Field Notes

Hill Slough: 2024-01-11 16:15:00 (DOY 11)
Author: Daphne Szutu
Others: Joe

Summary: Swapped 7700 for calibration, Replaced CR23x enclosure clasp, EXO brush not working--needs more attention, HMP fan power wire broken--fixed

2024-01-11
Hill Slough

Joe and I arrived at 16:15 PST for an off-cycle visit to calibrate the 7700 and for some maintenance tasks. Traffic on Highway 12 between here and Rio Vista was unusually quiet--we hardly saw any cars in our direction on the way here. It was a cool, partly overcast, and approaching dusk. It was near high tide and the staff gauge read 6.23ft at 16:25 PST.

We swapped the LI-7700 for calibration sn TG1-0421 came off and sn TG1-0155 went on. After the swap, we returned the spiky hat and the wash sprayer to their proper locations. I connected the new 7700 in the 7550 software, rebooted the 7550, and confirmed the correct 7700 was connected in the 7550 software and there was no yellow triangle error icon.

I didn't download the data but checked that the real-time met data looked ok and the GHG logging status was ok.

The 7500 read: 420ppm CO2, 250mmol/m3 H2O, 11.5C, 102.3kPa, 103SS
7700 old sn TG1-0421 read: 2.06ppm CH4, 59RSSI
7700 fresh sn TG1-0155 read: 2.02ppm CH4, 89RSSI

One wire on the HMP fan power cable had corroded off. I disconnected the power, trimmed the cable back to re-wire it, and reconnected the power.

Joe replaced the upper clasp on the CR23X enclosure at the channel. He had to remove the CR23X from its mounts temporarily to get into the box. The bolt was a little long and the clasp wouldn’t close, so he used the blue-handled wire cutters to cut the bolt short.

I pulled up the EXO just to check on it. Two fish fell out of the plastic guard as I pulled it up; there was a big pile of fish eggs on the inside of the guard and a handful scattered on the sensors. The brush was stopped over the pH sensor and all of the sensors were pretty dirty. I don’t think the brush has been working since it was replaced on 2023-12-13 around 11:00 because WipeV has been 0. I’m not sure how good the optical data is past this date (turbidity, fDOM). Conductivity and pH might be fine. I rinsed off the sensors and manually twisted the brush back to its plastic “parking garage.” The Xylem folks at AGU told me I can program the brush “parking” position, but I need to check the manual. The EXO is due for calibration at the end of the month, so I’ll remove it next week when we do the regular Delta data circuit.

We measured the conductivity using our handheld YSI probe. We measured the pore water using the first and second pulls from the syringe. They were pretty similar but the second pull was a little fresher and cooler, which I would expect when comparing water that was been inside the tubing for a while with freshly drawn pore water.

Sample, Temperature-compensated conductivity, Sample temperature, Time
Porewater_flush, 9.51 mS, 9.8 degC, 16:45 PST
Porewater, 9.48 mS, 9.3 degC, 16:45 PST
Surface, 5.67 mS, 9.9C, 16:45 PST

We left at 17:00 PST.

2 photos found

20240111HS_TinyFloatingPeatIsland.jpg ( 2024-01-11 16:09:08 ) Full size: 1440x1920
A tiny floating peat island