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Sutro Forest 2017 Plan Imposes a Landslide Risk

August 29, 2017

This article is reprinted from SaveSutro.com with permission. The landslide hazard described touches our neighborhood; Christopher Drive and Crestmont are both in Forest Knolls!

This is risk that may actually increase over the years as a result of actions being taken now, for two reasons.

  • First, tree roots take time to die and rot, but when they do, they weaken the living geotextile that stabilizes the hillside.
  • Second, trees take up water and help to regulate moisture deep in the ground. When large trees are cut down and stop doing this, small saplings and ground cover are not an effective substitute. So if the trees are cut in dry or normal years, nothing may happen for a while – and then a really wet year can trigger landslides that would not have happened if the trees had remained.

Landslide under blue tarp. South Ridge at top left.

We’re reading the Draft Environmental Impact Report (DEIR) for the 2017 Sutro Forest Plan, and got to the section on landslide risk. This has been one of our concerns, especially since the tragedy at Oso, Washington, where the felling of trees in previous years was a factor in destabilizing the slope. (We wrote about that HERE: Cut Trees, Add Landslide Risk) We know this area is subject to landslides – we had a blue tarp covering unstable areas in Forest Knolls for a year when cutting trees destabilized a slope, and another just above UCSF’s Aldea housing area.

SHOCKING LANDSLIDE INFORMATION

We were shocked at what we found in the DEIR:
“Increased instability could cause a landslide that would impact Crestmont Drive, Christopher Drive, and Johnstone Drive. An existing landslide scarp is visible above Christopher Drive. Some homes along Christopher Drive could be placed at additional risk from localized landslides due to plan implementation. Phase I activities would result in a potentially significant impact…”

The map above is taken from the DEIR. All the dark green areas are potentially unstable. All the gold areas are potentially unstable. All the cream areas are potentially unstable. The little red blobs and stars are already unstable. The black arrows show the direction of potential landslides – right into our communities. Here’s the key to the map. The light yellow and light green areas are where they are cutting down trees in Phase I (five years, starting this fall – 2017):

Legend to Landslide Hazard Map Sutro Forest 2017

What’s the proposed “mitigation”? Avoiding work in the forest for 2 days when the soil is wet after rain. This completely ignores the fact that landslides are a MULTI-YEAR hazard after tree removal.

Here’s the proposed mitigation in their own words:
“After a significant storm event (defined as 0.5 inches of rain within a 48-hour or greater period), the following conditions shall be met prior to any vegetation management activities:

  • The maps detailing areas of historic slope instability or rock fall in the Final Geotechnical and Geological Evaluation Report for UCSF Mount Sutro shall be reviewed (Rutherford + Chekene 2013) 
  • If ground-disturbing or vegetation removal activities are proposed within or adjacent to areas of historic slope instability or rock fall, the saturation of the soils shall be estimated in the field; if muddy water drips from a handful of soil, the soil is considered saturated (Brouwer, Goffeau and Heibloem 1985) 
  • The areas of historic slope instability or rock fall shall be flagged if the moisture content of the soils is determined to be high (i.e., muddy) and ground-disturbing or vegetation removal activities shall be avoided for a minimum of 48-hours after a significant storm event to permit soil drying…”

In other words, we won’t chop down trees in the rain or when the soil is wet.

Other mitigations are palliative. They’re planning to build roads into the forest for trucks and heavy equipment, and those roads will follow the contour of the slope. The quarter-acre staging plazas – where they’ll remove trees so trucks can turn around and heavy equipment be parked – will be flattish, with a slight slope for drainage. None of this is as effective as not building these roads or bringing in heavy equipment in the first place.

WHY THE MITIGATION IS MEANINGLESS

The problem is, the effect of cutting down trees is a LONG TERM problem. The effect of tree removal takes years – not days, not months – to fix. In Oso, Washington, the slope gave way three years after the last tree-destruction. Here’s the story (from the article we published at the time). The tragedy was foreseen… but the regulators thought they had enough mitigations in place.

On March 22, 2014, a huge landslide destroyed the small Washington community of Oso. Rain was of course a factor, as was erosion at the base of the slope. But it’s probable that tree-cutting above the slide area was an important factor too. An article in the Seattle Times that quotes a report from Lee Benda, a University of Washington geologist. It said tree removal could increase soil water “on the order of 20 to 35 percent” — and that the impact could last 16-27 years, until new trees matured. Benda looked at past slides on the hill and found they occurred within five to 10 years of harvests [i.e. felling trees for timber].

There had been red flags before. The area was second growth forest, grown back from logging in the 1920s/30s. Over 300 acres were again logged in the late 1980s.

The first time regulators tried to stop logging on the hill was in 1988. But the owner of the timber successfully argued that measures could be taken to mitigate the risk. Eventually, the state only blocked it from logging some 48 acres, and the owners  gave in on that.

In 2004, new owners applied to cut 15 acres; when the Department of Natural Resources (DNR) objected, they halved the area and re-located the cut. DNR gave approval, subject to no work during heavy rain and for a day afterward. The tree-cutting finished in August 2005.

In January 2006, there was a major landslide 600 feet from the cut zone. The state built a log wall to shore up the slope.

The owners continued logging. In 2009, they removed 20% of the trees. In 2011, they removed another 15%. In 2014, the hillside collapsed.

The regulators were aware of the risk; they thought they were mitigating it with their restrictions and reaching a compromise with the owners. But it wasn’t enough. Destabilizing the mountainside is a long-term thing; the effects can show up in months, but it’s more likely to take years.

THE LESSON FOR MOUNT SUTRO

Our mountains not only are potentially unstable, they actually have landslides. The picture at the end of this article shows one on Twin Peaks, where rocks tumble after nearly every heavy rainy season.

The roots of the trees are helping to hold the unstable soil in place and that as the roots rot, landslide risk will increase.  It is going to be more unstable 2-3 years after the trees are removed than 2 days after it rains.  The information that instability increases over time is a little counter-intuitive.

Moreover, removing the trees takes away their ability to suck water out of the soil. If the tree-cutting is done in dry years, it may take a wet winter to trigger landslides… which would not have happened if the trees had been regulating the water and functioning as a living geotextile.

Since UCSF are not going to use herbicides on the stumps to prevent them from resprouting, they say they will grind the stumps.  That is an effective way to prevent resprouting, but it will greatly increase the instability of the soil because the heavy equipment digs down several feet into the stump to destroy the roots.  That’s another reason why they should not destroy trees where slide risk has been identified.

Anyone seriously considering the map above can only hope that UCSF will draw a better conclusion than the Washington State loggers and regulators. The planned destruction of thousands of trees – many within the first five years – could cause landslides in surrounding communities not days or months later, but years after the event.

UCSF: First, do no harm!

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Easter Egg Hunt on Sunday April 16th – Inner Sunset

April 11, 2017

Here’s an announcement from Barbara Oleksiw, who organizes great neighborhood events in the Inner Sunset. (Thanks, Barbara!):

Sunday, April 16, 2017 – 10a.m.to Noon
NW Corner of 6th & Irving, Inner Sunset,
ALL Welcome to the **FREE** Easter Egg Hunt, in the Inner Sunset.
Rain or Shine, 10 a.m. to Noon.

Hundreds and hundreds of hidden eggs waiting to be found.

Bring your basket, or use one of ours!

No age too young.

Our Forest Knolls Coyotes

March 26, 2017

We’ve known for years that coyotes are all around us in Forest Knolls – I wrote about it here when a couple of neighbors reported seeing them. (LINK: Coyotes Among Us)

But this time, neighbor Michelle Lukban got this really neat picture (published here with permission). For everyone who’s been jealous of Bernal Heights coyote pictures, we got ours! [Edited 3/27/17 to correct attribution of picture]

 

BEING CAREFUL AROUND COYOTES

Janet Kessler,  the Jane Goodall of SF’s coyotes, has for many years been observing, photographing, and reporting on our San Francisco coyotes. Her website is at CoyoteYipps.com. She’s also involved with Coyote Coexistence, an organization that helps people and coyotes to co-exist safely.

For guidelines on staying safe – and keeping pets safe – around coyotes, click on this LINK:  Coyote Coexistence Guidelines

And here’s a 30-minute video on the subject.

Coyotes are not very concerned about people, and are generally quite shy of them. But they are very interested in dogs. Coyotes are territorial animals, and dogs could be considered interlopers. Also, some dogs chase coyotes, and so coyotes may feel threatened.  Often the coyote will remember which dog it was. Don’t let your dog do this. It could be dangerous for both animals. Finally, really small dogs – and cats – may be viewed as prey. This is rare, but it has happened. If you have pets, the video above may be useful.

Coyote looking at a dog (2011)

“San Francisco Overlook” Project for Sale

January 24, 2017

We’ve been following the much-disputed San Francisco Overlook project for some years now.

 

Crestmont map

This is the planned development at the end of narrow, twisting, Crestmont Drive and was earlier called the Crestmont Hills project.

San Francisco’s Planning Commission approved it in 2013, and we reported on that HERE. Soon afterward, the developers reached an agreement with the Mt Sutro Woods Home Owners’  Association to reduce the number of units from 34 to 29, and reduce the heights of the buildings. An April 2015 report on the real estate website, SocketSite.com, reported that the project was able to proceed.

But it didn’t proceed. Instead, it was put up for sale.

sf-overlook-crestmont-location

SF Overlook Project on a very steep slope – Google Maps image

FOR SALE AT $14 MILLION

  • In May 2015 SocketSite reported that the site was for sale, with the plans for the units (but without building permits).
  • In January 2016 they reported that the asking price, initially $20 million, had been cut to $15 million.
  • And in November 2016, they said the price had been cut to $14 million.

Hmm. According to a November 2016 mailing I received from realtor John Kirkpatrick, homes in the Forest Knolls neighborhood sold for an average of $1.195 million. Forest Knolls homes have 2 or 3 bedrooms and 1 or 2 bathrooms, but the back half of the garage typically offers customizable space. You can put in another 2 rooms and bathroom down there if you want. They’re standalone homes with no shared walls and most of them have a yard. That’s the competition to this project.

Let’s say these 29 luxury homes are priced at about $1.5 million, because they’ll have the latest fit and finish. Other benefits, like a 2-car garage and views are not unique to the development.

That would be a gross take of $43.5 mn, roughly 3 times the asking cost of the land and plans. Is it worth it? I don’t know.

ACCESS IS STILL AN ISSUE

Though there’s an agreement with the Mt Sutro Woods HOA, the project’s  only access runs through the very narrow Crestmont Drive, which has houses on one side and a steep hillside on the other. Though on the map it looks like you could easily link it up to 5th Avenue, the intervening land doesn’t belong to the developer and is also very steep.

The way in to these 29 would-be homes is through the Forest Knolls neighborhood. Fears of destabilizing the mountainside where many homes are supported by concrete piers, fears of added traffic on an already narrow street, fears of potential emergency situations with very poor access, all could fuel more opposition.

The steep hillside above the planned development

The steep hillside above the planned development

Forest Knolls Holiday Party – Dec 18, 2016

November 26, 2016

christmas-treeWalter Caplan of the Forest Knolls Neighborhood Organization asked me to post this “save the date” for the Forest Knolls Holiday Party. It’ll be at the Armenian Church at 275 Olympia Way, on Dec 18 at 4 p.m. – with snacks, dinner, Santa, and gifts for children.

Unlike previous years, there’ll be a $10 per adult charge to cover costs. Children are free! If you wish to attend, please fill in the form below (or still better, in the linked PDF file) and mail it in with your check.

(Download the PDF here: forest-knolls-christmas-2016-save-the-date2a )

fk-party-dec-18-2016-1

fk-party-dec-18-2016-2

Halloween Loop in Forest Knolls – 2016

October 25, 2016

pumpkin clipart public domainIt’s that time of the year again! You may have seen the orange flyer in your mailbox or on the fence at the entrance to Forest Knolls: “Forest Knolls Trick or Treat Monday October 31”

Each year, the Forest Knolls Neighborhood Organization (FKNO) encourages neighbors on Oak Park and Warren Drive (and a small stretch of Christopher) to join the “Loop” – a Halloween-friendly route that kids can trick-or-treat on.

This year, it’s been expanded to Forest Knolls Drive and Woodhaven Court. It runs between 5.30 and 8 p.m. People who want to greet kids with candy can get a pumpkin and a pumpkin sign to let them know they’re in. FKNO will provide both pumpkin and sign – email Walter Caplan at whcaplan@comcast.net

halloween-2016-1Here’s the map. If anyone wants to send me pictures afterward (and maybe a few lines about the event?) I’d be happy to publish them.

halloween-2016-2

Humpback Whales in Pacifica

August 14, 2016

One of the delights of living where we do is being so close to wildlife. I don’t mean just the raccoons or the hawks – but actual whales! I’d been seeing Youtube video of humpback whales in Pacifica, barely 15 minutes south of us.

whale spout_4867

So I went out to Pacifica Pier around 4 p.m. on a sunny Saturday afternoon,  hoping that I’d maybe see a whale. I was disappointed to find access is truncated – the pier is shaped like a shallow L, but the short arm was closed off after a big storm damaged the parapet. (In the picture below, you can see the concrete slab of the wall has been pushed in by the waves. I wish they’d repair it!)

damaged pier 4784

In the fine weather, the Pier was crowded.  Lots of people were fishing, lots of others walking around. My hopes rose when I saw a couple of people armed with cameras with lenses as long as my forearm… maybe they were seeing whales? I only had my iPhone camera, but thought maybe I’d get some distant sightings.

I didn’t have to wait long. Almost immediately, I could see the puffs of whale-spouts in the distance, north of the pier.

whale spout of Pacifica Pier 4782

Humpback whale spout off Pacifica Pier

Soon I could even see the whales when they surfaced. Flocks of birds surrounded them. As they fed, the fish that escaped them fed the gulls and other sea-birds. After I’d been there an hour or so, I wanted to leave. Except, I couldn’t. Every time I started to leave, more whales swam by.

fishing poles and whale spouts Pacifica CA 4819

Finally, one came in so close, it was inside the surf line. Someone next to me was explaining to a friend that it was likely a calf, and the shallow water was easier to breathe in. It was almost alongside the pier. After a minute or two, it turned around and swam back out.

humpback whale pacifica 4846