When the wharf or chute is completed and the tolls or wharfage fixed, the owner is entitled to a license to take tolls for the term of one year. The license shall be issued by the county auditor on the payment of such license tax as the board may fix, which tax, except for the first year, shall not be more than ten per cent of the gross receipts for tolls or wharfage for the previous year. The fee shall be paid to the county treasury for general road purposes.