Emplacement and Efficacy Testing of Pulsed Direct Current Electrical Barrier
Methodologies to prevent unwanted entrainment and transport of fish during Reclamation's water delivery and power production operations are usually expensive, labor intensive, and are often site-specific. Remotely operated behavioral barriers (barriers that attempt to elicit a desired response) may be effective at reducing entrainment of various species without impacting water delivery. An electrical barrier system has been available to Reclamation for testing since spring 2006. This Science and Technology (S&T) Program research project seeks to address the following questions:
* Can an electric barrier be cost effective compared to a physical barrier with regard to entrainment prevention?
* What are the preferred diversion characteristics necessary to optimize an electric barrier efficiency?
* How effective is the electric barrier at preventing entrainment once it is installed?
Need and Benefit
Fish entrainment at Reclamation diversions, penstocks or canals has had a direct causal impact on Reclamation's ability to deliver water, make power, or reduce operational costs. These impacts are usually a manifestation of reasonable and prudent alternative delivery strategies associated with the Endangered Species Act (ESA). Thus, technologies that assist with the prevention of entrainment have an intrinsic value to Reclamation.
Generally, entrainment negation consists of physical barriers such as drum screens, weirs, louveres, etc., and these barriers are expensive from fabrication through installation. Maintenance costs of physical barriers can cost many thousands of dollars annually. Alternatively, behavioral barriers (barriers that seek to elicit a desired response) are often nonintrusive to water delivery and are generally operated remotely for long periods of time. Reclamation has limited experience with pulsed direct current electric barriers, although they have been useful at remote field locations and have been shown to be effective in certain situations where they have been applied (Clarkson 2004), though initial purchase costs are considered too prohibitive to evaluate at many small diversions. The Montana Area Office (MAO) has purchased a barrier that is currently undergoing temporary efficacy testing in St. Mary, Montana. This barrier will not be installed permanently at this site due to a complete diversion restoration and engineering revamp.
This represents a large cost-saving opportunity (the barrier is already bought and paid for) to test this behavioral barrier technology at an alternative field site. It is critical that the barrier be matched with a diversion or canal where there is both:
* A need for a noninvasive, remotely operated behavioral barrier
* A good "fit" (a location whose morphology and engineering will optimize the electric barrier performance).
A noninvasive fish deterrent system could save several million dollars over conventional physical barriers (over the life of a project) because of lower operation and maintenance costs.
Clarkson, R.W., 2004. Effectiveness of electrical barriers associated with the Central Arizona Project. North American Journal of Fisheries Management volume 24 pages 94-105.
Fisheries and Wildlife Resources, Technical Service Center
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