Spatial matching and flow in supply and demand of water provision services: A case study in Xiangjiang River Basin

Global climate change and increased human consumption have aggravated the uneven spatiotemporal distribution of watershed water resources, affecting the water provision supply and demand state. However, this problem has often been ignored. The present study used the Xiangjiang River basin(XRB) as the study area, and the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST) model, demand quantification model,supply–demand ratio, and water flow formula were applied to explore the spatial heterogeneity, flow, and equilibrium between water supply and demand. The results demonstrated significant spatial heterogeneity in the upstream, midstream, and downstream regions.The areas of water shortage were mainly located the downstream of the Changsha–Zhuzhou–Xiangtan urban agglomeration, and the Hengyang basin was the most scarcity area. Affected by terrain gradients and human needs, water flow varied from-16.33 × 10^(8) m^(3) to 13.69 × 10^(8) m^(3)from the upstream to the downstream area, which provided a possibility to reduce spatial heterogeneity. In the future, measures such as strengthening water resource system control,sponge city construction, and dynamic monitoring technology should be taken to balance the supply and demand of water in different river sections of the basin. This study can provide references for regulating water resources allocation in different reaches of the basin.

An Evaluation of Artificial Fish Nest for Assessment Enhancement Effects of Fishery Resources of in Xiangjiang River

Artificial fish nests are set in Lukou section and Hengyang section of Xiangjiang River from March 20 to May 10, 2019. The structure of artificial fish nest is bamboo frame, with the size of 2.5 m × 5.0 m × 4 and a unit frame area of 60 m2. A total of 58,201 eggs were collected by 24 monitoring times, of which 30,441 were from Lukou and 27,760 from Hengyang. 3831 fish eggs identify 8 fish species using morphological or molecular biological methods. The results showed that the number of eggs peaked from the 8th day to the 24th day after the nest entered the water, and then decreased rapidly. There was significant negative correlation between egg number in per m2 fish nest and days of fish nest (P < 0.01). The economic benefits of artificial fish nests were RMB 11.81 million. The artificial fish nest can not only increase the population of fish, but also has significant economic benefits.

Heavy metal pollution of soils and vegetables in the midstream and downstream of the Xiangjiang River, Hunan Province

219 农业土壤和 48 件蔬菜样品的一个总数在湖南省 Xiangjiang 河(Hengyang 长沙节) 从中流并且下游地被收集。累积特征。

Spatial distribution and environmental characterization of sediment-associated metals from middle-downstream of Xiangjiang River,southern China

The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.

Analysis and prediction of reference evapotranspiration with climate change in Xiangjiang River Basin, China

Reference evapotranspiration(ET_0) is often used to estimate actual evapotranspiration in water balance studies. In this study, the present and future spatial distributions and temporal trends of ET_0 in the Xiangjiang River Basin(XJRB) in China were analyzed. ET_0 during the period from1961 to 2010 was calculated with historical meteorological data using the FAO Penman-Monteith(FAO P-M) method, while ET_0 during the period from 2011 to 2100 was downscaled from the Coupled Model Intercomparison Project Phase 5(CMIP5) outputs under two emission scenarios, representative concentration pathway 4.5 and representative concentration pathway 8.5(RCP45 and RCP85), using the statistical downscaling model(SDSM). The spatial distribution and temporal trend of ET_0 were interpreted with the inverse distance weighted(IDW)method and Mann-Kendall test method, respectively. Results show that:(1) the mean annual ET_0 of the XJRB is 1 006.3 mm during the period from 1961 to 2010, and the lowest and highest values are found in the northeast and northwest parts due to the high latitude and spatial distribution of climatic factors, respectively;(2) the SDSM performs well in simulating the present ET_0 and can be used to predict the future ET_0 in the XJRB; and(3) CMIP5 predicts upward trends in annual ET_0 under the RCP45 and RCP85 scenarios during the period from 2011 to 2100.Compared with the reference period(1961e1990), ET_0 increases by 9.8%, 12.6%, and 15.6% under the RCP45 scenario and 10.2%, 19.1%, and27.3% under the RCP85 scenario during the periods from 2011 to 2040, from 2041 to 2070, and from 2071 to 2100, respectively. The predicted increasing ET_0 under the RCP85 scenario is greater than that under the RCP45 scenario during the period from 2011 to 2100.

THE RESEARCH ON THE DISTRIBUTION AND FORMS OF HEAVY METALS IN THE XIANGJIANG RIVER SEDIMENTS

In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied.

Estimation of future water resources of Xiangjiang River Basin with VIC model under multiple climate scenarios

Variation trends of water resources in the Xiangjiang River Basin over the coming decades have been investigated using the variable infiltration capacity(VIC) model and 14 general circulation models'(GCMs') projections under the representative concentration pathway(RCP4.5) scenario. Results show that the Xiangjiang River Basin will probably experience temperature rises during the period from 2021 to2050, with precipitation decrease in the 2020 s and increase in the 2030 s. The VIC model performs well for monthly discharge simulations with better performance for hydrometric stations on the main stream of the Xiangjiang River than for tributary catchments. The simulated annual discharges are significantly correlated to the recorded annual discharges for all the eight selected target stations. The Xiangjiang River Basin may experience water shortages induced by climate change. Annual water resources of the Xiangjiang River Basin over the period from 2021 to 2050 are projected to decrease by 2.76% on average within the range from-7.81% to 7.40%. It is essential to consider the potential impact of climate change on water resources in future planning for sustainable utilization of water resources.

Assessment of heavy metals in sediment cores from Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China

Samples were collected from two core sediments(C1 and C2) of Xiangjiang River,Chang-Zhu-Tan region,Hunan Province,China.The heavy metal contents are relatively higher,especially for the surface or near the surface layers.The calculated anthropogenic factor values indicate that all the heavy metals except for Cr in the core samples are enriched,especially for Cd,with the maximum enriching coefficients of 119.44,and 84.67 in C1 and C2,respectively.The correlation of heavy metals with sulphur indicates that they are precipitated as metal sulphides.Correlation matrix shows significant association between heavy metals and mud.Factor analysis identifies that signified anthropogenic activities affect the region of Xiangjiang River.

The Prediction Model of Heavy Metal Pollution in the Xiangjiang River Based on Matlab

[Objective] The study aimed to establish a model to predict heavy metal pollution in the Xiangjiang River(from Zhuzhou to Changsha) on the basis of Matlab.[Method] According to the data of heavy metal content in the Xiangjiang River(from Zhuzhou to Changsha),we established a non-linear regression model based on Matlab to forecast the content of Cd,Pb,Cu,Zn,As and Cr in the Xiangjiang River.[Result] Verification showed that the prediction models had a high precision,and the spatial variation of the predicted heavy metal content was basically consistent with the actual conditions,which indicated that these models could forecast the spatial variation of heavy metal content in the Xiangjiang River(from Zhuzhou to Changsha) well.[Conclusion] The research could provide theoretical bases for controlling the heavy metal pollution in the Xiangjiang River.

The Impacts of Regional Rainfall and Upstream Effect on Runoff of Xiangjiang River of Guizhou

Based on monthly runoff data of Xiangjiang River of Guizhou from June 2013 to June 2015 and monthly runoff data of Yachi River of Guizhou from April 2014 to May 2015,using REOF and multiple linear regression analysis,the effects of regional rainfall and monthly runoff of upstream river on monthly runoff of Xiangjiang River were studied. Seasonal temporal-spatial change of monthly runoff of Xiangjiang River and Yachi River mainly had two kinds of modalites. The first modality was artificial influence mode,which was absolutely main component of seasonal change of monthly runoff in Xiangjiang River and Yachi River,and peak appeared during August-October. Here,component of Yachi River was far larger than that of Xiangjiang River,and artificial control ability of monthly runoff in Xiangjiang River was far larger than Yachi River. The second modality was natural influence mode,and peak appeared in July. Xiangjiang River and Yachi River had similar natural influence component,and the component was only tiny part of seasonal change of monthly runoff in Xiangjiang River and Yachi River. Water gathering change of Xiangjiang River headstream showed by monthly runoff of Yachi River and the first mode of regional rainfall were main influence factors of monthly runoff of Xiangjiang River. Monthly runoff of Xiangjiang River,monthly runoff of Yachi River and the first mode of regional rainfall all had the same-phase seasonal change.

Research on the ecological compensation standard of the basin pollution control project based on evolutionary game theory and by taking Xiangjiang River as a case

Ecological compensation is a new resource and environment management model.As one of the main areas for implementing ecological compensation policies,basin ecological compensation has become an important measure for encouraging basin pollution control projects and improving the quality of regional economic development.By applying the basic game analysis of evolutionary game theory and building an evolutionary game model with a“reward-punishment”mechanism,this paper compares the interest-related decision-making behaviors of the upstream and downstream stakeholders of basin ecological compensation.By using data on the water quality of Xiangjiang River Basin,this paper calculates the rewards and penalties in different intervals by building a parametric regression mathematical model and employing the local linear regression method.Results show that a decline in water quality should be fined RMB 925500 yuan,an improvement in water quality should be awarded RMB 1227800 yuan,and a deteriorating water quality should be severely fined RMB 5087600 yuan.

Characteristics of the phytoplankton community and bioaccumulation of heavy metals during algal blooms in Xiangjiang River (Hunan,China)

The frequency of algal blooms has increased in the mid and downstream reaches of the Xiangjiang River (Hunan,China),one of the most heavily polluted rivers in China.We identified the bloom-forming species in a bloom that occurred mid-late September 2010.In addition,we determined the extent of metal bioaccumulation in the algae and measured the toxicity of the algae using a mouse bioassay.Water samples were collected at upstream (Yongzhou),midstream (Hengyang),and downstream (Zhuzhou,Xiangtan,and Changsha) sites.The dominant species was Aulacoseira granulata,formerly known as Melosira granulata.The heaviest bloom occurred at Xiangtan and Changsha,where the number of A.granulata peaked at 1.3×10 5 filaments L 1 and chlorophyll a at 0.04 mg L 1.Concentrations of Al,Fe,and Mn were 4.4 10 3,768.4,and 138.7 mg kg 1 dry weight in the phytoplankton.The bioaccumulation factor was 4.0×10 5,7.7×10 5,and 3.2×10 3,respectively.The heavy metal Pb had the greatest tendency to bioaccumulate among the highly toxic heavy metals,with a concentration of 19.2 mg kg 1 dry weight and bioaccumulation factor of 9.6×10 3.The mouse bioassay suggested the bloom was toxic.The LD 50 was 384 mg kg 1 and all surviving mice lost weight during the first 72 h after exposure.Our results demonstrate that blooms of A.granulata in rivers contaminated with heavy metals pose a threat to freshwater ecosystems and human health.Thus,measures should be taken to control eutrophication and heavy metal pollution in such rivers.

基于四维度模型的湖南省湘江流域洪涝灾害风险评估

当前极端气候事件频发,降水频次与强度剧增,致使区域洪涝风险提高。为了降低区域洪涝风险,从致灾因子危险性、孕灾环境敏感性、承灾体脆弱性和防灾减灾能力四维度分析洪涝灾害风险的形成机理,基于11项指标,综合运用ArcGIS地理信息软件与熵权法等数理统计方法客观赋权,对湖南省湘江流域的洪涝风险进行综合性评估,最终制作出区县尺度的洪涝风险分布图。结果表明:湘江流域中西部致灾因子危险性低,中游地区孕灾环境敏感性高;环长株潭地区与衡阳市的承灾体脆弱性较高,但前者凭借良好的经济基础,其防灾减灾能力相对较强;湘江流域洪涝风险分布从东北向西南呈增强趋势,高洪涝风险区位于长沙市、益阳市、衡阳市及永州市南部,不同地区洪涝风险的主导因子不同。研究结果较好地反映了多因子作用下地区洪涝风险的差异,可为区域防洪减灾提供支撑。

湘江湘潭段底泥中重金属污染分析

为了解湘江湘潭段表层沉积物的重金属污染情况,采集湘江湘潭市出入境断面(左右两侧)4个点位的表层沉积物,检测其7种重金属(Ni、Cu、Zn、As、Cd、Pb、Hg)的含量,采用行业内3种方法对沉积物中重金属的污染程度和潜在生态风险进行评价。研究表明,该区域底泥中重金属Cd的污染风险极高,同时Hg、As、Pb存在较大的污染风险。

考虑水系演变的湘江流域洪水风险四维评价体系构建

为刻画水系演变对洪水风险的影响,该研究区别于传统洪水风险评价方式,着重考虑水系演变的综合定量化研究,以湘江流域为例,构建基于水系演变的洪水风险评价体系,运用有别于主观赋值、具有一定客观性的熵权法,从致灾因子危险性、孕灾环境敏感性、承灾体脆弱性和防洪减灾能力4个维度开展1995-2015年洪水风险评价体系验证研究。研究结果表明:(1)1995-2015年,研究区水系大体呈衰减趋势且各市域之间水系变化差异大,其中河网密度和支流发育系数衰减率最高,分别达30.96%、34.01%,河道趋于主干化,单一化;(2)基于水系演变的洪水风险评价表明,期内,区内洪水风险程度逐渐提高,高风险地区发生在上游的永州市南部、郴州市西部、中游的衡阳市以及下游长沙市辖区;(3)定量化水系演变的流域洪水风险四维评价体系合理可行,且能更科学和细腻地反映城镇化背景下水系演变对洪水风险的影响,为流域农业生产和区域防洪减灾提供科学支撑。

考虑地表-土壤-作物水分联合亏缺的综合旱情指数研究

区域干旱发生发展受地表水、土壤水、作物水等多种缺水过程的共同影响,以往基于单一缺水过程构建的干旱指数难以反映实际旱情,综合考虑多种缺水过程构建综合旱情指数,对有效开展区域旱情监测具有重要的意义。基于水文作物耦合模型(VIC-EPIC)模拟数据,通过线性加权集成标准化径流指数(SRI)、土壤含水量距平指数(SMAPI)和作物缺水指数(CWDI),构建了反映地表土壤作物水分联合亏缺的综合旱情指数(CDSI),并采用1981—2020年数据在湘江流域开展了应用研究。结果表明,基于CDSI提取的旱情特征序列与流域内35个县1990—2007年受旱率相关性在0.4~0.8之间,82.9%通过5%显著性水平检验,与反映单一水分亏缺的SRI、SMAPI和CWDI相比,相关性整体上有较大提升。CDSI能够较好地反映区域实际旱情发生发展,可为大范围旱情准确识别和评估提供有效支撑。

基于Copula函数的湘江流域气象干旱向水文干旱传播特性

水文干旱的发生往往与气象干旱的发生密切相关,因此揭示两者间的响应关系对干旱预警及水资源管理具有极其重要意义。该研究以湘江流域为研究对象,采用标准化降水指数(standard precipitation index,SPI)和标准化径流指数(standard runoff index,SRI)分别表征气象干旱和水文干旱,采用皮尔逊相关系数确定干旱响应时间,并结合游程理论识别、融合和剔除干旱事件,分析湘江流域上、中、下游不同季节干旱的趋势性及周期性,最后建立基于Copula函数耦合贝叶斯网络模型的气象-水文干旱特征响应概率曲线。结果表明:湘江流域气象干旱到水文干旱的传播时间为2个月,阈值组合[0.5、0、-0.5]相较于组合[0、-0.3、-0.5]识别得到的干旱事件更优;下游发生水文干旱的情况最为严重,中游气象干旱最为严重,整体上水文干旱发生历时和烈度的最大值均大于气象干旱;流域整体有湿润化趋势,但是在夏季和秋季,存在干旱化的趋势;干湿变化存在几个较为明显的震荡周期,分别为3~5、6~10和18~21 a;对于联合分布函数,除了上游和下游气象-水文干旱烈度的最优联合分布为Gumbel Copula函数,其余干旱特征变量的最优联合分布均为Frank Copula函数;水文干旱历时、烈度的响应概率随气象干旱特征变量的增加而增加,但当气象干旱历时超出特定阈值时,水文干旱历时对其响应概率将趋于稳定,即当气象干旱历时超过特定阈值后,将不会进一步延长水文干旱的发生时长。该研究对深入了解湘江流域的干旱机理以及指导该地区防旱抗旱工作均具有重大意义。

基于重心模型的湘江流域水系与城镇化时空格局演变分析

针对城镇化导致水系及其水域空间被挤占、压缩甚至吞噬的现实问题,本研究采用1995、2005和2015年3期经Google Map校准后的水系与1995—2015年城镇建成区面积数据,运用空间计量模型和重心模型研究湘江流域1995—2015年水系演变与城镇化的时空特征,分析城镇建成区面积对水系变化的影响。研究结果得出:1)湘江流域水系总体呈衰减趋势,河流趋向主干化。各水系指标均产生空间集聚,与周围邻近地区存在相似性。但水系指标的空间集聚格局演变差异显著,河网密度(Dr)、河流弯曲度(Sr)、干流面积长度比(Rm)空间格局稳定,水面率(Wp)、河流发育系数(Kw)较不稳定。高值区集中在流域中下游,低值区则集中在株洲和永州。2)Dr、Kw、Sr、Wp与城镇化重心迁移方向相背离,Rm与城镇化重心迁移方向具有统一性,城镇化在水系演变过程中主要起负向影响。研究结果有助于为城市规划与水系保护提供参考。

传统聚落景观形态基因图谱研究——以湘江流域为例

文化景观是地理学研究的重要对象之一,而聚落为文化景观的重要构成。本文在文化景观基因内涵进行剖析的基础上,结合传统聚落的形态构成及感知结构,从环境、布局、边界、标志物、道路以及住宅6个方面来解析传统聚落的景观形态基因。以湘江流域为研究区域,通过对上中下游案例聚落形态基因的提取、转译与比对,形成文化景观形态基因图谱及编码序列图谱。在对编码序列图谱的比较分析中,得出如下结果:①相同景观形态基因。流域内传统聚落多依山而建,村前开塘,河流或溪涧环绕,多祠庙,村内常见桥梁、门楼、水井及古树,民居建筑基本以中轴对称、围合及天井为基本规则;②差异景观形态基因。中上游多为集聚形态,有较为清晰的水体边界,村内常见单栋的书房或书院;上游和下游多使用围墙围合,且民居易纵向延伸,形成多进住宅;在独特性上,上游聚落前多有案山作为屏障,聚落布局顺应山势呈“弧形”拓展,道路网络也多变体,多筑有风水阁塔,以求地方文武兴盛;中游多方正布局,主体路网也呈“网格”状,多设商铺街道;下游聚落离散分布,干枝状连接各处住宅,多南方大屋,布置庭院,两侧布置横屋。最后通过两张图谱呈现了湘江流域内传统聚落文化景观多位形态基因的空间分布规律。

水库群消落期多目标智能优化调度研究

本文考虑了河道天然流量模式调度需求,以发电量、供水满足度最大和河道流量偏差函数值最小为目标,建立了水库群消落期多目标优化调度模型,采用非支配排序遗传算法求解,以湘江流域东江-双牌-涔天河水库群为研究对象,进行了实例分析。研究结果表明:相比常规方案,在丰、平、枯水年情景下,发电量最大方案分别能提高1571万kW·h(11.2%)、1167万kW·h(10.9%)和811万kW·h(10.0%)的发电量;生态效益最好的方案,能减小1.56(61.2%)、0.33(6.3%)和0.89(13.6%)的河道流量偏差函数值;供水满足度最大的方案能提高2.1%、2.6%和3.4%的供水效益。构建的水库群消落期多目标优化调度模型可为长江流域水库群消落调度提供理论参考。