Oregon Constitution Art. IX § 1c

The Legislative Assembly may provide that the ad valorem taxes levied by any taxing unit, in which is located all or part of an area included in a redevelopment or urban renewal project, may be divided so that the taxes levied against any increase in the assessed value, as defined by law, of property in such area obtaining after the effective date of the ordinance or resolution approving the redevelopment or urban renewal plan for such area, shall be used to pay any indebtedness incurred for the redevelopment or urban renewal project. The legislature may enact such laws as may be necessary to carry out the purposes of this section.