An interesting bottom – (former) Salt Pond A17


After a four-month hiatus I have resumed my kite aerial photography in the South Bay. The short days of winter were devoted to work on my book about the South Bay and a variety of little, barking tasks. So it was great to be out in the open again in the late afternoons of spring.

Salt Pond A17

Salt Pond A17 at high tide with a view of the facility controlling flow to Salt Pond A16.

My return was occasioned by a desire to photograph the recently breached Salt Pond A17 before nesting season put it off limits until September. I had not previously paid much attention to A17, which lies just south of Coyote Creek across from the abandoned hamlet of Drawbridge. The pond was returned to tidal flow last October and it is through A17 that water is provided to (former) Salt Pond A16. This latter pond has recently had a rather extensive makeover with a substantial inlet control station with fish screen, new islands and shallows created for avian habitat, and a new siphon to provide water for the New Chicago Marsh. Given that A17 was now filled by the tides twice a day folks were interested in how natural sediment, a precious commodity in the South Bay, was accumulating.

Salt Pond A17

Dredge marks along the ponds borrow ditch, with some showing the color of halophiles.

My first trip to A17 was ill timed regarding the tides so I captured a few shots of the filled pond, which looked very much like any other pond filled with bay water, and then took some shots of the new flow control facility. I returned a week later to catch A17 at low tide. Here I expected, and found, a pond bottom acquiring the natural colors and textures of natural bay flows – the patina of a thin biofilm here and there and the muted green grays of sediment. What I did not anticipate was a lively and fairly widespread scattering of small, bright pools of red, orange, and pink water. These must be stable pockets of highly saline water supporting populations of halophiles. It is a real surprise (if I am reading it correctly) to find that these little communities are remaining coherent through cycles of tidal inundation, testimony to the density of the concentrated brine and/or the gentleness of the tides. In any event it made for much more lively photographs than I imagined.

Salt Pond A17

Pond bottom with mudflat biofilm patina colors accented by small pockets of (presumed) halophiles.

Here is a set of images from the session that I have posted to Flickr:



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