GIS-Based Risk Assessment of Debris Flow Disasters in the Upper Reach of Yangtze River

This paper discussed theory and methodologies of debris-flow risk assessment and established an implementation process according to indicators of debris-flow hazard degree, vulnerability, risk degree, etc. Among these methodologies, historical and potential hazard degree was comprehensively considered into hazard assessment and hazard index was presented to indicate the debris-flow hazard degree. Regarding debris-flow vulnerability assessment, its statistical data and calculating procedure were based on the hazard-degree regionalization instead of administrative divisions, which improved the assessing scientificity and precision. These quantitative methodologies integrated with Geography Information System （GIS） were applied to the risk assessment of debris flows in the upper reach of Yangtze River. Its results were in substantial agreement on investigation data and the actual distribution of debris flows, which showed that these principles and methodologies were reasonable and feasible and can provide basis or reference for debris-flow risk assessment and disaster management.

Land Use Change During 1960～2000 Period and itsEco-environmental Effects in the Middle and UpperReaches of the Yangtze River:a Case Study in YiliangCounty,Yunnan,China

Land use/land cover change (LUCC) is a focus of the research of global environmental changes. The middle and upper reaches of the Yangtze River, which are the most ecologically fragile mountainous area in China as well as one of the areas in China with most notable LUCC, have been on the Chinese Government's list of priority areas for ecological restoration. This paper is to reveal the trend of LUCC and the ecological degradation arising from it, and to provide a basis for the future sustainable use of land resources in the region based on a detailed analysis of Yiliang County. Based on the county's land use/cover maps in 1960, 1980 and 2000 drawn with the aid of aerial photograph interpretation, field investigation and GIS based spatial-temporal data analysis, LUCC during 1960~2000 period and the ecological degradation arising from it were analyzed. Using the Markv model, the paper brings out a forecast of what the county's LUCC would be like if the county's current land use continues, as well as the reasons and countermeasures for restoring degraded ecosystems.

The SIA method for spatial analysis of precipitation in the upper-middle reaches of the Yangtze River

Using geographic information system (GIS) techniques and the newest seasonal and annual average precipitation data of 679 meteorological stations from 1971 to 2000, the multiple regressions equations of the precipitation and topographical variables are established to extract the effect of topography on the annual and seasonal precipitation in the upper-middle reaches of the Yangtze River. Then, this paper uses a successive interpolation approach (SIA), which combines GIS techniques with the multiple regressions, to improve the accuracy of the spatial interpolation of annual and seasonal rainfall. The results are very satisfactory in the case of seasonal rainfall, with the relative error of 6.86%, the absolute error of 13.07 mm, the average coefficient of variation of 0.070, and the correlation coefficient of 0.9675; in the case of annual precipitation, with the relative error of 7.34%, the absolute error of 72.1 mm, the average coefficient of variation of 0.092, and the correlation coefficient of 0.9605. The analyses of annual mean precipitation show that the SIA calculation of 3-5 steps considerably improves the interpolation accuracy, decreasing the absolute error from 211.0 mm to 62.4 mm, the relative error from 20.74% to 5.97%, the coefficient of variation from 0.2312 to 0.0761, and increasing the correlation coefficient from 0.5467 to 0.9619. The SIA iterative results after 50 steps identically converge to the observed precipitation.

A Preliminary Study on the Rational Utilization of Land Resources in the Poverty-Stricken Mountainous Areas in the Upper Reaches of the Yangtze River:A Case Study of Xueshan Township

As one of the most fragile alpine plateau and canyon areas in China,the upper reaches of the Yangtze River are the key areas of ecological construction in China.It is also a key area for poverty alleviation in the country.Therefore,it is necessary to take into account the dual goals of poverty reduction and ecological environment construction,and explore a win-win road of ecological construction and poverty alleviation in line with the reality of the upper reaches of the Yangtze River.Taking Xueshan Township,Luquan Yi and Miao Autonomous County,Yunnan Province,which is located in the poor mountainous area of the upper reaches of the Yangtze River as an example,based on many field investigations and existing investigation and statistical data,this paper analyzes the current situation and main problems of land use in Xueshan Township,and then puts forward measures and suggestions for rational utilization of land resources in Xueshan Township.This can provide a necessary reference for the next implementation of rural revitalization strategy and ecological construction.

Distribution Regularity of Debris Flow and Its Hazard in Upper Reaches of Yangtze River and Other Rivers of Southwestern China

In the upper reaches of Yangtze River and other rivers of southwestern China, the debris flows develop and lead to most serious disasters because of the various landforms, complex geological structures and abundant rainfall. The distribution of debris flows has regularity in the regions with different landform, geological structure, and precipitation. The regularities of distribution of debris flows are as following： （1） distributed in transition belts of different morphologic regions; （2） distributed in the area with strong stream trenching; （3） distributed along fracture zones and seismic belts： （4） distributed in the area with abundant precipitation; （5） distribution of debris flow is azonal. The activity of abundant debris flows not only brings harm to Towns, Villages and Farmlands, Main Lines of Communication, Water-Power Engineering, Stream Channels etc., but also induces strong water and soil loss. According to the present status of debris flow prevention, the problems in disasters mitigation and soil conservancy are found out, and the key works are brought up for the future disasters prevention and soil conservancy.

Analysis on River Sediment Changes of the Upper Reaches of Yangtze River

The sediment load and river sedimentation of the upper reaches of YangtzeRiver has been undergoing constant changes as complex landform, large mountain area and plentifulprecipitation make the drainage area of Yangtze River very vulnerable to watererosion and gravityerosion. Through analyzing the hydrological and sediment load statistics recorded by majorhydrological stations along Yangtze River since 1950s, and editing the accumulation graph of annualrunoff volume and annual sediment load, wefind out that the suspended-sediment of Yangtze river hasbeen decreasing year by year in Wulong Hydrological Station on Wujiang River, Beibei HydrologicalStation on Jialingjiang River, Lijiawan Hydrological Station on Tuojiang River and GaochangHydrological Station on Minjiang River, Yichang Hydrological Station, Cuntan Hydrological Stationalong Yangtze River mainstream share the same experience too. But the statistics obtained atPingshan Hydrological Station on Jinshajiang River shows the sedimentload there has increased.Taking ecological construction, hydraulic engineering construction and precipitation changes intoconsideration, the thesis analyses the causes for the sediment load decrease of Jialingjiang River,Tuojiang River, Minjiang River and Wujiang River and provides us both scientific foundation forfurther study of river sediment changes of the upper reaches of Yangtze River, and measures tocontrol river sedimentation.

长江中上游重要渔业水域环境质量评估

为准确评估长江中上游重要渔业水域水环境质量现状及变化趋势,提高水质评价效率,本研究基于11个水质参数,采用水质指数法(water quality index,WQI)对2006-2021年长江中上游三个重要渔业水域水质进行了综合评价,建立WQI min综合评价模型。结果显示:(1)长江中上游重要渔业水域的水温和高锰酸盐指数呈上升趋势;基于地表水环境质量标准(GB38338-2002),单因素水质评价结果表明监测水域内整体水质处于地表水Ⅴ类水标准,部分年份达劣Ⅴ类,主要污染指标为总氮。(2)通过综合评价方法分析,长江中上游重要渔业水域整体为“良”;2006~2021年长江中上游重要渔业水域水质质量呈逐年改善的趋势,且上游保护区的改善较大。(3)基于WQI方法,确定了长江中上游重要渔业水域的关键水质参数为:总氮、高锰酸盐指数、汞、溶解氧、氨氮、悬浮物以及水温,分别构建了上游保护区、中华鲟保护区以及四大家鱼保护区的WQI_(min)模型;考虑权重和不考虑权重的WQI min模型对比分析表明,考虑权重的WQI min模型的水质评价结果更加准确,该方法可有效评估长江中上游重要渔业水域的水质变化特征并可扩展用于其他水域。

Features and Sources of the Anomalous Moisture Transport for the Severe Summer Rainfall over the Upper Reaches of the Yangtze River

Using the daily NCEP/NCAR reanalysis dataset and the observation rainfalldata in China for the 1980-1997 period, features of severe summer rainfall over the upper reaches ofthe Yangtze River are investigated and then sources of moisture contributing to severe rainfallover eastern and western Sichuan Province (ES and WS for short) are examined with particularreference. It turns out that the severe rainfall occurring locally dominates summer rainfall overthe upper reaches of the Yangtze River. Climatological rainfall and anomalous one constitute severerainfall, but the latter accounts much for severe rainfall. The meridional moisture transportdominates the composite moisture transport on the occurrence day for ES region, while the zonal isequivalent to the meridional for WS region. Correlation between the moisture transport fluxes overthe two regions of severe rainfall and other regions, the anomaly and variation of the moisturetransport day by day during the period of severe rainfall lend a support for the conclusion that themeeting of the moisture from the West Pacific through the South China Sea (SCS) and the one fromnorthwestern China exerts a vital effect on the occurrence of severe rainfall, which can not beneglected.

长江上游潜流带泥沙中石油烃吸附机理研究

生态优先、绿色发展是推动长江经济带发展必须坚持的战略定位,然而随着长江航运的迅猛发展,大量船舶溢油污染物在长江潜流带沉积,威胁生态安全。为研究船舶溢油在长江上游潜流带中的吸附规律,本研究选用长江航运广泛使用的0号柴油为实验用油,以长江上游潜流带泥沙为研究对象,通过室内平衡振荡实验分析不同浓度水溶态石油烃在不同粒径泥沙中的吸附机理。结果表明:长江上游潜流带泥沙颗粒对水溶态石油烃的吸附平衡时间均在2 h左右,吸附过程呈明显的二阶段特征,包括快速(0~1 h)和慢速(1~2 h)两个阶段,快速阶段吸附量在90%以上,吸附量与粒径大小关系显著,准二级动力学模型(R^(2)为0.995~0.997)拟合效果更好。潜流带泥沙吸附过程呈线性趋势特点明显,Henry线性等温吸附模型(R^(2)为0.918~0.996)对等温吸附实验结果的拟合度更高,呈现出强分配、弱吸附的特点。大多情况下石油烃浓度越高、泥沙粒径越小,泥沙单位吸附量则越多,但有机质含量的差异会影响这一规律;此外,水土比降低、盐度升高会使泥沙单位吸附量增加。研究显示,长江上游潜流带泥沙对水溶态石油烃的吸附速率主要受到化学吸附机理控制,以表面有机质溶解分配作用为主,以非均匀表面化学吸附为辅,石油烃浓度、泥沙粒径、水土比、盐度均对石油烃在潜流带中的吸附有一定影响。

长江上游典型深潭生境健康评价研究

作为水生态保护与修复的重要理论,鱼类栖息地健康评价一直是研究重点,但缺少量化综合评价的深入研究。以长江上游中的5处典型深潭生境为例,构建了鱼类栖息地健康状况量化评价体系。研究通过长江上游典型深潭生境健康评价(一级指标)为基准,分为了栖息地环境和栖息地功能(二级指标),涵盖了水质特性、生物环境、水文环境、鱼类资源状况、栖息地质量5个三级指标以及29个四级指标,基于熵权法构建栖息地健康综合评价数学模型,通过栖息地健康综合指数(Comprehensive Health Indicator,ρ)表征典型栖息地健康状态,并对其健康状况进行综合评价。研究结果表明:长江上游典型深潭生境有1处健康等级评价为Ⅰ级,处于非常健康状态;3处评价为Ⅱ级,处于健康状态;1处评价为Ⅲ级,处于亚健康状态,无不健康或劣汰的点。总体来看,长江上游典型栖息地基本处于健康状态,且表现出较强的空间异质性,该评价结果在一定程度上客观反映了长江上游典型栖息地的健康状况,最后根据评分等级探讨了长江上游鱼类栖息地生态系统中亟需解决的问题,针对性地提出了生境修复的对策与建议。

基于CMIP6多模式集合对长江上游地区暴雨的预估研究

为更好地应对长江上游地区未来气候变化导致的暴雨事件,本文利用1990-2014年长江上游地区687个气象观测站日降水资料及第六次耦合模式比较计划(Coupled Model Intercomparison Project Phase6,CMIP6)中的24个全球气候模式的模拟结果,研究了该地区2021-2099年的年平均暴雨量、暴雨天数和暴雨强度在不同共享社会经济路径(Shared Socioeconomic Pathways,SSPs)情景下的时空变化特征及其不确定性。研究结果表明:(1)相对参考时段(1995-2014年),长江上游地区预估总时段(2021-2099年)及21世纪末期(2080-2099年)的年平均暴雨量、暴雨天数和暴雨强度在SSP1-2.6、SSP2-4.5和SSP5-8.5情景下都以增多增强为主,在SSP5-8.5情景下的增幅最大,且模式间预估方向的一致性及预估值的确定性都随排放的增加而增加。预估总时段的暴雨量、暴雨天数和暴雨强度在SSP1-2.6和SSP2-4.5情景下的分布相似,但与SSP5-8.5情景下的分布有所不同。21世纪末期暴雨量及天数在三种情景下的分布相似,暴雨强度变化的分布在SSP5-8.5情景下不同于SSP1-2.6及SSP2-4.5情景;(2)相对参考时段,三种情景下长江上游的暴雨量在预估总时段分别以3.5 mm·(10a)^(-1),5.4 mm·(10a)^(-1),14.7 mm·(10a)^(-1)的速率增加,暴雨天数分别以0.045 d·(10a)^(-1),0.07 d·(10a)^(-1),0.18 d·(10a)^(-1)的速率增加,暴雨强度则分别以0.37 mm·d^(-1)·(10a)^(-1),0.78 mm·d^(-1)·(10a)^(-1),1.94 mm·d^(-1)·(10a)^(-1)的速率增强,都通过99%信度检验及同号率检验,预估值确定性较高的时期都出现在21世纪末期SSP5-8.5情景下;(3)三种情景下,预估总时段的暴雨量、暴雨天数和暴雨强度在空间上都主要呈增加趋势,其中藏东南地区的暴雨量及暴雨天数的增速最大。暴雨强度增速最大的地区在SSP1-2.6情景下出现在四川北部,而SSP2-4.5和SSP5-8.5情景下出现在云南北部;(4)三种情景下21世纪前期(2021-2040年)暴雨量、暴雨天数和暴雨强度相对参考时段的变化幅度不明显,中期(2041-2060年)及后期暴雨量、暴雨天数和暴雨强度在SSP2-4.5及SSP5-8.5情景下显著增多增强,尤其在21世纪后期SSP5-8.5情景下的增幅最大,模式间预估方向一致性最高。

基于土地利用变化的长江上游生态系统服务价值核算及预测模拟

为研究长江上游地区土地利用变化对生态系统服务价值(ESV)的影响,基于GIS网格空间可视化表达技术,以土地利用和社会经济为数据源,采用土地利用动态度、ESV评估模型和空间自相关模型等方法,对研究区土地利用动态度和ESV时空变化特征及二者的相关性进行研究。结果表明,1)长江上游地区林地和草地是最主要土地利用类型,2000-2020年,林地、水域、建设用地、未利用地面积呈现增加趋势,其中建设用地面积在2020年较2000年增加148.66%,耕地和草地的面积呈现减少的趋势;2)在2050年未来气候情景下各类型土地利用变化差异较为显著,耕地、水域、建设用地和未利用地面积均减少,变化速度最快的是水域,而林地和草地面积呈增大趋势,未来2个不同气候情景下的土地利用综合变化速度稳定在0.80%~0.92%;3)长江上游地区土地利用存在很大开发潜力,2000-2020年及2050年未来气候情景下土地开发以中低强度为主,而高强度等级土地利用聚集分布于四川和重庆,特别在2050年未来2个气候情景下区域极核分布更为显著,需引起高度重视;4)研究区单位面积ESV以中和较高等级为主,总ESV稳定在80000亿元以上,呈先增后减的趋势,但空间分异较为显著,其中长江上游中部山地以及青藏高原部分区域单位面积生态系统服务价值较高,而四川、重庆主城区是较低和低级生态系统服务的集中分布区域,在未来气候变化下ESV呈下降趋势,中等排放情景ESV小于低排放情景ESV;5)ESV与综合土地利用强度呈正相关性,空间上主要以高-高聚集、高-低聚集和低-低聚集分布为主,高-高型主要分布于青藏高原和横断山脉的部分地区,高-低型集中分布于经济发展较快的四川、重庆地区,低-低型分布于草地广泛、经济发展较为落后的青藏西北地区。研究结果揭示了长江上游地区2000-2020年及未来气候变化下ESV与土地利用动态的时空演变规律及其相关性,可为制定科学合理的地区生态保护政策、建立生态保护修复的长效机制提供科学依据。

Conservation and Sustainable Exploitation of Forest Ecosystem in Upper Reaches of the Yangtze River -Case Study on Gongga Mountain

The deforestation on large scale in the upper reaches of Yangtze River has caused serious problems of ecosystem and environment. Restoration of the degenerated forest ecosystems is one of the main research fields. Taking Gongga Mountain as an example, degeneration features and existing problems of forest ecosystems are analyzed in this paper, and the measures are also proposed.

晚清长江中上游民船运输状况——以《长江三峡及重庆游记》为中心的考察

1883年英国商人立德乐通过实勘实测的方法记录了其在长江中上游流域乘坐民船的航行情况,并留下数万字的旅行记录——《长江三峡及重庆游记》,生动再现了晚清我国长江中上游流域传统民船的运输状况。通过对行记的考察可以厘清我国民船的运输情形,自从清代前期长江流域全面贯通以来,逐渐积累了成熟的造船技术、完善的民船运营结构、丰富的行船经验等,都促进了长江民船运输专业化,高效率水运系统的形成。与近代轮船运输相比,传统民船在运输价格、航行范围、运营的灵活性上都具有优势,即使在晚清长江中上游开通轮船运输后,民船运输仍在持续发展。

基于文献计量分析的长江中上游鱼类资源研究综述

针对长江中上游鱼类资源领域研究,以主题“长江上游”“长江中游”“金沙江下游”“鱼类资源”“鱼类早期资源”为检索条件,筛选了2023年7月前中国知网及Web of Science核心合集数据库收录的503篇文献,利用CiteSpace进行文献计量分析并绘制科学知识图谱,在此基础上从文献数量分布、研究机构及代表作者分布、研究主题内容、研究热点及演变趋势方面对长江中上游鱼类资源领域研究进行了综述。结果表明:中国科学院和中国水产科学研究院等是该领域的领军机构;从发展趋势上看,该领域已形成了鱼类资源现状及变化趋势、鱼类资源的影响机制以及鱼类资源的保护对策3个重要的研究热点和方向。后面需进一步完善江段鱼类资源的长期动态监测方法、梯级开发背景下鱼类资源的变动情况以及鱼类资源的协同保护方法等方面的研究。

长江上游保护区重庆段鱼类重要栖息地水环境及鱼类分布特征研究

为探究长江上游珍稀特有鱼类国家级自然保护区(以下简称“保护区”)重庆段鱼类重要栖息地(产卵场、索饵场和越冬场)的水环境及鱼类分布特征,本研究分别于2021年冬季(越冬期)、2022年夏季(产卵期)、2022年秋季(索饵期)在保护区重庆段设置羊石(S_(1))、松溉(S_(2))、白沙(S_(3))、油溪-龙华(S_(4))、江津城区(S_(5))、珞璜(S_(6))等6个调查江段,开展3次水声学调查并分析各江段的水质状况。水声学调查结果表明,3次探测鱼类的平均密度相差不大,分别为0.584、0.590、0.595 ind./m^(2),所探测的重要栖息地以古家沱、丁家沱、江口、王家沱等产卵场鱼类分布较多。鱼类密度在不同江段存在显著性差异(P<0.05),整体表现为下游高于上游;重要栖息地鱼类密度在不同江段存在显著性差异(P<0.05),而在不同时期差异不显著(P>0.05),且整体明显大于非重要栖息地。水质监测结果表明,上、下游水质差异不明显,7个水质指标中除总氮外其余指标均达到Ⅲ类地表水标准,符合渔业水质要求。综上,保护区重庆段鱼类重要栖息地水质状况良好,能满足鱼类生长繁殖的需要。

三峡水库秋汛期水沙特点及秋汛洪水对库区冲淤的影响

长江上游秋汛洪水是三峡水库重要水沙事件,对三峡库区冲淤特性有直接影响。基于1954-2022年实测资料分析表明,近70年来长江上游秋汛期来水量变化不大,来沙量均值在2013年前后减幅达到87%。2013年以后,三峡库区秋汛洪水的来沙高度集中于嘉陵江流域,占寸滩沙量的70%以上,秋汛洪水通过影响嘉陵江的水沙条件,进而间接影响三峡水库秋汛期的入库水沙条件。与汛期洪水相比,秋汛洪水的泥沙90%以上在库区淤积,且库尾淤积更加突出。实测资料分析结果表明,秋汛洪水期间适时加大水库下泄流量,可显著增大排沙量,减轻库区淤积。研究成果对加深三峡水库淤积特性认识、优化三峡水库秋汛洪水调度具有重要意义。

1990—2020年长江上游“三生”空间转型的生态环境效应及其空间分异机制

[目的]探究“三生”空间转型的生态环境效应及其空间分异机制,可为协调土地高效利用与社会生态可持续发展提供科学依据。[方法]以长江上游地区为研究对象,采用土地利用转移矩阵、生态环境质量指数对1990—2020年长江上游地区“三生”空间转型规律、生态环境效应的空间分异特征进行定量分析,并结合地理探测器模型识别生态环境质量空间分异的驱动因素。[结果](1)长江上游地区“三生”空间格局分异显著,生态空间广泛分布于流域的西部和南部区域;生产空间集聚在成都平原以及散布在河网水系密集、利于耕作的山间盆地;生活空间以零星状分布在昆明、成都、重庆等中心城市。(2)生态环境质量总体保持稳定并以较高质量为主,生态环境质量空间格局分布呈中间低、四周高的分布格局,低质量区以团块状和条带状分布在四川盆地和横断山脉北侧,中、高质量区主要分布在长江上游地区外围、西南部和南部区域。(3)农业生产空间转化为林地生产空间、水域生态空间,以及草地生态空间转化为林地生态空间是促使生态环境质量改善的主要土地转化类型;相反,生态环境质量恶化与林地生态空间转化为农业生产空间、草地生态空间及工业生产空间紧密相关。(4)地形起伏度、坡度、人口密度以及土地利用强度是影响生态环境质量空间分异的主要驱动因子,自然因素和社会因素的交互作用共同影响长江上游地区生态环境质量。[结论]长江上游地区生态环境质量总体保持稳定,但局部生态环境恶化趋势不容忽视,在未来政策制定中,应根据各地区的自然条件、主体功能定位以及生态环境承载等实际情况优化“三生”空间用地结构。

长江上游重庆段近20 a降水时空变化特征

全球气候变暖背景下,我国降水分布日趋复杂,气象灾害造成的损失巨大。为满足防灾减灾与水资源管理的数据支撑需求,基于长江上游重庆段近20 a降水数据,利用线性回归、M-K非参数检验等方法,探究降水的时间变化趋势与空间分异特征。结果表明:近20 a重庆市年降水量在875.6—1348.2 mm。时间上,春、秋两季呈明显增多的趋势,其中3月最显著。降水在14 a时间尺度的周期过程线中波动最强,是第一主周期。空间分布上,呈西低东高的特点,在渝西和长江河谷地区降水相对偏少,主要受重庆地形的影响;渝西和渝东北地区秋季降水显著增多。研究结果可为长江流域旱涝灾害防治、水资源开发利用及经济社会可持续发展提供数据支撑,同时可为植被修复与生态廊道保障提供参考。