Hydrological and water cycle processes of inland river basins in the arid region of Northwest China

The increasing shortage in water resources is a key factor affecting sustainable socio-economic development in the arid region of Northwest China(ARNC). Water shortages also affect the stability of the region's oasis ecosystem. This paper summarizes the hydrological processes and water cycle of inland river basins in the ARNC, focusing on the following aspects: the spatial-temporal features of water resources(including air water vapor resources, runoff, and glacial meltwater) and their driving forces; the characteristics of streamflow composition in the inland river basins; the characteristics and main controlling factors of baseflow in the inland rivers; and anticipated future changes in hydrological processes and water resources. The results indicate that:(1) although the runoff in most inland rivers in the ARNC showed a significant increasing trend, both the glaciated area and glacial ice reserves have been reduced in the mountains;(2) snow melt and glacier melt are extremely important hydrological processes in the ARNC, especially in the Kunlun and Tianshan mountains;(3) baseflow in the inland rivers of the ARNC is the result of climate change and human activities, with the main driving factors being the reduction in forest area and the over-exploitation and utilization of groundwater in the river basins; and(4) the contradictions among water resources, ecology and economy will further increase in the future. The findings of this study might also help strengthen the ecological, economic and social sustainable development in the study region.

Mutual optimization of water utilization structure and industrial structure in arid inland river basins of Northwest China

Water is a key restricting factor of the economic development and eco-environmental protection in arid inland river basins of Northwest China. Although water supplies are short, the water utilization structure and the corresponding industrial structure are unbalanced. We constructed a System Dynamic Model for mutual optimization based on the mechanism of their interaction. This model is applied to the Heihe River Basin where the share of limited water resources among ecosystem, production and human living is optimized. Results show that, by mutual optimization, the water utilization structure and the industrial structures fit in with each other. And the relationships between the upper, middle and lower reaches of the Heihe River Basin can be harmonized. Mutual benefits of ecology, society and economy can be reached, and a sustainable ecology-production-living system can be obtained. This study gives a new insight and method for the sustainable utilization of water resources in arid inland river basins.

Ecological Land Suitability for Arid Region at River Basin Scale:Framework and Application Based on Minmum Cumulative Resistance(MCR) Model

As an important and typical arid inland region in China,Shiyang River Basin plays an important role in maintaining the sustainable development of eco-environment,whose ecological land suitability restricts the development of the local human activities.Therefore,Shiyang River Basin was selected as the case study,the minimum cumulative resistance(MCR)model and GIS technique were integrated to create land suitability evaluation map.We calculated the MCR value of ecological source and living source,and divided the whole basin into five partitions according to the difference between ecological source and living source,and analyzed the patterns and characteristics of the ecological land suitability evaluation(ELSE)regions,respectively.The results showed that:1)The suitable ecological land includes prohibited development region and restricted development region,which accounts for 15.45%and 23.35%of the total land area of the Shiyang River Basin,respectively.These two regions mainly distributed high altitude region in the southern Qilian Mountain and low altitude region where had high density of rivers.2)The protection of ecological land requires not only conserving existing ecological land but also focusing on ecological buffer belts around ecological sources and improving ecological land service ability.3)Ecological networks should be constructed through artificial planting trees around the boundary of oasis and ecological restoration region.Buffer greenbelts should also be established between optimized development region and ecological restoration region.

Impact of land use change on water resource allocation in the middle reaches of the Heihe River Basin in northwestern China

In recent decades, China has been experiencing rapid economic development, population growth and urbanization. These processes have stressed the shortages of water resources in China, especially in the arid re- gions of northwestern China. In order to sustain the expanding cropland, people increased groundwater exploitation in these regions. The purpose of this study was to quantitatively analyze the changes in land use and water resources, and their relationship in the middle reaches of the Heihe River Basin, a typical inland river basin in northwest China. The data of land use change were interpreted using aerial photographs （1965） and Landsat TM images （1986 and 2007）. The data of irrigation water volume in the irrigation districts were spatialized in the middle reaches of the Heihe River Basin. The spatial variation of the groundwater depth was interpolated using the geo- statistical method. The results showed that the cultivated cropland area along oasis fringe increased by 15.38% and 43.60% during the periods 1965-1986 and 1986-2007, respectively. Surface water amount for irrigation had almost doubled from 1956 to 2010. The decrease of grassland area mainly occurred at the alluvial fan in front of the Qilian Mountains, with 36.47% during 1965-1986 and 38.56% during 1986-2007, respectively. The groundwater depth in front of the mountain constantly increased from 1986 to 2007. We found that the overuse of surface water and overexploitation of groundwater had direct consequences on the natural environments. We suggests that the efficiency of surface water resources use among different irrigation distdcts needs to be improved, which will significantly ease the conflicts between increasing water demand for irrigation and a shortage of water resources in the middle reaches of the Heihe River Basin.

Water sources of plants and groundwater in typical ecosystems in the lower reaches of the Heihe River Basin

Stable oxygen and hydrogen isotopic compositions （δ18O and δD） of soil water and shallow groundwater of a riparian forest, an artificial shrub forest, and Gobi of the lower reaches of the Heihe River Basin are used to study the recharge water sources of those ecosystems. IsoSource software is used to determine the δ180 values for root water of Populous euphratica and Tamarix ramosissima in the riparian forest ecosystem, Haloxylon ammodendron in the artificial shrub forest, and Reaumuria soongorica in the Gobi, as well as for local soil water and groundwater, and precipitation in the upper reaches of the Heihe River Basin. Our results showed that soil water and shallow groundwater of the riparian forest and the artificial shrub forest were recharged by river water which originated from precipitation in the upper reaches, and strong evaporation occurred in the artificial shrub forest. Soil water of the Gobi was not affected by Heihe River water due to this area being far away from the river channel. The main water sources of Populous euphratica were from 40-60-cm soil water and groundwater, and of Tamarix ramosissima were from 40-80-cm soil water in the riparian forest ecosystem. In the artificial forest, Haloxylon ammodendron used 200-cm saturated-layer soil water and shallow groundwater. The Reaumuria soongorica mainly used soil water from the 175-200-cm depth in the Gobi. Therefore, soil water and groundwater are the main water sources which maintain survival and growth of the plants in the extremely arid regions of the lower reaches of the Heihe River Basin.

Assessing the evolution of oases in arid regions by reconstructing their historic spatio-temporal distribution： a case study of the Heihe River Basin, China

Oasis evolution, one of the most obvious surface processes in arid regions, affects various aspects of the regional environment, such as hydrological processes, ecological conditions, and microclimates. In this paper, the historical spatio-temporal evolution of the cultivated oases in the Heihe River Basin, the second largest inland watershed in the northwest of China, was assessed using multidisciplinary methods and data from multiple sources, including historical literature, ancient sites, maps and remotely sensed images. The findings show that cultivated oases were first developed on a large scale during the Han Dynasty （121 BC-220） and then gradually decreased in extent from the Six Dynasties period （220-581） to the Sui- Tang period （581-907）, reaching a minimum in the Song- Yuan period （960-1368）. An abrupt revival occurred during the Ming Dynasty （1368-1644） and continued through the Qing Dynasty （1644-1911）, and during the period of the Republic of China （1912-1949）, oasis development reached its greatest peak of the entire historical period. The oasis areas during seven major historical periods, i.e., Hart, Six Dynasties, Sui-Tang, Song-Yuan, Ming, Qing, and Republic of China, are estimated to have been 1703 kma, 1115 km2, 629 km2, 614 km2, 964 km2, 1205 km2, and 1917 km2, respectively. The spatial distribution generally exhibited a continuous sprawl process, with the center of the oases moving gradually from the downstream region to the middle and even upstream regions. The oases along the main river remained stable during most periods, whereas those close to the terminal reaches were subject to frequent variations and even abandonment. Socio-economic factors were the main forces driving the evolution of cultivated oases in the area; among them, political and societal stability, national defense, agricultural policy, population, and technological progress were the most important.

Effects of drip irrigation on components of water cycle in arid inland areas: A case study of Manas river basin in northwestern China

Compared to either drip irrigation or mulching with plastic film,the two methods together can reduce water requirements of crops grown in arid areas by more than 30%.Such a combination deployed on a large scale(1)reduced the loss of soil water by 31.8%compared to that from drip irrigation alone;(2)narrowed the range of annual evapotranspiration from 1582.4-1780.3 mm,which is average for the basin,to 222.2-294.8 mm;and(3)increased the overall humidity in the central plain of the basin.However,the surrounding regions in which drip irrigation is not combined with mulching are getting more arid;thus,as a result of the water-saving technology,both oases and the desertification of the river basin are increasing at the same time.The results of the study further the understanding of the effects of drip irrigation combined with mulching on water cycles in the basin of the Manas river and suggest ways to protect the ecology and the environment of the basin.

基于改进遥感生态指数的干旱内流区生态质量评价--以阴山北麓塔布河流域为例

干旱-半干旱地区生态环境脆弱,开展多要素、长时序生态质量动态变化研究,可为干旱-半干旱区生态建设与区域可持续发展提供科学依据。在遥感生态指数RSEI基础上,根据干旱-半干旱地区特点,耦合了绿度(NDVI)、湿度(WET)、热度(LST)、干度(SI)和盐度(SI-T)五个指标,提出适应干旱-半干旱区域生态质量评价的mRSEI模型,对1986—2022年间塔布河流域生态质量进行动态评价。利用Mann-Kendall突变检验、Theil-Sen(T-S)分析联合Mann-Kendall趋势分析法探究生态质量时空变化;引入欧洲中期天气预报中心发布的第五代再分析数据集(ERA5)的气象数据,在逐像元层面探讨了气候因素与mRSEI的相关关系。研究表明:(1)相较于RSEI而言,mRSEI能更好集成各生态分量包含的信息,且模型更加稳定可靠;(2)mRSEI受到的负面影响主要来自于盐度指标(SI-T),相关系数均值为-0.922,其影响力大于干度、热度指标,表明引入盐度指标对干旱-半干旱区生态质量评价具有重要意义;(3)研究时序内mRSEI介于0.179—0.423,生态质量总体呈下降趋势(Slope=-0.0014,P<0.05);(4)趋势分析结果表明,塔布河流域84.37%的区域生态质量未发生变化,另外15.63%中,生态质量退化面积占比远高于生态质量变好的区域,研究区生态质量总体呈退化趋势。(5)气候因素与mRSEI相关分析结果表明,降水与mRSEI呈正相关(r=0.411—0.807),年均气温与mRSEI呈负相关(r=-0.824—-0.398);时序相关分析结果表明,气温是研究区生态质量的主控因子。(6)人文因素虽然会对塔布河流域生态质量产生扰动,但并不起决定作用。基于改进的遥感生态指数mRSEI,能够科学监测干旱-半干旱区生态质量空间分布、准确把握生态质量变化趋势,可为干旱-半干旱地区生态保护提供理论支撑。

基于生态系统恢复力的干旱区植被生态需水阈值计算方法与应用

本文以石羊河流域中下游为研究区,采用考虑生态系统恢复力(latitude of ecosystem resilience,LER)的月尺度生态需水评估方法计算19822020年植被月适宜生态需水量、最小生态需水量以及相应的生态缺水量,并与土壤水分特征值法(characteristic value of soil water,CVSW)进行比较,分析不同类型植被生长期的水分盈亏关系。结果表明:LER法和CVSW法计算结果相近,但LER法具有更大的生态需水阈值区间;天然降水基本可以满足植被的基本生存,但无法满足正常生长需求;LER法的适宜需水条件下,各植被生长期总体处于缺水状态,缺水严重程度排序为灌木林>其他林地>疏林地>高覆盖度草地>中覆盖度草地>有林地,全部植被生长期总适宜生态需水量为3.7×10^(8)m^(3),亏缺水量为1.2×10^(8)m^(3),同一植被亏缺水量基本符合春秋多、夏季少的规律;最小需水条件下,只有其他林地存在生长期缺水情况,全部植被生长期总最小生态需水量为0.8×10^(8)m^(3);在缺乏土壤水分数据的干旱地区,LER法具有良好的适用性。研究结果可为石羊河流域水资源高效利用和干旱区生态系统的恢复与重建提供理论参考。

Relationship between Water and Vegetation in the Ejina Delta

Water is the foundation of an arid ecological system, as the quantity and quality of surface water and groundwater determine its structure and function. The study on the relationship between water and ecosystem is the basis of ecosystem protection. Taking the Ejina delta, an extremely arid area located downstream of the Heihe River in northwestern China, as an example, this article gives an overviewe of the study in three aspects: (1) the groundwater table and salinity dynamics and their driving factors, (2) the groundwater depth and salt threshold of natural vegetation ecosystem, and (3) the impact evaluation of ecological flow control on Ejina natural vegetation. The authors point out the importance of the research into the relation between water and ecosystem and its key difficulties and weakness, and put forward strategies for promoting the study processes.

基于格尔木河流域的SWAT模型水文特征情景模拟研究

以2008—2016年格尔木河流域实测径流量数据为基础,构建SWAT分布式水文模型,采用SUFI-2算法进行参数率定、验证及不确定性分析,并设置不同的气候情景(RCP2.6、RCP4.5和RCP6.0),预测流域2022—2050年的径流变化趋势,分析了研究区未来降水、气温的变化趋势并探究了这些气候要素对格尔木河流域径流的影响。结果表明:(1)SWAT模型在格尔木河流域径流过程的模拟中具有较好的适用性,率定期R2和ENS分别为0.84和0.73,验证期R2和ENS分别为0.74和0.70;(2)径流预测不确定性较小;(3)未来流域降水呈现增加趋势而气温降低;(4)未来时段流域径流增加显著,且降水是控制流域径流的主要因素。

黑河流域水资源合理开发利用研究

长期以来黑河流域水资源总量的不足 ,诱发了上下游之间、经济用水与生态和环境之间等一系列用水矛盾发生 .根据有关水文气象资料及前期研究成果对黑河流域水资源数量、特征、利用现状及供需平衡进行了分析研究 .结果表明 ,目前黑河流域水资源已呈现出严重不足 ,并且由此引起了流域内许多地方尤其是下游额济纳地区生态与环境的急剧恶化 .究其原因 ,固然与内陆地区气候干旱等先天不利条件有很大的关系 ,但最主要的原因还是人类对水资源的开发利用不当造成的 .因此 ,在区域社会经济的发展中 ,应充分考虑水资源的制约条件 ,从可持续发展的角度出发 。

黑河流域景观结构分析

在黑河流域土地利用分类的基础上 ,利用地理信息系统进行流域景观制图 ,划分出 6个景观区。利用景观结构分析软件 FRAGSTATS在流域尺度上计算了各景观区的多种景观结构指标。结果表明 :山区的景观结构特征突出表现为连通性强 ,拼块形状复杂。绿洲 -荒漠区的景观结构特征表现为 ,绿洲主要沿河流和渠道分布 ,是镶嵌在荒漠基质上的景观异质体。绿洲是干旱区景观结构最复杂 ,类型最丰富 ,景观多样性最高的地区 ,但不同景观区的绿洲其景观结构有显著的差异。荒漠和绿洲的过渡地带的过渡生态类型丰富 ,其共同的景观结构特征是拼块破碎、呈团聚状分布。在极端干旱的北部阿拉善高平原 ,裸露戈壁是景观模地 ,占据绝对优势 ,蔓延度极高 ,其它类型是面积相对很小的异质镶嵌体。文章最后指出 ,在使用

西北干旱内陆盆地地下水生态功能的探讨

以准噶尔盆地南缘地下水资源开发利用为例,分析地下水变化引起的区域地下水水位下降、泉流量衰减、水质恶化、植被退化、灌区土壤次生盐渍化与盐沼化、湖泊萎缩或干枯等生态环境效应,解析西北干旱内陆盆地地下水水位埋藏、潜水矿化度、包气带岩性与结构、土壤含盐量等地下水状态变量及其生态功能,提出地下水资源评价的内容与步骤:地质生态环境野外调查、地下水系统模型、地质生态环境系统模型及面向生态的地下水资源评价方法。最后就地下水系统参数确定和评价模型运转等问题展开讨论。

黑河流域水资源信息系统设计

建立黑河流域水资源信息系统的目标是为黑河流域水资源合理利用与经济社会和生态环境协调发展的研究提供基础数据和技术支撑 ,并辅助建立流域决策支持系统和水资源模型。本文介绍黑河流域水资源信息系统的设计和应用 ,共包括 2 7个图层的空间数据、40a气候和水文序列、以及部分NOAAAVHRR和TM遥感数据 ,是我国西北内陆河流域最完整的水资源信息系统之一 。

干旱内陆河流域平原区生态环境需水分析——以新疆自治区台兰河流域为例

从干旱区台兰河流域存在的环境问题出发,在确定流域平原区生态环境需水类型的基础上,构建了台兰河流域平原区生态环境需水定量模型,估算了流域平原区生态环境的规模。计算结果表明,台兰河平原区最大生态环境需水量为4.146×108m3,最小生态环境需水量为2.372×108m3,最适生态环境需水量为2.983×108m3,分别占台兰河平原区水资源总量(8.121×108m3)的51.05%,29.21%和36.73%。在不考虑河流输沙需水量的情况下,台兰河河流生态环境需水量平均为1.440×108m3。在考虑输沙需水量的情况下,河流生态环境需水量平均为2.604×108m3。明确了在确定流域生态环境需水量时,必须考虑研究区环境状况和生态保护目标,从而在不同区域和用水部门间进行调配,并针对流域不同的生态系统状况和对应生态系统类型确定了面向生态的水资源合理配置方案。

河西内陆河径流对气候变化的响应及其流域适应性水资源管理研究

为探讨河西地区内陆河径流对气候变化的响应,选取1955-2008年石羊河、黑河和疏勒河的河流流量资料进行计算和分析.结果表明:50多年来,石羊河年径流总体呈明显下降趋势,黑河呈略有增加趋势,疏勒河呈明显增加趋势,地域上呈现愈往西部的河流年径流量增加愈明显.三大河流进入1990年代后有下降趋势,进入21世纪均有明显增多趋势.三大河流径流对气候变化有不同响应,石羊河流域主要受季风气候影响,气候变暖,蒸发加剧,水分散失量大,是造成径流减少的主要原因;黑河和疏勒河流域主要受西风带环流影响,径流增多的重要原因是气候变暖降水明显增多.为减缓气候变化对流域水资源利用的不利影响,在分析三大内陆河流量对气候变化响应特征的基础上,提出了适应性水资源管理的建议.建议应提高水资源利用效率;改变生产方式,调整农业种植业结构与布局;加大祁连山自然保护区建设,搞好水资源可持续利用;积极开发祁连山丰富的空中云水资源、哺育祁连山冰川等流域适应性水资源管理对策,对流域进行综合治理与开发利用,这些措施和对策将为流域水资源开发提供科学依据.

基于层次分析法的干旱内陆河流域生态环境需水评价——以新疆台兰河流域为例

干旱内陆河流域生态环境需水综合评价是一个多层次,多目标的综合决策问题,同时是干旱区水资源合理配置与管理,生态环境保护与建设中最为关键的科学问题之一。根据台兰河流域的实际情况和环境问题,构建评价干旱内陆河流域生态环境需水状况的指标体系;该指标体系由3个层次38个评估因子组成;通过分级量化指标,用层次分析法对指标进行权重分析,提出了内陆河流域生态环境需水状况评判标准和具体的评价方法。结果显示,水资源因素对台兰河流域生态环境需水的影响最大,生态环境因素和经济社会因素次之,影响最小的是自然因素。水资源因素、生态环境因素、经济社会因素和自然因素之间相互关联,共同作用导致流域生态环境需水综合状况。评价结果与实际情况基本相符,证明层次分析方法在评价干旱内陆河流域生态环境需水状况中具有一定的应用价值。

西北干旱内陆河流域城镇化与水资源环境系统耦合机理

水资源是西北干旱内陆河流域经济社会可持续发展最基本的约束条件,城镇化是实现可持续发展的重要环节,水资源的高效合理利用和城镇化的健康有序发展均是影响该区域可持续发展的关键因素。剖析了城镇化与水资源环境系统之间存在的耦合机理以及不同发展阶段的耦合作用强度,阐述了内陆河流域水资源利用时空转移下的城镇发展演变机理。

干旱区内陆河流域城乡聚落体系空间结构及影响模式研究——以石羊河流域为例

本研究以石羊河流域为研究区,选取2000、2006、2010年三期遥感影像为数据源,采用成本加权距离和城乡聚落体系潜能指数对传统的场强模型进行改进,综合利用扩张强度指数、扩张速度指数等分析研究石羊河流域内部城乡聚落体系空间结构分异。在此基础上,基于GIS技术并结合道路等级和长度计算流域内城乡聚落体系间最短时间距离来分析城乡聚落体系空间联系与空间相互作用,据此分析石羊河流域城乡聚落体系空间结构变化及影响模式。