Method for calculating non-point source pollution distribution in plain rivers

The land area in a river network is divided into certain-scale square cells for the sake of precision, and, based on the physical mechanisms of rainfall-runoff processes and runoff pollution, the non-point source pollution from cells is estimated using the export coefficients of different land use types. The non-point source pollution from a land cell should all go into the closest fiver reach, so it is distributed according to the terrain of the plain river network area and the positions of land cells and river network reaches. A relationship between a single land cell and its pollution-receiving reach can be determined using this system. In view of the above, a spatial distribution model of the rainfall runoff and non-point source pollution in reaches of a plain river network area was established. This model can provide technological support for further research on the dynamic effects of non-point source pollution on water quality.

Late Quaternary diatom and sea level changes in estuarine plain of the Jiulong River

Four units and twenty-four zones of diatom have been discerned in the Borehole ZK5 in the estuarine plain of the Jiulong River, Fujian Province. Comprehensive analysis of these, together with microbiological assemblages and age determinations in some other boreholes, shows that during the Late Wurm Glacial, sea level of the study area rose and fell frequently, but had principally been in the environments of estuary-bay. This mainly resulted from the tectonic subouction. In this period 3 low sea levels occurred. at 18, 16 and 12 kaBP respectively. During Holocene, sea weter intruded massively and the sea level over the transgnaion maximum had been 5-10 m higher than that of the present.

Analysis on hydrochemical characteristics of groundwater in strongly exploited area in Hutuo River Plain

The Hutuo River alluvial-proluvial fan is located in North China Plain, and groundwater is the main source of water supply for agriculture and domestic water. Shijiazhuang depression funnels due to the long-term excessive exploitation are the bottleneck of the regional economic development. Analyzing the chemical characteristics of groundwater under the condition of strong human activities, can provide a scientific basis for further study of strong groundwater mining area environmental change. 143 groups of shallow groundwater samples are collected during the period of 2007-2008. In this paper, the hydrochemical characteristics of groundwater in the Hutuo River Plain area are analyzed systematically, using hydrogeochemical theory, combined with statistical methods and hydrochemical methods. Results are shown as follows: HCO_3^- and Ca^(2+) are major anion and cation. The variation coefficients of K^+, Ca^(2+), Mg^(2+) and HCO_3^- between 0.25 and 0.52, which means small and stable relatively. The variation coefficient of are Na^+, NO_3^-, Cl-, SO2-4 were large(0.89-1.01). They are sensitive and vulnerable to environmental change affect. Due to the impact of human activities, from the top to the edge of the alluvial-proluvial fan, the hydrochemical types of groundwater change from single to multiple, followed by HCO_3^-Ca·Mg, HCO_3·SO_4-Ca·Mg, HCO_3·SO_4·Cl-Ca·Mg, HCO_3·Cl-Ca·Mg and other types.

Assessment of shallow groundwater vulnerability in Dahei River Plain based on AHP and DRASTIC

Based on the special hydrogeological conditions of the Dahei River Plain in the Inner Mongolia area, assessment of shallow groundwater vulnerability is conducted based on DRASTIC model. Each evaluation indicator weight is determined by using analytic hierarchy process(AHP). The most important indicators are lithology in soil media and vadose zone. Assessment model of shallow groundwater vulnerability of the Dahei River plain is constructed. Distribution map of vulnerability index in this area is made with the spatial analysis function of ARCGIS. The results show that the particularly sensitive area is the piedmont of the Daqing Mountain, where the upstream place of the groundwater and the south-central place of the plain has the lowest vulnerability. The assessment results are more in accordance with the actual vulnerability conditions of this area by using analytic hierarchy process, and is helpful for groundwater protection.

Reconstruction of Sub-Decadal Winter Half-Year Temperature during 1651-2010 for the North China Plain Using Records of Frost Date

We extracted 374 pieces of records of frost date from historical documents. Using these records, we reconstructed winter half-year (October to next April) temperature series, with a resolution of 5-year, for the North China Plain during 1651-2010. The results show that the temperature changes in the North China Plain were divided into four phases. With the reference period of 1951-1980, two cold phases, 1651-1700 and 1781-1900, have cold anomaly of 0.83°C and 0.60°C respectively. However, between the two cold phases, 1701-1780 was a relative warm phase with the cold anomaly of 0.36°C referring to the mean of 1951-1980. After the 1900, the climate came into a warm phase. The mean temperature of 1901-2010 was 0.11°C higher than the mean of 1951-1980. During 1651-2010, the 1996-2000 is the warmest 5-year with the warm anomaly of 1.25°C than that of the reference period of 1951-1980.

基于AHP-熵权法的鄞西平原河网水环境改善效果综合评价

随着城市化的发展,河流间原有的联系被打断,水动力条件变差,继而引发水质污染、水生态功能衰退等问题。以鄞西平原为例,提出一种基于层次分析-熵权法的水环境改善效果评估方法,在水动力、水质参数的基础上,综合考虑经济效益和感官参数,全面评估水环境改善方案的效果。量化比选研究区提升效果,最终确定方案3为研究区改善效果最优方案。研究表明,基于层次分析法和熵权法的综合评价方法相较于传统仅考虑水动力、水质或其他单一因素的评价方法,能够克服定性数据和主观赋权对评价结果的影响,更加全面地评价不同连通方案的提升效果,实现了方案综合评价与优选。

Assessing Biogeomorphological State of the Teesta River Flood Plain: A Study on Gangachara Upazila, Rangpur, Bangladesh

Teesta river flood plain is one of the most significant landscapes in Bangladesh. The main theme of this research was to assess the present biogeomorphological state (biomass, herbaceous vegetation species, density of all vegetation species, flood plain extension mapping) of Teesta river flood plain under Gangachara upazila. The research work was conducted based on the objectives to prepare a map of Teesta river flood plain extension area, to estimate herbaceous vegetation (biomass, species types), and to find out the vegetation density to assess the present biogeomorphological state of study area. To present the flood plain area of Teesta river in the Gangachara upazila, base map has been used;herbaceous vegetation samples have been collected through quadrat method to estimate biomass (both in dry and before dry condition) using digital weight machine;vegetation density has been shown through NDVI of satellite image (Landsat-8) using red and NIR band in ArcGIS 10.1 software. From the results of this research, river flood plain area is found 68.5 sq. km;total 31 types of herbaceous species have been identified where Pouzolzia indica is the most dominated species covering 11.59% of the total area;maximum DNs value of NDVI is found +0.475242 which represents the highest vegetation density covering an area of 78 sq. km of the total area. The research may assist for the further study of river flood plain biogeomorphology throughout the country as well as in the world.

Geomorphological Evolution and Fluvial System Development during the Holocene: The Case of Vouraikos River Evolution in Kalavrita Plain, Northern Peloponnese, Greece

Fluvial geomorphology is affected by physical conditions which allow its adaptation due to high dynamics and environmental influences. Fluvial morphological changes are manifested as a result of tendency of the river system to maintain its physical balance. Our study area is the upper and middle flow part of Vouraikos river and surrounding area, near the NW border of Chelmos mountain in Northern Peloponnese, near the town of Kalavrita, at an altitude of 800 m. The area is part of the Skepasto basin, constituting of a graben with a general E-W direction that was developed NW of Kalavrita. The area comprises of Mesozoic, Upper Triassic-Jurassic limestone and dolomite of the Tripolitsa unit External Hellenides and Plio-Pleistocene fluvio-lacustrine sequences, while its tectonic structure is characterized mainly by normal faults. The geomorphological landscape is characterized by alluvial deposits and important geomorphological features including fluvial terraces, alluvial fans, fluvial scarps and their main rill washes. This area has been a place of major human activity as shown by the findings of many uncovered artifacts and a settlement. Through a paleographic reconstruction, detailed field investigations, in combination with the compilation of geomorphological maps using GIS software and archaeological evidence found in the area, we attempted to reconstruct the fluvial evolution of Vouraikos river and identify the major geomorphological factors that led to, and influenced it. Finally, the link between cultural activities and sedimentary processes is also studied. The recorded environmental variations had a great impact on the geomorphological shaping and instability of Kalavrita plain and Vouraikos river and are being reflected on the buried settlement. Sediment fluxes were high enough to form strath terraces, while local tectonics aided in the strath and fill terrace creation. Smaller and younger strath terraces, formed during increased sediment supply periods, when the valley was at a higher level.

Downstream Decreasing Channel Capacity of a Monsoon-dominated Bengal Basin River: A Case Study of Dwarkeswar River, Eastern India

Downstream changes in channel morphology and flow over the ephemeral Dwarkeswar River in the western part of the Bengal Basin, eastren India were investigated. The river stretches from the Proterozoic Granite Gneiss Complex to the recent Holocene alluvium, forming three distinctive geomorphological regions across the river basin: the pediplane and upper and lower alluvial areas. Sixty cross-sections from throughout the main trunk stream were surveyed and the bankfull width, depth, cross-sectional area, and maximum depth were measured. Sediment samples from each location were studied and the flow velocity, stream power, Manning’s roughness coefficient, and shear stress were estimated. The results show that the bankfull channel cross-section area, width, width-to-depth ratio, and channel capacity increased between the beginning and middle of the river. Thereafter, the size of the river started to decrease in the lower alluvial area. This was characterized by gentle gradients, cohesive bank materials with grass cover, and channel switching. Within the lower part of the river, the channel capacity was observed to diminish as the drainage area increased. This increased the bankfull flow frequency and accelerated large floodwater losses in the floodplain via overbank flows and floodways.

Application of River Network Hydrodynamic Model in Determining Water Distribution Scale of Haishu Plain

The water distribution network is an important part of the plain water environment improvement system. To make efficient use of the regional water diversion source, scientifically distribute the water diversion flow and improve the water environment carrying capacity of Haishu Plain, the river network hydrodynamic model is used in this paper to simulate the water intake location, reasonable water quantity and influence range of water transfer in Haishu Plain. The simulation results have high accuracy, which can provide a scientific basis for the scale, water transfer mechanism and project layout of water transfer construction in Haishu Plain and show a strong reference value for the study of water diversion and distribution scheme of coastal plain river network.

Study on Spatial Variability of Soil Infiltration Coefficient in the Plain of the Yili River Valley in Xinjiang

22 typical test points and 8 profiles were selected and arranged in the plain of Yili River Valley based on lithological distribution and sedimentary characteristics to study spatial variability of soil infiltration coefficient. The results show that the infiltration coefficient of different geo-morphic units is as follows: the desert area > the pre-mountain alluvial-proluvial plain > river terrace,which is mainly related to the lithology of aeration zone,buried depth of groundwater and underlying surface. For the infiltration coefficient of different aeration zone mediums,the results are consistent with the changing law. The partition of plain of the Yili River Valley is based on geo-morphic units,infiltration coefficient and the lithology of aeration zone. The maximum infiltration coefficient is concentrated in the desert area,and there is zonal distribution of infiltration coefficient in plane.

16-23S rRNA Spacer Region Polymorphism in Gangetic River Water Isolates of Salmonella

Salmonella is one of the major pathogenic bacteria present in contaminated water. 16-23S rRNA spacer region has been reported to be polymorphic at serovar level in Salmonella. Salmonella isolates obtained from Ganges river water were studied for 16-23S rRNA spacer region polymorphism. Thirty three isolates belonging to eight serovars (S. Typhimurium, S. Abuja, S. Pantypridd, S. Lagos, S. Chinkual, S. Zwickau, S. Goldenberg and S. Oritamerin) were studied for the polymorphism. Out of 33 isolates, 15 different profiles were observed no serovar specific profile. Our findings indicate that 16-23S rRNA spacer region is not specific at serovar level, but can be used for differentiation of different Salmonella isolates.

基于二层规划的玛纳斯河灌区山区-平原水库群联合调度

在水资源总量约束情况下,为缓解玛纳斯河灌区水资源供需矛盾,充分发挥流域内水库群的节水潜力,利用二层规划模型对山区-平原水库群进行联合优化调度.上层优化目标为水库群联调过程中的蒸发渗漏损失最小,模型对平原水库的引水规则和山区水库的调水规则进行优化,增加山区水库的蓄水机会;下层优化目标为灌区缺水指数最小,通过对各水库供水规则的优化,提高各子灌区的供水保证率.结果显示:山区-平原水库群联合调度减少了流域水库群的水量损失.采用优化引调水规则后,水库群多年平均蒸发渗漏损失水量可减少0.22×108m3,与现状水库群运行调度相比减少12.09%;山区-平原水库群联合调度提高了灌区供水保证率.优化供水规则的实行,在现状年和规划年水资源总量控制模拟中,各子灌区灌溉保证率分别提高了6.83%,7.37%,13.00%和17.02%,13.49%,12.97%.利用山区水库和平原水库的蒸发渗漏差异进行水库群联合调度可以达到发挥研究区域水库群节水效益的目的,基于二层规划的玛纳斯河灌区山区-平原水库群联合调度对发挥该研究区域水库群节水效益和提高水资源利用效率具有正向作用.

A PRELIMINARY STUDY OF THE YELLOW RIVER'S PALEOCHANNELS IN NORTH SHANDONG PLAIN

According to buried depth, the Yellow Rver's Paleochannels can be divided into ground Paleochannels (buried depth 0-8m) and shallowburied Paleochannels theried depth 8-50m). Each of them can be roughly divided into three major Paleochannel belts, stretching Parallel with each other from SW to NE. Sedimentary layers of the paleochannels were mainly made up by sand levee of meanders or natural leavee deposits, and the flooding sedments were found bebeen the layers. The paleochannels in North Shadong Plain were formed in three stags; stage I (buried depth 50-15m) in later period of late Pleistocene-early period of Holocene, stag II (20-8m) in earlymiddle period of HOlocene; and stag III (8-0m) in midddle-late period of Holocene.

基于PSO-LSTM模型的平原河网汛期水位预测

基于水位、流量、降水量长序列数据资料,构建了采用粒子群优化(PSO)算法进行超参数寻优的长短期记忆(LSTM)神经网络模型(PSO-LSTM模型),对位于江南运河苏州吴江段平原河网中心的平望站的汛期水位进行了预见期为1~3 d的短期预报,并与基于PSO算法的支持向量机(SVM)、随机森林(RF)、卷积神经网络(CNN)以及门控循环单元(GRU)模型的水位预测结果进行了对比,同时探究了水利工程对水位预报精度的影响。结果表明:对于预见期为1~3 d的短期预报,PSO-LSTM模型具有较高的预测精度,但随着预见期的增长,预测精度逐渐降低;相较于PSO-SVM、PSO-RF、PSO-CNN和PSO-GRU模型,PSO-LSTM模型的平均绝对百分比误差更低,预测效果更好;PSO-LSTM模型能够较有效地进行汛期平原河网的水位预测,且加入水利工程等人工调控影响因素能够提升水位预测效果。

船行波对H-ADCP影响分析研究

作为当今世界上最先进的测流仪器,水平式声学多普勒流速剖面仪(Horizontal Acoustic Doppler Current Profiler,H-ADCP)因其精度高、速度快等突出优势在河流中的应用越来越广泛,但在航运业发达地区,由于受船行波的影响,很难得到稳定可靠的流速数据,阻碍了HADCP在平原河网地区的应用和推广。目前技术上很难做到完全消除船行波的影响,本文将HADCP应用在平原河网地区对流速进行测量,并分析了船行波对测量精度的影响。从H-ADCP设备选型、测量和安装方式、测量预处理、数据后处理等多方面入手,可以有效消减船行波对H-ADCP的影响,从而提高测流精度。同时,通过实验测量断面一天内平均流速变化情况,得到受船行波影响后的流速波形,然后采用数据处理手段,验证了所提方法的可行性。

基于熵权-云模型理论的河网水环境质量评价

针对目前河网水环境质量评价方法的不足,以浙江省嘉善县姚庄河网为例,选取DO、NH_(3)-N、TN、TP、COD五个指标作为评价指标,将姚庄河网划分为4个圩区,对18个水质监测断面进行现场采样和检测试验,将云模型理论融入熵权法中得到评价方法,对各水质监测断面进行水环境质量评价。结果表明,DO、NH_(3)-N所占权重分别为0.344、0.201,DO、NH_(3)-N是影响姚庄河网水环境质量评价结果的主要因素;姚庄圩区内部半数测点为Ⅳ类水,水环境质量急需改善。研究成果可为南方平原河网水环境质量的评定提供参考。

浙北平原河网地区典型湖漾水生态健康评价研究--以德清县苎溪漾为例

基于不同生境特征的水生态系统尚缺乏差异性评价标准的现实需求,本文以浙北平原河网地区湖漾水生态系统为切入点,采用一套针对其功能结构及区域特征的湖漾水生态健康评价体系,选取一个典型湖漾分别从物理生境、水质、沉积物和水生生物等4大要素13项指标开展水生态健康评价研究。结果表明,德清县最大的湖漾苎溪漾水生态健康状况为亚健康。其中,物理生境健康方面,苎溪漾生态缓冲带宽度较大、植被覆盖率较高,生境状况较好,为保护生物多样性创造了良好条件;水质健康方面,苎溪漾溶解氧充足、富营养化程度适当,抗生素影响小,水质条件较好。但是,从沉积物健康来看,苎溪漾底泥中总氮、总磷浓度较高,存在内源污染风险;从水生生物健康来看,苎溪漾杂食性鱼类占比较高,导致浮游植物及浮游动物多样性指数均较低,不利于湖漾水生态系统的平衡和稳定。建议苎溪漾在渔业养殖中适当降低杂食性鱼类的养殖密度,避免对浮游生物的过度摄食;并采取相应的措施减少周边农业种植以及生活污染源的输入,控制底泥内源污染的累积风险。

基于MIKE HYDRO River模型的轨交交通施工期防汛安全影响论证

轨交交通施工期间,受车站结构设计、周边场地限制等因素影响,河道需要断流施工,断流会对区域的防洪除涝安全及水环境产生影响。本文以上海轨道交通13号线西延伸工程为例,构建一维河网水动力模型,分析排涝及引调水工况下水位及水质变化情况。结果表明,平原河网地区个别河道断流对于区域防洪除涝安全影响较小,会严重影响河道断流处的水环境;通过增设导流措施可以减轻断流的影响,为平原河网地区河道断流影响分析及措施制定提供依据。