What is apron in weir?

2. Upstream apron: It protect it during floods from eroding action. Its length depends upon discharge of river and weir's length. It also help to prevent leakage in subsoil and it minimizes uplift water pressure if any exist.

What is Crest in weir?

The weir crest is the upstream element of a pair of boundary elements simulating a weir. The corresponding downstream element is the weir slope.

What is a weir trough?

Fiberglass Troughs and weir pans for circular, square, rectangular or custom tanks. The uses are for filtering, thickening, clarification, flocculation, scum removal or back wash. The products are available in NSF/ ANSI 61 certified and AWWA F101 compliant materials and properties.

What is gravity weir?

The gravity weir is the weir in which uplift pressure below the weir due to seepage is fully resist by the self weight of the weir. In the case of non-gravity weirs the thickness of the floor is kept relatively small and uplift pressure is largely resist by the bending action of the reinforc concrete floor.

What is barrage and components?

Main barrage portion:

Main body of the barrage, normal RCC slab which supports the steel gate. In the X-Section it consists of : Upstream concrete floor, to lengthen the path of seepage and to project the middle portion where the pier, gates and bridge are located.

Weirs and Launching Apron

What is Crest in barrage?

The crest level in the barrage (top of solid obstruction) is kept at low level. During flood, gates are raised to clear of the high flood level. As a result there is less silting and provide better regulation and control than the weir.

What is pond level in weir?

(vii) Pond Level:

The weir stores water on its upstream side in front of a head regulator to create a still pond. The canal gets water from this pond through the head regulator . Hence, it is essential to keep the level of the pond some 0.75 to 1 m above the FSL of the canal to provide sufficient working head.

What is weir length?

The Length is the bottom width of the weir. The height is measured from the bottom of the weir opening to the top of the water level ponded behind the weir (not the water level right as it leaves the weir).

What are under sluices?

: a sluice covered from view or lying beneath another structure specifically : a wasteway for sluicing out canals in which the waste escapes beneath other structures.

What is vertical drop weir?

ADVERTISEMENTS: Vertical drop weir is such a weir, whose D/S face is given steep batter. The U/S face is mostly vertical, but it can also be given batter like D/S face.

What is weir overflow?

A weir is an overflow structure that is used to alter flow characteristics. In the example below, the water is flowing from left to right. The black triangular-shaped structure is the weir. It is impeding the flow of water causing the water to flow over the weir structure.

What is notch and weir?

A notch is an opening in the side of a measuring tank or reservoir extending above the free surface. A weir is a notch on a large scale, used, for example, to measure the flow of a river, and may be sharp edged or have a substantial breadth in the direction of flow.

What is weir diameter?

weir diameter (weer)

The diameter of the weir is the length of a line from one edge of a weir to the opposite edge and passing through the center of the circle formed by the weir.

What is chute spillway?

A chute spillway is a common and basic design that transfers excess water from behind the dam down a smooth decline into the river below. These are usually designed following an ogee curve. Most often, they are lined on the bottom and sides with concrete to protect the dam and topography.

What is end contraction of weir?

An end contraction is when the length of the weir (L) is less than the width of the Channel and a nappe contracts either one or both sides of the weir. The effective length of the weir in SWMM 5 is: L = Original Length - Number of End Contractions * Head over the Weir.

What is suppressed weir?

A measuring weir having its sides flush with the sides of the channel, so that there are no end contractions.

What is a slough gate?

A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway and can be considered as a bottom opening in a wall. Sluice gates are one of the most common hydraulic structures in controlling flow rate and water level in open channels such as rivers and canals.

What is silt excluder and silt ejector?

As, Silt excluders remove silt from the water before it enters the canal and silt ejectors extract the silt from the canal water after the silted water has travelled a certain distance in the off-take canal.

What is Sluiceway in dam?

noun An artificial passage or channel into which water is let by a sluice; hence, any small artificial channel for running water. noun The opening in a splash-dam through which logs pass.

What is overflow rate?

Overflow rate is an empirical parameter describing the settling characteristics of solids in a specific wastewater. Overflow rate is defined as the volume of water flow per unit of time divided by the surface area of the settling basin. It is usually expressed as a velocity in feet per second.

What is the height of weir?

The height of the weir from the bottom of the channel to the crest should be at least 2 times the maximum expected head of liquid above the crest. This is necessary to lower the velocity of approach. The weir height should never be less than 1 foot (0.3 m).

What is weir overflow rate?

Weir loading, also known as weir overflow rate, is the number of gallons of water passing over a foot of weir per day. The standard weir overflow rate is 10,000 to 14,000 gpd/ft and should be less than 20,000 gpd/ft.

What is under sluice in weir?

The under sluices are the openings provided at the base of the weir or barrage. These openings are provided with adjustable gates. Normally, the gates are kept closed. The crest of the under-under sluice portion of the weir is kept at a lower level (1 1.5 m) than the crest of the normal portion of the weir.

What is silt pocket?

a pocket on the underside of a garment, reached through a vertical opening. Collins English Dictionary.

What is afflux in bridge?

Afflux is defined as the increase in upstream water depth as a result of constriction of a flow channel. Prior to the. placement of a bridge across a watercourse, the water surface for a given flood discharge may be assumed a normal.