Final concept shared on 21st Street design
October 10, 2017
A meeting to share the final streetscape and green infrastructure design concept for South 21st St. in an effort to address excessive stormwater was held on Sept. 19 at the Brashear Center.
Representatives from Environmental Planning & Design (EPD), Groundwork/Civil (GC), Western Pennsylvania Conservancy (WPC), Pittsburgh City Planning and Pittsburgh Water and Sewer Authority (PWSA) were present to detail the plan and answer questions.
The project area is a four-block area from East Carson St. to Josephine St.
The issue is a stormwater management problem resulting in poor water quality, illicit discharges, surface flooding, basement sewage flooding, and more.
The approach will be green infrastructure, a cost-effective tactic that uses vegetation, soils, and other elements and practices to restore some of the natural processes required to manage water and create healthier urban environments.
The benefits of a clean and green strategy include local flood mitigation, increased property values, air pollution and carbon reduction, improved water quality, and more.
Overall pedestrian safety would be enhanced as travel lanes are narrowed. The planned meanders in the plan will also increase safety, Jayson Livingston of EPD said.
The plan includes weirs, or structures that help retain water, at every major intersection.
There would also be medians with trees, green planters for storage, new sidewalks, underground components, and more throughout the corridor.
As part of the project, Pittsburgh City Planning undertook a parking analysis of 21st Street. Currently, there is a mix of metered, permit and unregulated parking in the corridor.
The plan decreases the number of parking spaces to 43 from the current 103 spaces, with most of the losses being unregulated parking spaces.
Unregulated parking in the middle of the street and under the overpass at Josephine St. would be removed as the medians are installed. There would be no parking provided along the new medians. Parking would be permitted along the curb line.
Reverse diagonal parking areas would be installed so when motorists pull out it is safer for bicyclists and pedestrians.
The travel lanes and parking areas will meander, or curve, to allow for wider sidewalks; move planting areas out from power lines; and for visual enhancement.
The plan has been vetted by City Planning.
“This layout is the final concept,” civil engineer Art Gazdik of GC said.
The goal is to produce a plan by year’s end. Fundraising has begun. If successful, the project could begin in 2018. Maintenance would be included in the budget.
Implementation of the project requires acquisition of those funds, which will be sought from the city, grants, and foundations.
The goal is to keep rainwater out of the system. The most effective means is focusing efforts on the sheds that contribute the most to the system. The top 30 sheds were identified, with six priority sheds chosen.
One of those sheds is the 21st Street area, designated M-16. In a typical year, M-16 has 61 occurrences, or 434 hours, of storm water overflow totaling 10.2 million gallons of combined sewage and storm water.
The idea is to convey the water from South Side Park. The goal is to capture the water and build a system that collects it as it runs off and sends it to devices (features that will slow it) to delay the flow.
The capture goal is to provide onsite control for a rainfall event of 1.5 inches in a 24-hour period. The total annual capture for the project is estimated at 4.2 million gallons.
Building on a 2014 visioning process with a 21st Street design charrette, the streetscape project will have a heavy focus on green infrastructure with both underground and above ground components.
The goal is to keep 85 percent of the storm water out of the sewers using a variety of landscaping elements including trees, bioswales and storage tanks.
With more development in the city, there has been more storm water run-off and more impervious surfaces resulting in more spikes of overflow. Other problems, such as poor water quality and flooding also result from storm water not being managed the way it should be.
There will be no cost to residents in the project area. For instance, the majority of the sidewalk will be removed and replaced, with no cost to homeowners.
“We don’t usually ask people for anything but cooperation,” Mr. Livingston said.