Effects of sediment replenishment on riverbed material size distribution and attached algal biomass in the downstream reaches of a dam

IF 0.6 Q4 WATER RESOURCES

Hydrological Research Letters Pub Date : 2017-01-01 DOI:10.3178/HRL.11.114

Yukio Miyagawa, T. Sumi, Y. Takemon, Sohei Kobayashi

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引用次数: 4

Abstract

Sediment replenishment is an effective method for resupplying depleted sediment and detaching overgrown algae in the downstream reaches of a dam. In this study, we used empirical data to examine the effects of sediment replenishment on bed material size and algal biomass in the downstream reaches of the Futase Dam, Chichibu City, Saitama Prefecture, Japan. Assuming that algae detach from bed materials when they are moved by water flow, we calculated the tractive force on the riverbed (τ) and allotted a threshold bed material size in motion (Dcri) for each given τ. The resulting bed material in the downstream reaches of the dam in any year was typically finer than that in the previous year when flooding in the rainy season transported a large volume of sediment. Algal biomass was lower when monthly Dcri exceeded 2 mm, versus when it was less than 2 mm. These results suggest that replenishment of fine bed materials accelerates algal detachment and restricts the accumulation of algal biomass by reducing bed stability.

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泥沙补给对大坝下游河床物质粒径分布及附着藻生物量的影响

泥沙补给是大坝下游补沙、脱藻的有效手段。本研究以日本埼玉县秩父市Futase大坝下游为研究对象，研究了泥沙补给对河床大小和藻类生物量的影响。假设藻类在被水流移动时与河床物质分离，我们计算了河床上的牵引力(τ)，并为每个给定τ分配了一个阈值运动河床物质尺寸(Dcri)。在任何一年，大坝下游产生的河床物质通常都比前一年更细，而前一年雨季的洪水会携带大量的沉积物。月Dcri大于2 mm时，藻类生物量低于月Dcri小于2 mm时。这些结果表明，细床物质的补充加速了藻类的分离，并通过降低床的稳定性来限制藻类生物量的积累。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Hydrological Research Letters WATER RESOURCES-

CiteScore

1.90

自引率

18.20%

发文量

审稿时长

10 weeks

期刊介绍： Hydrological Research Letters (HRL) is an international and trans-disciplinary electronic online journal published jointly by Japan Society of Hydrology and Water Resources (JSHWR), Japanese Association of Groundwater Hydrology (JAGH), Japanese Association of Hydrological Sciences (JAHS), and Japanese Society of Physical Hydrology (JSPH), aiming at rapid exchange and outgoing of information in these fields. The purpose is to disseminate original research findings and develop debates on a wide range of investigations on hydrology and water resources to researchers, students and the public. It also publishes reviews of various fields on hydrology and water resources and other information of interest to scientists to encourage communication and utilization of the published results. The editors welcome contributions from authors throughout the world. The decision on acceptance of a submitted manuscript is made by the journal editors on the basis of suitability of subject matter to the scope of the journal, originality of the contribution, potential impacts on societies and scientific merit. Manuscripts submitted to HRL may cover all aspects of hydrology and water resources, including research on physical and biological sciences, engineering, and social and political sciences from the aspects of hydrology and water resources.