Chapter 2 Diversion components

Which of the followings tell you lies

• Emergency spillways is designed for extreme conditions or a serious malfunction of the service spillway

• Crest elevation of gated spillway is equal to Normal water level.

• Embankment dams are made of local materials like earth, rock, earth-rock, steel, concrete…

• Water retaining structures raise up the water level, regulate the flow and create reservoir

What are similarities between diversion headwork and storage headwork?

• Regulate the flow and control the water head upstream

• Create storage volume to utilize in dry season

• Overflow in excess of water or flood water during flood season

• Raising up the water level upstream for water resources utilization purposes

Listing names of weir from left to right, up to down

What are components of diversion headwork?

• Barrages/Weirs, stilling basins, Intakes, channels, silt excluder

• Guide bank, Concrete apron, spillway body, chute, stilling basin

• Gate tower, bulkhead, trash rack, channel

• Apron, wingwall, step spillway, flip bucket, downstream channels

Point out names of components from 1 to 7

Based on this weir equation state several ways to increase the flow rate discharge Q that you know?

What are differences between barrages and weirs?

• A barrage can create a large storage volume but a weir can create a small pondage

• A barrage is equipped radial/vertical gate to control the flow passing by but a weir is not

• A barrage is cheaper and long-term constructed but a weir is more expensive and short-term constructed

• A barrage is low crested and valve gates and its operation device put on top, but a weir is high crested and it is without gates

What are characteristics of upstream apron?

• Direct the flow centrally and shaped contraction

• Reinforce the bed foundation to avoid erosion from the current

• It is made of rip rap/concrete block, including permeable layers

• It helps avoid erosion on bed foundation

Nhue river diversion work which does not contain barrages or weirs. In which hydrological and hydraulic conditions are a diversion work without weirs/barrages apply? (hints: think of water head)