河流环境关心点的位置定量化

提出了河流环境关心点的概念，即指河流两岸或河中体现或影响河流环境功能的环境要素与河流某断面相互作用的点。阐述了河流环境关心点与位置定量化之间的关系及编制点位图时应遵循的功能原则、水质原则和边界原则，指出河流环境关心点位图能够比较直观、全观地反映各点位分布情况。以沅江为例，叙述了绘制各环境关心点位的方法。     

Time Series Analysis to Monitor and Assess Water Resources: A Moving Average Approach

An understanding of the behavior of the groundwater body and its long-term trends are essential for making any management decision in a given watershed. Geostatistical methods can effectively be used to derive the long-term trends of the groundwater body. Here an attempt has been made to find out the long-term trends of the water table fluctuations of a river basin through a time series approach. The method was found to be useful for demarcating the zones of discharge and of recharge of an aquifer. The recharge of the aquifer is attributed to the return flow from applied irrigation. In the study area, farmers mainly depend on borewells for water and water is pumped from the deep aquifer indiscriminately. The recharge of the shallow aquifer implies excessive pumping of the deep aquifer. Necessary steps have to be taken immediately at appropriate levels to control the irrational pumping of deep aquifer groundwater, which is needed as a future water source. The study emphasizes the use of geostatistics for the better management of water resources and sustainable development of the area.     

How Hydrologic Connectivity Regulates Water Quality in River Corridors

Downstream flow in rivers is repeatedly delayed by hydrologic exchange with off‐channel storage zones where biogeochemical processing occurs. We present a dimensionless metric that quantifies river connectivity as the balance between downstream flow and the exchange of water with the bed, banks, and floodplains. The degree of connectivity directly influences downstream water quality — too little connectivity limits the amount of river water exchanged and leads to biogeochemically inactive water storage, while too much connectivity limits the contact time with sediments for reactions to proceed. Using a metric of reaction significance based on river connectivity, we provide evidence that intermediate levels of connectivity, rather than the highest or lowest levels, are the most efficient in removing nitrogen from Northeastern United States’ rivers. Intermediate connectivity balances the frequency, residence time, and contact volume with reactive sediments, which can maximize the reactive processing of dissolved contaminants and the protection of downstream water quality. Our simulations suggest denitrification dominantly occurs in riverbed hyporheic zones of streams and small rivers, whereas vertical turbulent mixing in contact with sediments dominates in mid‐size to large rivers. The metrics of connectivity and reaction significance presented here can facilitate scientifically based prioritizations of river management strategies to protect the values and functions of river corridors.     

广州市感潮水源河段重金属分布特征及健康风险评价

对广州市沙湾水道(感潮河流型饮用水源地)涨、退潮期间13个断面7种重金属含量进行监测,并应用化学致癌和化学非致癌健康风险评价模型对该感潮河段重金属进行健康风险评价,研究该感潮河段重金属含量及其健康风险的时空分布特征。结果表明:该感潮河段重金属具有显著的空间分布差异,而感潮作用对重金属含量的影响并不明显;该感潮河段化学非致癌重金属污染物健康风险值相对较低,Cu、Hg、Zn的年平均风险值为10-10a-1,远远低于瑞典、荷兰、英国推荐的可接受限值,而化学致癌重金属污染物所引起的人体健康危害较高,化学致癌重金属污染物As、Cd的年平均风险值分别为10-5 a-1和10-6 a-1,其中Cd的年平均风险值与瑞典、荷兰、英国推荐的可接受限值接近(1×10-6 a-1),As的年平均风险值接近国际(ICRP)推荐值(5×10-5 a-1),致癌风险极大,应优先加以控制。     

Determination of estrogenic activity in the river Chienti (Marche Region, Italy) by using in vivo and in vitro bioassays

Environmental estrogen-like compounds (i.e. xenoestrogens) are a variety of pollutants, ranging from synthetic to natural occurring molecules, that are found in surface and waste waters over a wide range of concentrations. In aquatic environment, the overall estrogenic activity is often due to the presence of a mixture of chemicals and their degraded products which can induce synergistic effects. Current strategies for monitoring estrogen-like chemicals are based on the use of a battery of in vivo and in vitro ecotoxicological tests. In this regard, the aim of the present work was to carry out a bio-monitoring study for testing estrogenicity of the Chienti river (Marche Region, Italy) by using both an E-screen and a vitellogenin (Vtg) induction assay in juvenile goldfish. Three sites were used for analysis, localized at the mouth (sampling point 1), in the middle (sampling point 2) and at the origin (sampling point 3) of Chienti river. For most of the water samples (i.e. samples collected at sampling points 2 and 3), clear estrogenic activity was detected in the E-screen assay suggesting different proliferation activities in function of the collecting site. In contrast, the Vtg ELISA demonstrated that water samples collected from each sampling point were estrogenic. Overall, we showed for the first time that the estrogenic activities in water samples from the Chienti river were significant in both in vivo and in vitro; we also observed a different sensitivity between bioassays.     

絮凝浓缩武汉市巡司河底淤泥的研究

目的研究武汉市巡司河底淤泥在不同无机絮凝剂及PAM的助凝作用下淤泥清浑分界面的沉降速率、淤泥浓缩比以及淤泥沉降指数的变化情况。方法采用实验研究的方法,对巡司河底淤泥进行沉降实验,并通过沉降分析找到最佳脱水效果的脱水剂。结果当淤泥质量分数为10%时,Ca(OH)2取得的絮凝脱水效果最好,Ca(OH)2投加比为5 g/L,PAM投加比为0.04 g/L时,淤泥清浑分界面的沉降速率最大可达到3.7 cm/min,淤泥浓缩比为3.94,淤泥沉降指数为24.9%。结论 Ca(OH)2和PAM对巡司河底淤泥的脱水有促进效果,淤泥在Ca(OH)2和PAM共同作用下先后经历了自由沉降、絮凝沉降、区域沉淀和压缩沉降。     

基于主成分分析法对安肇新河水质评价的研究

安肇新河为大庆市的南线排水系统的主要排水干渠.安肇新河河道北起王花泡滞洪区,南抵松花汪,东邻肇兰新河,西至大庆市西排干,流域形状基本上为狭长形,河道的主要任务是排泄古恰闸以上七个滞洪区及各区间的来水.由于运用单因子综合评价法无法对安肇新河的水质进行比较分析,特引入主成分分析法对近十年数据进行分析,进一步比较了安肇新河时间和空间上的水质变化情况.通过对因子选择和计算,对安肇新河近10年的数据进行空间和时间的科学比对,进行综合比较并作出时间和空间上的评价.     

宁波杭州湾新区河网水动力及水质数值模拟研究

针对杭州湾新区水环境污染较重的现状,采用MIKE11软件构建新区河网的一维水动力——水质耦合模型,在此基础上研究分析了现状及远期规划排污条件下河网水质分布.结果表明:河道内水体流动较弱,不利于污染物迁移扩散,污水处理厂排出的处理水对排污口周围的河道的水质影响范围和程度均较大,叠加本底浓度后许多区域超过了Ⅴ类水质标准.最后提出了针对性措施以改善新区河网水质.     

Towards Real‐Time Continental Scale Streamflow Simulation in Continuous and Discrete Space

The National Weather Service (NWS) forecasts floods at approximately 3,600 locations across the United States (U.S.). However, the river network, as defined by the 1:100,000 scale National Hydrography Dataset‐Plus (NHDPlus) dataset, consists of 2.7 million river segments. Through the National Flood Interoperability Experiment, a continental scale streamflow simulation and forecast system was implemented and continuously operated through the summer of 2015. This system leveraged the WRF‐Hydro framework, initialized on a 3‐km grid, the Routing Application for the Parallel Computation of Discharge river routing model, operating on the NHDPlus, and real‐time atmospheric forcing to continuously forecast streamflow. Although this system produced forecasts, this paper presents a study of the three‐month nowcast to demonstrate the capacity to seamlessly predict reach scale streamflow at the continental scale. In addition, this paper evaluates the impact of reservoirs, through a case study in Texas. Validation of the uncalibrated model using observed hourly streamflow at 5,701 U.S. Geological Survey gages shows 26% demonstrate PBias ≤ |25%|, 11% demonstrate Nash‐Sutcliffe Efficiency (NSE) ≥ 0.25, and 6% demonstrate both PBias ≤ |25%| and NSE ≥ 0.25. When evaluating the impact of reservoirs, the analysis shows when reservoirs are included, NSE ≥ 0.25 for 56% of the gages downstream while NSE ≥ 0.25 for 11% when they are not. The results presented here provide a benchmark for the evolving hydrology program within the NWS and supports their efforts to develop a reach scale flood forecasting system for the country.     

Historical and Future Stream Temperature Change Predicted by a Lidar‐Based Assessment of Riparian Condition and Channel Width

Riparian forests attenuate solar radiation, thereby mediating an important component of the thermal budget of streams. Here, we investigate the relationship between riparian degradation, stream temperature, and channel width in the Chehalis River Basin, Washington State. We used lidar data to measure canopy opening angle, the angle formed between the channel center and trees on both banks; we assumed historical tree heights and calculated the change in canopy angle relative to historical conditions. We then developed an empirical relationship between canopy angle and water temperature using existing data, and simulated temperatures between 2002 and 2080 by combining a tree growth model with climate change scenarios from the NorWeST regional prediction. The greatest change between historical and current conditions (~7°C) occurred in developed portions of the river network, with the highest values of change predicted at channel widths less than ~40 m. Tree growth lessened climate change increases in maximum temperature and the length of river exceeding biologically critical thresholds by ~50%–60%. Moreover, the maximum temperature of channels with bankfull widths less than ~50 m remained similar to current conditions, despite climate change increases. Our findings are consistent with a possible role for the riparian landscape in explaining the low sensitivity of stream temperatures to air temperatures observed in some small mountain streams.