Metro Green Infrastructure Master Plan Now On-line

1 09 2010

Metropolitan Nashville-Davidson County’s Green Infrastructure Master Plan is now available on Metro Water Services’ website. The plan was prepared by amec, Hawkins Partners, Urban Blueprint, and the Low Impact Development Center. The plan includes the following:

  • Green Infrastructure Practice – Overview of Green Infrastructure and descriptions of various practices.
  • Technical Analysis of Green Infrastructure – Analysis of the CSS area with respect to green roofs, three kinds of infiltration practices, tree planting, and rainfall harvesting (cisterns and rain barrels) and its potential impacts on the CSS.
  • Green Infrastructure Projects – Brief overview of the preliminary design concepts for six projects.
  • Green Infrastructure Incentives and Financing – Summary of various potentially applicable incentive practices that have been applied in other cities to encourage the use of Green Infrastructure.

Click here to download the entire plan in PDF format





Eco-roofs in Portland: Creating Habitat [VIDEO]

2 04 2010

Screenshot of KGW News Story

I came across this news segment from KGW News in Portland regarding the City’s eco-roof initiative and the recent visit by Dusty Gedge, president of the European Federation of Green-roof Associations. In addition to many of the other benefits of green roofs, the city is also promoting the creation of eco-roofs to establish habitat for dry riverbed species in particularly the diverse species of birds that migrate through the city. I couldn’t embed the video but here is a link to it and the transcript.  Tom Liptan, an Environmental Specialist with Portland’s Bureau of Environmental Services, summed it up well by saying.

“The benefit of an eco-roof is that it provides habitat for various species that are losing that kind of habitat in most urban environments around the world.”

-Brian Phelps






Ecological Importance of Southeastern Rivers

10 03 2010

Interpretive signs for an upcoming project near the Harpeth River in Williamson County will highlight the ecological significance of the waters of the southeastern United States. If you didn’t know, the rivers and streams of middle Tennessee are part of the most unique and diverse freshwater ecosystem in the entire world. This has to do with a couple things, namely the temperate climate combined with the fact that much of the area was unglaciated, or it as been more geologically stable than other parts of the U.S.

Just to give you an idea the area is home to more than 250 species of crayfish (70% of all the species in the entire U.S.), more than 300 species of mussels (over 1/3 of these live in Tennessee), and more than half the freshwater fish species in the U.S. Because of this great diversity, Tennessee has more freshwater fish that are at-risk than any other state. These species are at-risk largely due to pressures from development practices, which allow sediments and pollutants to wash into our rivers and streams. This and other topics concerning protection of critical watersheds can be found in, Rivers of Life or States of the Union: Ranking America’s Biodiversity, just some of the publications found on the NatureServe’s website.

Graphic from 'Rivers of Life', published by NatureServe

As mentioned in an earlier post, the implementation of ‘green street’ practices on Deaderick Street in downtown Nashville will divert approximately 1.2 million gallons of stormwater a year from the Cumberland River. This is water that would have otherwise run unabated into the river carrying all of the pollutants and sediments from the street. Understanding the significance of the region’s biodiversity is a good reminder of what we are trying to protect when implementing green infrastructure planning and strategies –and why this is especially important here in the Southeast and Middle Tennessee.

-Sara Putney





Invasive Species in the News

15 01 2010

When we plan and design for projects, within our trade, we try to use native species whenever possible. This is especially important when designing green infrastructure projects that tie so closely to our natural resources, in particular our waterways. Oftentimes people wonder why this is so important and how can it really affect them anyway? Whether it’s plant materials or animals, all invasive species are eventually extremely damaging to our native ecosystems. And also extremely costly; “The UN Convention on Biological Diversity says the spread of invasives costs 1.4 trillion dollars a year globally in damages and control measures. The U.S. alone loses 138 billion dollars a year in the fight.”

Image from ‘The Dirt’ website.

In ASLA’s blog ‘The Dirt’, a recent posts highlights the efforts for the State of Michigan to protect Lake Michigan and the entire Great Lakes Region from the Asian Carp. Like all invasive species these fish take over an ecosystem by consuming resources that would otherwise be used by the native species. Michigan is suing the State of Illinois in order that they shut down the waterways leading into Lake Michigan. According to the New York Times article Minnesota, Ohio, Wisconsin, and Indiana are all in support. This came to light due to recent evidence of the carp within 6 miles of Lake Michigan in the Chicago area waterway system that links the Mississippi River to the Great Lakes. And while the City of Chicago realizes that the carp overtaking Lake Michigan would be devastating they are wrestling with their own economic concerns over what closing the waterways would really mean. There is more detailed information in ‘The Dirt’ post and the New York Times Article.

Another item in the light recently is the efforts of the Chicago Botanic Garden and the Morton Arboretum to gather native seeds from around the Midwest. “Scientists from the botanic garden are sending teams out across the Midwest and West to the Rocky Mountains and Great Basin to collect seeds from different populations of 1,500 prairie species by 2010, and from 3,000 species by 2020. The goal is to preserve the species and, depending on changes in climate, perhaps even help species that generally grow near one another to migrate to a new range.” The idea is to catalogue, store and preserve native plants in the event that climate change or invasive species may require the migration of native plant materials to other areas. There is still much debate about the project and more detailed information can be found in the New York Times article.

These are just two examples in a long list of invasive species problems that continue to threaten the ecosystems of the US. Not only do invasives disrupt plants, animals and other natural resources, but as noted above they also can have huge negative economic impacts. This coming on the tails of National Invasive Species Awareness Week, (January 10-14th), to learn more visit the National Invasive Species Information Center’s website.

– Sara Putney





Getting More: Multi-Functioning Facilities

13 01 2010

When it comes to adding more park space, communities are increasingly looking at getting more bang for their buck. Budgets are tight and cities are having to pool their resources from a variety of sources to get projects built. Two recent projects, one that is under construction in Los Angeles and another just announced in New York City, seek to create a park and nature area for their citizens while also constructing wetlands to address stormwater management issues within the immediate neighborhood and the community at-large.

The first is the South Los Angeles Wetland Park. The 9-acre park under construction five miles south of downtown Los Angeles on a former transit maintenance facility that is nearly 100% paved. The City recognized that more recreational open space was needed in the area while also needing to improve the quality of the stormwater runoff that ultimately was polluting the city’s beaches. The park transforms the site into a extensive wetland that comprises most of the park. It includes a series of trails, an observation area, and public gathering areas.

The park is estimated to cost $24 million. The funding was cobbled together from a variety of sources, including money generated from Proposition O. Proposition O passes in 2004, authorized the city to issue up to $500 million in bonds for cleaning up polluted storm water and bacteria in the City’s rivers, lakes, beaches and ocean. Stormwater Magazine has a thorough article about the genesis of the park and its design. Also, more detailed information can be found on Proposition O’s website.

South Los Angeles Wetland Park Site Prior to Construction
Source: Google Map

South Los Angeles Wetland Park Site Plan
Source: Proposition O Website

The second improvement is the Paerdegat Basin Restoration Project in New York City. The Department of Environmental Protection recently announced the $15 million project. It is anticipated to be completed by 2012. The park will restore 38 acres of wetlands and natural grassland areas adjacent to the $357 million Paerdegat Basin Combined Sewer Overflow (CSO) abatement project. Five acres will be dedicated as a Ecology Park that will be accessible by the public and offer educational opportunities. Funding for the project is provided by Clean Water State Revolving Funds. The combined projects are designed to store 50 million gallons of CSO during a storm event. (Press Release fro DEP)

Both of these projects serve as examples of how various communities’ goals can be combined and met by a single green infrastructure investment. As cities approach future planning and implementation efforts, they should look beyond the immediate objectives of the project and assess how the project might serve to address other needs that have been identified in the community.

-Brian Phelps





The Green Vs. Standard Showdown

11 01 2010

We do a lot of talking about green and trying to convince clients to do it. And then we wait for the question that will eventually come…….. so what’s the premium that I have to pay for that?

Not too long ago we had a client that took a big step. They commissioned us to have full schematic plans developed for their hospital site in North Carolina with both alternatives: green and conventional. The parameters, such as site area and number of parking spaces required, were the same. The conventional design used curb and gutter, catch basins, and underground piping to carry the water to detention ponds and/or the storm sewer system. The “green” alternative used planted bioswales throughout the parking lot, curb stops at some parking spaces to allow for surface drainage into bioswales and a water collection system to divert the roof water into a channeled weir as an amenity which leads to the on-site pond. The general contractor priced both alternatives while we held our breath………… the green alternative checked in right at 3% less than the conventional plan for the overall site improvements.

Johnston Memorial "green" site plan

You might say that a 3% cost savings is not significant, but the green plan has the added advantage of making the site more aesthetically beautiful while meeting the stormwater needs. The conventional plan priced ordinance-required landscape only while the “green” plan provided considerably more landscaping (5x the ordinance plan) to densely plant the bioswales for water quality purposes while reducing sod and irrigation. The additional benefits of this solution, beyond water quality and allowing for infiltration and recharge of the insitu soils, were providing wildlife habitat, reduction of life cycle costs through reduced maintenance and water cost for irrigation and a “free” water feature through the roof collection system diverted through a structured weir. Studies done by Texas A&M also show that views of landscape and natural systems also benefit the healing process, not to mention the mental health of the staff and visitors to the facility. An intangible that was also a factor was the speed with which the green alternative made it through the planning process and permitting.

At Johnston Memorial Hospital in Clayton, NC, the total site area was approximately 75 acres. For the” green” plan, over 39,100 sf of the parking lot was designed as bioswales giving an impervious to pervious ratio of 4.5:1 (176,000 sf: 39,100 sf). The bioswales were planted with almost entirely native plant material, which are well adapted for this situation. Plants like clethra, wax myrtle and itea formed a basis for the woody shrubs and native grasses and reeds like panicum, river oats and juncus added to the mix. Native perennials like aster, black-eyed susan and joe-pye weed add seasonal color without the replanting and maintenance cost of annuals.

We appreciated having a client go through this exercise of comparison, and we love being able to provide a client with a solution that saves them money and is more sustainable for the environment at the same time.

-Kim Hawkins





Getting the Facts: Monitoring Green Infrastructure

8 01 2010

In Wednesday’s post, I mentioned the benefits of monitoring to help explain the reasons why green infrastructure facilities are being employed in their neighborhoods and specifically their effectiveness in improving water quality in our rivers and stream for which we all depend.

The City of Portland has done a great job at monitoring their green streets and other green infrastructure facilities. They provide this information on the Bureau of Environmental Services’ (BES) website. Their 2008 evaluation of their green street facilities have shown that for a 25-year storm event ( 25-yr, 6-hr) that peak flows were reduced by 80% or more. For CSO compliance events, their studies were shown to capture 60% or more of the storm volume.

It appears less has been published by the City on the pollutant removal capabilities for green streets. However, as mentioned in the article, studies conducted across the country have shown bioretention areas, the main stormwater management component of a green street, have been shown to be very effective. EPA’s fact sheet on bioretention shows the following removal rates:

  • Total Phosphorous: 70%-83%
  • Metals (Copper, Zinc, Lead): 93%-98%
  • Total Kjehldahl Nitrogen (TKN): 68%-80%
  • Total Suspended Solids: 90%
  • Organics: 90%
  • Bacteria: 90%

These number continue to be supported through researched conducted over the last decade. The concern that the accumulation of these pollutants, particularly metals will pose health risk have been unsubstantiated. A four-year study by Philip Jones (student) and Dr. Allan Davis (advisor) at the University of Maryland, showed the level of pollutants that accumulated within a bioretention cell on campus to exceed soil background levels but were far below EPA cleanup standards.

It is important to remember that currently, most conventional stormwater devices have no capacity to address pollutant removal. Portland is at the forefront in implementing green infrastructure practices and will be well positioned as Federal standards continue to be strengthened over the coming decade. More importantly, they are improving the water quality of their rivers for future citizens.

If fact, the EPA recently announced they are conducting stakeholder input in an effort to initiate a national rulemaking that would establish a comprehensive program to reduce stormwater discharges from new development and redevelopment and make other regulatory improvements to strengthen its stormwater program. At a minimum the EPA intends to propose a rule to control stormwater from newly developed and redeveloped sites, and to take final action no later than November 2012.

-Brian Phelps