(a) An operator
shall install a culvert on a forest road according to the following standards:
(1) a temporary culvert and the adjacent
roadway must be constructed to pass or withstand the 25-year flood without
damage; a permanent culvert and the adjacent roadway must be constructed to
pass or withstand the 50-year flood without damage; any adjustment to these
design standards must be determined in the field considering the
characteristics of the drainage, the design life of the road, the importance of
downstream resources, the type of construction techniques, and the likelihood
of culvert or road failure;
(2) the
size of the culvert must be determined in accordance with hydrologic
engineering principles; a culvert may not be installed that is smaller than 12
inches in diameter or equivalent capacity; where culvert icing conditions are
to be expected, other drainage designs such as open flumes buried in the road
surface should be considered instead of culverts;
(3) for fish-bearing waters, the entrance, to
the extent possible, and exit of a stream culvert must match the natural course
of a stream channel; a culvert may not be perched at its inlet or
outlet;
(4) a culvert must
terminate on material that will not readily erode, such as riprap, the original
streambed if stable, or other suitable materials;
(5) a change may not be made in the course or
channel of anadromous fish waters catalogued under
AS
16.05.871 without giving notice to the
division and receiving written approval of the Department of Fish and Game; a
change may not be made in the course or channel of other waters that are
significant for protection of downstream water quality, without prior notice to
the division;
(6) when a flume,
downspout, downfall culvert, or similar structure is used to protect fill
slopes or to return water to its natural course, the discharge point shall be
protected from erosion by
(A) reducing the
velocity of the water;
(B) using
rock spillways, riprap, or splash plates; or
(C) using equally effective methods or
structures;
(7) for
nonfish-bearing waters, the area of a stream bed from a culvert inlet to 50
feet upstream from the culvert inlet must be cleared of mobile slash or debris
that may be expected to plug a culvert;
(8) to prevent or minimize sedimentation, the
entrance of a relief culvert must have adequate and appropriate catch basins,
consistent with physical features of the ground; a headwall must be used to
direct ditch water into cross drains;
(9) a culvert must be of sufficient length to
prevent road overlay materials from blocking an end of the culvert.
(b) A properly prepared and
maintained ford may be used for an equipment crossing during a period of low
water. If the ford crosses anadromous fish waters catalogued under
AS
16.05.871, written approval of the Department
of Fish and Game is required. For other surface waters, prior notice to the
division is required. A ford must cross a stream substantially perpendicular to
the stream flow, and the approaches must be properly ballasted or otherwise
stabilized to avoid sedimentation. Ford construction must comply with
AS
16.05.841.
As of Register 166 (July 2003), and acting under
AS
44.62.125(b)(6), the
regulations attorney made technical changes to
11 AAC 95.305(a) (5) and (b), to reflect Executive Order 107 (2003).
Executive Order 107 transferred functions related to protection of fish habitat
in rivers, lakes, and streams from the Department of Fish and Game to the
Department of Natural Resources.
As of Register 186 (July 2008), and acting under
AS
44.62.125(b)(6), the
regulations attorney made technical changes to
11 AAC 95.305(a) (5) and (b), to reflect Executive Order 114 (2008).
Executive Order 114 transferred functions related to protection of fish habitat
in rivers, lakes, and streams from the Department of Natural Resources to the
Department of Fish and Game.
