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INTERBGENCY ECOLOGICAL STUTlY PROeRAN FOR THE SACRAMENTO-SA??JOAQUIN 

### ESTUARY

DELTA FISH FACILITIES TECHNICAL COORDINATING COMMITTEE

WORKING JUSTIFICATION PAPER NO. 2

"Justification For Eliminating From Further Consideration The Horizontal Rotary Drum Screen For The Peripheral Canal"

August 1979JUSTIFICATION FOR 

### ELIMINATING FROM FURTHER CONSIDERATION THE HORIZONTAL ROTARY DRUM SCREEN FOR TISE PERIPHERAL CAN&/

This is a %orking justification paper" that presents the rationale for thepresent direction of the Delta Fish Facilities Program, 

### It was prepared by the Delta Fish Facilities Technical Coordinating Comaittee whose members include both biological and engineering staff of the Interagency Ecological Study Program for the Sacramento-San Joaquirn Estuary,. As a "working" document it is subject tochange based on new fhdings, policy redirection, time, financialand other constraints.
This paper recomiends that further work on conventional horizontal rotary drum screens be eliminated from the program, This decision isbased on a literature review and the results of evaluations of two existing horizontal rotary drum screen installations, the GlennCofusa IrrigationDistrict fish screen near Hamilton City and the Woodbridge IrrigationDistrict fish screen near Woodbridge, California*

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### - I/ Prepared by the Delta Fish Facilities Technical Coordinating ComExittee, part of the Interagency Ecological Study Program for the Sacramento-San Joaquin Estuarywhose members *include: California Eepartrnent of Fish and Game, California Department of Water Resources, U. 

### s. Bureau of Reclamation, and U. 

### s, Fish and Wildlife Service.-2-

DISCUSSION

The horizontal rotary drum screenhas been under consideration for the inzake of the Peripheral Canal. Originally developed in 

### 1921 By the Oregcn Garne Commission it has seen considerableuse throughaut the West, Clay 

### (1961) summarizes some basic information and applications for this screen concept,
The. horizontal rotary drum screenhas proven a reliable device for screening fish once certainbasic criteria have been met. These criteria include a relatively constantwater surface elevationwhich $eaves the upper half to one-third of the drum height exposed, appropriate mesh size eo prevent the loss of fish, and effective seals at the bottom and sides of the drum screen (Figure 

### 1).

Our evaluations have indicated that a solution to the second criterion is available, while a solution to the third could be developed wirhin existing time, financial, and technological constraints. However, the difficulty and cost of satisfying the first criterion listed limits the applicability of the horizontal drum and makes it less desirable than fixed screen or avertical drum screen.
The water surface of the SacramentoRiver at Hood vazies from about 8 to i-6m (0 to +20 ft) USC and GS Datum,with the screenbase 

### located at -5 rn (-16 ft). Unless protected by floodgates, a drum screen wor;'Hd be subjected to the full range of water surfacevariations. 

### To satisfy the first criterion, 2:he drum screen could either 

### be on the order of 

### 15 m (50 ft) in diameter,move up and downwith river stage, ox the water levelwould have to be controlledwith floodgates in front of the screen. The difficulty of designing, constructing, and malneaining a drum screen approximately 15 m (50 ft) in diameter eliEinates this alternative. The difficulty and anticigated cost of developing, constructing, 2nd operating a "floatable horizontal drsx screen alsomakes it 

### less desirable than a fixed screen 

### or a vertical drrrm screen. The operation of floodgates in front of the screen to controlwater level at the screenwould accelerate flow velocities through the control structure, tending to "pull in" toward the screens fishwith limited swiming ability. This would happen with either the on-river or off-riveralternatives,and is undesirable,

A conclusion that horizontal rotary drum screens are inappropriate '~.iras also reachedby John 

### E. Skinner, in his review titled "Peripheral Canal, Fish Facilities Program; 1973-74Evaluations and Decisions," dated August 

### 2, 1974. That document was prepared at the request of the Fish Facilities Consulting Board to document the status 

### of the program at that time,

CONCLUSION

We recommend deleting the horizontal rotary drum screen conce t from further consideration for the Peripheral Canal, based primari

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I, (1) the size-related problems of a horfzontal rotary drum screen, (2) the difficulty and high cost of developing and operating a ‘‘floatabfe”horizontal rotary drum screen, and (3) the undesirability of controlling ehewater surface elevation at the fish screen wit11 a floodgate structure constructed in front of the fish screen, or at the inzake of an off-river channel.-4-



### LITERATURE CITED

clay, C. H. 2.961, Design of fishways and other fish facilities. Queen's &inter, Ottawa. 301 pp.

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