Saturday, February 9, 2013

Nursery Tank Face-Lift

Dworshak National Fish Hatchery has 64 fish rearing tanks in their nursery that are getting a new "face lift" this January. These tanks are part of the original infrastructure from when Dworshak was constructed in 1968. Unfortunately, time has taken it's toll on the surfaces inside the tanks. After 45 years of use, the "cream" in the concrete mixture, that was used to build the tanks, has slowly eroded away, exposing the rock aggregate underneath. The aggregate's rough surface is hard on both the newly ponded fish, as well as the fish culturists that are caring for them. Between fish cycles, the tanks are hosed out and disinfected to prevent the spread of any potential fish health diseases from spreading to future fish. The aggregate surface leaves more surface area for bacteria to hide, making the disinfection process more challenging and time consuming.

Local contractors, along with Dworshak personnel teamed up to resurface the fish tanks, in an effort to fortify the concrete and add many more useful years to them. This process required financial funding by the Corp of Engineers, along with a commitment of time and hard work by the contractors and hatchery personnel. The tanks had a concrete resurfacer applied to the rough aggregate surface, followed by a green primer coat of paint, and finally, a gray, two part epoxy paint coating was applied. The tanks are now smooth to the touch, sealed and ready for the young steelhead to be put into them. Thankyou to everybody involved in this process and for seeing that everything ran smoothly and was finished in a timely manner.

40-years of water erosion on the Nursery Tanks

A very rough surface, indeed!

The same tanks after re-surfacing with concrete patch.

The first primer coat of epoxy.

Finished epoxy coating.....ready for the next 40 years!

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