Field Notes

<--2022-06-28 07:20:00 | 2022-07-26 16:00:00-->
Other sites visited today: Gilbert Tract | East End | West Pond

Hill Slough: 2022-07-13 09:45:00 (DOY 194)
Author: Daphne Szutu
Others: Ari

Summary: Regular data collection/cleaning, super low water level, installed EXO sonde in channel, moved miniDOT to channel, tested batteries--removed 2 bad ones, new picam code, installed sipper for soil pore water samples

2022-07-13
Hill Slough

Ari and I arrived around 9:45 PDT--it was her first visit since the site has been flooded in October! Just how the field schedules have worked out since then.

It was mild and windy with clear skies. It was almost low tide. The water level was very low and still getting lower. The water level stayed below the staff gauge the whole time we were there. Low tide was around -12cm (-0.4ft) today because the full moon was this morning. At 14:15 PDT, the staff gauge was 3.82ft (5.5cm below the staff gauge).

We’ve been losing data overnight since mid-June, which is suspicious because the days are long and sunny. However, the battery bank sn BB-HS is older, flooded deep cycles from July 2018 that were originally from EP, then SW Temp tower, then HS.

I unlocked the battery box, turned off the 5A fuse to the tower, and pulled all the batteries out to test them with the load tester. Joe had reminded me about not shorting anything against the metal box. After unscrewing the battery cables, I wrapped some of the ends in electrical tape to prevent it from making contact against the walls of the box when moving batteries around. I was momentarily bewildered that some of the battery terminals had 9/16” nuts and some had ½” nuts—Joe must have run out of the ½” nuts because I’m sure he would never use two different sizes unless he had no other option. [Joe: Batteries sometimes come with different size nuts and threads - I think to help prevent you from hooking them up backwards.]

2 batteries tested bad, 2 tested good, and 1 tested good but closer to weak. I removed the bad batteries from the system and wired up the 3 good ones. The good ones all needed water, about 3-4L each. I didn't check the water on the bad batteries since we were bringing them back to the lab anyways. The pump sprayer didn’t work but Ari had some syringes and tubing on hand for taking water samples. She used the syringes to carefully refill the batteries. I just poured directly from the gallon bottles, trying to minimize splashing.

I cleaned and sealed the terminals on the good batteries. One of the bad batteries had corrosion on one terminal but the other batteries were ok.

The tower load was 1.4A when we arrived, 1.8A after rearranging the batteries.

At the tower, I downloaded met and USB GHG data. Ari cleaned flux and rad sensors. The reservoir was 80% full; Ari refilled it. I checked the 7700 fuse; it looked fine and there was no moisture in the fuse cap.

The 7500 read: 403ppm CO2, 681mmol/m3 H2O, 21.9C, 101.5kPa, 97SS – 98 after cleaning
The 7700 read: 1.92ppm CH4, 45RSSI – 72 after cleaning

I downloaded miniDOT data, swapped its desiccant, and Ari deployed it in the channel at the same height as the EXO.

I started downloading the picam photos but the download crashed almost at the end of the download. It wasn’t showing up anymore in the network list. I power cycled the picam and was able to reconnect and start the download again. After the download completed, I cleared the photos and upload the Joe’s new pi code that has new red/blue gains (R=1.8, B=1.8) for fwb photos and more efficient (lossy) jpg compression. I changed the file permissions to allow x for all (rwx r-x r-x) and rebooted the picam. The new software seems to be running fine. I tried to change the picam clock but it didn’t seem to be sticking. I kinda remember there might be some other setting I need to change, maybe related to US vs. UK time formatting or something. The picam clock is fast by about 10min, so it won’t make a difference for GCC calculations.

The eosGP and HYDROS21 seem like they're still not quite at the right height by the tower. The eosGP is still being exposed to air at lower low tides. The HYDROS21 was still underwater but also buried about 5cm under the soil and not measuring the surface water. I didn't really see any other ponds or depressions close to the tower. The channel is >30m away from the tower met box, so I don't think we can extend the cables like we did at GT. Maybe we can set up another datalogger at the channel. We would need to run power all the way there but that's doable (especially if we're upgrading to 24V before the winter).

Ari installed a sipper under the tower by the grounding rod so we can take soil pore water samples, which Ari hypothesizes has a much different conductivity than surface water. There is a syringe and plastic vial in the yellow/black plastic toolbox. For future visits we can extract water using the syringe and measure the temperature-compensated conductivity using the handheld YSI probe. We need to make 3 draws with the syringe: (1) Draw a full syringe of sipper water to flush out stored water in the tubing, (2) Draw some sipper water to rinse out the syringe (or use DI water) (3) Draw a full syringe of sipper water for your sample and dispense into the plastic vial. The porewater sample we took measured 24 mS/cm.

We installed the EXO2 sonde sn 22C103416 in the channel off of the boardwalk with the following sensors:
Turbidity sn 22E106072
FDOM sn 22E100649
pH-ORP sn 22D102641
The black plastic sensor guard on the EXO has copper mesh surrounding it on the sides and bottom, secured with a hose clamp. For now the sensor is hanging by a yellow plastic chain attached to the handrail. The yellow chain is attached to the EXO handle with a carabiner and a ziptie as backup. I'm not sure if the carabiner was stainless steel, but I'm going to get some new stainless steel carabiners at Ace anyways since I used our last good carabiners. The EXO field cable is tied up next to the yellow chain.

Right now, the EXO is just hanging in the water. It wasn't moving around too much in the water since it's pretty heavy, but it was low tide when we were there, so it might move around more with more water in the channel. Ari would like to stabilize its vertical position so it doesn't bob around too much and add noise to the water level data. We can collect data via the field cable without moving the sonde, but Ari plans to remove the sonde every ~3months to bring it back to the lab to clean and calibrate.

Ari got in the water with waders and made some measurements of equipment height.

Soil to sonde top of black handle = 118cm
Soil to sonde flat yellow top = 112cm

We checked the EXO data before we left. It generally seemed fine, but the wiper did not seem to be moving during deployments, only when we manually wiped it using the EXO software. We downloaded the deployment configuration and Ari will e-mail EXO for help.

We left at 14:50 PDT.

0 photos found

4 sets found

20 HS_met graphs found