Dredging vs Diking — What’s the Difference?

Dredging

What it is:
Removing sediment from a river or channel to deepen it.

What it’s meant for:

• Navigation and boat access

• Clearing local choke points

• Short-term flow improvements

What it does not do:

• It does not reduce flood volume during freshet

• It does not stop backwater flooding from the Fraser system

• It does not provide reliable protection for extreme events

Reality:
Temporary, expensive, environmentally constrained, and requires continuous repetition.

Diking (Engineered Flood Protection)

What it is:
A purpose-built barrier (earthen dike or flood wall) designed to keep floodwaters out.

What it’s meant for:

• Protecting communities during major flood events

• Managing low-probability, high-consequence risks

• Providing a defined level of flood protection

What it does:

• Blocks floodwater even when rivers are at extreme levels

• Addresses backwater effects

• Is designed, certified, and maintained to standards

Reality:
High upfront cost, but actually reduces flood risk when it matters.

Key Differences at a Glance

Topic Dredging Diking
Purpose Maintenance / navigation Flood protection Duration Short-term Long-term Flood risk reduction Low High Environmental approvals Ongoing, difficult One-time (with maintenance) Cost structure Forever Upfront + maintenance

Bottom line

Dredging manages - sediment.
Diking manages - risk.

They are not interchangeable - and one cannot replace the other.