Simulation of hydrological processes of mountainous watersheds in inland river basins: taking the Heihe Mainstream River as an example

The hydrological processes of mountainous watersheds in inland river basins are complicated.It is absolutely significant to quantify mountainous runoff for social,economic and ecological purposes.This paper takes the mountainous watershed of the Heihe Mainstream River as a study area to simulate the hydrological processes of mountainous watersheds in inland river basins by using the soil and water assessment tool(SWAT)model.SWAT simulation results show that both the Nash–Sutcliffe efficiency and the determination coefficient values of the calibration period(January 1995 to December 2002)and validation period(January 2002 to December 2009)are higher than 0.90,and the percent bias is controlled within±5%,indicating that the simulation results are satisfactory.According to the SWAT performance,we discussed the yearly and monthly variation trends of the mountainous runoff and the runoff components.The results show that from 1996 to 2009,an indistinctive rising trend was observed for the yearly mountainous runoff,which is mainly recharged by lateral flow,and followed by shallow groundwater runoff and surface runoff.The monthly variation demonstrates that the mountainous runoff decreases slightly from May to July,contrary to other months.The mountainous runoff is mainly recharged by shallow groundwater runoff in January,February,and from October to December,by surface runoff in March and April,and by lateral flow from May to September.

Study of temperature and precipitation change in upstream mountain area of the Hexi inland river basin since 1960s

All rivers in the Hexi inland region of Gansu Province, China, originate from the northern slope of the Qilian Mountains. They are located in the southern portion of the region and respectively belong to the three large river systems from east to west, the Shiyang, Heihe and Shule river basins. These rivers are supplied by precipitation, snowmelt and ice-melt runoff from the Qilian Mountain area. Therefore, changes of precipitation and temperature in the upstream watersheds of these rivers have an important effect on changes of mountainous runoff and reasonable utilization of water resources in this region. For this reason, the Qilian Mountain area, upstream watersheds and runoff forming areas of these rivers are chosen as the study area. The change characteristics and variation trend of temperature and precipitation in this area under the backdrop of global warming axe analyzed based on observa- tional data of relational weather and hydrologic stations in the area. Results show that temperatures in the upriver mountain areas of these three large river basins have been increasing, although the increasing degree is differentially affected by global warming. The rising extent of annual and seasonal temperatures in the upstream mountain area of the Shule river basin located in the west- em Qilian Mountains, were all largest over the past 50 years. Precipitation in the upstream mountain areas of Hexi region＇ three river basins located respectively in the western, middle and eastern Qilian Mountains have been presenting an increasing trend to varying degrees as a whole for more than 50 years. This means that climate in the upstream mountain areas of Hexi region＇ three river basins are becoming increasingly warmer and moister over the past 50 years, which will be very good for the ecological en- vironment and agricultural production in the region.

A distributed runoff model for inland mountainous river basin of Northwest China

In order to predict the futuristic runoff under global warming, and to approach to the effects of vegetation on the ecological environment of the inland river mountainous watershed of Northwest China, the authors use the routine hydrometric data to create a distributed monthly model with some conceptual parameters, coupled with GIS and RS tools and data. The model takes sub-basin as the minimal confluent unit, divides the main soils of the basin into 3 layers, and identifies the vegetation types as forest and pasture. The data used in the model are precipitation, air temperature, runoff, soil weight water content, soil depth, soil bulk density, soil porosity, land cover, etc. The model holds that if the water amount is greater than the water content capacity, there will be surface runoff. The actual evaporation is proportional to the product of the potential evaporation and soil volume water content. The studied basin is Heihe mainstream mountainous basin, with a drainage area of 10,009 km 2 . The data used in this simulation are from Jan. 1980 to Dec. 1995, and the first 10 years' data are used to simulate, while the last 5 years' data are used to calibrate. For the simulation process, the Nash-Sutcliffe Equation, Balance Error and Explained Variance is 0.8681, 5.4008 and 0.8718 respectively, while for the calibration process, 0.8799, -0.5974 and 0.8800 respectively. The model results show that the futuristic runoff of Heihe river basin will increase a little. The snowmelt, glacier meltwater and the evaportranspiration will increase. The air temperature increment will make the permanent snow and glacier area diminish, and the snowline will rise. The vegetation, especially the forest in Heihe mountainous watershed, could lead to the evapotranspiration decrease of the watershed, adjust the runoff process, and increase the soil water content.

The changes in the annual distribution of mountain runoff during the period of 1965-2018 in Hexi Corridor,Northwest China

The annual distribution characteristics of river runoff in arid regions have significant implications for water resource stability and management.Based on the mountain runoff data from 1965 to 2018,this study examines the annual change characteristics of monthly runoff of the Shiyang River Basin,Heihe River Basin,and Shule River Basin in the Hexi Corridor,Northwest China.Many indexes are used and analyzed,including the coefficient of variance,the complete regulation coefficient,the concentration degree and concentration period,the magnitude of change,the skewness coefficient,and the kurtosis coefficient of the annual distribution curves.The results reveal the following:(1)The inhomogeneity of annual runoff distribution in the Taolai River and the rivers to the west of it,except the Shiyou River,show an increasing trend.Conversely,the inhomogeneity of the rivers to the east of the Taolai River generally show a downward trend,but the coefficient of variance value is still very high.(2)In the Shiyang River Basin,the annual distribution of the concentration period is characterized by a relatively discrete pattern.Conversely,the Heihe River Basin exhibits a relatively concentrated pattern,and the distribution pattern of the Shule River Basin is quite different.Notably,all concentration periods in the three basins have shifted backward after the 2000s.(3)The Shiyang River Basin exhibits disordered annual distribution curves of runoff in different years.In contrast,the Heihe River Basin presents a typical‘single-peak’pattern with a prominent right-skewed.The Shule River Basin has regular distribution curves,with a gradually significant‘double-peak’pattern from east to west.Overall,there has been a slight change in runoff in the Shiyang River Basin,while the Heihe River Basin and Shule River Basin have experienced significant increases in runoff.The annual distribution curves of runoff in the Liyuan River and the rivers to the east of it exhibit a gentle peak pattern,and the appearance probability of extreme runoff during the year is low.Conversely,the rivers to the west of the Liyuan River,excluding the Danghe River,display a sharp peak and thick tail pattern,indicating that the appearance probability of extreme runoff during the year is high.These findings have practical implications for the planning and management of water resources in the Hexi Corridor.Moreover,they provide a solid foundation for predicting future changes in regional water resources.

Snowline and Snow Cover Monitoring at High Spatial Resolution in a Mountainous River Basin Based on a Timelapse Camera at a Daily Scale

Snowline change and snow cover distribution patterns are still poorly understood in steep alpine basins of the Qilian Mountainous region because fast changes in snow cover cannot be observed by current sensing methods due to their short time scale. To address this issue of daily snowline and snow cover observations, a ground- based EOS 7D camera and four infrared digital hunting video cameras （LTL5210A） were installed around the Hulugou river basin （HRB） in the Qilian Mountains along northeastern margin of the Tibetan Plateau （38°15′54″N, 99°52′53″E） in September 2011. Pictures taken with the EOS 7D camera were georeferenced and the data from four LIL521oA cameras and snow depth sensors were used to assist snow cover estimation. The results showed that the time-lapse photography can be very useful and precise for monitoring snowline and snow cover in mountainous regions. The snowline and snow cover evolution at this basin can be precisely captured at daily scale. In HRB snow cover is mainly established after October, and the maximum snow cover appeared during February and March. The consistent rise of the snowline and decrease in snow cover appeared after middle part of March. This melt process is strongly associated with air temperature increase.

基于生态水文最优性理论的河西内陆河流域植被覆盖模拟

在生态恢复过程中,生态系统中植被所处状态对于生态平衡是否可持续至关重要,本研究以河西内陆河流域2000-2020年生长季气象和植被数据为基础,应用Eagleson生态水文最优性理论,模拟流域内生态水文平衡状态下的最优植被覆盖度Meq,植被覆盖度恢复阈值与当前现状植被覆盖度的差值即为植被恢复潜力。结果表明:1)模拟的多年平均最优植被覆盖度Meq与多年生长季平均实际植被覆盖度M的变化一致,但过渡更加平稳,呈现从东南向西北递减的趋势,流域内多年生长季平均实际植被覆盖度为0.163,模拟的多年平均最优植被覆盖度为0.166。2)流域内平均恢复潜力为0.003,植被覆盖度仍具有恢复潜力的面积占比为62.76%,分布在流域北部地区,3个流域内平均植被恢复潜力为石羊河流域>黑河流域>疏勒河流域。3)河西内陆河流域植被恢复潜力与区域干旱指数密切相关。森林的平均植被恢复潜力随着干旱等级增加呈减小的变化特征;而灌木植被覆盖度超过恢复潜力的程度随干旱指数增加呈先加剧后减轻的变化特征。

甘肃省河西内陆河实测出山径流量变化及其影响因素分析

甘肃省河西内陆河流域水资源极其短缺,流域内中西部和东部水系出山径流变化存在一定差异,研究出山径流量的变化情况及不同因素的贡献率,对保障区域水资源可持续开发利用具有重要意义。基于1956-2021年出山径流及主要产流区降水、气温资料,采用多种趋势和突变检验法、累积量斜率变化率法,结合径流补给特征,解析三大水系出山径流变化及其对降水、气温变化的响应情况,结果表明:(1)石羊河水系多年平均出山径流量13.60亿m^(3),历年呈不显著减少趋势,降水呈不显著增加趋势,气温显著升高使蒸发量增加,致使径流呈减少趋势;(2)黑河水系多年平均出山径流量由突变点2006年前的30.62亿m^(3)增加为突变点后的35.60亿m^(3),降水对径流变化的贡献率为16.7%,气温显著升高,对径流变化的影响增强;(3)疏勒河水系多年平均出山径流量由突变点1998年前的14.22亿m^(3)增加为突变点后的17.93亿m^(3),降水和气温对径流变化的影响相当,贡献率分别为30.4%、30.2%。河西内陆河三大水系径流补给特征、气候条件存在一定差异,致使径流对不同驱动因素的响应情况也不一致。

河西内陆河流域生态屏障建设综合评价与提升策略研究

生态屏障建设是推进人与自然和谐共生的中国式现代化的重要手段,内陆河流域生态屏障建设评价对于总结生态屏障建设成效与问题及落实中国式现代化建设战略任务具有重要意义。基于社会—生态耦合视角,在构建生态屏障建设评价指标体系基础上,运用综合指数法,对2015—2020年河西内陆河流域生态屏障建设状况进行了动态综合评价,并据此提出提升策略。结果表明:(1)河西内陆河流域生态屏障建设综合指数呈小幅上升态势,生态屏障建设处于发展提升阶段,流域生态安全多处于一般和较差状态;(2)流域生态屏障建设成效空间上整体呈现出自西往东逐渐下降的趋势,其中张掖市生态屏障建设成效明显,生态屏障建设综合指数稳步提升。基于上述研究,建议从社会—生态系统整体性出发,将生态屏障建设融入流域建设全过程,在生态产业、生态文化和生态社会等方面进行整体谋划和系统安排,统筹推进流域生态屏障建设转型提升。

祁连山国家公园(甘肃片区)土地利用时空演变及驱动因素分析——以黑河流域为例

黑河发源于祁连山北麓,黑河流域拥有丰富的生态资源,但受气候变化和人类活动的影响,生态风险明显增加。本文以黑河流域为例,分析2009—2018年祁连山国家公园(甘肃片区)土地利用时空演变,指出生态保护存在的主要问题,然后提出政策建议,以推动生态修复,遏制生态退化。总体来说,要强化监管,长效维持生态修复成果;加强管护能力,提升林区队伍专业化水平;提高居民生态意识,减少人类活动对环境的负面影响;开展综合治理,加速生态修复。

A model for simulating the response of runoff from the mountainous watersheds of inland river basins in the arid area of northwest China to climatic changes

A model for simulating the response of monthly runoff from the mountainous watersheds to climatic changes is developed. The model is based on the modifications to the HBV runoff model, and therefore represents the characteristics and runoff generation processes of inland river basins in the arid area of northwest China. Taking the mountainous watershed of an inland river, the Heihe River originating from the Qilian Mountains and running through the Hexi Corridor as an example, the monthly runoff changes under different climate scenarios are simulated. The simulation indicates that, during the years from 1994 to 2030, if the annual mean air temperature increases by 0.5℃ , and precipitation keeps unchanged, then the runoff of May and October will increase because of the increase of the snow melt runoff, but the runoff of July and August will decrease to some extent because of the increase of evaporation, and as a result, the annual runoff will decrease by 4 % . If the precipitation still keeps unchanged, and the air temperature increases by 1.0℃ , in addition to the increase of runoff of May and June, the runoff of July and August will decrease in a larger amount, making the annual runoff decrease by 7.11 % . If the air temperature keeps unchanged, the increase of annual precipitation by 10% will cause the increase of runoff by 5 .27% ; while the increase of precipitation by 20% will cause the increase of runoff by 12.35% . When the air temperature increases by 0.5℃ and the precipitation increases by 10% , the runoff will increase only by 1.62% .

Vulnerability and adaptation of an oasis social–ecological system affected by glacier change in an arid region of northwestern China

The Hexi Inland River Basin in an arid region of northwestern China was chosen as the study area for this research. The authors define the vulnerability of an oasis social-ecological system to glacier change; select 16 indicators from natural and socioeconomic systems according to exposure, sensitivity, and adaptive capacity; and construct a vulnerability-assessment indicator system aimed at an inland river basin in the arid region of Northwestern China. Vulnerability of the oasis socialecological system affected by glacier change in the study area is evaluated by Spatial Principal Component Analysis(SPCA) under the circumstance of glacier change. The key factors affecting the vulnerability are analyzed. The vulnerability of the oasis social-ecological system in the Hexi Inland River Basin affected by glacier change is of more than medium grade, accounting for about 48.0% of the total number of counties in the study area. In terms of the spatial pattern of the vulnerability, the oasis economic belt is the most vulnerable. With the rapid development of the area's society and economy, the exposure of the system to glacial changes is significantly increased; and an increase in glacial meltwater is not enough to overcome the impact of increased exposure, which is the main reason for the high vulnerability. Based on the result of the vulnerability analysis and combined with the present industrial structure in the Hexi Inland River Basin, near-,medium-, and long-term adaptation initiatives are put forward in the article.

WRF-Hydro模型参数在河西内陆河流域的敏感性分析

为研究WRF-Hydro模型参数在河西内陆河流域的敏感性,以西营河流域九条岭水文站以上区域为研究区,在离线模式下利用2015—2018年的全球预报系统(GFS)数据驱动WRF-Hydro模型。基于LH-OAT方法对WRF-Hydro模型的6个主要参数对不同评价指标和空间分辨率的汇流演算网格的敏感性进行了分析,定量计算了各参数的敏感性指标,划分了敏感度等级,并结合典型洪水分析了各参数对洪水过程线的具体影响。结果表明:河道曼宁糙率乘子(MANNFAC)为极敏感参数,入渗系数(REFKDT)、土壤饱和导水率(REFDK)、深层导水系数(slope)为敏感参数,地表糙率乘子(OVROUGHRTFAC)为一般敏感参数,地表持水深度乘子(RETDEPRTFAC)为不敏感参数;各参数的敏感性并不是一成不变的,参数敏感度会受到评价指标的影响,有一定程度的变化;随着汇流演算网格空间分辨率的变化,各参数全局敏感度也会有小幅变化,但参数的全局敏感度等级不发生改变;MANNFAC对峰现时间的调节效果最好,REFKDT和REFDK对洪量和洪峰流量的调节效果显著,slope可以很好地调节洪水过程线的形状。

祁连山讨赖河流域上游积雪时空分布及其变化研究

积雪是冰冻圈的重要组成部分,在水文循环和能量平衡中起着重要的作用。积雪时空分布及其变化分析是研究内陆河流域出山径流形成、分布及变异的前提。论文以祁连山讨赖河流域上游为研究区,采用降尺度方法获取高分辨率雪深数据,并基于Sen斜率法、敏感性分析和贡献率计算方法,分析2002—2018年间雪深时空变化,揭示积雪对地形及气候等因子的响应规律。结果表明:讨赖河流域上游雪深介于0~2.50 cm之间,变率介于-0.19~0.06 cm·a^(-1)之间,域内雪深减小面积占比68.30%。雪深随海拔的增大而增加,以海拔2 500 m为界发生增减变化,高海拔地区呈减小趋势;雪深随坡度增加则呈先增后减的趋势;各坡向雪深均呈减小态势,西北坡尤为显著。从敏感性均值来看,气温和辐射对雪深具负向抑减效应,降水则具正向促增效应。高海拔区域降水对积雪变化的贡献率相对较大;低海拔河谷地带气温对积雪变化的贡献更为显著。本研究为内陆河流域上游积雪动态研究提供了范例,对出山径流模拟、预测以及流域水资源管理具有一定参考价值。

气候变化对河西内陆干旱区出山径流的影响

根据祁连山区与河西走廊平原区有关水文气象台站的降水、气温和径流观测资料 ,分析了该区域近 5 0a来气候变化的特征及其与全球气候变暖的关系、出山径流对气侯变化的响应以及未来的变化趋势 .结果表明 ,河西内陆干旱区的山区和走廊平原区近几十年来气温变化总的呈上升趋势 ,与全球增温存在着某种程度的一致性 .但山区气温的变化幅度一般大于走廊平原区 ,其中祁连山中段温度升幅为最大 .全球增温对河西内陆干旱区气候与出山径流的影响有着明显的地域性差异 ,受此影响影响 ,河西祁连山东部地区出山径流呈明显的下降趋势 ,中部地区出山径流的增加趋势不是十分明显 ;西部出山径流在山区降水量与气温同时上升的情况下 ,呈明显的上升趋势 .

祁连山与河西内陆河流域绿洲的大气水循环特征研究

祁连山和河西走廊地区为西风带、青藏高原季风、东南季风三个大气环流系统的耦合区,其内陆河流域的大气水循环特征受大气环流影响比较显著.根据已公布文献提供的资料,分析了祁连山区年平均降水与海拔和大气环流影响系统之间的关系,研究了祁连山发育的内陆河流域的绿洲水平空间尺度的分布特征,探讨了海拔和绿洲植被密集度对绿洲地表蒸发力的影响,揭示了绿洲单位面积耗水量与绿洲灌溉率之间的关系.最后,讨论了内陆河流域绿洲的特点以及开发和保护的思路.

祁连山中段北坡最大降水高度带观测与研究

2006年6月至2008年9月,在祁连山中段北坡黑河流域上游进行了降水空间变化的统观测.结果表明：在黑河上游流域中山区,夏季降水量从东向西呈减少趋势,递减率约为80 mm·（100 km）^-1;最大降水高度带位于海拔4 500－4 700 m左右,年降水量为485 mm,该高度带与本区最大相对湿度高度层（海拔4 600 m左右）以及夏季气温零温层高度（海拔4 680 m左右）相一致.研究区域2008年夏季的凝结高度大致位于海拔4 900 m左右,个别降水日的凝结高度可降至海拔4 460 m左右.在最大降水高度带以下的高山和中低山区,年降水量随海拔升高的递增率为17.2 mm·（100 m）^-1,夏季降水量的递增率为11.5 mm·（100m）^-1.

1960-2012年河西内陆河上游山区降水量变化及其区域性差异分析

基于我国河西内陆河流域有关水文、气象台站的观测数据,对1960年代以来河西走廊的石羊河、黑河、疏勒河三大内陆河水系上游山区降水变化特征、趋势及区域时空变化差异进行了分析.结果表明:受全球变暖的影响,石羊河、黑河、疏勒河流域上游的降水量年代际、年际及季节性的变化总体上呈增加的态势,但不同区域降水增幅存在着一定的差异.其中,1960年代,位于祁连山东部的石羊河水系上游山区、中部的黑河水系上游山区及西部的疏勒河水系上游山区普遍少雨;1970年代,石羊河山区降水偏多并持续至今,黑河、疏勒河水系上游山区则降水偏少;1980年代,三大水系上游山区均多雨;1990年代的黑河、疏勒河山区和2000年代的三大水系上游山区均多雨;2010年以来,黑河山区降水偏少,石羊河与疏勒河山区降水均偏多.相对而言,位于祁连山西部山区的疏勒河水系上游年降水量与夏季降水量的增长较为显著.

河西内陆河流域冰川融水近期变化

基于第一次中国冰川编目数据库,以国家气象台站的月降水与月气温资料为驱动数据,利用度日模型重建了河西内陆河流域各水系1961～2006年冰川物质平衡和融水径流序列,并与短期观测资料的对比验证表明,模型具有较高的可信度。河西内陆河流域1961～2006年平均冰川物质平衡为-49.5 mm/a,从东段石羊河流域到西段疏勒河、党河流域,物质平衡由强烈的负平衡向微弱的负平衡状态过渡。整个河西内陆河流域1961～2006年平均冰川融水径流量为10.2亿m3,冰川融水补给比重为14.1%。各流域冰川融水补给比重差异较大,西段的疏勒河、党河融水补给比重超过30%;北大河流域为22.9%;黑河流域各支流的融水补给比重在5%～15%之间;东段的石羊河流域融水补给率不到10%。46年冰川融水径流与其补给率均呈显著的增加趋势。

甘肃河西地区内陆河流域荒漠化的水资源问题

河西地区内陆河流域荒漠化的水资源问题,根本的原因在于水资源短缺而导致的生态环境脆弱和水资源的过度开发利用.如果上、中游地区水资源的利用超过了水资源量的限度,则流到下游的径流量减沙,地下水位下降;而下游地区为了弥补水资源的不足,便大量开采地下水,致使地下水严重超采,从而导致植被退化和荒漠化.在分析上述问题的基础上,以石羊河为例,说明内陆河流域的荒漠化防治要求实行以农业节水为中心,建立节水型社会的流域综合治理,实现水资源、土地资源、经济、社会和生态环境协调和可持续发展.

祁连山西段党河山区流域气候变化及其对出山径流的影响与预估

依据祁连山西段党河山区气象台站的气温、降水和出山口水文站的径流等观测数据,分析1960-2010年51a来党河出山径流量的变化特征、趋势及其对气候变化的响应.结果表明:近51a来,党河山区气候转暖湿明显,气温上升,降水量增加、冰川消融增加.受山区气候变化影响,出山径流量总体亦呈增长趋势.从径流的补给来源与季节水量变化上讲,与主要受降水影响的河西走廊中、东部的黑河、石羊河水系不同,由于党河河源分布的冰川面积较多、个体较大,冰川融水受气温变化的影响更甚于降水.预计在未来几十年内,山区气候继续受向暖湿转化的影响,党河出山径流量呈持续增长的可能性较大.