My trip down the most endangered river in America

After three weeks and about 400 miles, I finished my kayaking (and walking) journey down the "most endangered" river in America: California's San Joaquin. This page collects the tweets from my adventure. The journey started way up in the Sierra Nevada Mountains and ended beneath the Golden Gate Bridge in San Francisco on July 4. On that trip, I saw a wedding and a baptism on the river; met farm workers who are unemployed because the river doesn't carry enough water for everyone; witnessed the moment the river dries up and becomes nothing but sand; and met readers who have seen my posts about all these things and decided to join me on the path. The San Joaquin provides water to California's Central Valley, which grows 40% of the fruits and vegetables produced in the US. It's a forgotten but important part of the state -- and a forgotten but enormously important river. That's why I spent so much time with the river, trying to draw attention to the water crisis in the "other California." Look for more soon, and check out other stories in the Change the List series at CNN.com/Change. -- John