A deadline has been set for water adjudication to be completed by June 30, though Klamath County’s local watermaster said it should be finished in advance of the next irrigation season.

Adjudication, which has been ongoing since 1975, will tell water users in the Klamath Basin whose water rights are senior and whose are junior, based on the priority date of their claims. This means a junior water user could have irrigation supply shut off if someone with a senior water right makes a claim to that water.

Scott White, Oregon Water Resource Department’s district 17 watermaster, will deal with such water shutoffs, but he isn’t in charge of turning anyone’s water on.

For example, if a farmer uses water from the Williamson River, and the river’s flows fall below a certain level guaranteed by someone else’s claim, the watermaster could double-check the flows and shut off that farmer.

Bud Ullman, water lawyer for the Klamath Tribes, said the Klamath Tribes’ water rights are considered to be time immemorial, so they will be adjudicated as the most senior rights. Other early water claims were informally written down on fence posts, he said. Claims completed after 1909, when Oregon’s Water Code went into effect, were filed in Salem with amounts of water and priority dates.

Types of claims to be adjudicated include in-stream, irrigation, storage, wetland, and lake levels.

The majority of tribal claims are in-stream, meaning that designated water will stay in the streams, rivers and Upper Klamath Lake. This water supports hunting, fishing, trapping and gathering.

In addition, Ullman said there are 30 irrigational claims from tribal allottees, who received land with the termination of the Klamath Reservation in 1954. These claims extend back to the creation of reservation lands in 1864.

“Adjudication is quite likely to have a significant impact,” Ullman said.

Adjudicated claims indicate priority date, source of water, place of use, season of use and flow/rate of water.

“One of my biggest fears,” White added, “is people won’t be aware of what’s coming.”