Sunday, April 12, 2015

Catastrophic Ecological Risk in San Leandro Bay

"...the Seabird Massacre illustrates that greater awareness is needed by everyone."

Clapper rail (c/o Wikipedia)
The Alameda Seabird Massacre of 2015 has revealed the dawning of a new era of catastrophic ecological risk for San Leandro Bay and the birds and marine life that depend upon this habitat for their existence. The endangered clapper rail is among the species that live in this threatened habitat.

My research indicates that the mysterious "Mystery Goo" deaths of three hundred seabirds in January is tied to the plume of greyish-tan sludge I observed the previous October, described elsewhere on this web site (Click here for details), where I present the only plausible theory thus far advanced explaining the cause and source of the so-called "Mystery Bird Goo".

This mass execution of seabirds is under investigation by California's Department of Fish and Wildlife, but it is clear the material that killed them is of human origin. Laboratory analysis shows the gooey grey material matches drilling fluid used in earth-boring municipal projects such as laying conduit and sewer line.

But there is a bigger picture. The Bird Goo deaths are symptomatic of a systemic threat to Bay Area marine habit. Drought, dredging, street run-off and the use of toxic chemicals to control algae in Alameda's lagoons are all involved, but ignorance and indifference also play a role. This blog seeks to shed light on all these elements of threat to Bay Area marine life and habitat, not just "Bird Goo."

Rowers on Oakland-Alameda Estuary

The Role of Ignorance and Indifference
If you are taking a rowing class in the Oakland-Alameda Estuary, do you notice that flock of black birds you've been plowing through? Yes, the ones that make that whistling sound as their wings pump the air, scrambling to get out of your way. Those are  migrating surf scoters.

by Alan D. Wilson - NaturesPicsOnline
Surf scoters come to San Leandro Bay every year to escape the cold and fatten up for their return flight home: See Wikipedia on Surf Scoters. They're not yet endangered, but their numbers have been cut in half, thanks to human disregard and carelessness like the 2007 Coso Busan oil spill. (Click here for details on the Cosco Busan Oil Spill.)

Rowers need to avoid disturbing the waterfowl, but the Alameda Seabird Massacre illustrates how greater awareness is needed by everyone, not just rowing crews.

Tidal Currents
Tidal currents determined where the plume of sludge I observed last October was carried. A review of the currents surrounding Alameda zeroes-in on the magnitude of the problem.

Refer to Image 1fx below. The colored arrows show the direction of currents around Alameda Island. I know this from 13 years of observation during walks around the Island and from my ongoing research using NOAA* tidal charts. The red arrows indicate my observations of the sludge plume on October 12, 2104, from about 3:45PM until about 6:30PM. The blue arrow is the presumed flow of the sludge prior to my first observation, and the green arrows are my prediction of flows after it got dark.
Path of Toxic Plume

Naively, I had initially thought the sludge plume was carried all the way out through the Golden Gate Bridge after I left, but the NOAA charts indicate the tide reversed at 9:21PM. There wasn't enough time for the sludge to make it much farther than the mouth of the Estuary. From the speed of the plume and the distance to San Francisco Bay, not much of it could have cleared the western tip of Alameda Island before the tide reversed.

As indicated by the green arrows, around 9:30 the plume could have gone in three directions: a) south toward San Leandro and Hayward, b) south, then east along Alameda's south shore or c) due east, right back up the Oakland-Alameda Estuary. The strong current where the Estuary meets the San Francisco Bay would have pulled the vast majority of the plume right back where it came from--to San Leandro Bay.

Then, because of the strong Oakland-Alameda ship channel current, the bulk of the sludge kept going back and forth in the Estuary between San Landro Bay and San Francisco Bay, day after day, week after week, until hundreds of birds were saturated with the goo and began to die.

If, as I maintain elsewhere in this blog, the goo is partially a surfactant, it would have taken repeated exposures for the material to accumulate sufficiently to be lethal. The "goo" is not a one-time exposure event, but an accumulation of months of repeated exposuresa, layer upon layer, of some clarifying foming agent, drilling mud and surfactant imbeded with the various dissolved and undissolved solids that is was designed to adsorb**.

Water depth and volume determine the strength of these currents. Several years ago the Oakland ship channel was deepened from 42 feet to 50 feet. As would be expected, the tide in the Oakland-Alameda Estuary rips along much faster than anywhere else along Alameda's shoreline. The unintended consequence: an ecological death trap for endangered species in San Leandro Bay.

According to a city engineer, the discharge from Alameda's finger lagoons had always gone due south, toward the Hayward tidal flats. On the day my friend and I saw the plume, that certainly was not the case, and I suspect this is a permanent change in tidal currents because of a build-up of sediment off Alameda's southern shoreline, as illustrated by Images 1w, 1z? and 1zk.

The shallow areas are tan to beige and the deepest areas are dark blue. The shallowest area is just west of the Otis Street Bridge, where the portals for two lagoons empty into the Alameda-Bay Farm Island channel.

Note also the shallow areas in San Leandro Bay, where two deltas have been formed by effluent from the four natural estuaries. Sediment is being delivered to San Lenadro Bay daily from nearby streets and neighborhoods when people water lawns and wash cars. When it rains, the high volume flushes these sediments farther out, into the estuaries and into San Francisco Bay. During drought, this flushing doesn't occur, and sediment accumulates. Deltas grow larger.

As shown in Images 1z? and 1zk, A man-made delta appears to be forming in the Alameda-Bay Farm channel. This delta is man-made because the sediments come primarily from the two nearby lagoon weirs. The lack of spring rains would naturally accelerate this accumulation of sediment, and it is logical that this build-up would play a key role in offshore tidal currents and could help in accounting for the shift that surprised the city engineer.

An Alarming Conclusion
The alarming consequence of this shift in prevailing tidal currents is that toxic effluent from Alameda's finger lagoons is being drawn by the strong Estuary tidal current through San Leandro Bay, causing an unprecedented, potentially catastrophic threat to the marine ecosystem there and particularly to endangered species such as the clapper rail. In a separate post I have enumerated a list of birds I have personally observed in San Leandro Bay. There are many, many more.

The depth of the ship channel isn't going to change, and, short of a series of torrential storms, the sediment build-up isn't going away. So, to prevent catastrophic damage to the marine ecosystem of San Leandro Bay, we must STOP USING CHEMICALS IN ALAMEDA'S FINGER LAGOONS.

*National Oceanic and Atmospheric Administration
**Merriam-WebsterDefinition of ADSORPTION :the adhesion in an extremely thin layer of molecules (as of gases, solutes, or liquids) to the surfaces of solid bodies or liquids with which they are in contact — compare absorption

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