A district may, but shall not be required to, contract with the United States, the State, or any agency or political subdivision thereof, or any person, for the construction, operation or maintenance of works, facilities or operations within or without the district boundaries which the board deems necessary to protect the land in, and property of, the district, from damage by flood or overflow, and may contribute to the cost or expense thereof out of its general fund or any special fund provided therefor.