Residents’ perspectives and responses to environmental degradation in the upper Dadu River, eastern Tibetan Plateau

Environmental degeneration in the Tibetan Plateau attracts worldwide attention, whereas case studies on how the residents understand and respond to environmental degeneration are scarce. Using a Participatory Rural Appraisal method, this paper investigates how the people in different regions in the upper Dadu River understand and respond to environmental degeneration, based on comparative field surveys in three villages, in which Danzamu village is chosen from villages in the valley region, Kerma village from mountainside region, Rico village from the mountain and plateau region. The results show that： （1） although awakened to environmental degeneration, the residents in different regions have different responses. As agricultural labors have been transferred to the secondary and tertiary industries, population pressure in Danzamu and Kerma villages is mitigated. Residents in Danzamu village actively respond to natural disasters and forest degradation, as their livelihoods never rely on forests and rangelands again. Whereas the residents in Kerma village negatively respond to natural disasters, forest and meadow degradation and the ruin of wildlife resources, as their livelihoods still rely on stockbreeding. Labors in Rico village are hard to transfer to the secondary and tertiary industries, so they have to raise more livestock to make a living. Active measures are just taken to avoid livestock loss, not to avoid forest and meadow degradation and the ruin of wildlife resources. So the most fragile region is the mountain and plateau region and mountainside region, not the valley region. （2） Livelihood strategy is the key factor affecting the residents to respond to population pressure and environmental degeneration. So the framework of sustainable livelihood strategy should be used to explain and intervene in issues of population pressure and environmental degradation in ecotones. （3） Transferring agricultural labors to the secondary and tertiary industries were favorable to improving people＇s livelihood. It is necessary to reduce the education fees to speed up the pace of labors transferring in the mountainside region. In the mountain and plateau region, preferable ways also include the development of towns, highways, education equipment and other establishments.

Livelihood Strategy Change and Land Use Change——Case of Danzam Village in Upper Dadu River Watershed,Tibetan Plateau of China

Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population increase, has received more attention. However, case studies on how institution reforms affect farmers’ livelihood strategies and drive land use change are scarce. By means of cropland plots investigations and interviews with farmers, this study examines livelihood strategy change and land use change in Danzam Village of Jinchuan County in the upper Dadu River watershed, eastern Tibetan Plateau, China. The results show that, during the collective system period, as surplus labor forces could not be transferred to the secondary and tertiary industries, they had to choose agricultural involution as their livelihood strategy, then the farmers had to produce more grains by land reclamation, increasing multiple cropping index, improving input of labor, fertilizer, pesticide and adopting advanced agricultural techniques. During the household responsibility system period, as labors being transferred to the secondary and tertiary industries, farmers chose livelihood diversification strategy. Therefore, labor input to grain planting was greatly reduced, which drove the transformation of grain to horticulture, vegetable or wasteland and decrease of multiple cropping index. This study provides a new insight into understanding linkages among institution reforms, livelihood strategy

An integrated north–south paleo-Dadu-Anning River: New insights from bulk major and trace element analyses of the Xigeda Formation

The Xianshuihe-Anninghe fault extends SE–S and constitutes the southeastern margin of the Tibetan Plateau.However,the Dadu River which is associated with the fault does not flow following the path,but makes a 90ºturn within a distance of 1 km at Shimian,heading east,and joins the Yangtze River,finally flowing into the East China Sea.Adjacent to the abrupt turn,a low and wide pass near the Daqiao reservoir at Mianning separates the N–S course of the Dadu River from the headwater of the Anning River which then flows south into the Yunnan Province along the Anninghe fault.Therefore,many previous studies assumed southward flow of the paleo-Dadu River from the Shimian to the Anning River.However,evidences for the capture of the integrated N–S paleo-Dadu-Anning River,its timing,and causes are still insufficient.This study explored the paleo-drainage pattern of the Dadu and Anning Rivers based on bulk mineral and geochemical analyses of the large quantities of fluvial/lacustrine sediments along the trunk of the Dadu and Anning Rivers.Similar with sands in the modern Dadu River,the Xigeda sediments also exhibit a granitoid affinity with the bulk major mineral compositions of quartz(>50%),anorthite(about 10%),orthoclase(about 5%),muscovite(about 5%),and clinochlore(about 4%).Correspondingly,bulk major elements show high SiO_(2),with all samples>60%,and some of them>70%,low TiO_(2)(≤0.75%),P_(2)O_(5)(≤0.55%),FeO*(≤5%),and relatively high CaO(1.02%–8.51%),Na_(2)O(1.60%–2.52%),and K_(2)O(2.17%–2.71%),with a uniform REE patterns.Therefore,synthesizing all these results indicate that these lacustrine sediments have similar material sources,which are mainly derived from its course in the Songpan-Ganzi flysch block,implying that the paleo-Dadu originally flowed southward into the Anning River and provided materials to the Xigeda ancient lake.The rearrangement of the paleo-Dadu River appears to be closely related to the locally focused uplift driven by strong activities of the XianshuiheXiaojiang fault system.

Changes of wetland landscape patterns in Dadu River catchment from 1985 to 2000, China

Based on the interpretation and vector processing of remote sensing images in 1985 and 2000, the spatial changes of wetland landscape patterns in Dadu River catchment in the last two decades were studied using spatial analysis method. Supported by Apack soft-ware, the indices of wetland landscape pattern were calculated, and the information entropy （IE） was also introduced to show the changes of wetland landscape information. Results showed that wetland landscape in this region was characteristic of patch-corridor-matrix configuration and dominantly consisted of natural wetlands. Landscape patterns changed a little with low fragment and showed concentrated distribution with partial scattered distribution during the period from 1985 to 2000. The values of patch density and convergence index kept stable, and the values of diversity, evenness indices decrease, while dominance and and IE showed a slight fractal dimension indices were increased. All types of wetland landscapes had higher adjacency probabilities with grassland landscape in 1985 and 2000, and there was extremely weak hydrological link and large spatial gap among river, glacier, reservoir and pond wetlands due to low adjacency matrix values. Since their cumulative contribution exceeded 81% through the PCA analysis, the agriculture activities would be the main driving force to the landscape changes during the past 15 years.

Exploration and practice of intelligent engineering in Dadu River hydropower construction

In view of the difficulties in promoting intelligent management in the field of engineering construction,based on the concept of intelligent enterprise and the actual situation of hydropower project-construction management,this paper puts forward the basic concept,main features and general idea of intelligent engineering.Based on a review of the exploration,pilot construction and comprehensive practice of intelligent engineering in the hydropower construction of Dadu River,the practical results of the intelligent engineering of Dagangshan,Houziyan,Shaping-II and Shuangjiangkou hydropower stations are summarized.The technical system and management model of engineering an early-warning decision centre,intelligent dam project,intelligent underground project,intelligent electromechanical project,intelligent security control,intelligent service guarantee,intelligent environmental and water protection,and intelligent resource control in Shuangjiangkou hydropower station are introduced.It is proposed that intelligent engineering is a high integration of information technology,industrial technology and management technology.And it is pointed out that intelligent engineering will lead in the new development of water conservancy and the hydropower industry,and even the engineering-construction field,throughout the world.

Land cover changes based on plant successions: Deforestation, rehabilitation and degeneration of forest in the upper Dadu River watershed

To link regional land use/cover changes with environmental effects, land cover changes are required to reflect vegetation successions, whereas the land cover classification systems commonly used nowadays cannot serve this purpose. In this paper, a new land cover classification system is established in which land covers are classified by the vegetation succes-sions, taking Zamtang County, Barkam County and Jinchuan County in the upper Dadu River watershed as a study area. Using multi-temporal remote sensing images, the land cover data of 1967, 1986 and 2000 are obtained by means of integration of unsupervised classification and visual interpretation methods. The database facilitates the study of land use/cover changes, en-vironmental effects and ecological construction. Land cover changes reflect the main ecological processes in the upper Dadu River watershed. The landscape composed mainly of grasslands, wildwoods and alpine scrubs in 1967 was changed to that of grasslands, secondary forests, al-pine scrubs, fragmentary wildwoods, artificial forests, secondary scrubs in 2000, meanwhile, the landscape got more fragmentized. The total area of the forests decreased by 9.43%. Study results have shown the process of restoration of logged areas in forest centers. From 1967 to 2000, only 6.86 percents of logged areas were converted to shrubs, meadows or crop-lands, and the rest were converted into artificial forests or secondary forests. So the ecological shelter functions will be restored, stage by stage. Firewood collection, charcoal production and overgrazing are the three major triggers for the extensive degradation of alpine oak forests, Sa-bina tibetica forests and meadows. The arid valley grasslands expanded too. The degradation of vegetation in the southern slopes impairs ecological shelter functions and affects livelihood of local residents, so it is essential to find effective measures for ecological restoration and recon-struction. Field investigations have found that the current measures have not concerned with how to keep the livelihood of local farmers and herders. The most important measure for ecological protection and restoration is to help the farmers and herders to raise the living standard, which means that they will never need to rely only on the colonizing of croplands, the logging of forests and the grazing of livestock to make a living.

大渡河上游阿娘寨古堰塞湖的发现及其特征

古堰塞湖的沉积特征研究是开展堰塞湖古环境、古气候研究的基础。大渡河上游小金川两岸多地出露粉砂质黏土、砂和砾石构成的堰塞湖剖面,通过沉积学分析、光释光测年以及对堵江坝体的岩性构造分析,认为小金川在距今(15.7±1.9)~(9.1±1.0)ka期间发生了一次重大的堵江—堰塞—溃决事件,且该古堰塞湖的沉积环境随时间和空间的变化发生迁移:时间上,堰塞湖经历了形成、充填和溃决3个阶段;空间上,从下游至上游划分出深—半深湖、浅湖、滨湖和河湖交汇区4个沉积区,该古堰塞湖是由阿娘寨古滑坡堵江形成,据此命名为阿娘寨古堰塞湖。该古滑坡主要受控于岩性和构造作用。本次研究进一步丰富了青藏高原东南缘山区大型古堰塞湖的研究成果,其沉积特征、年代和成因特征为后续的深入研究提供了基础材料。

泸定地震大渡河区域灾害调查及格林函数库应用可行性探讨

2022年9月5日,四川省甘孜州泸定县发生M_(S)6.8地震,造成了较为严重的人员伤亡.震后中国地震局地球物理研究所科考队对泸定M_(S)6.8地震中大渡河干流上的几座梯级水电站和极震区等附近区域进行了灾害调查.调查结果表明梯级电站在本次地震中受影响较小,不影响正常运转.地震发生后,我们也采用经验格林函数方法并考虑震源参数的不确定性特征,对震区的石棉擦罗地区(位置①)、大渡河流域兴康高速特大桥区域(位置②)、历史地震古滑坡—摩岗岭附近区域(位置③)等三个典型位置合理范围的地震动加速度时程进行了快速估计.初步结果表明:位置①和③建筑物存在被本次地震破坏的可能性;位置②桥梁受地震破坏的可能性较小.最后,结合本次灾害调查结果、工程自建地震监测台网、典型位置地震动快速估计的结果,本文对重点工程区域建设基于实际小震波形的格林函数数据库应用前景的可行性进行了探讨.

大渡河干流已建水电站生态基流目标值复核分析

以大渡河干流已建水利水电工程为研究对象开展回顾性评价,为推动后续生态基流研究和水资源管理提供参考。研究采用多种水文学方法,包括Tennant法、Texas法、Q90法、多年最小月平均流量法和NGPRP法,计算大渡河干流已建梯级水电站的生态基流目标值。根据计算结果中各控制断面的最小值、最大值和平均值,建立生态基流目标值的参考区间,分别对应底线、优和良好的标准线,并对大渡河干流已建梯级水电站生态基流目标进行了回顾性评价。结果表明,大多数断面的现行生态基流目标值均在最大和最小参考值区间范围,设置基本合理。针对不同历史条件下或不同行业领域中存在的生态基流相关概念内涵和适用边界条件的不一致问题,以及拦河工程生态基流调度的实际问题,研究提出生态基流目标体系的双指标控制法,并提出了大渡河干流已建梯级水电站生态基流目标建议值,建议双江口、猴子岩、深溪沟、龚嘴、铜街子水电站的生态基流目标采用日均和瞬时双控值,分别设为121/52、160/78、327/188、366/149和366/236 m^(3)/s,而沙湾和安谷水电站均设为366 m^(3)/s。

基于积雪数据的HBV模型改进及应用

大渡河流域内站点分布较少,历史观测数据不足,给该地区的融雪径流预报带来困难。基于欧洲中期天气预报中心提供的最新一代高分辨率陆面再分析数据集ERA5-Land,将积雪覆盖率和积雪平均深度引入度日因子雪量计算公式中,对HBV模型的积融雪模块进行改进,以提升融雪径流计算的可靠性。以大渡河上游为研究对象,选取1961—2018年的水文气象资料对模型进行率定和验证,并以2019年为例进行试预报研究。结果表明,通过引入ERA5-Land再分析数据,以及对积融雪模块进行改进,发挥了其在模拟积融雪上的优势,有效提升了融雪径流预报精度,对大渡河流域具有适用性。研究成果可为稀缺资料地区融雪径流模拟预报提供经验。

大渡河上游玛柯河至脚木足河段浮游植物群落特征调查

为了解大渡河上游水域生态环境现状,该研究于2017-2018年春冬季2次对大渡河上游玛柯河至脚木足河段浮游植物进行收集分析,查明了浮游植物的动态变化和群落结构特征。结果显示,此次调查水域的浮游植物共鉴定出102种(属),隶属于6门46属。其中硅藻门占绝对优势,有76种(属),占浮游植物总物种数的74.5%。各河段春季的浮游植物平均密度和生物量比冬季都有显著的增加,分别增加了3.7和2.8倍,但总体呈现低密度和低生物量的特征。为获得该水域浮游植物本底资源现状及水生态监测提供了基础数据。

大渡河泸定县段水环境质量分析

掌握大渡河泸定县段水环境质量整体情况和变化趋势对于更好的保护大渡河中游开始段水质,更有针对性的提出水污染防治措施很有必要。以大渡河泸定县段入境上游断面及其出境断面水质的例行监测数据为依据,利用单因子评价法、内梅罗指数法和Spearman秩相关系数法对大渡河泸定县段水质进行分析评价。结果表明2018—2022年,泸定县出境断面水质好于入境上游断面水质,泸定县出境断面水质呈逐年向好的趋势,于2021年水质趋于平稳,其总磷和高锰酸盐指数浓度为丰水期>平水期>枯水期,各月份中6—8月水质相对差些。2017—2022年,其出境断面高锰酸盐指数浓度下降趋势具有显著意义。系统地对大渡河泸定段水质情况和变化趋势开展分析,可为地方政府开展大渡河水环境保护工作提供数据支撑。

大渡河流域中高山区农村生活污水治理模式初步研究--以汉源县为例

根据大渡河流域中高山地区农村生活污水点多面广、污水来源分散、间隙性排放,且统一纳管进入城镇污水处理厂集中处理难度大的特点,本文以汉源县农村生活污水治理模式为例,考察了其污水处理设施处理效果,并对运维费用进行了分析。结果表明,本案例厌氧+芦苇湿地组合工艺能满足四川省地方标准《农村生活污水处理设施水污染物排放标准》(DB 51/2626-2019)一级标准要求,化学需氧量(COD_(Cr))、氨氮(NH_(3)-N)及总磷(TP)3种污染物去除率分别达到52.2%~79.6%、46.0%~79.2%、33.2%~84.9%,年运维费比有动力设施具有明显优势。本案例可为大渡河流域中高山区农村生活污水治理提供参考。

大渡河乐山段2013-2016年浮游动物群落特征变化

为了解大渡河沙湾至乐山段安谷水电站建设过程中浮游动物群落变化,于施工期2013-2014年和运行期2015-2016年的每年春、秋两季对主河道、左侧河网及支流浮游动物群落进行监测。结果显示,2013-2016年调查共鉴定出浮游动物263种,优势种为12种属,旋轮虫属(Philodina)为施工期、运行期共有优势种属。浮游动物平均密度为658.55个/L,平均生物量为0.1102 mg/L;施工期和运行期浮游动物密度和生物量差异不显著,春季平均密度最高值出现在2014年(621.15个/L),秋季平均密度最高值出现在2015年(674.19个/L),2013年春、秋季的生物量均为最高(0.1324 mg/L、0.1070 mg/L),浮游动物密度和生物量在季节分布上差异不大。在空间分布上,支流高于主河道、左侧河网、岷江。施工期、运行期浮游动物密度、生物量与环境因子溶解氧(DO)、流速(V)呈负相关,与水温(WT)、氨氮(NH4+-N)、硝氮(NO3--N)、总氮(TN)、磷酸盐(H3PO4)、总磷(TP)、高锰酸盐指数(CODMn)呈正相关。RDA显示,NO3--N在2014年、2015年对浮游动物影响占主导作用,2016年透明度(SD)是影响浮游动物群落的主要因子。不同时期浮游动物现存量对比,蓄水期因水温偏低导致密度和生物量最低;在空间分布上坝前受安谷水电站建设影响较大。研究表明,安谷水电站在建设过程中浮游动物群落特征差异不大。

大渡河猴子岩水库入库洪水过程预报-实时校正-概率预报集成

与传统确定性预报相比,洪水概率预报能够为防洪调度决策提供更为丰富的信息。以大渡河猴子岩水库以上流域为研究区,建立新安江次洪模型,并采用动态系统响应曲线进行实时洪水预报校正。在确定性预报校正基础上,建立基于水文不确定性处理器(HUP)的次洪概率预报模型,定量分析预报不确定性,实现入库洪水概率预报。结果表明:①利用猴子岩流域20092019年水文气象资料,建立的新安江次洪模型整体精度较高,率定期和验证期的洪量和洪峰相对误差均在±20%以内,平均确定性系数分别为0.69和0.72;经动态系统响应曲线校正后,洪峰和洪量误差均有降低,率定期和验证期的确定性系数分别提高0.13和0.09。②以2020年3场洪水未来48 h预报降雨为输入,新安江模型预报精度不高,且随着预见期增长而降低,但经动态系统响应曲线校正后,整体预报精度有所提高,洪量相对误差减小幅度超50%,确定性系数提高幅度超60%。③HUP次洪概率预报模型提供的分布函数中位数Q50的预报精度在一定程度上优于校正后的确定性预报;提供的90%置信区间覆盖率均在90%左右,离散度均在0.40以下,能以相对较窄的区间覆盖大部分实测值,具有较高的可靠度。

大渡河流域融雪期划分方法研究

为准确判断融雪期起止时间,以大渡河融雪径流主要来源区的丹巴以上流域为例,基于2009~2020年的水文气象资料,分别采用集对分析法、系统聚类法和K-means聚类法对流域枯季(11月~次年5月)融雪期进行分期计算,并对分期结果进行合理性评估,确定流域最终融雪期划分方案。结果表明,大渡河丹巴以上流域的主融雪期为1月11日~5月10日,其前的11月1日~1月10日为退水期,其后的5月11日~5月31日为降雨径流开始期(仍有部分融雪径流)。研究结果可为高纬度地区的融雪期划分提供参考。

大渡河流域红色文化体育旅游带建设的思考

该文通过查阅文献、田野调研、访谈等方法,调查分析了大渡河流域红色文化体育旅游带资源分布情况。研究表明,大渡河流域长征红色文化资源、自然资源和体育旅游资源富集,但挖掘力度不够,区域内旅游开发以传统普通游览观光为主,且存在红色体育旅游发展不均衡等问题,提出深度挖掘大渡河流域长征红色文化资源、绿色自然资源、体育资源并进行梳理整合,放眼整个大渡河流域整体规划,打造以红色长征文化为内涵,绿色自然资源为牵引,体育旅游为主题的大渡河流域红色文化体育旅游带。

大渡河干旱河谷区林木种质资源现状及利用建议

林木种质资源是林业建设与发展的基础,关系到提高森林质量、丰富林业产品的需求。以普查、重点调查、访问、资料收集相结合的方式,在大渡河干旱河谷区丹巴县布设调查样线61条(线路总长度130 km),对全县12个乡(镇)的林木种质资源开展野外调查和数据分析,结果表明:(1)乔木、灌木、竹类和木质藤本等木本植物共计543种,其中灌木328种,占比60.40%;乔木175种,占比32.23%;木质藤本33种,占比6.08%;竹类7种,占比1.29%。(2)蔷薇科为区域最大优势科,共99种,占比18.23%;豆科31种,占比5.71%;忍冬科30种,占比5.52%;杜鹃花科27种,占比4.97%;杨柳科25种,占比4.60%。(3)从垂直分布来看,海拔2500 m以下,以旱生植被为主,适合发展林果产业;海拔2500 m以上,野生林木种质资源较为丰富。建议加大乡土树种、经济良种、彩叶树种的选育和推广,加强不同用途林木种质资源的开发利用。

双家沟泥石流特征及防治措施研究

泥石流具有爆发突然、来势迅猛、破坏性极大等特点,一旦发生将给工程建筑设施带来巨大威胁。双家沟为一条较为活跃的泥石流沟,通过现场踏勘、区域资料收集、室内试验,分析总结双家沟泥石流的发育特征,计算相关的动力学特征参数,包括泥石流的容重、流速、流量及一次泥石流总量,据此对泥石流的易发性进行评价。研究表明:双家沟属于轻度易发性泥石流沟,为中频稀性泥石流,现状处于泥石流的发展期,需采取相应的防治措施。

植被覆被条件下不稳定斜坡分布规律探究——以大渡河流域为例

近年,浅层滑坡、泥石流灾害发生在植被良好区的频率较大。一方面,植被对灾害的抑制或促进作用还有待进一步深入认知;另一方面,目前灾害风险源评估方法中较少考虑植被对斜坡稳定性的影响。为探究不同植被类型对浅层斜坡的稳定性影响,本文以大渡河流域作为研究区,通过对区域坡度、坡向及植被等数据提取和坡面划分,采用有限差分数值计算方法,对区域内划分的40000余个斜坡进行了稳定性计算,获取了该区域不同植被覆被条件下浅层斜坡的稳定性系数,探究在不同植被覆被条件下浅层不稳定斜坡的分布规律。结果表明随着坡度增加不同植被类型稳定斜坡数下降程度不一,总体上乔木林覆被斜坡稳定性较差,灌丛次之,草甸较好。进一步对区域内潜在浅层不稳定斜坡的植被类型和坡度进行统计分析,发现不同植被类型覆被条件下不稳定斜坡的坡度分布具有正态分布特征,基于建立的3种不同植被类型不稳定斜坡发育概率与坡度间的函数关系,确定出不同植被类型不稳定斜坡发育概率最高的坡度区间:乔木林为26.0°~37.0°,灌丛为28.0°~39.0°,草甸为31.0°~39.0°。本研究可以为流域尺度滑坡、泥石流等地质灾害的防治与规划提供依据,为良好植被区灾害风险评估中指标量化和权重确定提供数据支撑和思路参考。