9 CFS Modular Design
A number of operational issues made this project one of FCA’s most valuable in terms of knowledge gained.
The lessons learned from this project have shaped not only the process for development, but also helped to refine the technology itself.
The German Gulch project began with a site visit in June of 2007 to evaluate the potential to use a Farmers Screen. In October of 2008, a modular Farmers Screen was installed on the diversion. This screen was installed in the fall, when stream flows were relatively low. Therefore, there wasn’t enough water in the stream to fully test the screen at the maximum flow until the spring. However, even at lower flows, problems with water surface elevations at the point of diversion were apparent. Other issues were realized in the spring when the screen was taking maximum flow. In 2011, FCA and Montana Fish Wildlife and Parks welcomed support from Trout Unlimited, and together the three entities were able to create the needed solutions to the problems encountered at the site, including:
- Screen was re-installed at a lower depth (screen elevation was dropped by 6” by re-installing the entire structure)
- Concrete walls at the head gate were raised to allow for greater head requirement
- An additional screen section was added to accommodate the higher flow range
- A new, longer flume was added to provide better entrance hydraulics
- A series of hydraulic adjustments and modifications were made to the screen to create more uniform approach velocities
- The screen was monitored throughout the irrigation season
FCA is happy to report that through the collaborative process the issues at this site have been successfully addressed. The German Gulch Farmers Screen is now working as intended and is considered to be a success.