Why were the distributary channels in the Yukon River delta difficult for riverboats to use?

The distributary channels in the Yukon River delta were difficult for riverboats to navigate primarily because many of them were too shallow. The delta region itself is characterized as being swampy and covered with lakes, which creates a complex and challenging environment for water transport. While most of these channels lacked sufficient depth for navigation, the northeastern channel, known as Apoon Pass, was historically utilized by riverboats to access the river.1