I have had this book for a couple of years. Where the Great River Bends is a compilation of natural and historic essays on Wallula Gap.
I have the personal opinion that the Gap may be the most underappreciated landscape features in Washington State. This book of essays on the geology, plant communities, and history further enhanced my own appreciation of this remarkable landscape. Good geology including how the gap was initially cut, not by the Columbia River, but by the Clearwater River - currently a tributary of the Snake. The river in the gap is slackwater from McNary Dam downstream of the gap. The book does a great job of explaining the secondary consequences of the river no longer have the massive floods through the gap followed by much lower water - not just on the river but on the surrounding uplands. As windy as the area northeast of the gap is, the dust and blowing sand are much diminished from the old days. Pacific Northwest history passed through the gap from Lewis and Clark, Hudson Bay Company traders, naturalist David Douglas and explorer John Thompson. Today a great deal of commerce passes through the gap via barge and the railroads that line both sides of the gap. This is the route of the recently famous very heavy Powder River coal trains on the way to the coal port in British Columbia.
In a different era I ran and hiked the rim of the west side of the high cliffs above the Columbia River at this water gap accessing the area via back roads from Kennewick. It was one of the pleasures of living in Kennewick to have such a landscape nearby.