OAR 141-093-0275: Maintenance Dredging - Specific Conditions

(1) General Conditions Apply. All requirements, procedures and conditions set forth in OAR 141-093-0135 (General Conditions) apply to this General Permit, except as follows: (a) General Condition (8) Pre-construction Resource Area Fencing or Flagging does not apply; and (b) General Condition (9) Erosion Control Methods applies only to maintenance dredging activity involving upland placement of material. (2) Removal-General. (a) To the extent practicable, maintenance dredging activity must be staged from an upland or vessel-mounted position. If necessary to achieve the removal, heavy equipment may be staged on or traverse impervious surfaces in the dry below ordinary high water or highest measured tide. In such case, equipment must use water quality best management practices specified in the DEQ-issued Section 401 Water Quality Certification for the project. (b) For vessel-mounted operations, vessels must not be grounded on the bed or banks at any time. (c) Accumulated woody debris within the maintenance dredging footprint may be removed to the extent necessary to achieve the target bathymetry. (3) Removal by Hydraulic Pipeline Dredge. (a) To the extent practicable and as material characteristics allow, the working end of the dredge ladder must be kept buried at a target depth of at least 24 inches below the bottom of the waterway. The intake may be raised no more than 3 feet above the bed for the minimum time necessary for purging or flushing. No back-flushing of the pipeline is allowed. No jetting of sediment is allowed unless approved by the Department pursuant to OAR 141-093-0260(3). (b)The pipeline and any anchors or floats must be removed from the waterway immediately upon completion of the maintenance dredging activity unless another minimum necessary timeframe is approved by the Department. In no case will the pipeline, anchors, floats or other equipment be permanently placed in waters of this State. (c) Pressure in the dredge pipeline must be continuously monitored during operation. In the event of a sudden and sustained pressure drop, dredging activity shall immediately stop. Any breach of the pipeline must be repaired prior to restarting dredging operation. (4) Removal by Closed Bucket. To the extent material characteristics allow, the bucket must be sealed in the closed position to minimize sediment re-suspension. Moving material on the bottom to consolidate it before lifting is prohibited. (5) Material Transport. For dredged material transported by vessel or other over-water conveyance: (a) All dredged materials must be placed in vessels or other conveyances equipped such that no dredged material discharges to waters of this State during loading, transfer and unloading activity for upland placement. (b) Vessels must be staged such that there is no grounding on the bed or banks at any time. (6) Placement – General. Unless otherwise authorized by the governing regulatory agency or agencies, removed material must not be placed in any wetland, Federal Emergency Management Administration designated floodway, or in an area historically subject to landslides. (7) Upland Placement. (a) Removed material placed in an upland site must meet the Oregon Department of Environmental Quality definition of clean fill or the use must be specifically allowed by the Oregon Department of Environmental Quality by rule, permit, or other authorization. (b) Waste waters from the upland placement site must have adequate settling time before being discharged into a water of this State. Water discharged from the upland placement site must meet water quality requirements of the Oregon Department of Environmental Quality. (8) Flowlane Placement. Flowlane placement must occur on the ebb tide only and only when there is sufficient current to disperse the material to prevent shoaling. (9) Ocean Placement. Ocean placement may only occur as authorized by a USEPA letter of concurrence. (10) Ocean Shore Permit. If the project includes direct placement of material on the ocean shore, a separate Ocean Shore Permit, administered by Oregon Parks and Recreation Department, will be required to authorize that activity. (11) State-Owned Waterways. Maintenance dredging in a state-owned waterway may be subject to a Short-Term Access Agreement with the Department. The placement of state-owned material on uplands is subject to a Sand and Gravel Lease or License from the Department. Any beneficial use of state-owned material may be subject to royalty payments to the Department. (12) Fish Entrainment. The authorization holder must immediately report any fish observed that are entrained by operations to the nearest OR Department of Fish and Wildlife office. The permittee must provide access for OR Department of Fish and Wildlife staff to enter the project site for making fish entrainment observations. (13) Post-Activity Reporting. Within 90 days of maintenance dredging completion, the authorization holder must submit to the Department a scaled drawing illustrating the actual removal area and post-removal depths achieved using the same datum as used in the application. (14) Modifying Conditions. The Department may modify the conditions of the authorization at any time if necessary to reduce or eliminate adverse effects to water resources.