OTREC-RR-11-17River freight plays a vital role in the Lower Columbia River economy. The link to land transport can be disrupted if channel depths are shallower than expected. 70% of cargo is carried by vessels with a draft close to low water channel depth. A large vessel may have as little as 0. 6 m clearance at low tide. River changes exacerbate the situation low water levels have decreased 0. 3 1. 2 m since 1940. An ongoing 0. 9 m channel deepening will cost