Checkmate® In-Line Check Valves Used in Sustainable Flood Alleviation Design


The Ballygawley River flows next to St Ciaran’s High School in County Tyrone, Northern Ireland. In 2008 and 2011 there were several flooding events during times of heavy rainfall which severely affected properties next to the river.

Significant work was authorized to greatly reduce the risk of flooding at three locations along the river. This alleviation work provided flood defense to a large secondary school (800 pupils), a nursery school, a church hall, a commercial auto garage and seven residential properties. Various climate change scenarios were modelled during the process and incorporated within the final scheme.


Ultimately, the design team chose to install a 900mm CheckMate® In-Line Check Valve, manufactured by the Red Valve Company, Pittsburgh, PA, USA, as a critical component in the flood alleviation scheme, because of its sustainable drainage control in comparison to a pumped system. Sustainable flood alleviation schemes using CheckMate® and Tideflex® Valves are a low-cost solution for municipalities to address flooding due to increased surface water run-off, as residential areas continue to expand.


The outstanding reliability of the CheckMate® Valve to seal effectively, even in mud, silt and debris, is enabled due to its passive design, which requires no electrical power or generator back-up systems. Because no outside energy source is needed for the CheckMate® Valve to operate, significant cost savings are achieved. In addition, CheckMate® Valves are unaffected by long periods of infrequent use. The hydraulic force of the flood water is captured by the valve, powering it through continual accumulations of mud, silt and rocks while functioning flawlessly.

In addition to Installation of the CheckMate® Valve in the main drainage outlet, additional work of the flood alleviation plan included:

  • Construction of approximately 700 yards of sheet piled flood wall with reinforced concrete capping beam and concrete stem wall.
  • Construction of approximately 280 yards of king post (soldier pile) reinforced concrete.
  • Flood wall construction of approximately 235 yards of reinforced concrete flood wall.
  • Construction of approximately 75 yards of sheet piled flood wall with landscaped earth bank.
  • Construction of approximately 70 yards of concrete flood wall with landscaped earth bank.
  • Installation of back drainage to all flood defense works.
  • Installation of fishery environmental enhancement habitat units.

The project was completed on time and on budget and continues to deliver sustainable value to the community.