The city shall have the right to lease the area so created between the said shore lines and the wharf lines so established or any part, parts or parcels thereof during times when the use thereof is not required by the city, for periods not exceeding thirty years, to private individuals or concerns for wharf, warehouse or manufacturing purposes at such annual rate or rental per lineal foot of frontage on the canal or waterway as it may deem reasonable.

The rates of wharfage, and other charges to the public which any lessee may impose shall be reasonable; and the city council or commission may regulate such rates. The lease so granted by the city shall never be transferred or assigned without the consent of the city council or commission having been first obtained.

A city shall never lease to any individual or concern more than four hundred lineal feet of frontage of the area lying between the shore lines and the dock lines and no individual or concern shall ever hold or occupy by lease, sublease or otherwise more than the said four hundred lineal feet of frontage of such area: PROVIDED, That any individual or concern may acquire by lease or sublease whatever additional number of lineal feet of frontage of such area may in the judgment of the city council or commission be necessary for the use of such individual or concern, upon petition therefor to the city council or commission signed by not less than five hundred resident freeholders of the city.