(a) The Regional Administrator may provide up to 95 percent of the approved work plan costs for Tribes or Intertribal Consortia establishing a section 106 program. Work plan costs include costs of planning, developing, establishing, improving or maintaining a water pollution control program.

(b) The Regional Administrator may increase the maximum federal share if the Tribe or Intertribal Consortium can demonstrate in writing to the satisfaction of the Regional Administrator that fiscal circumstances within the Tribe or within each Tribe that is a member of an Intertribal Consortium are constrained to such an extent that fulfilling the match requirement would impose undue hardship.