A high-tech buoy that monitors water quality in real time was just installed in one of New England’s most popular lakes, where in the future it will help with determining when swimmers should and shouldn’t be in the water. Scientists from the U.S. Geological Survey (USGS), with support from NH Departments of Environmental Services (NHDES) and Health and Human Services (NHDHHS), deployed the buoy and weather station at Weirs Beach on Lake Winnipesaukee at the beginning of June. The buoy will provide real-time temperature, specific conductance, pH, dissolved oxygen and water levels, all clues to that may help predict when bacteria levels are too high to permit swimming.
“The USGS will be comparing the buoy measurements with culture-based E. coli samples to better understand what environmental conditions may lead to high bacteria counts at Weirs Beach,” says Richard Kiah, a supervisory hydrologic technician from the USGS New England Water Science Center and project lead. “Once we understand the correlation, we will be able to develop a model that will help state officials make real-time decisions on when water conditions are not suitable for swimming.”
It is unclear exactly what environmental conditions lead to high bacteria counts, but several factors are possible. These include high water temperatures, the presence of aquatic birds, high swimmer counts, failed septic systems and storm water runoff. Once the concentration of E. coli in lakes reaches a certain level, state officials issue swimming advisories recommending people stay out of the water.
“Bacteria counts resulting in no-swimming advisories can occur frequently and often when and where people most want to go swimming,” says Sonya Carlson, beach program coordinator from NHDES. “At Weirs Beach, the most popular and well-known beach on Lake Winnipesaukee, ‘no swimming advisories’ were posted after 29 percent of all samples taken from 2003-2014.”
Currently, the State of NH evaluates swimming conditions at more than 160 inland beaches statewide using culture-based methods for determining counts of E. coli. Water samples are generally collected once a month and can take at least 24 hours to process. This time delay may result in beachgoers being exposed to high levels of bacteria, or swimming advisories being in effect for conditions that no longer exist.
The goal of this collaborative project is to produce web-based tools specific to NH beaches to help state and local officials determine when bacterial conditions may be unsafe for swimming using beach-specific data collected in real-time. A similar effort is currently underway at Pawtuckaway State Park beach on Pawtuckaway Lake. “This project is a great example of how high-quality data can be used to inform decision making at the state and local level. The real-time modeling approach has the potential to reduce human exposure to waterborne pathogens,” says Kathleen Bush, NHDHHS environmental public health tracking program manager.
The status of conditions at NH beaches can be found at NHDES Beach Maps website.
Access current water-quality conditions across the country by visiting the USGS WaterQualityWatch website. Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert.
Current Issue - April 2024