Relationship between spatio-temporal evolution of soil pH and geological environment/surface cover in the eastern Nenjiang River Basin of Northeast China during the past 30 years

To illuminate the spatio-temporal variation characteristics and geochemical driving mechanism of soil pH in the Nenjiang River Basin,the National Multi-objective Regional Geochemical Survey data of topsoil,the Second National Soil Survey data and Normalized Difference Vegetation Index(NDVI)were analyzed.The areas of neutral and alkaline soil decreased by 21100 km^(2)and 30500 km^(2),respectively,while that of strongly alkaline,extremely alkaline,and strongly acidic soil increased by 19600 km^(2),18200 km^(2),and 15500 km^(2),respectively,during the past 30 years.NDVI decreased with the increase of soil pH when soil pH>8.0,and it was reversed when soil pH<5.0.There were significant differences in soil pH with various surface cover types,which showed an ascending order:Arbor<reed<maize<rice<high and medium-covered meadow<low-covered meadow<Puccinellia.The weathering products of minerals rich in K_(2)O,Na_(2)O,CaO,and MgO entered into the low plain and were enriched in different parts by water transportation and lake deposition,while Fe and Al remained in the low hilly areas,which was the geochemical driving mechanism.The results of this study will provide scientific basis for making scientific and rational decisions on soil acidification and salinization.

Using MaxEnt Model to Guide Marsh Conservation in the Nenjiang River Basin, Northeast China

Incorporating private and working lands into protected area networks could mitigate the isolation state of protected areas(PAs) and improve the efficiency of conservation.But how to select patches of land for conservation is still a troublesome issue.In this study, the MaxEnt model and irreplaceability index were applied to guide marsh conservation in the Nenjiang River Basin, Northeast China.According to the high accuracy of the MaxEnt model predictions(i.e., the average AUC value = 0.933), the Wuyuer River and Zhalong marshes in the downstream reaches of Wuyuer River are the optimal habitat for the Red-crowned crane and migratory waterfowls.There are 22 marsh patches selected by the patch irreplaceability index for conservation, of which 12 patches had been included in the current network of protected areas.The other 10 patches of marsh(amounting to 1096 km^2) far from human disturbances with high NDVI(up to 0.8) and close distance to water(less than 100 m), which are excluded from the existing network of PAs, should be implemented conservation easement programs to improve the protection efficiency of conservation.Specifically, the marshes at Taha, Tangchi, and Lamadian should be given priority for conservation and restoration to reintroduce migratory waterfowls, as this would lessen the current isolation state of the Zhalong National Nature Reserve.

Assessment of temporal and spatial variations in surface water quality using multivariate statistical techniques: A case study of Nenjiang River basin, China

Assessment of temporal and spatial variations in surface water quality is important to evaluate the health of a watershed and make necessary management decisions to control current and future pollution of receiving water bodies. In this work, surface water quality data for 12 physical and chemical parameters collected from 10 sampling sites in the Nenjiang River basin during the years(2012-2013) were analyzed. The results show that river water quality has significant temporal and spatial variations. Hierarchical cluster analysis(HCA) grouped 12 months into three periods(LF, MF and HF) and classified 10 monitoring sites into three regions(LP, MP and HP) based on the similarity of water quality characteristics. The principle component analysis(PCA)/factor analysis(FA) was used to recognize the factors or origins responsible for temporal and spatial water quality variations. Temporal and spatial PCA/FA revealed that the Nenjiang River water chemistry was strongly affected by rock/water interaction, hydrologic processes and anthropogenic activities. This work demonstrates that the application of HCA and PCA/FA has achieved meaningful classification based on temporal and spatial criteria.

Impact of land use/land cover changes on ecosystem services in the Nenjiang River Basin, Northeast China

Introduction:The Nenjiang River Basin is an important foodstuff base and eco-environmental fragile area in Northeast China.With the rapid rise in human population,human-induced changes in land use/land cover form an important component of regional environment and ecosystem service change.At the local and regional level,the ecosystem service concept can act as a decision support tool for a stakeholder to reach sustainable land use management.However,the prevailing ecosystem service evaluation would produce a biggish warp when it is applied to concrete area.So,it is essential to evaluate ecosystem service change according to the local actuality.Method:According to 1:250,000 land use/land cover maps of China and the adjusted equivalent value per unit area of ecosystem services in the Nenjiang River Basin,we evaluated the ecosystem service change of the river basin from 1980 to 2005.Results:The forest and wetland,which are mainly located in the upstream mountainous area of the Nenjiang River Basin,were the two valuable land cover types,accounting for more than three quarters of the total ecosystem service value of the river basin.As for individual ecosystem service,besides the food production,all of the ecosystem service values declined from 1980 to 2005.The total decline of 2.43 billion USD was mainly due to the cultivation of grassland(14.34%of the area in 1980)and wetland(4.62%of the area in 1980)in the downstream plain.Conclusions:Due to the increase in population and the concomitant requirement of grain,the inconsistency between decision-making at the macro-level,and the objective of agricultural production at the micro-level,cultivated land was increased through zealous reclamation of grassland,marginal woodland,and even fallow land.Tremendous land use/land cover changes had caused great damages to the ecological environment such as land degradation and ecosystem service recession.So,the policies of the Grain for Green and Construction of Ecological Province projects should be well-implemented to optimize land use/land cover.

THE FLOOD OF THE NENJIANG RIVER AND THE SONGHUA RIVER IN 1998 AND THE COMPREHENSIVE MANAGEMENT OF THE RIVER BASINS

In the summer of 1998, an exceptionally serious flood, with the characteristics of high water level, large volume of flow, long duration and serious losses caused by the disaster, occurred in the Nenjiang River basin and the Songhua River basin. Greater flood peak occurred three times in the trunk stream of the Nenjiang River for the floods occurred in its tributaries one after another. At Jiangqiao Hydrometric Station, the water level was 141.90 m and the rate of flow was 12?000 m 3/s. The flood is ranged to a catastrophic one, which occurs once in 50 years. Ranged to a catastrophic flood at Qiqihar Hydrometric Station that occurs once in 400 years, its water level, 0.89 m higher than the former all time highest, was 149.30?m and the corresponding rate of flow was 14?800?m 3/s. The water level that exceeded the all time highest lasted for 7 days. At Harbin Hydrometric Station, the water level, 0.59?m higher than the former all time highest, was 120.89?m and the corresponding rate of flow was 17?400?m 3/s. The water level that exceeded the all time highest lasted for 9 to 10 days. The flood here is ranged to a catastrophic one, which occurs once in 150 years. The flood of the Nenjiang River damaged 456×10 4?ha of crops and 115×10 4 rooms and the direct loss of economy exceeded 40 billion yuan(RMB). The main reasons of the flood are great rainfall, long flood season, unreasonable land use, regional ecological environment degradation and lack of water control projects. It is obvious that the following measures are greatly needed: the comprehensive management of the river basins; the formulation of development planning of the river basins, especially the water control projects; the development of agriculture based on ecological security.

Mountain Effect and Differences in Storm Floods between Northern and Southern Sources of the Songhua River Basin

In this study, the differences in annual rainstorm changes in the Second Songhua River Basin and the Nenjiang River basin and their causes were compared from the perspective of mountain effects. The following results were drawn: (1) Altitude effect is the primary factor leading to increased rainstorms in the southern source; (2) Slope effect primarily leads to differences of the weather systems in the two sources, and thus cause the difference of the rainstorms; (3) Slope effect is responsible for the greater fluctuation in the observed floods in the southern source. These landform differences eventually lead to the differences in the characteristics of floods in the southern and northern sources. Commensurability method was used to identify the period of rainstorms in the southern and northern sources. The results showed that although rainstorms do not appear at the same time in the two sources they are characteristic of a 10 years' period in both areas. These results can serve as hydrological references for flood control and long-term flood disaster predictions.

嫩江流域生态干旱影响因素及其时空演变格局

近几十年来,嫩江流域湿地大面积萎缩、土地盐碱化严重,干旱频发,严重威胁生态安全、水环境安全和社会经济可持续发展。为量化嫩江流域干旱对生态系统的影响,利用标准化生态缺水指数(SEWDI),结合旋转经验正交函数、累积和曲线和Pearson相关性分析法分析嫩江流域1980—2017年生态干旱的时空演变规律,并利用游程理论提取生态干旱特征。结果表明:(1)生态干旱与影响因子间的相关系数排序为相对湿度>归一化植被指数>径流>降水>气温,其中生态干旱和相对湿度相关系数最大且大于0.5,呈现显著相关性,其余因子的相关系数均小于0.5,呈现低度相关性;(2)从SEWDI变化曲线上看,1980—1999年干湿交替呈现出一定的周期性,生态干旱以轻旱和中旱为主,总体呈加剧趋势;2000—2017年极端干旱和极端湿润事件频发,生态干旱总体呈缓解趋势。从累积和曲线上看,1980—1995年为嫩江流域生态干湿状态的正常波动时期,1996—2009年为嫩江流域生态干旱期,2012—2017年为生态湿润期;(3)生态干旱的干旱历时和烈度显示流域西南部严重程度较大,长期干旱风险较高,而流域北部干旱强度较大,较易发生单次较为严重的短期干旱。

嫩江流域水文干旱归因分析及未来演变规律

在气候变化和人类活动的影响下,嫩江流域水旱灾害频繁发生。基于嫩江流域1980—2013年石灰窑、同盟、江桥和大赉水文站实测径流数据,构建流域分布式水文模型和多时间尺度下标准径流干旱指数(SRI),采用Budyko假设耦合水文模拟法对尼尔基水库建成前后流域径流变化和水文干旱特征归因分析,并基于第六次国际耦合模式比较计划(CMIP6)探究流域未来情景下水文干旱演变规律。结果表明:年尺度下,人类活动为径流演变的主导因素,影响贡献率高达80%,上游至下游水文干旱特征整体呈加剧趋势,且水库上游主要受到气候变化影响,下游主要受到人类活动影响;未来情景下,SRI序列波动性增大且呈现干湿交替特征,干旱历时呈增加趋势,流域未来干旱风险增大。

水循环与水资源合理配置模型(SWAM)Ⅱ:应用

为进一步检验SWAM功能,基于嫩江流域6个水文站的月径流系列、水库基本参数与入库径流、历年供用水量、水利工程分布情况等资料,构建了嫩江流域水循环与水资源合理配置模型,应用模型中的水循环模块,模拟分析了规划水平年2025年嫩江流域的水循环转化关系,在此基础上,计算了嫩江流域各地市可供水量,预测了规划水平年各行业的需水量,进行了水资源多目标优化配置分析,其中多目标模块设定3个目标(社会目标、经济目标、水量目标),应用NSGA-II求得非劣解集,选出嫩江流域2025年不同来水频率下的水资源合理配置方案,并将配置结果反馈给水循环模块。结果显示:(1)率定期(2010—2014年)6个水文站月径流模拟值与实测值的纳什效率系数均大于0.625,验证期(2015—2016年)6个水文站月径流模拟值与实测值的纳什效率系数均大于0.601,率定期与验证期的流量月过程线的拟合程度均较好。(2)嫩江流域2025年在P=50%的来水频率下,全流域的总降水量为1325.0亿m^(3),蒸散发量为886.0亿m^(3),下渗量为141.2亿m^(3),流域年末土壤水蓄变量为1.3亿m^(3),入境水量为135.0亿m^(3),出境水量为307.0亿m^(3),经济社会总取水量为131.5亿m^(3);其中,平原区地表水取水量为88.4亿m^(3),浅层地下水取水量为42.5亿m^(3),再生水取水量为0.6亿m^(3)。在P=90%的来水频率下,全流域的总降水量为1081.0亿m^(3),蒸散发量为953.3亿m^(3),流域年末土壤水蓄变量为-4.2亿m^(3);经济社会总取水量为138.9亿m^(3),地表水取水量为82.9亿m^(3),浅层地下水取水量为55.1亿m^(3),再生水取水量为0.9亿m^(3)。(3)在P=50%来水频率下,最优水资源配置方案对应的流域总需水量为134.3亿m^(3),总缺水量为2.8亿m^(3),缺水率为2.1%,经济损失量为1.5亿元,粮食减产量为51.0万t;在P=90%的来水频率下,最优水资源配置方案对应的流域总需水量为154.6亿m^(3),总缺水量为15.7亿m^(3),缺水率为10.2%,经济损失量为9.1亿元,粮食减产量为261.4万t。

数字孪生松辽流域建设与应用实践

结合松辽流域管理需求,梳理了现阶段流域水利信息化发展现状与问题,提出了数字孪生松辽流域建设目标与技术框架;聚焦流域防洪问题,选取重点防洪区域嫩江作为试点,提出了数字孪生流域建设实施路径,总结了试点建设应用情况,为数字孪生技术在水利行业的应用实践提供借鉴,为数字孪生松辽流域建设奠定基础。

嫩江流域多年降水特征分析

[目的]探究嫩江流域降水及季节性降水变化特征。[方法]选取该流域内10个气象站,基于1969—2010年逐日降水数据,计算年降水量及冬夏季降水量,采用Mann-Kendall趋势检验法分析流域降水变化趋势,采用Theil-Sen estimator来计算趋势幅度,并利用Mann-Kendall突变检测法确定流域降水量发生突变的关键节点,综合分析嫩江流域降水的时间变化特征。[结果]近42年来嫩江流域年降水量以4.7 mm/10 a的幅度不显著下降,夏季降水量下降幅度(10.1 mm/10 a)高于年降水量,冬季降水量则表现为显著上升趋势,变化幅度为1.3 mm/10 a。嫩江流域年降水量为373.1~507.8 mm,夏季降水量为231.7~309.4 mm,冬季降水量为3.6~11.4 mm,中上游的降水量高于下游,10个站点年降水量主要以下降趋势为主,夏季降水量均表现为下降趋势,除乾安站降水量不显著下降外,其他站点冬季降水量均表现为上升趋势。夏季降水变化与年降水表现为较高的相似性,两者的Mann-Kendall突变检验结果也在形态上非常相近,均出现3个阶段的趋势变化,且波峰相近;在20世纪70年代前后为第1阶段,表现为减少趋势;80—90年代为第2阶段,表现为增加趋势;21世纪初期为第3阶段,再次表现为下降趋势。在0.05显著性水平上,年、夏季降水量在20世纪70年代前后和21世纪初期存在多个突变点,降水减少阶段变化较不稳定,增加阶段无交点存在。冬季与年、夏季结果差异较大,表现为在1973—1978和1980—1986年降水量下降,其他时间段降水量上升;1998年为0.05显著性水平上的交点。[结论]嫩江流域多年降水特征以夏季降水量占年降水量比重大,且经历了减少—增加—减少趋势变化,最终表现为减少趋势。冬季降水量在1998年出现突变节点,该年之后冬季降水量显著增加。夏季降水是洪涝隐患之一,但多年来,不断增长的冬季降水变化也要给予关注。

嫩江流域近45年来径流演变规律研究

采用随机水文学方法对嫩江流域1956—2000年的年径流量序列演变特征进行分析。结果表明，嫩江流域径流的水文周期是32a，整体而言，45a径流序列不存在明显的趋势性。此外，对嫩江流域用水性消耗程度进行分析。结果表明，人类用水性消耗量对流域水循环整体影响程度为5％，但是在流域内部影响程度存在较大差异。洮儿河子流域影响因子达到16％，反映该地区人类取用水消耗量较大。从年际分析，整个流域在70年代的影响因子要高于其它年段，呈现出越是枯水年段人类用水影响程度越大的现象。

嫩江流域径流时空演化规律分析

以流域时空分布理论框架为基础,分析嫩江流域径流时空演化规律,并着重从地形地貌影响因素方面进行归因分析。采用1955—2003年49a的降水资料和1955—1973年19a的径流资料,通过对代表性水文站自上游至下游(空间上)径流、地表径流和地下径流的年内与年际(时间上)演变规律进行分析。结果表明:1)嫩江流域降水年内变化及年际变化过程基本一致,可以忽略降水时空分布对径流时空演化规律的影响。2)从径流年内演化规律上可以判定上下游水源组合的差异性:上游以地表径流为主,在春季来源于融雪,汛期来源于大气降水,枯水季节来源于地下水补给;下游全年以地下径流为主。3)由于坡度和水文地质条件作用,上游更容易产流,下游受下垫面调蓄作用更强,不易产流;因此,从径流年际演化规律上可以判定径流产量自上游至下游逐渐减小。

递归数字滤波法在嫩江流域地下径流分割中的应用

根据嫩江干流尼尔基水文站1955—1973年天然日径流资料,采用Eckhardt递归数字滤波算法进行地下径流分割计算.在径流分割过程中,对于滤波方程主要参数最大地下径流指数IGF,max的率定,本文首次提出了滑动最小值试算法.计算结果表明:嫩江流域尼尔基水文站地下径流指数IGF约为0.66,其中枯水期IGF约为0.88,丰水期IGF约为0.64.

嫩江流域沼泽湿地景观变化及其水文驱动因素分析

借助ArcGIS空间分析工具,以嫩江流域1978年、1990年、2000年和2008年4期遥感湿地分布图为基础,采用SWAT(Soil and Water Assessment Tool)水文模型将嫩江流域划分为43个子流域,并以沼泽湿地类型为例,将各个子流域内降水和径流信息与湿地退化遥感信息作对比筛选,对全流域以及湿地面积减少严重所在子流域作进一步分析。另外,利用两期土地利用类型数据生成嫩江流域土地利用转移矩阵。结果表明:1978—2008年间嫩江流域沼泽湿地退化严重,尤其以1990—2000年间最为显著。这与流域内降水、径流的变化密切相关,并受到土地利用类型转化以及水利工程建设等人类活动的影响。其中,沼泽湿地面积变化与流域径流系数变化在0.01水平上呈极显著正相关,pearson相关系数为0.90。气候变化和人类活动影响下对湿地水文过程以及水资源的变化,导致湿地日益萎缩,对流域内湿地生态系统平衡产生了负面影响。

耦合湿地模块的流域水文模型模拟效率评价

耦合湿地模块的流域水文模型是开展流域湿地变化的水文效应及其水文功能评估的有效工具,其模拟效率直接关系到模拟精度和应用价值。选取中国湿地主要分布区之一的嫩江流域,利用PHYSITEL/HYDROTEL模型平台,构建孤立湿地和河滨湿地模块并与流域水文模型耦合,并从拟合优度指数和模拟效率角度评价了耦合湿地模块的流域水文模型模拟效率。结果表明,耦合湿地模块的流域水文模型,拟合和验证期间模型的拟合度指数均有所提高,嫩江富拉尔基和大赉水文站控制流域的Nash-Sutcliffe系数和克林效率系数平均提高了3.08%和4.64%,均方根误差和相对偏差平均降低了12.72%和55.93%,且整个研究时段模拟结果的流量指数总体更接近于观测的径流数据。可见,耦合湿地模块的流域水文模型可提高水文过程模拟精度,更好地定量评估湿地水文功能,为流域水资源精准调控与湿地修复保护提供重要支撑。

嫩江流域径流与主要大气环流指标相关分析

本文选取影响嫩江径流变化的主要大气环流指标进行相关分析,以揭示大气环流指标对于径流空间和时程影响规律。分析结果表明:在空间分布上,嫩江流域干流及支流径流与大气环流主要指标相关性存在明显的空间分布特征,即上游断面径流与大气环流指标相关性较大,下游相关性较小。在时程演变上,嫩江流域径流与前1个月的大气环流指标相关性较大,与其他前期月份的相关性迅速减小,说明在做中长期径流预报时,大气环流前滞期可以选1个月,更较前的大气环流对当月径流影响不大。这些结论可以为中长期径流预报预报因子的选择和预报模型的建立提供基础参考。

基于水热耦合平衡理论的嫩江流域蒸散发估算

由于区域蒸散发时空变异性较大,难以采用点位监测方法来测定,因此,流域蒸散发估算是目前水文学领域的难点和重点问题。从水热耦合平衡理论入手,采用傅抱璞公式估算嫩江流域及典型汇水区的实际蒸散发。结果表明,傅抱璞公式的逐年蒸散发估算结果具有较高精度,且干燥度较大的汇水区的估算结果精度较高。然后,对嫩江流域蒸散发进行时空演化分析。结果表明:在1956—2000年,年实际蒸散发和潜在蒸散发均无趋势性变化;在2000—2013年,多年平均实际蒸散发与潜在蒸散发在空间上呈相反分布,整体上从上游至下游递减(递增)。最后,分析了下垫面参数w的分布规律,其表现为由上游至下游随植被覆盖率的减小而减小的特征。研究表明,傅抱璞公式为流域的蒸散发估算提供了可靠的方法,对于流域水资源预测和生态需水推求等具有十分重要的意义。

农村居民阅读的知与行——嫩江流域少数民族地区阅读情况调查

对于农村居民阅读少问题的研究,学界多偏重于农村阅读设施建设和服务模式等方面,关注农民自身的研究成果较少。笔者通过实地考察、现场问卷调查和家庭走访等方式,对嫩江流域51个民族村的阅读设施建设和居民的阅读情况进行调查,发现当前农村阅读中的突出问题是,认为阅读重要的人多而阅读的人少,争取阅读援助的人多而利用阅读设施的人少。这一现象误导了农村阅读设施反复投入和建设,并导致图书馆服务和研究进入误区。农村居民阅读少问题的根源在于农民阅读需求的复杂性。农村阅读中问题最多的是困难群体遭遇的各种障碍;其中难度最大的,是农民阅读需求的贫困与阅读行为的障碍。研究农村居民阅读认知和阅读行动的状况,对于图书馆抓住农村阅读服务关键,改善阅读服务途径和完善服务目标具有重要意义。表7。参考文献42。

松嫩辽流域夏季面雨量预测因子探讨

利用松花江、嫩江、辽河流域50余年45站降水资料和NCEP/NCAR再分析资料,分析了松嫩辽流域夏季面雨量的气候特征和影响夏季面雨量异常的前期因子,提出了一种利用前期11～12月北半球环流异常特征对该流域夏季旱涝趋势定性预测的方案,方案中定义了两个反映中高纬环流异常的指数,可以较好地分辨和预测松嫩辽流域面雨量异常.