transit-oriented stormwater bmps(part a)
DESCRIPTION
Design Process & Site AnalysisTRANSCRIPT
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Transit-Oriented Stormwater Management
December 2011
11.314 water, lanDscape, & urban Design
Ann-Ariel vecchiO, mit, master in city planning ‘12STephen kennedy, mit, master in city planning ‘12
41st - 50th &spruce - market
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projectOutline01
02
03
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05
06
site analysis:
green TrAnSiT cOrridOr
cOncepTuAl diAgrAM
18
greeneD acres evaluation 28
implementation & management 29
conclusions
appenDices
30
32
Design process 3
hydrOlOgy 4-8
MArkeT STreeT 19-21
builT envirOnMenT 9-15
buS STOpS / STreeTScApe 22-24
TrAnSpOrTATiOn 16
pArking lOTS 25-27
watersheD Design
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December 2011
LINEAR / DIRECTIONAL
PRIVATEREALM
POLYGON /CORNER
SPATIAL CONDITIONS
MULTI-DIMENSIONAL
STREETS
WIDE NARROW ELONGATED RECTANGULAR
ALLEYS
INSTITUTIONALREALM
PUBLICREALM
GREEN PROGRAMSCONCEPTUAL FRAMEWORK
OPEN SPACES PARKING LOTS
SMALL LARGE
BUSINESSES
SMALL LARGE
SCHOOLS
LARGE
WIDE NARROW
HOMES
SMALL LARGE
LINEAR / DIRECTIONAL
PRIVATEREALM
POLYGON /CORNER
SPATIAL CONDITIONS
MULTI-DIMENSIONAL
STREETS
WIDE NARROW ELONGATED RECTANGULAR
ALLEYS
INSTITUTIONALREALM
PUBLICREALM
GREEN PROGRAMSCONCEPTUAL FRAMEWORK
OPEN SPACES PARKING LOTS
SMALL LARGE
BUSINESSES
SMALL LARGE
SCHOOLS
LARGE
WIDE NARROW
HOMES
SMALL LARGE
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design processthrough the analysis of the site, we identified a series of typologies that characterize and organize different physical attributes and potential opportunity sites within the project area. they are: linear (streets and alleyways), polygons (open spaces and parking lots), and multidimensional (schools, businesses, and homes).
mapping the typologies within the project area revealed a concentration and convergence of these types along the main sewer line, which is also the buried floodplain of the mill creek.
in this area, we identified specific opportunities and began to develop concepts for stormwater management that combined different typologies or approaches.
after sharing these ideas with project teams working in other areas within the mill creek watershed, it became evident that many of the conditions or typologies within our project site are present across the mill creek watershed. however, the presence of transportation infrastructure, public transit, and parking make the spruce to sansom sewershed unique. since other teams elaborated similar ideas to those in our initial concepts for stormwater management, we chose to focus on the unique characteristics of the project area. the following presents analysis of the project area and our proposal for a transit oriented stormwater management approach.
Further Documentation oF
the Design process is incluDeD in the
appenDices.
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heightmapTopography
02 site analysishydrOlOgy
100’
40’
elevation above sea level
the neighborhooD’s low-lying areas clearly illustrate the presence oF mill creek’s burieD FlooD plain.
the low points above were most likely part oF the mill creek beD, about 3/4 oF a mile From the creek’s mouth at the schuylkill river.
high points
low points
2’ contours
x
x
xxx
x
x
x
x
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MARKET ST
CHESTNUT ST 41st st
WALNUT ST
SANSOM ST
LOCUST ST
SPRUCE ST
50th St
FARRAGUT ST
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Topographylightmap
02 site analysishydrOlOgy
100’
40’
elevation above sea level
clear point oF subsiD-ence at the cvs parking lot in the brightest point in our sewersheD.
high points
low points
2’ contours x
x
x
xxx
x
x
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CHESTNUT ST 41st st
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LOCUST ST
SPRUCE ST
50th St
FARRAGUT ST
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The Municipal drainage System
02 site analysishydrOlOgy
primaryFlows
sewersheDs
the philadelphia water Department uses sewersheds to define primary flows to the municipal drainage system. however, to understand the true drainage patterns in a watershed, one needs to look beyond these engineered boundaries.
sewersheD
sewer main seconDary sewer line
contours (2’ interval)
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CHESTNUT ST 41st st
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calculated Flows
02 site analysishydrOlOgy
primaryFlows
DeFining area Drainage
calculating stream flows highlights the characteristics of the watershed. Following these flows, it is evident that surface water in the neighborhood drains to the site’s center along the sewer main.
this demonstrated that multiple sewersheds converged toward our original sewershed.
calculateD surFace Flows
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Sewer inlets
02
19
578
site analysis
intersections with more than Four inletsindicate under sized or non-functional inlets, high volume, or drainage from all directions. a reduction in the total volume of water flowing to these inlets is an important objective.
inlets in neighborhooD
hydrOlOgy
aa subsistence at Farragut & sansom b
b pooling on Farragut st.
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CHESTNUT ST 41st st
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FARRAGUT ST
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Total Area 222 Acres
02 site analysisbuilT envirOnMenT 9,700,000 sq Ft
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CHESTNUT ST 41st st
WALNUT ST
SANSOM ST
LOCUST ST
SPRUCE ST
50th St
FARRAGUT ST
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impervious
02170 acres
site analysisbuilT envirOnMenT
77%
impervious pervious
23%52 acres
the built environment’s impact on Drainage
the high amount of impervious, or paved, surfaces in this area creates a large volume of water that flows directly into city
sewers and, eventually, into the schuylkill river. however, this also indicates that the implementation of stormwater management
bmps has huge potential to reduce sewer overflow events. the following pages of land cover analysis describe the components
of these impervious surfaces.
data from philadelphia water dept / city of philadelphia
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CHESTNUT ST 41st st
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FARRAGUT ST
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Streets
02 site analysisbuilT envirOnMenT
21%
impervious
35.7 acres
pervious
streets are a significant proportion of impervious surface and are found throughout the project area. Due to their linear form, interventions in parking lanes and other areas along the street edge have the potential to capture water before it flows into sewer inlets on each block.
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Sidewalks
02 site analysisbuilT envirOnMenT
21%35.7 acres
12%20.4 acres
impervious pervious
although sidewalks make up a smaller proportion of impervious surface, their location adjacent to streets creates the opportunity
to develop interventions that can treat run-off from multiple locations – streets, sidewalks, and homes. in addition, stormwater
management bmps can also be designed to improve the pedestrian environment and improve the public realm. in the
project area, the width of sidewalks (sometimes as wide as 17’) along east-west streets, such as market, chestnut, and walnut,
provide ample space for visible bmps that can provide multiple benefits.
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buildings
02 site analysisbuilT envirOnMenT
32%21%35.7 acres
12%20.4 acres 54.4 acres
impervious pervious
buildings represent a proportion of impervious surfaces almost equal to streets and sidewalks combined. therefore, individual
action on private property is also significant. however, since most buildings are small in size, a stormwater management strategy
that addresses buildings requires the participation of many individuals. on many blocks along the sewer line, large-footprint
buildings are often adjacent to open areas and parking lots.
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parking
02 site analysisbuilT envirOnMenT
10%32%21%35.7 acres
12%20.4 acres 54.4 acres 54.4 acres
impervious pervious
parking lots represent 10% of the project area. while they range in size from small residential lots to larger lots that service
commercial areas, the large lots cluster along the main line of the sewer system, which is also the buried flood plain of the mill creek. these large plots of land also lie at low points in
the project area and present the potential to remove significant amounts of impervious surface or site other bmps.
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pervious
02 site analysis
public open spaceprivate open space
vacant lots
builT envirOnMenT
10%32%21%35.7 acres
12%20.4 acres 54.4 acres 54.4 acres
impervious pervious
23%52 acres
the site features a significant amount of pervious area, including public open space as well as private spaces in block interiors and under utilized vacant lots. much of the pervious surface could be
improved to function as green stormwater infrastructure while providing aesthetic benefits in the public realm.
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public TransitMarket-Frankford
21 bus 31 bus 64 bus02 site analysis
elevateD rail line to subway
penn’s lanDing to 69th street transportation center
city hall to 76th-city
49th-parksiDe to pier 70
TrAnSpOrTATiOn
in addition to the natural hydrological system and built environment, several public transit lines cross
through the project area. transit stops define nodes that neighborhood residents use on a daily basis.
bus stops often coincide with the location of inlets at low points on many blocks.
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CHESTNUT ST 41st st
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LOCUST ST
50th St