Each county of the state through which runs any river, stream or arroyo subject to flood conditions destructive to property or dangerous to human life shall be by the board of county commissioners, within thirty days after the passage and approval of this act N.M. Stat. Ann. § 4-50-10 to 4-50-17, divided into emergency flood districts, and said board shall set out the limits and boundaries of each said district, and cause the same to be properly numbered so that the same may be known and identified.