On October 26, 2014, there was a
special event at the Don Edwards San Francisco Bay National Wildlife
Refuge's Alviso Environmental Education Center in Alviso. It was the
launch of a new mobile phone audio tour of the Mallard Slough Trail in
the refuge. The tours are downloadable smartphone applications for
locations, currently five, on the San Francisco Bay Trail. They guide
you on a step-by-step tour, using the GPS in your smartphone to detect
your location and play an audio clip for that location, along with
photos and illustrations. The tours are narrated by Doug McConnell, who
hosted Bay Area Backroads
The Open Road
and is the founder of Convergence Media Productions. He wrote the
script for the tours. The tours were funded by a California Coastal
Conservancy grant. The apps were created by Canogle
Here are maps of the trails around the Alviso
This is a closeup of the map showing the Alviso trails around the
former salt ponds. Today's hike will follow the Mallard Slough Trail,
which is shown on the right in orange.
This is an old map from the Alviso
Marina County Park map. It shows how the ponds are numbered. Note the
Education Center on the lower right. Previously, the Mallard Slough
Trail ran around ponds A16 and A17 when they were still salt ponds. The
trail made a big U around a channel between the two ponds, ran along
the north and east sides of A17, and there was a gap between the end of
that U and the east levee. Now that channel is gone, and the levee
along the north and east sides of A17 has been breached and
The gap at the end of the U has been bridged. Compare it to the current
map above. Note the train tracks separating the Alviso Slough Loop
trails from the Mallard Slough Trail and the connector between the two.
Laura Thompson, right, Project Manager for the San Francisco Bay Trail
project, greets the visitors. On the left is Jennifer, who is with the
USFWS and will be helping to lead the tour.
Arthur Bart-Williams of Canogle introduces the mobile phone tour. He is
holding a smartphone connected to a speaker, so the group can hear it
without having to use their own phone. On the right is Denise, also
The tour begins behind the Environmental Education Center.
This bench overlooks New
This stop on a viewing platform talks about the history of New Chicago
These interpretive signs talk about New Chicago Marsh and the salt
A ramp leads down to the boardwalk crossing New Chicago Marsh.
Another stop is at this viewing platform on the marsh.
These are the wetlands of the marsh. Surrounding it is the community of
Alviso, which once was an independent town, but became annexed to San
Jose in 1968.
There are birds resting on islands in the marsh.
This is a view looking back across the marsh towards the Environmental
The boardwalk leads to the edge of the marsh. On the way is a stop at
the interpretive sign.
This sign talks about the endangered salt marsh harvest mouse and how
they depend on pickleweed, which is the vegetation in the marsh in
front of the sign.
The boardwalk leads to a ramp that goes up to the levee separating the
New Chicago Marsh from the former salt pond to the north.
This is the former salt pond, designated A16. There are artificial
islands in the pond created to provide resting places for birds where
they would be safe from land predators.
Another view of A16 shows more birds on an island and a tide gate along
This is the northeast corner of New Chicago Marsh.
On the bank of Pond A16 are two viewing platforms. In the background
are Mission Peak on the left, Mt. Allison in the center, and Monument
Peak on the right.
This is the corner of Pond A16. The plants on the right are part of the
garden at the Environmental Education Center.
There are picnic tables here at the northwest corner of New Chicago
The trail turns north to follow the levee between Pond A16 and Artesian
Slough. There is a floating platform on Artesian Slough.
Artesian Slough is the outfall for the San Jose/Santa Clara Water
Pollution Control Plant. Highly treated wastewater is discharged into
the slough. This creates a freshwater environment in the upper parts of
This is a large viewing platform on A16.
There is another smaller viewing platform on A16.
This is a view of the islands and birds on A16.
This is a view of Artesian Slough, with water treatment ponds on the
This is a zoom-in view of the birds on an island in A16, showing there
is a large number of white pelicans here.
This satellite view from Google maps shows the hike so far in blue,
from the Environmental Education Center ("EEC") at the bottom, across
the New Chicago Marsh, to the levee around A16 on the upper left, with
Artesian Slough on the right. You can see the viewing platforms
("VP's") on A16 and the slough.
This is a tide gate on A16, connecting it to Artesian Slough.
This is the outlet pipe of the tide gate on Artesian Slough.
The trail curves around a large marsh along Artesian Slough.
There are more bird-covered islands in pond A16.
Near this bend in the trail is a submerged island covered with birds.
Seagulls and ducks are resting on this partially-submerged island. In
the background are the Sunnyvale Baylands and Moffett Field.
This stop is at a viewing platform with interpretive signs on A16.
This talks about restoration of salt ponds like A16 to make them more
friendly for wildlife. Tide gates let Bay waters flow in and out of
A16, so the waters are the same salinity as the Bay. The lower salinity
has doubled the amount of wildlife in the pond.
This sign talks about the wildlife in the pond, ranging from tiny brine
shrimp to fish to birds.
This sign talks about the salt-tolerant algae and bacteria that live in
the highly-saline salt ponds.
The trail wraps around the marsh.
This pond was used as a turn-around basin for the dredge that was used
to maintain the salt pond levees.
The trail round a corner of A16. Somebody has placed sticks in the
This Google satellite view shows the route from the tide gate ("TG"),
past the viewing platform ("VP") to the dredge pond, and beyond.
Artesian Slough is mislabeled as Coyote Creek.
The trail reaches the next pond,
designated A17. The levee that used to run around the east side of A17
has been obliterated, with only isolated mounds left, making travel on
the east side impossible. The channel in the middle used to join A17
and A16. The levee to the left of the channel used to be part of the
U-shaped trail mentioned above. The new trail cuts across blocks the
channel, and the northern part of the U-shaped trail has been
Ahead is the busy train track, used by freight and commuter trains.
This is the train passing by the northwest corner of A16.
The trail heads towards a large building on A17.
This building and structure on A17 is a tide gate, regulating the flow
between A17 and A16. A17 is open to unregulated tidal flow, while tide
gates control the level of A16, allowing tidal waters to flow through
it, but keeping the water level relatively constant, like a lake.
This is pond A17 by the tide gate.
This Google satellite view shows
the start of A17 on the lower right, with the blocked channel at the
end. The north part of the U-shaped trail between A16 and A17 is now
gone. The remnants of the levee on the east side of A17 are next to
Artesian Slough (not Coyote Creek). The trail makes a jog over a new
levee to reach the tide gate ("TG") on A17. To the left is the crossing
("Xng") to reach the Alviso Slough Loop Trail along pond A15. This will
be seen later.
The trail rounds the corner of A17 and approaches the train tracks.
There's an old service catwalk leading across the marsh to the train
tracks. The catwalk is closed to the public.
This is the north part of pond A17. It must be high tide, as the pond
is nearly full.
The trail approaches Coyote Creek. A concrete train bridge over the
creek can be seen. On the other side of Coyote Creek are old
dilapidated buildings. They are what remains of the ghost town of
This is Coyote Creek and the train bridge crossing over it. Coyote
Creek is a tidal slough here. It is a rising high tide, as the water is
flowing upstream. It is illegal and dangerous to cross over the bridge.
The tops of the old buildings of Drawbridge can be
seen beyond the bridge. There used to be actual drawbridges here,
which is how the town got its name.
This is our stop where we hear the story of Drawbridge.
On the other side of Coyote Creek
is Station Island. This sign talks about the town of Drawbridge that
was on the island. The first building was a cabin built in 1876 by the
South Pacific Coast Railroad, which housed the operator of the
drawbridges on both sides of the island. Wildlife and fish were
abundant, which attracted hunters and fishermen to the island. There
were 90 buildings on the island by 1926.
This talks about the demise of Drawbridge due to the deteriorating
environment and the recent efforts to restore the environment, though
not the town.
These are the decaying buildings of Drawbridge on Station Island, which
is no longer accessible to the public. The buildings can be seen from
the commuter trains that cross the island daily.
This is the levee between Coyote Creek on the left and pond A17 on the
right. The levee used to run around the pond, but now stops a short
distance ahead, as there is a large breech in the levee, allowing tidal
waters from Coyote Creek to flow into A17.
This Google satellite view shows the route we took up the west side of
A17 to the bridge over Coyote Creek. The large breach in the levee of
A17 is at top center.
This Google satellite view farther north up Station Island shows some
of the remaining buildings of Drawbridge.
As we head south on the trail, we pass a train crossing that leads to
the Alviso Slough Loop around pond A15. Technically and legally this is
not an official crossing, for liability reasons. If you cross, it's at
your own risk. Watch for trains, as this is a busy track.
The trail south on the west side of pond A16 is ruler-straight as it
parallels the railroad tracks.
There are flocks of sandpipers feeding on the shore of A16.
Across the railroad tracks is pond A13, which has been lowered,
revealing more of the pond's bottom, creating dry land. The pond depths
are being adjusted to create varying environments to benefit different
At the southwest corner of pond A16 is a bench. Behind it is New
This is the levee trail running along the south side of A16, separating
it from New Chicago Marsh.
Ahead on the right is a tide gate where water is allowed to flow from
pond A16 into New Chicago Marsh. The trail loop ends at the
Environmental Education Center.
This shows the last part of the route around the corner of A16, past
the tide gate between A16 and New Chicago Marsh, back to the
Environmental Education Center.
This is the entrance to the Environmental Education Center.
Inside the Environmental Education Center are exhibits on the Bay, its
history, and wildlife.
There's a replica of the type of reed hut made by the native people who
lived by the Bay.
These panels talk about how the Bay has changed over time.
This exhibit talks about preventing pollution of the Bay. Next to it is
a staircase leading upstairs to a viewing area.
This map shows a closeup of the area around the Environmental Education
Center. The Marsh View Trail begins south of the parking lot and runs
along the edge of New Chicago Marsh to a parking lot on Grand Blvd.
This interpretive sign is near the start of the Marsh View Trail.
Along the Marsh View Trail is this pavilion, used for outdoor classes.