Tetra Tech INCA prepared engineering studies and plans, specifications and estimates to stabilize the portion of the right dam abutment that supports the pedestrian access bridge to the air vent shaft at Mud Mountain Dam.

In conjunction with the slope stabilization and grading work, INCA designed new domestic water, fire supply, and intake tower flushing water systems to replace existing services demolished during new construction. This work included the preparation of plans and specifications for three new 50,000-gallon water tanks, three new pipelines, thrust restraint systems, air release/vacuum valves, and appurtenances.

INCA surveyors provided mapping for stability correction design showing existing slope conditions and planimetric features. All work was tied to the Mud Mountain Dam horizontal and vertical control network.