Oakland Geology

Everybody walks around Lake Merritt. I do it all the time. But I got the wacky idea of a walk that circles the lake without “touching” it — sort of a “floor is molten lava” version — and pedestrian paths count. Here’s what that would look like.

That’s a fun walk through some fine neighborhoods, and about 1-1/2 miles longer than sticking to the shore. The only quibble is at Grand and Euclid: you might be safer from the lava if you left Grand a block west, up Bellevue, but you’d miss some rare little streets and a stairway.

Then I thought, What will it be like after a century or so of sea-level rise? How would people get around the swollen lake in 2100? Laying out that walk required more care. The forecasts of future sea levels vary widely — so much depends on Antarctica and human actions — but a summary by NASA puts the worst-case upper limit at 2 meters above today’s elevation by the year 2100.

You could walk all over the lake shore and eyeball 2 meters elevation — and I did do that — but fortunately there’s a better tool available at the Risk Finder site, by Climate Central. That’s where I compiled the map below (1200 x 1000), showing the areas around Lake Merritt that would be inundated by a 2-meter sea-level rise. (You’ll also find a big page of stuff about Oakland.)

The map shows we’d lose nearly all of the shoreline roads. Along the west arm of the lake, most of Lakeside Drive would go under, and the water would reach up Harrison all the way to Whole Foods.

In Lakeside Park, the bandstand and the whole bird sanctuary would be submerged, though the rest of the park is on a Pleistocene marine terrace and would stay dry.

The east end of the lake would really take a hit. Forget the pergola — all of Eastshore Park would turn into tidal wetland, and Splash Pad Park? It’d be just Splash Park.

Grand Avenue as far as Elwood we’d have to rename Grand Canal. All the properties lining Lake Park Avenue would get their feet wet, including the Grand Lake Theatre, and a bunch of shops on Lakeshore.

Down at the boat landing, E. 18th Street would be underwater all the way to Park Boulevard, wiping out the heart of that commercial district.

And the Lake Merritt Amphitheater would mostly go under, though the roadway — Lake Merritt Boulevard — would be fine. So would the pedestrian bridge, for what that’s worth.

The geologic map shows that the new wetlands around the lake would be in areas of artificial fill (af), and because fill isn’t built up any higher than strictly necessary, it’s vulnerable to rising seas. In planning my round-the-lake walk I kept things simple and assumed the roads in these areas will be abandoned (but see more below).

Walking around the lake in 2100, you’d have to give a wide berth to “Thomas L. Berkley Creek” under 20th Street, Glen Echo Creek under Harrison, Pleasant Valley and Trestle Glen Creeks under Grand Lake, and Park Boulevard Creek under E. 18th. These detours will put you up in the hills, because that part of town is either really flat or stairstep steep. On the positive side, that terrain (lobes 3 and 4 of the Fan) is what makes Adams Point, Lakeshore and Cleveland Heights so charming.

Given all that, I came up with this 2100 Walk Around Lake Merritt.

Notice that almost none of it actually “touches” the lake. The shoreline roads will be swamped, along with each of the stream valleys entering the lake. As I field-checked this walk by eyeball, at two places in particular it looked like you’d still need wellies. One spot is Sunset Cove, at the north end of Wayne where it meets Wesley Avenue (at the end of the word “Lakeshore” on the map).

If that’s off limits (and the inundation map says it is) you’d need to climb up Newton instead and come down Stow, which would definitely call for a pizza slice from Leaning Tower (if it’s still there in 2100) to get you over that hump.

The other spot is on Harrison at the Whole Foods. If Bay Place (the continuation of 27th Street) isn’t above water, you’d have to detour up Vernon and traverse the hills of Adams Point on Lee Street to get back down to Grand Avenue. But you might as well stay up high, because the only way across the freeway, short of climbing all the way up to the Chetwood Street overcrossing and back down Santa Clara (about a half-mile detour), is the amazing pedestrian/bike crossing at the end of Van Buren Avenue. Here’s the view from the west end over I-580.

And from the end of the cage section, you can see the east end, where it winds behind the Lakeview School and then over the freeway onramp.

If I ran this city, I’d refurbish this valuable bypass with an arched cage of clean chainlink that allows better views. And while I was at it I’d build another overcrossing on the other side of Grand Lake, connecting the severed parts of Wesley Avenue, because the climb up to MacArthur and down again is oppressive (though picturesque).

And why not? Because in the next hundred years we’ll be doing a lot of building and rebuilding. Taking this walk will force you to picture your great-grandchildren’s landscape in detail. And in my vision, unlike my fever dream, the lakeside streets are too important to abandon to the rising sea. They’ll be built up. We’ll still be able to walk around the lake along the shore, and we won’t have to take the route I mapped out.

However, the buildings along the shore are a different story. Here’s a little-appreciated geological fact: as the sea rises, so will the groundwater in the dry land along the coast. Basements that are a few feet above the water table today will be permanent pools in 2100. Streets laid down on dry ground will find their roadbeds turning mushy, more prone to traffic damage. In that respect, rising sea levels will affect things much farther from shore than the tides reach.

By 2100, today’s lakeside buildings will have gone through two or three more mortgage cycles — plus at least one damaging earthquake — and will be a century older. Given that, I think the apartment buildings on Lakeshore, for instance, will be dismantled by then and their lots condemned. And the road will move onto their old footprints.

The largest and most valuable structures will stay on — the Kaiser Center and its neighbor the Lake Merritt Plaza building, the cathedral, 1200 Lakeshore, St. Paul Tower, the Grand Lake Theatre and so on. Their owners will cope by reinforcing the basement levels and installing permanent sump pumps.

Buildings of lesser prestige, despite their historic value and charm, will face hard choices well before 2100.

The city will need policies in place to handle sea-level rise. But it’s possible that everything we do to cope can be done in an orderly way. That will require far-sighted city officials, and voters, to ensure sound long-term budgets and timely bond issues.

That will be a test.

On the other hand, a lot can change in a hundred years — just look back to 1918.

This post is dedicated to the people born this year, who will be 82 years old in 2100.

This entry was posted on 8 January 2018 at 8:02 am and is filed under Oakland geology walks, Oakland hazards. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.