I mean, the problem is that paper or reusable bags aren't any better for the environment than the plastic bags.
Whether or not your reusable bag is better depends upon the material the recycled bag is made from. The amount of energy consumed during bags' life cycles vary hugely depending on what exactly the bag is made from. So, unless every single person starts using organic cotton reusable bags instead of the plastic bags from the grocery store, we're accomplishing nothing except making it incredibly inconvenient for DC residents to grocery shop.
The difference in the bags is almost entirely in how we perceive them. Now, reusable bags are more like a fashion statement instead of actually doing any better for the environment. Besides, there were plenty of people like me who took plastic bags and then reused them until they fell apart (I still do with the ones I have left)
And if we're after cleaning up the river, charging $0.05 per bag seems like the worst way to accomplish that ever. Maybe we should focus on littering or, I don't know, people who dump waste into the water?