Archive for the ‘oakland water’ Category

Triple creek junction

17 March 2015

A while ago I featured the casting ponds at McCrea Memorial Park, in the valley of upper Lion Creek. I didn’t poke further downstream at the time, but since then I have. The creek runs alongside a pair of small concrete “trout ponds,” cunningly made with cobble-lined runnels that would send a lifegiving trickle through them if there was enough streamflow, which there isn’t, to sustain fish, which there aren’t any of.

leonack-troutponds

The lower pond did have enough water in it to interest a mallard couple. The male kept watch on me as the female gorged on duckweed.

To the left of that photo, just over a low ridge and behind a fence, the iron-stained waters of Sulfur Mine creek exit a pipe.

sulfurmineck-outlet

Farther down, it joins Lion Creek and the combined watercourse enters a tunnel beneath the Warren Freeway. I haven’t gone into it, but people clearly do.

sulfurmine-lion-ck-junction

If you cross the freeway on the little-used pedestrian overpass, you might expect to find the creek on the other side. Instead you’ll see Horseshoe Creek coming out of its canyon in Leona Heights Park and entering its own final conduit.

horseshoeck-mouth

Where the two creeks meet must once have been a cheerful place. Today it must be a black and dismal one, visited only by rare daredevils. If the tunnels aren’t screened, perhaps they can crawl all the way down to where Lion Creek reemerges, at Lake Aliso at Mills College, in a wretched feat of urban spelunking.

Seminary Creek at Mills College

14 February 2015

The third creek running through Mills College is Seminary Creek. It gets its name not just from Mills, but from the Beulah Heights district that forms its headwaters. On the 1897 USGS topo map it’s the dashed blue line, signifying an intermittent stream, running due south to East Creek (now named Lion Creek).

mills-SemCk-topo

Nowadays it’s almost entirely culverted. Not only that, it’s been kidnapped! The Oakland Museum of California’s creek map shows the creek as being redirected away from Lion Creek. Today it runs just north of Seminary Avenue to a channel called East Creek Slough.

lion-seminarycreekmap

What glory the creek still has today is evident only on the Mills College grounds. It ducks between lobes 6 (Maxwell Park) and 7 (Mills) of the Fan next to MacArthur Boulevard, but a close look at the topography suggests that a landslide or earthquake could easily have made it spill to the east of lobe 7 (past the triangle marked “30” on the stream map). Be all that as it may, the creek daylights just where MacArthur curves west.

mills-SemCk-intro

It then wanders a couple hundred yards through a nice quiet forest, mostly eucalyptus. Other than putting a parking lot over half its course, the college appears to have left Seminary Creek alone.

mills-SemCk

When it hits MacArthur, at 57th Avenue, Seminary Creek disappears. Here’s the last sight of it, from the MacArthur side. Here’s where the stream got kidnapped.

mills-SemCk-outro

I’ve taken photos of the creek farther downstream, but it’s a nondescript ditch and now I feel sorry for it. So I’ll spare you.

Interestingly, the old map showed the creek as intermittent, but I’ve never seen it dry even after our three-years drought. As I mentioned about Chimes Creek, I think undergrounding Seminary Creek has kept it from evaporating.

Chimes Creek and the Hayward fault

7 February 2015

Chimes Creek is the second of the three streams in Mills College. It is said to get its name in reference to the college’s church bells. The sound would have traveled up the creek bed to the meadows behind Millsmont ridge. Today the freeway noise drowns them out. Here’s how it looked to the mapmakers of the U.S. Geological Survey in 1897—it’s represented by the dashed blue line in the middle. Below that is the same patch of land in Google Maps as of today.

chimescreekmap1897
chimescreekmapnow

The land has been changed substantially in the last 118 years, but the creek continues to drain its catchment. Let’s look at the changes from the top down:

  • The headwaters have been filled and paved and are now occupied by Viewcrest Drive.
  • The Leona Quarry removed all the overburden below a short stretch of the upper creek, exposing bare rock.
  • The flats beneath have been leveled and developed, and the creek is culverted.
  • Seminary Avenue has been widened and straightened, putting more of the creek underground.

All of these changes have added to the runoff seeking to enter the creek while constricting its course. A stream will respond by running higher and faster and eroding its banks.

I haven’t yet visited the highest part of the catchment. Here’s a look at it down Altamont Avenue.

chimescreek1

The original creekbed is high above the left edge of the quarry, and the creek ran toward the lowest part of the foreground. Next is the view one block over, at Delmont Avenue and Hillmont Drive looking north. The creek comes out of its culvert behind the houses on the left.

chimescreek2

I should note that the Hayward fault is mapped running right up the valley to this spot. That’s an important detail that no one seems to acknowledge. For my purposes in this post, it means that Chimes Creek is probably cutting downward through fault gouge, the finely ground material that faults make all over California.

Farther downstream, this is looking across the creek valley at Nairobi Place. The sides are quite high here because the stream cuts downward rather strongly.

chimescreek3

The presence of the Hayward fault also explains why the right (opposite) bank of the creek valley is elevated above its surroundings—it’s not a levee, but rather a pressure ridge. Farther downstream along Oakdale Avenue, the valley is at its deepest.

chimescreek4

The lots along Hillmont Drive, across the creek, are being undermined as the invigorated stream does its work.

chimescreek5

I’ve love a good look at this material, but I’ll probably never get the chance. The geologic map shows this area as the northernmost splinter of the San Leandro Gabbro.

The creek enters a culvert under Seminary Avenue here . . .

chimescreek6

. . . and emerges here on the grounds of Mills College for a couple hundred feet. Then it enters its last culvert and joins Lion Creek underground.

chimescreek-mills

The Chimes Creek Neighbors site has thorough documentation of the human squabbling over this much put-upon watercourse. The neighbors know it as a permanent creek, although the 1897 map showed it as intermittent except for its lower reach on the Mills College campus. I suspect that the land-use changes of the last century have turned it into a permanent and more powerful stream.

Lion Creek in Mills College

29 January 2015

Lion Creek was once an Oakland landmark, named for the mountain lions and their habitat high in its catchment. Today it sneaks its way, mostly underground in culverts, to the bay. Didn’t use to be like that. Nowadays, the only place the creek is cherished and well cared for is on the Mills College campus. Here’s a brief tour from top to bottom.

At the top (west) end of the campus, Lion Creek feeds Lake Aliso, as I mentioned a few posts back. I was astonished on my last visit to find that the lake has been drained! This is the view from the dam. It’s a temporary calamity for the lake, but now the creek is visible.

aliso-drained1

I’ve been trying to reach someone at Mills to tell me the story without success. Maybe one of you knows. In this close-up, you can see that the water is yellow, I assume from the rehabilitation work going on upstream at the former sulfur mine.

aliso-drained2

And maybe the lake is drained just to let that crap wash out to sea.

The creek is, to my mind, the aorta of the campus, the way Strawberry Creek is at UC Berkeley. The old oaks and bay trees are still in place as the creek meanders graciously west.

mills-lioncreek

Just before the old west entrance, the creek is culverted, curving left past a small lobe of the Fan on its way out.

mills-lion-ck-exit

And that’s it for Lion Creek, except for a little exposure along 64th Avenue by Bond Street, until it hits the old Coliseum Gardens property in its remade bed.

The Mills College high-grade blueschist block

14 January 2015

Longtime commenter artisancrafts reminded me, in a comment to my last post, that there’s a nice exposure of blueschist at the north edge of Mills College. Yesterday I easily located it by following his/her directions. First there’s the old railbed that once ran to Laundry Canyon. This stretch of it, which once continued down through the Fan parallel to High Street, used to be part of Courtland Street.

mills-railbed

At the spot in the distance where the sun shines across the roadbed is this lovely exposure, about 2 by 3 meters.

mills-bluschist1

It’s clearly worn by water, and a little concrete-lined ditch running along the uphill side of the roadbed feeds it. Following it upstream takes you right up to the 580 freeway abutment, where it veers north in a culvert. The stream is a mystery that I won’t try to solve today.

Back to the rock. Getting closer to it, you may not believe your camera. Clear blue skylight can do that.

mills-bluschist2

This closeup, showing tightly folded lamination in the cleft on the right edge of the first shot, is a truer indication of its color thanks to my camera’s flash.

mills-bluschist3

It’s classic blueschist, the largest outcrop of it I’ve seen in Oakland. Let’s call it blueschist-grade melange, what’s usually referred to in Franciscan circles as a high-grade block, and I’m very pleased to know that we have one in town.


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