共查询到19条相似文献,搜索用时 140 毫秒
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《人民黄河》2017,(7):48-50
潼三河段采用主河槽断面间距和滩间距计算库容和淤积量,受河道形态变化、水库低水位运行和治黄工程修建等影响,原有部分淤积测验断面已经失去控制主河槽的代表性,淤积测验断面间距发生变化,沿用的固定主河槽断面间距影响库容及淤积量的计算精度。分析了潼三河段沿用主河槽断面间距计算淤积量存在的问题,采用断面线中点连接法、断面两侧边线平均法量算主河槽断面间距,并进行淤积量计算,分析断面间距变化对淤积量计算精度的影响,结果表明:在计算模型和方法不变的情况下,只考虑主河槽断面间距因素,用新主河槽断面间距计算出的淤积量较用原间距计算结果均增大,说明一直沿用的主河槽断面间距影响淤积量计算的准确性;河段总间距增大,淤积量也增大,淤积量与断面间距成正比关系。 相似文献
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潼关高程推算的基本方法是:用潼关水文站实测流量和相应水位资料,点绘水位—流量关系曲线或建立水位—流量关系的表达式,经过查图或解析计算,求出潼关(六)断面流量1000m^3/s时所对应的水位。通过分析潼关高程推算中的水位—流量关系,认为:将潼关(六)断面1000m^3/s流量时的水位作为潼关高程这一指标不宜改动;有关潼关高程的具体数据的有效时段是与推得潼关高程的特定水位—流量关系的有效时段相一致的;河段变化与断面迁移给潼关(六)断面水位推算带来的问题需要认真分析,并在此基础上选择合适的计算方法;在提供潼关高程数据时,应详细说明引用的资料和所采用的方法。 相似文献
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交界断面的水量是目前水环境综合治理和水环境管理考核的重要数据,对跨界河流水量水质目标考核有着重要意义。利用现有实测降雨量,通过建立交界断面以上流域降雨径流关系推求时段径流量,能够满足一定精度要求,是过渡期推算交界断面水量的可行方法。 相似文献
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河道中受侧壁影响的断面流速分布规律研究 总被引:1,自引:0,他引:1
断面水流流速分布是研究河道水流泥沙运动规律的基础。天然河流断面形态不同,其流速分布特性也有差别:对于比较宽浅的河道,侧壁对断面流速分布的影响较小,流速沿垂线分布梯度较大,垂线上最大流速一般位于水面,垂线平均流速沿河宽方向(横向)分布较均匀;对于较窄深的河道,侧壁对流速分布的影响较大,流速沿垂线分布较均匀,垂线上最大流速一般位于水面以下,垂线平均流速沿河宽分布梯度较大,因此,对于较窄深的河道必须考虑侧壁对流速分布的影响。本文在分析天然河道流速分布特性的基础上,从紊流的雷诺方程出发,推导获得了水流受侧壁影响的横断面流速分布公式和垂线平均流速沿河宽分布的公式。公式计算结果与水槽试验和天然河流实测流速分布资料的比较分析表明,公式能较好地反映流速沿垂线和沿横向的分布特性,具有较好的理论和实用价值。 相似文献
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天然河流的横断面多为由主槽和漫滩组成的复式断面,水流在这种断面中比在单一断面中受到更多因素影响,流态也更加复杂。通过将明渠横断面上微元体在水流方向的N-S控制方程沿水深积分,得出描述垂线平均流速和边界剪切应力横向分布的模型,并通过对实验数据的验证,确定了模型的实用性。 相似文献
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Rapid Response of a Sand‐Dominated River to Installation and Removal of a Temporary Run‐of‐the‐River Dam
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Run‐of‐the‐river dams (RORDs) comprise the vast majority of dams on river systems and are commonly removed as a part of stream restoration strategies. Although these dams are routinely removed, few studies have documented the geomorphological responses of sand‐bed rivers to the removal of RORDs. We examined the response of a large sand‐bed river located in South‐Central Kansas, USA, to the installation and removal of a dam that is installed annually for seasonal recreational purposes. Channel adjustments were tracked using cross‐sections sampled over the course of 7 months as the dam was installed and subsequently removed. Multivariate spatiotemporal analysis revealed emergence of channel stability when the dam was in place for most cross‐sections, except for those immediately adjacent to or at great distances from the dam. Our results provide an approximation for how sand‐bed rivers respond to RORD construction and removal and are useful for guiding management decisions involving preservation or restoration of connectivity. Results of this study suggest that sand‐bed rivers are resilient and recover quickly when transient RORDs are removed. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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根据广东省中小河流生态治理经验,按照不同类型河道生态治理需求,归纳提炼出缓坡型、陡坡型自然护岸以及垂直式、斜坡式、复合式人工护岸等生态景观护岸断面形式,并结合七拱河综合整治工程,详细说明断面形式的设计过程。提出的断面形式能满足河道防洪排涝、引水灌溉、景观生态、休闲娱乐等多功能需求,对于各种不同类型中小河流治理的生态景观护岸断面形式设计具有一定的参考意义。 相似文献
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为探讨对三口分流河道的治理原则,根据对三口分流河道特性及演变规律的分析研究,提出了分流河道的治理原则:无调洪效果的两汊间的横河应予堵塞;对主要河道在可能的条件下将其断面导向窄深;适当的堵塞归并一些支汊,以便束水攻沙、减缓淤积和水位抬高,减缓堤防加高的速度,特别是减少堤防长度,改变荆南防洪线长面广的被动局面。 相似文献
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T. Skalski R. Kędzior B. Wyżga A. Radecki‐Pawlik K. Plesiński J. Zawiejska 《河流研究与利用》2016,32(9):1968-1977
The impact of river incision induced by channelization and gravel mining on the structure of ground beetle assemblages in riparian habitats was investigated on three montane rivers in southern Poland. Ground beetles were collected on three benches of different elevation in 11 incised and 14 vertically stable cross sections of the rivers. In total, 5821 individuals representing 106 species were collected. The effect of river incision on the diversity and abundance of ground beetles depended on bench height. Only on the lowest bench, inundated about once per year on average, species richness of the assemblages was significantly reduced in incised river cross sections. On this bench, the abundance of the specialists of exposed riverine sediments, i.e. small and medium‐sized predators with high dispersal power and spring breeding strategy, was highly negatively affected by river incision. On the highest bench, large, brachypterous species with spring and autumn breeding strategy, typical of undisturbed habitats, were more abundant in incised cross sections. As this bench is practically not subjected to flooding even in vertically stable cross sections, these species probably benefited from the occurrence of riparian forest along most incised river sections, whereas the riparian areas along vertically stable sections are subjected to higher agricultural pressure. This study shows that in the mountain region where high precipitation helps to maintain moisture of the riparian habitats, river incision has a negative impact only on the specialists of exposed riverine sediments. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献