1
December 2011
Transit-Oriented Stormwater Management 41st - 50th & Spruce - Market Ann-ariel vecchio, Mit, master in city planning ‘12 stephen kennedy, Mit, Master in city planning ‘12
11.314 water, landscape, & urban design
2
December 2011
Project Outline 01
Design process
02
site analysis: hydrology
4-8
built environment
9-15
Transportation 03
3
16
Watershed design conceptual diagram
17
green transit corridor
18
Market Street
19-21
Bus Stops / Streetscape
22-24
Parking Lots
25-27
04
Greened Acres Evaluation
28
05
Implementation & Management
29
06
conclusions
30
Appendices
32
PUBLIC REALM
INSTITUTIONAL REALM
LINEAR / DIRECTIONAL
POLYGON / CORNER
Design Process
MULTIDIMENSIONAL
ALLEYS
SPATIAL CONDITIONS
WIDE
NARROW
LINEAR / DIRECTIONAL
PRIVATE REALM
ELONGATED
POLYGON / CORNER
OPEN SPACES
PARKING LOTS
STREETS WIDE
Through 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).
RECTANGULAR
MULTIDIMENSIONAL
ALLEYS
SMALL
LARGE
WIDE
NARROW
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.
NARROW
ELONGATED
RECTANGULAR
OPEN SPACES
In this area, we identified specific opportunities and began to develop concepts for stormwater management that combined different typologies or approaches.
PARKING LOTS
SMALL
LARGE
WIDE
SCHOOLS
NARROW
BUSINESSES
LARGE
HOMES
SMALL
SCHOOLS LARGE
3 Further documentation of the design process is included in the appendices.
PRIVATE REALM STREETS
EEN OGRAMS NCEPTUAL AMEWORK
NSTITUTIONAL REALM
SPATIAL CONDITIONS
GREEN PROGRAMS CONCEPTUAL FRAMEWORK
LARGE
SMALL
BUSINESSES SMALL
LARGE
HOMES LARGE
SMALL
LARGE
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.
x N
0 100
400
4
600
MARKET ST
x CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
x
x
x
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
x x
02
site analysis hydrology
Elevation above sea level
x
100’
Heightmap Topography
The Neighborhood’s low-lying areas clearly illustrate the presence of mill creek’s buried flood plain. high Points low Points
2’ Contours
x
40’
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.
x N
0 100
400
5
600
MARKET ST
x CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
x
x
x
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
x x
02
site analysis hydrology
Elevation above sea level
x
100’
Topography Lightmap
high Points low Points
2’ Contours
x
40’
Clear point of subsidence at the cvs parking lot in the brightest point in our sewershed.
N
0 100
400
6
600
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
02
SEWERSHED
CONTOURS (2’ INTERVAL)
SEWER MAIN
SECONDARY SEWER LINE
site analysis hydrology
The Municipal Drainage System
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.
primary flows
N
0 100
400
7
600
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
CALCULATED SURFACE FLOWS
02
site analysis hydrology
Calculated Flows
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.
primary flows
N
0 100
400
8
600
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
02
site analysis hydrology
Sewer Inlets
A b
subsistence at farragut & sansom Pooling on Farragut st.
578
Inlets in neighborhood
19
Intersections with more than four inlets Indicate 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.
A
b
N
0 100
400
9
600
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
02
site analysis Built Environment
Total Area
9,700,000
sq ft
222 Acres
N
0 100
400
10
600
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.
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
02
site analysis Built Environment
Impervious data from philadelphia water dept
/ city of philadelphia
Impervious
Pervious
170 acres
52 acres
77%
23%
N
0 100
400
11
600
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
Impervious 02
site analysis Built Environment
Streets
35.7 acres
21%
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.
N
0 100
400
12
600
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.
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
Impervious 02
site analysis Built Environment
Sidewalks
Pervious
35.7 acres
20.4 acres
21%
12%
N
0 100
400
13
600
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.
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
Impervious 02
site analysis Built Environment
Buildings
Pervious
35.7 acres
20.4 acres 54.4 acres
21%
12% 32%
N
0 100
400
14
600
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.
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
Impervious 02
site analysis Built Environment
Parking
Pervious
35.7 acres
20.4 acres 54.4 acres
54.4 acres
21%
12% 32%
10%
N
0 100
400
15
600
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.
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST
50 th ST FARRAGUT ST
Impervious 02
site analysis Built Environment
Pervious
Pervious
35.7 acres
20.4 acres 54.4 acres
54.4 acres
52 acres
21%
12% 32%
10%
23% Public Open Space Private Open Space Vacant Lots
N
0 100
400
16
600
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.
MARKET ST
CHESTNUT ST
41st ST
SANSOM ST
WALNUT ST
LOCUST ST
SPRUCE ST LOCUST
50 th ST FARRAGUT ST
02
site analysis transportation
Public Transit
Market21 Bus Frankford Elevated Rail Line to subway
Penn’s Landing To 69th Street Transportation Center
31 Bus
64 Bus
City Hall To 76th-City
49th-Parkside To Pier 70