A04_SOW_Herbicide_Spraying.pdf

Statement of Work

Imperial National Wildlife Refuge (INWR)

Tamarisk Control Project – Herbicide Spraying & Cut-Stump Treatments

Yuma County, Arizona October–December 2025

BACKGROUND

This Statement of Work outlines the implementation of invasive species control treatments on lands within Imperial National Wildlife Refuge (INWR) burned in the Refuge Fire on May 25, 2024. The fire affected 1,041 acres, including critical riparian and desert thornscrub habitat. The burned area contains high densities of tamarisk (Tamarix spp.), an aggressive non-native species that resprouts prolifically after fire and threatens native habitat recovery and long-term ecological resilience. As part of the Refuge Fire

Burned Area Rehabilitation (BAR) Plan, INWR has prioritized cut-stump and low-volume basal bark herbicide treatment of tamarisk across select high-priority restoration units. These treatments will help reduce competition with native plantings (e.g., cottonwood, willow, mesquite) and are essential to maintaining habitat suitability for Southwestern Willow Flycatcher, Yuma Ridgway’s Rail, and other sensitive species.

DESCRIPTION OF PROJECT NEEDS

Imperial NWR seeks a qualified contractor to perform targeted tamarisk control treatments on up to 100 acres of previously burned and now regrowing vegetation. Treatment units are located within designated restoration areas where BAR revegetation work is ongoing. The primary objective is to prevent tamarisk re-establishment through cut-stump herbicide application and basal bark spraying of tamarisk resprouts.

These treatments are crucial to the success of BAR habitat rehabilitation and will be used in conjunction with other mechanical and restoration activities over a multi-year period.

PLACE OF PERFORMANCE

All work will take place on U.S. Fish and Wildlife Service-managed lands within Imperial National

Wildlife Refuge, specifically within the Refuge Fire perimeter. Restoration units will be identified on maps provided at the pre-project kickoff meeting and are accessible via refuge roads and boat-access routes along the Colorado River.

SCOPE OF WORK

The contractor shall provide all personnel, equipment, supplies, facilities, transportation, tools, materials, supervision, and other items and non-personal services necessary to perform herbicide control of salt cedar resprouts, on Imperial National Wildlife Refuge. The required herbicide will be provided by the

USFWS for use on this project. The contractor shall perform to the standards in this contract and will have on the ground guidance project and planning guidance directed by refuge staff.

Objectives:

• Provide supervision and oversight of personnel while cut stump spraying a total of up to 100 acres of salt cedar resprouts that range from 6” to 4’ tall. Work areas will be mapped via an Avenza map and will be provided upon selection at the kick-off meeting.

• Conduct tasks such as mixing and spraying while following all pertinent protocols and applicable laws.

• Maintain proper safety and efficiency measures as directed by refuge personnel and crew leader.

• Provide GPS coordinates of all areas sprayed and documentation on herbicide and methods used in each area.

PERIOD OF PERFORMANCE

Start Date: October 1, 2025

End Date: January 1, 2026

HOURS OF OPERATION

The Contractor is responsible for conducting business, between the hours of sunrise to sunset Sunday through Saturday except Federal holidays at the contractor’s option. The contractor must, at all times, maintain an adequate workforce for the uninterrupted performance of all tasks defined within this contract when the government facility is not closed. When hiring personnel, the contractor shall keep in mind that the stability and continuity of the workforce are essential. The facility is closed on recognized Federal holidays. The contractor is not required to perform work on these holidays:

New Year’s Day, January 1st or the Friday preceding or Monday following

Martin Luther King’s Birthday, 3rd Monday in January

President’s Day, 3rd Monday in February

Memorial Day, Last Monday in May

Juneteenth, June 19th or the Friday preceding or Monday following

Independence Day, July 4th or the Friday preceding or Monday following

Labor Day, 1st Monday in September

Columbus Day, 2nd Monday in October

Veteran’s Day, November 11th or the Friday preceding or Monday following

Thanksgiving Day, 4th Thursday in November

Christmas Day, December 25th or the Friday preceding or Monday following

HERBICIDE & APPLICATION NOTES

• Basal bark treatment: Apply 20% triclopyr ester (Garlon 4 Ultra or equivalent) in a vegetable oil-based carrier to tamarisk resprouts 3–6 feet tall, treating the lower 12–18 inches of the stem.

• Cut-stump treatment: Immediately apply 10% imazapyr (Habitat or equivalent) with nonionic surfactant (0.25% v/v) to freshly cut tamarisk stumps.

• Spraying should cease when daily high temperatures exceed 85°F to avoid volatilization.

• Application should be by handheld or backpack sprayer only—no aerial or high-volume equipment will be used.

• All applications must follow DOI and FWS herbicide use policy, and any required

Pesticide Use Proposal (PUP) approvals.

CONTRACTING OFFICER’S REPRESENTATIVE (COR)

Benjamin Stewart

Assistant Fire Management Officer

Imperial National Wildlife Refuge

Phone: 928-920-1302

Email: benjamin_stewart@fws.gov

OR

Chayne Best

Prescribed Fire Tech

Imperial National Wildlife Refuge

Phone: 928-210-8189

Email: chayne_best@fws.gov

SPECIFIC TASKS

The contractor shall remain in close contact with the FWS COR and Staff. Contactor is responsible to ensure all pertinent information is clearly understood. Contractor will relay all the job task information the workforce prior to the first day of planting. Follow all protocol for the spraying process as described by refuge staff. Meet daily with Refuge Staff to discuss the progress and plans for the following day.

Assist in changes and modification to the plan and workday as needed. Perform all the objectives as listed in “Scope of Work”. Adhere to the daily schedule. Follow all National Wildlife Rules and Regulations, including fire safety while on site.

mailto:benjamin_stewart@fws.gov mailto:chayne_best@fws.gov