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Notice Of Intent To Spray - Stormwater Utility Infrastructure

Government and Politics

July 30, 2022

From: City of Davis

Notice: Spray notification to apply Capstone and Telar inside security fenced areas (not accessible by the public) including driveways, fence lines and infrastructure. This allows the City to maintain clear and safe areas around pumps and control systems that require a clear and debris free zone. These weeds pose a critical infrastructure risk to the pump stations because vegetation will root on edges and in cracks, and eventually undermine the integrity of the facility. PWUO staff also need to be able to safely access stations throughout the year to perform maintenance and react to changing conditions during the rainy season. Spraying will take place as conditions permit during operational hours August 1 - August 4, 2022.

Locations to spray:

- Storm Drainage Station #1 on W Covell Blvd.
- Storm Drainage Station #2 on F St.
- Storm Drainage Station #3 on H St.
- Storm Drainage Station #4 on 2nd St.
- Storm Drainage Station #5 South of I-80 at Causeway
- Storm Drainage Station #6 on Richards Blvd.
- Storm Drainage Station #7 on Road 99 D
- Storm Drainage Station #8 on Shasta Dr.
- Storm Drainage Station #9 on Cannery Loop

Pesticide: Capstone (Triclopyr Triethylamine Salt, Aminopyralid Triisopropanolamine Salt), Telar (Chlorsulfuron2-Chloro-N-[(4-methoxy-6-methyl1,3,5-triazin-2-yl)aminocarbonyl]),

Target Pests: Pepperweed, short-pod mustard, yellow star thistle, Mare’s Tail, Russian thistle, Stinkwort, Prickly Lettuce, fluvellein, other broad-leaf annual weeds.

Methods Used and Strategies to Prevent Future Use: Pepperweed is of particular concern because there is no reliable way to control it without herbicide. Mechanical cultivation or hand hoeing are not options because the plant can reproduce from vegetative material and these methods will actually increase the infestation. The plant can cause damage to stations and well sites because it’s large, tuberous roots can undermine pipes, foundations and other facilities. Other weeds, including yellow star thistle, provide significant fuel for fire, burning hotter than grasses due to a high oil content. There is no reliable way to kill these weeds using non-chemical methods at the scale they exist on the sites.

This is part of the overall integrated pest management of the site. This well-timed application will decrease pesticide usage over time by preventing seed-set in the annual weeds and killing reproductive material in perennial plants. This will result in smaller infestations over time, allowing mechanical techniques to be more effective. However, the need for access to secure public safety may affect this trend, depending on conditions such as rainfall amounts, timing and ground temperature. Stormwater crews use the following cultural practices to prevent the need for chemical herbicide use:

- Spray timing is critical to effective control and reduced use over time. The proposed timing of the spray is before annual grass seeds set, preventing another generation of weed growth.   
- Stations with asphalt surfaces will be crack-sealed this summer to prevent future infestations in those areas.
- Double-check surrounding areas during dry months to make sure no irrigation over-spray is affecting conditions.
- Keep sites and stations maintained to prevent flooding of access areas and deposition of weed seeds.
- Practice responsible vehicle access during wet months to prevent road damage and the need for repair work that is a vector for invasive species.
- Clean and maintain all equipment before and after use to prevent the transfer of seeds and plant materials between sites and/or into sensitive areas.   
- Continue to promote the use of tree canopy to shade conveyance channels and prevent weed growth that blocks flow.     

The areas will be posted with the intent to spray, and after application, as required in the city's Integrated Pest Management (IPM) Program Policies and Procedures.

More information on the IPM Program, including the current Policies and Procedures guidance, can be found on the city's webpage: Integrated Pest Management