Any county, city, town, political subdivision, or other municipal or quasi municipal corporation authorized to issue revenue bonds may include in the amount of any such issue funds for the purpose of establishing, maintaining or increasing reserves to:
(1) Secure the payment of the principal of and interest on such revenue bonds; or
(2) Provide for replacements or renewals of or repairs or betterments to revenue producing facilities; or
(3) Provide for contingencies, including, but not limited to, loss of revenue caused by such contingencies.
The authority granted pursuant to this section is additional and supplemental to any existing authority to issue revenue bonds and nothing in this section shall prevent the issuance of such bonds pursuant to any other law: PROVIDED, That no such bond issue may include an amount in excess of fifteen percent thereof for the purpose of establishing, maintaining or increasing reserves as enumerated above.