Specifications include, but are not limited to: This project is intended to protect the upstream ditch banks, ditch bed, and water control structure at Hovland WMA from beaver activity and continuing damage by beavers. It will help prevent beavers from blocking the outlet so that water levels will be maintained at the authorized elevation. Additional Project Specifications: a. Removal of beaver debris and sediment from upstream of the water control structure by an experienced operator. i. Salvaged material may be used to fill beaver-excavated depressions in the ditch bed and bolster the toe of ditch banks, if suitable per the Project Supervisor. ii. In the event additional fill material is needed, the ditch spoil pile (top of west bank) may be utilized at the request of the Project Supervisor. b. Placement of erosion-control fabric across the level ditch bed and re-sloped areas at the toe of each bank. c. Install crushed aggregate bed to a depth of six (6) inches over the fabric on the ditch bed. d. Pack aggregate bed to prepare for installation of precast concrete planks. e. Arrange seven (7) concrete planks on the ditch bottom i. Arrangement may vary from the diagram dependent on the actual width of the ditch bottom. DNR Project Supervisor will direct the placement of all planks. ii. Surface elevation of the installed planks must be installed flush with the footing of the concrete water control structure (per 1269.75 NAVD88). f. Install Class III rip rap on the ditch banks upstream of the structure. i. Disturbed topsoil and ruts shall be leveled by the Contractor. Disturbed areas will be seeded by DNR staff. g. Please see table, below, for estimated quantities of materials and construction notes.
