What is Sediment Hydraulics? part 1 : What is Sediment Hydraulics?

River during flood

• During a flood, a river is brown and muddy. This is due to the sediment transport with water.

in normal

flooding

Fig. A river in normal and flooding conditions [https://www.river.go.jp/index]

• The amount (concentration) of sediment transport depends on the flow of the river and catchment characteristics.

Fig. Confluence of Arve and Rhone rivers : [https://unsplash.com/]

多摩川と日原川の合流点

綺麗に半分こになってます！

ジュネーヴ・ジョンクシオン地方にあるアルヴ川とローヌ川の合流点みたい〜 pic.twitter.com/kY2z3zjLZE

— OgouchiBanbanCompany (@ogouchibanban) November 3, 2019

Fig. Confluence of Tama and Nippara rivers

Sediment transport in a river during a flood

There are different sizes of sediment during a flood: coarse sediment rolling along the river bed, slightly fine sediment jumping from the river bed, and much finer sediment suspending in water.

What is “Sediment Hydraulics”?

• A discipline that addresses problems caused by sediment transport in a river
• Although it is a part of hydraulics, it is often treated independently as “Sediment Hydraulics,” “Hydraulics of Sediment Transport,” etc.
• Many points are not yet clarified academically and have not been systematized.
• Difficulty is high in hydraulics.
• These classes of hydraulics are not really studied.

Key words of “Sediment Hydraulics”

“Sediment Transport”

• The sentiment moved by river flow

“River Bed Variation”

• The riverbed shape changes due to sediment transport imbalance.