SURE-BEND (Hydraulically Operated Bending Weir)

The SURE-BEND Hydraulically Operated Bending Weir System is designed to maintain maximum water levels upstream of the weir thus allowing full usage of all the available upstream storage volume while not adversely affecting the overflow weir capacity in Combined Sewer Overflow (CSO) applications. The SURE-BEND’s unique and extensively tested design operates by only allowing any excess water in the system to reach the receiving stream but only after the design upstream water level is reached. This increases the tank and sewer storage volume and reduces the frequency and volume of overflow events, resulting in a decrease in water pollution. This allows the SURE-BEND to overcome the fixed weir’s inherent disadvantages. The SURE-BEND protects against backflow as it is normally in the closed position.


The SURE-BEND allows for installation in new overflow structures or can be retrofitted directly over existing fixed weirs. The following components are required and included in the SURE-BEND Hydraulically Operated Bending Weir System: the bending weir flap, the sleeve bearings, the supports, the guide walls, the anchoring system, the hydraulic cylinder, the hydraulic power unit, the control panel, the ultra-sonic water level sensor and the inclinometer.


  • Positive hydraulic control
  • No need for bottom clearance
  • Maximize in-situ storage
  • Easily adjustable operating level
  • Reduce overflow frequency
  • Backflow prevention
  • Improved hydraulic grade line
  • Lower storage tank construction costs owing to smaller tank volumes
  • Easy to retrofit into existing installations
  • Stainless steel construction

Range of Application

The SURE-BEND Hydraulically Operated Bending Weir System can vary from a model GSB-30 to GSB-100. The GSB-30 is designed to hold back 12 inches (30 cm) of water over the weir crest and the GSB-100 holds 40 inches (100 cm) of water over the weir crest. The SURE-BEND’s model selection is based entirely on the height of the storage water required. The units are modular in design with a single unit being up to 20 feet (6 m) long. The hydraulic capacity of the SURE-BEND is at least equal to that of a standard overflow weir.

System Operation

The SURE-BEND hydraulically operated bending weir is installed on the downstream side and directly over the entire length of the overflow weir opening. The SURE-BEND accommodates the overflow by pivoting at the bottom and swinging open from the top.


The SURE-BEND is equipped with a hydraulic operating cylinder(s). The hydraulic cylinder(s) acts against the bending weir flap to adjust the upstream water level to the desired level for all flow conditions. In case of power failure, the SURE-BEND hydraulically operated bending weir is designed to remain fully open and act as an emergency overflow. The upstream and downstream water levels are constantly monitored.