Christchurch Polytechnic Institute of Technology Campus Drainage Assessment

Christchurch Polytechnic Institute of Technology Campus Drainage Assessment

CGW worked with PACE Project Management to undertake the assessment of approx. $7M worth of drainage infrastructure for insurance purposes post Canterbury Earthquake sequence. This project involved the coordination of survey work both above and below ground, reviewing of a significant amount of CTV footage and detailed locating and mapping of services to assist CPIT to understand the extent of damage

Orphanage Creek Culvert Upgrade

Orphanage Creek Culvert Upgrade




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Asset Value:


The objective of the project was to increase the culvert capacity for Orphanage Creek and provide a cycleway underpass below Main Road Stoke. CGW provided the hydrologic and hydraulic assessment, inlet spillway and culvert civil and structural design, and construction monitoring.

Consideration was required of the aesthetic and ecological values of the pond in a Council reserve immediately upstream of the culvert, and how the proposed design would maintain these values. Very tight vertical height limitations posed conflicting priorities between culvert capacity and maintaining a usable cycleway underpass.

An elegant solution utilises the existing culvert for low to medium flows and provides an aesthetically pleasing long weir along the pond edge into the new cycleway culvert to provide the extra capacity needed during high flows without excessively raising pond water levels. This resulted in a win-win-win solution for the environmental, hydraulic and cycleway requirements of the project.