Part of the dam has stopped debris from flowing on. Mixed in with all the branches and wood was a lot of plastic. How much plastic can you find in this picture?
It looks like dams stop quite a bit of plastic from making it all the way to the ocean, but they don't catch everything, especially if the water gets high enough. There are different types of dams, some that allow water to pass, and some that don't. Many dams are built with a spillway. A spillway is a section of a dam designed to pass water from the upstream side of a dam to the downstream side.
The day before Hurricane Irene hit New England a couple years ago I went to the Holyoke Dam which is further down the Connecticut River. The Holyoke Dam has been providing power to the Paper City since 1870, when it was rebuilt. It is an hidro-electric dam with several channels, overflows and waste-weirs. (www.holyokemass.com)
Twelve channels divert water to power the hydro-electric turbine. The dam is designed to allow a steady flow independent of the water level. If it gets high enough, the water flows right over the waste-weir dam.
During Irene, whole houses were floating down the Connecticut. I was able to get some shots the day after. I went to Springfield and Bellows Falls. I saw a porch, a couple gas tanks, lots of various plastic bottles and containers, several basket balls, and a lot of lumber. The person next to me said they saw a fiberglass bathtub going down the river just before I showed up.
A lot of debri went out to sea from Irene, But it isn't just after a big hurricane that you see plastic flowing down the river. Last fall we were exploring places to go kayaking, and we found a current along the Connecticut that had collected several items of plastic trash.
There is something about rivers. People have been living near rivers since civilization began. Before the Industrial Revolution, it was one of the main sources of transportation, one of the main sources of power. Rivers provided drinking water, and connected communities. You can still travel from town to town, by river. Many cities are built on the shores of rivers. Waste made by man has flown out to sea for centuries. But until the invention of plastics most waste would biodegrade. Now the waste that flows down the river will outlive us five times. The next time you are out enjoying the nice weather this spring, please take the time to pick up three plastic items you see littering the streets. Most likely there is a river or steam near by that leads to the sea.
