The authorities of any municipality in which there is situated and located, in whole or in part, a port of entry through which commodities are imported and exported to foreign nations, which maintains a channel and/or harbor to a depth of not less than twenty feet, are hereby given the authority to engage in, through the agency hereinafter provided and designated and such other agencies as hereinafter may be provided by law, work of internal improvement, or promoting, developing, constructing, maintaining, and operating harbors or seaports within the state and its jurisdiction, acting through the commission hereinafter provided for, shall have the power to acquire, purchase, install, lease, construct, own, hold, maintain, equip, use, control and operate at seaports, wharves, piers, docks, quays, grain elevators, cotton compresses, warehouses and other water and rail terminals and other structures, and facilities needful for the convenient use of the same in the aid of commerce including the dredging of approaches thereto, provided that such work on improvements and facilities shall always be and remain under the management and control of said municipality through the governing agency hereinafter provided and designated, or other such governing agency or agencies as hereinafter may be provided by law. The entire cost of the said municipality of engaging in such work or development shall not exceed the sum of one million dollars ($1,000,000.00).