Types of Stream Crossings
Now that we know what to keep in mind and what to look for when planning and selecting a stream crossing, we can move to the next decision. Should this be a temporary or permanent crossing?
Permanent Crossings
Crossings which are intended to be left in place to allow for access to the tract with as little impact to water quality as possible.
Temporary Crossings
Crossings that are installed for a short period to allow access to the tract during an operation, and are removed after the operation is complete. Often the types of materials used to construct a temporary crossing are very different from those used to construct a permanent crossing. Logging mats, logs, or brush are common materials used to construct a temporary crossing. Temporary crossings can obstruct or alter channel flow, so it is very important to remember to remove a temporary crossing after it is no longer needed.
After we have decided if this needs to be a permanent or temporary crossing, we can better determine what type of crossing we should build. Let’s take a look at five crossings and the pros and cons for each.
Culvert Crossings
ADVANTAGES
Culverts provide quality, permanent crossing for streams with high banks.
Culverts allow fish passage.
DISADVANTAGES
They are high maintenance and will blow out if not sized properly.
Dirt enters stream during installation.
Low Water Crossings or Fords
ADVANTAGES
Low water crossings are low maintenance, good permanent crossings for loaded trucks under low flow conditions.
Fords are ideal for gently sloping stream banks.
DISADVANTAGES
Low water crossings are NOT recommended for skidder crossings and steep banks.
Crossing becomes impassable during high flow.
Trucks may muddy waters downstream of crossing.
Bridges
ADVANTAGES
Bridges are good for trucking.
Bridges allow fish passage and cause minimal impact to the stream.
Bridges are a good choice for wider streams.
DISADVANTAGES
Bridges are expensive.
Bridges are difficult to install.
Portable Bridges or Mats
ADVATANGES
Portable bridges are good for skidding and occasional trucking activities.
Mats allow fish passage and minimize impact to the stream and water quality.
Some designs are easy to install (skidders).
DISADVANTAGES
Mats are relatively expensive.
Portable bridges have a limited span capacity.
Temporary Fill (Logs)
ADVANTAGES
Temporary fill is inexpensive and convenient.
Temporary fill is good for skidding and possibly trucking.
DISADVANTAGES
Can impede stream flow and may impact stream and water quality.
Sometimes difficult to remove.
Will not allow fish passage.
In this section, we have reviewed best practices for planning and selecting a stream crossing as well as the advantages and disadvantages five types of stream crossings. We’re now ready to take the Forest Roads Quiz by clicking on the title in the box below.