Cook Lake Spillway Reconstruction

On July 8, 2019, Cook Lake Recreation Area on Bearlodge Ranger District closed to the public for spillway reconstruction. The project includes demolition of the existing spillway and construction of a new spillway, embankment, stilling basin, and bridge. Cook Lake Recreation Area is expected to reopen in November 2019.

This site will provide updates on the project.

September 16, 2019

Dentates and baffle blocks in spillway chute.

Baffles and dentates in spillway chute


Stilling basin with forms removed from walls.

Stilling basin with forms removed


August 29, 2019

Placing concrete into the wall forms.

Image of concrete being placed into wall forms


Spillway formwork done and braced, ready for concrete.

Image of formwork for spillway walls


August 15, 2019

Spillway slab placement nearly completed.

Image of workers placing concrete for new spillway slab


Formwork for the mud slab over the sand/gravel filter drain.

Gravel formwork for spillway slab


Cleaning out the stilling basin footprint.

Image of heavy equipment cleaning out the spillway stilling basin


August 9, 2019

Lake drawdown was completed on August 8. 

Image of drained lake and cattails, 8/9/2019


July 30, 2019

The lake level has dropped significantly.

Cook Lake Update


Three of the four culverts have been removed and excavation for the new spillway floor has begun.

Cook Lake Update


July 18, 2019

Pumps are draining the lake. Recent rain has slowed this process.

Pumps draining the lake


The embankment below the culverts has been removed.

embankment below culverts removed


July 11, 2019

U.S. Bureau of Reclamation workers are staging equipment and preparing to draw down the lake prior to spillway demolition.

Cook Lake Spillway Reconstruction


The log mat that dissipated outflow below the culverts has been removed.

Cook Lake Spillway Reconstruction