Riverwatcher

In many cases, these systems are retrofitted into existing fish ascent aids (FAA). When retrofitting a monitoring facility into an existing FAA, several factors must be considered to ensure that the functionality of both the monitoring unit and the FAA are not compromised. The same requirements naturally apply to new FAA constructions. However, in new constructions, these considerations can be incorporated into the early planning stages to ensure the best possible integration and accessibility of the system.

The monitoring unit, while representing an independent passage within the FAA, is not hydraulically to be considered as a slot, as water can also flow around the system. A difference in water level between the beginning and end of the system is expected to be minimal, especially with cleaned trash racks. However, appropriate distances need to be provided between the integrated system in the trash rack structure and the upstream and downstream passages. A distance of approximately 50-60% of the regular trash rack length in the FAA, but at least 1.5 meters, is recommended for the downstream passage. The distance to the upstream passage should be around 70-90% of the regular trash rack length in the FAA to minimize the entry of air bubbles into the system. In the FAA of TIWAG, for example, the camera systems were installed in settling basins; these basins have twice the length of the regular basins. It is also possible to install the system in the upper water of the FAA, above the last basin. A lifting device should be provided for easy cleaning of the system.