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1 1.3.5.2 Plate Characteristics. This h'Pe of plate screen consists of a horizontal or vertical traveling screen. The vertical traveling screen contains a continuous belt of flexible screen mesh or separate small framed screen panels (baskets) connected to a continuous sprocket-drive chains on each side of the main screen frame (Figure 1-5). They were first designed to exclude debris from water intakes but were found to be effective in fish passage around turbine intakes. Most applications are electric powered. This type of screen can accommodate large forebay water surface fluctuations while maintaining desired hydraulic conditions for fish guidance. The basket can be used to guide fish to a bypass or for exclusion. The guidance design requires specific modifications to facilitate fish salvage. Typical Existing Applications. The vertical traveling screen is most commonly used for applications where the intake channel is relatively deep. These screens are commonly used for diversions of approximately 100 to 500 cfs or more. Traveling screens have been used in the hydroelectric penstock intakes (Lower Monumental Dam) to screen only the top portion of the intake where juvenile salmon movement occurs. Typical Advantages • Applicable to deep water submerged use • Generally fish friendly • High fish exclusion efficiency for target species and life stages Typical Disadvantages • Not recommended for fish that are easily injured • Expensive to construct, install, operate, and maintain due to the many moving parts; especially when submerged • Metal components wear under use and require high maintenance, newer materials (plastics) may reduce this cost but are untested in the field • Requires costly ongoing maintenance of seals and gap tolerances between baskets • • Does not work well under ice conditions unless submerged, enclosed, or heated Fish passage may occur through faulty or worn seals or areas not screened • Redundancy, fixed screen inserts or blockouts required for maintenance • • Not designed to screen out small life stages Small life forms can ass seals p Application to Limiting Downstream Passage. Has many of the same limitations as drum screens letely submerged condition e of use in a com for downstream but with the advanta assa e use . p g p g , 1 Control Structure Feasibility Evaluation Miller Ecological Consultants, Inc., February 18, 1997 1-15