Field Notes

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Gilbert Tract: 2023-03-23 10:00:00 (DOY 82)
Author: Daphne Szutu
Others: Dennis, Joe

Summary: Improving boardwalk, replaced dissolved CO2 eosGP sensor, replaced sensor extension box, downloaded channel miniDOT, changed ADCP to 1min sampling frequency/duration, installed more teabags, visitors from UCB CEE

2023-03-23
Gilbert Tract

Dennis, Joe, and I arrived around 10:00 PDT. It was sunny and cool with some nice puffy cumulus clouds, and very windy with some strong gusts. We had another bomb cyclone storm a few days ago and at least one more rain storm is expected next week. Today is mostly maintenance day to improve the boardwalk, and we also collected data. When we arrived the water level was pretty high and the staff gauge was >90cm. At 12:27 PST, the staff gauged read 57cm.

At the gate we met up with Drew and Youngseok from the CEE department on campus. They are developing techniques for ground-based and drone-based methane measurements so they visiting our sites as a potential place to measure. I think their previous experience is mainly in methane emissions from landfills. It was pretty windy today so they didn’t end up flying.

Marc from Hydrofocus also stopped by to say hi on his way to check on their well level sensors. Hydrofocus is studying how the tidal action of Gilbert Tract might affect the hydrology in neighboring parcel Emerson and on Jersey Island. One hypothesis is that the tidal flows in and out of Gilbert Tract might increase groundwater levels in nearby areas. Jersey Island is/was used as a place to spread solid waste, so they have some pumping limitations. So far the lag between Gilbert Tract and Emerson Parcel seems to be between 30-60min, so the USGS 15min stage data is sufficient. However, the lag between Gilbert Tract and Jersey Island may be less than 15min. Marc requested we change our ADCP to collect data at 1min intervals for a few weeks so they can analyze the higher frequency data. (Ari approved of this change.)

Joe and Dennis got started with improving the boardwalk. The first three lengths of boardwalk have plastic pipe legs that were designed to have adjustable heights, but they have started becoming unstable. The fourth boardwalk has fixed-height legs made out of pressure-treated lumber posts that are hammered into the ground: much more stable. Today they removed the legs on the first three lengths of boardwalk and replaced the legs with fixed-height legs made out of pressure-treated lumber. The bottom of the legs are cut into a point and hammered into the ground as far as possible.

I replaced the sensor extension box that is usually clamped to a metal pole and propped up on the far end of the third boardwalk. This box connects the eosGP, HYDROS21 CTD, and Campbell conductivity probe to the datalogger. The old box had a broken latch and was very crowded inside with a screw terminal and the conductivity sensor interface. The new box is bigger and screws shut (we couldn’t find the original screws for this box so we had to use too-long screws—not ideal but ok for now). Before the fall, I need to remember to put mothballs in here to keep the ants out. The new box is on the same metal pole, and the pole is now screwed onto the boardwalk leg. The extension cable that connects to the datalogger needs to be re-run soon before the emergent reeds get too tall. Right now it is threading through senesced vegetation and it’s going to be a mess to re-do once the new growing season starts.

I swapped out the eosGP sensor that has not been working for the past few months: 0-2% probe sn GP20200089 was removed and 0-2% probe sn GP20210002 was installed. Since the ranges are the same, the met processing code shouldn’t need to change.

I think I got all the water sensors back to the same height as before today. When the staff gauge read 57cm, the water sensors were 53cm below the water. The previous time when we adjusted the water sensors (2022-08-24): when the staff gauge was at 28cm, the sensors were 23.5cm below the water. Today after all of the changes, the sensors are still about 4-5cm above the bottom of the staff gauge.

I downloaded met, cam, USB GHG, and miniDOT data. The camera card did not mount at first, but was ok after trying again. Maybe this card is getting old.The wash reservoir was 90% full; I refilled it. I cleaned the 7700 but skipped the other sensors since they looked ok.

In preparation for the Knightsen field trip, I installed another group of 3 teabags in the water to complement the one I installed in early March. Both sets of teabags are near the water level sensor post just off of the bard end of the boardwalk. Today’s teabags are labeled “March 14” even though it’s now March 23rd.

The 7500 read: 427ppm CO2, 339mmol/m3 H2O, 13.3C, 102.3kPa, 103SS --> did not clean
The 7700 read: 2.0ppm CH4, 50RSSI –> 85 after cleaning

We went on to the channel around 13:30 PDT. By this time the water level was still low but the tide was starting to come back in.

Joe downloaded Flo’s data. I downloaded the old deployment and then changed the deployment so both the sampling interval and sampling duration from 300sec to 60sec to help with Marc’s project. The old deployment is saved as “GT_20230323retreived.sontek_system_config” and the new deployment is saved as ‘GT_20230323new.sontek_system_config,” both in D:/GilbertTract/SL1500 on sneakernet.

I decided to grab data from the channel miniDOT, which is co-located with the USGS EXO. I dropped the ½” ratchet in the water on my way in, but was able to find it and pick it up again with our handy telescoping rake. I also spent some time using the rake to find the other ½” ratchet we dropped back in November, but no luck there.

I removed the whole EXO mount and brought it back to shore. There were two sculpins and two clutches of eggs nestled between the EXO and the metal backplate. Joe instructed me to use the ratchet or another tool to poke the sculpin off and back into the water, because some species of sculpins have toxins in their spines. Later Joe did some more research and found that the venomous ones are ocean "sculpins" (scorpionfish, Suborder Scorpaenoidei), where as the freshwater "sculpins" (Suborder Cottoidei) do not have the same venemous spines.

Joe downloaded the miniDOT data and we attached it back to the EXO mount. I dragged everything back into the water. The mount attaches to a post in the channel with two bolts, and I had a really hard time getting both bolt holes to line up at the same time. The water level was getting closer to the top of my waders and it was hard to see underwater. Eventually Joe ran back to the truck to put on his waders and got in the channel to help get everything attached securely. Maybe we need a better way to mount the miniDOT so I can access it more easily for our quarterly downloads.

We left around 14:45 PDT.

0 photos found

8 sets found

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