In the wake of Hurricane Irene and Tropical Storm Lee, sediment choked the Hudson River in New York City in early September 2011. The river’s unusual brown or reddish hue was likely driven by runoff occurring upstate.
The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured these natural-color images of the Hudson River and East River. Both images are rotated and north is at right. The top image shows the area on September 12, 2011. The bottom image shows the same place about a year earlier, on September 2, 2010. In September 2010, the water is navy blue. One year later, the water is muddy brown, and the brown hue appears more intense in the Hudson River than in the nearby East River.
Flooding not only raises river levels, but also increases the amount of sediment they carry. Torrential rain eats away at the ground, washing mud and debris into streams. After it is deposited into a river, sediment may sink to the bottom of the riverbed, or may flow with the water toward the sea. Multiple rivers feed the Hudson, and some of the sediment winding up in the river in early September 2011 included reddish clays from the Catskills region, The New York Times reported.
NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott.
The largest river on the planet, the Amazon, forms from the confluence of the Solimões (the upper Amazon River) and the Negro at the Brazilian city of Manaus in central Amazonas. At the river confluence, the muddy, tan-colored waters of the Solimões meet the “black” water of the Negro River. The unique mixing zone where the waters meet extends downstream through the rainforest for hundreds of kilometers, and is a famous attraction for tourists from all over the world. The tourism contributes to substantial growth in the city of Manaus. Twenty years ago the large park near the city center (center) lay on the eastern outskirts of Manaus.