Case Study

Economic Development

DC Water: Nation’s First Environmental Impact Bond and Green Infrastructure Certification


National Green Infrastructure Certification Program

DC Water was approved to use green infrastructure as a means of meeting a federal mandate of reducing combined sewer overflows by 96%. In the process, they are creating a new local workforce and innovative funding mechanism.

Washington, DC

Winters are usually chilly with light snow, and summers are hot and humid, indicating a humid subtropical climate. Annual snowfall averages 15.5 inches (39 cm).


48.3% Black or African American, 44.1% White (36.1% non-Hispanic White), 4.2% Asian, 0.6% American Indian or Alaska Native, and 0.2% Native Hawaiian or Other Pacific Islander. 2.7% from two or more races. Hispanics of any race made up 10.6% of the District's population.

The District of Columbia has one of the country’s oldest sewage systems. During moderate rain it sends untreated waste and pollution-laden run-off overflowing into the Potomac River, Anacostia River and Rock Creek. Up to three billion gallons of run-off and sewage flow into the Chesapeake Bay estuary each year, affecting industries and aquatic life alike.

Modified Consent Decree

Because of this threat, the nation’s capital is among more than 700 U.S. cities that are required by Federal regulation to invest in new infrastructure to manage stormwater runoff. In 2016, the District of Columbia Water and Sewer Authority (DC Water) executed a modification to their 2005 Long Term Control Plan (LTCP) Consent Decree to include innovative green infrastructure (GI) practices as a means of helping reduce combined sewer overflow volume by 96 percent system-wide.

They requested the shift because of all the additional community benefits GI provides that underground infrastructure does not.

Elimination of Tunnel

With this modification, DC Water eliminated a previously-planned underground tunnel for Rock Creek and is instead building GI and targeted sewer separation to manage the volume of runoff produced by 1.2″ of rain falling on 365 impervious acres of land that currently does not absorb stormwater.DC Water Green Infrastructure

Skilled Workforce

This portion of work will be completed by 2030 and will require a skilled workforce that does not yet exist to do technical jobs that cannot be outsourced. To that end, DC Water partnered with the Water Environment Federation to establish an ambitious local jobs program that includes training and certification opportunities for District residents interested in GI construction, inspection and maintenance jobs. The certification, however, has been designed for national application. The training was initially piloted in 2016, with certification testing in summer and fall of 2017 and a national rollout in 2018.NGITP

What is Green Infrastructure?

GI is an approach to managing stormwater runoff that takes advantage of natural processes such as infiltration and evapotranspiration, to slow down, clean and in some cases reuse stormwater to keep it from overwhelming sewer systems and polluting waterways.  The goal of GI is to mimic the natural environment through the use of plants, trees and other measures. Types of GI include:

  • Roof Top Collection Practices: rain barrels, cisterns, green roofs, blue roofs
  • Permeable Pavements: porous asphalt, pervious concrete, permeable pavers
  • Bioretention: tree boxes, rain gardens, vegetated filter strips, bioswales

  • DC Water is spending more than $100 million on green infrastructure
  • An innovative environmental impact bond (EIB) was issued to cover some of those costs and minimize risks.
  • It links financial payouts to environmental performance.
  • $25 million sold privately to Goldman Sachs and the Calvert Foundation.
  • Green infrastructure is less predictable and measurable than grey infrastructure
  • The EIB effectively insures DC Water against extreme underperformance.
  • If the green infrastructure reduces runoff as expected in 95 out of 100 iterations, the EIB will function like a conventional 30-year municipal bond.
  • Investors will receive the stated 3.43-percent coupon rate and the principal at maturity.
  • See Conservation Finance Network for more information
  • Trainings are held through partnering organizations. The course has a minimum of 35 total contact hours, which include at least seven hours of field or interactive educational activities.
  • Candidates seeking the GI certification must meet the following eligibility requirements:
    • Complete a GI training course that meets the requirements (as listed in Section 1 of the Applicant Handbook) or is approved by the Water Environment Federation;
    • Hold a high school diploma or the equivalent;
    • Take and pass the GI examination; and
    • Attest to the NGICP Code of Conduct.
  • DC Water
  • Water Environment Federation
  • US Environmental Protection Agency
  • US Department of Justice
  • District of Columbia
  • Various water management agencies in cities nationwide
Lessons Learned

It is always valuable when entities that could solve their problems by other means become the lead advocate for trees and other green infrastructure as their solution of choice. According to DC Water, the benefits are:

  • Sooner: GI provides water quality benefits as soon as installation begins.
  • Better: GI offers environmental, social, and economic benefits that would not be realized under the previous plan.
  • Stronger: The revised schedule allows for an additional five years to complete the tunneling project. This additional time will help protect ratepayers responsible for financing the $2.6 billion project.
  • Jobs: DC Water established a goal to have 51% of new jobs created by the GI project filled by District residents.
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