Cheaper capital cost – Nature has already done the initial engineering work for the transportation infrastructure, the cost of developing an inland waterway is 5-10% of the cost developing an equivalent railway or a four-lane expressway.[citation needed] This varies a lot, depending on whether the waterway is naturally navigable, whether only ports are needed, or whether a canal and locks are needed. Cheaper maintenance cost – The maintenance cost of an inland waterway is only 20% of the maintenance cost of an equivalent roadway. The main expenses associated with waterway maintenance include dredging and invasive species control.[citation needed] Greater fuel efficiency (low cost of transportation) for large freight – It is estimated that 1 liter of fuel can move 105 ton-km by inland water transport.