Rowdy Creek Fish Hatchery Interim Steelhead Rearing Project

The RAS module would have a recirculating flow rate of 500 gallons per minute (gpm), and a make-up water flow

rate of 5% (25 gpm) from the Rowdy Creek supply system. The primary recirculation piping would be 6 inch PVC,

with a 2 to 3-inch make-up water connection. The RAS module would have an overall power demand of

approximately 18 to 25 kw and would need to be connected to a reliable emergency power supply. It may be

possible to connect the module to the existing emergency generator.



Two 20-foot culture tanks located in the foot print of 3 of the four Burrows ponds channels, with the dividing walls partially demolished. The culture tanks would be supported by imported structural fill material, with a layer of sand bedding under and around the tank floor and walls. The fourth Burrows pond channel would be modified with dividing walls to house the RAS equipment. Effluent from the tanks would flow via side box and bottom center tank drains through buried pipes to a drum filter for solids removal. The filtered RAS water would then overflow into a moving bed bioreactor (MBBR) chamber for treatment of ammonia products. The RAS water would then enter a pump sump that serves as a reservoir for balancing

recirculated flow and waste flow to drain. Low head horizontal end suction recirculation pumps would then boost

the RAS flow into the top of an adjacent gas management tower. The upper portion of the tower would be a

counter-current air stripper for removal of carbon dioxide. The lower portion of the tower would include an

optional ozone contact chamber and low head oxygenator to restore dissolved oxygen levels to full saturation. The

flow would then pass through a UV sterilizer for pathogen removal (and de-ozonation), prior to returning to the

culture tanks. This design concept minimizes piping and valve requirements and takes advantage of the existing

Burrows pond infrastructure.



This is a high priority project to provide improved rearing conditions for the existing steelhead program at Rowdy Creek Fish Hatchery. The hatchery has experienced high mortalities and poor overall survival rates due to problems with water supply availability, water temperature and quality issues, and outdated fish rearing facilities. The Nation has completed a long-term plan for modernizing the hatchery that will take several years to fully implement. A near term, less costly interim solution is needed to prevent state and federal authorities from closing down the steelhead program.



The interim program will have a production goal of approximately 25,000 steelhead smolts, with a release size target of 6 fish per pound (76 grams/fish). In order to make the best use of limited water supplies and improve rearing conditions, the program will utilize new 20 foot diameter dual drain circular rearing tanks, and will incorporate water reuse technology and may include a chilling system for use during the summer months if funding allows.

Project will improve rearing conditions for steelhead over summer providing better control over water quality during the summer months when stream flows are greatly reduced. The project will also improve instream flows in Rowdy Creek over the summer months as the recirculating aquaculture system should decrease water diverted to steelhead by approximately 87.5%. The current system is a flow through system that generally uses around 200 gallons per minutes. The recirculating aquaculture system will reduce this down to 25 gallons per minute due to the system ability to reuse water.