Livable/Sustainable GI 10

Published on April 14th, 2016 |

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City unveils new Green Infrastructure Plan to manage stormwater

Atlanta recently unveiled its new Green Infrastructure Strategic Action Plan—a concept for how the city will deal with stormwater management—but the ideas posed in the plan are anything but new.

The cover for a sewer separation plan using greenways from 2002.

The cover for a sewer separation plan using greenways from 2002.

Many of the concepts were unsuccessfully offered up in the late 1990s and early 2000 by a group of environmentally motivated individuals who were opposed to the city spending a couple of billion dollars on an underground tunnel they knew would not be the solution to effective stormwater management.

Bill Eisenhauer, Jackie Echols, Bob Schreiber and, to a lesser degree, Justin Wiedeman talked of developing stormwater holding ponds as centerpieces for new parks in neighborhoods all around the city as an environmentally sound stormwater management program.

More than a dozen years later, a task force developed the Atlanta Green Infrastructure Strategic Action Plan (GI), the centerpiece of which is parks with stormwater holding ponds, like the one the city developed in the past couple of years in the Old Fourth Ward section of the city.

The city of Atlanta, like many cities, has always struggled with managing stormwater runoff that causes flooding, degraded water quality, streambank erosion, and property damage.

GI is a cost-effective approach to managing stormwater runoff that emphasizes infiltration, evapotranspiration, and reuse that also complements traditional engineered approaches in both combined and separated stormwater systems.

GI uses natural systems and/or engineered systems designed to mimic natural processes to more effectively manage urban stormwater. These systems are often soil or vegetation-based and

The actual retention pond and park at the Old Fourth Ward.

The actual retention pond and park at the Old Fourth Ward.

include planning approaches such as forest conservation and restoration, urban tree preservation and impervious cover reduction, as well as structural practices such as rain gardens and permeable pavements.

By maintaining and restoring the natural hydrologic function of urban areas, GI treats precipitation as a resource rather than waste, and can play a critical role in improving community development as well as achieving water quality goals.

GI can also revitalize urban communities by providing much-needed green space for recreation, increase the value of adjacent properties, provide wildlife habitat, and mitigate some of the heat island effect of dense urban areas.

GI works by reducing the volume of stormwater discharging through grey infrastructure (typically piped systems that discharge directly into bodies of water, or water treatment facilities) by managing rainwater where it naturally falls and removing many of the pollutants present in runoff.

In a nutshell, green infrastructure involves managing rain near where it falls, rather than at a sewer treatment plant. The water feature at Atlanta’s Old Fourth Ward is a green infrastructure project that manages stormwater on site, rather than at the Clear Creek CSO (Combined Sewer Overflow) Treatment Facility.

McDaniel Branch constructed wetlands area.

McDaniel Branch constructed wetlands area.

By reducing volume and pollutants, these systems make an effective strategy for addressing wet weather pollution and improving water quality.

“It is my goal for Atlanta to become one of the top tier sustainable cities in the nation,” Atlanta Mayor Kasim Reed states on the opening page of the green infrastructure plan. If that is to be part of his legacy, the city needs to ramp up implementation, which may not need City Council approval.

There is some disagreement among BuckheadView’s professional resources—most of which have been closely involved with the city’s sewer problems for almost 20 years—as to whether these green initiatives will have a major effect on the flooding and combined sewer overflow issues in the city—especially the Peachtree Creek basin and Memorial Park area of south Buckhead.

Water attorney Craig Pendergrast, who has been involved in discussions with the city on the Memorial Park flooding and sewage spills issue, told BuckheadView he is supportive of green infrastructure (GI) plan. It is important, he said, “to get to the stormwater and manage it before it gets into the combined sewer system and even the

Atlanta City Hall's green roof, which was first installed on municipal building in Southeast.

Atlanta City Hall’s green roof, which was first installed on municipal building in Southeast.

separated sewers.”

Pendergrast added, “It’s a need, a problem, an improvement that cuts across all neighborhoods of Atlanta.”

Elaborating on the problems of flooding and raw sewage spills into neighborhood streams, Pendergrast said, “We have beautiful bones in this city….not all creeks are paved over. Where we have creeks, they should be an environmental and recreational asset.”

Though the plan is clearly aspirational, it does set out a concrete objective: To remove 225 million gallons of runoff each year, starting with the coming year.

That objective is to be achieved by reducing the amount of runoff from each 1-inch storm by 1 percent, which equates to 6.4 millon gallons of the 640 million gallons of runoff generated by a 1-inch storm. This would enhance efforts by the private sector already has implemented to reduce stormwater runoff.

Permeable pavers roadway being installed in southeast Atlanta.

Permeable pavers roadway being installed in southeast Atlanta.

As proof of GI’s potential, the plan observes that GI was used at nearly 2,000 construction projects. The plan reports that 350 million gallons a year of stormwater have been averted since the city enacted, and developers complied with, stricter stormwater management regulations in 2013.

The plan’s No. 1 priority is to incorporate green infrastructure into the projects that are to be built with proceeds of the $252 million infrastructure bond Atlanta voters approved a year ago.

But the city needs to hurry to meet that goal. While the city presently is installing six miles of permeable paver roadways to help alleviate flooding in neighborhoods served by the City’s combined sewer infrastructure (such as the Peachtree Creek basin), portions of 15 streets have already been repaved with traditional methods, according to a city website.

As for the permeable pavers, two of BuckheadView’s professional sources pointed out that they will become clogged and then will be useless unless thy are replaced. Another said he felt the pavers were “window dressing.”

The No. 2 priority is to create a GI feasibility checklist for use by the Department of Public Works as it reviews projects.

Next in line are revising policies and procedures to support GI; devising funding mechanisms; developing public support; and tracking data and developing a pilot hydrologic and hydraulic model

Adair Park Rain Garden

Adair Park Rain Garden

in the Nancy Creek watershed.

Pendegrast understands that the program is nudged by requirements of the Department of Watershed Management’s (DWM) MS4 permits, which calls for the city to come up with written plans and is driving the Nancy Creek basin study. All of the Nancy Creek basin is on separated sewers.

To the extent the studies are driven by MS4 permits (which are permits for separated sewer systems), there may not be much activity involving the combined sewer areas of the city and the CSO system.

Pendergrast told BuckheadView that the Peachtree Creek basis now more impaired than the Nancy Creek basis is and he would have liked to have seen it studied first. But he understands the Peachtree Creek basin is next up and the results could come out sometime in the Fall.

“I would like to see the city identify specific high impact green and none-green projects in the Clear Creek and Tanyard Creek basins,” he said.

Bioretention cul-de-sac at E. Rivers Elementary School in Buckhead.

Bioretention cul-de-sac at E. Rivers Elementary School in Buckhead.

For instance, Pendergrast pointed out that the Trust for Public Land is working with the city to design Mimms Park, within the Vine City community west of the new Falcons stadium. That park will include a stormwater detention pond facility and DWM has done work on what the capacity of that detention facility should be.

Mimms Park is in the Proctor Creek basin, which is a combined sewer area of the city.

The task force that is overseeing all of this is comprised of representatives of Atlanta departments of Watershed Management; Planning and Community Development; Public Works; Parks and Recreation; Aviation; and the Mayor’s Office of Sustainability.

Partners include American Rivers; Atlanta BeltLine, Inc.; The Conservation Fund; and Invest Atlanta, the city’s development arm.

 

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    2 Responses to City unveils new Green Infrastructure Plan to manage stormwater

    1. Lisa Frank says:

      Storm water run-off can be greatly reduced if only we made it a priority to save the city’s mature trees and considered their role as part of the solution. The cost is free.

    2. I find the comments made by the professional sources concerning the clogging factor of
      Permeable Paving Systems to be somewhat confusing. Permeable Paving Systems have for decades now been used across the world predominantly in Europe, and especially Germany but also extensively in the US. Provided a comprehensive maintenance program is put in place and the system is designed and constructed correctly in the first place clogging should not be a factor. There are also machines available that can remove clean and replace the jointing material without replacing the entire pavement. Also the latest technology in permeable pavers has created a ceramic permeable paver that allows the water to infiltrate through the body of the paver rather than through the joints of the paving system. These high-tech pavers are a further step in the continuing technology that is occurring in the area of segmental paving. The pavers are extremely strong with a breaking load in excess of 10 kN and are suitable for most commercial applications including minor roadways. These types of projects that have been undertaken by many local councils throughout the world are necessary part of the future and the benefits to run-off, reduced discharge, water quality and such things as urban heat island effect are a necessary part of future sustainable planning throughout the world.

      Nicolaas Van Diemen. International Specialised Skills Institute (ISSI) Fellowship in Permeable Paving Systems. (PPS)

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