Last week’s heavy rains have made a change in the water off the Exploratorium’s decks and throughout San Francisco Bay. The water is muddy brown, thanks to sediment pouring downstream through creeks around the Bay and, most significantly, from the Delta, the confluence of the Sacramento and San Joaquin rivers that lies 40 miles inland.
The water is thick with debris, including plants that have broken loose and washed down with the current. These plants don’t live in the salty Bay, so they’re clearly from fresher waters upstream. In this photo you see a mat of tules, the tall reeds once used by local tribes to build canoes and huts, and water hyacinth, a South American water plant that now chokes many of the Delta’s waterways.
Looking through our Color of Water exhibit, you can compare the recent water color (2/15/17, left) with that on 3/28/16 (right), when the water was its more characteristic soupy green, colored by microscopic plant plankton.
