Construct Coffer Dams as required to protect sites during the work. Install, maintain, and remove temporary coffer dams to facilitate removal of abutments and piers while not blocking more than half of the stream channel at any time. Selectively saw-cut and remove reinforced concrete pier walls, sill walls, structural and miscellaneous metalwork, timber planking, and miscellaneous hardware. Existing concrete buried cut-off walls and slab to remain as a permanent feature at the Lower Weir. All features shall be removed at the Upper Weir. Excavate and remove existing reinforced concrete abutments (4 total, 2 each at the Upper and Lower weirs). Place soil backfill in excavated areas at each abutment site. Recycle, reuse, salvage, or dispose of all waste materials removed at permitted sites. Restore disturbed soil areas, primarily at the abutments but potentially other locations around the weirs. Install erosion control measures as required by permits to prevent loss of soil materials. Place seeding mix, saplings, and other items (irrigation, etc.) to initiate re-vegetation efforts.