Day 6: Fixing bad data + making water quality measurements

Our data analysis from yesterday suggested that a few of the points we have measured in the past might have errors.  The resistivity values took an unusual turn at the deeper part of one particular sounding.  However, for resistivity measurements, an anomaly at depth may be representative of a surface feature somewhere along the line that just changes the possible paths for electrical current in the ground.  

So, in order to identify the errors, we went back to the field and surveyed that sounding for nearby disturbances, such as buried metal, culverts, or other obstructions that would change the conductivity of the ground.  We found that one of our electrodes was very close to a culvert during the final measurement, meaning that the measurement was suspect.  Tonight, we were able to remove that reading from the inversion and produce a new result.  

This afternoon, we  went on a trip to several local sources of water with our colleagues at the Water Resources Management Agency.  This included a well and a slowly-flowing stream which we tested for conductivity and pH.  Although this particular well was not in Roseau Valley, it is an example of a type of water resource that could be developed in Roseau Valley.  

Today's lunch spot: beside the largest river in the Roseau Valley. 

Sending a high-tech sampling device (a measuring tape and then a plastic cup on a string) down into the well to collect water.

Testing the pH of the small river at our site visit this afternoon.