N.M. Stat. § 4-50-2
A board of county commissioners, upon certification of the need and estimated cost by the county flood commissioner, may contract to borrow funds through state or federal agencies or through the New Mexico finance authority for flood control purposes and may levy an annual tax at a rate not to exceed one dollar fifty cents ($1.50), or any lower maximum amount required by operation of the rate limitation provisions of Section 7-37-7.1 NMSA 1978 upon a tax imposed under this section, on each one thousand dollars ($1,000) of net taxable value, as that term is defined in the Property Tax Code [Chapter 7, Articles 35 to 38 NMSA 1978], of all the taxable property located within five miles of both sides of any river or stream which contributes to or is subject to flood conditions destructive to property or dangerous to human life. Such taxes shall be levied and collected for the purpose of creating a fund which shall be used to construct and maintain dikes, dams, embankments, ditches or such other structures or excavations necessary to prevent flood waters from damaging property or human life within such counties or to repay, according to their terms, any state or federal loans obtained for flood control purposes. Such tax shall be assessed, levied and collected as other taxes are collected and when so collected shall be known as the "county flood fund", and such fund shall be maintained in such a manner as to keep separate records of all flood control taxes collected from each stream or river drainage area. The taxes collected shall only be used and disbursed for flood control projects in the drainage area for which they were assessed in accordance with the provisions of Sections 4-50-1 through 4-50-9 NMSA 1978 and shall not be transferred to any other fund or purpose.
NMS § 4-50-2