Hydraulic Structures

• Hydraulic structures


  Used to either regulate or measure flow
• Hydraulic structures


  • Culverts
  • Weirs
  • Spillways
  • Dams
  • Reservoirs
  • Gates
• Weir


  • Concrete or masonry obstruction in the flow path in an open channel
  • Causes an increase in water depth as water flows over
• Greater the flow rate

  Greater the increase in depth of flow
• Weirs


  Used to measure the volumetric rate of water flow, make rivers navigable and prevent flooding

  
• Weir classification based on

  • Opening shape
  • Crest form
  • Effect of the sides on the nappe
• Weirs based on Opening Shape

  • Rectangular
  • Triangular
  • Trapezoidal
• Weirs based on Crest form

  • Sharp crested
  • Broad crested
  • Narrow crested
  • Ogee-shaped
• Weirs based on Effect of Sides on Nappe

  • Contracted weir (with end of contraction)
  • Suppressed weir (without end of contraction)
• Rectangular weir discharge formula

  Q = 2/3 * Cd * L * H^(3/2) / (2g)

  
• Triangular weir discharge formula

  Q = 8/15 * Cd * H^(5/2) * tan(θ/2) / (2g)

  
• Trapezoidal weir discharge formula

  Q = 2/3 * Cd * L * H^(3/2) / (2g) + 8/15 * Cd * H^(5/2) * tan(θ/2) / (2g)

  
• Culverts


  Conduits used for passing water under highways
• Culvert flow regimes


  • Submerged-entrance
  • Free-entrance
• Submerged-entrance culvert types


  • Type 1
  • Type 2
  • Type 3
• Free-entrance culvert types


  • Type 4
  • Type 5
  • Type 6
• Type 3 culvert discharge formula

  Q = Cd * A * sqrt(2gh)
• Spillways


  Structures built for diverting surplus water from a reservoir after it has been filled to maximum capacity
• Spillway types


  • Straight Drop
  • Chute
  • Ogee
  • Shaft
  • Side channel
  • Siphon
  • Labyrinth
• Sluice gates


  Gates that allow water to flow under, can operate as weirs when closed
• Sluice gate types


  • Flap
  • Vertical rising
  • Radial
  • Rising sector
  • Needle
• Force on a rectangular sluice gate

  From continuity equation, Bernoulli's equation, and summing forces in x-direction
• Dams


  Constructed across an open channel to store water upstream, creating a reservoir
• Dam types


  • Embankment (earth fill, rock fill)
  • Concrete (arch, gravity, buttress)
• Reservoirs


  Developed by water being stored by dams
• Reservoir types


  • Storage
  • Flood control
  • Detention
  • Distribution
• Type 1 Culverts


  The outlet is completely submerged
• Type 2 Culverts


  The outlet is not submerged.

  The normal depth is greater than the culvert diameter.
• Type 3 Culverts


  The outlet is not submerged.

  The normal depth is less than the culvert diameter.
• Type 4 Culverts


  Has a mild slope and a low tailwater.

  Critical depth occurs near the exit.
• Type 5 Culverts


  Has a steep slope and a low tailwater.

  Critical depth occurs near the entrance.
• Type 6 Culverts


  Has a mild slope

  The tailwater submerges critical depth