Transit-Oriented Stormwater BMPs(Part A)

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