Stream Crossings

Unit 1: Welcome To Stream Crossings

Stream crossings are often necessary to complete a logging operation.  Because stream crossings have direct contact with the stream, care should be taken while installing or removing stream crossings so that there is as little impact as possible to the streambed and water quality.
The first thing you should decide when planning your road system and stream crossings is whether or not you actually need to cross any stream.  Here are some questions to ask yourself before you decide that a stream crossing is necessary:

  • Is there access from the backside of the tract?
  • Can I purchase a temporary easement or work out a deal with an adjacent landowner?
  • Can I go around the head of the stream?
  • Is the timber on the other side valuable enough to warrant crossing the stream?

Unit 2: Stream Crossings

Dirt crossings are not recommended and should never used.

Unit 3: Factors to Consider when Planning a Crossing

Once you have decided that a stream crossing is necessary, several important factors will help you determine the appropriate crossing to install.  These factors are:

  • Permanent or temporary crossing
  • Truck or skidder crossing
  • Wet or dry season
  • Stream bank layout / stability
  • Size of the watershed / stream width / depth
  • Impacts to water quality

Taking these considerations into account  before installing a crossing can help you stay productive while minimizing the impact to water quality.

Unit 4: Selecting an Ideal Stream Crossing Location

Selecting the location of a stream crossing is just as important as determining the type of crossing to install. When choosing crossing locations, you should look for the following:

  • Narrow stream sections
  • Straight (not in a curve)
  • Flat ground
  • Low flow
  • Stable banks
  • Good access to tract

Think about how you would evaluate the stream on the left for the above listed factors and then think about how you would cross it.

Unit 5: Permanent Vs Temporary Crossings

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.

Unit 6: Types of Stream Crossings

Unit 7: Culvert Crossings

ADVANTAGES

  • Culverts provide quality, permanent crossing for streams with high banks.
  • Culverts allow fish passage.

DISADVANTAGES

  • Culverts are not ideal for temporary crossings.
  • They are high maintenance and will blow out if not sized properly.
  • Dirt enters stream during installation.

Unit 8: 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.

Unit 9: 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.

Unit 10: Portable Bridges or Mats

ADVANTAGES

  • 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.

Unit 11: 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.

Unit 12 Stream Crossing Quiz

Congratulations!

You have now completed the Stream Crossings Chapter. You may now begin the Quiz for this section. To advance to the next chapter, you must score 80% or greater.