Even in clear weather, the Hudson River is a significant source of sediment to New York Harbor, where millions of dollars are spent annually maintaining navigation channels and disposing of dredged sediment. After drenching rains fell from Hurricane Irene, the Hudson, along with many other rivers and bays along the U.S. East Coast, became laden with soil and sand.
The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite passed over the region on August 30, 2011 just two days after Irene unleashed extremely heavy rains, and captured this true-color image.
In this image, the Hudson River as well as its major tributary, the Mohawk River, appears as distinct muddy-brown lines set against a green background. Dark tan sediment spills from the Hudson River into New York Harbor, especially the Upper New York Bay. In the western section of the harbor, Raritan Bay is covered with a dark layer of sediment which flows from the tan-colored Raritan River. These muddy waters flow into the Atlantic Ocean, and darken the waters off the coastline. Further east a light tan plume of sediment flows into the Atlantic Ocean from the mud-brown Connecticut River.
Rolling over the top image reveals a much different picture. This second image was captured by the MODIS aboard NASA’s Terra satellite on July 31, 2011. In this image, the Hudson River appears as a deep blue trace against a green background. The Mohawk River, which feeds the Hudson, cannot be easily visualized and, to the east, the Connecticut River is only a faint blue line. New York Harbor is clear, with no sediment visible from either Upper New York Bay or Raritan Harbor.
David Ralson, a coastal oceanographer from the Woods Hole Oceanographic Institution, was quoted as saying “The sediment flux from Irene is really massive…unusual but not unheard of. One big event like this can move and deposit as much sediment as you might get in several years of regular flow on the Hudson”.
Besides soil and sand, flooding rivers can carry storm debris, broken tree limbs, sewage, pesticides and excess fertilizer. The last three contaminants can contribute to poor water quality and promote algae blooms. Heavy sediment can also negatively affect coastal shipping channels, fisheries and recreational use of rivers.
Date Acquired: 8/30/2011
Resolutions: 500m ( B),
Bands Used: 1,4,3
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC