Water Quality

At Selah-Moxee Irrigation District we pledge to provide clean reliable irrigation water to our customers in a professional and efficient manner, while maintaining and improving District operations, facilities, and water rights in order to meet the needs of our customers while earning trust and respect of those we work with daily.

In order for the District to meet its’ mission to provide “clean reliable irrigation water” the canals and ditches must be treated with aquatic herbicides to prevent the growth of vegetation within the canal system. If the canal vegetation is left unchecked, it would lead to reduced water deliveries, reduced canal capacity, increased canal seepage, and even canal failure. The use of aquatic herbicides is an important tool to ensure that the canal system continues to operate efficiently by providing water that meets the needs of our customers.

Therefore, the Selah-Moxee Irrigation District has developed a canal aquatic treatment program through the District’s NPDES Permit WAG 991016A to control canal vegetation through the use of products like Cascade/Teton (Endothall), Nautique, Copper Sulfate, as well as others. (See Public Notice below).

In addition to our vegetation management program, the District does conduct Global Gap water quality testing for our growers who are reliant upon this information. Global Gap testing is conducted once a month beginning in May and ending in October. Links to the results will be posted here when they become available.

Selah-Moxee Irrigation District will be conducting our aquatic weed treatment program as follows in the chart below.

However, these dates may be subject to change depending on conditions. If you do not wish to use treated water for any reason, you are advised to discontinue using the irrigation water, beginning on the day of treatment and for at least two days thereafter.

Treatments made with copper are labeled as being toxic to fish.  If you use your irrigation water for fish rearing, you are advised to discontinue using the irrigation water, beginning on the day of treatment and for at least two days thereafter.

The Selah-Moxee Irrigation District will be applying aquatic weed herbicides to its irrigation canals in accordance with Washington State Department of Ecology pesticide laws.

The purpose of the herbicide application is to control aquatic weeds within the irrigation delivery system.

Treatments will be made to the majority of irrigation canals within the boundaries of the Selah-Moxee Irrigation District located within Yakima County, Washington.

The herbicides to be used will be Copper Sulfate, Nautique, and Endothall (Cascade/Teton).

Herbicide applications are generally made every two weeks typically starting around April 10 and ending in October as needed depending on weather and canal conditions. The treatment site will be at the Pomona Head-Works along with various sites throughout the district. Sites with public access will be posted with the name and telephone number of the Selah-Moxee Irrigation District.

Waters within the Selah-Moxee Irrigation District are intended for agricultural purposes only and are not to be used for human consumption. Avoid human contact. Canals within the Selah-Moxee Irrigation District can be dangerous and are not intended for public use and are restricted to district personnel only. District facilities are located on private property and are not to be trespassed.

Herbicide applications will be performed under the direction of licensed District personnel.

Selah-Moxee Irrigation District
113 East Moxee Avenue
Moxee WA 98936
(509) 469-0449
Washington Department of Ecology, Central Office (509) 575-2800
Nathan Draper, District Manager