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IRRIGATION CONVEYANCE SYSTEM TREATMENT GUIDELINES |
A limited number of products are registered or allowed for use in flowing water systems, particularly within
agricultural irrigation waters. Acrolein and xylene, available on a restricted basis, pose severe environmental
and safety concerns. A number of products have been proven impractical since they impose extended water use
restrictions or act too slowly in killing target aquatic vegetation. The ideal product(s) must pose limited risk
to the applicator and the environment, have no restrictions on use of the water for irrigation and quickly control
the vegetation present.
Cutrine-Plus and Clearigate meet these criteria as an effective algaecide and algaecide/aquatic herbicide,
respectively, for use in irrigation conveyance systems. These chemical technologies from Applied Biochemists are
proven cost-effective alternatives to copper sulfate, xylene and acrolein.
Both products contain chelated copper as their active ingredients. Unlike copper sulfate, the copper remains in
solution under a wide variety of water quality conditions. This extended contact time of the soluble copper provides
more complete and extended control of algae. In the case of Clearigate, a patented emulsification/adjuvant system within
the formulation makes the copper readily available for uptake by submersed and floating aquatic plants. This results
in a rapid weakening and death of these vascular plants. Extended downstream control plus reduced application frequency
can be expected from both formulations, as compared to use of old technologies. Algae typically dies and decays within
24 - 48 hours post-treatment. Rooted plants go through a process of knockdown, decay and disappearance during a 2 - 10 day
period.
Both products are registered with the U. S. Environmental Protection Agency and with the State Departments of Agriculture.
International registration and use is prevalent throughout the world. The labeled use for both products allows up to 1.0 ppm
copper in the treated water following product application. This is consistent with the Federal U.S. copper tolerance level of
1.0 ppm copper established for drinking water (CFR Title 21, Part 193.90) and the exemption from the requirement of a tolerance
in eggs, fish, meat, milk, irrigated crops and shellfish (CFR Title 40, Part 180.1021).
Cutrine-Plus and Clearigate are virtually non-corrosive to application equipment. They can be applied through a variety of
delivery systems. Neither product imposes water use restrictions for drinking, swimming, fishing, irrigating or domestic use
during or following treatment.
Effective treatment of flowing water systems is dependent upon: 1) copper concentration, 2) contact time, 3) degree of infestation,
4) type of growth present, 5) water conditions, and 6) weather conditions (e.g. sunlight).
Experience has proven that control can be achieved in flowing water by treating with higher dosages (up to 1 ppm copper)
for shorter contact periods (6 hours or less) or lower dosages (down to 0.2 ppm copper) for longer contact periods (24 hours or more).
Therefore dosage and duration selections must be made to provide a suitable treatment. Dosages less than the maximum rate of
1 qt/cfs/hr for Cutrine-Plus or 2.8 qt/cfs/hr for Clearigate can be used when extended contact time is maintained due to slower
water turnover rates. Use of lower dosage rates should only be considered when water temperatures are above 60°F, optimum weather
conditions prevail and the vegetation infestation is light to moderate.
Frequency of treatments required will vary from system to system depending upon weather, length of season, water quality, type of
growth present and bank/bottom construction. An effective treatment should maintain control for 3 - 6 weeks. Initial treatment
should be made at the first visible signs of growth or when flow restriction first becomes apparent. Ideally water temperatures
should be at or above 60°F.
Drippers or metering pumps are utilized to properly feed product into the flowing water at a rate proportionate to water flow such
that chemical concentration remains constant for the duration of treatment. Drippers are simple, valve-regulated pipes, which provide
a constant head pressure in the chemical tank via a vent tube. Output is depended upon pipe size. Twelve-volt metering pumps provide
a simple method of adjusting output rates. They can be equipped with flow devices, which automatically adjust chemical output to stream
flow. Specifications for this equipment are available though Applied Biochemists.
The following Drip/Metering System Calculation, Calibration & Worksheet instructions are based upon using labeled dosage rates for
Cutrine-Plus and Clearigate. Any reduction in dosage rate should take into consideration the previously mentioned factors. Good judgement,
experimentation and experience will assist in optimizing a cost-effective treatment program.
Download: Drip System, Calibration & Worksheet
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