Green Roof Tour at Pittsburgh Zoo

On October 16, 2013, Jim Pashek joined old friends on a “Rooftop Rendezvous at the Zoo” sponsored by Green Building Alliance.  Jim was involved with project management of the “New Zoo” beginning in the early 1980’s and had the pleasure to work over the years with our tour guides that night, Frank Pizzi and Marjorie Marks.

Zoo Rooftop Garden - Extensive Plantings

What a spectacular demonstration rooftop garden.  About half of the planted roof area is an “extensive” roof garden with 3-4 inches of special soil mix.  The other half was this lush “intensive” rooftop garden of plants placed in a special soil mix ranging from 3-36 inches.  You can tell from the photos that they have been successful to identify species that can thrive in a very hot micro climate and in very shallow soils. 

Carex pennsylvanica

The garden got me thinking that the rooftop garden at Pashek Associates is ready for an overhaul.  This “extensive” garden is planted in trays on 4 inches of special soil mix.  We decided to try four varieties of sedums to see which would survive in very difficult site conditions.  They all survived and have never been watered since after the first growing season.

Some plants that we may plant include Carex pennsylvanica (the small grass clump like plants), which is one of the few sedges that tolerates very dry conditions.  I find it interesting that I would normally use Carex P. in part to full shade but at the Zoo, it is doing great in full sun.  I also think we will try in our rooftop garden Schizachryium scoparium, a plant that is home on the prairie and thrives in hot, dry, well drained conditions (the typical rooftop garden).

Schizachryium scoparium

Frank, thank you for a very informative presentation and tour of the Zoo’s rooftop garden gem.  Thanks also to the GBA for arranging the tour.  We look forward to another rooftop garden tour sponsored by GBA in November at the Convention Center, a green roof designed by Pashek Associates and installed by Eilser Nurseries.  Maybe next summer we will have more pictures of our newly renovated rooftop garden at Pashek Associates.  Please stop in and ask for a tour of our garden here on the Northside.

County Building Green Roof Measures its Own Effectiveness

You may think of the Allegheny County Office Building, 452 Forbes Ave., Pittsburgh, as the place to go if you have a question about your property assessment.

But this historic building is also the site of a beautiful, functional and productive green roof, designed with the help of Pashek Associates. Green roofs benefit the local environment by reducing storm water runoff; keeping buildings warmer in winter and cooler in summer; evening out daily temperature swings; and helping to mitigate the heat island effect.

The County Office Building green roof, completed in 2010, is now growing into its role as a powerful tool for protecting the environment.

A network of sensors embedded in the soils monitor performance of this roof compared with a conventional “control” roof. The sensors measure roof temperature, soil moisture, water flow and water retention, with data collected every 15 minutes. Over time, this information will demonstrate the valuable role that green roofs can play in easing some of the damaging effects that development has on our environment.

Here is an example of the data that can be seen by visiting the monitoring website. This example compares temperatures in a one-month period on the control roof (top line) with temperatures recorded by two sensors on the green roof (bottom two lines).

The green roof includes four different types of growing conditions, and over time it will also be possible to learn through the monitoring system how each type performs compared with the others. They are:

1. Intensive – 8 to 12 inches of soil and growing shrubs and plants needing the soil depth.
2. Semi-intensive - 6 inches of soil and able to grow plants and shrubs.
3. Roll out Mat – set on 4 inches of soil, this pre-grown sedum mat provides instant cover.
4. Tray system – easy to install, pre-grown sedum and lightweight.

A Green Roof for a Green Convention Center

The Gold LEED Certified convention center in Pittsburgh is becoming even greener.  This fall, a green roof is being constructed above the loading dock and is fully accessible to event goers. 

In the summer of 2010, as planning and design was being completed for fixing a roof leak, the Sports and Exhibition Authority realized they had a golden opportunity to install and showcase a green roof that is readily accessible from meeting rooms on the third floor. 

Pashek Associates was hired to design the new roof to include outdoor gathering and event space along with planting areas.  The final design includes a meandering blue pathway resembling a stream, keeping with the theme of the existing architecture and meant to remind visitors of the green roof’s stormwater benefits.  The path separates two contrasting types of planting areas.  The first is a typical sedum planting done on most extensive green roofs.  The second consists of native perennials, providing wildlife habitat.  The simplicity of the design allows the building’s sculptural cable bundles to remain a focal point.

 Stay tuned for photos of the ongoing construction to be completed this fall!

Permaculture, Community Revitalization, and Sustainable Design

A small, but growing, group of neighbors in East Liberty, called the Borland Garden Cooperative, have come together in order to develop a sustainable, multi-purpose urban garden that eliminates vacancy, adds vibrancy and biodiversity, and serves as an educational tool and community gathering space.   

Funded by the Community Design Center of Pittsburgh, Sprout Fund, and the Sarah Heinz Foundation, the Borland Garden Cooperative partnered with East Liberty Development Incorporated, Pittsburgh Permaculture, and GTECH Strategies to develop a unique urban garden model.  Pashek Associates was hired to develop a master plan for the garden in which energy and water will be captured, materials will be recycled and reused, and everyone who works in the garden shares tools and the harvest.

The group envisions the garden as a place in which the surrounding community can come together to learn, share resources, work together, grow together, and share in the bounty.  Some of the unique features of the garden include an urban food forest, traditional vegetable garden, water cistern, bio-shelter, rain gardens, chicken coop, outdoor kitchen and gathering space, and a labyrinth.   

Chimney swift habitat helps offer pest management as well as doubling as educational signage.  A windspire serves as a sculptural focal point as well as powering lighting.  Bee and butterfly habitat promotes pollination within the garden.  A sensory garden entices the public to walk up to, smell, touch, taste, see and interact with the garden.  Compost bins help recycle chicken manure, garden waste, as well as compostable materials from adjacent neighbors. 

The master planning process is almost finished but that does not mean the work is done.  The Cooperative will be out in full force to prepare for the installation of the rain gardens, cistern, street trees, and urban food forest in the fall. 

DCNR's Stormwater BMP Guide for Parks

The Pennsylvania Department of Conservation and Natural Resources has recently asked us, along with some other LA's in the State, to review and comment on their new Stormwater BMP Guide for Parks.  The guide is for grantees to use and apply to their sites.  Below is the final version:

Rain Garden- an excavated shallow surface depression planted with specially selected native vegetation to treat and capture runoff.  Rain gardens should be located in well-drained soils.  They allow stormwater to be absorbed by plants and infiltrated into the groundwater. 

How can you apply this in your park?  A simple rain garden can be located near a walkway, parking lot, court area, or other paved surface to absorb stormwater runoff.  Native vegetation that thrives in wet conditions should be planted to enhance the water absorption capabilities of the rain garden.   Additional benefits of native vegetation may include creating habitat areas for wildlife and birds and aesthetic enhancement of the site. This type of design is inviting to park visitors and educational signage can illustrate how a simple rain garden design can be created at home to reduce stormwater runoff.

Pervious Pavement- consists of a permeable pavement (surface course) underlain by a uniformly-graded stone bed which provides temporary storage for stormwater runoff and promotes infiltration.  The surface course may consist of porous asphalt, porous concrete, or various porous structural pavers laid on uncompacted soil. 

How can you apply this in your park?  Pervious pavement can be used in parking areas, on basketball and tennis courts, for trails and walkways, etc.  Use of pervious pavement is not practical for wooded or flood prone areas due to sediment and leaf-litter filling the porous voids of the pavement.   In open areas, use of pervious pavement provides the added benefit of managing stormwater beneath the surface, minimizing disruption of additional areas for the management of stormwater and the costs associated with construction of a stand-alone stormwater management facility.  For large parking lots consider a mix of surface types that include turf parking with a gravel base, aggregate paving for traffic aisles, and pervious paving for parking stalls.

Riparian Areas- a permanent area of trees and shrubs located adjacent to streams, lakes, ponds, and wetlands.  Riparian forests are the most beneficial type of buffer for they provide ecological and water quality benefits. 

How can you apply this in your park?  Enhance the areas adjacent to rivers, streams, wetlands and ponds with native vegetation or create a “no mow zone” with meadow grasses that is at least 35’ wide on all sides.  Be sure to include public access points where appropriate so park visitors can enjoy these water resources.  Interpretative signs can describe the benefits of riparian areas and describe the wildlife habitat areas created.

Vegetated Swale- a broad, shallow channel densely planted with a variety of trees, shrubs, and/or grasses.  Vegetative swales should be promoted in lieu of storm piping to convey stormwater naturally, promoting infiltration, reducing runoff volume, and filtering pollutants.   

How can you apply this in your park?  A vegetated swale is an economical alternative to storm piping and may be constructed between a street, parking lot or commercial/industrial area and the park to provide a natural stormwater infiltration area.  The park can become a solution to an urban stormwater issue.

Naturalized Infiltration Basin- an earthen structure constructed either by impoundment of a natural depression or excavation of existing soil that provides temporary storage and infiltration of stormwater runoff. 

How can you apply this in your park?  Existing and new stormwater management basins can be naturalized with native plantings to aid in faster infiltration and to provide wildlife habitat.  Basins can be planted with native wildflowers and warm season grasses that are attractive and low maintenance. 

Floodplain and Wetland Restoration- tries to mimic the interaction of groundwater, stream base flow, and vegetative root systems- key components of a stream corridor under pre-settlement (pre-1600s) conditions.  The interaction among these elements provides multiple benefits, including the filtering of sediments and nutrients through retention of frequent high flows on the floodplain, removal of nitrates from groundwater, reduction of peak flow rates, groundwater recharge/infiltration, reduced erosion, control non native invasive species, and an increase of storage and reduction of flood elevations during higher flows. 

How can you apply this in your park?  Floodplains should remain natural without constructed facilities; however low-impact accessible paths may be included to invite park visitors to walk among native vegetation and view wildlife.    Existing wetland should be protected and restored to enhance their ecological benefits such as increasing water quality, reducing stormwater impacts, and providing critical habitat for a variety of species.  Boardwalks and viewing decks can provide access to wetland areas for environmental education.  Educational signage can be installed to teach park visitors the critical role floodplains and wetlands play in the environment.

Reforestation- replant the site with trees. 

How can you apply this in your park?  Reforestation can occur in both natural areas and developed areas of a park.  Riparian corridors, floodplains, wetlands, meadows, and forest edges can all benefit from reforestation.  Reforestation and planting of trees near picnic areas, pavilions, spectator areas, playgrounds, benches, trails, and  other built features will enhance the environment, provide shade, and create a sense of place within a park.

Extensive Green Roof- the most popular green roof for smaller structures and existing structures.  Its lightweight attributes minimize the amount of structural changes needed to create it.   

How can you apply this in your park?  Extensive green roofs may be constructed on park kiosks, pavilions, environmental education centers, sheds and community recreation centers.

Warm Season Meadows- conversion of a turf area into a meadow.  Native species should be selected for their minimum need of fertilizers, herbicides and pesticides.  Minimize mowing to two times per year. 

How can you apply this in your park?  Meadows can be integrated into most park sites; particularly along riparian corridors and, forest edges and within un-programmed open space.  Meadows diversify the land cover; attract butterflies, birds, and wildlife; and reduce on-going maintenance costs associated with mowing.  Trails can be created through the wildflower and/or warm season grass meadow and bluebird boxes can be put up to create wildlife viewing opportunities.  Educational signage can be installed to present the environmental and ecological benefits meadows provide vs. turf.

Runoff Capture and Reuse- encompasses a wide variety of water storage techniques designed to “capture” precipitation, hold it for a period of time, and reuse it.  These storage techniques may include cisterns, underground tanks, above-ground vertical storage tanks, rain barrels or other systems. 

How can you apply this in your park?  Rain barrels and cisterns can be used in parks to capture roof runoff from pavilions, environmental education centers or community recreation centers to then be used to irrigate gardens and water plants, flush toilets, storage for firefighting needs, etc.

You can find more information about Stormwater BMPs in the PA Department of Environmental Protection Stormwater BMP Manual here.

Promoting Green Infrastructure

Sometimes it’s hard to convince people that more trees are good or that the extra cost for installing pervious paving can go a long way later.  The good news is that the Federal, State, and local governments are starting to recognize the importance of green infrastructure in protecting our health, safety, and welfare in addition to future cost savings and improving the environment. 

For example, the Borough of Etna, Pennsylvania has had its fair share of flooding problems.  Located in the flood plain where Pine Creek enters the Allegheny River, Etna received millions of dollars of flood damage during the heavy rains of Hurricane Ivan in 2004.  Even during lesser storms, Etna is prone to flooding.  In order to help solve this problem, the Borough has recently secured a state grant plus some of its own money to install permeable sidewalks and rain gardens.  Check out this article for more information.

Permeable pavers such can help reduce flooding and the cost of flood damage.

Want to know the economic value of green infrastructure’s benefits for your community?  The Center for Neighborhood Technology (CNT) and American Rivers have released a guide that places an economic value on the numerous benefits provided by green infrastructure.  Download “The Value of Green Infrastructure: A Guide to Recognizing its Economic, Social, and Environmental Benefits” here.

What is Green Infrastructure?

When you think of infrastructure, you usually think of things like roads, sewer systems, water supply, power grids, etc…  It is the basic physical structures needed for a community to enable, sustain, or enhance a certain standard of living for its residents.   It enables the buying and selling of goods and services at a more efficient level.  Could you imagine your workplace without internet, electricity, or even roads connecting you to your clients? 

Wetlands and riparian buffers are green infrastructure.

 But what does it mean when “green” is placed in front of the word infrastructure?  Green Infrastructure is a concept that can, and should, be applied to all different scales of planning and design.  Basically, it includes everything from strategically planned and managed networks of natural lands, to working landscapes, to recreational landscapes, and other open spaces that conserve ecosystem values and functions.  In other words, greenways, parks, riparian buffers, wetlands, floodplains, rivers, and even stormwater Best Management Practices such as rain gardens, porous pavements, green roofs, and trees are all part of Green Infrastructure.  It recognizes the importance of natural systems and processes within our communities.

Green roofs and rain gardens are green infrastructure.

Why has Green Infrastructure become so important in the last 10 or 20 years?  Well, because it is beneficial for the environment, human health, the economy, and our society as a whole.  Working with and using natural processes ensures that we’ll have resources for future generations.  Stormwater BMPs reduce flooding, pollution, and the strain on our storm sewers.  Street trees beautify our neighborhoods, increase property values, reduce the urban heat island, and absorb air pollution and stormwater.  Greenways help protect steep hillsides from being developed and eroded, protect wildlife habitat, and offer recreational opportunities.  Constructed wetlands not only provide wildlife habitat but filter pollution and even human waste. 

So the next time you step outside, try to identify what types of green infrastructure are present and how they help to make your community a better place.