Recovery Date: April 15, 2022
Total Marks Recovered: 11
Discs Recovered: 6
Non-Disc Type Recovered: 3 (Navigation Light [new], Pipe Cap)
Lost/Destroyed: 2
Note: Today's recoveries bring the total marks recorded in my database to 964!
A Day Off!
Short work weeks are always exhausting as you try to squeeze a full week's worth of work into four days, this week was doubly so simply because there was a TON of stuff going on in the office, but the reward was a well-deserved holiday, and a day off!
After spending the morning completing the required domestic and horse chores on my To-Do list, I opted to head south for an afternoon Survey MArk Scavenger Hunt, a.k.a. a "SMASH" (like how I did that?!šš¤£)
The game plan was to head to the Border Field State Park and hike around looking for survey marks that I'd previously researched and noted in my GAIA GPS App. I would pass through Coronado and head down the Strand, hopefully picking up a few marks along the way. From there I'd look for a handful of Tidal Benchmarks in Imperial Beach before heading to the Park.
As you might imagine, Coronado was crazy busy! It was an absolutely gorgeous day and when you couple that with the start of the long, holiday weekend, there were people everywhere! I passed on the "low hanging fruit" of recovering more of the survey marks that dot almost every street corner in the city proper (I still have more than 175 to document, see my previous article Coronado SMASH for more about that) and I patiently worked my way through traffic to get through town and onto the Strand.
Glorietta Bay - New Find: Navigational Lights!
As I approach 1,000 marks in my database, it still boggles my mind (and makes me quite happy!) when I find something new š Today's recoveries included a new Type of Survey Mark that I had not previously recorded in my database: 14 - Navigational Light. Prepping for this trip, I noted that both navigational lights by the Glorietta Bay Boat Launch were registered survey marks in the National Geodetic Survey (NGS) database!
The first mark, the Channel Range Rear Light is mounted at the edge of the sidewalk, near the seawall, and it was a snap to get pictures of it from the sidewalk as from below at the water's edge, providing the view boaters see as they return to the launch.
The second, Channel Range Front Light, is a couple of hundred feet out in the water and I had to settle for taking my pictures from a nearby floating dock. I probably do have pictures of this light somewhere in my photostream from previous kayak excursions. I've launched my kayak from this boat ramp a few times to paddle down to Crown Island and the Coronado Cays in San Diego Bay.
These "non-disc" survey marks can come in all shapes and sizes and are fun to recover.
Moving On...
Triangulation Station MAR (PID: DC1714)
A little further down the road, I had waypoints set to locate a few different stations, the first was MAR, a Triangulation Station set by the California Division of Highways. This one was almost TOO easy to find! The monument and witness sign was on a sand dune that formed a berm running along Silver Strand Boulevard, it also happened to be only a few feet from a California "C" post, and its witness stake. There was no missing the 16" cylindrical concrete monument for this mark, and it was refreshing to see that it was in perfect condition.
About a hundred yards further south, on the same berm were my next two targets: another Triangulation Station named SILVER STRAND and an interesting Pipe Cap marker named SOUTH PYLON 25 KM. I wasn't holding out much hope for the SILVER STRAND mark as I had read reports from 1955 that the monument had been destroyed and the disc was missing, the reference mark was also lost. However, being the eternal optimist, I had to look š No big surprise, it wasn't there.
SOUTH PYLON 25 KM (PID: DC1658)
Fortunately, recovering the SOUTH PYLON marker was a cinch, even without a witness stake to mark its location, it was "spot on" for the coordinates that I had saved in GAIA. This was noted as monumented (set) by the U.S. Navy, so this was my second "First" for the day, being the first USN marker that I've recovered.
NORTH PYLON 3 KM USN 1933 (PID: DC1693)
A bit over a half-mile further down the road was supposed to be the NORTH PYLON marker, however, when I reached the area where it was set, all I found was a square of concrete with the stub of a 2" pipe that had apparently been sheared off. Still technically a recovery, this one fell into the category of Lost and/or Destroyed.
Given that the concrete monument was sitting unevenly on the ground, this was probably disturbed (and the pipe sheared off) by some type of heavy construction equipment, and therefore worthless as a Geodetic Control Point. Sometimes, a disc can be lost (stolen) but the stem remains well mounted in the monument or bedrock, in those cases, the center point of the stem could likely be used as the place to take a measurement from.
Tidal Stations
Wrapping things up on the Strand, I headed into Imperial Beach with a list of Tidal Benchmarks that were oddly placed in urban areas. I've recovered many Tidal Benchmarks, finding them all generally within a stone's throw of the water. I was intrigued when I was researching these stations and saw most of them significantly inland. š¤·š»āāļø
The first few marks on my list were on School property (Mar Vista High School and Imperial Beach Charter School) two were set in PVC pipe sleeves and were near buildings, inside the school's fence line, so I passed on those. The third was in the concrete base where the flagpole was mounted at the main entrance to the high school. I checked it out, but the base had been resurfaced with small, smooth beach stones set in the concrete, there was no sign of the disc. This mark, 941 0120 TIDAL 7 was likely destroyed during the renovation of the pedestal where the flagpole is set.
941 0120 TIDAL 8 (PID: DC1335)
This mark was right where it was supposed to be, on the curb at Encina Avenue just inside the fenceline of Veteran's Park. Whoever set this mark didn't finish stamping the identification data on the mark, as it only says "TIDAL", but based on the coordinates and To Reach description from the datasheet, this is TIDAL 8 set in 1974. Based on the small section of curb that this mark is set on, it appears as if the sidewalk was added after the mark was originally set and they preserved the original section of curb that included the survey mark.
941 0120 TIDAL 9 (PID: DC1334)
I got super lucky with TIDAL 9, this one is actually located on the loading dock of the Imperial Beach Post Office on Donax Avenue (the loading dock faces Emory Street) I wasn't expecting the Post Office to be open, but as I arrived, a mail truck had just pulled up to the loading dock within a gated area. I flagged down the driver and asked if I could look for the survey mark, but even as I posed the question to him, I spotted the mark just a few feet from his truck! He didn't quite understand what I was doing, but I assured him I just needed a couple of photographs and I'd be on my way š
There were two Tidal stations located in the raised median of Palm Avenue, but after checking out their location, they would require pulling manhole covers and I didn't feel like making a trip back to the truck to get my tools. I'll save those for another time, preferably on a quiet traffic day.
One Park or Another
As I mentioned above, my initial plan was to head to the Border Field State Park and hike around the trails looking for marks, I had a few identified and was hoping to even recover a boundary monument or two (so far all my attempts at these have fallen short because they're on the other side of the border fence!)
I arrived at the parking area for the Park at 1645, the park technically closed at 1700 (5:00 pm). I had spent more time looking for marks on my way to the park, and I didn't leave myself enough time to search for the remaining marks on my list. Driving in on Monument Road, I remember passing a sign for the Tijuana River Valley Regional Park (and Campground) and wondered what I could find there.š¤
As I checked my map, there were trails and a potential station recovery within TRVRP, and it closed at sunset. I figured it was safe to leave the truck in the lot where I was parked since it wasn't gated, then I backtracked down the road to the trailhead that would take me up to the BAJA station.
The trailhead was across the street from the Campground which had these cool Yurts set up in addition to the varied RV and tent spots.
The hike up the hill was a simple road walk (closed to regular vehicles) to a network of dirt roads and trails at the top. I hadn't previously set a waypoint for the BAJA station, so once at the summit, I was able to check my NGS interactive map and pull up coordinates and the datasheet. Surprisingly, there were a lot of entries in the To Reach description area, I read through all of them in chronological order and began to develop an understanding of how the land at the summit changed over time.
The most current descriptions referenced a numbered telephone pole 519218 H (seen in the photos below) and provided directions to the station disc from there. As you can see in the photos, it's a wonder the telephone pole is still there as it isn't actively used for anything more than a very large witness post. Usually, when datasheets call out telephone poles with a number on them, the poles have long since been replaced and renumbered. I was amazed when I found this one!
Triangulation Station BAJA (PID: DC1632)
The datasheet identified the station disc as being 8.5 feet north of the telephone pole, the crude etching on the witness paddle nailed to the telephone pole confirmed that. I measured 8 feet to the north and started looking around, the best I could do was to locate a chunk of concrete at the base of the telephone pole that was probably from the monument. It had a smoothed impression where you could tell the concrete had been poured around a pipe, the pipe that the disc was very likely mounted to.
I searched around the telephone pole in all directions, also checking the directions to distance to find the reference marks, but came up empty-handed. I spent about 20 minutes looking around, before calling this one Lost and/or Destroyed.
When I got home, I found a Report of Survey (Map No. 7243) for the City Triangulation Network that covered portions of Otay Rancho, Rancho De La Nacion, City of San Diego, City of Imperial Beach, City of Chula Vista, County of San Diego and the State of California. The ROS provided verified coordinates of 57 stations; BAJA was used as one of two stations that all bearings were based on for that survey. The coordinates were all provided as State Plane Coordinates (SPC) based on the North American Datum of 1927 (NAD27), I used the NGS conversion tool to translate those to latitude and longitude, and confirmed that I was at the right spot for the BAJA Station.
I bought a copy of the ROS from the San Diego County Surveyor's online research system, I imagine most of the 57 marks listed in that survey are long since gone, but I'll convert the coordinates, plot them on my map, check them against current development (using Google Earth) and see if I can't make a few recoveries from all the data. It is pretty funny that several of the stations listed are named after Disney characters: Donald, Dumbo, Figaro, Horace, Mickey, and Minnie! I highly doubt that any of those stations still exist, but I'll look for them anyway.
One More Park: Montgomery Waller Community Park
SAN DIEGO GPS 24 (PID: DC2134)
My final recovery for the day was an SDGPS station located in Montgomery Waller Community Park, from my research, this was going to be an easy recovery as the two reference marks were mounted on the curb along the east side of the parking lot and the station disc was in a PVC sleeve a few inches below ground.
It just so happened that I parked right next to RM 2, spotting it as I pulled into the parking lot. After making that quick recovery, I walked down the sidewalk with my eye on the curb, quickly finding RM 1. On traditional reference marks, there is usually an arrow that points toward the station, as you can see from the images of these marks, they didn't have that.
Knowing that the station was in a PVC sleeve, I started scanning the area for the tell-tale cap with the square nut on the top (I did have my pipe wrench in the truck). I crisscrossed the area where the mark should have been but didn't see any PVC pipe or cap. I double-checked the datasheet and my coordinates then started kicking around in the wood chips near a slight depression. Success! I uncovered the top edge of the PVC pipe and then grabbed my pack shovel to clear the rest of the area to make the recovery.
I've said this more than once, I really need to buy a handful of the screw-on caps for 6" PVC pipe and just keep them in the truck, that way I could replace these when I find them missing or broken.
Wrapping Up
All-in-all it was a pretty successful afternoon, I made 11 recoveries that include a couple of "Firsts" and brought my total survey mark count in my database to 964. I will definitely be headed back to Border Field State Park and the surrounding area to search for more marks, it'll take some time to convert all the SPC data for the stations listed on ROS 7243, then plot them on my map, but I'll get there. š
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