Susquehanna Flats bay grass beds survive late summer hurricanes, rain storms

Though the final figures on the overall health of the Bay’s underwater grasses won’t be available for a few months, in late November, scientists with the Chesapeake Bay Program’s (CBP’s) team that monitors the abundance of the Bay’s grasses had a pleasant surprise. Aerial survey images of the vast grass-filled Susquehanna Flats, the circular area where the Susquehanna River meets the Bay, were not pictures of devastation as was feared, but pictures of health, showing that these valuable Bay habitats survived the fall’s deluge of runoff and sediment better than expected.

During Hurricane Irene and Tropical Storm Lee, experts out monitoring the effects of these storms noted large tangles of all varieties of uprooted Bay grasses floating downstream. Based on these visual accounts and their knowledge of the devastation that events such as Tropical Storm Agnes wrought on the Bay’s grass beds almost forty years ago, hopes among scientists were not high for these habitats, which are a critical food source for over-wintering waterfowl at this time of year and that are vital as shelter for juvenile Bay creatures in the spring.

“We were incredibly surprised at how much of the grass bed remained on the Flats,” says Robert Orth of Virginia Institute of Marine Sciences (VIMS) and leader of the team that conducts the annual survey of Bay grasses. “While we did see some declines along the flanks and edges of that big bed, my gut feeling says next year should be ok for grass beds up there. And the fact that we are now seeing overwintering waterfowl in our photographs is a good sign that lots of food is available.”

CBP’s Associate Director for Science Rich Batiuk commented, “Back on those days of Tropical Storm Lee, looking at the deluge of water over the Conowingo Dam, I would’ve bet that we had lost the Flats grasses entirely. Their survival is a good example of how large, dense beds can survive extreme conditions and another indicator of the Bay’s resilience.”

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Compare the underwater grass beds on the Susquehanna Flats in VIMS aerial photographs in 2010 and 2011 at http://thumper-web.vims.edu/bio/sav/wordpress/archives/1458