California Surveyors Forums

I’m curious.

Based in the Elon Musk TED Talk about his hyper loop, I have a question for the collective.

https://www.ted.com/talks/elon_musk_the ... and_boring

Above a certain altitude, airplanes are allowed to pass over my house, even though I own the land from the center of the earth to infinity.

Is there an elevation below ground for tunnels?

How are the tunnels in Los Angeles regulated? Do they have easements for the tunnels? How are they set up?

Obviously, the tunnels are mapped. How are the tunnels rights protected? For example, in the Bay Area, piles are driven to bedrock (or not in some famous tilting cases). How do we protect the tunnels from driving piles through the shaft?

My first thoughts are that the tunnels for the trains under Los Angeles must have brought these issues to light. I wonder how they have been dealt with there.

Anyone?

Just recently (within the last year or two), I worked on a tunnel project through LA for an outfall sewer. Where the tunnel is within private property, the County was acquiring subsurface easements for the tunnel. In some areas the tunnel will be 100' plus below ground. Other area, 30 - 60 feet.

Since an airplane is transitory, occupying the airspace that someone on the ground theoretically owns for a few seconds or less (a very small fraction of a second for most parcels projected to 48,000 feet or so), having no permanent facility in place to accommodate its passage through any particular airspace, and a tunnel is a stationary facility that remains in place once built to accommodate the occasional or regular passage of some vehicle(s), I don't think that you're going to be able to find any parallels that would allow you to forego the need for easements and entry agreements with the several hundred or thousands of landowners that the tunnel would pass beneath.

I would think that depth will depend more upon the physical geology than most other factors, but the existence of privately owned or leased mineral rights will probably factor in here and there as well.

I think that a continuous series of surface easements wouldn't be required except to the extent that they be available in the event of emergency repairs where the best, most feasible, or only access point to the location needing repair is from a nearby surface location. Regardless, I can see some surface easements at various locations along the route being needed to accommodate regular maintenance access points.

I would think that a continuous easement defined by horizontal location and depth range would be required. The real question being who needs to grant that easement or license. A basic tenet of land law is that the titles to all lands are vested in someone or in some entity (Civil Code §669). There is no such thing as un-owned land within the borders of the State. Where title in some other person or entity can be found to any portion of land, it is presumed to be owned by the State (CC §670).

Where the base title to the surface lands was granted with no mineral rights reserved, and no intermediate fee owners through the chain reserved the rights, both surface and underground easements would need to be granted by the surface owner (or condemned as such). For those surface lands for which the mineral rights were reserved, the owner of those rights may have to grant the easement. Many lands that have their base title in a State patent were granted with the State having reserved any mineral rights. Best check with someone in the Mineral Resources Management Division or the Legal Division of State Lands to see how much of a concern that is and if there is any application & review process involved.

Where there is expected to be no surface impact from construction or normal operation of the tunnel, I don't know what the depth would be that would be considered the separation of surface title and underground, or mineral rights title. Civil Code §659 is the one that talks about ownership of land being "an indefinite distance upwards as well as downwards", but also qualifies that by adding "subject to limitations upon the use of airspace imposed, and rights in the use of airspace granted, by law." It may vary depending upon the type of mineral rights reserved and perhaps on the local geology. There may even be a range of depth where it is considered to be within the title ownership/interest of both the surface owner and the mineral rights owner. Given that there is no qualification stated as to depth similar to the qualification for airspace in CC §659, it would appear that the surface owner would be the owner, subject to any reservations for mineral rights, for an indefinite depth.

I know that my counterpart in LA at the time tied their tunnel easements for Caltrans to a robust, dense, vertical datum instead of a depth from the surface, which could change over time.

This is what I wanted to happen on the easements for the new Caldecot tunnel bore but the RWE working on the project followed the example of the 'oldtimers' and wrote it as a depth.

Tying and describing with reference to a datum makes good sense for many reasons. Describing by depth has only one really good reason that I can think of, and that being that it is what the landowner would find most understandable relative to what they know of their parcel.

That one reason is enough to warrant a described depth relative to the surface while the many good reasons to describe by elevation relative to a known datum warrant that approach.

No reason that the descriptions can't contain both and written such that the datum relationship is controlling and depth call informational.

In order to know the depth elevations on the surface and from the construction plans have to be known.

Also, many roadway tunnels have vertical curves. So, if a depth is used as a call or for informational purposes then a range should be included because the depth changes.

I recommend including the VC info tied to a vertical datum and a horizontal datum. That way a property owner with the aid of a surveyor would the actual depth at any point on their property.

The aforementioned subsurface tunnel easements I worked on were based on NAVD88 elevations and specific benchmarks for each location. The vertical limits were elevations rather than depths measured from the surface.

Not to mention if the property surface is hilly.

One must determine the owners of both the surface and subsurface for tunnel easements and acquire rights from both if the subsurface rights have been severed from the surface owner. The description of the easement is typically tied horizontally to surface monuments of record and vertically to elevations with datum referenced. Typically the description is in either a rectangular or circular shape using the spring line or invert as the control line. The depth at which surface rights may be required is dependent upon the geological conditions and in my experience based on recommendations of the geologist.

Wouldn't it fall under the part of your deed that limits subsurface rights?
Unless you happened to inherit grandpas orange grove properties have relinquished subsurface rights below a certain depth.

There is an old petroleum pipeline in Corona north of the 91 that was put in X feet below the surface. When it was put in it was just low rolling hills now development has come along and flattened out the land and sometimes plans have to be adjusted because the new grade doesn't give the pipe enough cover.