C.R.S. § 32-11.5-601

(1) The territorial limits of the watershed management area may be enlarged by the annexation of additional real property thereto: (a) By petition and consent of the fee owner pursuant to sections 32-11.5-602 and 32-11.5-606 ; (b) By petition of the eligible electors pursuant to sections 32-11.5-603 , 32-11.5-604 , and 32-11.5-606 ; (c) By action initiated by the district pursuant to sections 32-11.5-605 and 32-11.5-606 with the consent of the governing body of each county or municipality that includes any of the real property to be annexed; or (d) By petition by the governing body of each county or municipality that includes any of the real property to be annexed.