Colo. Rev. Stat. § 37-44-140
For the purpose of defraying the expenses of the organization of the district, and the repair, operation, management, and improvement of all reservoirs, inlet works, outlet works, drainage works, canals, and works for the protection of life and property from floods, washing, and inundation, including salaries of officers and employees, the board may provide, in whole or in part, for the payment of such expenditures by levy of assessments therefor as provided in section 37-44-119, if the money raised by the sale of bonds issued is insufficient. In case bonds are unavailable for the completion of the plans of works adopted, the board of directors may provide for the completion of said plans by levy of an assessment therefor in the same manner in which levy of assessments is made for other purposes.
C.R.S. § 37-44-140