Okla. Stat. tit. 11, § 11-36-111: Change of grade - Compensation to abutting owners

No change of any grade previously established by a municipality

shall be made without making due compensation to the owners of

abutting property for any damage thereby caused to permanent

improvements erected on the abutting property with reference to the

grade previously established. However, the failure to make such

compensation shall not invalidate any assessments on the property

chargeable with costs of a grade change as provided by law on street

improvements.