NASA eyes Choptank watershed in Bay water quality report

Dorchester Banner/Courtesy of NASA This satellite image provided by NASA was captured by the Operational Land Imager (OLI) on Landsat 8 and was used with a NASA article written by Adam Voiland that draws attention to best management practices. Hurlock is pictured near the top right of the image. According to the article, the area east of Cambridge is part of the watershed that saw the most improvement in the University of Maryland’s report card on Bay health.

Dorchester Banner/Courtesy of NASA
This satellite image provided by NASA was captured by the Operational Land Imager (OLI) on Landsat 8 and was used with a NASA article written by Adam Voiland that draws attention to best management practices. Hurlock is pictured near the top right of the image. According to the article, the area east of Cambridge is part of the watershed that saw the most improvement in the University of Maryland’s report card on Bay health.


Editor’s note: This is the first of two stories about NASA’s report on Bay water quality. The second, which will focus more on agriculture, will appear in the Friday, Sept. 9, edition of the Banner.

CAMBRIDGE ­­— Chesapeake Bay water quality is showing signs of improvement and NASA is paying attention.
In April, The University of Maryland Center for Environmental Sciences published its annual Chesapeake Bay report card for 2015. In response, NASA used a satellite, Operational Land Imager (OLI) on Landsat 8, to capture images of areas in the Bay watershed. Those images were published online with a report by Adam Voiland, a technical writer with NASA’s Sciences and Exploration Directorate.

One image is of an area of Dorchester County that stretches roughly from Hurlock at the northeast to the Eastern Shore of the Choptank River. Cambridge is not in the frame. The image points out a chicken farm and also draws attention to some of the best management practices farmers are using to help improve Bay water quality. BMPs include planted buffer zones, artificial wetlands, manure sheds and other practices meant to catch nutrients, mainly nitrogen and phosphorus, in runoff.

The NASA article states the report “… found clearer water, lower levels of algae, and a resurgence of sea grasses. In the same month (April), the Maryland Department of Environment announced that it had mapped 53,000 acres of submerged aquatic vegetation — a record amount and a clear sign of the ecosystem’s improving health. In July 2016, the Maryland Department of Natural Resources reported that the size of the dead zone in the Bay in late June was the second smallest since 1985.”

Dr. Tom Fisher is a professor at the University of Maryland Center for Environmental Science Horn Point Laboratory. He has studied the Choptank River and its watershed for more than 20 years.

“I’m cautiously optimistic,” Dr. Fisher said. “What we’re seeing is a little improvement in water quality, but we have a long way to go yet.”

One of the tools Dr. Fisher uses to measure water quality is the Greensboro gaging station operated by the U.S. Geological Survey. The station in the upper Choptank has been collecting continuous data since 1948. The water measured there comes from a 100-square-mile watershed.

Data from the Greensboro station shows “no sign of improvement at all,” Dr. Fisher said.

There are small signs of improvement in bigger water near Cambridge and the mouth of the Choptank where Dr. Fisher monitors another measuring station. For close to 30 years, he observed degrading water quality there, but the trend changed slightly in 2015.

“The last couple years, we’ve seen a little change,” near Cambridge, Dr. Fisher said. He has also seen improvement with his own eyes. “In 2015 … we saw the bottom in places that have never been seen before.”

Dr. Fisher said much more work is needed to improve water quality in the Choptank and the Bay, but he speculates that agricultural BMPs, improved wastewater treatment facilities and septic systems may be contributing to the slight improvement. The NASA article echoes Dr. Fisher’s sentiment.

“While efforts to minimize pollution from agriculture have started to pay dividends, plenty of work remains before the Bay will get a clean bill of health,” the article states. “Indeed, despite the improvements, the 2015 report on the Bay’s health gave the water a ‘C’ grade. And for many of the most important rivers, manure and fertilizer remain the sources of half of all the nitrogen and phosphorus that drain into the Bay.”
Despite more need for BMPs and other practices to improve Bay health, it’s important to draw attention to farmers who are working to improve water quality. Dr. Fisher also works directly with farmers to both help install and measure the effects of BMPs.

“I’m glad to see that NASA is using remote sensing now to look at how land use affects water quality and that they’re looking at agricultural best management practices,” he said. “It’s good for the farming community to hear that their efforts are being acknowledged. … We need more of what they’ve been doing.”

To read the NASA report, “How Farms Affect the Chesapeake Bay’s Water: Image of the Day” visit http://earthobservatory.nasa.gov/IOTD/view.php?id=88523

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