"Civilization haunts the waterways". Alfred North Whitehead
This is an interesting project, "RiverCube Project" (2003/2004). Not sure if it's still going on - the website could use some updating and or end dating. Naturally - it peaked my interest as I collect beach trash for my art making and this project collects trash from river ways for gallery art works and educational community projects.
(FYI- I came across it at http://ecosalon.com/20_unforgettable_works_of_environmental_art/ - also worth a look.)
"RiverCubes are catalysts. They do whatever it is they do: surprise, confuse, delight, amuse, offend… They are an intervention into the ‘business as usual’ of waste. They intend to provoke thought and incite action. Foot soldiers in a public education campaign, RiverCubes are slices of time, breadcrumbs along a trail of urban watershed signatures. RiverCubes have work to do - and do their work best by being displayed in proximity to their collection sites."
"RiverCubes Projects engage community groups in volunteer work that yields a first hand acquaintance with issues of water quality, solid waste management, and urban human ecology - vital to the health and welfare of biotic communities on which we depend and of which we are a part." visit: http://www.rivercubes.net/.