Natural Processes in the Back Bay
Introduction
Nature can be a major force to be reckoned with in a city. Hurricanes rage, floods devastate, and droughts can bring a city to its knees. But if the city is built with nature as its ally instead of its enemy, the same forces of nature can help mold and shape it into a more beautiful and livable habit for all. This site in Boston’s Back Bay Fens is a good case in point. In a mere five blocks of city there are examples of urban planning that brings together natural and manmade features in harmony, and there are examples of terrible blunders in planning. The area itself would not even exist were it not for the ingenuity and forward thinking of its original planners. Although the Back Bay Fens is an area of Boston that is almost completely man-made, it is, was, and will be shaped by natural forces.
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Earth
Looking at the Back Bay in an old atlas, one finds a common theme of nature in the area; water, and lots of it. Because the whole Back Bay was underwater originally, the area provides an interesting chance to analyze not only natural processes, but natural processes that were directly and substantially shaped by human hands. There was no earth in the Back Bay until the mid 1800’s. The one exception though, is this particular site. It stands out as one of the more interesting sites in the area because within its relatively small radius, it contains not just filled land, but natural earth as well. Looking to the map at left, one can see that real land comprises the south-eastern quarter of the site. This allows an intriguing look at how nature has shaped these two very different land masses over the years.
The first difficulty in comparing the filled land to the land from the original peninsula is finding the dividing line between the two. Even though it would be fairly simple to overlay a current map with an old atlas of the area, it would not quite provide precise enough information to determine the differences in land. An error of a sixteenth of an inch probably meant very little to an eighteenth-century cartographer drawing a piece of shoreline, but that error carried over onto today’s maps means a whole city block, give or take. So, in determining the differences between the types of land, it was best to compare to opposite corners of the site, thus ensuring that they were composed of the two types of earth. After a bit of thought, and a lot of walking back and forth across the site, the signs can easily be found.
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In observing the two known areas, both look very similar when looking from the street. Looking up and down Massachusetts Avenue on the east side of the site reveals nothing other than a slight sloping of the street toward the river. Where the differences can be seen is in the back alleys behind the buildings. On the south-eastern end of the site, the alleys have a good deal of angle to them, whereas the alleys of the north-west corner are all fairly level. The reason for this is that when constructing buildings on the original land, great care was taken in leveling the streets and the land beneath the buildings, but the alleys were not as important and kept their natural contours. The filled land though, was all leveled as it was built, so it is more uniform.
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Another difference is the characteristic settling of filled land. No matter how hard the engineers of the 1800’s tried to pack the land fill in tightly, there was no way they could match the gradual land forming processes of Mother Nature. Many brick areas of the filled portions show signs of sinking in below the level of the concrete with which they were originally laid flush. A good example of this is seen on the side of the Charlesgate condominiums. The bricks in this area show it more drastically than many others because of the storm drainage system right next to it on the side of the building. The added moisture from the rain-gutter water flowing under it helps the ground to settle and progressively lower the level of the bricks. Another factor in this is that these bricks were placed directly on top of the dirt underneath and had no mortar or sand placed between them. If the builders had considered the combination of the ground and the added water running under it, they could have laid down concrete beneath the bricks. Another idea would be to place a layer of gravel in that would not settle when extra water flow occurred.
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A more severe shifting of the ground occurs on the site where many underground utilities converge. The swelling and shrinking of all of these pipes and the subsequent temperature changes of the ground around them causes the road to shift and crack. The ground where the pipes are does not move in the same way that the surrounding ground does.
These differences in the land beneath the buildings helped shape the development of this site because the infrastructure of the two land areas was different. The areas that were composed of original land were more strongly set in their structure. Any new building that would be built on that land would be more likely to occupy the same land as the building before it. The lack of uniform leveling would discourage a building from building outside the footprint of the original building. By contrast, the filled land provides a blank canvas for changing around the buildings. All of the filled land is of generally equal quality. The way the earth of this site has been shaped has been crucial in its development.
Air
With the site’s close proximity to the Charles, most of its streets receive fairly constant wind blowing straight down them. Wind flows south, down Massachusetts Avenue and continues down each of the streets as it reaches them. The streets themselves generally have a good flow of fresh air through them. Where the air flow becomes interesting is within the alleyways. One particularly interesting flow is contained in the alley off of Massachusetts Avenue and Marlborough.
In this alley, there are only two entrances, yet the wind flows distinctly inward through both of them. This creates a very interesting flow through the open spaces in the alley, with a quite distinct pattern. The diagram below shows a sketch of the flow within the alley.
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Air
flow diagram of alley. Drawn by noting the path of breath in cold air
at each point.Because of the bizarre shape of this alley, the air enters and ends up creating a swirling pattern toward the south end. This is more than just an oddity though, the low pressure systems created around the edges and in the center of this whirlwind have many effects on the alleyway. First, snow and refuse are both deposited toward the edges. Second, the continual flow of air and the lack of sun keep temperatures at the edges low, allowing snow to stay longer. The center of the whirlwind can be seen (and shown to not be a temporary occurrence) by the deposits of debris where the “X” is in the flow diagram.
 Trash
and snow at outer edge of flow |
 Deposited
debris (weeds mostly) at center of flow. |
 Snowdrift
at end of alley |
Another problem that this system causes that is of slightly more pressing importance is the trapping of polluted air. The combination of these wind patterns and the lack of sun can create temporary inversions, keeping pollutants in the alley. As Anne Whiston Spirn discussed in The Granite Garden, “A local inversion may form at the bottom of a shady street canyon in the morning, trapping the exhaust from rush hour traffic at breathing level. Unless dissipated by winds, the inversion persists until the midday sun reaches the street and warms the surface air at ground level” (2). Also, due to the whirlwind created, smoke from chimneys seems to be pulled down into the alley. This is shown by the discoloration on the brick of some of the older buildings in the alley. (They are believed to be old because they were definitely built before telephone wires were run through homes). The combination of all of these factors makes the environment in this alley quite bad, all due to the air flow patterns.
 Diagram
of pollutants being pulled down into a street canyon. |
Brick shows dark discoloration due to air. |
Water
One of the single greatest factors in the sites development over time has been water. The flow of water is seen in both small examples such as rainwater runoff, and large examples like the end of the Fens designed to keep the area from flooding.
 Parking
lot with extra drain and ice damage |
Because much of the site is sloped toward the Charles, areas on the north end of the site receive far more water after storms. The parking lot at left is a good example of this. It lies on the far north end of the site and thus receives a disproportionate amount of runoff. So much more water flows there than was expected by the builders that they had to put in a second drain to the low point of the lot. This particular lot also shows evidence of damage to the asphalt due to water. When all of that water gathers at the low point near the drains, some of it gets in the gaps in the asphalt and freezes, cracking the lot. In planning the parking lot, the builders only figured on the amount of water their lot would gather in a storm. They forgot to include the natural flow of water in the area.
 Cemented
drain. Now the area just floods. |
This seems to be a common theme throughout the site; lack of proper planning for drainage. It seems that many planners in the area have built many projects without considering the natural tendency of the area to gather water. In the case on the right, the drainage was properly planned for when the building was first constructed, but when the storm sewer system changed years later, it was plugged and never replaced. The result is a low-lying area in an alley that fills to about 6-inches of water whenever it rains. An example of the fact that even good planning in the past cannot make up for poor planning in the present.
 Melted
ice showing the Charlesgate linkage between the Fens and the Charles. |
A major part of what contributed to the development of the site was the Charlesgate portion of the Fens, (so named because it was the tide gate into the Charles). Part of the brilliant “Emerald Necklace” park plan of Frederick Law Olmstead, it provided drainage for the area and added an element of nature to the surroundings that helped the area to gain popularity and grow. When the river has ice on it, one can see exactly where the Fens empties into that Charles. Because of the flow of water into the river, it melts the ice around it as seen in the figure at left.
Today, much of the Fens has fallen into decline. There is currently construction to revive it with improvements at many strategic points. The Muddy River Restoration Project hopes to turn the Fens back into much of what it used to be. The Charlesgate Dredging portion of the project is currently going on in the site.
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(3) - The Muddy River Project |
 Sign
for Charlesgate Dredging |
Life
 A
bird in the bush. (Worth 1/2 in the hand). |
Animal life is not often seen in the heart of the city. Aside from vermin and pigeons, very few wild animals live in the busy parts of the city. Going a little farther out toward the edges though, will reveal quite a bit of animal life. Much of the animal life on the site revolves around the main bodies of water. Because there is less human interaction and an abundance of water, most animals on the site are found along the eastern and northern edges of the site. Birds can be seen gathering on a tree near the Charles, and the remnants of an animal’s home in a tree hollow can be seen near the Charlesgate.
 An
abandoned tree hollow near the Charlesgate. |
There are not many animals in the immediate vicinity though. One very likely reason is the current construction progress on the Muddy River Project. The Charlesgate Dredging is not an animal-friendly endeavor and most of the species have probably fled. The hope though is that when the project finishes, more animals will return.
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Trees however, are a far different story. Trees are abundant throughout the site, but each one’s health and foreseeable future is different. In some locations within the site, trees have been planted thoughtfully and have been adequately planned for. In others, it looks almost as if the tree was planted right into the wet cement of the sidewalk. In the case of the trees running along the Massachusetts Avenue side of the site, (picture right), it mirrors the words of Spirn in The Granite Garden, “Instead, current practice aggravates already hostile conditions. Downtown streets are entirely paved from building wall to building wall. Trees are planted in tiny pits. Pavement waterproofs the ground surface and permits neither air nor water to reach tree roots below” (4).
 Trees
in front of the Charlesgate condominiums with plenty of space. |
The Massachusetts Avenue trees stand in stark contrast to the trees along the front of the Charlesgate condominiums. These trees were set out, away from the building, with large planters and rich soil. The sides of the planters are also raised so that soil is not washed away by flow of rainwater. In this case, the landscape architect was thinking ahead and realizing that water flows over much of this area. Right across the street at the Charlesgate itself, a group of trees grows in a healthy family. Not very closely tended, but left with great resources and space at their disposal, they have flourished.
 Spacious
planters at the Charlesgate condominiums |
 Trees
in a family at the Charlesgate |
Conclusion
Clearly natural processes shape cities from their inception to their demise. The more interesting point to note though is that cities also shape natural processes. This is seen most clearly in the case of the Back Bay Fens. It was a huge project which changed the whole environment of the area, but did so in a cunning harmony with nature. The processes of nature have not opposed the Back Bay because it was done in concert with them. But the forces of nature show time and time again that they will bring down any project that is not thoughtfully in tune with them. Nature continues to be a formidable foe, but only if fought.
Works Cited
(1) The
Boston Atlas. http://www.mapjunction.com/places/Boston_BRA/main.pl?ht=768
(2) Spirn, Anne Whiston. The Granite Garden. P. 56-57.
(3) The Muddy River Project.
http://www.muddyriverproject.org/
(4) Spirn, Anne Whiston. The Granite Garden. P. 176.
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Seriously... is that not amazing? |
Grant Jordan '06 -- 2003