Archive for the ‘Oakland streams and water’ Category

The mine drainage of Leona Creek revisited

31 July 2017

Over the years I’ve done a lot of poking around Leona Heights, the large hill looming over the south end of the Warren Freeway. You’d think I have a nice photo after all this time, but instead here’s a vertical view from Google Maps, terrain view. It shows the area between Horseshoe Creek, at the top, and the former Leona Quarry at the lower right.

The hillside is deeply eroded by several steep gullies, all of which still have running water in them at this time of year. Those fascinate me. And the satellite view of the same area shows how much of it is forest, which also fascinates me.

Most of this land is inaccessible. There’s only two fire roads, few trails, and very steep slopes well guarded by brush and poison oak. Apparently the city owns much of it.

And here’s the stream map to help with the creek names, because they’re confusing. Each of the Leona Heights gullies is interesting, and I’ll be showing them to you in coming weeks, but this week I’ll focus on the one labeled Leona Creek.

The streams in these hills all feed Lion Creek, originally named Arroyo del Leon. The rules of river names say that the name of a stream applies to the most vigorous branch, and if the stream splits into branches of the same vigor the name can be arbitrarily assigned to one branch, or none. Thus the upstream end of Sausal Creek is where Shepard Creek and Palo Seco Creek join. So on this map I’m extending Lion Creek up its northernmost branch (although it may well be that by this criterion Horseshoe Creek should be Lion Creek). People also talk about “Leona Creek,” sometimes applying the name to all of Lion Creek and sometimes applying it to the nameless creek that has the former Leona Mine on it. Because the mine site is so important, I’m giving that particular stream the name Leona Creek.

This creek once had potential. It has a nice catchment, seen here from the Merritt College parking lot toward the north end of Ridgemont Avenue. The woods are impenetrable.

But then the creek reaches the old mine.

By early last year, the mine site had been fixed up so it looked clean.

And down below the mine the stream looked pretty good.

But as of a couple weeks ago, it was back to its old trick: acid mine drainage.

What we’re looking at is yellow and orange iron oxides, precipitated out of the acidic water as it’s neutralized. They aren’t poisonous in themselves, and the water won’t eat the flesh off your fingers. But other metals are dissolved in drainage water besides iron, which are more toxic. I don’t have any chemical data from the water, so I can’t address the true hazard. But this stuff is harmful in other ways, specifically by blanketing the streambed so that living things can’t live on and in the gravel like they’re used to — insects and insect larvae, which feed other insects and birds and so on.

Acid drainage is natural in the Leona Heights, to a certain degree. The rocks hold a lot of pyrite, which oxidizes to yield sulfuric acid, so there’s always a little acid around. The mine, however, opened up the richest part of the hill and gave it access to oxygen.

The raw chemistry of pyrite oxidation is not that fast. But sulfur-oxidizing bacteria make their living by eating pyrite and pissing out acid, and the old mine is like a giant party condo for them. They won’t stop for anything short of encasing the whole hillside in concrete. And we won’t do that.

Oakland geology ramble 4: Uptown to Montclair

24 July 2017

This five-mile urban hike is more of a terrain-and-streams ramble than a bedrock ramble. It climbs over 700 feet, winding through the watersheds that freshen Lake Merritt and traversing some of Piedmont’s wildest land. Although I’ve walked the route both ways, I’ll present it here from west to east.

The route goes from the 19th Street BART station to the heart of Montclair on La Salle Avenue, where every 20 minutes the 33 bus will take you straight back to the starting point. Or vice versa.

The terrain map shows the watersheds and drainage divides along the way.

This route is just one of several good possibilities. I have a thing about views, so I favor ridge roads that thread the divides between stream valleys. There are three streams here: Pleasant Valley/Bushy Dell Creeks (Grand Avenue), Wildwood Creek (Lakeshore Avenue), and Indian Gulch Creek (Trestle Glen Road). My route follows Warfield Ridge, the divide between the first two streams. The eastern alternative would go up Longridge Road, the divide between the last two streams. And, of course, one could take the low roads that follow the three streams instead. I leave those as exercises for the reader.

For completeness’ sake, here’s the geologic map. The blue areas are bedrock and the other colors represent various bodies of sediment.

The interaction of geology and terrain adds interest to the hike, but truth be told, the elegant and extravagant residences along the way are just as attractive as the geology.

On Broadway and Grand Avenue, you tread the level ground of the late Pleistocene marine terrace (Qmt) along the foot of the Fan (Qpaf), the large body of Pleistocene alluvium that’s one of Oakland’s most distinctive geomorphic features.

To the right of the Grand Lake Theater, the tall red-and-white building stands on Warfield Ridge. Behind it is Round Top. Cut to the right of the theater and make your way to, then up Warfield Avenue. That building houses the Grandview Apartments, and it’s well named.

Warfield, as I said, is a ridge road. It goes up and down a bit, but mostly up.

If you’re like me you’ll want to catch your breath every now and then. There are views on all sides. Pause and enjoy them. To the left is Pleasant Valley.

To the right is Wildwood Valley.

And behind is where you came.

Stay on Warfield all the way to its upper end, at split-level Wildwood Avenue. Go on up Wildwood. Right after you skirt Witter Field, in the valley of Bushy Dell Creek, you’ll enter the Wildwood Creek watershed for real, and also finally encounter bedrock.

It’s humble stuff, Franciscan sandstone. But it makes good crushed stone, and it supported several quarries before Piedmont took on its current identity. Take a closer look at the terrain here.

South of the blue line, you’ll see four small gulches eroded into this rocky hillside. The third one was a rock quarry that was later made into Oakland’s Davie Tennis Stadium. The others remained unexploited and are now thickly wooded. All four have running water still, thanks to our wet winter.

I picked the route that goes through the rocky headlands between these gulches. Turn right off Wildwood to Wildwood Gardens, and wend your way through this elegant neighborhood, across the top of the Wildwood Creek watershed, to the start of La Salle Avenue. Stay on La Salle all the way to Montclair.

La Salle crosses a fairly flat part of Piedmont, then leads along the rim of Indian Gulch, the village’s greenest and most secluded district. The road then goes up the floor of the stream’s middle branch. At its intersection with Hampton Road is a newly refurbished sports park where you can (and should) refill your water bottle. Higher up this little valley is a former reservoir named Tyson Lake. You can’t get to it.

La Salle becomes pretty steep here as you climb out of the valley and crest the highest ridge at about 725 feet elevation. The change in grade is the clearest signal that the bedrock is changing, according to the map, from Franciscan sandstone to Franciscan melange. But you can’t see that, either — there are no exposures of the melange along this road.

Instead you can see the high valley of Montclair, home of the Hayward fault, as you finally start down. A walkway painted on the road helps keep the locals’ cars back. In that respect Oakland is more walk-friendly than Piedmont.

And here’s the view back from the end of the line.

The Hayward fault is mapped right on the corner of La Salle and Moraga. You’ll see the offset curbs much better on Medau Place, though, one block north.

Brooklyn Landing, Brooklyn Creek

19 June 2017

The first Western inhabitants of this area, the Peralta family, were horse people rather than boat people. They did much of their business, with the mission and the town of San Jose in the South Bay, by land. When they did use boats, it was to transport hides and tallow from their ranch, using an embarcadero on San Antonio Creek to the east of the slough that’s now called Lake Merritt. Unlike the slough, the creek was navigable there, being several feet deep even at low tide. Although there was a better spot on the west side of the slough, the rancheros would have had to haul their wagons through the hills around the slough to reach it. They preferred the simple downhill route from their hacienda. (The Americans, with the larger vision of newcomers, took that other spot and made it the mighty harbor we know today.)

Later the town of Brooklyn formed around the Peraltas’ landing. The map below, from 1857, shows San Antonio Creek winding its way west from the Brooklyn landing (thanks Wikipedia).

Incidentally this was a true creek, according to long-standing usage in Britain and colonial America — “a small, narrow tidal inlet or estuary” as the AGI Glossary of Geology puts it. Today we use “creek” for any small stream . . . like 14th Avenue Creek (as the watershed people call it), which flowed down to the landing. If this creek had another name, maps don’t record it, and anyway I feel like calling it Brooklyn Creek. The first road, named Commerce Street, ran up along that creek. Today you can drive up it under its new name of 14th Avenue (or ride the odd little 96 line) and still see the valley walls on either side.

Long story short, the land was built out and the little harbor disappeared as first the railroads, then the freeway and then BART ran through. The geologic map shows all that as artificial fill (af).

This was once the omphalos of East Oakland. Two different horse-drawn railroads had terminals here, the Oakland, Brooklyn and Fruitvale Railroad and the Brooklyn and Fruitvale Railroad. Today little remains to mark this former place. It was still a destination when the San Francisco and Oakland Railroad sited a heavy-rail station here in 1864, and a single palm tree from the old days grows yet amid today’s anonymous tracks. And there’s tiny, seedy Vantage Point Park on the low rise that once overlooked our first harbor.

Brooklyn Creek is fully culverted now. Its outlet is probably across the transport corridor at this little cutout along the shoreline.

Today San Antonio Creek is no longer even an entity. The waterway has been replaced entirely by Oakland’s dredged-out Inner Harbor and Brooklyn Basin.

Stonehurst Creek

8 May 2017

Stonehurst Creek isn’t really a creek, just a stormwater channel. But there it is on the watershed map, with a name and everything. Of the 13 named tributaries that feed San Leandro Creek, it’s the last one before the Bay. And it’s got potential.

I only discovered Stonehurst Creek because one day last June I set out to follow the Union Pacific track under the 880 freeway. (And pioneer a scenic route to the Cleophus Quealy tasting room.)

The tracks parallel 105th Avenue, and of course it’s private property. I advise you not to go there. If you choose to ignore my advice, however, the easiest access in Oakland is from Knight Street. You walk to the left of the tracks, near the drainage ditch that is Stonehurst Creek.

A maintenance road runs along the far side. This photo, from June 2016 at the height of the drought, shows there’s always water here.

This spring the area’s pretty lush in comparison. And if you look back, it’s not devoid of scenery.

On the other side of the freeway, the tracks cross San Leandro Creek. From there you can spot the mouth of Stonehurst Creek, looking almost creeklike.

I’m telling you all this because the route could become more of a destination under the newly released San Leandro Creek Trail Master Plan Study, a long-term vision of how we can get people back to Oakland’s largest and most important stream.

Because San Leandro Creek is very hard to access upstream from here, there would need to be a detour, and Stonehurst Creek would be handy for that. The Study mentions the “potential restoration of Stonehurst Creek,” which sounds funny because old maps don’t show any creek at all here to “restore.” Apparently the technical meaning of restoration includes building a natural creek from scratch.

You can continue down the tracks past Davis Street and turn right to get to Doolittle Drive, then go north to make your way to Cleophus Quealy — I mean, *I* can. The point is to arrive thirsty. But while we’re on the bridge, let’s look at San Leandro Creek.

Downstream, there’s a maintenance road on the left bank that could be opened up nicely to foot and bike traffic, and on the right bank a tidy, bare open space at the end of Empire Road that could become more of a park.

Upstream is more forbidding: there’s a maintenance road there too, but it’s down in the streambed, below the right bank, and couldn’t easily be opened to the public. Hence the need for a detour up Stonehurst Creek. Conceivably you could walk it in the dry season, but I would advise against that.

The San Leandro Creek Trail Master Plan Study says, “There is a large open space below I-880 that could be used creatively.”

And there are some visionaries hard at work doing that already.

Perhaps you would find their efforts as arresting as I do. Perhaps you would be dumbstruck, as I was. Perhaps you would exclaim, as people who explore Oakland often do, “There’s a there here!”

No matter where you go in Oakland, this town can excite some form of wordless delight.