Over time I’ve come time and again to the quiet, however as soon as eventful Reservoir Hills neighborhood, on the Glenview facet of Sausal Creek and south of I-580. This weekend I led a stroll for the Buddies of Sausal Creek via the world, which gave me the possibility to dig slightly deeper, therefore this publish.
This compact neighborhood accommodates two options of geological curiosity: Central Reservoir and the McKillop Street landslide, formally disguised as William D. Wooden Park. The reservoir occupies slightly stream valley that feeds Sausal Creek, and the landslide has been undermining the excessive financial institution of Sausal Creek proper subsequent to it. Each are older than they appear, and each are altering.
The reservoir started first, so far as I can inform. The Contra Costa Water Firm, within the Eighteen Eighties, set their sights on this valley as a result of it was properly located for a secondary reservoir. On the time the corporate’s water was horrible stuff, inexperienced and smelly, and so they needed to make a “settling reservoir” there to carry water from Lake Chabot and Sausal Creek till it clarified a bit. The land, a few of which had been a part of the property of Capt. Levi Stevens, turned obtainable after his demise in 1882, and the water firm started to dig a big basin however then stopped work for a few years. A few of the grime, the corporate’s chief engineer later testified, “was used to fill some tons close by.”
Work resumed in 1909 after the Peoples Water Firm acquired the property, and the reservoir entered service in 1910. At the moment, metropolis engineers had observed some landsliding to the east, on the slope overlooking Sausal Creek throughout the low ridge between the 2 areas. That ridge was subdivided and developed within the late Nineteen Twenties, and the residents of the brand new streets, Sheffield Avenue and McKillop Street, loved considered one of Oakland’s most interesting views.
Repeated landslides started to have an effect on the slope, beginning in 1935 and lasting into the Fifties. Every time a number of extra homes on McKillop Street had been destroyed, residents demanded motion, and town sponsored research. Lastly within the Nineteen Seventies sufficient cash was assembled to accumulate the ruined land and sculpt it right into a easy park with a degree subject and an engineered slope that’s held up properly because the park was devoted in 1976. The central half of McKillop Street was erased, however each ends stay.
Thirty years later, the landsliding resumed, this time on the downstream finish of the sooner failure. The 2006 slide took out one other home and left a multitude that town hasn’t touched since then.
At this time you possibly can’t see this as a result of it’s all overgrown. The close to a part of the property, owned by town, is used at the moment by a small plant nursery, Wildheart Gardens. After I was there this weekend, I used to be advised that the slope remains to be giving approach.
At this level it will likely be useful to look intently on the floor, as revealed by lidar surveys and the ensuing digital elevation mannequin which ignores the timber and buildings to indicate the underlying land floor.
Derived from nationalmap.gov; north is to the suitable and illumination is from the higher proper.
It reveals the clear traces of Wooden Park and the jumbled ruins of the 2006 slide to its left. Two homes stay on the east facet of McKillop, between the 2 slides; they had been red-tagged in 2006 however not condemned.
In any disaster, individuals will attempt to determine the way it occurred and, if legally attainable, who accountable. The Central Reservoir was at all times a suspect, however I believe a geologist will let you know that this was unlikely. In any case, the lawsuits that adopted the 2006 slide had been rejected by the jury. If I had been licensed to observe geology in California, I might have predicted that.
Many causes are attainable, and so they can overlap. The world the place the slides started was a part of Capt. Stevens’ property, and he was an important lover of unique crops who tapped the creek to water them, and he in all probability moved some grime round. The creek is of course eroding its banks and undermining the hills that line its floodplain. The reservoir did and does leak to some extent via its concrete and asphalt lining. The Eighteen Eighties excavation spoils may have been dumped alongside the highest of the ridge the place McKillop Street would later run, creating weak floor and loading the slope. Houses constructed on hillsides add their weight―and their house owners’ watering habits―to the slope. Poorly designed roads have related results. And landslides develop all by themselves as a result of their edges are unstable scarps.
Given a selection amongst these prospects, I’m inclined to say “all the above” and go away it at that.
The reservoir, by the best way, shall be changed throughout the subsequent decade. The location shall be occupied by three giant metal tanks, and the entire water system will work a lot better. In regards to the slide space . . . we’ll see.
