Temporary Diversion Series #1
Temporary diversion methods such as river diversion or creek bypass are used to redirect water from a stream or river and focus the flow to a designated portion of the river or creek to allow for construction activities to take place in a specific section of the water body. This can be projects such as integrity digs, pipeline installation or associated bank protection. As well, temporary diversion projects can often be deployed during the construction of detention ponds, dams, in-stream grade control structures, utility installation, including maintenance, that require working in waterways.
River diversion or creek bypass methods include temporary diversion channels, pump-arounds, piped or hose diversions, coffer dams, aqua-dams and other similar practices. The primary purpose of all temporary diversions are to provide safe construction access, protect water quality and aquatic life by redirecting upriver or creek flows around an active construction zone.
NCS Fluid Handling Systems Designers and Engineers consider a variety of options when selected and designing a temporary diversion method, which includes factors such as:
- Is a temporary diversion the correct choice for a particular project and will construction of the temporary diversion have greater environmental impact than if the project is constructed without a temporary diversion? ( A short project duration, such as bank erosion repair or pond maintenance, may consider alternative methods)
- Realistic estimation of project duration and time of year during which construction will occur.
- Size of water body, river, stream or creek and the anticipated flow rates during construction.
- Special consideration should be given to large streams with large tributary areas with higher flow rates or season swings of inflow water from rain and snow melt.
- All water quality or aquatic life conditions the waterway and additional protection or water filtration, such as sediment control.
- Surrounding land use, property ownership, and landowners to ensure all permits are in place, noise control is place and traffic management or impact. (for example, in a highly urbanized area with limited access, there may not be adequate space to construct a diversion system)
- Seasonal variations in stream hydrology (baseflow vs. peak flow).
- Amount of redundancy to be factored into design - probability of flood flows exceeding diversion capacity can lead to diversion failure so NCS Designers work with clients to manage and incorporate redundancy and backup pumping to consider variables such as rain events or up stream activity.