September 2006
guest feature and student guest article

ENVISIONING A “GREENROOF” POLICY FOR THE DISTRICT OF COLUMBIA - Implementing Strategies to Encourage Alternative Stormwater Best Management Practices
 

Image Courtesy of Building Logics (read about this project in The Greenroof Projects Database here).

By Gregory C. Long, R.L.A.
All photos used with permission from Greg Long

Publisher's Note:  This paper was prepared for a Virginia Tech public policy class on 12.8.05.  Greg's thesis is similar in content but he continues to collect more data and expects to have that paper finalized in the spring of 2007.  A follow-up PowerPoint version was presented to the National Building Museum as part of a symposium designed to raise awareness about vegetated roof design in January, 2006.

Abstract -
Recognizing a need to improve the quality of our local watersheds
TAKING MEASURES TO ENSURE SUSTAINABLE DEVELOPMENT PRACTICES

The District of Columbia is home to 572,000 residents¹ and covers approximately 61.4 square miles of land and like many older cities, collects much of its sanitary sewer effluent and storm water runoff in a combined sewer system.  Approximately 1/3 of the District’s land (12,478 acres)² is served by these combined sewer systems (see figure 1).  It wasn’t until the early 1900’s that city planners decided to split the two systems but by then it proved too costly to replace the existing and aging infrastructure.
 

Figure 1-Combined Sewer Systems, Watersheds, & CSO outfalls

These combined sewers generally function properly during dry weather, however, during rain events the capacity of these systems are often exceeded.  During major “wet weather" events these combined sewer overflows (CSO’s) discharge millions of gallons of untreated pollutants and raw sewage directly into the Potomac, Anacostia, and Rock Creek watersheds, causing unsafe and unhealthy living conditions for us and the environment.  In the District, there are 60 such CSO outfalls which need to be re-designed in order to meet the Environmental Protection Agency’s (EPA) Clean Water Act (CWA)³ of 1972.

The District of Columbia’s Water and Sewer Authority (WASA) has been working to bring the Combined Sewer System back into compliance with the CWA and in doing so has to prepared a Long Term Control Plan (LTCP) to manage its CSO’s.

WASA’s LTCP promises to invest over $1.2 billion to get this problem under control and to meet current development conditions and also provide for another 14 million square feet of additional building footprints over the next 20 years.  The funding for the LTCP is pledged to go directly into infrastructure improvements which will satisfy the EPA requirements.

In order to protect our water resources the District of Columbia needs to take a more holistic and comprehensive approach and implement some alternative methods and strategies towards managing D.C.’s watersheds.  This report outlines several regional and local policies that could be initiated by both the District of Columbia and WASA to ensure that the quality of our water is protected without placing an unreasonable economic burden on taxpayers.  This report will also address ways to implement, administer, and enforce these policies.  Some of the regional policies and local ordinances and mitigation measures which I will cover include:

• Implementing a watershed based zoning overlay district
• Creating a storm water management utility fee
• Providing a tax credit and other financial incentives for developers and homeowners
• Developing performance based codes and a land use development matrix
• Using LEED and green building and LID practices to manage rooftop runoff

The paper will conclude that instituting a “greenroof” policy is an inexpensive low impact development technique and a system wide control alternative that could have a significant impact on our watershed quality over the next 20 years.  This section will lend additional credibility to these theories by providing calculations based on storm water modeling depicting various development scenarios.⁴
 

Source: Casey Tree Foundation

....  To continue reading and learn more about Greg's recommendations for a Long Term Control Plan and Greenroof Policy for the District of Columbia, download the complete report in his 22-page PDF...
 

Figure 2: Combined Sewer Over flow Long Term Control Plan

Gregory C. Long is currently a Master's degree candidate of Urban and Regional Planning at Virginia Tech (MURP program) and will likely be finishing up his studies next spring (2001-present) and holds a BSLA from Pennsylvania State University, 1996.  In addition to continuing his education, Greg is a Project Manager in Bowman Consulting’s Alexandria office.  He has been with the firm since August 2003 as a registered landscape architect to help complement the land planning department.

Greg has been actively involved in issues pertaining to regional stormwater management policy/planning issues in and around the Washington D.C. metropolitan area. He has been assigned to a task force/advisory group to assist the District of Columbia’s newly formed Department of Environment on developing a newly proposed green building ordinance. This legislation and incentive based program would recommend the use of greenroofs and other low impact development (LID) practices to manage on site runoff for new construction and existing buildings. He has recently been asked to prepare workshops and lectures on the subject of greenroof and LID design for various trade organizations. In 2005, Mr. Long teamed up with Building Logics and a local non-profit “Lands and Waters” to win an award of excellence for the renovation of Yorktowne Condominiums in Falls Church, VA.

Contact Greg at:  Gregory Long, R.L.A., Bowman Consulting Group, Phone: 703.548.2188; Fax: 703.683.5781 or glong@bowmanconsulting.com.
 

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