July 24, 2018

Dear West Richland Residents,

The City of West Richland is continuing to take action near the seven-acre wetland located between Keene Road and Willowbend Street commonly known as the Paul Keith Wetland Reserve to reduce the risk of West Nile virus to our residents. As part of that effort, the City of West Richland, Benton County Noxious Weed Control Board and Benton County Mosquito Control, in cooperation with the Benton County Clean Air Authority, Washington State Department of Ecology, Kennewick Irrigation District, and Benton County Conservation District are working to minimize noxious weed and mosquito development in the area.

Phragmites, or common reed, is a large perennial grass that has overwhelmed the area leaving no visible open water. This non-native noxious weed infestation is preventing the growth of native vegetation and making the wetland uninhabitable for fish and other wildlife.

The location has now become a public health concern. On June 26, 2018, Benton County Mosquito Control notified the City of West Richland of a West Nile virus positive mosquito sample collected near the Paul Keith Wetland Reserve. Mosquito Control continues to treat and monitor the site on a regular basis and to date has not detected another positive mosquito sample.

In order to prevent mosquitoes from emerging from the site in the future, the vegetation will need to be managed so that products used to kill mosquito larvae can reach the water. The wetland may also be stocked with Gambusia affinis, or mosquitofish, as a biological control agent.

Our research indicates the most effective phragmites control method is to spray the reeds with the herbicide Imazapyr. Simply removing the reeds is not an option because the seeds will disperse and the vegetation will return in the spring. Benton County Noxious Weed Control Board, under an inter-local agreement with the City, will be contracting with a helicopter pilot to complete the herbicide applications in early September 2018. When the conditions are favorable to minimize herbicide drift, the application will take place in the late morning (approx. 10:00 AM). It should take less than an hour to complete. Follow-up annual herbicide applications will need to take place to prevent the reeds from reestablishing.

We hope that you will support our efforts to address the noxious weed and mosquito issue at the Paul Keith Wetland Reserve to reduce the risk of West Nile virus for your family. For more information please contact any of the entity representatives listed below.


Roscoe Slade
Public Works Director


Angela Beehler
District Manager
Benton County Mosquito Control
(509) 967-2414

Roscoe Slade
Public Works Director
City of West Richland
(509) 967-5434

Vic Reeve
Weed Control Coordinator
Benton County Noxious Weed Control Board
(509) 943-6005