Udic moisture regime in an arid climate?

I am currently working in Central Oregon (east of the Cascades) where upland soils are generally xeric. However, I work strictly
on riparian soils. There are several situations where I have a hard time calling soils that are not aquic, xeric. These include
oxyquic soils and soils that just dont dry out but are also not reduced.
Has anyone else run into this situation and would it be valid to classify soils udic when the climate is pretty arid?
Thanks for any comments.
Eric Nicita