The Chattahoochee river runs from north Georgia southward to the states border with Florida despite being Over 400 miles long it is not a major artery for trade why is this the case

Even though the Chattahoochee River has the sufficient depth and width for part of its flow, namely from Columbus to its mouth at the sea, it is not used for trade because it simply not possible. The reason why it is not possible, is that there's a dam built on it, so it is not possible for any ships or boats to pass the dam and continue their sail up the river.