Will all the rain this spring have an
The short answer is yes. The Chesapeake Bay watershed has experienced greater-than-average rainfall amounts over the past few months. The National Weather Service reports May 2009 as the second wettest on record with a total of 8.42 inches; and June is closely approaching its average rainfall in just the first two weeks of the month.
All of this rain has to go somewhere, and with the ground already full of water, much of the rain flows across land as surface runoff, entering into creeks, streams and eventually the Chesapeake Bay. The runoff carries with it nutrients and sediments. These nutrients can fuel the rapid growth of algae in the Bay. When the algae die, decomposition of the algae can rob the Bay’s waters of oxygen. In late May, we observed massive growth of the algae Prorocentrum minimum in areas of the Bay, partly due to the effects of the excessive rainfall. Die-off of the algae in the Baltimore Harbor resulted in a significant number of dead fish.
Additionally, the sediments carried in rainfall runoff can reduce water clarity, which makes it harder for the sun to reach the Bay bottom. This “shading” effect may impact the early growth of bay grasses, reducing the area of important habitat for many Bay animals.
The Maryland Department of Natural Resources will continue to monitor the impacts of this year’s rain on water quality and habitat. Current monitoring data can be viewed at http://www.eyesonthebay.net.
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