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Discussion on the Construction of Negotiation Mechanism of Cross-bounder Water Pollution Treatment in Changjiang River 被引量:9
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作者 陈坤 《Meteorological and Environmental Research》 CAS 2010年第12期91-95,共5页
In order to construct cooperation platform for the treatment of water pollution in Changjiang River,thoughts and revolution were performed from both central government and regional area two aspects.From the national l... In order to construct cooperation platform for the treatment of water pollution in Changjiang River,thoughts and revolution were performed from both central government and regional area two aspects.From the national level,Changjiang region water resources management cooperation counsel committee was constructed as the national cooperation platform;from the regional level,Changjiang region water resources management cooperation counsel committee was constructed as the platform of Changjiang cooperation platform.The two platforms built fine interaction mechanism to deal with the national water management and Changjiang regional water management. 展开更多
关键词 Changjiang river cross-boundary water pollution NEGOTIATION China
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Geometric properties of river cross sections and associated hydrodynamic implications in Wuhan-Jiujiang river reach,the Yangtze River 被引量:2
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作者 张强 施雅风 熊明 《Journal of Geographical Sciences》 SCIE CSCD 2009年第1期58-66,共9页
Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou ... Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou and Tianjiazhen river reach). Hydrodynamic properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified between river-width/river-depth ratio (W/D ratio), sizes of cross section and mean flow velocity. Positive relations are detected between W/D ratio and mean flow velocity when W/D〈1; and negative relations are observed when W/D〉1. Adverse relationships can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel management in the middle Yangtze River basin. 展开更多
关键词 Wuhan-Jiujiang river reach river cross section hydrodynamic property Acoustic Doppler Current Profiler (ADCP)
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Road Lateral Disconnection and Crossing Impacts in River Landscape of Lancang River Valley in Yunnan Province,China 被引量:2
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作者 WANG Cong LIU Shiliang +2 位作者 DENG Li LIU Qi YANG Juejie 《Chinese Geographical Science》 SCIE CSCD 2014年第1期28-38,共11页
Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang Ri... Roads are conspicuous components in a river landscape;however,their impacts on river landscape patterns and ecological processes have not been systematically studied at the watershed scale.In this paper,the Lancang River Valley in Yunnan Province,China was selected as a case to study road lateral disconnection and crossing impacts and identify river-road network interaction.This study was primarily focused on the road impacts on soil erosion intensity and patch density by using GIS analysis at different scales and explored their distribution with terrain factors.The results showed that river density revealed spatial autocorrelation although both of the roads and rivers were distributed unevenly in the valley.The lateral road(road curvature≥1.1)proportion correlated with soil erosion intensity(p 0.01)at the small sub-basin scale.Soil erosion intensity decreased with increasing lateral road buffer width.Light erosion generally accounted for a large proportion of the erosion in the lateral road buffer zones(1.0–4.0 km),while higher class lateral roads imposed greater impacts on soil erosion than lower class roads,which primarily had a moderate erosion level.In addition,the results of road-river intersection density indicated that road crossing impacts were significantly correlated with patch density at the small sub-basin scale.Topography factor(percent of slope>25°in each sub-basin had a close relationship with the ratio of total length of road line with curvature value≥1.1 to the total number of intersections.The correlation(p 0.01)between road impacts and terrain factor revealed that topography affected the road impact distribution in the Lancang River Valley. 展开更多
关键词 lateral disconnection crossing impacts river landscape patch density soil erosion scale effect
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Effect of insufficient tunnel crown thickness on the post-tensioned concrete lining of the Yellow River Crossing Tunnel and its strengthening schemes 被引量:2
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作者 Qin Gan Cao Shengrong +1 位作者 Lai Xu Yang Fan 《Journal of Southeast University(English Edition)》 EI CAS 2018年第3期356-363,共8页
The effect of deficiency in tunnel crown thickness on the Yellow River Crossing Tunnel with post-tensioned concrete inner lining was investigated by the elasto-plastic finite element method. Changes in the deformation... The effect of deficiency in tunnel crown thickness on the Yellow River Crossing Tunnel with post-tensioned concrete inner lining was investigated by the elasto-plastic finite element method. Changes in the deformations and circumferential stresses of the post-tensioned concrete inner lining with the gradual decrease of the tunnel crown thickness were compared, and the potential bearing risk of insufficient tunnel crown thickness for the Yellow River Crossing Tunnel was revealed. Based on the finite element calculation results of circumferential stresses under different defective cases, the corresponding reinforcement schemes were proposed. The calculation results show that the inner lining can still maintain a satisfactory stress state when the tunnel crown thickness is equal to or greater than 0. 28 m. When the tunnel crown thickness decreases below 0.28 m, the external surface of the crown and internal surface of the crown's adjacent areas may be under tension. The tension stresses will incrementally increase and ultimately exceed the tensile strength of the inner lining concrete as the tunnel crown thickness further decreases gradually. Then, the Yellow River Crossing Tunnel cannot operate normally, and severe cracking, leaking or even failure may occur. When the tunnel crown thickness is equal to or greater than 0.28 m, the reinforcement suggestions are that the void spaces between the inner lining and the outer lining should be back-filled with concrete. When the tunnel crown thickness is less than 0. 28 m, the inner lining should be reinforced by steel plates after concrete back-filling. 展开更多
关键词 post-tensioned concrete linings runnel crownthickness stress redistribution finite element analysis tunnelreinforcement Yellow river crossing Tunnel
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Habitat fragmentation and the population status of rodents in Abayum forest, Ikom, Cross River State, Nigeria 被引量:1
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作者 Augustine Ugar Ogogo Francis Ebuta Bisong Abang Neji Tawo 《Natural Science》 2013年第8期914-918,共5页
The threat to wildlife population is attributed to various anthropogenic activities. The main objective of this study was to identify the influence of fragment size on the population density of rodents in the study ar... The threat to wildlife population is attributed to various anthropogenic activities. The main objective of this study was to identify the influence of fragment size on the population density of rodents in the study area. Fourteen (14) out of forty (40) fragments existing in the area were randomly sampled. The parameters used for the study were number, size of fragments and the corresponding population distribution of rodents in the study area. Fifty hunters in the area were also interviewed. The fragments were stratified into first, second and third order fragments on the basis of their sizes and randomly selected for the study. Indirect method of wildlife census was carried out through the observation of droppings, trail or tract, burrows, eating habits and noise. Fragment growth rate was 18 to 40 (87.5%) in 7 years. Anthropogenic perturbations in the form of cultivation of permanent cropland, settlement expansion, bush burning, timber exploitation and new settlements in areas previously thinly settled or not accessible to outsiders have resulted in disjointed ecosystems. The population density of rodents correlated with fragment size was highly significant ((P < 0.05) r = 0.9). It was then concluded that fragment size greatly influenced the population and diversity of rodent species. It was recommended that the remaining large fragments in the study area should be protected by law from further fragmentation. 展开更多
关键词 FOREST Fragmentation Rodent Population Abayum FOREST cross river STATE NIGERIA
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Physico-chemical indices of breeding sites of Simulium damnosum in the lower Cross River Basin, Nigeria
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作者 OPARA K. N. +1 位作者 FAGBEMI B. O. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第3期511-517,共7页
To determine the factor influencing the abundance development and distribution of Simulium damnosum(S.I) immature stages in the lower Cross River Basin, Nigeria, the physico-chemical characteristics of water at breedi... To determine the factor influencing the abundance development and distribution of Simulium damnosum(S.I) immature stages in the lower Cross River Basin, Nigeria, the physico-chemical characteristics of water at breeding sites were analysed longitudinally over a 12 month period. Analysis of the water samples showed that water current correlated positively and significantly(p<0.05), with dissolved oxygen(r = 0.95 vs 0.10); conductivity(r = 0.95 vs 0.81); hydrogen ion concentration(r = 0.03 vs 0.46); and biochemical oxygen demand(r = 0.80 vs 0.64); from Agbokim Waterfalls and Afi River respectively. The result indicates that these parameters and low ionic concentration are the most essential requirement for the development of S. damnosum pre-imaginal stages. Amplitudes of annual variability as measured by co-efficient of variation varied between the parameters. From the trends in hydrological variables it was deduced that the integrated impact of precipitation, input of surface runoff and municipal effluents played an overriding role in determining the absolute levels and temporal pattern in the water quality attributes. Of the 3578 pre-imaginal stages of S. damnosum collected, 52.52% and 47.4% were collected from Agbokim Waterfall and Afi River respectively. There was a significant difference(p<0.05) in the number of pre-imaginal stages collected from both sites. The highest number of pre_imaginal stages of S. damnosum collected were at the peak of rain(July—September) indicating that S. damnosum in the River Basin is a wet season breeder. The need for long term laboratory colonization of blackfly immature stages becomes imperative especially how these parameters could be exploited in control programme through the testing of larvicides without adverse ecological damage to the aquatic habitat. 展开更多
关键词 blackflies Simulium damnosum physico-chemical parameters lower cross river Basin Nigeria
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Ecosystems Services of the Tropical Rain Forest Environment: Lessons from the Cross River National Park, Nigeria
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作者 Benjamin A. Ambe Usang N. Onnoghen 《Journal of Geoscience and Environment Protection》 2019年第11期1-10,共10页
This paper essayed to examine ecosystem functions with a case study of the tropical rainforest environment of the Cross River National Park, Nigeria. The paper highlighted the important functions of the ecosystems to ... This paper essayed to examine ecosystem functions with a case study of the tropical rainforest environment of the Cross River National Park, Nigeria. The paper highlighted the important functions of the ecosystems to include Purification of air and water mitigation of floods and droughts, detoxification and decomposition of wastes, generation and renewal of soil and natural vegetation, pollination of crops and natural vegetation, control of the vast majority of potential agricultural pests, dispersal of seeds and translocation of nutrients, maintenance of biodiversity, protection from the sun’s harmful ultraviolet rays among others. Problems associated with the rainforest ecosystems among which are logging, traditional methods of farming, poaching, excessive noise and encroachment were identified. The paper concluded by highlighting the way forward among others that, awareness creation should be stepped-up in Support Zone Communities;indigenes should be educated periodically on the benefits of the ecosystem services to not just humans but the forest resources and biodiversity themselves. 展开更多
关键词 Ecosystem SERVICES Tropical RAINFORESTS cross river National PARK
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Evaluation of the Anti-Poaching Programme of the Cross River National Park Okwango Division, Nigeria 2002 to 2013
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作者 Augustine Ugar Ogogo Sijah Agbor Asuk Rebecca Victor Ikpeme 《Open Journal of Forestry》 2014年第5期507-511,共5页
Poaching of wildlife has continued to be the major problem confronting national parks managers in Nigeria in spite of effort being made to curb the ugly trend. This paper examined the anti-poaching programme of the Cr... Poaching of wildlife has continued to be the major problem confronting national parks managers in Nigeria in spite of effort being made to curb the ugly trend. This paper examined the anti-poaching programme of the Cross River National Park Okwango Division Nigeria from 2002 to 2013, with a view to making recommendations for the improvement of the programme. Focused group discussions, personal interviews, review of official records and structured questionnaires were used to collect data. Analysis of variance using randomized complete block design and student’s t-test were used to analyse data. Result showed that 1 - 5 arrests of poachers per month per patrol station was significantly (P 0.05) in the number of poachers arrested and fined between 2002 to 2006 and 2007 to 2011. The low performance of the anti-poaching programme was attributed to poorly equipped rangers’ posts as well as well the absence of alternative livelihood options in the enclave and surrounding communities. It was recommended that more rangers should be employed, and the rangers should be adequately kitted, well equipped patrol stations be constructed and the enclave and surrounding communities be involved in the management of the National Park in addition to providing them with alternative livelihood options. 展开更多
关键词 EVALUATION Anti-Poaching cross river National Park Okwango NIGERIA
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Species Composition and Gear Characteristics of the Macrobrachium Fishery of the Cross River Estuary,Nigeria
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作者 Francis M.Nwosu 《Journal of Ocean University of China》 SCIE CAS 2010年第1期71-75,共5页
The Cross River Estuary,Nigeria,is an important shrimping area for artisanal fishermen of the coastal communities.The multi-species Macrobrachium fishery is exploited with three main gears,namely beach seine,push net ... The Cross River Estuary,Nigeria,is an important shrimping area for artisanal fishermen of the coastal communities.The multi-species Macrobrachium fishery is exploited with three main gears,namely beach seine,push net and trap.Studies on species composition of this fishery recorded thirteen shrimp species,one swimming crab (Callinectes amnicola) and two fish species (Eleotris sp.and Pellonula leonensis).The shrimp species identified included Macrobrachium macrobrachion (83.39% and 55.69% by number and weight,respectively),M.vollenhovenii (9.66% and 37.18%),M.equidens (3.8% and 2.87%),juveniles-sub-adults of Penaeus notialis (1.11% and 1.3%),M.dux,M.felicinum,Palaemonetes africanus,Palaemon maculatus,Palaemon elegans,Desmocaris sp.,Leander sp.,Nematopalaemon hastatus and Alpheus pontederiae.While the selectivity index for trap was 0.25,beach seine and push net had a lower index of 0.063.The results present the first comprehensive and representative report for the Estuary shrimp fishery and will assist in the management of the biodiversity of this ecosystem. 展开更多
关键词 species composition gear characteristics Macrobrachium fishery cross river Estuary Nigeria
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Cross River Watershed Hydrologic Adjustment: Pre- and Post-June 2012 Mega-storm
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作者 Joe Magner Lu Zhang 《Journal of Environmental Science and Engineering(B)》 2014年第3期133-141,共9页
The Cross River watershed was disturbed by historic logging activity during the past century, but under the management of the USDA (United States Department of Agriculture) Forest Service, the area has mostly recove... The Cross River watershed was disturbed by historic logging activity during the past century, but under the management of the USDA (United States Department of Agriculture) Forest Service, the area has mostly recovered from ecological disturbance. Today a new threat is being imposed by climate change; changes affect not only the temperature but also more extreme wind and rain In 2012, a mega-storm event passed through the north shore region of Lake Superior overwhelming many watersheds with excessive rain and runoff. As part of a Cross River study for the Forest Service, pre- and post-event hydrologic adjustment of the Cross River watershed were captured. Samples were collected for δD and δ18O during April, July, and September to estimate HRT (hydraulic residence time) using the stable isotopes of hydrogen and oxygen, The results showed that water collected throughout the watershed shifted toward the signature of the mega-event precipitation signature, then slowly diffused with new precipitation and fractionation processes that resumed into the summer and fall. 展开更多
关键词 ISOTOPE hydraulic residence time cross river.
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Survey of Medicinal Plants Used in the Treatment of “Ailments of Utmost Native Importance” in Cross River State, Nigeria
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作者 Vincent Tawo Ebu Regina Ado Anoh +1 位作者 Raphael Ayama Offiong Pauline Ayuk Essoka 《Open Journal of Forestry》 2021年第3期330-339,共10页
Regardless of the high value of medicinal plants to residents of Cross River State in health maintenance especially for the treatment of “ailments of utmost native importance”, the major constraint is the uncertaint... Regardless of the high value of medicinal plants to residents of Cross River State in health maintenance especially for the treatment of “ailments of utmost native importance”, the major constraint is the uncertainty of the availability of the herbs and knowledge of traditional medicine still being passed by word of mouth. For better reliance on the plant species as medicine, this research seek</span><span style="font-family:Verdana;">s</span><span style="font-family:""><span style="font-family:Verdana;"> to identify and infer on the population and distribution of the species used in their treatment and documents them. Data were collected using field work and oral interviews. The survey team comprised of Taxonom</span><span style="font-family:Verdana;">ists, survey assistants, five trado-medical herbal practitioners and the Auth</span><span style="font-family:Verdana;">ors. </span><span style="font-family:Verdana;">The status and geographical distribution of the identified medicinal plant sp</span><span style="font-family:Verdana;">ecies was appalling, 59 percent of the medicinal plant species were distributed in 3 out of 15 sampled plots. Causal factors included over misuse of therapeu</span><span style="font-family:Verdana;">tic plant species, habitats destruction and absence of proper conservation ed</span><span style="font-family:Verdana;">ucation of the masses. Recommendations are that Communities should set up therapeutic plants farms, enrichment planting be made in agricultural fields and sustainable harvesting methods used. 展开更多
关键词 Medicinal Plants Ailments TREATMENT cross river
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On the National Symptoms of Boar Crossing the River:One Hundred Years of Solitude in a Malaysian Chinese Village
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作者 LI Lu 《Psychology Research》 2022年第5期294-304,共11页
After the famous“Rainforest Trilogy”such as Monkey Cup and Elephants,Zhang Guixing,a Malaysian Chinese writer in Taiwan,recently published another Nanyang story Boar Crossing the River,in the background of anti-Japa... After the famous“Rainforest Trilogy”such as Monkey Cup and Elephants,Zhang Guixing,a Malaysian Chinese writer in Taiwan,recently published another Nanyang story Boar Crossing the River,in the background of anti-Japanese War,focusing on the massacres and resistance of the Chinese in Krokop,a Malaysian Chinese village in Borneo from 1941 to 1945 according to a list of“Committee for the Relief of Refugees of the Motherland”.In this novel,Zhang Guixing changes the accustomed narrative mode of individual family history,expands the description to the group images of the Chinese in Krokop,highlights their patriotic sacrifice,and saves the reality of the slaughter of the compatriots by magic means such as the myths and legends of Borneo and masks in children’s imagination.It is also noteworthy that the novel talks about the relationship between individual freedom and national identity in depth,and describes the tragic fate of cross-national love in the period of national opposition.These nation-state discourses in Boar Crossing the River are Zhang Guixing’s biggest transitions when missing in the literary world for 17 years,which indicate a landmark progress in his spiritual history. 展开更多
关键词 Boar crossing the river Zhang Guixing national symptoms Malaysian Chinese literature
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Re-examination of Hydrochemistry and Groundwater Potentials of Cross River and Imo-Kwa-Ibo Intersecting Tropical Basins of South-South Nigeria
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作者 Saadu Umar Wali Ibrahim Mustapha Dankani +4 位作者 Sheikh Danjuma Abubakar Murtala Abubakar Gada Kabiru Jega Umar Abdulqadir Abubakar Usman Ibrahim Mohammad Shera 《Journal of Geological Research》 2020年第3期25-42,共18页
This review attempted a detailed description of geological and hydrogeological configurations of Cross River and Imo-Akwa Ibo basins.It presented a synthesis of hydrochemistry and a description of the hydrogeological ... This review attempted a detailed description of geological and hydrogeological configurations of Cross River and Imo-Akwa Ibo basins.It presented a synthesis of hydrochemistry and a description of the hydrogeological configurations of the two basins.Hydrogeologically,most areas under Cross River and Imo-Kwa-Ibo are poor in terms of groundwater potentials.Based on the hydrochemistry,the basins hold water of excellent quality.Groundwater sources fall in soft to moderately hard classes.The entire sources groundwater has a TDS concentration of less than 500 mg/l.Groundwater classification based on electrical conductivity(EC)showed EC levels were less than 500μS/cm.Most of the examined cations and anions are within WHO reference guidelines for drinking water quality.However,no broad analysis of water quality based on water quality indices.Also,studies modeling pollution or the impact of land use changes on groundwater quality are wanting.Thus,further analysis of the hydrochemistry of groundwater aquifers is recommended. 展开更多
关键词 cross river Basin Imo-Kwa-Ibo Basin HYDROGEOLOGY HYDROCHEMISTRY
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Vegetation Formation in Estuarine Tidal Flats: Influences of Basin Scale and River-Crossing Structures of the Eight Rivers of Ise Bay in Mie and Aichi Prefectures, Japan
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作者 Korehisa Kaneko Seiich Nohara 《Open Journal of Ecology》 2014年第15期974-988,共15页
In this study, we examined the influences of the differences in basin scale and river-crossing structures of 8 rivers of Ise Bay in Mie and Aichi Prefectures, Japan on the vegetation in the estuarine tidal flats of th... In this study, we examined the influences of the differences in basin scale and river-crossing structures of 8 rivers of Ise Bay in Mie and Aichi Prefectures, Japan on the vegetation in the estuarine tidal flats of these rivers. The dominant plant communities of the estuarine tidal flats formed from rivers of large-scale river basins (exceeding 300 km2) were determined. In the Miya River, the dominant plant community was the Suaeda maritima and Artemisia fukudo community. In the Kushida River, the dominant plant community was composed of Phacelurus latifolius, Artemisia fukudo, Phragmites australis, and bamboo. In the Kumozu River, the dominant community was composed of the coastal plants Calystegia soldanella, Lathyrus japonicus, and Carex pumila and the exotic plant of Lolium multiflorum. The plant community of Suzuka River was dominated by the exotic plant of Eragrostis curvula. Among the estuarine tidal flats influenced by a small-scale river basin (50 km2 or less), the plant community of Shinbori River (Fukue tidal flat) was dominated by Suaeda maritima, and the plant communities of the Shio and Harai Rivers were dominated by Phragmites australis. The plant community of Tanaka River was dominated by Phragmites australis and coastal plants. Regarding the relationship between the vegetation and the river environment for each study site, we hypothesised that in a large basin area with few structures crossing the river, the river water catchment in the estuary after heavy rains caused large areas of disturbance and formed bare land, providing suitable habitat for an annual salt marsh plant community. In contrast, in cases with many structures crossing the river, a stable channel, an excavated riverbed and the suppression of runoff and the resulting disturbance of the estuary, flooding did not occur during high tide. Moreover, we hypothesised that in a small basin with many structures crossing the river, disturbance to the estuary was not likely, and the perennial salt marsh plant community of Phragmites australis would be widely distributed, except for a river type such as the Shinbori River, in which tide and river flow were managed by a final closure. 展开更多
关键词 Annual SALT MARSH PLANT PERENNIAL SALT MARSH PLANT river-crossING Structure Water Level river Basin
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Horizontal freezing study for cross passage of river-crossing tunnel
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作者 Ming Zhang LingMin Wang +1 位作者 BaoWen Wang HongBao Lin 《Research in Cold and Arid Regions》 2011年第4期314-318,共5页
To determine the appropriate soft foundation treatment for a river-crossing tunnel, freezing reinforcement design and technology were introduced based on the channel tunnel design and construction practice. Through fi... To determine the appropriate soft foundation treatment for a river-crossing tunnel, freezing reinforcement design and technology were introduced based on the channel tunnel design and construction practice. Through finite element analysis and engineering practices, two rows of horizontal perforated freezing pipes were designed and installed on both sides of a passage for tunnel rein- forcement, which produced the thickness and strength of frozen crust that satisfied the design requirements. These information are valuable for guiding the design and construction of river-crossing tunnels in coastal areas. 展开更多
关键词 river-erossing tunnel cross passage horizontal freezing soft soil foundation
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Association of North Atlantic Oscillations with Aksu River runoff in China 被引量:2
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作者 李红军 江志红 杨青 《Journal of Geographical Sciences》 SCIE CSCD 2009年第1期12-24,共13页
The relationship between North Atlantic Oscillations (NAO) and Aksu River Runoff (ARR) was investigated by using the wavelet transform (WT), cross wavelet transform (CWT), correlation and linear trend analyses... The relationship between North Atlantic Oscillations (NAO) and Aksu River Runoff (ARR) was investigated by using the wavelet transform (WT), cross wavelet transform (CWT), correlation and linear trend analyses, and abrupt change test. The main results are as follows the interannual/decadal variation and period analyses of ARR and NAO reveal that the both were close correlated each other; the CWT indicates that the correlation was good between ARR and NAO at all periods in the 1990s, because the significant correlation areas mainly concentrated in the 1990s; the variations in the trend strength of ARR and NAO were consistent; the abrupt change of NAO was also temporally consistent with that of ARR, which exerted impact on the Aksu River Basin (ARB) climate and then the ARR through atmospheric circulation variation. 展开更多
关键词 Aksu river runoff NAO cross wavelet transform CORRELATION abrupt change test
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Channel change at Toudaoguai Station and its responses to the operation of upstream reservoirs in the upper Yellow River 被引量:53
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作者 RAN Lishan WANG Suiji FAN Xiaoli 《Journal of Geographical Sciences》 SCIE CSCD 2010年第2期231-247,共17页
The application of dams built upstream will change the input conditions, including water and sediment, of downstream fluvial system, and destroy previous dynamic quasi-equilibrium reached by channel streamflow, so ind... The application of dams built upstream will change the input conditions, including water and sediment, of downstream fluvial system, and destroy previous dynamic quasi-equilibrium reached by channel streamflow, so indispensable adjustments are necessary for downstream channel to adapt to the new water and sediment supply, leading the fluvial system to restore its previous equilibrium or reach a new equilibrium. Using about 50-year-long hydrological, sedimentary and cross-sectional data, temporal response processes of Toudaoguai cross-section located in the upper Yellow River to the operation of reservoirs built upstream are analyzed. The results show that the Toudaoguai cross-section change was influenced strongly by upstream reservoir operation and downstream channel bed armoring thereafter occurred gradually and extended to the reach below Sanhuhekou gauging station. Besides, median diameter of suspended sediment load experienced a three-stage change that is characterized by an increase at first, then a decrease and an increase again finally, which reflects the process of channel bed armoring that began at Qingtongxia reservoir and then gradually developed downstream to the reach below Sanhuhekou cross-section. Since the joint operation strategy of Longyangxia, Liujiaxia and Qingtongxia reservoirs was introduced in 1986, the three-stage change trend has become less evident than that in the time period between 1969 and 1986 when only Qingtongxia and Liujiaxia reservoirs were put into operation alone. In addition, since 1987, the extent of lateral migration and thalweg elevation change at Toudaoguai cross-section has reduced dramatically, cross-sectional profile and location tended to be stable, which is beneficial to the normal living for local people. 展开更多
关键词 cross-sectional profile median diameter reservoir Toudaoguai cross-section the upper Yellow river
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Analysis of Medicine Bow-Laramie River Drainage Divide Using Topographic Map Interpretation Techniques, Southeastern Wyoming, USA
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作者 Eric Clausen 《Open Journal of Geology》 2020年第7期741-759,共19页
Detailed topographic maps provide much of the information needed to understand how drainage divides like the southeast Wyoming Medicine Bow River-Laramie River drainage divide originated. Topographic map evidence for ... Detailed topographic maps provide much of the information needed to understand how drainage divides like the southeast Wyoming Medicine Bow River-Laramie River drainage divide originated. Topographic map evidence for each Medicine Bow-Laramie River drainage divide segment is here described and analyzed first using a commonly published interpretation (accepted paradigm) in which drainage routes developed on a surface of now mostly absent Oligocene and Miocene sediments that previous investigators have hypothesized to have once filled the Laramie Basin and to have also buried (or partially buried) the surrounding Laramie and Medicine Bow Mountains. Second, the same map evidence is analyzed using a recently proposed interpretation (new paradigm) in which massive and prolonged floods flowed across Wyoming as the Laramie and Medicine Bow Mountains began to be uplifted and as the southeast-oriented North Platte River valley eroded headward along the rising Laramie Mountains northeast flank. Low points along the drainage divide (referred to as divide crossings) are interpreted to be places where water once flowed across the drainage divide with the drainage divide being formed when capture events diverted the water in other directions. Valleys leading away from divide crossings are used to determine the nature of observed capture events, many of which are difficult or impossible to explain from the accepted paradigm perspective, but which are consistent with the mountain uplift, headward erosion of deeper valleys, and/or draining of floodwaters trapped in the Laramie Basin as the new paradigm predicts. However, the new paradigm requires a North American continental ice sheet heavy enough to raise entire regions and mountain ranges as massive and prolonged meltwater floods flowed across them, something the accepted paradigm does not recognize. 展开更多
关键词 Divide crossing GEOMORPHOLOGY Laramie Basin Medicine Bow Mountains North Platte river
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水下穿越管道检测新技术——水下机器人River-ROV外腐蚀检测 被引量:6
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作者 郝毅 《全面腐蚀控制》 2018年第8期21-25,共5页
长输油气管道的水下穿越管道由于安全、施工及环境等问题,急需进行腐蚀与防护状况的检测。在这种背景下,为满足管道管理运行单位的需求,融合了多种先进技术的江河水下管道外腐蚀检测系统River-ROV被开发出来,它能够通过实施电信号采集... 长输油气管道的水下穿越管道由于安全、施工及环境等问题,急需进行腐蚀与防护状况的检测。在这种背景下,为满足管道管理运行单位的需求,融合了多种先进技术的江河水下管道外腐蚀检测系统River-ROV被开发出来,它能够通过实施电信号采集及电磁法探测等手段人对水下穿越管道进行检测,同时获取管道的腐蚀与防护状况。通过实际工程检测,也验证了该技术在国内的水下穿越管道检测中的实用性。 展开更多
关键词 水下穿越管道 水下机器人river-ROV 外腐蚀检测
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水下穿越管道外腐蚀检测评价系统River-ROV的应用性研究 被引量:1
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作者 申耀东 曹强 +1 位作者 邓宝信 李雪阳 《全面腐蚀控制》 2023年第5期98-101,共4页
长输油气管道的江河水下穿越管道由于施工和和环境等问题使得管道面临严峻的腐蚀损伤风险,由于缺乏对应的技术手段,绝大多数穿越管段未能开展相关的检测。在全国长输油气管道大力度提升管道安全管理的背景下,迫切地需要先进的检测手段,... 长输油气管道的江河水下穿越管道由于施工和和环境等问题使得管道面临严峻的腐蚀损伤风险,由于缺乏对应的技术手段,绝大多数穿越管段未能开展相关的检测。在全国长输油气管道大力度提升管道安全管理的背景下,迫切地需要先进的检测手段,本文采用江河水下River-ROV检测技术进行应用性研究和试验,选取两处大开挖穿越管段的管道为代表,验证了其技术的适用性和可靠性,实现水下穿越管道的外腐蚀状况检测和评价,为水下穿越管道的维护维修项目提供全面准确有效的数据支持,运营安全管理形成操作性强的技术支持。 展开更多
关键词 水下穿越管道 river-ROV 外腐蚀检测评价
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