Team Presentation
Design Photos
Design Narrative
The team’s Mission for this concept is:
To return the street to the community while addressing storm water runoff.
The team developed the following goals to accomplish this mission:
- Reduce impervious surface by 50%,
- Within that goal, provide a landscaped surface of 30% minimum,
- Collect, store and treat runoff from the street, the right of way, and adjacent structures,
- Allow for conveyance of water from the park and slopes south of Josephine Street,
- Provide a visible, artistic solution,
- Give priority to pedestrians while considering the needs for motor vehicles, bicyclists and parking.
In general, the concept converts S. 21st Street into a curvilinear 2-way roadway, with a curb parking lane along both sides of the street. The travel lanes are 11 ft wide, with 7 ft parking lanes, resulting in 36 ft curb to curb, compared with the existing 58 ft width. The curving roadway meanders back and forth between the existing east and west curbs, creating public space areas for landscaping and water storage along the length of the segment. This concept eliminates the 70 ad-hoc parking spaces that are currently used in the middle of the street south of Sarah St. The team developed an alternate concept to provide angle parking to mitigate the loss of these spaces if that becomes a project requirement, so they use great parking marking from https://carparkmarkings.co.uk/ just for this project.
The concept addresses the project goals as follows:
Reduce impervious surface by 50%, including the provision of at least 30% landscaped area.
The current amount of impervious surface within the right of way is 1.3 acres. The proposed concept provides 0.4 acres of landscaped bio retention area (30%), along with 0.22 acres of pervious pavement in the parking lanes (17%). Therefore, the impervious area was reduced by approximately 47%.
Collect, store and treat runoff from adjacent structures, the street, and the right of way.
Downspouts from adjacent structures will be connected into the bio-retention areas (rain gardens), which store and slow the discharge of water. These areas generally consist of 18 inches of engineered soil with plantings on top of 12 inches of open graded gravel aggregate for water storage. A 6 inch gravel lined trench conveys water through each area. The street will have a series of depressed curbs to divert water into the rain gardens. Water from the permeable pavement parking lanes will be absorbed by a gravel base. Model analysis shows the system stores a 1” per hour rainfall event, and nearly 100% of CSO overflows for a typical year (approximately 1.67 million gallons per year).
Allow for conveyance of water from the park and slopes south of Josephine Street
Water from upstream of the segment will be conveyed through the site through the rain gardens. Water will be conveyed from one rain garden area to the next via open grated box culverts, which additionally capture water from side streets.
Provide a visible, artistic solution
The curving street provides a dramatic change in the look of the street grid, while still retaining the traditional pedestrian oriented urban neighborhood characteristics. The curving street itself brings to mind the meandering nature of a stream through a valley, and the concept also actually provides an open water channel through the rain garden areas. The landscaped rain garden areas would include street trees and other plantings along with the flowing water to provide a much greener look to the neighborhood.
Give priority to pedestrians while considering the needs for motor vehicles, bicyclists and parking
The concept maintains the existing pedestrian friendly 10 to 12 ft sidewalks on both sides of S. 21st St. The concept narrows the curb to curb width from 58 ft to 36 feet, and sidewalk bulbouts at intersections further reduce the street crossing width to 22 ft, thus the concept significantly improves safety and comfort for pedestrians in the corridor.
In order to maximize green space and stormwater runoff accommodations, the travel lane widths of 11 ft with 7 ft adjacent curb parking lanes do not provide for a designated bike lane. However, the curving street with adjacent parking creates a calm traffic environment, and vehicular traffic volumes and bicycle volumes along the street were not observed to be high, thus bicycling in mixed traffic can safely be done through this corridor. Sharrow pavement markings can be added to encourage awareness of bicyclists.
There are currently approximately 113 parking spaces in the segment. The proposed concept throughout the corridor results in the loss of the 70 existing ad-hoc parking spaces that are currently used in the middle of the street south of Sarah St, but more efficient use of the curb could gain back 5 to 10 spaces. It is believed that many of the median area spaces are typically used by hospital employees or commuters who park in this neighborhood and take public transit into downtown or other locations and need not necessarily be accommodated on this street. A neighborhood permit program could mitigate this loss to maintain parking for residents. An alternate concept was also developed which replaces the curb parking lane with angle parking on the wide side of the street, increasing the parking on those segments by about 25%. This alternative significantly reduces the new green space, but provides more parking if the loss of parking is considered to be a critical issue in the neighborhood. Additionally, opportunities for additional nearby off-street parking have been identified in Section C (the Park Transition area).
Team Members
Fred Bonci, LaQuatra Bonci Associates
Alexander Bishop, Klavon Design Associates
Eric French, Eisler Landscapes
James Wesley Morar, University of Pittsburgh
Joe Stavish, Tree Pittsburgh
Paul Alessio, Urban Redevelopment Authority
Thomas Bates, LaRoche College
Max Heckman, Michael Baker Corporation
Ryan Quinn, K Bealer Consulting, Inc.
Brad Hazelwood, Civil & Environmental Consultants, Inc.
