The county is authorized and empowered to enter into agreements with the appropriate federal agency for the use of federal funds to construct, improve or maintain roads, other than state highways, within or partly within national forests or BLM properties; provided, that the share of the county in the cost of such cooperative road project shall be paid from county road funds; provided further, that donations may be accepted in lieu of appropriations from county road funds. (1988 Code § 9.04.020)