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Nuisance Aquatic Plant Control in Water Delivery Systems

Project ID: 6688
Principal Investigator: Dale Lindeman
Research Topic: Supporting Irrigation Districts
Funded Fiscal Years: 2014
Keywords: nuisance aquatic plants, irrigation, water delivery systems, water quality

Research Question

Can we gain an understanding of canal characteristics and local environmental factors that promote or conversely discourage the growth of nuisance aquatic plants (NAPs) and apply this information to identify a comprehensive solution to controlling them.
Current mechanisms for dealing with NAPs are mechanical (i.e. physically removing plants from intake structures or burning them during the off-season) or chemical (i.e. treating with herbicides). The physical methods are often effective for only a short period of time and are used to keep chemical treatments to a minimum. However, many of the NAPs grow rapidly and cannot be maintained by physical removal alone. This requires that the combination of mechanical and chemical treatments must be used. The chemical methods, although effective, are becoming increasingly difficult to implement given the strict environmental regulation associated with the herbicides. In addition, occasional accidental releases have resulted in fish kills in downstream receiving waters.
Although not fully understood, local physical characteristics of canals and water quality seem to be a factor in whether or not NAPs will pose a problem within the system. By understanding the conditions that influence the growth of the plants more comprehensive solutions to the problem can be found, allowing irrigation districts and canal operators to manage NAPs without severe off-site and non-target impact or high labor and materials costs.

Need and Benefit

NAP issues are wide-spread and can be very costly to control. The western U.S. is predominantly arid and highly dependent on a network of reservoirs and delivery canals for agricultural water distribution. NAPs, such as filamentous algae and rooted aquatic macrophytes, are a growing problem in these canal systems. Flow through water delivery systems can be greatly reduced or completely obstructed by the growth of NAPs. In addition, NAPs can impair the performance of intake structures and pumps, or could otherwise cause serious damage to the system. Increased sedimentation rates in canals and drainage systems are also exacerbated due to the changes in design velocity effected by NAPs.
Canal operators and irrigation districts must hire physical labor to continuously remove the material from the systems and/or purchase and apply aquatic herbicides. It is also becoming increasingly time-consuming to obtain use permits for aquatic herbicides. Additionally, increased sedimentation directly results in increased general maintenance costs.
The primary goal of this scoping project is to assemble a team of resource specialists and managers who have practical experience with NAP issues and are representative of Reclamation's broad geographic extent to develop a systematic approach to studying the NAP issue. This effort will be formalized in a research proposal as a product of this project. The research proposal will be put forward for funding through upcoming Science and Technology Program cycles.
The goal of future research will be to identify conditions that influence the presence of NAPs and use that information to develop alternate control methods that are more cost-effective than the current control efforts. Costly control diverts funds and resources that could otherwise be applied to other critical maintenance and improvement projects. The future goals of this project would address this.

Contributing Partners


Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Nuisance Aquatic Plant Control in Water Delivery Systems (final, PDF, 476KB)
By Dale Lindeman
Report completed on November 24, 2014

Nuisance aquatic vegetation (NAP) in canals severely impacts water delivery systems and distribution of water for irrigation. Chemical treatments and mechanical removal to control NAP are costly and hard to implement. A team of resource specialists/managers worked to prepare a 3-year investigative study on conditions that influence the growth of NAP. Identification of these factors could lead in developing methods to control growth of NAP thereby reducing chemical/mechanical controls costs.
Keywords: nuisance aquatic vegetation, nap, chemical treatment, mechanical removal costs

This information was last updated on December 19, 2014
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