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EXPERIMENT OF IMPACT OF RIVER HYDRAULIC CHARACTERISTICS ON NUTRIENTS PURIFICATION COEFFICIENT 总被引:3,自引:0,他引:3
WANG Pei-fang WANG Xiao-rong WANG Chao 《水动力学研究与进展(B辑)》2007,19(3):387-393
Hydraulic characteristics of a river are the key factors for river water quality improvement and river restoration. A simulated river was exploited to study the interactions between water contaminant purification coefficients and the characteristics of the river, such as the cross-section velocity, water depth, Reynolds number, and Froude number. To enhance the purification capacity of the river, detritus with 5 mm to 10 mm in diameter and contact surface area per volume of 87.6 m2/m3 were constructed naturally at the bed and along one side of the bank to form half shape of the river cross-section. During the one-month experiment (including 3 periods) from the third of November to the fourth of December, 2005, three categories of hydraulic conditions were investigated. Results show that the purification coefficient (K) of Total Nitrogen (TN) is closely coherent with the hydraulic retention time (T), river length (L), Reynolds number (Re) and Froude number (Fr). The relationship of K and T generally agrees with the power law under the three experimental water hydraulic conditions. Based on these results, the optimal Re and Fr ranges can be obtain to serve as a guideline for ecological re-engineering design to improve river water quality and restore river ecosystem. 相似文献
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D. A. Freitas J. J. S. P. Cabral F. J. S. Rocha A. L. R. Paiva M. L. Sens T. B. Veras 《河流研究与利用》2017,33(7):1079-1087
In bank filtration (BF) technology, a production well is pumped near surface water and induces water flow from the river through a porous medium to the well by percolation into the soil. Several physical, chemical, and biological processes occur, providing a natural water treatment along the river banks. An experimental area was installed on the Beberibe River with 2 production wells and 7 monitoring wells. The BF potential in removing pathogenic intestinal parasites and analysis of physical–chemical and bacteriological parameters was evaluated, according to Standard Methods. River–aquifer interaction was characterized by piezometric levels of production wells. Monitoring of the wells was correlated with the water depth of the river and precipitation. Parasite analysis was performed using Hoffman, Pons, and Janer's methods of spontaneous sedimentation, followed by centrifugation and preparation of slides stained with acetic Lugol. Protozoa oocysts were isolated by a modified Ziehl‐Neelsen method, preceded by sedimentation and centrifugation. The pathogenic protozoa found in samples from Beberibe River were Cryptosporidium spp., Giardia spp., Entamoeba histolytica/dispar complex, and Isospora belli. Pathogenic helminths were also detected: Ascaris lumbricoides, Strongyloides stercoralis, and hookworm eggs and larvae, Hymenolepis nana. In water samples from the production wells, no waterborne pathogens were found. The BF pilot project was effective in reducing levels of turbidity and color. Total coliforms and Escherichia coli were absent in the production wells. Piezometric levels of production wells and monitoring wells correlated with water depth of Beberibe River show hydraulic connection between the production wells and river, thus featuring a river–aquifer interaction. The BF pilot system showed potential for reduction or elimination of pathogenic intestinal parasites. 相似文献
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Nadine Wittmann 《Water Resources Management》2014,28(5):1309-1325
Water scarcity is becoming an increasingly relevant issue in many regions of the world as demand for water continues to grow. As a result, the need for finding measures that efficiently allocate increasingly scarce water resources has become a primary topic on the agendas of many water resource management authorities. This paper presents an innovative approach that provides further insight into the connection between hydrological, environmental, and economic aspects along a river basin. In short, it analyzes how land rents along a river basin are affected by managing water pollution along a river basin, given certain hydrological characteristics of the river basin. Results show that, without the implementation of a water management system to control water quality, the negative external effects of upstream water discharges on downstream locations can be internalized through a decrease in downstream land rents. However, the analysis presented in this paper also reveals that it is not only the absence or the presence of a water management system that has a significant impact on the real estate market along the river basin. Moreover, the market outcome also varies with the type of water resources management system implemented. 相似文献
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调水引流改善平原河网水环境质量模拟 总被引:2,自引:0,他引:2
为科学定量地评估引调水工程对平原河网地区城市内河水质的改善效果,以张家港市中部水系为例,运用MIKE11构建了河网水动力水质耦合模型,模拟了沿江水利枢纽和内河节制闸不同的调度方式对城市内河水质的影响,利用水质浓度改善率探究了水利调度改善城市内河水质的程度。结果表明:增加沿江水利枢纽引水天数对改善城市内河水质有显著作用,但随着引水天数的增加,NH_3-N浓度改善率日均提升幅度逐渐降低;内河节制闸调度工况对改善城市内河水质起到一定的促进作用,实际调水引流工作中可作为一种辅助措施。 相似文献
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结合长江口深水航道治理二期工程北槽中整治建筑物的布置形式,在潮汐往复流水槽中进行了丁坝群不同布置形式的概化试验,试验结果表明,在深水区的单侧丁坝群对宽浅河床地形的调整作用大于浅水区:双侧丁坝群的联合作用能调整深水区的平面位置;合理地选择治导线的放宽率,能有效地调整深槽平均水深的沿程变化. 相似文献
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潮河生态修复治理措施及效果分析 总被引:1,自引:0,他引:1
潮河是潮白河的主要支流,存在的主要问题是:一防洪标准低,缺少控制性工程;二河道侵蚀冲刷严重;三潮河两岸面源污染严重等,严重威胁着首都北京的饮用水安全.为保障北京市供水安全,采取了工程措施和生物措施相结合的方式,对潮河两岸进行生态修复,治理河长87.68 km,其中工程措施防护61.13 km,生物措施防护32.79 km.工程实施后,恢复了潮河河流的生态环境质量,效果显著. 相似文献
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纵向一维水温模型研究 总被引:2,自引:0,他引:2
根据热传导理论建立了模拟河道水温沿程变化的纵向一维数学模型,并讨论了模型参数的取值方法。将模型应用于金沙江某河段的水温模拟,得出了比较准确的水温沿程分布情况。 相似文献
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为了利用爆破解决黄河下游河道经常出现的横河和斜河威胁河道安全的险情以及河道整治中的裁弯取直、疏浚航道和河道引水口淤积的问题,在黄河湿滩上进行了微差爆破开槽试验研究。通过试验,回答了在黄河下游湿滩上能否进行爆破开槽施工;爆破能否形成沟槽,形成的沟槽可以保持多长时间;能否作为引槽引水,通过冲刷形成新河槽;爆破开槽对已有工程的安全影响等四方面的问题。 相似文献
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《Journal of Great Lakes research》2022,48(2):336-342
Observation of phytoplankton and water chemistry along the main channel of the St. Lawrence River was made at a high spatial resolution (every 12 km) in order to infer the factors that influence development of this phytoplankton community. The phytoplankton community in the main channel was collected over a 10-d period (mid July 2018) from the headwaters to near the beginning of the St. Lawrence River estuary. Total phosphorus concentration in river water increased with distance downstream (154–2,750 nM) and phytoplankton biomass (1.4–10.5 µg chl-a/L) was strongly correlated (r = 0.84, 46 d.f.) to the concentration of total phosphorus. Diatoms, chrysophytes and dinoflagellates dominated the phytoplankton community at the outlet of Lake Ontario and total chlorophyll-a concentrations increased three-fold with 500 km transit downstream from Lake Ontario; phycocyanin-rich Cyanobacteria showed the greatest proportional increase (227%). Total P concentrations observed in 1997 along this transect were identical to those observed in 2018; however, chl-a concentrations were much lower in 1997, a finding attributed to a greater filter feeding benthic organism impact on the standing crop of phytoplankton. Observations support the hypothesis that the phytoplankton community composition in this large river is strongly influenced by the headwater characteristics (Lake Ontario) and gradually influenced by entrainment of nutrient-rich tributary waters. 相似文献
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《Journal of Great Lakes research》2001,27(2):220-229
Elevated levels of indicator bacteria within a river system represent a significant impairment to surface water quality in many urban areas within the Great Lakes watershed. Outfalls from combined sewer systems are assumed to be the major source of bacteria to streams in many of these urban areas, including the Rouge River of southeastern Michigan. Current remediation strategies largely disregard other potential sources, including water entering the river from its headwaters region, rural runoff, and contaminated groundwater. These other potential sources of bacterial pollution to the Rouge River were assessed and compared with bacteria contributed from combined sewer outfalls (CSOs). Fecal coliform (FC) and fecal streptococci (FS) densities were determined at 28 locations in the Rouge River Watershed during the spring and summer of 1997, 1998, and 1999. The mean levels of both indicator groups vary considerably along each branch of the river and show no correlation to CSO locations. The magnitude of both FC and FS levels are, in fact, frequently greater at sites upstream of the part of the river influenced by discharges from CSOs. The highest FC levels coincided with rainfall events, but FC levels at various sites along each branch of the Rouge River violated acceptable water quality standards (200 colonies/100 mL) at nearly 50% of the sites even during dry weather. Total suspended solids were moderately correlated with FC (r = 0.79) throughout the watershed, suggesting that solids may play a role in transporting bacteria into the Rouge River. The data depict a strong influence of upstream water and rural runoff on the water quality of the Rouge River. FC to FS ratios (FC/FS) suggest the primary source of bacteria throughout the watershed is from domesticated animals and wildlife and not from sewage derived from CSOs. 相似文献
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三峡水库蓄水后,葛洲坝枢纽下游近坝河段内枝城枯水位降幅较小,但宜昌及宜都等位置枯水位降幅较大,且随时间变化显示出非均匀下降的特征。为揭示该现象成因,依据宜昌至枝城河段内枯水位、地形、河床组成等实测资料分析了各因素的时变特征,并采用分离变量法计算分析了枯水位非均匀下降的机理。结果表明:宜昌枯水位在2008年前降幅小且下降速度慢,2008年以后降幅增大且下降速度加快;宜都至枝城区间冲刷是引起宜昌枯水位下降的主导因素,宜都以上河床变形、枝城水位下降为次要因素;宜都以上河床粗化引起阻力调整,是导致2008年前宜昌枯水位降幅小的主要原因;2012年后,宜昌至枝城段河床变形和阻力调整余地都已不大,未来宜昌枯水位稳定性主要取决于枝城水位变幅。 相似文献
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针对概化的"葫芦"区河段,采用概化非恒定流,模拟了不同规模"葫芦"区的河道行洪情况,探究了"葫芦"河段滩区规模对其河道行洪影响。模拟结果表明:(1)"葫芦"区对其进(出)口起到引流减阻作用(坦化作用),对河道起到明显调蓄作用,河道拓宽比为0.30时效果最为显著;(2)"葫芦"区滩区分流能力随着河道拓展宽度的增加而增强,沿程先增大后减小,且随着流量增加滩区分流比最大值断面向下游推移。总体来看,涨水时,滩区分流比减小;落水时,滩区分流比增加,且较断面流量过程有一定相位延迟;(3)河道拓宽比0.30可作为一般河道"葫芦"区保留宽度的下限,河道"葫芦"区的实际保留宽度需视情况具体分析。 相似文献
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江水源热泵系统以江水作为热泵系统的热源为建筑物供热或供冷,在建设节约型社会、国家节能减排的形式下,在沿江有条件的地区已推广使用。该文通过重庆江北城CBD天然河床渗滤+人工河床渗滤+直取水联合取水工程,提出了一种适合江水源热泵的取水技术。 相似文献
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Changes in water quality that occur as water flows along hyporheic flow paths may have important effects on surface water quality and aquatic habitat, yet very few studies have examined these hyporheic processes along large gravel bed rivers. To determine water quality changes associated with hyporheic flow along the Willamette River, Oregon, we studied hyporheic flow at six‐bar deposit sites positioned between the main river channel and connected lentic alcoves. We installed piezometers and wells at each site and measured water levels and water quality in river, hyporheic and alcove water. Piezometric surfaces along with substrate characteristics were used to determine hyporheic flow path direction and hyporheic flow rate. At all sites, hyporheic flow moved from the river through bar deposits into alcove surface water. Stable isotope analysis showed little influence of upwelling groundwater. At a majority of sites, hyporheic dissolved oxygen and ammonium decreased relative to river water, and hyporheic specific conductance, nitrate and soluble reactive phosphorous increased relative to river water. At three sites, hyporheic temperature decreased 3–7°C relative to river water; there was less temperature change at the other three sites. At the two sites with the highest hyporheic flow rates, hyporheic cooling was propagated into the alcove surface water. Hyporheic changes had the greatest effect on alcove water quality at sites with highly permeable substrates and high‐hyporheic flow rates. The best approach to enhancing hyporheic flows and associated water quality functions is through restoring fluviogeomorphic channel processes that create and maintain high‐permeability gravel deposits conducive to hyporheic flow. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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Recently, New Jersey has experienced several droughts and declared several critical water shortage areas, spurring interest in reducing freshwater resource depletion. Japanese knotweed (Reynoutria japonica Houtt.) is an invasive plant species that may have a significant effect on stream water loss. In order to assess the impact of this species on river-level water flow, we estimated total knotweed distribution along two tributaries of the Passaic River in New Jersey, USA using a combination of field measurements and GIS to calculate total daily water loss to the atmosphere from three stands of knotweed along these rivers. We measured total leaf area of each stand and transpiration rates across each stand from sun-up to sun-down. The average water loss was 8.5 L wate/day/m2 of ground area covered in knotweed. Knowing the total distribution of knotweed along each river, the amount of river length covered by knotweed stands and the total water lost to the atmosphere per amount of knotweed along each river we were able to estimate the total amount of water transpired to the atmosphere by knotweed per river on a daily basis during its growing season. These results were compared to summer low flow rates to assess the impact on river flow during the growing season for Japanese knotweed. Our results suggest that knotweed along these rivers is reducing total flow by an average of 8% (approximately 800,000–1,400,000 L/day) during the summer months. This is important as the impact of invasive species on water resources in temperate areas is currently under-studied in ecohydrology. 相似文献