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Indiana Department of Natural Resources

Forestry > Forestry BMP's > Stream Crossings Stream Crossings

Avoid crossing streams when possible. 

General Guidelines:

  • Cross at right angles at a point where the stream bed is straight and uniform.
  • Minimize the use of equipment in the stream bed.
  • Limit construction activity to periods of low or normal flow.
  • Avoid prolonged activity in salmon streams during spawning periods (March 15-June 15 and July 15-Nov. 30).
  • Minimize excavation and fill at stream crossings and other disturbances to stream banks and channels.
  • Use materials that are clean, non-erodible and non-toxic.
  • Avoid using soil as fill except when installing culverts.
  • Avoid altering stream flow.
  • Divert runoff from roads and trails leading to stream crossings into undisturbed vegetation. Avoid directing runoff directly into streams, including ephemeral streams.
  • Construct bridge, culvert, or pole crossing at elevations higher than their road approach.
  • If necessary, stabilize road and trail approaches to stream crossings with aggregate or other suitable material.
  • Anchor one corner of bridge to prevent movement down stream.
  • Stabilize exposed soil as soon as practicable.
  • Maintain crossings in safe, functional condition.
  • Close temporary crossings by removing culverts, poles, portable bridges and other obstructions as soon as crossings are no longer needed.

Bridges

General Guidelines:

  • Bridges are effective ways to keep equipment out of flowing streams.
  • Utilize a bridge design that will provide safe access and minimize disturbance to the stream bank, channel, and the riparian management zone.
  • Use temporary or portable bridges instead of culverts to access areas where permanent structures are not needed.
  • Place them so as not to unduly constrict stream channels or impede flood waters.
  • Anchor temporary bridges on one end with a cable or other device so they do not float away during high water.
  • Install so they can be removed easily and promptly when they are no longer necessary.
  • Portable bridges may be rented through the Indiana Division of Forestry. For more information, contact Jeff Settle at jsettle@DNR.in.gov or call 812-358-2160.

Culverts

Consider using a permanent rather than a temporary culvert when the crossing is likely to be used again within 10 years. Avoid use if temporary or portable bridges are more suitable.

General Guidelines:

  • Use minimum size of 12 inches in diameter and large enough to pass flood flows. See Culvert Size Guidelines.
  • Use arch culverts where it is important to retain the natural stream bottom.
  • Both ends should extend at least one foot beyond the edge of the fill material.
  • Place in line with the natural stream course.
  • Install at or slightly less than the natural stream slope.
  • Compact fill material firmly around culverts, particularly around the bottom half to prevent water from seeping around the culvert.
  • Cover the top of culverts with fill to a depth of 1/3 the pipe diameter or at least 12 inches, whichever is greater, to prevent crushing.
  • Hollow logs are permissible in very small channels if they can handle anticipated stream flows but should be removed once they are no longer needed.
  • Keep culvert open and free of obstructions.
  • Use flared-end culverts or rip rap where necessary to protect culvert inlet from erosion.

Fords

Avoid using fords if practicable, especially in areas of high water quality concerns.

General Guidelines:

  • Select fording sites with gentle approaches, low banks, and hard, stable streambeds.
  • Construct to conform as closely as possible to the original streambed to minimize water flow restrictions.
  • Stabilize the streambed and approaches where necessary.
  • Stabilizing material may include: corduroy mats, reinforced concrete planks, crushed rock, rip-rap or rubber mats.
  • Avoid depositing soil in the stream during ford construction and use.
  • Avoid use during high water.
  • Pole fords should be used carefully to maintain water flow.
  • Pole fords are not appropriate for perennial stream crossings.
  • Remove pole fords immediately after use.