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Which is the type of weir?
Parabolic Weir
Gravity Weir
Vertical Drop Weir
all of the above
all of the above
A weir is a hydraulic structure built across an open channel to measure flow, control water levels, or facilitate discharge. Weirs are classified based on their shape (Parabolic), structural design (Gravity), or operational profile (Vertical Drop), making all listed types valid.
A weir is a hydraulic structure built across an open channel to measure flow, control water levels, or facilitate discharge. Weirs are classified based on their shape (Parabolic), structural design (Gravity), or operational profile (Vertical Drop), making all listed types valid.
Q=CdтАЛтЛЕLтЛЕHn тАФ General discharge equation for a rectangular weir
Q=158тАЛCdтАЛтЛЕtan(2╬╕тАЛ)тЛЕ2gтАЛтЛЕH5/2 тАФ Discharge for a triangular V-notch weir
A weir works by forcing water to flow over a crest, creating a head-discharge relationship governed by the geometry of the notch. For a weir, the discharge Q is typically expressed as Q=CdтАЛтЛЕLтЛЕHn, where CdтАЛ is the coefficient of discharge, L is the length, and H is the head of water above the crest.
Gravity weirs rely on their own self-weight for stability against hydrostatic pressure.
Parabolic weirs provide a linear relationship between discharge and head, useful for proportional flow control.
Vertical drop weirs are designed to dissipate energy effectively in downstream reaches.
Classification depends on purpose: flow measurement, irrigation diversion, or water level regulation.
Parabolic weirs allow for constant sensitivity across various heads.
Gravity structures offer high durability and robustness against erosion.
Weirs can cause sediment accumulation upstream.
Potential for high maintenance requirements at the crest due to cavitation or abrasive debris.
Irrigation canal discharge measurement.
River water level control for diversion structures.
Flood control in small drainage channels.
The choice of weir type is highly dependent on site-specific hydraulic conditions such as sediment load, channel slope, and required precision.
Option C, the Vertical Drop weir, is a classic Sarda type design commonly used in India for canal falls.
D is correct тАФ Parabolic, gravity, and vertical drop weirs are all recognized categories of weirs used in hydraulic engineering based on their geometry and structural stability.
Always remember that in Civil Engineering classification questions, if multiple valid technical types are presented, 'all of the above' is frequently the intended answer reflecting design variety.