In a recent magazine "The Atlantic" author Mark Byrnes wrote about the city of Baltimore's' method for cleaning up the tributaries that empty into it's harbor. They have created a solar powered water wheel that picks up debris and is able to collect the material for proper disposal rather than in the bottom of the harbor.
Read the full article through the following link.

Alex Pearl
http://www.citylab.com/design/2014/05/a-giant-wheel-is-cleaning-up-baltimores-garbage-filled-harbor/371293/