How to Install a Weir Box

While Weir Boxes eliminate many of the typical installation considerations of Weir Plates, some considerations have to be taken into account when installing a Weir Box.

Installing the Weir BOX

• The Weir Box must be mounted so that the weir plate is level from front-to-back and from side-to-side.
• The mounting surface of the weir box should be sufficiently consolidated that it will not shift or move out of position due to settlement, frost heave, etc.
• The weir crest must be horizontally level.
• If present, the bevel of the weir crest must be set downstream.
• In earthen channel applications, the channel downstream of the Weir Box should be reinforced / armored so that scour does not occur.  Scouring can lead to the Weir Box shifting out of position.  
  • Water Measurement with Flumes and Weirs (ISBN 90-70754-55-X) provides details of channel reinforcement, however as a rule of thumb protection should extend at least 4 H_max downstream (and not less than 5-feet [1.5 m].