Tuesday, June 19, 2012

Hydrochemistry and piezometers

"Ughh, I swallowed a mosquito" was what I heard when we were installing a piezometer in the afternoon today. This was all the more surprising because it came from a student who is known for cooking exquisite meals.

In the morning, Michel and I had gone to the students in Barra to pick up the water samples that they had collected in their catchments over the past week. There were nearly a hundred samples and they all had to be acidified before we could ship them to the laboratory in the Netherlands where they are to be analyzed before our return.

Presa Velha group sampling Fonte Juncal

With this out of the way we went to Montouro for a coffee and a "Mesas catchment" group meeting. As Miguel finally took a day off we met up with the remaining members and discussed what they were up to. They wanted to know how deep the Cretaceous clay was below the Quaternary sands near the village of Covoes, after seeing a geophysics VES that told them that it should be at about 2 m depth. Installing a piezometer also allows you to know the waterlevel in the area and the quality so we took our cars and went for a spin with the pulse auger set.

Ilaria making a piezometer hole in the ground, Valentina, afraid to get sucked in...
This was easier said then done as there proved to be much gravel in the Q-sands, which made it difficult to get through, without bringing in the full weight of Waterloo and the endurance of Groen.

Michel going through gravel layer

However, it was done somehow, we reached the Cretaceous clay at 3 m. Piezometer VU48 was made, water level sensor prepared and everything noted down in field book and in the Ipad.Group very happy...

Happy Mesas group after piezometer installation

Somewhat earlier, the Sao Romao group had also installed the VU47 and VU46 piezometers in their area under supervision and mental coaching of Ilja and Michel.

Sao Romao group looking for groundwater in a grey tube...
Things are thus going well!!! Except for the river hydrology perhaps, Tabuaco and Mesas streams are drying out, leaving the discharge people without anything to measure.

Miguel and his Mesas stream, only a few days earlier when there was discharge...
So they are the only ones here who would enjoy a good rainstorm.

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