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Constructing Roads, Landings and Quarries

The following section summarizes the recommended best management practices for constructing roads, landings and quarries. As these are only brief summaries, you should also check out more detailed information in the Karst Management Handbook for British Columbia.

Low Vulnerability Areas

The following best management practices are recommended:

  • Conduct safety briefings for appropriate personnel.
  • Flag karst features and/or values within the operating area.
  • Notify the Forest Service district office if landslides or other disturbances occur which could affect karst features.
  • Modify or cease operations if previously unidentified karst features or values are encountered during road, landing or quarry construction, and notify the Forest Service district office.
  • Avoid construction activities during periods of heavy rainfall.
  • Avoid importing ballast from non-karst terrain.
  • Stabilize disturbed areas, such as quarries, to reduce erosion potential.
  • When constructing temporary access structures, avoid karst features, maintain surface drainage patterns, and minimize runoff and erosion.

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Moderate Vulnerability Areas

In addition to the recommendations for low vulnerability areas, the following best management practices are recommended on moderate vulnerability areas:

  • Directionally fall and yard right-of-way trees away from roadside karst features.
  • Pile surplus construction material away from surface karst features, exposed epikarst, and streams leading into features.
  • Avoid drilling or blasting near karst features, or if this is not possible, use mitigative strategies such as delayed charges, blasting mats, etc.
  • Use overlanding road construction methods near roadside karst features.
  • Avoid fueling or servicing machinery near surface karst features and cave entrances.
  • Keep the wheels or tracks of equipment at least 5 metres from the edge of roadside karst features. If not possible, keep wheels or tracks parallel to the edge of features.
  • Avoid removing gravel or fill from roadside depression features.
  • Minimize clearing of roadside vegetation.
  • Use sediment traps and vegetated infiltration areas to prevent road runoff entering exposed epikarst, surface karst features, cave entrances or sinking streams.
  • Complete construction activities so that cut and fill slopes have time to revegetate before the wetter months of the year.
  • Reduce road runoff by leaving roads on exposed carbonate bedrock unsealed. Use geotextile materials if sedimentation of groundwater is a potential hazard.
  • Crown the surface of sealed roads to facilitate lateral diffuse drainage.
  • Direct runoff from bridge decks away from stream channels and into vegetated cover along stream banks.
  • Minimize potential sedimentation problems by using geotextile materials on bridge decks and around bridge ends.
  • Avoid the use of chemically treated wood for bridges.

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High Vulnerability Areas

In addition to the recommendations for low and moderate vulnerability areas, the following best management practices are recommended on high vulnerability areas:

  • Exposed, well-developed epikarst should only be crossed by relatively short segments of temporary road that can be readily rehabilitated. Consider the following specialized road construction techniques:
    • Use overlanding road construction methods as much as possible.
    • Avoid or minimize grubbing; flush cut stumps, and avoid pulling stumps.
    • Minimize clearing widths, road widths and landing surface areas.
    • Use the largest possible ballast material to build up roads, to span or infill epikarst cavities, and to minimize runoff from the road surface.
    • Avoid using fine materials for road building.
    • Roadside ditches are generally not necessary since runoff percolates directly into the bedrock.
    • Obtain ballast material from nearby low or moderate vulnerability areas.
    • Use geotextile materials to minimize sediment transfer into subsurface drainage systems.
    • Consider the use of geogrids for spanning epikarst cavities.
    • Consider using bridging mechanisms to raise or span roads over short sections of significant epikarst features.
  • Where practical, use rock drilling/hammering instead of blasting on well-developed epikarst. Where blasting is used, seek the advice of a qualified professional.
  • Post public warning signs and close areas while blasting near surface karst features or caves that may be used for recreation.

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