SYRACUSE U. (US)—More than one-third of the 90-kilometer length of Central New York’s Three Rivers system failed to meet the state’s water quality oxygen standard in a recent study.

Oxygen levels in the Oswego, Oneida, and Seneca rivers were found to be degraded by several stressors, including the impact of wastewater treatment plants, nonpoint runoff, an increase in invasive zebra mussels, and channelization of the flow.

“This study illustrates some of the complexities and challenges in managing urban water systems,” says Charles Driscoll, professor of environmental systems engineering at Syracuse University.

“There are multiple factors associated with the low oxygen concentrations in the Three Rivers system. As a result, multiple approaches will be needed to improve the oxygen status of the river.”

While much attention has been given to the impact of rivers on lake water quality, there had previously been little done to track the effects of lake outflows on receiving rivers.

The water quality of these rivers is of great concern in order to protect their multiple uses—recreation, navigation, power generation, and waste discharge—and to support regional development. Currently, the ability of the water systems to absorb the waste sent into them is significantly reduced.

To assess the water quality of such large river systems, the study conducted eight longitudinal surveys—four in summer 2007 and four in summer 2009—collecting data from more than 50 sites, utilizing special instrumentation that measures temperature, conductance (the capacity to conduct electricity), turbidity (muddiness of water due to stirred up sediment), chlorophyll levels and dissolved oxygen.

The “boundary conditions” that show the baseline measurements were collected by solar-powered robotic monitoring platforms at the outflows of each lake.

With much conclusive evidence pointing to the oxygen depletion in the Three Rivers system, the research team recommends long-term, routine monitoring of the system, utilizing robotic systems.

Simply improving processes at individual wastewater treatment plants will not be enough to impact the system, and the team must continue to define dynamics and provide insights for rehabilitation. A water quality model can then guide management decisions for a recovery process.

More Syracuse University news: