What is the strange-looking orange machine I saw on the Sudbury River?

This is an aquatic weed harvester owned by the Great Meadows

National Wildlife Refuge used to help combat invasive aquatic plants on the Sudbury River. The harvester has also been generously loaned to neighboring towns such as Sudbury. Information on other usage in Sudbury as well as considerable information on invasive aquatic plants can be found on the Hop Brook Protection Association site at:

http://www.hopbrook.org/id19.htm

The State of Massachusetts recognizes invasives as a widespread problem with more information at:

http://www.mass.gov/dcr/waterSupply/lakepond/invasive_1.htm

The USDA also provides a reference site:

http://www.invasivespeciesinfo.gov/aquatics/main.shtml

Many communities across the country are having to come up with ways to approach this problem and learn from each other. The Water Chestnut is among the most notorious problems in the northeast. The Management Plan for Chesapeake Bay in Maryland is an excellent point of reference and history:

http://www.anstaskforce.gov/Species%20plans/Water%20Chestnut%20Mgt%20Plan.pdf