Newman Lake shore to close next week for herbicide treatment

Spokane County is asking boaters and swimmers to stay out of Newman Lake next week as the lake is treated with herbicides to control invasive aquatic weeds.

About 60 of the 1,200 acres of Newman Lake, which is 20-miles northeast of Spokane and two miles west of the Idaho border, will be treated with a herbicide to kill weeds on Wednesday. Swimmers should stay out of the water for at least 48 hours after the treatment.

Martha Lou Wheatley-Billeter, Spokane County Public Works information and outreach manager, said the chemicals irritatie the skin and eyes, and if ingested, cause vomiting, stomach cramps and diarrhea.

Wheatley-Billeter said boating is also discouraged during the treatment because it could stir up the water and dissipate the chemicals, making the annual treatment far less effective.

Aquatic Weed Solutions, the company the Newman Lake Flood Control Zone District hired to treat the lake, will use 2-4-D Amine, which is dichlorophenoxyacetic acid and dimethylamine salt. The treatment will kill Eurasian Milfoil , an invasive plant categorized as a noxious weed by the state’s Noxious Weed Control Board. It is an ornamental plant that escaped cultivation and can form dense mats and degrade water quality.

In addition to swimming and boating being discouraged, the Washington Department of Fish and Wildlife public access area on the east side of the lake will be closed Wednesday and Thursday. The gates to that area will be re-opened Friday.

Those who use Newman Lake water for irrigation and household use should wait until seven days after the June 24 treatment to use the water again. Mailed notices have been sent out to shoreline residents.