Field Notes

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Bouldin Corn: 2021-01-29 12:00:00 (DOY 29)
Author: Joe Verfaillie
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Summary: Tower fell down on the 27th? Recovered damaged sensors, undamaged sensors continuing to run.

Bouldin Corn
2021-01-29

I arrived at about 12:00. I had been worried for a few days that this tower had fallen down in the storm earlier this week because data from the Arable units had stopped sending. Then this morning I first got photos from the Arable camera on the tower that was now pointed at the ground. And then later Tyler visited the site and confirmed that the tower had fallen into the flooded field. Along highway 160 where the eucalyptus are, both sides of the road were littered in down limbs and trees.

When I arrived, the gate at the overpass was locked but I found a secret back door by exiting the highway a little further on and coming back along the levee that runs along the ditch just south of our field. Even with the recent rains this path was better than the longer route across the island to the Alfalfa site.

It was a beautiful warm and sunny day with white fluffy clouds and no wind making the water mirror the sky and lots of birds. It was ideal except for the tower laying in the water. The water was knee deep all around the base of the tower and full of little bugs going every which way. The tower was resting on its radiometer boom and the eddy equipment. The radiometers were buried in the mud and the eddy equipment was mostly under water. The eastern fence post anchor was pull straight out of the ground and dropped in the field near the top of the tower. The western fence post anchor was bent in half.

The tower had power when I arrived and seemed to be collecting data even the sensors that were under water. There was a power outage on the 27th from 00:00 to 20:00 during the height of the storm. The last data recorded before the power outage shows sustained wind of 20m/s (45mph).

The scaffolding was much too heavy and wobbly to lift whole so I removed the equipment from the upper railing, then the railing and the second level frame. Then I was able to lift the bottom frame back into a standing position. The data logger box and ground sensors including the FD chamber seemed fine. The cable for the well sensors had been torn loose from the data logger but I reconnected it and it was giving reasonable data. I put the railing back on top of the bottom layer of scaffolding and reinstalled the tipping bucket, rotating shadow band (diffuse PAR) and the HMP60 temp/RH sensor. I collected the met data, the FD data and brought in the camera card.

I knocked over the post holding the power box. I think the 4x4 post has rotted in the ground and I broke it off by pulling on it. Itâ€™s currently propped up with a fence post.

Hereâ€™s a list of the equipment that I removed and its status:

7500 sn 75H-2176 - half submerged but the connector was free of water. I removed the desiccant bottles and it seems dry on the inside â€“ no evidence of water in the windows.
7700 sn TG1-0155 - About 1/2 cup of water came out of lower body. The pressure sensor and mirror motor might be bad but the rest of the boards look okay. The head seemed sealed and dry - I pulled the desiccant bottle and no water came out.
Sonic sn 153805 â€“ The head was under water but the connector was dry â€“ it was still reporting data until I turned off the power. I donâ€™t hear any water sloshing inside.
7550 sn AIU-0614 â€“ This stayed out of the water. The pressure ports might have been briefly submerged but no evidence of water inside.
NR01 sn 2420 â€“ One side broke off and water got inside where there are some screw terminal boards and maybe the PRT. The sensors themselves seem sealed.
PAR in sn 140453 â€“ Seems sealed and was reporting reasonable numbers for being buried under water.
PAR out sn 140441 â€“ Seems sealed and was reporting reasonable numbers for being buried under water.
NDVI in sn 882103020 â€“ was under water but no obvious damage.
NDVI out sn 2046503357 â€“ was under water but no obvious damage.
PRI in sn 913003004 â€“ was under water but no obvious damage.
PRI outn sn 897103002 â€“ was under water but no obvious damage.
Camera sn 0030f4d21491 â€“ was not exposed to water â€“ still dusty inside the enclosure
PurpleAir sn 84f3ebd5ffb1 â€“ This was above water but probably got wet from the rain â€“ some rust on power connector.
Arable Mark sn C003251 â€“ above water should be fine â€“ maybe some rain in its RH/Temp bulge
Arable Mark sn C006123 â€“ above water should be fine â€“ maybe some rain in its RH/Temp bulge
Davis anemometer â€“ This was under water. The cup spindle is slightly bent but component seem to be sealed.
I also removed the two Arable game cameras. They seem fine but I will ask Arable what they want to do with them.

I left at about 16:30. I was able to go by BA, MB and SW and check on these tower with binoculars. All three of these tower seemed to be standing and unperturbed. There are a bunch of goats on the Mayberry levee.

6 photos found

20210129BC_EddySubmerged.jpg ( 2021-01-29 12:02:06 ) Full size: 1440x1920
The eddy sensors were almost completely submerged. The HMP60 stayed out of the water and the connectors from the 7500 and sonic were out of the water.

20210129BC_Pano.jpg ( 2021-01-29 11:57:51 ) Full size: 1920x479
It was a really beautiful day in the Delta except for the downed tower - warm and sunny with white fluffy clouds, almost no wind the ponds mirroring the sky and lots of birds.

20210129BC_RadiometersBuried.jpg ( 2021-01-29 12:01:14 ) Full size: 1440x1920
The radiometers were buried in the mud.

20210129BC_TowerDown1.jpg ( 2021-01-29 11:58:59 ) Full size: 1920x1440
The tower fell into the flooded field probably some time on the 27th - the power was out so the exact time is still uncertain.