Piscataqua River Dye Study at Pease Wastewater Outfall Scheduled for July 29, 2019

Portsmouth, NH - The City of Portsmouth, New Hampshire will begin conducting a dye tracing study on Monday, July 29, 2019. The New Hampshire Department of Environmental Services (DES) will assist in the collection of data associated with the dye study. The study will continue into Tuesday, July 30, 2019. They will be tracking the flow and dispersion of water in the Piscataqua River from the City of Portsmouth‘s Pease wastewater treatment facility outfall (in the river nearest Gosling Road), upstream into the Little Bay area, New Hampshire, as well as downstream in the Piscataqua River through Portsmouth, New Hampshire, and Kittery, Maine.

Information from this study will be used by DES to determine what areas in the Upper and Lower Piscataqua River may be suitable for recreational shellfish harvest and for commercial shellfish aquaculture, while still protecting public health. Rhodamine WT dye will be released late in the evening of July 29 from the Pease wastewater outfall for a period of approximately 12 hours.  As a result of the injection, portions of the Piscataqua River may turn reddish in color for a brief time through the communities in Portsmouth, Newington, New Castle and Dover, New Hampshire and Kittery and Eliot, Maine; however, the dye is not harmful to people or the ecosystem. 

The addition of dye to the treated wastewater effluent is intended to simulate conditions that may result in the rare instance of a treatment breakdown at the facility. Measurements of dye dilution and transport in the river can then be used to identify areas that may be at a higher level of risk for contamination.  Similar studies have been conducted previously at the wastewater treatment facilities in Dover, Durham, Exeter, Newmarket, Portsmouth Peirce Island, Hampton, Seabrook, Newfields, and Kittery, Maine.

For more information, please contact Chris Nash, NHDES 603-568-6741 or Terry Desmarais, City of Portsmouth, 603-766-1421