pahavit (pahavit) wrote,

Permanente Creek 4: Diversion Channel

Permanente Creek 4: Diversion Channel

Permanente Creek helps form a border between Los Altos and Mountain View. During the 1950s and 1980s, Permanente Creek rose over its banks in several areas, causing millions of dollars in damage to homes and businesses.

The Permanente diversion channel, located downstream, was built to help control flooding of this creek during winter storms. This 1.3-mile-long concrete channel diverts high winter flows from Permanente Creek and empties into Stevens Creek, where it flows into San Francisco Bay. This diversion is active when Permanente Creek reaches high levels and provides flood protection for Mountain View and Los Altos.

D. and I walked the diversion channel recently. Here's what we saw, starting at Heritage Oaks Park in Los Altos. Here are our pics.

"Friends Forever."  I guess she and Tyesha aren't such good friends anymore cuz she left this behind at the park. 

Dry creek at Heritage Oaks Park.

Graffiti in the Portland Ave. tunnel at Heritage Oaks Park.  I guess it's funny if you're stoned. 

This section is full of tiny, skittering lizards. Here's one unwilling to leave its basking rock. It's only about 2" long, minus tail.

This type of channel is called a concrete trapezoid channel, after its cross-section shape. This stretch is full of gravel, dead leaves, weeds and small shrubs, washed in there from the natural channel just upstream during winter rains. The next flood will scour it all out once again.

We find an odd bridge to nowhere crossing the creek. It runs between chain-link fencing on both sides with no way to access it. Busy Miramonte Ave. is at one end, and the fence of someone's private back yard is at the other. 

A bit farther downstream, approaching the point of diversion.

The point of diversion.

During regular water flow, water goes down this pipe to continue Permanente Creek in a natural channel.

Viewed through grating, a little fig tree is growing at the bottom of the diversion basin. If left unattended, it will grow big enough to obstruct the water flow, and possibly crack the concrete.

The diversion controls up on the access path at the top of the channel.

Fences of rich people's back yards in ritzy Los Altos line the way.

Here's the ramp up to the path.

The path alongside the top of the channel.

A hydrangea pokes through a fence to say hello.

The fruit of a strawberry tree (Arbutus unedo).  This is not where strawberries come from.

We get glimpses into rich people's back yards.

A late summer's bounty of Asian pears overhangs the path.

Many of them have fallen off the boughs and litter the path.  We can smell the fermenting fruit in the hot sun from several yards away.

Blue plumbago flowers.

A black phoebe hangs around the edge of the channel.

A hummingbird is nearly invisible against the background foliage as it rests on a twig.

Ripening dates in the crown of a palm in someone's back yard abutting the path along the channel.

D. and I call this plant the curly-haired weed. There was a fair amount of it in the channel. We don't know what it is.

Trapped apples, fallen off someone's tree and caught between their backyard fence and the chain-link fence along the path.

Pittosporum seed pods.

Purple flowers.

Concrete u-frame channel near Georgina Blach Intermediate School.  The channel twists and turns a bit in this short stretch, and the u-shape channel reduces the sloshing of the floodwater until it can straighten out again and go back into the trapezoid channel.

Another one of the occasional access ramps can be seen on the left, in case the water department needs to launch a boat or get a vehicle down there.

Grapes grow on the fence at the school.  Alas, they are out of reach.

Grass seeds sprout in a small trickle of water in the channel while still attached to the fallen, dead stalks.

In the detritus of the channel east of the school we find a pumpkin plant.

A little farther along we find a second pumpkin plant.

Coming back we find a third pumpkin plant in the channel west of the school.  Come to the Permanente Creek Diversion Channel for all your jack-o-lantern needs!  

A redwood's tiny flowers.

One of three red-tailed hawks circling overhead.

Another stretch of dead, dried-up weeds.

Ferns find just enough moisture to survive in a drainage hole.

More curly-haired weed growing out of a drainage hole in the channel wall.

Some flowers growing from a crack in the concrete.

Summer survival can be determined by a matter of a mere couple of feet along here.  (They look like papyrus plants.)

Even here we find snails estivating for the summer. Imagine their surprise when the first flood of winter comes racing down the channel.

A scarlet skimmer dragonfly patrols his little patch of water.

People in Los Altos overwater their lawns and it pours from the storm drains into the channel.

Berries growing in the cool, damp shade under the Grant Road overpass.  Just a few yards away, weeds shrivel up and die in the hot sun.

Graffiti in the Grant Road overpass.

At the Grant Road overpass, we have crossed from Los Altos back into Mountain View. The East Bay Hills across the Bay are in the distance.

Mud dauber wasp nests under St. Giles Lane overcrossing.

Me in the channel. Nine feet deep.

Pipe feeding into the channel.

There are a number of them here and there.

"I shot an arrow into the air, it fell to earth I know not where . . ."  (Have you looked in the Permanente Creek Diversion Channel for it?  )

We also see a few baseballs, a golf ball, a wiffle-type ball, some tennis balls and a hackysack, in addition to the busted bowling pin and arrow.  Come to Permanente Creek Diversion Channel for all your sporting goods needs! 

In the channel, wet areas start showing up and give rise to stretches of greenery in distance. We must leave the channel and go up on the path to go any farther.

The channel becomes almost choked with vegetation.

Some kind of pipeline (possibly natural gas) goes upsy-daisy over the channel here.

Barbed wire is a good way to say, "Do not cllimb on the pipeline!"  

Path looking east, back the way we came.

Here's a scummy, stagnant part.

Ookie water.

That's a teddy bear and some peaches in the scum.

We find a lot of trash in the channel.

In addition to the mousetrap and broken scraper, we also find a discarded jack, a trowel and a screwdriver. Come to Permanente Creek Diversion Channel for all your (slightly used) hardware needs! 

An oak tree squeezed between the chain-link fence of the water department and the backyard fence of the house there. With nowhere else to go, the tree has grown to engulf the chain-link fence into itself.

Apples and a grapevine tendril overhang someone's backyard fence.

Another vine of purple grapes, out of reach.  I'll bet they're sour anyway. 

An unusual pinwheel spins cheerfully in a back yard.

At the Diericx Drive overcrossing.  It's nice to know the channel is not an orphan. 

That brown thing is the Highway 85 sound wall. On the other side of the highway is Stevens Creek, into which flows any water diverted down the channel from Permanente Creek.  The actual confluence is probably situated underneath the highway.

We ran out of path here, and the channel became too wet to walk down any farther. End of the line.

Tags: bird, dragonfly, field trip, graffiti, hummingbird, lizard, permanente creek, pumpkin, red-tailed hawk, whirlygig

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