Assessment of Reservoir Sedimentation Effect on Coastal Erosion and Evaluation of Sediment Removal Techniques for Its Reduction — The Case of Nestos River, Greece

Assessment of reservoir sedimentation effect on coastal erosion in the case of Nestos River, Greece

International Journal of Sediment Research ◽

10.1016/s1001-6279(14)60020-2 ◽

2014 ◽

Vol 29 (1) ◽

pp. 34-48 ◽

Cited By ~ 15

Author(s):

M. ANDREDAKI ◽

A. GEORGOULAS ◽

V. HRISSANTHOU ◽

N. KOTSOVINOS

Keyword(s):

Coastal Erosion ◽

Reservoir Sedimentation ◽

Nestos River

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Planning and Analysis of Sedimentation Countermeasures in Hydropower Dams Considering Properties of Reservoir Sedimentation

Journal of Disaster Research ◽

10.20965/jdr.2018.p0702 ◽

2018 ◽

Vol 13 (4) ◽

pp. 702-708 ◽

Cited By ~ 3

Author(s):

Chihaya Onda ◽

Tetsuya Sumi ◽

Tsuyoshi Asahi ◽

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...

Keyword(s):

River Flow ◽

Reservoir Sedimentation ◽

Sediment Properties ◽

Sediment Removal ◽

Postwar Reconstruction ◽

Sediment Routing ◽

Routing Methods ◽

Reconstruction Period ◽

High Degree ◽

Near Future

Sedimentation in hydropower reservoirs is one of the most important problems facing power generation. Many of the reservoirs our company’s dams, built in the postwar reconstruction period, have been storing up sedimentation for decades. The percentage of sedimentation is now considerable, about 9%, because of a combination of a high degree of sediment production and the river flow regime. We have been trying to excavate the sedimentation from the reservoirs to avoid aggradations of upstream riverbeds and to eliminate obstacles to intake and outlet functions. Considering sediment properties, we have carried out representative five different ways of managing reservoir sediment. At the Sakuma dam, which is comparatively large, provisional transporting inside the reservoir is the main countermeasure, but radical management will be required in the near future. At the Futatsuno dam and Taki dam, which are medium-sized, the current volume of sedimentation excavation is not sufficient to maintain the size of the reservoir, due to flow sedimentation. Sediment routing methods, such as bypassing, will therefore be urgently planned. At the Setoishi and Yambara dams, the testing of sediment sluicing or hydro-suction sediment removal systems has already started. Regarding sedimentation sluicing, we have studied the feasibility of sediment bypass tunnels and gated outlets in the dam reservoir that is unsuitable for sluicing with the existing spillway. We found that gated outlet will be effective. Although there are no quick remedies that can reduce reservoir sedimentation dramatically, there are some methods that may be suitable, considering the size, life and basin of each reservoir. Not only the technical feasibility, but also the economic advantages and ecological acceptability should be considered. To sustain reservoirs and hydropower, sedimentation should be managed effectively and adaptively, based on the specific conditions of each reservoir.

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Coastal Erosion Problems along the Northern Aegean Coastline: The Case of the Nestos River Delta and the Adjacent Coastlines

Coastal Systems and Continental Margins - Soft Shore Protection ◽

10.1007/978-94-010-0135-9_24 ◽

2003 ◽

pp. 337-348

Author(s):

G. S. Xeidakis ◽

P. Delimani

Keyword(s):

Coastal Erosion ◽

River Delta ◽

Nestos River

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Experimental study of pressure flushing of non-cohesive sediment through slotted pipe bottom outlet

RBRH ◽

10.1590/2318-0331.262120200076 ◽

2021 ◽

Vol 26 ◽

Author(s):

Felipe Azevedo Paulo ◽

Aline Saupe Abreu ◽

Maurício Dai Prá ◽

Luiz Augusto Magalhães Endres ◽

Rute Ferla ◽

...

Keyword(s):

Experimental Data ◽

Cohesive Sediment ◽

Reservoir Sedimentation ◽

Sediment Characteristics ◽

Direction Parallel ◽

Sediment Removal ◽

New Type ◽

Bottom Outlets ◽

Dimensionless Relation ◽

Bottom Outlet

ABSTRACT Among several techniques for prevention and mitigation of reservoir sedimentation, bottom outlets arise as a means of removing sediment deposited close to the dam. Given the reduced sediment removal provided by traditional bottom outlets under pressure flushing conditions, this article proposes a new type of structure that aims to increase sediment removal in the direction parallel to the dam axis. An experimental installation was employed to evaluate its operation as a function of the variation of its diameter and flow and sediment characteristics. Through analysis of the bathymetry generated by the structure, a dimensionless relation for predicting the scour pit length was obtained, presenting good fitness to the experimental data.

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