. 3Research achievements in some countries and methodologies of water issues in Central Asia during the last 15 years
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显示原图|下载原图ZIP|生成PPT图4近15年中亚水问题中文文献统计结果
-->Fig. 4Statistics of Chinese literatures on water issues in Central Asia during the last 15 years
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中亚地区水问题一直受到相关国家的密切关注,特别是2007年后发表的英文文献数量急剧增加（图2a）,说明在2007年左右中亚水问题研究取得显著进展。在这些研究成果中,中亚地区水循环过程一直是重要的研究内容,2007年以后流域水环境受到国际上的广泛关注,自2010年起中亚地区跨界河流管理研究才有较大增长。从英文文献汇总统计结果可以看出（图2b）,中亚地区水问题中水循环过程、水资源状况、流域水环境和跨界河流管理4个领域均有一定成果积累,但相对来看有关水循环过程的研究成果最多,占全部英文文献的42%;其次为流域水环境研究,占全部英文文献的25%,水资源状况与跨界河流管理研究相对较少,分别占全部英文文献的19%和14%。
从2000以来中国、德国和美国等12个国家的****在国际期刊上发表的中亚地区水问题研究成果可以看出（图3a）,中、德两国发表的成果最多,分别占英文文献数量的25%和24%,两国研究成果合计占文献总数的一半;而中亚五国和俄罗斯等中亚地区国家的****发表的英文成果相对较少,合计为20%左右。在水问题的研究方法中,主要是利用统计资料与再生数据进行分析,占英文文献的40%,资料统计主要来源于政府各类统计报表和文献总结,再生数据主要来源于国际上公开的遥感同化数据;应用地面观测和地面实验数据开展研究占英文文献的30%;遥感数据的使用在中亚地区水问题研究中比较普遍,占英文文献的18%;应用水循环模型、流域水文模型开展的研究工作最少,仅占12%（图3b）。
与英文文献成果不同的是,国内有关中亚地区水问题研究成果增加的时间节点为2009年（图4a）,反映出国内对于中亚地区水问题研究起步较晚。但是中文文献中有关跨界河流管理的研究成果较多,自2000年以来,该部分研究成果数量占中文文献的63%（图4b）,其次为水循环过程和流域水环境的研究成果,几乎没有关于水资源状况的研究成果。研究方法以资料统计分析为主。
3 水循环过程
气候变化对水循环过程的影响一直是国际研究热点,气候变化会直接影响蒸散发、径流等水循环过程,从而引起区域水资源在空间和时间上总量和分布模式发生变化。中亚地区地处内陆干旱区,对气候变化响应十分敏感,近15年来中亚地区成为揭示全球气候变化对水循环影响的重要区域之一。有关水循环过程的研究主要集中在气温与降水指标变化特征分析,气温变化对高山冰川消退作用,以及水循环过程变化对河川径流和湖泊变化影响等方面。3.1 气温与降水变化
气温与降水是气候变化的标志性指标,二者对水循环过程有非线性的叠加作用,研究二者变化趋势有助于分析气候变化对水循环过程的影响。Chen等[5]利用美国气候中心降水空间数据分析了1930-2009年中亚地区降水变化趋势,结果表明在西风环流控制下,中亚地区降水持续增加,增加速率在1970年后显著上升;龙爱华等[6]通过咸海流域和中国新疆地区大量气候—水—生态统计资料,分析了近80年来中亚地区气候变化态势,认为中亚气候将由“暖干”向“暖湿”方向发展;Manning等[7]利用高分辨率区域气候模式REMO分析了中亚地区气候变化,预测了至21世纪末中亚地区气候变化趋势,其结果表明中亚地区气温在未来100年中将上升7 ℃。
总体来看,中亚地区近60年来气候变化趋势为气温升高、降水增加,与全球气候变化同步。但同时中亚地区具有其特殊性,IPCC第五次评估报告指出,到21世纪末在RCP 8.5情况下全球地表温度将上升2.6~4.8 ℃[8],根据Manning等[7]的计算结果,中亚地区气温上升幅度明显高于全球平均水平,气候变化对水循环过程的影响在中亚地区可能放大,因此研究中亚地区水文循环对气候变化的响应具有重要意义。
3.2 冰川消退
冰川是中亚地区重要的地表径流来源,冰川变化对中亚区域水循环影响巨大。气候变化导致冰川融化速度加快,退缩现象十分明显。Niederer等[9]的研究结果表明,在1963-2000年期间塔吉克斯坦境内天山山脉地区冰川减少了近28%,且退缩速度在20世纪80年代后明显加快;Li等[10]分析了近50年来中国乌鲁木齐一号冰川观测资料,发现1985年和1996年两年冰川退缩显著,且1996年冰川退缩幅度明显大于1985年;Krigel等[11]利用1970s、1990s后期、2000s中期MSS、TM和ETM+遥感数据以及2007年SPOT遥感影像,分析了天山地区冰川退缩状况,结果显示不到40年的时间内冰川减少了23%;Hagg等[12]应用WGI（World Glacier Inventory）和GLIMS（Global Land Ice Measurements from Space）模型估算中亚地区冰川退缩情况,结果表明到2050年,气温将上升2.2~3.1 °C,冰川将减少36%~45%。
上述研究表明,半个世纪以来中亚地区冰川持续减少,已有五分之一的冰川消失,且随着工业化进程加快冰川退缩呈加速态势,对于中亚地区水循环可持续发展极为不利。同时冰川作为中亚地区地表径流的主要来源,其退缩将导致该地区地表径流减少,从而影响社会和经济发展的水资源保障。
3.3 河流湖泊变化
受气候变化与冰川消融影响,水循环过程变化势必引起区域内河流湖泊的相应改变。河流湖泊是水循环的参与者,河川径流、湖泊水量受到水循环过程影响,同时河川径流、湖泊水量也会对水循环过程产生影响Deng等[13]应用长时间序列气候和水文观测资料分析了水循环过程对气候变化的响应,结果表明尽管在过去50年中降水增加,但冬季气温升高对水循环过程的影响更明显,冰雪覆盖退缩对径流减少的作用更显著;Aizen等[14]应用水循环模型分析了气候变化对天山地区水循环过程的影响,结果表明气温升高导致蒸散发增加,到2100年时蒸散发将增加83%~87%;气候变化对径流呈非线性影响,径流因此减少17%~13%;White等[15]应用水量平衡模型分析了气候变化条件下里海流域的河流水文变化,结果表明到2070-2099年虽然降水相对增加,但由于气温将升高5 °C,径流将因此减少10%~20%;Morris等[16]在吉尔吉斯斯坦地下水滞留的研究中也发现降水对地下水水量补给几乎没有作用。
河川径流的减少在一定程度上加剧了湖泊萎缩。程彦培等[17]利用3个时相MODIS数据,采用监督分类和人工解译方法获取中亚地区水体变化信息,结果表明咸水湖泊、淡水湖泊以及含水沟渠明显减少;Bai等[18]应用1975年、1990年、1999年多期遥感数据进行分析,结果表明1975-2007年湖泊面积减少了49.62%;李均力等[19]分析了2003-2009年间中亚地区24个典型湖泊的水位变化,认为冰川融水对高山封闭湖泊的减少有重要作用;Klein等[20]利用AVHRR和MODIS遥感数据分析了1986-2012年中亚地区内陆水体范围,也发现了湖泊萎缩的趋势。
气温和降水对水循环过程有叠加作用,而且呈非线性关系。尽管降水有所增加,但对水循环的贡献有限,难以弥补径流量的缺口。气温升高使蒸散发增加,导致河川径流减少,进而促使进入湖泊的水量减少,湖泊水面减小。
2012年“中亚生态系统和水文系统对气候变化和土地利用/覆被变化的响应”国际会议上,各国科学家第一次对中亚生态环境变化和人类适应问题进行了研讨,说明中亚地区气候变化对水循环过程的影响尚处于探索阶段,需进一步研究揭示水循环过程的变化趋势。同时,由于中亚地区下垫面因子空间异质性大,水循环时空变化非常复杂,高山冰雪带可靠观测数据匮乏,以及研究方法缺乏等因素,中亚地区水循环过程的深入研究也受到一定程度制约。
4 水资源状况
中亚地区地形地貌变化大,水资源时空分布不均,受气候变化与人类活动的影响,水资源供需矛盾不断加剧,中亚地区的淡水总量约1.09×1012 m3以上,但真正可利用的水资源约为2.66×1011 m3,其中地表水约为2.38×1011 m3,不重复的地下水约为2.80×1010 m3 [21-22]。近15年来对中亚地区水资源状况的研究主要集中在陆地水储量、河川径流量和农业灌溉量等变化分析方面。4.1 陆地水储量
陆地水储量是一个地区地表水与地下水总的水储量,可用重力卫星数据（Gravity Recovery and Climate Experiment, GRACE）和全球陆面数据同化系统（Global Land Data Assimilation System, GLDAS）反演计算。目前大多数****应用GRACE重力卫星数据进行区域水储量计算,揭示陆地储水量变化,评价地区水资源状况。Yang等[23]利用GRACE计算中亚地区2003年1月-2013年3月月尺度陆地等效水高,结果表明陆地水储量有明显年际和季节性波动,总体呈下降趋势,年均减少量为0.42±0.12 cm;孙倩等[24]利用2003年1月至2013年1月GRACE数据,辅以TRMM（Tropical Rainfall Measuring Mission）/CMAP（Climate Prediction Center's Merged Analysis of Precipitation）降水数据、NDVI（Normalized Difference Vegetation Index）植被指数和DEM（Digital Elevation Model）等多种数据,分析了中亚地区陆地水储量动态变化,结果表明中亚地区自东向西陆地水储量变化程度呈逐渐增加的趋势,陆地水储量总体呈下降趋势,但哈萨克斯坦东南部的巴尔喀什湖地区呈持续增长趋势。
中亚地区处干旱内陆区,虽然该地区水资源总量并不少,但真正可用的水资源量仅为水资源总量的24.4%,且应用GRACE卫星数据的研究成果表明该地区陆地水储量呈不断减少趋势,水资源短缺状况日益严峻。
4.2 径流量变化
中亚地区很多河流缺少水文站观测,应用水文模型计算河川径流是分析径流量变化的重要途径,因此中亚地区也是国际上开展缺少资料区水文模拟实验的重要区域。Cai等[25]以DTVGM模型为基础,结合多源空间数据（MS-spatial data）,构建了基于多源空间数据的DTVGM模型（MSDTVGM）,用于伊犁河流域径流计算与变化分析,减少了对常规观测的依赖;Radchenko等[26]应用了gap filling、MODAWEC（Monthly to Daily Weather Converter）方法解决了资料缺少的难题,并评价了这些方法对HBV-light模型计算精度的影响;Wang等[27]利用改进的SWAT模型模拟了1961-2007年天山地区冰川面积比率与径流的关系,量化了冰川退化在水文过程的作用;Siegfried等[28]通过气候变化、冰雪覆盖和降水径流耦合模型揭示了由气候变化导致的冰雪融化对径流季节性变化的直接影响;Ma等[29]在1961-1985年水文资料的基础上率定了SWAT模型,将GCMs（Global Circulation Models）数据进行降尺度,计算表明未来气候条件下楚河径流量将减少1.0%~26.6%。
地表径流是最易获取和利用的水资源之一,对地表径流的研究一直是水资源研究中的重点。中亚地区属于缺少水文资料地区,应用多源数据支持的流域水文模型来模拟分析径流变化是掌握该地区水资源状况的重要途径,可为该地区水资源管理提供可靠的数据来源。世界范围内水文模型众多,但被应用到中亚地区的相对较少,也反映出对该地区地表径流的研究尚在发展阶段。
4.3 灌溉用水
灌溉是中亚地区农业活动的重要手段。该地区约8.0×106 hm2的耕地面积依赖于地表水灌溉,中亚两大河流阿姆河和锡尔河灌溉用水量占总取水量的90%[21, 30],灌溉用水是中亚地区最主要的水资源利用方式。然而由于供水渠道蒸发量大和水利设施运行低效,水资源损耗巨大,如何提高农业灌溉用水效率是当前亟待解决的问题。Kitamura[31]分析了中亚地区水资源管理中面临的问题,发现用水协会（WUAs）在管理灌溉与维护供排水设施,提高农业用水效率方面发挥着重要作用;Iskandar等[32]分析了自上而下的集体农场式集中灌溉管理的局限性,认为新兴用水户小组（WUGs）是一种有效的管理措施,能够有效支撑WUAs的实施。
在WUAs农业灌溉用水管理基础上,建立可靠的农业用水效率评价方法十分重要。Awan等[33]利用相对蒸散发量（RET）、传输性能比（DPR）、径流系数（DR）、总消耗比（OCR）、田间利用比（FAR）和传送率（CR）作为指标,评价了WUAs灌溉管理的效益;Karimov等[34]应用经济核算方法分析农业节水潜力,通过上游冬季盈余水量在夏季重新分配供给下游,提高了灌溉效益;Platonov等[35]利用Landsat ETM+长时间序列数据生成灌溉作物的水分生产力图WPMs,并应用到灌溉管理中;Pereira等[36]应用ISAREG灌溉模型模拟改进后的灌溉制度,监测灌溉制度下作物根系区的渗流,提高灌溉效率20%;Conrad等[37]将基于对象的遥感分类数据与联合国粮食农业组织（FAO）提出的CropWat模型耦合,获取了棉花和冬小麦灌溉的作物分布和用水数据。
中亚地区农业种植以棉花、水稻等高耗水作物为主,两千年来农业灌溉一直是中亚地区水资源利用的主要方式[38]。提高灌溉水利用效率,改善灌溉技术和灌溉设施,减少蒸发等非生产性消耗水,建立农业灌溉的联合管理机制,加强水资源利用效益评价,对区域水资源可持续管理至关重要。在气象、水文、土地利用和水资源等丰富数据支持下,分析气候和水文系统的变化,以及它们与社会经济的相互作用和反馈机制,是未来中亚地区水资源利用研究的发展方向[2]。
5 流域水环境
气候变化和不合理的人类活动导致河川径流减少、河流水质恶化,环境退化严重影响到河流生态系统服务功能,危害流域水环境。近15年来,对于中亚地区流域水环境的研究主要集中在植被动态变化对气候变化的响应机制、流域环境要素、土壤盐渍化与土地退化、人口—资源—环境关系分析等4个方面。5.1 植被—气候响应机制
植被生长容易受到气候变化的影响,特别是中亚地区位于内陆干旱区,植被相对较少,对气候变化更加敏感。研究植被动态变化对气候变化的响应机制对揭示中亚环境的演变过程、预测环境发展趋势、维护流域水环境具有重要意义,因此植被变化常作为流域水环境的标志。索玉霞等[39]利用1982-2002年NDVI数据和气候研究组（CRU）降水与气温数据分析NDVI年际、季节变化特征与气候因子的相关关系,结果表明49%的地区年均NDVI与年降水量呈正相关,52%的地区NDVI与春季降水量正相关,34%的地区NDVI与夏季降水量正相关;Gessner等[40]利用1982-2006年的NDVI和网格化降水数据（GPCC Full Data Reanalysis）分析了植被生长对降水变化的敏感性,发现降水异常对中亚地区植被状况影响程度接近80%;张琪等[41]对中亚地区1982-2012年植被变化对气候变化的响应研究表明,NDVI的空间变化特征与降水的空间变化特征较为一致;Kariyeva等[42]应用1981-2008年遥感植被绿度数据分析了中亚地区植被物候与气候动态的关系,结果表明大多数物候响应变量与降水呈正相关,且气温升高使植被生长季提前,生长期延长。
气候变化对植被的影响具有复杂机制,降水与气温作为最直接的气候变化因子对植被动态作用十分明显。从目前研究结果可以看出降水增加有利于空间上植被覆盖度的提高,气温升高延长了年内植被覆盖时长,但对于更深层次植被—气候响应机制的研究仍然缺乏。
5.2 环境要素
环境要素是区域环境演变发展的基质,人类活动的过程中不可避免对环境要素进行改造、破坏,对环境要素的研究是了解水环境现状、预测水环境发展的基石。景观格局影响着流域内能量平衡和物质循环过程,植被根系吸水反映流域内植被生长状况,土壤水供给植被生长,是农业活动的必要条件。Luo等[43-44]应用Cellular Automata（CA）-Markov模型分析了哈萨克斯坦伊犁河三角洲景观格局时空动态,结果表明湖泊沼泽等水利景观受干扰明显,水利工程对三角洲景观结构变化作用最为深远;Li等[45]利用通用陆面模型CLM分析植被根系吸水过程,模拟植被对干旱环境的响应,获取了中亚荒漠生态系统的水汽通量数据;Devkota等[46]根据乌兹别克斯坦2008-2010年水稻和小麦生长季的实验数据,利用CSM-CERES-Wheat模型计算作物生长发育过程中土壤体积含水量变化;王景凯等[47]对2003-2010年中亚地表土壤水的研究结果表明,中亚地区植物生长季及春、夏季地表土壤水均以变干为主。
植被动态变化使流域景观格局、根系吸水、土壤水等环境要素随之变化,在一定程度上增加了水分的消耗。虽然有****已经对中亚地区流域环境要素展开研究,但目前对于该区域环境要素的研究仍显薄弱,尚不能为流域水环境管理提供充分的理论指导。
5.3 土壤盐渍化
农业是中亚五国的传统主导产业,这一特征一方面受地理环境、自然资源影响,另一方面中亚地区农业是前苏联时期社会主义计划经济的一个重要组成部分[48]。农业活动中大量施用农药化肥以及不合理的灌溉方式容易造成土壤盐渍化,严重威胁中亚地区的流域水环境。Devkota等[46]以水稻—小麦农业灌溉实验为基础,采用利润总额（GMs）估算和收益/成本率（BCR）评价农业灌溉与土壤盐渍化的收益与损害比例;Karimov等[49]用HYDRUS-1D模型研究浅层地下水位的影响,模拟结果表明由于水位上升和灌溉减少,地下水对蒸散发贡献增加,作物根系区盐分累积加剧;Chen等[50]从孔雀河采集了14个地表水和9个表层沉积物样品,检测结果表明含有绝大多数的有机氯农药;Crosa等[51]对阿姆河流域水质进行采样分析发现农业活动驱动和增加了次生盐渍化过程,导致阿姆河流域下游用水受到影响。
由于社会经济发展的需求,不合理的农业灌溉没有受到限制,加剧了土壤盐渍化程度,土地退化面积不断扩大,农作物产量减少,加重粮食危机;农药化肥施用危害到了水环境;劳动力、水资源和能源短缺提高了生产成本,对传统生产、生活方式提出了新的挑战。大范围的土壤盐渍化会对人类生存产生极大威胁,因此,合理利用土地、加强盐渍化土壤管理、改善水质的工作刻不容缓,对中亚地区土壤盐渍化形成的深层原因应受到重视。
5.4 人口—资源—环境关系分析
维持一个地区的可持续发展需要综合协调好人口—资源—环境之间的关系。人口数量增多会加大当地资源和环境的压力,厘清人口与资源、环境的关系有助于经济社会稳定发展。Schlüter等[52]分析了咸海萎缩与抽水灌溉的情况,认为应将环境流量纳入流域管理体系中,以提高湿地生态系统服务的供给能力,改善社会—生态系统的恢复力;Cretaux等[53]从千年尺度上分析咸海水位变化幅度和原因,提出了在人口不断增长的情况下咸海生态需水量和供水方案;Djanibekov等[54]以乌兹别克斯坦为例,研究了中亚地区人口饮食中水足迹变化,定量评价至2034年时食品消费国家的水足迹;Bekchanov等[55]利用均衡理论模型评价乌兹别克斯坦供水减少对整体经济的影响,结果表明当供水减少10%~20%,将减少灌溉24.1~37.4万hm2的土地,导致71.2~86.8万人口失业,国民收入损失3.6%~4.3%。
在人类文明伊始,绿洲农业就是建立在合理利用水资源的基础上,是一种自觉维护流域水环境的有效形式。中亚地区考古发掘的成果表明,自全新纪以来天山山麓地区人类就在不断改变生产生活方式,自觉维护流域生态环境可持续发展[56]。近年来由于气候变化,水循环过程和水资源分配发生变动,日益加剧的人类活动对水环境也造成深刻影响。处理好人口—资源—环境的和谐关系,构建有效水资源利用方式是维持中亚地区水环境的根本途径。
6 跨界河流管理
中亚地区跨界河流众多,水资源空间分布不均,供需矛盾十分突出。对有限资源的争夺导致跨界河流管理混乱,跨境水资源的合理分配利用、协调管理和可再生性维持,与复杂的地缘政治、区域经济等问题相互影响,越来越受到关注[57]。因此需要从自然资源、社会文化及地缘政治等多个维度来确立管理方法。多维度的跨界河流管理十分复杂,Stucki等[58]形象地将中亚水资源问题比喻成魔方,不仅中亚国家,美国、中国、欧盟等也参与其中,还有不同利益集团等使中亚地区跨界河流管理更加复杂。在水资源自然分布状况方面,位于上游的吉尔吉斯斯坦和塔吉克斯坦两国拥有中亚地区90%的水资源,而位于下游的乌兹别克斯坦、哈萨克斯坦和土库曼斯坦三国境内水资源径流补给较少,尤其是乌兹别克斯坦和土库曼斯坦几乎90%的水资源来自跨界河流[59]。然而由于国力悬殊导致中亚地区水资源供需矛盾突出,上游两国水资源利用量仅占11.4%,而下游乌兹别克斯坦、哈萨克斯坦和土库曼斯坦3个国家水资源使用量分别占52%、20%和10%[60-61]。水资源分布与利用的不均衡是该地区矛盾争端的重要原因,增加了引发国际冲突的可能性,为此中亚五国也努力寻找解决问题的出路。
随着苏联解体,中亚五国各自寻求经济发展,水资源利用的矛盾被不断激化,围绕跨界河流开发的争论愈演愈烈。为确保中亚地区水资源的使用与保护,改善咸海的生态环境,中亚五国分别于1992年和1993年成立了“水资源跨国协调委员会”和“拯救咸海国际基金会”,但由于这两个国际组织并不具有法律约束力,无法在法律层面上制约中亚各国的水资源分配与利用政策,因此对于中亚地区水资源管理作用有限。此外由于各方缺乏信任,上游国家与下游国家签订的一系列水资源区域性协定基本没有约束力,水资源滥用现象十分普遍[1]。
中亚地区混乱的跨境水资源管理引起了国际专家****的广泛关注,围绕该问题展开了一系列讨论。Abdullaev等[4]对比了乌兹别克斯坦水资源管理的历史与现状,结果表明传统的中央控制水资源管理方式正逐渐丧失;Abbink等[62]利用博弈论分析了中亚地区跨界河流管理中的合作与信任,结果表明中亚地区需要流域尺度的区域合作,但合作难以实现;廖成梅[59]关于中亚各国新建水电站建设的研究成果表明,各国在新建水电站问题上的不同立场,形成了对立的两派：上游国家追求能源独立,下游国家追求灌溉水利独立。各方缺乏解决问题的诚意,只从自己的立场考虑问题,并且限制流域内其他国家的利益,民族利己主义严重,水资源在中亚地区沦为政治工具和谈判筹码。
水资源是国家自然资源的组成部分,构建气候—水文—社会—政治相互协调的管理机制是确保跨界河流水安全的重要前提。Seidakhmetov等[63]认为水资源不仅是环境的组成部分,而且是调度机制的重要组成部分,应确保它们的法律基础、立法依据和技术支持;Sorg等[64]分析了气候—水文—社会—政治发展对锡尔河水量分配的影响,提出了应对水资源变化的适宜措施;Abdolvand等[3]认为中亚跨界河流管理与能源、政治紧密关联,该地区水量和能源储量丰富,但这些资源如何分配一直是各国争执的原因,导致了紧张的国际关系;Abdullaev等[65]研究成果表明中亚国家经济政策关注的依旧是提高资源开采而不是提高利用效率,工程水资源管理仍然在这些国家水资源部门占主导地位,现有制度难以从水—能源—农业—气候变化系统实现互利共赢。
自2000年以来,有关中亚地区水问题的国际会议频频召开,仅2009-2016年举行的国际会议就多达十余次。加强互利合作,有效保护和利用地区水资源是近15年来中亚水问题一成不变的议题。Karaye在2010年“生命之水”国际会议上指出,中亚地区存在的最大问题不是缺水,而是各方无法协商并达成共识。中亚五国由于产水与用水空间分布差异巨大,导致用水关系复杂,各国国家利益不同,过多强调他国对本国造成的损失,加大了水资源管理难度[57],混乱的管理导致水资源利用十分粗放,效率低下[66]。每一个国家都试图通过保障本国资源与能源的独立性,从而巩固其地缘政治地位。因此,中亚地区跨界河流管理超越了中亚地区边界,成为国际性问题,只有从全球地缘政治利益角度出发,才能全面有效地解决好该地区跨界河流管理问题。
7 结论
通过以上对文献的分析可以得出以下结论：（1）中亚地区水问题研究是地理学的研究热点之一。2007年以来中亚地区水问题受到国内外广泛关注,中国、德国和美国等国家的研究****开展了大量研究工作,取得一系列成果,研究工作主要集中在水循环过程对气候变化的响应和流域水环境两方面,中国在跨界河流管理的研究成果相对丰富;研究方法主要是利用统计资料与再生数据进行分析,遥感数据也有较为广泛的应用。
（2）中亚地区水循环过程深受气候变化影响,陆地水储量与河川径流减小趋势明显。中亚地区属于干旱气候区,地处欧亚大陆内陆中心,气候变化对水循环过程的影响十分显著,气温升高与降水增加是气候变化的基本特征,但气温升高的效应更大,导致冰川退缩,蒸散发增加,从而引起河川径流减少与湖泊萎缩,水资源状况将进一步恶化。
（3）气候变化与人类活动威胁着中亚地区流域水环境。气温上升延长了植被生长季,改变了植被景观格局,在一定程度上增加了水分的消耗;不合理的农业灌溉,加剧了土壤盐渍化,土地退化面积不断扩大;农药化肥施用加重了水环境污染;劳动力、水资源和能源短缺提高了生产成本,加大了流域水环境的压力。
（4）中亚地区跨界河流管理是当前国际社会面临的重大挑战。前苏联的解体,完全摧毁了原有水资源管理体系,加之近年来气候变化,各国之间用水问题日益恶化,引发了一系列生态问题,甚至危及到社会稳定与经济发展,中亚国家、美国、中国、欧盟等以及不同利益集团加入使中亚地区跨界河流管理成为复杂的地缘政治问题。
对近15年的研究成果分析表明,加强数据获取,增加地面观测,特别是高山冰雪带监测有助于深入分析中亚地区水循环过程机理;在丰富数据支持下,分析气候和水文系统变化,以及它们与社会经济的相互反馈机制,是未来中亚地区水问题研究的发展方向;协调好人口—资源—环境相互关系,构建高效水资源利用方式是维护中亚地区流域水环境的根本途径;从全球地缘政治角度,在气候—水文—社会—政治框架基础上开展研究才能全面解决好该地区跨界河流管理问题。
The authors have declared that no competing interests exist.
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| [1] | Large parts of Central Asia are characterized by a semiarid to arid climate. Therefore, areas close to shallow groundwater, rivers and lakes are characterized by unique water-dependent ecosystems and human societies which have developed over millennia in close interaction with the naturally limited water resources. In the early 21st century, global climate change, population growth, river damming, large-scale water abstractions and rising levels of pollution exert multiple pressures on the region’s water resources, aquatic and terrestrial ecosystems at historically high levels. Water scarcity threatens the livelihood of populations locally and in transboundary settings by a growing competition over a limited resource. This context is of particular importance since all major rivers of the region cross at least one international border. The complexity and character of water-related challenges in the region mean that management approaches need to be integrative, taking into account the natural resource basis, environmental limits and the socio-cultural and geopolitical dimension. This paper frames the thematic issue of Environmental Earth Sciences and provides a comprehensive overview about the current state of knowledge about water resources and their management in Central Asia. There is a focus on case studies looking at the Selenga–Baikal–Angara Basin, the Lake Aral Basin including the Syr Darya and Amu Darya river systems, the Tarim and the Illi River Basins. Aiming to be an up-to-date interdisciplinary scientific reference on the region’s water-related challenges, this thematic issue gives theoretical and practical insights into solutions and best practice examples of water management. |
| [2] | The MeOH extracts were separated by Sephadex LH-20 column chromatography; 22 and 19 fractions were obtained from A. macrophylla and A. stricta respectively . The fractions with different TLC profiles were tested for their antioxidant activity, evaluated as removal of the stable radical DPPH, total antioxidant capacity based upon the reduction of Cu ++ to Cu + and lipid peroxidation. Subsequently, the active fractions were purified using HPLC, and 4 active compounds could be isolated (Chlorogenic acid isomers, Rutin, Luteolin-7-O-glucoside, Apigenin-7-O-glucoside). |
| [3] | Central Asian water management has always been linked to energy and security politics. The region is abundant in water as well as in natural energy sources. However, distribution of these resources is a steady reason for quarrel within the region. In particular, the usage of mutually shared waterways creates tensions between different nation states. The five Central Asian republics Kazakhstan, Uzbekistan, Turkmenistan, Tajikistan and Kyrgyzstan seek energy independence and try to consolidate their position within this geopolitically important region. Despite their complex interdependencies, which affect all important social, economic, political and security relevant matters, Central Asian national states have initiated a disintegration process in the region. Economic crises after decades of mutual dependence make the region dependent on foreign investments. Within this complex setting, managing transboundary waters becomes a sensitive task that seems impossible to be resolved by the affected players themselves. Central Asian water management reaches beyond the borders of the region and has long become an international concern. This article analyzes how foreign geopolitical interests shape regional water management, and how capacity building measures can lead to sustainable management from within the region. |
| [4] | ABSTRACT This paper presents the analysis of historical transformation of water management in Central Asia with the specific focus on Uzbekistan. The time frame of the analysis is from the Middle Ages to contemporary times, with different political, social and economic settings in the framework of theory of transformative capacity of institutions. Empirical evidence suggests that the approach of the hydraulic mission has not changed dramatically over the years, but transformed into various forms of control on water management. In recent decades, integrated water resources management paradigms are gaining momentum, while the traditional, State-centric, hydraulic mission approach is losing its attractiveness in the arid Central Asian region. Nevertheless, the State-centric model of water management still persists in the region with clear signs that water management is still more under socio-political control. |
| [5] | This study analyzed the temporal precipitation variations in the arid Central Asia (ACA) and their regional differences during 1930-2009 using monthly gridded precipitation from the Climatic Research Unit (CRU). Our results showed that the annual precipitation in this westerly circulation dominated arid region is generally increasing during the past 80 years, with an apparent increasing trend (0.7 mm/10 a) in winter. The precipitation variations in ACA also differ regionally, which can be divided into five distinct subregions (I West Kazakhstan region, II East Kazakhstan region, III Central Asia Plains region, IV Kyrgyzstan region, and V Iran Plateau region). The annual precipitation falls fairly even on all seasons in the two northern subregions (regions I and II, approximately north of 45掳N), whereas the annual precipitation is falling mainly on winter and spring (accounting for up to 80% of the annual total precipitation) in the three southern subregions. The annual precipitation is increasing on all subregions except the southwestern ACA (subregion V) during the past 80 years. A significant increase in precipitation appeared in subregions I and III. The long-term trends in annual precipitation in all subregions are determined mainly by trends in winter precipitation. Additionally, the precipitation in ACA has significant interannual variations. The 2-3-year cycle is identified in all subregions, while the 5-6-year cycle is also found in the three southern subregions. Besides the inter-annual variations, there were 3-4 episodic precipitation variations in all subregions, with the latest episodic change that started in the midto late 1970s. The precipitations in most of the study regions are fast increasing since the late 1970s. Overall, the responses of ACA precipitation to global warming are complicated. The variations of westerly circulation are likely the major factors that influence the precipitation variations in the study region. |
| [6] | 中亚咸海流域地处全球气候变化的敏感中心，生态环境脆弱、水资源紧缺，过去百年来中亚咸海流域气候、人类活动、生态环境均经历了较为显著的变化，分析中亚咸海流域气候-水-生态-人类活动的关系，对自然与人文相近的新疆可持续发展具有重要的借鉴意义。以最新收集的资料为基础，对比研究近50 a来新疆及近80 a来中亚咸海流域的气温、降水和主要河流的径流变化情况，结合二者水资源开发利用的演变历程，分析气候变化与人类活动对研究区生态环境与持续发展的影响，最后借鉴中亚咸海流域气候变化、人类活动、生态环境的综合关系，讨论气候变化下新疆水资源开发利用的适应性对策。结果表明：近80 a来，新疆与中亚咸海流域气候呈现较为一致的变暖趋势，尤其是20世纪80年代以来，二者绝大部分地区气候呈现“暖干”向“暖湿”转型迹象，河川径流也有不同程度的增加，但由于人类活动规模与强度的迅速、持续增强，研究区生态环境呈现尚未得到有效遏制的恶化趋势。立足于有利的气候时期，强化水资源开发利用管理，提高水资源利用效率和效益，加快关键水源工程建设，完善水资源配置网络体系的建设，是未来一段时期内应对气候变化下新疆水资源开发利用的主要适应性对策。 . 中亚咸海流域地处全球气候变化的敏感中心，生态环境脆弱、水资源紧缺，过去百年来中亚咸海流域气候、人类活动、生态环境均经历了较为显著的变化，分析中亚咸海流域气候-水-生态-人类活动的关系，对自然与人文相近的新疆可持续发展具有重要的借鉴意义。以最新收集的资料为基础，对比研究近50 a来新疆及近80 a来中亚咸海流域的气温、降水和主要河流的径流变化情况，结合二者水资源开发利用的演变历程，分析气候变化与人类活动对研究区生态环境与持续发展的影响，最后借鉴中亚咸海流域气候变化、人类活动、生态环境的综合关系，讨论气候变化下新疆水资源开发利用的适应性对策。结果表明：近80 a来，新疆与中亚咸海流域气候呈现较为一致的变暖趋势，尤其是20世纪80年代以来，二者绝大部分地区气候呈现“暖干”向“暖湿”转型迹象，河川径流也有不同程度的增加，但由于人类活动规模与强度的迅速、持续增强，研究区生态环境呈现尚未得到有效遏制的恶化趋势。立足于有利的气候时期，强化水资源开发利用管理，提高水资源利用效率和效益，加快关键水源工程建设，完善水资源配置网络体系的建设，是未来一段时期内应对气候变化下新疆水资源开发利用的主要适应性对策。 |
| [7] | The high-resolution regional climate model (RCM) REMO has been implemented over the region of Central Asia, including western China. A model run forced by reanalysis data (1/2 degrees resolution), and two runs forced by a GCM (one run with 1/2 degrees and one run with 1/6 degrees resolution) have been realized. The model has been evaluated regarding its ability to simulate the mean climate of the period 1971-2000. It has been found that the spatial pattern of mean temperature and precipitation is simulated well by REMO. The REMO simulations are often closer to observational data than reanalysis data are, and show considerably higher spatial detail. The GCM-forced simulations extend to the year 2100 under the A1B scenario. The climate change signal of temperature is largest in winter in the northern part of the study area and over mountainous terrain. A warming up to 7 C is projected until the end of the 21st century. In summer, warming is strongest over the southern part of Central Asia. Changes in precipitation are spatially more heterogeneous. (C) 2013 Elsevier B.V. All rights reserved. |
| [8] | |
| [9] | <a name="Abs1"></a>The status and dynamics of glaciers are crucial for agriculture in semiarid parts of Central Asia, since river flow is characterized by major runoff in spring and summer, supplied by glacier- and snowmelt. Ideally, this coincides with the critical period of water demand for irrigation. The present study shows a clear trend in glacier retreat between 1963 and 2000 in the Sokoluk watershed, a catchment of the Northern Tien Shan mountain range in Kyrgyzstan. The overall area loss of 28% observed for the period 1963–2000, and a clear acceleration of wastage since the 1980s, correlate with the results of previous studies in other regions of the Tien Shan as well as the Alps. In particular, glaciers smaller than 0.5 km<sup>2</sup> have exhibited this phenomenon most starkly. While they registered a medium decrease of only 9.1% for 1963–1986, they lost 41.5% of their surface area between 1986 and 2000. Furthermore, a general increase in the minimum glacier elevation of 78 m has been observed over the last three decades. This corresponds to about one-third of the entire retreat of the minimum glacier elevation in the Northern Tien Shan since the Little Ice Age maximum. |
| [10] | Similar to most mountain glaciers in the world, Urumqi Glacier No. 1 (UG1), the best observed glacier in China with continued glaciological and climatological monitoring records of longer than 50 years has experienced an accelerated recession during the past several decades. The purpose of this study is to investigate the acceleration of recession. By taking UG1 as an example, we analyze the generic mechanisms of acceleration of shrinkage of continental mountain glaciers. The results indicate that the acceleration of mass loss of UG1 commenced first in 1985 and second in 1996 and that the latter was more vigorous. The air temperature rises during melting season, the ice temperature augment of the glacier and the albedo reduction on the glacier surface are considered responsible for the accelerated recession. In addition, the simulations of the accelerated shrinkage of UG1 are introduced in this article. |
| [11] | Glaciers are significant fresh water storages in Central Asian high mountains and are considered to substantially contribute to the summer runoff of Central Asian Rivers. We present a comprehensive study of the glacier area changes in the Naryn catchment located in the Tien Shan Mountains. The catchment with a size of 55,944 km(2) is a major tributary of the Syrdarya River which is heavily used for water supply and irrigation. We analysed the glacier retreat based on Landsat MSS, TM and ETM + imagery for the mid-1970s, late 1990s and mid-2000s and based on a SPOT scene for 2007. Our results show a decreasing glacierisation within the catchment, shrinking from 1210 +/- 30 km(2) (2.2% glacierisation) in the 1970s to 1019 +/- 25 km(2) (1.8% glacierisation) in the late 1990s and further down to 926 +/- 23 km(2) (1.7% glacierisation) in the mid-2000s, corresponding to an area loss of 23% in total. The analysis reveals spatially heterogeneous area loss within the catchment. This can be associated with different hypsometries, size distributions, aspects and presences of debris cover. Small glaciers (with an area <1 km(2)) suffered from a strong area loss within the 30-years investigation period.<br/>Trends in air temperature, precipitation and positive degree days (PDD) at climate stations suggest that the glacier retreat is likely to be driven by the increasing summer (April-September) temperature, rather than Changes in precipitation: In the period from 1960 to 2007, both summer air temperature and PDDs increased significantly at a rate of 0.19 degrees C/decade and 3.9 degrees C/decade respectively, whilst for precipitation no consistent trends were detected. However, rigorous attribution of changes is complicated by the variable glacier response times. In the two headwater sub-catchments of the Naryn basin, Small and Big Naryn, positive trends in spring and autumn discharge were detected and are likely to be associated with the enhanced snow and glacier melt driven by increasing temperatures in those seasons. However, no discharge trends in August the month with the largest expected glacier contribution - were detected. The strong, significantly positive trends in winter and early spring runoff are associated with strongly increasing winter temperatures and number of days with maximum daily temperature above the freezing point causing snow melt. Hence, increasing glacier area reduction can be explained by the prolongation of the melting season reducing accumulation rather than by increasing annual mean temperatures. Despite the high relative changes, the absolute increase in winter discharge is very small. (C) 2013 Elsevier B.V. All rights reserved. |
| [12] | A conceptual hydrological model was set up in the upper Panj catchment, the main tributary of Amu-Darya river. After a manual calibration procedure involving model runs with different restrictions, the model reproduced both daily hydrographs of Tanimas river at the Rukhk gauging station (NSE = 0.86) and the snow water equivalent of the Irkht station (R-2 = 0.85) in a very satisfactory way. Based on two glacier inventories from the mid-20th century (WGI, World Glacier Inventory) and from 2003 (GLIMS, Global Land Ice Measurements from Space), a simple parameterization scheme based on steady state conditions was applied to infer the ice volumes and glacier areas for these different time periods. Assuming temperature rises of 2.2 degrees C and 3.1 degrees C, which mark the extreme values of regional climate scenarios, the same method was used to extrapolate glacierization to the year 2050. The results show that these temperature rises will reduce the current glacier extent of 431 km(2) by 36% and 45%, respectively.<br/>To assess future changes in water availability, the hydrological model input was modified according to the regional climate scenarios and the resulting glacier changes. The use of an elevation distributed deglacierization pattern is a clear improvement over methods used previously, where the impact on runoff was tested by excluding either the lower half or the total glacier area. The runoff scenarios reveal only a slight reduction in annual runoff, because the glacier area decrease is almost balanced out by enhanced melt rates. However, there is an important seasonal shift of water resources from summer to spring, unfavorably affecting agriculture and irrigation in the lowlands. (C) 2013 Elsevier B.V. All rights reserved. |
| [13] | Climate change in complex mountain regions has an impact on the change of water resources, especially in arid areas. Here, we use long-term meteorological and hydrological station observation data to analyze the time series of climate indices and runoff to study the variability of climate in the Kaidu River Basin. The analysis results are as follows: 1) the variability rate of low temperature indices are of greater magnitude than high temperature indices; 2) overall, for the river basin, frost days and ice days all exhibited decreasing trends, and growing season lengths increased considerably; 3) during the past 50 years, overall precipitation has increased in the river basin, but there are some differences in some seasons, and precipitation from June to August accounts for approximately 66% of the annual precipitation; and 4) temperature lapse rate and precipitation of the mountain region are major factors influencing the change of runoff for the Kaidu River Basin, temperature lapse rates are the main factor influencing the run off change in the spring and fall, and precipitation in the mountain region is the major factor influencing the runoff change in the summer. Generally, climate change in complex mountain regions will be expected to seriously affect water resources in arid regions. |
| [14] | ABSTRACT This study simulates water resources in the Tien Shan alpine basins to forecast how global and regional climate changes would affect river runoff. The model employed annual mean values for the major characteristics of the water cycle: annual air temperature, precipitation, evapotranspiration and river runoff. The simulation was based on 304 hydro-meteorological stations, 23 precipitation sites, 328 high altitudinal points with glaciological measurements, 123 stream-gauges, and 54 evaporation sites, and it took into account topography. The findings were simulated over Tien Shan relief using a 1:500,000 scale 100 m grid resolution Digital Elevation Model. An applicable GIS-based distributed River Runoff Model was implemented in regional conditions and tested in the Tien Shan basins. The annual evapotranspiration exceeds the river runoff in the Tien Shan watersheds particularly up to 3700 m. Hypothetical climate-change scenarios in the Tien Shan predict that by 2100 river runoff will increase by 1.047 times with an increase in air temperature averaging 3 掳C and an increase in precipitation averaging 1.2 times the current levels. Change in precipitation, rather than temperature, is the main parameter determining river runoff in the Tien Shan. The maximum ratio for predicted river runoff could reach up to 2.2 and the minimum is predicted to be 0.55 times current levels. This possibly dramatic change in river runoff indicates on non-linear system response caused mainly by the non-linear response of evapotranspiration from air temperature and precipitation changes. In the frame of forecasted possible climate change scenarios the probability of river runoff growth amounts 83鈥87% and probability of this decline is 17鈥13% by 2100 in the Tien Shan River basins. |
| [15] | Central Asia is facing an unprecedented juxtaposition of regional climate- and water-related issues, emphasised by a changing climate. We investigate the potential impact of long-term climate change on the availability of water resources in the Amu Darya River, one of the two major rivers that feed the Aral Sea, and its effect on irrigation in the region. Using a water balance accounting model developed for the Amu Darya basin, we find that projected increases in summer temperatures of up to 5 °C by 2070–2099 under a high-emission scenario, combined with likely shifts in the seasonality of precipitation, would lead to an increase in crop water consumptive demand of between 10.6 and 16 % (or between 3.7 and 5.5 km3 y?1) relative to 1961–1990. By the end of the century, 34 to 49 % of the basin’s existing 3.4 million ha of irrigated land would go unirrigated in a 1:20 year drought. Runoff is also expected to decline by between 10 and 20 % on current levels, however contributions to river flows from unsustainable glacial retreat and snow-melt are likely to remain small. While the uncertainty surrounding the precipitation projections is high, the effect of increased temperatures on irrigation practices in the basin is more robust in the long-term |
| [16] | <a name="Abs1"></a>A groundwater residence time study of the deep fluvioglacial aquifer supplying Bishkek, capital of Kyrgyzstan, has found evidence of deep infiltration of recent recharge both in the main periurban wellfield and below the city. Commonly-employed hydrochemical markers detected urban influence in the city-centre to depths of 65–100 m, but gave no indication of the important role of induced river/canal bed leakage, either upgradient in the periurban wellfield or within the city. This was revealed by O and H stable isotope measurements, which showed that local rainfall/snowfall play little part in the aquifer water balance. More remarkably, the universal detection of CFCs and SF<sub>6</sub>, including in boreholes with 140–220 m deep upper screens, demonstrated that induced leakage of water just a few decades old had penetrated much deeper into the aquifer system than other hydrochemical markers indicated. A two-dimensional flow model set up to test whether such deep pumping-induced leakage could occur below the periurban wellfield confirmed its feasibility. The results imply vertical infiltration rates of 5–10 m/year and demonstrate that in this not-uncommon intergranular aquifer setting, deep boreholes with deep screen settings do not necessarily abstract old water. Hence, there are major implications for urban groundwater management and protection in such settings. |
| [17] | 水体动态监测是当今资源与环境变化研究的一个热点与重点.及时、 准确地获得水体变化信息是对湿地资源保护、利用和可持续发展的有力支持,而遥感技术的快速、周期性等特点为湿地变化监测提供了技术手段.本文的研究区是中 亚地区,结合该地区的光谱和时相特征,利用三个时相的MODIS数据,采用监督分类以及人工解译等方法获取了研究区水体分布以及变化信息,并从自然和人为 两方面原因对咸水湖泊、淡水湖泊以及含水沟渠的变化情况进行进一步分析评价. . 水体动态监测是当今资源与环境变化研究的一个热点与重点.及时、 准确地获得水体变化信息是对湿地资源保护、利用和可持续发展的有力支持,而遥感技术的快速、周期性等特点为湿地变化监测提供了技术手段.本文的研究区是中 亚地区,结合该地区的光谱和时相特征,利用三个时相的MODIS数据,采用监督分类以及人工解译等方法获取了研究区水体分布以及变化信息,并从自然和人为 两方面原因对咸水湖泊、淡水湖泊以及含水沟渠的变化情况进行进一步分析评价. |
| [18] | Inland lakes are major surface water resource in arid regions of Central Asia. The area changes in these lakes have been proved to be the results of regional climate changes and recent human activities. This study aimed at investigating the area variations of the nine major lakes in Central Asia over the last 30 years. Firstly, multi-temporal Landsat imagery in 1975, 1990, 1999, and 2007 were used to delineate lake extents automatically based on Normalized Difference Water Index (NDWI) threshold segmentation, then lake area variations were detailed in three decades and the mechanism of these changes was analyzed with meteorological data and hydrological data. The results indicated that the total surface areas of these nine lakes had decreased from 91,402.06 km(2) to 46,049.23 km(2) during 1975-2007, accounting for 49.62% of their original area of 1975. Tail-end lakes in flat areas had shrunk dramatically as they were induced by both climate changes and human impacts, while alpine lakes remained relatively stable due to the small precipitation variations. With different water usage of river outlets, the variations of open lakes were more flexible than those of other two types. According to comprehensive analyses, different types of inland lakes presented different trends of area changes under the background of global warming effects in Central Asia, which showed that the increased human activities had broken the balance of water cycles in this region. |
| [19] | 利用ICESat/GLAS 卫星测高数据产品获取2003-2009 年间中亚地区24 个典型湖泊的水位信息,分析该地区湖泊水位变化的时间过程和空间特征,并结合流域内气象观测数据和冰川、水坝分布图,分析不同类型湖泊的水位变化对气候变化与人类活动的响应。结果表明,湖泊水位变化与湖泊所在流域的年均降水量的变化呈显著的正相关;冰川融水对高山封闭湖泊的变化具有重要作用,其中在青藏高原北部、帕米尔高原和天山中部有大量冰川分布的流域,湖泊水位变化与湖泊补给系数呈正相关,水位主要表现为升高或稳定的状态;而在天山和阿尔泰山高地区无冰川补给的流域,水位随湖泊补给系数的增大而呈现负变化。水利枢纽或拦水坝为人类活动对湖泊的直接影响因子,其空间分布与近年来外流湖和平原尾闾湖的水位变化有关。拦水建坝的外流湖和尾闾湖的水位下降明显,而未建拦水坝或水利枢纽的外流湖水位相对稳定,进一步印证了近年来中亚水资源过度开发造成湖泊水位下降的事实。 . 利用ICESat/GLAS 卫星测高数据产品获取2003-2009 年间中亚地区24 个典型湖泊的水位信息,分析该地区湖泊水位变化的时间过程和空间特征,并结合流域内气象观测数据和冰川、水坝分布图,分析不同类型湖泊的水位变化对气候变化与人类活动的响应。结果表明,湖泊水位变化与湖泊所在流域的年均降水量的变化呈显著的正相关;冰川融水对高山封闭湖泊的变化具有重要作用,其中在青藏高原北部、帕米尔高原和天山中部有大量冰川分布的流域,湖泊水位变化与湖泊补给系数呈正相关,水位主要表现为升高或稳定的状态;而在天山和阿尔泰山高地区无冰川补给的流域,水位随湖泊补给系数的增大而呈现负变化。水利枢纽或拦水坝为人类活动对湖泊的直接影响因子,其空间分布与近年来外流湖和平原尾闾湖的水位变化有关。拦水建坝的外流湖和尾闾湖的水位下降明显,而未建拦水坝或水利枢纽的外流湖水位相对稳定,进一步印证了近年来中亚水资源过度开发造成湖泊水位下降的事实。 |
| [20] | In this study medium resolution remote sensing data of the AVHRR and MODIS sensors were used for derivation of inland water bodies extents over a period from 1986 till 2012 for the region of Central Asia. Daily near-infrared (NIR) spectra from the AVHRR sensor with 1.1 km spatial resolution and 8-day NIR composites from the MODIS sensor with 250 m spatial resolution for the months April, July and September were used as input data. The methodological approach uses temporal dynamic thresholds for individual data sets, which allows detection of water pixel independent from differing conditions or sensor differences. The individual results are summed up and combined to monthly composites of areal extent of water bodies. The presented water masks for the months April, July, and September were chosen to detect seasonal patterns as well as inter-annual dynamics and show diverse behaviour of static, decreasing, or dynamic water bodies in the study region. The size of the Southern Aral Sea, as the most popular example for an ecologic catastrophe, is decreasing significantly throughout all seasons (R-2 0.96 for April; 0.97 for July; 0.96 for September). Same is true for shallow natural lakes in the northern Kazakhstan, exemplary the Tengiz-Korgalzhyn lake system, which have been shrinking in the last two decades due to drier conditions (R-2 0.91 for July; 0.90 for September). On the contrary, water reservoirs show high seasonality and are very dynamic within one year in their areal extent with maximum before growing season and minimum after growing season. Furthermore, there are water bodies such as Alakol-Sasykol lake system and natural mountainous lakes which have been stable in their areal extent throughout the entire time period. Validation was performed based on several Landsat images with 30 m resolution and reveals an overall accuracy of 83% for AVHRR and 91% for MODIS monthly water masks. The results should assist for climatological and ecological studies, land and water management, and as input data for different modelling applications. (C) 2013 Elsevier B.V. All rights reserved. |
| [21] | <p>中亚五国地处欧亚大陆腹地，地理条件封闭，跨界河流众多，水资源形成区与消耗区严重不一致，水资源利用问题及矛盾十分突出，是全球跨界河流水资源开发利用与生态环境保护问题的典型代表，开展中亚水资源及其开发利用研究，对研究跨界河流及干旱区水资源可持续利用具有十分重要的借鉴意义。在介绍中亚五国及其主要河流概况，评价提出中亚五国地表、地下水资源量及其分布特点的基础上，阐述了中亚五国人口及城市化、经济发展与产业结构、耕地及其历史演变，分析了中亚五国的水资源开发利用现状，并对开发利用中存在的问题进行了综述总结。</p> . <p>中亚五国地处欧亚大陆腹地，地理条件封闭，跨界河流众多，水资源形成区与消耗区严重不一致，水资源利用问题及矛盾十分突出，是全球跨界河流水资源开发利用与生态环境保护问题的典型代表，开展中亚水资源及其开发利用研究，对研究跨界河流及干旱区水资源可持续利用具有十分重要的借鉴意义。在介绍中亚五国及其主要河流概况，评价提出中亚五国地表、地下水资源量及其分布特点的基础上，阐述了中亚五国人口及城市化、经济发展与产业结构、耕地及其历史演变，分析了中亚五国的水资源开发利用现状，并对开发利用中存在的问题进行了综述总结。</p> |
| [22] | 把新疆划分为伊犁河—额尔齐斯河外流区、准噶尔盆地—天山北坡经济区、塔里木盆地-塔里木河流域区和吐哈盆地诸小河流域区等4个水资源分区。系统分析估算了各分区的水资源总量、水资源可利用量以及水资源的利用现状、水资源的潜力及其承载能力,并参考已有研究结果进行了评述。新疆社会经济可利用的水资源量为598.96×108m3,新疆生态需水量为229.31×108m3;在建立节水型社会后,可以满足新疆社会经济、生态的需水。到2050年人均GDP81697.49元时,可承载的人口规模不低于3 250.8×104人。 . 把新疆划分为伊犁河—额尔齐斯河外流区、准噶尔盆地—天山北坡经济区、塔里木盆地-塔里木河流域区和吐哈盆地诸小河流域区等4个水资源分区。系统分析估算了各分区的水资源总量、水资源可利用量以及水资源的利用现状、水资源的潜力及其承载能力,并参考已有研究结果进行了评述。新疆社会经济可利用的水资源量为598.96×108m3,新疆生态需水量为229.31×108m3;在建立节水型社会后,可以满足新疆社会经济、生态的需水。到2050年人均GDP81697.49元时,可承载的人口规模不低于3 250.8×104人。 |
| [23] | |
| [24] | 利用2003年1月至2013年1月10 yr间的GRACE(Gravity Recovery And Climate Experiment)重力场恢复与气候实验重力卫星数据,辅以TRMM(Tropical Rainfall Measuring Mission)/CMAP(Climate Prediction Center’s Merged Analysis of Precipitation)降水量数、NDVI(Normalized Difference Vegetation Index)数据、DEM(Digital Elevation Model)数据等多种数据源及诸多GIS(Geographic Information System)手段,分析了121个月内研究区陆地水储量的动态变化情况.研究结果表明:⑴自东向西研究区陆地水储量变化程度由微弱逐步变化为非常剧烈;⑵巴尔喀什湖域外流区、鄂毕河流域以及部分叶尼塞河中下游地区的陆地水储量持续增长趋势显著;⑶锡尔河流域、阿姆河流域的交界处、幼发拉底-底格里斯河流域和里海西南海岸交界范围内,陆地水储量呈现了急剧降低的趋势;⑷降水量、蒸散发、地表植被的覆盖变化、地形因素等自然因素均对陆地水储量产生影响作用;⑸陆地水储量最大值出现的时间滞后于降水量最大值出现的时间. . 利用2003年1月至2013年1月10 yr间的GRACE(Gravity Recovery And Climate Experiment)重力场恢复与气候实验重力卫星数据,辅以TRMM(Tropical Rainfall Measuring Mission)/CMAP(Climate Prediction Center’s Merged Analysis of Precipitation)降水量数、NDVI(Normalized Difference Vegetation Index)数据、DEM(Digital Elevation Model)数据等多种数据源及诸多GIS(Geographic Information System)手段,分析了121个月内研究区陆地水储量的动态变化情况.研究结果表明:⑴自东向西研究区陆地水储量变化程度由微弱逐步变化为非常剧烈;⑵巴尔喀什湖域外流区、鄂毕河流域以及部分叶尼塞河中下游地区的陆地水储量持续增长趋势显著;⑶锡尔河流域、阿姆河流域的交界处、幼发拉底-底格里斯河流域和里海西南海岸交界范围内,陆地水储量呈现了急剧降低的趋势;⑷降水量、蒸散发、地表植被的覆盖变化、地形因素等自然因素均对陆地水储量产生影响作用;⑸陆地水储量最大值出现的时间滞后于降水量最大值出现的时间. |
| [25] | Hydrological simulation in ungauged regions is a popular topic in water resource and environmental research, and is also an important part of the international research initiative Predictions in Ungauged Basins (PUB). In this study, a multi-spatial data-based DTVGM (MS-DTVGM), combining multi-source spatial data (MS-spatial data) with the Distributed Time-Variant Gain Model (DTVGM), was built in order to reduce dependence on conventional observation, and was applied to the Ili River basin where traditional data sets are scarce. Because it utilizes MS-spatial data to measure precipitation, potential evapotranspiration, air temperature, vegetation parameters, and soil parameters, the model is driven purely by data from common platforms, thus overcoming the disadvantage of the large amounts of data typically required for distributed hydrological models. The inputs and simulation results were calibrated and validated using station or field observations. The results indicate that: 1) the MS-DTVGM is feasible in the Ili River basin; all model inputs can be acquired from multi-source spatial data and the key parameters are accurate; 2) the MS-DTVGM has good performance on a monthly time scale, and its simulation results can be used for a longer time-scale water resource analysis; and (3) daily runoff generation correlated strongly with snowmelt, the R-2 is about 0.69 indicating that the latter is an important contributor to water resources and suggesting that a snowmelt module is indispensable this area. The potential of distributed models for hydrological simulation in data-scarce regions using MS-spatial data was clearly demonstrated. |
| [26] | Abstract Glaciers and snowmelt supply the Naryn and Karadarya rivers, and about 70% of the water available for the irrigated agriculture in the Ferghana Valley. Nineteen smaller catchments contribute the remaining water mainly from annual precipitation. The latter will gain importance if glaciers retreat as predicted. Hydrological models can visualize such climate change impacts on water resources. However, poor data availability often hampers simulating the contributions of smaller catchments. We tested several data pre-processing methods (gap filling, MODAWEC (MOnthly to DAily WEather Converter), lapse rate) and their effect on the performance of the HBV (Hydrologiska Byr氓ns Vattenavdelning)-light model. Monte Carlo simulations were used to define parameter uncertainties and ensembles of behavioral model runs. Model performances were evaluated by constrained measures of goodness-of-fit criteria (cumulative bias, coefficient of determination, model efficiency coefficients (NSE) for high flow and log-transformed flow). The developed data pre-processing arrangement can utilize data of relatively poor quality (only monthly means or daily data with gaps) but still provide model results with NSE between 0.50 and 0.88. Some of these may not be accurate enough to directly guide water management applications. However, the pre-processing supports producing key information that may initiate rigging of monitoring facilities, and enable water management to respond to fundamentally changing water availability. |
| [27] | AbstractRunoff in the Amu Darya River (ADR) in Central Asia has been declining steadily since the 1950s. The reasons for this decline are ambiguous, requiring a complete analysis of glacio-hydrological processes across the entire data-scarce source region. In this study, grid database of precipitation from the Asian Precipitation Highly-Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE) and temperature from Princeton’s Global Meteorological Forcing Dataset (PGMFD) are used to force the distributed, glacier-enhanced SWAT model to simulate glacio-hydrological processes for 1951–2007 so as to determine long-term streamflow changes and the primary driving factors in the source region of ADR. The study suggests that the database was a suitable proxy for temperature and precipitation forcing in simulating glacio-hydrological in the data-scarce alpine catchment region. The estimated annual streamflow of 72.6 km3 in the upper ADR had a decreasing trend for the period from 19... |
| [28] | ABSTRACT Millions of people in the geopolitically important region of Central Asia depend on water from snow- and glacier-melt driven international rivers, most of all the Syr Darya and Amu Darya. The riparian countries of these rivers have experienced recurring water allocation conflicts ever since the Soviet Union collapsed. Will climate change exacerbate water stress and thus conflicts? We have developed a coupled climate, land-ice and rainfall-runoff model for the Syr Darya to quantify impacts and show that climatic changes are likely to have consequences on runoff seasonality due to earlier snow-melt. This will increase water stress in unregulated catchments because less water will be available for irrigation in the summer months. Threats from geohazards, above all glacier lake outbursts, are likely to increase as well. The area at highest risk is the densely populated, agriculturally productive, and politically unstable Fergana Valley. Targeted infrastructural developments will be required in the region. If the current mismanagement of water and energy resources can be replaced with more effective resource allocation mechanisms through the strengthening of transboundary institutions, Central Asia will be able to successfully address these future climate-related challenges. |
| [29] | Catchments dominated by meltwater runoff are sensitive to climate change as changes in pre-cipitation and temperature inevitably affect the characteristics of glaciermelt/snowmelt, hydrologic circle and water resources. This study simulated the impact of climate change on the runoff generation and streamflow of Chu River Basin (CRB), a glacierized basin in Central Asia using the enhanced Soil and Water Assessment Tool (SWAT). The model was calibrated and validated using the measured monthly streamflow data from three discharge gauge stations in CRB for the period 1961–1985 and was subsequently driven by downscaled future climate projections of five Global Circulation Models (GCMs) in Coupled Model Inter-comparison Project Phase 5 (CMIP5) under three radiative forcing scenarios (RCP2.6, RCP4.5 and RCP8.5). In this study, the period 1966–1995 was used as the baseline period, while 2016–2045 and 2066–2095 as the near-future and far-future period, respectively. As projected, the climate would become warmer and drier under all scenarios in the future, and the future climate would be characterized by larger seasonal and annual variations under higher RCP. A general decreasing trend was identified in the average annual runoff in glacier (–26.6% to –1.0%), snow (–21.4% to +1.1%) and streamflow (–27.7% to –6.6%) for most of the future scenario periods. The projected maximum streamflow in each of the two future scenarios occurred one month earlier than that in the baseline period because of the reduced streamflow in summer months. Results of this study are expected to arouse the serious concern about water resource availability in the headwater region of CRB under the continuously warming climate. Changes in simulated hydrologic outputs underscored the significance of lowering the uncertainties in temperature and precipitation projection. |
| [30] | |
| [31] | |
| [32] | This paper examines the recent emerging informal Water Users Groups (WUGs) on the Ferghana Valley for managing of the water at the former collective farm level and potential for strengthening of the weak Water Users Associations (WUAs) through replication of WUGs formation. Due to the collapse of the Soviet Union, Central Asian states have introduced reforms in different sectors including the water resources sectors. As a part of the water resources management reforms, Water Users Associations (WUAs) formation has implemented to manage water resources infrastructure and water distribution. WUGs have been emerging because WUAs have not been very efficient and effective due to their top-down implementation approach. In future, WUGs are very effective institutional mechanism of water resources management, and a useful support instrument to WUAs. |
| [33] | Irrigation water management in Central Asia is notorious for its inefficiency. We assessed the operational performance of the irrigation scheme in one Water Users Association (WUA), Shomakhulum, in Khorezm district, Uzbekistan, in 2007 to provide recommendations for strategic water management planning. Relative evapotranspiration (RET), delivery performance ratio (DPR), drainage ratio (DR), depleted fraction (DF), overall consumed ratio (OCR), field application ratio (FAR) and conveyance ratio (CR) were used as performance indicators. The components of the water balance were obtained through remote sensing techniques and hydrological field measurements. The surface energy balance algorithm for land (SEBAL) was applied to MODIS satellite data to derive actual and potential evapotranspiration. Inflows and outflows were quantified with field measurements in the irrigation and drainage network using discharge rating curves. Ponding experiments allowed determining canal seepage losses. Water balances at field level were established for application efficiency estimations. The indicator values were then compared to efficiency target values taken from the literature in order to assess the operational capabilities of the irrigation scheme. The general performance of the irrigation scheme is very poor. DPRs exceeding 1.0 indicate that more water is delivered to the system than is demanded. The seasonal DF of 0.4 is lower than the target value of 0.6. Losses during the field application averaged at 57%, which is 24% above target values. Seasonal DR, OCR, CR and RET are 0.55, 0.51, 0.76 and 0.82 against the target values of 0.1, 0.54, 0.84 and 0.75, respectively. We conclude that the distribution mechanism can be considerably improved. Besides improving water distribution (timing and equity) in the network, another recommended intervention would be to increase the DF, particularly by interventions at field level that raise the FAR, which in turn will improve DR and OCR. This can be achieved by introducing modern water management approaches such as laser leveling, double-sided irrigation, and control of inflow through flow-measuring devices installed at farm gates, and adequate water pricing. |
| [34] | The Syrdarya River basin in Central Asia exhibits symptoms of scarcity because of growing competition between hydropower upstream and environment, cities and agriculture downstream. Different approaches to water management, based on water savings in agriculture could relieve the stress of competition, yet keep alive a vibrant agriculture. The Fergana Valley, a highly productive area within the upstream of the Syrdarya River, was analyzed to determine the water savings potential of agriculture. This paper used a water accounting procedure to identify both the scope for savings and the strategies to realize those gains. Significant nonproductive depletion of water at 2681-4164 million m(3) (Mm(3)) was identified in the form of evaporation, flows to sinks and pollution. The water-saving potential is estimated at 2823 Mm(3) annually, which is about 10% of the total inflow into the area, through a range of practical approaches. This strategy would bring regional benefits by reallocation of surplus winter flow from the upstream for summer use in the downstream. (C) 2011 Elsevier B.V. All rights reserved. |
| [35] | The overarching goal of this paper was to espouse methods and protocols for water productivity mapping (WPM) using high spatial resolution Landsat remote sensing data. In a world where land and water for agriculture are becoming increasingly scarce, growing “more crop per drop” (increasing water productivity) becomes crucial for food security of future generations. The study used time-series Landsat ETM+ data to produce WPMs of irrigated crops, with emphasis on cotton in the Galaba study area in the Syrdarya river basin of Central Asia. The WPM methods and protocols using remote sensing data consisted of: (1) crop productivity (ton/ha) maps (CPMs) involvingcrop type classification, crop yield and biophysical modeling, and extrapolating yield models to larger areas using remotely sensed data; (2) crop water use (m3/ha) maps (WUMs) (or actual seasonal evapotranspiration or actual ET) developed through Simplified Surface Energy Balance (SSEB) model; and (3) water productivity (kg/m3) maps (WPMs) produced by dividing raster layers of CPMs by WUMs. The SSEB model calculated WUMs (actual ET) by multiplying the ET fractionby reference ET. The ETfraction was determined using Landsat thermal imagery by selecting the “hot” pixels (zero ET) and “cold” pixels (maximum ET). The grass reference ET was calculated by FAO Penman-Monteith method using meteorological data. The WPMs for the Galaba study area demonstrated a wide variations (0-0.54 kg/m3) in water productivity of cotton fields with overwhelming proportion (87%) of the area having WP less than 0.30 kg/m3, 11% of the area having WP in range of 0.30-0.36 kg/m3, and only 2% of the area with WP greater than 0.36 kg/m3. These results clearly imply that there are opportunities for significant WP increases in overwhelming proportion of the existing croplands. The areas of low WP are spatially pin-pointed and can be used as focus for WP improvements through better land and water management practices. |
| [36] | The Central Asian countries face high water scarcity due to aridity and desertification but excess water is often applied to the main irrigated crops. This over-irrigation contributes to aggravate water scarcity problems. Improved water saving irrigation is therefore required, mainly through appropriate irrigation scheduling. To provide for it, after being previously calibrated and validated for cotton in the Fergana region, the irrigation scheduling simulation model ISAREG was explored to simulate improved irrigation scheduling alternatives. Results show that using the present irrigation scheduling a large part of the applied water, averaging 20%, percolates out of the root zone. Several irrigation strategies were analyzed, including full irrigation and various levels of deficit irrigation. The analysis focused a three-year period when experiments for calibration and validation of the model were carried out, and a longer period of 33 years that provided for an analysis considering the probabilities of the demand for irrigation water. The first concerned a wet period while the second includes a variety of climatic demand conditions that provided for analyzing alternative schedules for average, high and very high climatic demand. Results have shown the importance of the groundwater contribution, mainly when deficit irrigation is applied. Analyzing several deficit irrigation strategies through the respective potential water saving, relative yield losses, water productivity and economic water productivity, it could be concluded that relative mild deficits may be adopted. Contrarily, the adoption of high water deficit that produce high water savings would lead to yield losses that may be economically not acceptable. |
| [37] | This study focuses on the generation of reliable data for improving land and water use in Central Asia. An object-based remote sensing classification is applied and combined with the CropWat model developed by the Food and Agriculture Organization (FAO) to determine crop distribution and water requirements for irrigation of cotton and winter-wheat in Fergana Valley, Uzbekistan. The crop classification is conducted on RapidEye and Landsat data acquired before the onset of the main summer irrigation phases in July using a random forest algorithm. The ClimWat database of FAO is utilized for calculating crop water requirements (CWR) and crop irrigation requirements (CIR).<br/>Classification reveals an overall accuracy of 86.2% and exceeds a producer's (user's) accuracy of 95% (89%) for both, cotton and wheat. In 2010, cotton and winter-wheat are planted on 66.7% of the agricultural area under investigation, whereas orchard areas amount to 15.5%. The CWR modelled for winter-wheat and cotton cultivation revealed 5443 m(3) ha(-1) and 9278 m(3) ha(-1), respectively. Subtracting effective precipitation leads to OR of 4133 m(3) ha(-1) and 8813 m(3) ha(-1). Comparisons of CWR and CIR for the area dominating crops with the total of water officially allocated for irrigation underline the pressure on the water resources in the entire Syr Darya catchment and suggest modifications of the cropping system towards more winter crops. The early season crop maps can be used for water saving as they enable modifications of water allocation plans within the different irrigation subsystems of the valley. The method for mapping spatially distributed CWR and CIR can be transferred to other irrigated areas in Central Asia and beyond. (C) 2013 Elsevier B.V. All rights reserved. |
| [38] | The Manas River valley is a typical inland river basin of an arid area in central Asia, and illustrates oasis evolution and economic development in this region. Based on the historical documents, monitoring data from field surveys, and remote sensing image data, this paper illustrates the oases evolution over the last 2,000 years and analyzes the rapid expansion of the Manas River oasis in the last 60 years. We also examine the relationship between oasis evolution and water resource utilization. We discuss the characteristics and effects of oasis expansion and the proposed adjustment measures for sustainable development of the Manas River valley. The principal objectives of this paper were to analyze the relationship between oasis expansion and water resource utilization over the last 60 years, and to solve the conflict between the continuous expansion of oases and a shortage of water resources to keep development of the Manas River valley sustainable. The results indicate that (1) oasis evolution in the Manas River valley over 2,000 years can be divided into three periods: a period dominated by animal husbandry, a period of semi-farming and semi-grazing, and a farming-dominated period. During the first two periods, the oasis area was limited, water conservancy facilities were poor and water utilization levels were low. In the third period, oasis expansion over the last 60 years shows a large-scale development. (2) The farming-dominated period can be subdivided into four phases according to the scale of water projects and the level of irrigation. Different oasis scales of the four phases show that artificial oasis evolution has a close connection with water resource utilization. (3) The evolution of oases in the Manas River valley raises some environmental problems although it plays an active role in promoting sustainability. Therefore, adjustment measures for the future development of oases could be proposed from the perspective of sustainable development, such as oasis scale control, forbidding reclamation, moderating exploitation of groundwater, and transforming industrial structures. |
| [39] | 本文利用1982年~2002年间AVHRR-NDVI数据和气候研究组（CRU）降水与气温数据，分析了中亚5国21年来NDVI年际与季节变化特征及其与气候因子的相关关系。结果表明：①在植被生长季，53%地区NDVI年变化率 <±0.0005NDVI/a（无变化），40%地区NDVI年变化率>0.0005 NDVI/a（增加），6%地区NDVI年变化率< -0.0005 NDVI/a（下降）；按照植被覆盖类型，除常绿林、高山草甸年均NDVI呈一定的上升趋势，变化率分别为0.0014 NDVI/a（p<sub>0.05</sub>=0.001），0.0009 NDVI/a（p<sub>0.05</sub>=0.001），落叶林、草原、作物、草原化荒漠NDVI没有显著变化（p<sub>0.05</sub>>0.05）；②年均NDVI与降水、温度相关性分析结果表明，49.00%的地区年均NDVI与年降水量呈正相关，52.33%的地区NDVI与春季降水量正相关，33.69%的地区NDVI与夏季降水量正相关，70.00%的地区年均NDVI与各季气温弱相关，仅17.78%的地区年均NDVI与年均气温正相关；6种植被类型NDVI与降水、气温相关关系为，常绿林、高山草甸年均NDVI与年均气温分别低度、显著正相关性，相关系数分别为0.432（p<sub>0.05</sub>=0.05）、0.557（p<sub>0.05</sub>=0.009）；草原、作物与年降水量分别显著、低度正相关，相关系数分别为0.511（p<sub>0.05</sub>=0.018）、0.476（p<sub>0.05</sub>=0.029）；落叶林NDVI与夏、冬季降水量低度正相关，相关系数分别为0.415（p<sub>0.05</sub>=0.061）、0.461（p<sub>0.05</sub>=0.035）；草原化荒漠NDVI与春季降水量正相关但不显著，相关系数为0.415（p<sub>0.05</sub>=0.061）。 . 本文利用1982年~2002年间AVHRR-NDVI数据和气候研究组（CRU）降水与气温数据，分析了中亚5国21年来NDVI年际与季节变化特征及其与气候因子的相关关系。结果表明：①在植被生长季，53%地区NDVI年变化率 <±0.0005NDVI/a（无变化），40%地区NDVI年变化率>0.0005 NDVI/a（增加），6%地区NDVI年变化率< -0.0005 NDVI/a（下降）；按照植被覆盖类型，除常绿林、高山草甸年均NDVI呈一定的上升趋势，变化率分别为0.0014 NDVI/a（p<sub>0.05</sub>=0.001），0.0009 NDVI/a（p<sub>0.05</sub>=0.001），落叶林、草原、作物、草原化荒漠NDVI没有显著变化（p<sub>0.05</sub>>0.05）；②年均NDVI与降水、温度相关性分析结果表明，49.00%的地区年均NDVI与年降水量呈正相关，52.33%的地区NDVI与春季降水量正相关，33.69%的地区NDVI与夏季降水量正相关，70.00%的地区年均NDVI与各季气温弱相关，仅17.78%的地区年均NDVI与年均气温正相关；6种植被类型NDVI与降水、气温相关关系为，常绿林、高山草甸年均NDVI与年均气温分别低度、显著正相关性，相关系数分别为0.432（p<sub>0.05</sub>=0.05）、0.557（p<sub>0.05</sub>=0.009）；草原、作物与年降水量分别显著、低度正相关，相关系数分别为0.511（p<sub>0.05</sub>=0.018）、0.476（p<sub>0.05</sub>=0.029）；落叶林NDVI与夏、冬季降水量低度正相关，相关系数分别为0.415（p<sub>0.05</sub>=0.061）、0.461（p<sub>0.05</sub>=0.035）；草原化荒漠NDVI与春季降水量正相关但不显著，相关系数为0.415（p<sub>0.05</sub>=0.061）。 |
| [40] | In Central Asia, water is a particularly scarce and valuable good. In many ecosystems of this region, the vegetation development during the growing season is dependent on water provided by rainfall. With climate change, alterations of the seasonal distribution of precipitation patterns and a higher frequency of extreme events are expected. Vegetation dynamics are likely to respond to these changes and thus ecosystem services will be affected. However, there is still a lack in understanding the response of vegetation to precipitation anomalies, especially for dryland regions such as Central Asia. This study aims to contribute to an improved understanding of vegetation sensitivity to precipitation anomalies and corresponding temporal reaction patterns at regional scale. The presented analyses are based on time-series of Normalized Difference Vegetation Index (NDVI) and gridded precipitation datasets (GPCC Full Data Reanalysis) for the years 1982-2006. Time-series correlation analyses show that vegetation development is sensitive to precipitation anomalies for nearly 80% of the Central Asian land surface. Results indicate a particularly strong sensitivity of vegetation in areas with 100-400 mm of annual rainfall. Temporal rainfall-NDVI response patterns show a temporal lag between precipitation anomalies and vegetation activity of 1-3 months. The reaction of vegetation was found to be strongest for precipitation anomalies integrated over periods of 2-4 months. The observed delayed response of vegetation to precipitation anomalies reveals potential for drought prediction in Central Asia. The spatial patterns of vegetation reactions are discussed with focus on the role of precipitation amount and seasonality, land use and land cover. (C) 2012 Elsevier B.V. All rights reserved. |
| [41] | 归一化植被指数(NDVI)能够反映植被生长状况,被广泛应用于区域乃至全球的植被变化研究中。该文利用1982–2012年GIMMS-NDVI数据,通过基于像元的线性趋势分析、偏相关分析,基于场域的经验正交分解(EOF)、奇异值分解(SVD),综合时间和空间两个维度上的信息,研究了近31年来中亚植被的变化及其变化中的区域差异,分析了植被对气候变化的响应关系。线性趋势分析发现,34%的中亚植被NDVI显著增长(p0.05),山区植被NDVI的增长速率可达到每年0.004。偏相关分析表明,63%的中亚植被受到降水的显著影响(p0.05,仅4%为负相关),而32%的植被受到气温的显著影响(p0.05,仅9%为正相关)。EOF分析发现,中亚植被NDVI的变化表现出较大的空间差异:山区及东北部的植被NDVI变化主要分为3个阶段,即先增长(1982–1994年)、后波动(1994–2002年)、然后继续增长(2002–2012年);而西北部平原区的植被NDVI变化主要表现为两个阶段,即先增长(1982–1994年)而后减少(1994–2012年)。SVD分析表明:1982–2012年间中亚植被受到降水和气温的共同影响,植被NDVI的空间变化特征与降水的空间变化特征较为一致,但西北部和山区的植被NDVI对气温的响应存在差异。 . 归一化植被指数(NDVI)能够反映植被生长状况,被广泛应用于区域乃至全球的植被变化研究中。该文利用1982–2012年GIMMS-NDVI数据,通过基于像元的线性趋势分析、偏相关分析,基于场域的经验正交分解(EOF)、奇异值分解(SVD),综合时间和空间两个维度上的信息,研究了近31年来中亚植被的变化及其变化中的区域差异,分析了植被对气候变化的响应关系。线性趋势分析发现,34%的中亚植被NDVI显著增长(p0.05),山区植被NDVI的增长速率可达到每年0.004。偏相关分析表明,63%的中亚植被受到降水的显著影响(p0.05,仅4%为负相关),而32%的植被受到气温的显著影响(p0.05,仅9%为正相关)。EOF分析发现,中亚植被NDVI的变化表现出较大的空间差异:山区及东北部的植被NDVI变化主要分为3个阶段,即先增长(1982–1994年)、后波动(1994–2002年)、然后继续增长(2002–2012年);而西北部平原区的植被NDVI变化主要表现为两个阶段,即先增长(1982–1994年)而后减少(1994–2012年)。SVD分析表明:1982–2012年间中亚植被受到降水和气温的共同影响,植被NDVI的空间变化特征与降水的空间变化特征较为一致,但西北部和山区的植被NDVI对气温的响应存在差异。 |
| [42] | Time-series of land surface phenology (LSP) data offer insights about vegetation growth patterns. They can be generated by exploiting the temporal and spectral reflectance properties of land surface components. Inter-annual and seasonal LSP data are important for understanding and predicting an ecosystem's response to variations caused by natural and anthropogenic drivers. This research examines spatio-temporal change patterns and interactions between terrestrial phenology and 28 years of climate dynamics in Central Asia. Long-term (1981-2008) LSP records such as timing of the start, peak and length of the growing season and vegetation productivity were derived from remotely sensed vegetation greenness data. The patterns were analyzed to identify and characterize the impact of climate drivers at regional scales. We explored the relationships between phenological and precipitation and temperature variables for three generalized land use types that were exposed to decade-long regional drought events and intensified land and water resource use: rainfed agriculture, irrigated agriculture, and non-agriculture. To determine whether and how LSP dynamics are associated with climate patterns, a series of simple linear regression analyses between these two variables was executed. The three land use classes showed unique phenological responses to climate variation across Central Asia. Most of the phenological response variables were shown to be positively correlated to precipitation and negatively correlated to temperature. The most substantial climate variable affecting phenological responses of all three land use classes was a spring temperature regime. These results indicate that future higher temperatures would cause earlier and longer growing seasons. |
| [43] | ABSTRACT The analysis of landscape pattern changes is of significant importance for understanding spatial ecological dynamics and maintaining sustainable development, especially in wetland ecosystems, which are experiencing indirect human disturbances in arid Central Asia. This study attempted to examine the temporal and spatial dynamics of landscape patterns and to simulate their trends in the Ili River delta of Kazakhstan through quantitative analysis and a cellular automata (CA)-Markov model. This study also sought to examine the effectiveness of using the CA-Markov model for investigating the dynamics of the wetland landscape pattern. The total wetland area, including the river, lake, marsh, and floodplain areas, and the area of sandy land have remained steady, while that of desert grassland has decreased slightly, and shrublands have increased slightly from approximately 1978 to 2007. However, the wetland and shrubland areas exhibited a trend of increasing by 18.6 and 10.3 %, respectively, from 1990 to 2007, while the desert grassland and sandy land areas presented the opposite trend, decreasing by 30.3 and 24.3 %, respectively. The landscape patterns predicted for the year 2020 using probabilistic transfer matrixes for 1990鈥2007 (Scenario A) and 1990鈥1998 (Scenario B), respectively, indicated that the predicted landscape for 2020 tends to improve based on Scenario A, but tends to degrade based on Scenario B. However, the overall Kappa coefficient of 0.754 for the 2020 predicted landscapes based on Scenarios A and B indicates that the differences in the predicted landscapes are not distinct. This research indicates that the applied CA-Markov model is effective for the simulation and prediction of spatial patterns in natural or less disturbed landscapes and is valuable for developing land management strategies and reasonably exploiting the wetland resources of the Ili River delta. |
| [44] | 在遥感和水文数据的支持下，根据伊犁河三角洲作为典型的中亚干旱区内陆河流域尾闾区域特点，确定了伊犁河三角洲的景观分类系统。通过采用景观结构梯度分析法、景观干扰度指数和景观Kappa指数等方法，系统地分析了近32 a（1975-2007）伊犁河三角洲景观结构的时空演变特征，并对景观结构的影响机制做了充分地探讨。结果表明：（1）沿着一定的地形梯度和水文梯度，伊犁河三角洲流域景观表现出特殊的纵向结构、横向结构的梯度特征和景观内部特征，与地表水直接关联的景观类型表现尤为明显，如湖泊、沼泽、漫滩。（2）在人为活动和自然环境的双重影响下，近32 a伊犁河三角洲景观结构的空间变化具有一定的周期性和不稳定性，主要体现为景观类型面积和空间位置的变化，其中以湿地景观类型的变化最为显著。（3）生态干扰对景观结构的影响因景观类型的不同存在显著的差异性和时空变异性，以湖泊和沼泽受干扰作用最为明显。高、中、低三种干扰强度区域的空间分布及面积变化同样具有一定的周期性和不稳定性。（4）水利工程建设和自然环境是影响伊犁河三角洲景观结构的主要驱动力。水利工程对伊犁河的拦蓄引起景观结构变化的作用最为深远，它通过改变三角洲上游的水文情势直接影响整个区域的景观结构。而自然环境因素中的地形和水文条件主要影响湿地景观类型的时空分布，气候因子则直接影响河川径流量。 . 在遥感和水文数据的支持下，根据伊犁河三角洲作为典型的中亚干旱区内陆河流域尾闾区域特点，确定了伊犁河三角洲的景观分类系统。通过采用景观结构梯度分析法、景观干扰度指数和景观Kappa指数等方法，系统地分析了近32 a（1975-2007）伊犁河三角洲景观结构的时空演变特征，并对景观结构的影响机制做了充分地探讨。结果表明：（1）沿着一定的地形梯度和水文梯度，伊犁河三角洲流域景观表现出特殊的纵向结构、横向结构的梯度特征和景观内部特征，与地表水直接关联的景观类型表现尤为明显，如湖泊、沼泽、漫滩。（2）在人为活动和自然环境的双重影响下，近32 a伊犁河三角洲景观结构的空间变化具有一定的周期性和不稳定性，主要体现为景观类型面积和空间位置的变化，其中以湿地景观类型的变化最为显著。（3）生态干扰对景观结构的影响因景观类型的不同存在显著的差异性和时空变异性，以湖泊和沼泽受干扰作用最为明显。高、中、低三种干扰强度区域的空间分布及面积变化同样具有一定的周期性和不稳定性。（4）水利工程建设和自然环境是影响伊犁河三角洲景观结构的主要驱动力。水利工程对伊犁河的拦蓄引起景观结构变化的作用最为深远，它通过改变三角洲上游的水文情势直接影响整个区域的景观结构。而自然环境因素中的地形和水文条件主要影响湿地景观类型的时空分布，气候因子则直接影响河川径流量。 |
| [45] | The ability of roots to take up water depends on both root distribution and root water uptake efficiency. The former can be experimentally measured, while the latter is extremely difficult to determine. Yet a correct representation of root water uptake process in land surface models (LSMs) is essential for a correct simulation of the response of vegetation to drought environment. This study evaluates the performance of the Common L and Model (CLM) to reproduce energy and water vapour fluxes measured with an eddy covariance system in a Central Asian desert ecosystem. The default CLM appears to be able to reproduce observed net radiation, soil subsurface temperature, and wet period latent (Q(ie)) and sensible heat (Q(h)) fluxes, but significantly underestimate Q(ie) and overestimate Qt during dry period. Underestimation of Qie is attributed to the inappropriate representation of root water uptake process in the CLM model. Modifying the original root water uptake function (RWUF) with a linear function of soil water potential to one with an exponential function significantly improves the performances for both Q(ie) and Q(h). The net radiation and ground heat flux simulations did not change noticeable with the new RWUF. It is concluded that an exponential RWUF is a valuable improvement of the CLM model and likely for other similar LSMs that use a linear RWUF for Central Asian desert ecosystems. (C) 2013 Elsevier B.V. All rights reserved. |
| [46] | Resource scarcity (labor, water, and energy) and high production costs are challenging the sustainability of conventional methods for rice and wheat establishment in Central Asia. Water saving irrigation and conservation agriculture (CA) practices (e.g., dry seeded rice, zero tillage wheat, residue retention) are potential alternative, resource-saving establishment methods. The Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model (CSM) can both be a valuable ex-ante and ex-post tool to evaluate the effects of water saving irrigation and resource saving CA-practices. The CSM-CERES-Rice and CSM-CERES-Wheat models of DSSAT were evaluated using experimental data from the 2008 to 2010 rice and wheat seasons as monitored in Urgench, the Khorezm region of Uzbekistan for growth, development of these crops, as well as soil mineral nitrogen (N) and volumetric soil moisture content in these cropping systems. Thereafter, the models were used to explore the long-term impact of water saving irrigation and CA-practices on grain yield, soil organic carbon (SOC) dynamics, N dynamics, and water balance in a rice heat rotation for 39 years starting from 1971. The simulation results showed that the simulated yield of water-seeded rice without residue retention and flood irrigation (WSRF-R0-FI) is likely to remain the highest and constant over 39 years. The simulated yield of dry seeded rice (DSR) with alternate wet and dry (AWD) irrigation and varying levels of residue retention was penalized for the initial years. However, the simulated rice yield increased after 13 years of CA-practices and continued to increase for the remaining years. Wheat did not experience a yield penalty for any of the treatments and simulated yield increased over time across all CA-practices based treatments. In the long-term, the effect of tillage methods and different residue levels for both rice and wheat were apparent in terms of grain yield and SOC build up. The results of the sensitivity analysis showed that WSR using AWD irrigation with puddling (WSRF-R0-AWD-Puddled) could give equivalent yield with that of WSRF-R0-FI and that irrigation water for rice could be reduced from 5435 mm to 2161 mm (or by 60%). Deep placement of urea in DSR (CT-DSR-AWD-DPUS) has the potential to increase yields of DSR by about 0.5 . Despite the huge water saving potential through the adoption of water saving AWD irrigation in DSR, a major challenge will be to prevent N losses. Substantial amounts of N losses through leaching, immobilization by residue mulch, combined with gaseous losses through volatilization and denitrification are the major causes for the lower simulated yield of rice for the AWD treatments. During the rice season, the implementation of water saving irrigation can improve water use efficiency by reducing percolation and seepage losses, which is an option in particular for WSRF-R0-FI. For both crops, the water use efficiency can be improved by lowering evaporation losses e.g. through residue retention on the soil surface. The creation of a sub-surface hard pan (puddling) and deep placement of urea super granules/pellet (DPUS) fertilizer could be the key for water saving and better yields of rice. Because CA-practices require almost three times less irrigation water than conventional method, and provide a long-term positive impact on grain yields of both crops, the CA-practices should be considered for double, no-till, rice heat cropping systems in the irrigated semi-arid drylands of Central Asia. |
| [47] | 综合利用3组AMSRE地表土壤水数据产品，运用集合分析的方法，生成中亚2003—2010年4—10月月均地表含水量数据，而后结合Climatic Research Unit（CRU）数据，分析了中亚8 a来地表土壤水变化特征及其对降水、气温等气候变化的响应。研究结果表明：① 中亚地区地表土壤水含量从西南向东、向北逐渐降低。② 中亚地区植物生长季及春、夏季地表土壤水均以变干为主，而秋季则以变湿为主。③ 集合分析数据时空分布与降水类似，与气温相反。在时间变化趋势上，中亚大部分地区降水减少、气温升高。夏季降水急剧减少而气温显著上升对中亚地区植物的生长是很不利的。④ 相关性分析结果表明，降水减少、气温升高是导致中亚植物生长季土壤干化的主导因素之一。 . 综合利用3组AMSRE地表土壤水数据产品，运用集合分析的方法，生成中亚2003—2010年4—10月月均地表含水量数据，而后结合Climatic Research Unit（CRU）数据，分析了中亚8 a来地表土壤水变化特征及其对降水、气温等气候变化的响应。研究结果表明：① 中亚地区地表土壤水含量从西南向东、向北逐渐降低。② 中亚地区植物生长季及春、夏季地表土壤水均以变干为主，而秋季则以变湿为主。③ 集合分析数据时空分布与降水类似，与气温相反。在时间变化趋势上，中亚大部分地区降水减少、气温升高。夏季降水急剧减少而气温显著上升对中亚地区植物的生长是很不利的。④ 相关性分析结果表明，降水减少、气温升高是导致中亚植物生长季土壤干化的主导因素之一。 |
| [48] | 中亚五国具有丰富的农业自然资源，我国具有技术和管理优势以及相对的资金优势。我国与中亚五国在农业领域有较好的互补性和互利性，具备很好的农业合作潜力，上海合作组织合作平台和地缘优势以及日益改善的中亚投资环境为我国农业“走出去”到中亚发展提供了很好的机遇，这种选择对提高我国粮食安全和资源性短缺农产品供给程度以及建立未来的海外出口基地具有深远的战略意义。 . 中亚五国具有丰富的农业自然资源，我国具有技术和管理优势以及相对的资金优势。我国与中亚五国在农业领域有较好的互补性和互利性，具备很好的农业合作潜力，上海合作组织合作平台和地缘优势以及日益改善的中亚投资环境为我国农业“走出去”到中亚发展提供了很好的机遇，这种选择对提高我国粮食安全和资源性短缺农产品供给程度以及建立未来的海外出口基地具有深远的战略意义。 |
| [49] | This paper analyzes the effect of the shallow water table on water use of the winter wheat (Triticum aestivum L.) that has replaced alfalfa (Medicago sativa) on the irrigated lands of the Fergana Valley, upstream of the Syrdarya River. in Central Asia. The effect of the shallow water table is investigated using HYDRUS-1D. Numerical simulations show that the contribution of the groundwater to evapotranspiration increases with a rising water table and decreases with increasing irrigation applications. Under irrigation conditions, an increase in the groundwater evapotranspiration is associated mainly with an increase in evaporation loss, causing a buildup of salinity in the crop root zone. Evaporation losses from fields planted with winter wheat after the harvest amount up to 45-47% of total evaporation thus affecting soil salinity and ecosystem health. Promoting the use of groundwater for irrigation in order to lower the groundwater table is suggested to achieve water savings from the change in the cropping pattern. Unlocking the potential of groundwater for irrigation in the Fergana Valley can also contribute toward managing soil salinity and improving the health and resilience of water. land and ecosystems of water, land and ecosystems (WLE). (C) 2013 Elsevier B.V. All rights reserved. |
| [50] | Fourteen surface water and nine surface sediment samples were collected from the Peacock River and analyzed for organochlorine pesticides (OCPs) by gas chromatograph-electron capture detector (GC-ECD). All the analyzed organochlorine pesticides, except o,p (')-DDT, were detected in sediments from the Peacock River; but in the water samples, only beta-HCH, HCB, p,p (')-DDD, and p,p (')-DDT were detected at some sites. The ranges for total OCPs in the water and sediments were from N.D. to 195 ng l (-aEuro parts per thousand 1) and from 1.36 to 24.60 ng g (-aEuro parts per thousand 1), respectively. The only existing HCH isomer in the water, beta-HCH, suggested that the contamination by HCHs could be attributed to erosion of the weathered agricultural soils containing HCHs compounds. Composition analyses showed that no technical HCH, technical DDT, technical chlordanes, endosulfans, and HCB had been recently used in this region. However, there was new input of gamma-HCH (lindane) into the Peacock River. The most probable source was water flowing from Bosten Lake and/or agricultural tailing water that was returned directly into the Peacock River. DDT compounds in the sediments may be derived mainly from DDT-treated aged and weathered agricultural soils, the degradation condition was aerobic and the main product was DDE. HCB in the sediment might be due to the input from Bosten Lake and the lake may act as an atmospheric deposition zone. There was no significant correlation between the concentrations of OCPs (including aHCH, aDDT, chlordanes, endosulfans, HCB and total OCPs) and the content of fine particles (< 63 mu m). The concentrations of OCPs were affected by salinity. |
| [51] | Although the use of the water resources in Uzbekistan is strongly limited by their quality, it has to be noted that there is a lack of information and data within the international scientific literature with regard to the water chemical characteristics of the Amu Darya River, one of the main water resources in Central Asia. To add to such knowledge, this paper examines the spatial and temporal variation of the water quality of the Amu Darya River in order to assess its degree of degradation and the main causal factors. The functional relationships of the pollutants with respect to the flow regime are investigated. Finally an "opportune temporal window" for water withdrawal for filling the reservoirs, in relation to human consumption, will be indicated. The high salinization levels of the waters are mainly due to the presence of sulphates and chlorine. At the up-stream site salinity, although presenting elevated concentrations, does not exceed palatability levels; after the 450 km point the opportune temporal window for water withdrawal with acceptable salinity values is reduced to the period from May to September. Two main driving forces govern the temporal variation of the salinity of the Amu Darya water: a low drainage density of the area which limits the salt loads induced by the natural runoff processes, and snow and glacier melting in the upper catchment area which promotes dilution of the dissolved salts during the high-flow period. During low-flow periods salinity is strongly influenced by the return of waters used for land washing and irrigation. |
| [52] | The wetlands of the Amudarya River delta in Uzbekistan provide valuable ecosystem services to the local human population which has suffered severely from the loss of the Aral Sea, desertification and the post-soviet socio-economic transition. The region is also particularly vulnerable to the impacts of climate change as a recent severe drought has shown. In this contribution, we assess the potential and implications of incorporating environmental flows into management of the Amudarya River for improving the provision of wetland ecosystem services and enhancing resilience of the social-ecological system to river runoff uncertainty. Our assessment is based on analyses of 1) the current vulnerability of deltaic wetlands to years of low water availability, 2) expected regional climate change and its impact on water flows to the wetlands, and 3) alternative water use options to enhance environmental flows under a changing climate. The results provide a ranking of these options with respect to their benefits for the provision of environmental flows and implications for agriculture. Their realization, however, poses challenges that cannot be tackled by technical interventions of redistribution and efficiency increase alone but call for institutional changes and moves towards multi-purpose water use. The diversification of impacts and livelihood options would allow enhancing the resilience of the social-ecological system to climate or socio-politically induced changes in water flow. (C) 2013 Elsevier B.V. All rights reserved. |
| [53] | The Aral Sea has shrunk drastically over the past 50 years, largely due to water abstraction from the Amu Darya and Syr Darya rivers for land irrigation. Over a longer timescale, Holocene palaeolimnological reconstruction of variability in water levels of the Aral Sea since 11,700 BP indicates a long history of alternating phases of regression and transgression, which have been attributed variously to climate, tectonic and anthropogenic forcing. The hydrological history of the Aral Sea has been investigated by application of a variety of scientific approaches, including archaeology, palaeolimnological palaeoclimate reconstruction, geophysics, sedimentology, and more recently, space science. Many issues concerning lake level variability over the Holocene and more recent timescales, and the processes that drive the changes, are still a matter for active debate. Our aim in this article is to review the current debates regarding key issues surrounding the causes and magnitude of Aral Sea level variability on a variety of timescales from months to thousands of years. Many researchers have shown that the main driving force of Aral Sea regressions and transgressions is climate change, while other authors have argued that anthropogenic forcing is the main cause of Aral Sea water level variations over the Holocene. Particular emphasis is made on contributions from satellite remote sensing data in order to improve our understanding of the influence of groundwater on the current hydrological water budget of the Aral Sea since 2005. Over this period of time, water balance computation has been performed and has shown that the underground water inflow to the Aral Sea is close to zero with an uncertainty of 3 km(3)/year. (C) 2013 Elsevier B.V. All rights reserved. |
| [54] | Assessing future water requirements for feeding the growing population of Central Asia can improve understanding of the projected water supply scenarios in the region. Future water requirements will be partially determined by the dietary habits of the populations, and are thus responsive to significant variation of income levels. Using Uzbekistan as an example, this study projects the water footprints of income driven changes on the population's diet in Central Asia. To reveal the influence of large income changes on dietary habits a Normalized Quadratic-Quadratic Expenditure System was calibrated and applied to data from 2009. The national water footprints of food consumption in Uzbekistah were projected until 2034 by applying the parameterized demand system to estimate the respective water footprint values. The results showed that for Uzbekistan the projected increase in the food consumption water footprint would be primarily linked to income growth rather than population growth. Due to the high water footprint of common food products, the composition of the population's diet, and responsiveness to income, economic growth is expected to put greater pressure on water resources in Uzbekistan unless proper measures are undertaken. (C) 2013 Elsevier B.V. All rights reserved. |
| [55] | Abstract Reduced river runoff and expected upstream infrastructural developments are both potential threats to irrigation water availability for the downstream countries in Central Asia. Although it has been recurrently mentioned that a reduction in water supply will hamper irrigation in the downstream countries, the magnitude of associated economic losses, economy-wide repercussions on employment rates, and degradation of irrigated lands has not been quantified as yet. A computable general equilibrium model is used to assess the economy-wide consequences of a reduced water supply in Uzbekistan—a country that encompasses more than half of the entire irrigated croplands in Central Asia. Modeling findings showed that a 10–20 % reduction in water supply, as expected in the near future, may reduce the areas to be irrigated by 241,000–374,000 hectares and may cause unemployment to a population of 712–868,000, resulting in a loss for the national income of 3.6–4.3 %. A series of technical, financial, and institutional measures, implementable at all levels starting from the farm to the basin scale, are discussed for reducing the expected water risks. The prospects of improving the basin-wide water management governance, increasing water and energy use efficiency, and establishing the necessary legal and institutional frameworks for enhancing the introduction of needed technological and socioeconomic change are argued as options for gaining more regional water security and equity. |
| [56] | In comparison to Southwest Asia and the Indian subcontinent, the relationship between Holocene river dynamics, climate change and floodwater farming in Central Asia is significantly under researched. To address this, a multi-disciplinary research project was begun in 2011 centred on the Talgar catchment, a south-bank tributary of the Ili River, southeast Kazakhstan. Building on archaeological excavations and surveys conducted over the past 20 years, we have undertaken investigations of Holocene human adaptations to changing hydromorphic regimes in the Tien Shan piedmont region, Central Asia. Fluvial geochronologies have been reconstructed over the last 20,000 years using Optically Stimulated Luminescence and 14 C dating, and are compared with human settlement histories from the Eneolithic to the medieval period. Phases of Late Pleistocene and Holocene river aggradation at c. 17,400–6420, 4130–2880 and 910–500cal. BC and between the mid-18th and early 20th centuries were coeval with cooler and wetter neoglacial episodes. Entrenchment and floodplain soil development (c. 2880–2490cal. BC and cal. AD 1300–1640) coincided with warmer and drier conditions. Prior to the modern period, floodwater farming in the Talgar River reached its height in the late Iron Age (400cal. BC – cal. AD 1) with more than 70 settlement sites and 700 burial mounds. This period of agricultural expansion corresponds to a phase of reduced flooding, river stability and glacier retreat in the Tien Shan Mountains. Late Iron age agriculturists appear to have been opportunistic by exploiting a phase of moderate flows within an alluvial fan environment, which contained a series of partially entrenched distributary channels that could be easily ‘engineered’ to facilitate floodwater farming. Holocene climate change was therefore not a proximate cause for the development and demise of this relatively short-lived (c. 200 years) period of Iron Age farming. River dynamics in the Tien Shan piedmont are, however, strongly coupled with regional hydroclimatic fluctuations, and they have likely acted locally as both ‘push’ and ‘pull’ factors for riparian agriculturists. |
| [57] | 本书是国际河流系列研究成果的重要组成部分，其主要内容包括：针对国际河流流域特点和跨境资源环境中的冲突问题，以跨境共享水资源的合理利用、公平分配与协调管理为核心，系统研究了国际河流共享水资源的水权、国际水法原则、水分配模式与指标体系、水利用冲突与求解方法、流域综合协调开发与管理理论等一系列前沿科学问题，并给出了解决跨境水及生态环境冲突、促进流域综合合理利用和协调管理的两个案例。本书适合于水文水资源、生态学、地理学、资源管理科学、环境科学、环境外交等领域的科技人员、管理人员和高校师生等应用。 本书是作者在近15年来完成的国家科技攻关项目、国家自然科学基金项目等研究基础上撰写而成，书中以世界广泛关注的跨境资源环境问题为研究对象，结合近几年国际上的研究进展，着重对国际河流流域的特点和合作开发中跨境资源环境问题，特别是跨境共享水资源的合理利用、公平分配与协调管理问题，进行了综合研究。在此基础上，系统地研究了国际河流共享水资源的水权、国际水法原则、水资源分配模式与指标体系、水冲突求解方法、流域综合开发与管理理论等一系列前沿科学问题。本书是我国第一本全面反映国际河流水资源开发与管理的理论专著，具有基础性、前瞻性与应用性，可供水资源开发与管理、环境科学、生态环境保护等部门的科研与管理人员，高等院校相关专业师生阅读、参考。 本书是国际河流系列研究成果的重要组成部分，其主要内容包括：针对国际河流流域特点和跨境资源环境中的冲突问题，以跨境共享水资源的合理利用、公平分配与协调管理为核心，系统研究了国际河流共享水资源的水权、国际水法原则、水分配模式与指标体系、水利用冲突与求解方法、流域综合协调开发与管理理论等一系列前沿科学问题，并给出了解决跨境水及生态环境冲突、促进流域综合合理利用和协调管理的两个案例。本书适合于水文水资源、生态学、地理学、资源管理科学、环境科学、环境外交等领域的科技人员、管理人员和高校师生等应用。 本书是作者在近15年来完成的国家科技攻关项目、国家自然科学基金项目等研究基础上撰写而成，书中以世界广泛关注的跨境资源环境问题为研究对象，结合近几年国际上的研究进展，着重对国际河流流域的特点和合作开发中跨境资源环境问题，特别是跨境共享水资源的合理利用、公平分配与协调管理问题，进行了综合研究。在此基础上，系统地研究了国际河流共享水资源的水权、国际水法原则、水资源分配模式与指标体系、水冲突求解方法、流域综合开发与管理理论等一系列前沿科学问题。本书是我国第一本全面反映国际河流水资源开发与管理的理论专著，具有基础性、前瞻性与应用性，可供水资源开发与管理、环境科学、生态环境保护等部门的科研与管理人员，高等院校相关专业师生阅读、参考。 |
| [58] | |
| [59] | 中亚各国近期围绕新建水电站的问题争执不断,基于各国在新建水电 站问题上的不同立场,形成了对立的两派.下游国家(哈萨克斯坦、乌兹别克斯坦、土库曼斯坦)和上游国家(塔吉克斯坦、吉尔吉斯斯坦)就水资源的合作问题无 法达成妥协.究其主要原因,包括:其一,中亚各国用水计划中存在根本的利益冲突.上游的国家追求能源独立,下游的国家追求灌溉水利的独立;其二,民族利己 主义.即所有各方都只从自己的立场考虑问题,并且限制流域内其他国家的利益;其三,水资源问题政治化.水资源问题不仅成为中亚国家内部的政治工具,而且也 会成为一些国家和组织利用的地缘政治工具. . 中亚各国近期围绕新建水电站的问题争执不断,基于各国在新建水电 站问题上的不同立场,形成了对立的两派.下游国家(哈萨克斯坦、乌兹别克斯坦、土库曼斯坦)和上游国家(塔吉克斯坦、吉尔吉斯斯坦)就水资源的合作问题无 法达成妥协.究其主要原因,包括:其一,中亚各国用水计划中存在根本的利益冲突.上游的国家追求能源独立,下游的国家追求灌溉水利的独立;其二,民族利己 主义.即所有各方都只从自己的立场考虑问题,并且限制流域内其他国家的利益;其三,水资源问题政治化.水资源问题不仅成为中亚国家内部的政治工具,而且也 会成为一些国家和组织利用的地缘政治工具. |
| [60] | Abstract In association with the Swedish Institute of International Affairs. |
| [61] | 中亚五国水资源分布不均衡，水资源利用效率不高。鉴于此，中亚水资源冲突不断升级。随着经济全球化及中亚各国经济的不断发展，中亚各国之间的水资源合作已成共识，但实际合作开发并不顺利。 . 中亚五国水资源分布不均衡，水资源利用效率不高。鉴于此，中亚水资源冲突不断升级。随着经济全球化及中亚各国经济的不断发展，中亚各国之间的水资源合作已成共识，但实际合作开发并不顺利。 |
| [62] | With the disintegration of the USSR a conflict arose between Kyrgyzstan , Uzbekistan and Kazakhstan over the transboundary Syr Darya river. Upstream Kyrgyzstan controls the Toktogul reservoir which generates hydropower demanded mainly in winter for heating. Downstream Uzbekistan and Kazakhstan need irrigation water in summer, primarily to grow an export crop (cotton). Regional agreements obliging Kyrgyzstan to higher summer discharges in exchange for fossil fuel transfers from downstream riparians in winter have been unsuccessful, due to lack of trust between the parties. Striving for self-sufficiency in irrigation water, Uzbekistan initiated new reservoir construction. This paper examines their economic impact. We report a laboratory experiment modelling the Syr Darya scenario as a multi-round, three-player trust game with non-binding contracts. Payoff schemes are estimated using real-life data. While basinwide efficiency maximisation requires regional cooperation, our results demonstrate that cooperation in the laboratory is hard to achieve. Uzbek reservoirs improve cooperation only weakly and their positive impact is limited to low-water years. |
| [63] | ABSTRACT Water resources are integral part of the natural resource potential of the country. Trans boundary water interests of the Republic of Kazakhstan are priority to ensure water security, where the key problem remains the continuing uncertainty of the status of trans Boundary Rivers. Urgency of the problem of trans Boundary Rivers’ water management is becoming increasingly important due to their revaluation. Kazakhstan, as a water-scarce state of the Central Asian region, needs to look for ways to improve its water balance, since the problem of water volume reducing, reflecting on economic indicators, on addressing protection of ecosystems, social guarantees of water supply, is connected to a greater extent with the inconsistency of border states’ interests, differences in the approaches and methods of trans boundary rivers’ water management. Thus, water resources are not only a component of the environment, but also the main component of the control mechanism, implementation of which will be available for long-term cross-border cooperation of states in order to converge the interests of the joint regulation of water use and consumption, development of their legal basis, its legislative consolidation, direct exposure corresponding to the level of technical and technological support. |
| [64] | This paper discusses how climatic-hydrological and socio-political developments will affect water allocation in the Syr Darya river basin and which adaptation measures will be needed to cope with changing water resources. In view of the geo-political complexity, climate-driven changes in water availability are of particular importance in this region. Water shortages during summer will become more frequent as precipitation is expected to further decrease and glacial meltwater releases will decrease in the long-term due to reduced glacier volume. Being the main valve to the entire Syr Darya river system, the Toktogul reservoir in Kyrgyzstan could take over, at least partly, the role of glaciers as seasonal water redistributors, thus allowing the generation of energy in winter -benefiting upstream countries - and irrigation for large-scale agriculture in summer-benefiting downstream countries. To date, however, there is no regional consensus on a balanced reservoir management, which currently favours irrigation according to past Soviet priorities. Moreover, the perception of water as a 'national concern' in Central Asia discourages efforts towards cooperation between states at the regional level. So far, climate change adaptation has focused on technical rather than institutional solutions. We suggest that policy-relevant adaptation measures should include consistent data collection and dissemination, cross-sectoral collaboration, promotion of national responsibility and initiative, and agreeing on a regional strategy. (C) 2013 Elsevier Ltd. All rights reserved. |
| [65] | Abstract Instead of re-orienting towards enhancing efficiency, the attention of political economies of the Central Asian States continues to be riveted on increasing resource extraction. Hydraulic mission (engineering water management) maintains its dominating status within water sector reforms of all countries. Forging mutually beneficial regimes for water–energy–agriculture–climate change systems as per the nexus concept requires robust governance and intersectorial coordination. It is historically evident that the Asian countries in question utilized a partial nexus system under the common Soviet centralized economic model. Within the nexus context, the current situation is outlined against the background of the boundary concept, security approach, and systems analyses as well as its holistic melding with the decade-long integrated water resources management efforts in Central Asia. The ability of existing institutional platforms, such as basin councils, to implement a nexus approach to local river catchments, regional watersheds or a national level is examined. |
| [66] | <p>中亚五国跨界河流众多，水资源开发利用问题十分复杂，大规模无序的水土资源开发利用引发的生态问题相当突出，回顾其开发利用中的冲突与合作，对找寻中亚水资源问题的解决之道具有重要的理论意义和实践价值。简要介绍了中亚五国之间主要跨界河流流域河流水系、径流量，阐述主要跨界河流域水资源开发利用，重点分析了各跨界河流取用水量与农业灌溉的演变关系以及中亚五国跨界河流开发利用的水资源危机与生态危机、冲突与合作。在深入揭示中亚五国跨界河流危机主要原因的基础上，对中亚五国跨界河流水资源纠纷和生态危机未来发展趋势进行了分析，探析了中亚五国跨界河流开发利用主要对策。</p> . <p>中亚五国跨界河流众多，水资源开发利用问题十分复杂，大规模无序的水土资源开发利用引发的生态问题相当突出，回顾其开发利用中的冲突与合作，对找寻中亚水资源问题的解决之道具有重要的理论意义和实践价值。简要介绍了中亚五国之间主要跨界河流流域河流水系、径流量，阐述主要跨界河流域水资源开发利用，重点分析了各跨界河流取用水量与农业灌溉的演变关系以及中亚五国跨界河流开发利用的水资源危机与生态危机、冲突与合作。在深入揭示中亚五国跨界河流危机主要原因的基础上，对中亚五国跨界河流水资源纠纷和生态危机未来发展趋势进行了分析，探析了中亚五国跨界河流开发利用主要对策。</p> |
