Types of flooding
What is Groundwater Flooding?
Many areas in Blaine County experience groundwater flooding. The porous soils allow water to easily move to the surface. A significant amount of rain in the fall can sometimes lead to groundwater flooding the following spring.
Groundwater flooding is very slow to arrive and leave. People typically have time to move items to higher ground when groundwater flooding occurs.
What is Surface water flooding?
Pluvial (Surface Water) Flooding is caused when the ground is over-saturated and/or drainage systems are overflowed and the excess water cannot be absorbed or drained away.
Pluvial Flooding can be caused by sustained rain or quick, rapid snow melt that cannot be absorbed fast enough.
Curious about how surface water may impact your neighborhood? View the Big Wood River Inundation mapping HERE.
What is Stream Channel Migration?
Channel migration is the natural process that describes how a stream or river channel moves over time. Channel migration can occur gradually, such as when a stream erodes away one bank and deposits sediment along the opposite side. It can also occur quite quickly during floods or high water events. While channel migration provides important habitats and natural diversity, this process can also damage or destroy homes and infrastructure located within these ever-changing zones. Healthy, intact riparian buffers play a key role in combating severe bank erosion.
For existing communities near rivers and streams, it is important to know where channel migration zones exist and plan accordingly. Communities can manage these higher risk areas by guiding development away from channel migration zones. This strategy helps reduce flood and erosion hazards and costly repairs while preventing the loss of crucial floodplain habitat.