Senator Wyden held a congressional hearing in Washington on the water crisis last week.
Tribes decided earlier this month to exercise newly won water rights -- and that will mean less water for farmers.
Water agreements signed in 2010 between Pacificorp, state regulators, tribes and environmental groups still have to be approved by congress.
Senator Wyden says currently the Klamath Basin Restoration Agreement is too expensive.
"After considerable thought, I have concluded that the KBRA and essentially what has been agreed to at this point is simply unaffordable in the current feeral budget environment. My message on this point is working in good faith, there's got to be a way to accomplish the agreement's objectives with a lower price tag."
Wyden views the restoration agreement as a take off point for negotiations and not a done deal.