The governing body of any municipality bordering upon the Atlantic ocean may appropriate and pay out of its treasury into the treasury of the United States to and for the credit of the secretary of war to be used and expended by him or under his direction, for work or works to preserve the coast of such municipality against encroachment by the ocean which may cause or tend to cause injury and destruction of the inland waterways, navigable rivers and waterways, riparian lands, public roads and boulevards of the municipality, a sum equal in amount to any sum expended or about to be expended forthwith by or on behalf of the United States in the construction of any such protective work or works on the coast of such municipality, of which expenditure or purposed expenditure a notice signed by the secretary of war of the United States, addressed to the governor, shall be sufficient evidence and such notice shall be sufficient authority for the governing body, the finance or auditing committee and the collector or treasurer of the municipality to pay the same. Such money may be taken out of any unexpended balance or balances of any appropriations or any cash remaining on hand and not otherwise appropriated, and if such balances and cash be insufficient for the purpose, so much of such sum as may be necessary may be included in the next annual assessment and raised by the regular tax levy of the municipality. Not more than one such auxiliary appropriation, which in no case under this section shall exceed fifteen thousand dollars, shall be made by any municipality hereunder. Such appropriation shall be paid into the treasury of the United States, as hereinbefore provided, only in conjunction with a like equal payment from the county in which the municipality is located.