Current through Register Vol. 48, No. 38, September 20, 2024
a) Dependent upon the size, height, reservoir
impounding capacity, upstream and downstream channel conditions, existing
reservoir sediment deposits, degree of hazard in case of failure, as well as
any other considerations which might be peculiar to a particular dam, the
following OWR requirements shall be met unless the applicant establishes that
one or more specific requirements for a permit to remove a dam are not
applicable.
b) A reasonable method
to accomplish the following requirements will be accepted. It is strongly
recommended that applicants contact OWR prior to initiation of studies and at
any time during the development of the permit application if questions should
arise.
1) Reservoir Dewatering - The
reservoir shall be dewatered with a method and timing such that the downstream
channel shall not overflow to a degree to cause damage.
2) Effecting Breach - A breach shall be made
in such a manner as to be safe under all reasonably anticipated storm
events.
3) Size of Breach - The
waterway cross sectional area of the final breach shall be sufficient to at
least pass the 100-year frequency flood with negligible backwater
effect.
4) Control of Erosion at
Site of Breach During and After Breaching Operations - Erosion of the dam
embankment and adjacent area shall be controlled during and after breaching
operations by proper breach procedure, use of appropriate structural measures,
and necessary maintenance measures thereafter.
5) Downstream Channel Impacts - Effects of
the breach on the downstream channel shall be assessed. Increases in water
levels downstream of the breach over that which occurred prior to construction
of the dam shall be negligible unless the owner can show that no damage results
from such increases. If increases in water levels are not negligible or if
damage can result from the breach, OWR will require the owner to mitigate such
damages.
6) Restoration of Original
Channel Upstream of Breach - The original channel shall be restored, or an
alternate channel shall be required to provide flows approximating the original
flow regime (restoration to the extent possible, of the channel and stream
flows to original conditions prior to construction of the dam) through the bed
of the reservoir from the breach to the upstream end of the area impacted by
the reservoir.
7) Control of
Sediment Deposits in Reservoir - Measures shall be undertaken to minimize
movement of reservoir sediment deposits through the breach.
8) Restoration of Reservoir Lake Bed - The
bed of the reservoir within the 100-year flood plain shall be restored to a
condition whereby it can serve a reasonable flood plain use.
9) Plan for Maintenance - A plan for
providing regular maintenance of the breach, outlet channel, inlet channel, and
reservoir bed will be required by OWR, for the period of time necessary to
establish plant cover or other erosion and sedimentation control.
