Colo. Rev. Stat. § 32-14-118
The payment of special obligation bonds may be secured by the specific pledge of sales tax revenues of the district, operating revenues of the district, or moneys or assets of the district held in escrow as the board, in its discretion, may determine. Operating revenues, sales tax revenues, or moneys or assets held in escrow pledged for the payment of any special obligation bonds, as received by the district, shall immediately be subject to the lien of such pledge, without any physical delivery thereof, any filing, or further act, and the lien of such pledge and the obligation to perform the contractual provisions made in the authorizing resolution or other instrument relating thereto shall have priority over all other obligations and liabilities of the district, except as may be otherwise provided in this article or in such resolution or instrument, and subject to any prior pledges and liens previously created. The lien of such pledge shall be valid and binding as against all persons having claims of any kind in tort, contract, or otherwise against the district, regardless of whether such persons have notice thereof.
C.R.S. § 32-14-118