Connecticut’s Nitrogen Credit Exchange – An Incentive-based Water Quality Trading Program

The Connecticut Department of Environmental Protection (CTDEP) has been actively involved in the operation of Connecticut’s Nitrogen Credit Exchange (NCE) since 2002. During the 2002-2009 period the total value of credits bought and sold was $45.9 million, representing 15.5 million nitrogen credits exchanged. It is one of the few expansive water quality credit trading programs successfully implemented in the United States. The program has provided an alternative compliance mechanism for publicly owned treatment works (POTW) to meet the nitrogen wasteload allocation (WLA) for the Total Maximum Daily Load (TMDL) adopted for Long Island Sound. 

View the Connecticut Department of Environmental Protection 2010 summary here: CT Water Quality Trading Summary 2010.pdf


Florida has had post-development stormwater treatment requirements in place since the early 1980’s. During the development of those rules, the performance standard was set at 80% average annual load reduction of TSS, and, based of field data, best management practice design criteria were established that provide a rebuttable presumption of compliance that stormwater discharges met the requirements. Since that time, additional research (see Harper and Baker, 2007) has shown that standard BMPs do not reduce nutrients by 80% as presumed. This draft rule was prepared by the Florida Department of Environmental Protection and the five water management districts, with the assistance of an industry working group, to provide design criteria for meeting the 80% reduction target for nutrients. The standards include the application of BMP treatment trains and advanced treatment technologies. Click on the link below to download a full copy of the draft report.


Urban Stormwater Management in the United States (NRC, 2008)

Stormwater runoff from the built environment remains one of the great challenges of modern water pollution control, as this source of contamination is a principal contributor to water quality impairment of waterbodies nationwide. In addition to entrainment of chemical and microbial contaminants as stormwater runs over roads, rooftops, and compacted land, stormwater discharge poses a physical hazard to aquatic habitats and stream function, owing to the increase in water velocity and volume that inevitably result on a watershed scale as many individually managed sources are combined. Given the shift of the world’s population to urban settings, and that this trend is expected to be accompanied by continued wholesale landscape alteration to accommodate population increases, the magnitude of the stormwater problem is only expected to grow. 

Evaluation of Current Stormwater Design Criteria within the State of Florida (Harper & Baker, 2007)

This report provides a discussion of work efforts performed by Environmental Research & Design, Inc. (ERD) for the Florida Department of Environmental Protection (FDEP) as part of Agreement SO108, titled “Evaluation of Current Stormwater Design Criteria within the State of Florida”. The primary objective of this project is to evaluate current stormwater design criteria within the State of Florida and determine if these criteria meet the treatment requirements specified in Chapter 62-40 FAC. If elements of existing stormwater design criteria fail to meet the requirements of Chapter 62-40 Florida Administrative Code.

Water Quality Credit Trading A Report to the Governor and Legislature December 2006

An excerpt from the report:

“The Florida Legislature, through the Watershed Restoration Act (Section 403.067, Florida Statutes), directed the Florida Department of Environmental Protection (DEP) to provide a report with recommendations on water quality credit trading (referred to as “pollutant trading” in the law). The DEP consulted extensively with a Pollutant Trading Policy Advisory Committee (PTPAC) comprising expertise from regulated interests, environmental organizations, water management districts, and local governments. 

Water quality credit trading is a voluntary, market-based approach to promote protection and restoration of Florida’s rivers, lakes, streams and estuaries and would supplement and enhance the other voluntary, regulatory and financial assistance programs already in place. Trading is based on the fact that businesses and industries, wastewater treatment facilities, urban stormwater systems, and agricultural sites that discharge the same pollutants to a waterbody (basin, watershed or other defined area) may face substantially different costs to control those pollutants. Trading allows pollutant reduction activities to be environmentally valued in the form of “credits” that can then be traded on a local “market” to promote cost-effective water quality improvements. 

The full text of the report can be found here: Water Quality Credit Trading Final Report – December 2006.pdf

Water Quality Trading and Offset Initiatives in the U.S.: A Comprehensive Survey

This document summarizes water quality trading and offset initiatives in the United States as of 2004, including state-wide policies and recent proposals. The following format was used to present information on each program. We attempted to have each program summary reviewed by at least one contact person for program accuracy. In the cases where this review occurred, we added the statement “Reviewed by…..” at the end of the case summary. 

Access the entire study here: Dartmouth Comprehensive Trading Survey.pdf

Urban Hydrology for Small Watersheds – TR-55

Technical Release 55 (TR-55) presents simplified procedures to calculate storm runoff volume, peak rate of discharge, hydrographs, and storage volumes required for floodwater reservoirs. These procedures are applicable in small watersheds, especially urbanizing watersheds, in the United States. First issued by the Soil Conservation Service (SCS) in January 1975, TR-55 incorporates current SCS procedures. This revision includes results of recent research and other changes based on experience with use of the original edition.

Click on the link below to open the document in a new window:

Urban Hydrology for Small Watersheds – TR-55, January 1999