北塘排污河天津中心城区段恶臭污染调查与分析研究

为研究天津市中心城区北塘排污河恶臭污染特征,沿北塘排污河布设5个采样点位,分别在夏、秋、冬三季进行了系统采样.北塘排污河夏、秋、冬三季总检出浓度为23.842 5 mg/m^3,夏季（9.273 1mg/m^3）＞冬季（8.388 4 mg/m^3）＞秋季（6.181 0 mg/m^3）,靖江桥和兵营桥两个点位受赵沽里泵站出水水质的影响较大,对周围的恶臭污染程度更为严重.北塘排污河污染物质总检出浓度组成特征：无机气体＞含氧烃＞烷烃＞芳香烃＞卤代烃＞烯烃＞硫化物,共检出物质67种,检出率大于70％的污染物共30种,广泛存在的物质为11种,主要恶臭污染物为少量的含氧烃、无机气体和硫化物,乙醛、丙酮、硫化氢和甲硫醇为北塘排污河主要恶臭污染物.     

人工湿地植物床-沟壕系统水质净化效果

嘉兴市石臼漾湿地以仿拟自然界的植物床-沟壕系统为主要结构单元,以人工湿地生态根孔技术为核心净化技术,将河网源水主要水质指标提高了一个类别.为探索该系统以及根孔净化技术的优化途径,于2010年5～10月在湿地内构建了16个并联的植物床-沟壕单元,以正交设计手段研究根孔构筑方式、植物组合和强化介质3种因素对人工湿地植物床-沟壕系统水质净化效果的影响.综合考虑水质净化效果、工程施工难易程度、建设及运行维护成本等情况,推荐人工湿地植物床-沟壕系统的优化途径为:根孔构筑方式采用上、下两层秸秆填埋方式,植物组合优选芦苇+菰,在植物床局部采用适量方解石作为强化介质.比较了中试强化区和大工程区的水质净化效率,结果显示:强化后的植物床-沟壕系统具有进一步提升湿地水质净化效果的潜能,对总氮、总磷、氨氮等水质指标去除率提高幅度约为20%～40%.因此在保证湿地处理水量的前提下,控制大渠过水量、增加植物床-沟壕系统内根孔区的过流量可以发挥该系统更好的水质净化效果.     

R134a在水平环形通道内的凝结换热性能

在空气源热泵热水器中,对水平套管冷凝器环形通道内R134a的凝结换热特性进行实验研究。在冷凝器不同进水流量、进水温度时,实验测试了水平套管冷凝器凝结换热系数随热流密度、冷凝压力及干度的变化。实验工况为:冷凝器的进水流量为0.6~1.0 m~3/h,进水温度为15~60℃。实验结果表明:水平环形通道内R134a的凝结换热系数随热流密度和冷凝压力(温度)的升高而减小,当冷凝压力为1.3 MPa,热流密度由18 k W/m2增加至20.5 k W/m~2时,R134a的凝结换热系数减小了6.9%;当热流密度为15 k W/m~2,冷凝压力由1.78 MPa增大至1.83 MPa时,R134a的凝结换热系数减小了5.8%。R134a的局部凝结换热系数随干度的增大而增大,当冷凝压力为1.1 MPa,热流密度为18.3 k W/m~2,制冷剂干度由0.1增大至0.9时,R134a的局部凝结换热系数增大了24.4%。     

Extent and Channel Morphology of Unmapped Headwater Stream Segments of the Quabbin Watershed,Massachusetts1

Brooks, Robert T. and Elizabeth A. Colburn, 2011. Extent and Channel Morphology of Unmapped Headwater Stream Segments of the Quabbin Watershed, Massachusetts. Journal of the American Water Resources Association (JAWRA) 47(1):158‐168. DOI: 10.1111/j.1752‐1688.2010.00499.x Abstract: Effective regulatory protection and management of headwater resources depend on consistent and accurate identification and delineation of stream occurrence. Published maps and digital resources fail to represent the true occurrence and extent of headwater streams. This study assessed the accuracy of mapped origins of “blue‐line” streams depicted on U.S. Geological Survey topographic maps, and, if present, the morphological characteristics of unmapped stream segments. We identified 170 mapped stream origins on the Quabbin Reservoir watershed, Massachusetts. Of 30 mapped stream origins, we identified and examined 26 unmapped stream segments above 25, with an average length of 502 m. Twenty unmapped tributaries occurred on 10 of the 26 unmapped segments, with an average length of 127 m. Wetland reaches occurred more frequently and were larger on unmapped than on mapped stream segments. A significant and complex stream network occurs above most mapped stream origins. For the Quabbin watershed, we estimate that there are 85.8 km of unmapped stream upgradient of 314.5 km of mapped streams. Reliance on mapped stream networks for regulatory standards allows for the potential disturbance or even destruction of the unmapped stream resources. Jurisdictional regulations and guidelines should be revised so that the occurrence of streams should require field validation.     

Improved Bankfull Channel Geometry Prediction Using Two‐Year Return‐Period Discharge1

He, Laien and Gregory V. Wilkerson, 2011. Improved Bankfull Channel Geometry Prediction Using Two‐Year Return‐Period Discharge. Journal of the American Water Resources Association (JAWRA) 47(6):1298–1316. DOI: 10.1111/j.1752‐1688.2011.00567.x Abstract:  Bankfull discharge (Q_bf) and bankfull channel geometry (i.e., width, W_bf; mean depth, D_bf; and cross‐section area, A_bf) are important design parameters in stream restoration, habitat creation, mined land reclamation, and related projects. The selection of values for these parameters is facilitated by regional curves (regression models in which Q_bf, W_bf, D_bf, and A_bf are predicted as a function of drainage area, A_da). This paper explores the potential for the two‐year return‐period discharge (Q₂) to improve predictions of W_bf, D_bf, and A_bf. Improved predictions are expected because Q₂ estimates integrate the effects of basin drainage area, climate, and geology. For conducting this study, 29 datasets (each representing one hydrologic region) spanning 14 states in the United States were analyzed. We assessed the utility of using Q₂ by comparing statistical measures of regression model performance (e.g., coefficient of determination and Akaike’s information criterion). Compared to using A_da, Q₂ is shown to be a “clearly superior” predictor of W_bf, D_bf, and A_bf, respectively, for 21, 13, and 25% of the datasets. By contrast, A_da yielded a clearly superior model for predicting W_bf, D_bf, and A_bf, respectively, for 0, 0, and 14% of the datasets. Our conclusion is that it alongside with developing conventional regional curves using A_da it is prudent to develop regional curves that use Q₂ as an independent variable because in some cases the resulting model will be superior.     

A Sediment Budget for an Urbanizing Watershed, 1951‐1996, Montgomery County, Maryland,U.S.A.1

Abstract: Despite widespread interest, few sediment budgets are available to document patterns of erosion and sedimentation in developing watersheds. We assess the sediment budget for the Good Hope Tributary, a small watershed (4.05 km²) in Montgomery County, Maryland, from 1951‐1996. Lacking monitoring data spanning the period of interest, we rely on a variety of indirect and stratigraphic methods. Using regression equations relating sediment yield to construction, we estimated an upland sediment production of 5,700 m³ between 1951 and 1996. Regression equations indicate that channel cross‐sectional area is correlated with the extent of development; these relationships, when combined with historical land use data, suggest that upland sediment yield was augmented by 6,400 m³ produced by enlargement of first‐order and second‐order stream channels. We used dendrochronology to estimate that 4,000 m³ of sediment was stored on the floodplain from 1951‐1996. The sediment yield from the watershed, obtained by summing upstream contributions, totals 8,100 m³ of sediment, or 135 tons/km²/year. These results indicate that upland erosion, channel enlargement, and floodplain storage are all significant components of the sediment budget of our study area, and all three are approximately equal in magnitude. Erosion of “legacy” floodplain sediments originally deposited during poor agricultural practices of the 19th and early 20th Centuries has likely contributed between 0 and 20% of the total sediment yield, indicating that these remobilized deposits are not a dominant component of the sediment yield of our study area.     

阶梯形鱼道中的滚动流研究(英文)

最近 ,小型倾斜河流中的阶梯形鱼道建筑以它的简易与实用而变得日益重要。在这种鱼道中出现的滚动流将产生波涌 ,并继续向下传播 ,而且它的周期性滚动可能会严重危害鱼道。因此 ,我们着手研究了它的严重性以便设计者在设计鱼道时能考虑这些因素。由实验证实滚动流源于阶梯形鱼道的上游。滚动流在稳定流与半平滑流间转变 ,它在一定时间间隔内不断地从稳定流变成半平滑流 ,又从半平滑流变成稳定流。它的流量值随着阶梯形水道的几何形状变形而呈现上下限。流量值和时间间隔均随着水池长度的增加而增加。     

Ecological wetland paradigm drives water source improvement in the stream network of Yangtze River Delta

Jiaxing created a precedent using bypass riparian marshes to purify micro-polluted water sources in China. Pond-wetland complex with constructed root channel technology becomes a paradigm which can be analogized as “human-body wetland model” based on bionics or biomimetics. Heterogeneous plant-bed/ditch system with highly active land/water ecotone interfaces, especially meandering boundaries, breeds many biochemical reactions “living areas”. Optimization of hydraulic regulation promotes redox environment alternations and wetland treatment efficiency. Here we reported a series of upgrades and performances in Guanjinggang wetland after the Shijiuyang prototype. Morphological reform of plant-bed/ditch system played a vital role. Spatially root channel zone was main force of wetland purification, and temporally the treatment effect was higher in low-temperature seasons indicating non-temperature dependent mechanisms worked. Water pollution comprehensive index improved steadily from IV to III, and comprehensive pollution load was reduced by ca. 40%–60%. Comprehensive evaluation function value further showed the gradients purification effect of the upgraded wetland. Ecological wetlands ameliorated source water quality, and reduced drinking water treatment reagents, thereby bringing about economic benefits. Through wetlands operation, people can see how the micro-polluted surface water becomes clear and clean, so promoting a significant social benefit. As a viable component of urban green space, wetlands could beautify regional eco-environment, freshen the air, increase urban ecological taste, and enhance the eco-environmental protection publicity. Thus, the multifunctional service values and indirect benefits are substantial. Jiaxing ecological wetlands provide a typical paradigm for water pollution remediation in developing countries and plays a leading role in technology engineering radiation effect.     

Channel Roughness in North Carolina Mountain Streams

Channel roughness, often described by Manning's n, is used to represent the amount of resistance that flow encounters, and has direct implications on velocity and discharge. Ideally, n is calculated from a long‐term record of channel discharge and hydraulic geometry. In the absence of these data, a combination of photo references and a validated qualitative method is preferable to simply choosing n arbitrarily or from a table. The purpose of this study was to use United States Geological Survey (USGS) streamflow data to calculate roughness coefficients for streams in the mountains of North Carolina. Five USGS gage stations were selected for this study, representing drainage areas between 71.5 and 337 km². Photo references of the study sites are presented. Measured discharges were combined with hydraulic geometry at a cross‐section to calculate roughness coefficients for flows of interest. At bankfull flow, n ranged between 0.039 and 0.064 for the five study sites. Roughness coefficients were not constant for all flows in a channel, and fluctuated over a large range. At all sites, roughness was highest during low‐flow conditions, then quickly decreased as flow increased, up to the bankfull elevation.     

莱州湾南岸平原古河道及其与海（咸）水入侵关系研究

海（咸）水入侵作为莱州湾南岸平原的一种新的环境灾害,其发生、发展与该区广泛分布的古河道密切相关。本文研究了古河道的分布规律、沉积特征及分期,并重点探讨了其与海（咸）水入侵的密切关系。古河道是该区海（咸）水入侵的主要通道,古河道中海（咸）水入侵速度快、方式多、周期性变化明显,是灾情是严重、入侵变化最复杂的地貌单元;古河道又是防治海（咸）水入侵的天然工程,古河道砂层径流条件好,只要采取措施提高其地下淡