Experience with the design and operation of a 10-m³/sec marine filter intake

Conclusions

• 1. Construction of the filter intake described in this article permits solving satisfactorily the problem of preventing the passage of fish toward the trashracks of pumping stations. The effectiveness of the filter fill depends not only on the absence of a direct path for the fish between the sea and the canal, but probably also on the formation of surfs near the fill, which scare the fish away from the intake.

• 2. The filter intake considerably reduces the penetration of suspended sediments into the water-supply system and completely prevents the penetration of deposited sediments. It also reduced considerably the penetration of algae.

• 3. In order to increase the effectiveness of the operation of the filter intake here described, it is evidently convenient to place additional concrete cubes at those locations where through passages are found, and to place large stones on the inner faces of such portions of the levees. This work should be carried out only after additional data on the operation of the structures have been gathered.

• 4. The favorable results obtained with the operation of a marine filter intake using levees permit recommending such a solution not only for new intakes, but also for existing marine intakes protected by levees and having an open passage between the sea and the headrace canal. It would be desirable to have an opinion on this matter of specialists in charge of such intakes. It must be pointed out that in the case of an insufficient filtering capacity of the inlet at existing canal intakes, the filtering front at the head of the intake may be developed further. Such a stituation may arise only when the water consumption exceeds 10–15 m³/sec.

• 5. It is convenient to permit the use of local stone having lower technical specifications for the levees. and to omit the construction of special bases under the fills when the foundation bed consists of dense soils, in order to reduce the cost of these structures.