Ecological water demand:the case of the slope systems in the East Liaohe River Basin

The ecological water demand (EWD) is the least water amount required to maintain the structure and the function of the special eco-system and the temporal scale of a study on the EWD must be a season's time. Based on GIS and RS with the source information of hydrological data of 46 hydrological gauges covering 52 years and the digital images of Landsat TM in 1986, 1996 and 2000, the landscape patterns, precipitation and runoff in the East Liaohe River Basin were analyzed. With the result of the above analysis, the spatial and temporal changes of the ecological water demand in the slope systems (EWDSS) of the East Liaohe River Basin (ELRB) were derived. Landscapes in the ELRB are dispersed and strongly disturbed by human actions. The hydrological regime in ELRB has distinct spatial variations. The average annual EWDSS in the ELRB is 504.72 mm (324.08-618.89 mm), and the average EWDSS in the growth season (from May to September) is 88.29% of the year's total EWDSS .The ultimate guaranteeing ratio of the EWDSS in ELRB is 90%. The scarce EWDSS area in the whole year and in the growth season are 60.47% and 74.01% of the entire basin respectively. The trend of scarce EWDSS area is most serious according to the quantity and area of scarce EWDSS regions.

Evaluation on Current Situation of the Water Ecology of the Main Rivers and Lakes in the Liaohe River Basin

In this paper,15 rivers and 10 lake reservoirs in the Liaohe River basin were taken as research objects. Based on six indexes: satisfaction situation of ecological water demand,standard-reaching rate of water quality in water function area,eutrophication index of lakes and reservoirs,longitudinal connectivity of rivers,reserve rate of important wetlands and status of important aquatic habitat,water ecological conditions of main rivers and lakes in the basin were evaluated. The results showed that the rivers with better ecology were mainly distributed in east mountainous area of Liaoning,such as the upper reaches of the Hunhe River and the Taizi River;the problems of water pollution,ecological water shortage and habitat shrinkage were widespread in the Liaohe River basin,and the situation of water ecological security in the Liaohe River basin still faced great pressure.

Impacts of future climate change(2030-2059)on debris flow hazard:A case study in the Upper Minjiang River basin,China

An increase in extreme precipitation events due to future climate change will have a decisive influence on the formation of debris flows in earthquake-stricken areas. This paper aimed to describe the possible impacts of future climate change on debris flow hazards in the Upper Minjiang River basin in Northwest Sichuan of China, which was severely affected by the 2008 Wenchuan earthquake. The study area was divided into 1285 catchments, which were used as the basic assessment units for debris flow hazards. Based on the current understanding of the causes of debris flows, a binary logistic regression model was used to screen key factors based on local geologic, geomorphologic, soil,vegetation, and meteorological and climatic conditions. We used the weighted summation method to obtain a composite index for debris flow hazards, based on two weight allocation methods: Relative Degree Analysis and rough set theory. Our results showed that the assessment model using the rough set theory resulted in better accuracy. According to the bias corrected and downscaled daily climate model data, future annual precipitation(2030-2059) in the study area are expected to decrease, with an increasing number of heavy rainfall events. Under future climate change, areas with a high-level of debris flow hazard will be even more dangerous, and 5.9% more of the study area was categorized as having a high-level hazard. Future climate change will cause an increase in debris flow hazard levels for 128 catchments, accounting for 10.5% of the total area. In the coming few decades, attention should be paid not only to traditional areas with high-level of debris flow hazards, but also to those areas with an increased hazard level to improve their resilience to debris flow disasters.

Research on Drainage Network Extraction in Liaohe Basin Based on SRTM DEM and ASTER GDEM

In this study,SRTM DEM data and ASTER GDEM data were used as the basic topographic data,and Arc Hydro Tools was utilized for extension module so as to study on extracting digital drainage network of watershed based on surface runoff model,as well as to compare the two extracted results.The result showed that through the introduction of drainage density parameter to determine the river drainage area threshold,the both extracted drainages showed the goodness-of-fit with the factual drainage network on 1∶250 000 scale topographic map,and the extracted digital river could be used in practical operation of the risk assessment model of mountain torrents disaster in Liaohe basin.

Temporal and Spatial Distribution Patterns of Grain Crops in the West Liaohe River Basin

Here,we quantitatively determine temporal and spatial distribution characteristics of main grain crops in the West Liaohe River basin,Inner Mongolia,China,from 2000 to 2010 based on MODIS remote sensing data and NDVI time series information for the years 2000,2005 and 2010.Phenological calendars and a decisionmaking tree extraction model were also used to obtain spatial distribution information of spring maize,spring wheat and soybean.We found that in 2010,the sown area of the main grain crops in the West Liaohe River basin was 11 965.08km2,of which,the sown area for spring maize accounted for 92.28%and was concentrated in the lower reaches of the region.Spring wheat accounted for 3.14% and was mainly in the middle reaches.Soybean accounted for 4.58% and was predominantly in the upper reaches.From 2000 to 2005,the sown area of these grain crops in the West Liaohe River basin grew by 29.77%,mainly in the lower reaches： spring maize grew by 38.99%,spring wheat by 39.04% and soybean by 21.27%.From 2005 to 2010,growth in the sown area of these crops was slow（5.18% growth） and mainly in the lower reaches of the basin.The sown area of spring maize increased,but decreased for both spring wheat and soybean.

Occurrence and bioaccumulation of polybrominated diphenyl ethers in sediments and paddy ecosystems of Liaohe River Basin, northeast China

Concentrations of 16 polybrominated diphenyl ether（PBDE） congeners were measured in river sediments, paddy soils and three species of paddy-field organisms（crab, loach and carp） collected from the Liaohe River Basin, northeastern China. The total contents of PBDEs（∑_（16）PBDEs） in sediments and paddy soils were in the ranges of 273.4–3246.3 pg/g dry weight（dw）, and 192.1–1783.8 pg/g dw, respectively. BDE 209 was the dominant congener both in sediments and paddy soils. The concentrations of ∑_（16）PBDEs in sediments were significantly higher than those in the adjacent paddy soils, indicating a potential transport of PBDEs from river to paddy ecosystems via river water irrigation. The biota–soil accumulation factor（BSAF） was calculated as the ratio between the lipid-normalized concentration in paddyfield organisms and the total organic carbon-normalized concentration in paddy soil. The average BSAF values of ∑15PBDEs followed the sequence of crab（3.6） 〉 loach（3.3） 〉 carp（2.1）. BDE 154 had the highest BSAF value, and a parabolic trend between BSAF values of individual PBDE congeners and their log KOWvalues was observed. In view of the fact that crab had the larger BSAF value and higher lipid content, the ecological risk and health risk for crab cultivation in paddy fields should be of particular concern.

Quantification of human and climate contributions to multi-dimensional hydrological alterations:A case study in the Upper Minjiang River,China

Dual factors of climate and human on the hydrological process are reflected not only in changes in the spatiotemporal distribution of water resource amounts but also in the various characteristics of river flow regimes. Isolating and quantifying their contributions to these hydrological alterations helps us to comprehensively understand the response mechanism and patterns of hydrological process to the two kinds of factors. Here we develop a general framework using hydrological model and 33 indicators to describe hydrological process and quantify the impact from climate and human. And we select the Upper Minjiang River(UMR) as a case to explore its feasibility. The results indicate that our approach successfully recognizes the characteristics of river flow regimes in different scenarios and quantitatively separates the climate and human contributions to multi-dimensional hydrological alterations. Among these indicators, 26 of 33 indicators decrease over the past half-century(1961–2012) in the UMR, with change rates ranging from 1.3% to 33.2%, and the human impacts are the dominant factor affecting hydrological processes, with an average relative contribution rate of 58.6%. Climate change causes an increase in most indicators, with an average relative contribution rate of 41.4%. Specifically, changes in precipitation and reservoir operation may play a considerable role in inducing these alterations. The findings in this study help us better understand the response mechanism of hydrological process under changing environment and is conducive to climate change adaptation, water resource planning and ecological construction.

辽河流域防洪现状及重难点问题解决思路

在客观全面评估辽河流域防洪工程体系现状基础上,深入分析流域防洪情势变化,重点剖析西辽河流域防洪工程布局亟须优化调整、辽河干流洪水外排能力仍显不足、绕阳河防洪工程体系不完善等流域防洪重难点问题,探究构建辽河流域防洪保安新格局的规划路径。

近53 a辽河流域旱涝灾害的时空特征

针对气候变化背景下辽河流域旱涝事件的频繁发生,以国家气象中心提供的地面降水日值数据集V3.0为基础数据,采用Z指数法表征旱涝事件,并应用集合经验模态分解法(EEMD)分析了辽河流域1968—2020年逐年、逐生长季的旱涝事件分布特征及其周期性规律,结果表明:(1)辽河流域近53 a中发生旱涝事件的灾害年份约占总时间序列的2/3以上,集中发生于上世纪80、90年代中后期及本世纪00年代.(2)近53 a中,重度干旱或洪涝事件均以流域东南部的河流下游及入海口区域最为严重,流域东南部的旱涝程度反差最为强烈.(3)对于辽河流域范围的旱涝事件来说,周期特征以短时高频振荡为主,年代际尺度的波动对于周期规律的贡献率相对较低.

闽江流域多时间尺度降雨—径流关系变化与成因

为进一步揭示闽江流域降雨—径流关系的时空变化规律,识别主要驱动因子,基于1960—2019年降雨和径流数据,应用TFPW—MK方法,按照年以及年内的汛期与非汛期、前汛期和后汛期、最大月和最小月等不同时间尺度,检测闽江上游三大支流、干流及全流域等空间尺度的降雨—径流演变趋势;结合Sen trend方法,从气候变化、土地利用和水库工程建设3方面,分析影响降雨—径流关系变化的成因。结果表明:1)闽江流域及各支流年降雨—径流均呈不显著上升,趋势变化一致;2)除支流建溪流域,闽江及其他支流非汛期降雨—径流上升趋势显著;汛期内部趋势变化分化明显,前汛期降雨—径流略减少,后汛期降雨—径流大部分显著增加;3)极端降雨—径流的变化趋势不一致,主要受大型水库工程建设的影响。基于多时间尺度的分析,更深入揭示闽江流域降水、径流的演变及气候变化与人类活动的影响,对区域水资源管理与水土保持具有重要参考价值。

基于MODIS-NDVI的岷江流域植被时空演变及地形分异研究

岷江是长江水系的重要分支之一,流经川西高原以及四川盆地地区。植被作为重要的生态指标之一,通过研究岷江流域的植被时空变化特征将有助于了解该流域的生态环境情况并为后续的生态治理提供参考依据。基于2003年~2021年岷江流域的MODIS-NDVI数据集以及DEM数据,借助于空间分析技术、Hurst指数、线性趋势分析、变异系数等方法多方面分析了岷江流域植被覆盖的时空演变特征以及地形因子对其变化趋势的影响性。结果表明:(1)研究时段内的NDVI均值介于0~0.9之间。其流域的NDVI值上中游偏高,下游偏低,岷江流域植被整体呈现波动上升的趋势,增长速率为2.4%/10a。(2)岷江流域植被覆盖呈增加趋势和减少趋势的面积分别占84.49%和15.51%。川西高原的河谷地区以及四川盆地的非城镇区域呈现显著增长趋势。呈减少趋势的主要分布在成都市向外扩张的新城区、眉山市和德阳市。(3)波动性较强的区域主要分布在川西高原的高海拔山地以及成都市,而低波动主要出现在川西高原的相对低海拔区域,植被较为稳定。(4)植被未来变化趋势呈现持续性减少的主要是成都市向外扩张的新城区。而呈现持续性增加的主要分布在四川盆地的非城镇地区以及川西高原的河谷地区。(5)海拔和坡度作为影响植被变化的主要因素,坡向与植被变化的相关性并未显示出明显的规律。

气候和土地利用变化情景下闽江流域水沙变化模拟

[目的]模拟未来土地利用和气候影响下的流域水沙变化有利于制定适合的流域管理计划。[方法]基于土地利用和气象数据,结合CMIP6气候模式数据、PLUS模型和SWAT模型,定量模拟2030年土地利用及不同气候情景下径流和泥沙的时空变化。[结果](1)SWAT模型在闽江流域月尺度模拟精度较好,其中径流模拟的R 2范围为0.80~0.95,NSE范围为0.75~0.91;泥沙模拟的R 2范围为0.75~0.98,NSE范围为0.64~0.94。(2)利用2020年土地利用数据对PLUS模型进行精度评估的Kappa系数为0.77,模拟2030年闽江流域建设用地和耕地将分别增加325.64,1157.51 km^(2)。(3)SSP2-4.5和SSP5-8.5情景下,2025-2035年平均降水量分别增加0.15%和2.18%,年平均气温分别增加0.23,0.62℃。(4)低碳情景和高碳情景下,仅土地利用变化导致年平均径流量相较于基准期分别增加0.08%和0.07%,年平均输沙量分别增加0.24%和减少0.05%;仅气候变化导致年平均径流量相较基准期分别减少4.76%和4.11%,年平均输沙量分别增加18.12%和0.13%;土地利用和气候综合影响导致年平均径流量相较于基准期分别减少4.57%和3.93%,年平均输沙量分别增加18.28%和0.33%。(5)未来气候和土地利用综合变化情景下,地表径流和产沙量较高且增幅较大的区域集中在以南平邵武市为中心的流域西北部和以三明将乐县为中心的流域西南部。[结论]研究结果为未来闽江流域的合理开发建设提供一定参考依据。

基于文献计量分析的近30年闽江流域生态环境的研究现状与发展趋势

利用CiteSpace文献计量分析软件,选取1992—2022年CNKI核心期刊数据库收录的1248篇有关闽江流域生态环境的研究文献进行梳理,通过文献的作者、机构、关键词等绘制知识图谱并进行可视化分析。结果表明:(1)闽江流域生态环境研究文献不断增多,并且发文量总体呈波动增长的态势。其研究过程整体上分为3个阶段:探索阶段(1992—2005年)、快速增长阶段(2006—2012年)和波动增长阶段(2013—2022年)。(2)研究团队合作密切,形成具有规模的科研机构,其中福建师范大学的相关地理研究所是研究闽江流域生态环境的主要机构。机构之间的合作以地缘联系为主,跨区域合作的机构较少。(3)研究内容涉及环境、生态、湿地、土壤等多个学科交叉融合,并不断深入和扩展;研究热点突现强度主要集中在闽江河口的“短叶茳芏”“芦苇”“多样性”“群落结构”等方向。该研究结果以期为今后闽江流域的可持续发展提供相应参考。

1962—2021年闽江流域干湿演变特征及其对ENSO事件的响应

基于1962—2021年闽江流域29个气象观测站的日降水量数据,运用标准化降水指数(standard precipitation index,SPI),Mann-Kendal趋势检验(M-K检验)以及Morlet小波分析等多种方法,深入分析不同时间尺度下闽江流域干湿演变特征,同时,结合海温异常指数(sea surface temperature anomaly,SSTA),进一步探究闽江流域干湿对厄尔尼诺-南方涛动(El Ni?o-Southern Oscillation,ENSO)事件的响应。结果表明:近60年来,闽江流域整体呈不显著湿润化趋势,夏季在20世纪90年代后显著湿润化,秋季在1995年后有干旱化倾向,冬季比其他季节更容易出现极端干湿事件;从空间上看,流域东南部湿润化趋势明显,具有春季流域中部干旱化,夏季北部以及东南部湿润化,秋季南部干旱化的态势;全流域各级湿润和干旱事件均呈增加趋势,湿润事件多出现在夏季,干旱事件多出现在秋、冬季;闽江流域在20~30 a的范围内存在干—湿—干的周期变化。ENSO对闽江流域干湿有显著影响,且具有一定的滞后性,暖、冷事件的影响分别在滞后1~4个月和3~5个月最显著。

西辽河流域夏家店下层文化房址结构的分形分式与分期

在史前考古中,房址作为一个可以长期保存的建筑,分为居住址、窑址、窖穴等。房址的研究对新石器时代人类生活环境、生存条件、社会发展程度的研究有重要意义。本文将针对西辽河流域夏家店下层文化居住址进行详细研究,以探寻在房屋建造与居住过程中房址结构的变化,并对其进行分形分式与分期。

Vegetation distribution pattern along altitudinal gradient in subtropical mountainous and hilly river basin, China

Knowledge of vegetation distribution patterns is very important. Their relationships with topography and climate were explored through a geographically weighted regression （GWR） framework in a subtropical mountainous and hilly region, Minjiang River Basin of Fujian in China. The HJ-1 satellite image acquired on December 9, 2010 was utilized and NDVI index was calculated representing the range of vegetation greenness. Proper analysis units were achieved through segregation based on small sub-basins and altitudinal bands. Results indicated that the GWR model was more powerful than ordinary linear least square （OLS） regression in interpreting vegetation-environmental relationship, indicated by higher adjusted R2 and lower Akaike information criterion values. On one side, the OLS analysis revealed dominant positive influence from parameters of elevation and slope on vegetation distribution. On the other side, GWR analysis indicated that spatially, the parameters of topography had a very complex relationship with the vegetation distribution, as results of the various combinations of environmental factors, vegetation composition and also anthropogenic impact. The influences of elevation and slope generally decreased, from strongly positive to nearly zero, with increasing altitude and slope. Specially, most rapid changes of coefficients between NDVI and elevation or slope were observed in relatively flat and low-lying areas. This paper confirmed that the non-stationary analysis through the framework of GWR could lead to a better understanding of vegetation distribution in subtropical mountainous and hilly region. It was hoped that the proposed scale selection method combined with GWR framework would provide some guidelines on dealing with both spatial （horizontal） and altitudinal （vertical） non-stationarity in the dataset, and it could easily be applied in characterizing vegetation distribution patterns in other mountainous and hilly river basins and related research.

乐山市岷江沙咀断面水环境形势研究

乐山市是长江上游重要的生态屏障和水源涵养地,岷江是乐山市最重要的水系之一,其干流水质稳定达标十分重要。岷江沙咀断面是乐山境内岷江干流上水质达标不稳定的断面。为探明岷江沙咀断面水环境形势,分析了2017—2022年六年中岷江沙咀断面水环境质量和流量的变化情况。结果表明,六年来岷江沙咀断面水质总体较好,水质达标率可达97.2%。高锰酸盐指数受五通桥区面源污染影响较大,氨氮与总磷浓度受流量影响较大。岷江流域长期存在水资源承载能力不足、资源性缺水严重的问题,同时岷江沙咀断面上游五通桥区工业源和农业源的氮磷废水排放问题较严重。后续建议结合航电枢纽开展生态用水调度研究,同时加强工业源和农业源污染物控制。

岷江流域生态脆弱性时空演变及影响因素分析

岷江流域位于四川盆地西部边缘过渡地带,是西南地区典型生态脆弱区之一,探索其生态环境脆弱性的时空演变及影响因素对维持四川省生态系统稳定性至关重要。利用“压力-状态-反应”(PSR)模型,收集多源数据,并利用熵值-Critic法评估权重,分析2012—2022年岷江流域的生态环境时空演变特征,采用地理探测器模型评估流域生态脆弱性的影响因素。结果表明,(1)岷江流域在研究时间段内整体脆弱性先升后降,重度、极度脆弱面积在中部先扩张后收缩,轻度脆弱面积自2017年后以成都市区为中心面积陡增,流域生态环境显著改善;且具有北部高-高聚集,中部、南部低-低聚集的空间分布特征。(2)在政策因素相对稳定的条件下,影响岷江流域生态脆弱性的主要因素是年均降水量和高程,且气候因素对生态脆弱性的影响程度逐步增强。研究成果可为岷江流域生态环境修复和“两山”建设提供理论依据。

基于趋势分析和Kendall算法的辽河水质分析

文章通过选取辽河干流6处典型断面,以COD和NH3-N作为评价指标,深入剖析辽河的水质污染状况及其变化趋势。通过应用Kendall算法以及趋势分析法,系统地分析了2020—2022年间辽河各监测断面水质的变化趋势与特征。结果表明:虽然各断面的COD和NH3-N浓度整体保持相对稳定,但部分断面仍呈现出不显著的上升趋势。该成果可为辽河水质治理提供一定参考。

闽江流域历史文化保护传承的空间格局探析——基于文化景观视角

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