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61.
基于GS和DEM的九龙江流域地表水 总被引:6,自引:3,他引:6
运用GIS软件ARC/INFO、ArcView,以九龙江流域为例,探讨了数字高程模型(DEM)的处理及其水文模拟分析。对九龙江流域分幅数字高程模型(DEM)进行图幅拼接、网格重分及切割等处理分析,生成九龙江流域数字高程模型。基于DEM和GIS,进行流域的水文模拟分析,包括洼地填充、水流方向计算、水流累积量计算、水网提取,最后进行了九龙江全流域及子流域界线的划分,生成了数字流域。 相似文献
62.
Ecological impacts of small hydropower plants on headwater stream fish: from individual to community effects 下载免费PDF全文
Lluís Benejam Sandra Saura‐Mas Mònica Bardina Carolina Solà Antoni Munné Emili García‐Berthou 《Ecology of Freshwater Fish》2016,25(2):295-306
Hydroelectricity is increasingly used worldwide as a source of renewable energy, and many mountain ranges have dozens or hundreds of hydropower plants, with many more being under construction or planned. Although the ecological impacts of large dams are relatively well known, the effects of small hydropower plants and their weirs have been much less investigated. We studied the effects of water diversion of small hydropower plants on fish assemblages in the upper Ter river basin (Catalonia, NE Spain), which has headwater reaches with good water quality and no large dams but many of such plants. We studied fish populations and habitat features on control and impacted reaches for water diversion of 16 hydropower plants. In the impacted reaches, there was a significantly lower presence of refuges for fish, poorer habitat quality, more pools and less riffles and macrophytes, and shallower water levels. We also observed higher fish abundance, larger mean fish size and better fish condition in the control than in impacted reaches, although the results were species‐specific. Accordingly, species composition was also affected, with lower relative abundance of brown trout (Salmo trutta) and Pyrenean minnow (Phoxinus bigerri) in the impacted reaches and higher presence of stone loach (Barbatula quignardi) and Mediterranean barbel (Barbus meridionalis). Our study highlights the effects of water diversion of small hydropower plants from the individual to the population and community levels but probably underestimates them, urging for further assessment and mitigation of these ecological impacts. 相似文献
63.
Salinity and geomorphology drive long‐term changes to local and regional fish assemblage attributes in the lower Pecos River,Texas 下载免费PDF全文
River systems throughout arid regions worldwide have been heavily impacted by human activities, resulting in long‐term ecological consequences. The lower Pecos River in the Trans‐Pecos region of Texas is no exception, having undergone anthropogenic changes that include decreased flow, elevated salinity, species loss and species invasion. We compared historical and contemporary fish assemblage attributes from the Pecos River at local (site‐specific) and regional (Trans‐Pecos region) scales across a 24‐year time period. Fish assemblage data were collected in October 1987 and 2011, by seining at 15 sites spanning 430 km of the river in Texas. Additionally, we examined contemporary environmental conditions to determine species–environment relationships. We found that fish assemblages were significantly different between time periods, likely due to increased salinisation in the upper half of the study region. Decreased species richness, species replacement and increases in euryhaline species were documented in the upstream sites. Freshwater springs lower the salinity and maintain flows in the downstream reach, allowing for maintenance of the native fish fauna. Careful management of regional aquifers, irrigation practices and petroleum waste water will be necessary for protecting biodiversity and environmental flows in the lower Pecos River. 相似文献
64.
The only known extant population of the diamond darter (Crystallaria cincotta) exists in the lower 37 km of Elk River, WV, USA. Our understanding of diamond darter habitat use was previously limited, because few individuals have been observed during sampling with conventional gears. We quantified microhabitat use of diamond darters based on measurements of water depth, water velocity and per cent substrate composition. Using spotlights at night‐time, we sampled 16 sites within the lower 133 km of Elk River and observed a total of 82 diamond darters at 10 of 11 sampling sites within the lower 37 km. Glides, located immediately upstream of riffles, were the primary habitats sampled for diamond darters, which included relatively shallow depths (<1 m), moderate‐to‐low water velocities (often < 0.5 m·s?1) and a smooth water surface. Microhabitat use (mean ± SE) of diamond darters was estimated for depth (0.47 ± 0.02 m), average velocity (0.27 ± 0.01 m·s?1) and bottom velocity (0.15 ± 0.01 m·s?1). Substrate used (mean ± SE) by diamond darters was predominantly sand intermixed with lesser amounts of gravel and cobble: % sand (52.1 ± 1.6), % small gravel (12.2 ± 0.78), % large gravel (14.2 ± 0.83), % cobble (19.8 ± 0.96) and % boulder (1.6 ± 0.36). Based on our microhabitat use data, conservation and management efforts for this species should consider preserving glide habitats within Elk River. Spotlighting, a successful sampling method for diamond darters, should be considered for study designs of population estimation and long‐term monitoring. 相似文献
65.
长三角经济发展战略定位中探索图书馆发展的新模式 总被引:1,自引:0,他引:1
周莉 《农业图书情报学刊》2010,22(8):11-15
21世纪长三角经济发展必须要有一个正确的战略定位,区域内图书馆以此为指导,统一理念,共同探索图书馆发展的新模式。基于长三角经济发展现状的分析,提出了21世纪长三角经济发展的战略定位对图书馆建设与发展的影响,并阐述了构建特色的馆藏建设是图书馆发展的基础。 相似文献
66.
67.
20世纪20年代末30年代初,中国历史上形成了一次大规模的"乡村建设运动"。作为"足以代表这个运动的整个方面之较早者"——中华职业教育社"鉴于农村的衰落,与一般农业学校造就的人材,不合实际的需要,并且不能担当挽救农村衰落的重任,主张改变方向,把职业教育的范围扩大,深入到农村里去",(1)积极投入到乡村建设运动中,在长江三角洲地区展开了一系列的乡村建设活动。 相似文献
68.
69.
漯河市沙澧河公园植物配置模式应用技术探讨 总被引:1,自引:0,他引:1
在漯河市沙澧河公园植物营造过程中,科学筛选适宜品种,充分利用乡土树种,进行合理配置,营造连续性滨河公园园林景观,构建地带性植物群落,既美化了环境,也保证了生态平衡。 相似文献
70.
人工湿地作为一种污水生物处理技术,因其具有独特的优势,已得到广泛的应用。针对五岳河水污染现状,结合人工湿地处理废水的特点,从场地选择、工艺类型选择等方面论述利用人工湿地法解决五岳河水污染问题的可行性。 相似文献