Lack of Riparian Cover May Affect Stream Temperature

Kevin Ashman, a researcher with Georgia Southern University, and his team recently analyzed stream water temperatures at six different golf courses in Greenville, S.C.

Ashman monitored the water temperatures of the streams at each course, specifically in locations where there are continuous, tributary-free and lake-free reaches that pass through the golf course grounds.

“We chose a continuous, tributary-free stretch of stream to make sure that our results only reflected temperature changes caused by the golf course,” explains Ashman. “We also chose a lake-free stretch of the stream to show that even without a lake, which could impact stream temperatures, there were still significant temperature increases downstream.”

As part of their monitoring strategy, Ashman and his team used HOBO® Water Temp Pro v2 temperature loggers from Massachusetts-based Onset Computer Corporation.

The loggers, roughly the size of a miniature flashlight, were secured to the bottom of the streams at each of the selected courses, and water temperature measurements were taken at five-minute intervals at sites upstream and downstream away from the course.

Data from the loggers were offloaded directly to a laptop and analyzed using HOBOware® Pro graphing and analysis software, which converted the collected data into easy-to-read graphs that reveal spikes in water temperatures.

In addition to water temperatures, the team monitored stream discharge measurements under baseflow conditions, stream length between sampling sites, the extent of riparian cover along the stream banks, and any human alterations to the stream's channel.

“The data revealed consistently higher stream water temperatures on the order of 4 – 10°F during the afternoon hours, and significantly larger diurnal temperature ranges – typically two to three times larger – compared to their upstream counterparts,” says Ashman.

According to Ashman, the temperature differences between the up and downstream sites were primarily due to the lack of riparian cover along the golf course reaches, and to a lesser extent, alterations in the stream channel’s structure.

“Although the impacts of these temperature modifications on the ecology, biology, and chemistry of the stream system are not known, the magnitude of the temperature change is large enough to be of potential consequence,” says Ashman.

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