URI oceanographers receive grant to track water from treatment facilities into Narragansett Bay and the Providence River
Narragansett, RI -- January 27, 2005 -- University of Rhode Island oceanographers Dr. Chris Kincaid and Dr. Deanna Bergondo have received a two-year, $157,000 grant from the Narragansett Bay Commission (NBC) to develop a computer model for tracking and predicting the dispersion of water from the NBC water treatment facilities within the Providence River and Narragansett Bay.
Kincaid and Bergondo will develop computer models of circulation and transport within the Providence River and upper Narragansett Bay to aid in the management of the NBC treatment facilities. The models are based on measurements from buoys equipped with sensors as well as from field surveys conducted during each seasonal period.
The model domain developed by Kincaid’s group will include the Providence River, Mount Hope Bay, the Sakonnet River, and Rhode Island Sound. The mouth of the Seekonk River will be the northern boundary of the Providence River, allowing the scientists to input conditions created by waters flowing from the Seekonk River into the Providence River.
“Episodes of low oxygen are of growing concern for the upper parts of Narragansett Bay, the Providence River, and Greenwich Bay,” said Kincaid. “A big question in the oxygen balance is how effectively water is flushed from the system. This modeling builds upon a previous Narragansett Bay Commission funded effort which provided the most detailed spatial images on circulation ever collected within upper Narragansett Bay."
These data reveal rivers within the Providence River. In a general sense, water moves towards the ocean in a shallow current that hugs the western side of the shipping channel. A deep northerly current carries water from Ohio Ledge back towards Providence, occupying the bottom of the shipping channel and often extending to the surface along the eastern side of the river.
"We have also identified a number of areas where water movement is much more sluggish, often in an opposite direction from what is expected for the stage of the tide. If you have ever played a child’s game where sticks are dropped in a river to see whose makes it downstream fastest, you probably know these types of stagnation regions. They are where your stick or leaf gets hung up and simply moves in circles."
The modeling also builds upon the significant data sets from moorings developed and maintained by the late Professor Dana Kester and Bergondo, his PhD student.
The modeling is a way of extending the physical and chemical data in both space and time and provides a tool for testing ideas for how the Bay works. For example, a goal of the work is to predict how releases from the NBC treatment facility are transported or flushed through this system under these flow conditions versus when environmental conditions change things. As a check for the model, additional measurements will be made using moored current meters to document how circulation changes in the stagnation regions versus the channel with wind and rainfall events.
An additional goal of the modeling project is to document how NBC releases move outside of the Providence River, specifically in terms of their potential for impacting Greenwich Bay. Current meter measurements will be made around Prudence Island and across the mouth of Greenwich Bay to verify circulation trends and transport pathways predicted by the models. These data will be used in developing and checking models for how much of NBC effluent passes through the East verses West Passage of the Bay and under what conditions the effluent enters Greenwich Bay.
Preliminary model results show that moderate to low runoff and winds from the north or east carry Providence River waters to the mouth of Greenwich Bay. Higher runoff and winds from the west or south tend to confine Providence River outflows to the eastern side of Prudence Island.