Return to Volcan Benchmark
Updated: Mar 11
Date: March 9, 2021
Distance: 6.46 miles
Total Elapsed Time: 3h 18m *
Total Moving Time: 2h 44m
Summit Elevation: 5,330 feet
Elevation Gain: 1,249 feet
Trailhead: Farmer's Road
February 8, 2020
August 9, 2020
January 4, 2021
The exact same Total Elapsed Time as my January 4, 2021 Trip!
New Survey Markers today - 1 Recovered, 1 Confirmed Lost/Destroyed
This morning I made my fourth trip back to the Volcan Mountain Wilderness Preserve to hike up to Volcan Benchmark, I REALLY needed to get this done today because we have a winter storm scheduled to hit tomorrow that is supposed to dump snow on elevations as low as 3,000 feet. When I did this hike in January, I was stymied in my search for the USGS Volcan Station disc primarily due to snow on the ground.
As I got my gear together, I cursed myself for not doing this yesterday, it was a beautiful day, this morning it was already starting to get windy and it was very cold. On the plus side of today's weather and the upcoming storm, there was only one car at the trailhead when I arrived. Another vehicle drove up while I was getting ready and two women started out on the trail slightly ahead of me.
I hadn't even made it to the Gateway when the two women were headed back towards their car. Jokingly, I asked, "what'd you forget?" They replied "Nothing, we just weren't prepared for this wind and cold! We're going into town and get some pie!" 🤣 I snapped this picture of the Gateway mere seconds before the lone hiker on the mountain came around the corner to head back to her car. She gave me a heads up that it was cold, windy, and foggy at the summit. I had anticipated the weather and was appropriately layered up. I took periodic weather readings throughout the day and the temperature hung right around 39º and winds averaged about 22 mph, however, I did measure maximum winds at the summit of 44.9 mph which was a wind chill of 25.3º 💨Brrr...️
My sole mission today was to look for three survey marks that I hadn't previously found for this station, the Azimuth Mark, the SDGPS Station 14 disc, and the USGS Volcan Triangulation Station.
Volcan Azmuth Mark
On my January hike, I had previewed the NGS datasheet, read over the descriptions of where the marks were located and felt comfortable that I'd be able to find them. I missed one critical direction in locating the Azimuth on my January trip and I ended up thoroughly searching the wrong area! Of course, I didn't bring a printed copy of the datasheet with me (now standard operating procedure!)
Today, not only did I have the printed copy of the datasheet, but last night I plotted the points for the Azimuth based on the calculated location of the Station disc. Since I hadn't located the station disc, this could be off a little, but it would put me in the general area. I checked and re-checked the bearings, and broke down each piece of the written directions to ensure I was going to be looking in the right place.
The description mentioned a white witness post near the mark, but that was obviously long since gone. I was looking for a boulder about 18" above the ground that was the west-most rock in a grouping of rocks on a small knoll. I searched every rock pile within a 200-yard radius of my anticipated location and came up empty.
Unlike other Reference Objects, Azimuth Marks are listed on the datasheet with only an azimuth reading from the primary station - they don't give a specific distance. Sometimes the station recovery description will give an approximate distance, but you just never know how accurate that is going to be. I picked up the bearing about a quarter-mile from the summit and simply walked the heading checking all rock outcroppings I passed. Nada.
I'm going to mark this one as "Unable to Locate" because while I clearly didn't find the disc, I didn't find any evidence of its placement either, there was no telltale 'hole in the rock' that would make me believe it had been lost/destroyed. I figure one of two situations could exist, it's either buried or it is further from the station than the recovery notes allude to.
The Big Picture at the Summit
Having spent a good chunk of time wandering around looking for the Azimuth Marker, I was ready for an easy 'Win'. I headed up to the summit to look for the next mark on my list.
This image is the big picture view of the survey marks I've located at the summit (green "√") and the confirmed lost/destroyed (red "X"). I struggled with posting this as it makes it ridiculously easy for anyone to find all the marks that I did without having to go to the trouble of reading/deciphering the datasheets, stumbling around searching every boulder or rock outcropping, or crashing through the weeds and poison oak. But, it's illustrative of the process I go through ahead of time to plot what I know (from previous recoveries) and to use the data I've researched to give a best-guess of where my targets are located.
Hint: I have the location services turned on for my camera so when I take a picture of a particular mark, it records the latitude and longitude of the picture (that's why I take pictures directly above the marks). Sure, it's never going to be as accurate as legit surveying equipment designed only for that purpose, but it works well enough for my designs.
San Diego GPS Station 14
My easy find for the day was the SDGPS-14 Station disc. I had located the two reference marks back in January and I thought they were pretty cool, but at the time, I knew nothing about these marks beforehand as they were the first markers in the California High Precision Geodetic Network that'd I'd found. When I was going over my map last night, I figured finding the station disc was going to be a no-brainer...and it was.
What is really funny (to me at least), I walked right past the boulder where this station disc was mounted and never saw it! The only thing I can think of is that it must've had snow on it covering the mark. 🤷🏻♂️Anyway, I closed that triangle with the station disk.
This particular station is a perfect example of the use and placement of reference markers, one of the key requirements of setting a reference mark is that it must provide an unobstructed view of the station that it refers to. If you recall from posts I've made about marks on Woodson and Cuyamaca, new reference marks had to be set when the construction of various objects interfered with sightlines back to the station (the concrete cistern and lookout tower leg, respectively). Of course, this station-reference mark relationship is very obvious in the 'big picture' image above. Lesson Learned: Whenever I locate two reference marks on ANY trip, you can damn sure bet I am going to be looking hard for a station disk at the apex of a triangle.
USGS Volcan Benchmark Triangulation Station
Having picked up the easy find with the SDGPS-14 Station, I headed up into the trees to Volcan RM 2. I'd found RM 1 and 2 back in January and had taken my pictures of them back then, I decided to try my liquid chalk method on RM 2 to get a better picture, it came out really well. I was going to do the same with RM 1, but honestly, my fingers were numb preparing this one!
The process is, I squeeze a little liquid chalk on the disc, then rub it in to fill all the stamped/engraved lettering, then wipe the excess off with a rag. Well, with 25º windchills and a brass disc mounted in rock, that thing was COLD! 🥶I figured one was good for proof of concept, my main mission was to find the Station disc.
I had forgotten to bring my tape measure 🤦🏻♂️which would have made the process SO much easier, but I knew the distance between RM 2 and the Station was 3.225 meters on a 220º30' azimuth...and the arrow on the reference mark pointed the way. I took out a length of paracord, tied one end to a rock, and set it on the RM 2 disk then I walked about 4 paces in the direction of the arrow and anchored the paracord on the ground with another rock. It crossed right over this rock with a hole in it!
Upon closer inspection, you can see the remaining bits of concrete that had held the disk in place and the perfect hole where the stem was inserted. Good news, I'd found the location of the Station, bad news the disc was long gone. Thinking back to January, this rock was clearly covered in snow, and while my same trick would have worked, I would have had to dig out the snow to confirm it.
Lesson Learned: Add my tape measure to my "survey mark locator kit" that stays in my backpack. Or I may just take a length of neon paracord and add 1-meter marks to it using a sharpie, it'll definitely pack lighter than a tape measure and will be accurate enough for what I need.
Relive® 3D Video of Toady's Trip
This Relive video is not that much different from all my prior trips with the exception that you can follow my wanderings as I looked for the Azimuth Mark. I ended up with a little more mileage than I usually get just going to the summit, but I was really surprised to see that my Total Elapsed Time from today's trip was EXACTLY the same as my trip in January (and I covered more ground today!)