Riggs Engineering - Civil Engineering - Marine Specialists

Our Projects

Colborne, Ont. ‐ Design of a New Lake Outfall

Township of Cramahe, Ontario

Town of Colborne, Ont. - Design of a New Lake Outfall


Riggs Engineering was retained to complete the marine design component of a sewer outfall. The tasks included characterizing the coastal environment, carrying out dispersion modeling and design calculations, marine surveys (soundings, side-scan sonar, and underwater video recording), and the design of an optimum configuration of the outfall diffuser. All field investigations were undertaken using in-house equipment including a Trimble GPS, RESON echo sounder and Imagenex sidescan sonar.


Detailed plans and specifications were prepared for all in-water components of the work. The diffuser design took into consideration concerns related to ice damage and on-going maintenance. A detailed design was undertaken to identify the most appropriate lake bed scour protection, pipe and protective rock placement, and installation of reinforced concrete pipeline anchors.