Lower Charles River Flood Plain and Alluvial Soils

With this update, I will examine the lower Charles River Watershed. I briefly touched on the upper and lower Charles River Watersheds in a previous post. The division between upper and lower is drawn at the Watertown dam. Below is a map by the EPA showing the division and boundaries.

Image Source: EPA

The lower Charles River Watershed is dominated by development and heavy human use as the potion of the watershed that contains parts of Boston proper. As you can see, almost the vast majority of the lower basin is actively used by people for residential, commercial, transportation, or recreational uses. There are small patches of marshes, reservoirs, smaller streams, and the river itself but the land is largely developed and impermeable.

Image Source: Image Source: Zarriello, P. J., & Barlow, L. K., 2002

The streams, river, and runoff do deposit sediment for the soil in the lower watershed, but much of the area especially towards the city is artificial fill and urban land (Weiskel, P. et al 2005). The artificial shaping of the land near the city is a longstanding tradition and began in the 1600s when the first European settlers began expanding the city by leveling some of it's famous hills to fill in the land between what was a peninsula and the mainland (Mitchell, J. H. 2008).

Image Source: Zarriello, P. J., & Barlow, L. K., 2002

Below, you can see a map of what the shoreline would look like before the deliberate filling of the bay. Many of the places I visit everyday would simply be water or marsh.

Image Source: Weiskel, P. et al 2005

It is hard to imagine these areas without human development, and like it or not the land has been changed. To improve how this land is used, the work I described in my Special Threats post around preventing Combined Sewage Overflows and strengthening both the infrastructure and preparation for flooding remains a priority. 

Mitchell, J. H. (2008). Paradise of All These Parts: A Natural History of Boston (1st ed.). Beacon Press. Weiskel, P. K., Barlow, L. K., & Smieszek, T. W. (2005). Water resources and the urban environment, lower Charles River Watershed, Massachusetts, 1630-2005. U.S. Department of the Interior, U.S. Geological Survey. Zarriello, P. J., & Barlow, L. K. (2002). Measured and simulated runoff to the lower Charles River, Massachusetts, October 1999-September 2000. U.S. Dept. of the Interior, U.S. Geological Survey.