A new aquarium and the removal of a crumbling dam are in the works to improve the Issaquah Salmon Hatchery. The public can get a look at the plans Friday night in a special fundraising presentation by Friends of the Issaquah Salmon Hatchery.

The dam, upstream of the hatchery, dates to 1937 and is being replaced with a natural fish ladder made of a series of rock weirs that are being installed in the creek. The $4 million project, approved by the Legislature this year, will make it easier for fish to make it further upstream to spawn.

Tim Ward, Washington Department of Fish and Wildlife project manager and Kerry Ritland, surface water manager for the city of Issaquah, will talk about progress on the dam removal. The old fish ladder, with 12-inch high steps, was too high for the returning fish since they were nearing the end of their lives and running out of energy. Now, each step-up is 9-inches, followed by little pools for the fish to rest before making the next jump. A narrow constriction upstream will provide the right flow to gather the water for the hatchery with less silt.

With the old dam, fish often could not make it past the dam. As the bottom of the dam began to erode, a cement shelf was built, but when the water is low in the fall, many fish would just flop on the slab and die before they could spawn.

Also needing a fix is the hatchery’s aquarium. After 10 years, it failed and no longer could maintain the water quality the fish need, or present a good view of the salmon as they mature. Friends of the Issaquah Salmon Hatchery Executive Director Jane Kuechle said two FISH volunteers agreed to tear out the old aquarium.

In the old tank, the alevin, or baby fish, would be in baskets in the water, which is not natural. The new aquarium, by Aquarium Concepts, will have gravel, rocks and some wood in the bottom, which mirrors the young salmon’s natural habitat.

It’s also crucial for the water in the tank to be cold, Kuechle said. Using chillers and a modern filtering system, the water in the tanks will be maintained at the right temperature for the young salmon.

The exhibit will have two side-by-side tanks to provide a 10-foot by 4-foot viewing window. It also will have a backdrop that will look like Issaquah Creek, which will be painted by Larry Kangas, the same artist who painted the depiction of salmon predators on the hatchery water tank.

Jordan Valente Construction of Issaquah is donating its services to build reinforcement for the tanks and Illuminate Contracting is donating electrical supplies. Total cost for the new aquarium is $20,000, with $5,000 already committed by the FISH board of directors and $2,000 donated by the Issaquah Kiwanis.

While the project still comes up short, Kuechle said it’s important to have the new exhibit up and running when school starts because each year approximately 10,000 children visit the hatchery.

Also, FISH has begun its annual volunteer recruiting. A free volunteer training class will be Saturday, Aug. 24. Visit issaquahfish.org and click on “get involved.” Complete the volunteer application form to join the class.