Illinois Administrative Code › Title 17 - CONSERVATION › Part 3702 - CONSTRUCTION AND MAINTENANCE OF DAMS › Section 3702.50 - Requirements for Approval of Permits for Removal of Dams

Current through Register Vol. 48, No. 28, July 12, 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.