Field Notes

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Gilbert Tract: 2021-09-09 08:20:00 (DOY 252)
Author: Daphne Szutu
Others: Joe

Summary: Work trip to tie up loose ends from the site setup, solar panels were not plugged in so only 3 days of data--fixed, installed water and soil sensors, improved and added tower tiedowns, met others working at Dutch Slough, lots of ants, hot and muggy

2021-09-09
Gilbert Tract

Joe and I arrived around 8:20 PDT for a maintenance trip. It was sunny, warm, and muggy. There was a little breeze at the top of the tower and some slight cloud cover in the afternoon; both made the mugginess more bearable. We could see and hear at least a few tractors working on the Emerson parcel next to the slough.

Many ants were using our sensor cables as little highways to get from place to place--there were ants in the datalogogger box despite the half-melted mothballs still present. I left more mothballs in the datalogger box, the CR10x box (which had some wasps), and the 7550 box. I sealed the CR10x but left the datalogger box open for now so the ants can escape the mothballs.

We had a lot of visitors over the day. Scott came by around 11:00 to pick up his 2â€™ extender bar we forgot to return last time. He was testing out some 2.5m tall chambers over the wetland plants. Two biologists, Isabel and Claire from River Partners, also stopped to see what we were up to. Isabel is the lead biologist on the native plant revegetation and they have ongoing vegetation monitoring for at least a year I think, and they hope DWR can fund them for further surveys. They mentioned some of the tules were planted by placing tule root balls in holes dug by a mini excavator, but the cattails were all volunteers. They also have someone at the site 5 days a week to do weed control. Later in the afternoon, Katie B drove by to say hi and we told her about the shotgun sounds from last week.

When we arrived, there was no power to the tower because we had forgotten to plug in the solar panels last week, so it ran for 3 days off of the batteries before the batteries drained down too low. The charge controller did not have "Low Voltage Disconnect" set, so the batteries had been drained lower than usual. Joe plugged the solar panels in. Before we left for the day, we disconnected the panels briefly to see how the batteries would hold their voltage. They still read ~24V, which is good, but weâ€™ll have to keep an eye on battery health.

Joe added security nuts on the solar controlled box U-bolts. There are some holes in the box that need to be covered with mesh to keep insects out.

We moved up the data logger box up and to the left to add slack to the radiometer cable runs. The 2â€ bolts were just the right length to hold the box to the 2x4.

Joe put on waders and got in the water. He first used the auger to dig a well pipe about 4-5m west of the tower. He observed that the top 2cm of the soil was a soft gravel/sand that he could dig his fingers into. Below that was about 30-40cm of hard gravel/sand that was extremely hard and annoying to dig through with the auger. Below the hard gravel/sand was more clay-ey. He installed water level sensor sn 20010026 in the well.

Distance from top of well to sensor: 130cm
Distance from top of well to ground: 60cm
Distance from water level to ground: 26cm

Joe installed our revamped thermocouple profiles that are covered with plastic split loom instead of metal conduit. (+) depths are above the soil and (-) depths are below the soil.

TC set A: +45cm, +30cm, +15cm, +5cm, 0cm, -2cm, -8cm, -16cm, -32cm
Set A is southwest of the tower on a ~10m cable length. It is in a location where the water column is 45cm deep, so the top thermocouple is right below the water surface (today).

TC set B: +30cm, +15cm, +5cm, 0cm, -2cm, -8cm, -16cm, -32cm
Set B is northwest of the tower on a ~10m cable length. It is in a location where the water column is 30-32cm deep, so the top thermocouple is right below the water surface (today).

TC set C: +15cm, +10cm, +5cm, 0cm, -2cm, -8cm, -16cm, -32cm
Set C is west of the tower on a ~5m cable length. It is in a location where the water column is 18cm deep, so the top thermocouple is a few cm below the water surface (today). Set C originally had depths +30cm, +15cm, and +5cm, but we retaped them to +15cm, +10cm, and +5cm depths since the water column was only 18cm deep. Within each set, the thermocouples are wired in descending height order on the AM25T. I had wired all the thermocouples in backwards (swapping the high and low leads) which resulted in water temperature readings around 50C. I only realized my mistake after wiring all 25 thermocouples so it took some time to fix them all.

Joe installed 3 soil heat flux plates, which were co-located with the three thermocouple profiles.
Set A: Hukseflux HFP01, sn 11325 (mux DE1)
Set B: Hukseflux HFP01, sn 11328 (mux DE2)
Set C: Hukseflux HFP01, sn 11329 (mux DE3)

Joe installed the conductivity sensor sn 5688 and eosGP sn GP20200089 on the outside of the well pipe, about 5cm above the surface. The eosGP cable was just short of the data logger box, so it needs a spliced extension before I can wire it in. Joe was then finally able to get out of the hot and humid canopy and take off the waders for the day.

We were going to install the precip bucket on the northeast corner of the scaffolding, but Joe remembered that this bucket is unevenly calibrated (the 2 sides of the seesaw do not tip at equal rates), so we brought it back to the lab to calibrate first. The precip bucket had a spider that I gave up on evicting after a few minutes of poking and shaking.

I downloaded met, camera, and USB GHG data. I cleaned flux and rad sensors. I did not top off the wash reservoir since it was still full. There was a leak in the white wash tubing that I trimmed off. We should replace the wash tubing with the black one.

The Stardot camera lost its time sometime today, so I synched it with the laptop time. We also need to change the file name from â€œsiwetlandâ€¦.jpgâ€ to â€œgilbertractâ€¦.jpgâ€ or similar.

I installed another 7550 temperature dongle to replace the one that went missing last week and tidied up the looped cables.

We installed miniDOT sn 906606 on a plastic yellow chain attached to the scaffolding. The sensor is laying in the water, so the installation could probably be improved. I would like it to be hanging in water, but still accessible for downloading data. We discussed a floating boom like we have at Mayberry, but the plant and thatch buildup might get in the way of easily moving the boom up and down. The miniDOT has a fresh desiccant pack and we made sure the sensor was on before deploying it in the water.

Joe tightened and improved the tie downs on the main tower and added 2 tie downs on the solar panel tower. He measured sensor locations and headings and checked the level of the sensors and tower. We probably want to check the level of the tower in a month or so after the tower settles a bit more.

The sonic heading was 76deg true N.

LI-7500 readings:
CO2 414ppm
H2O 805ppm
T 26.6C
P 100.9kPa
SS 99--> 99 after cleaning
LI7700 readings:
CH4 2.2ppm
RSSI 22--> 83 after cleaning

Still To-do:
Change stardot file names from â€œsiwetlandâ€¦â€ to â€œgilberttractâ€¦â€
Splice eosGP cable
Install precip bucket
Install staff gauge (maybe on fence post in the wetland)
Add mesh to holes in solar controller box
Replace 7700 wash tubing w/ black tubing
Swap 7500
Check battery voltage w/ battery load tester
Install rad cal kit from MB
Put up Arable

We left at 13:45 PDT.

0 photos found

8 sets found

Can't check MBWPEESWGT_mixed
Can't check MBEEWPSWEPGT_cam
16 GT_met graphs found