Lake conductivity and temperature profile

Last winter, we determined the conductivity and temperature profile of the Pieni-Valkeinen pond using the CastAway measuring device (Figure 1). We made ice holes every 20 meters and measured the depth, conductivity and temperature along the depth. The openings were made on a straight line between the pond's inlet and outlet (Figure 2).

Figure 1. Winter gives the opportunity to carry out various studies also in the central parts of the pond. The pictures show the prevailing conditions and the measuring device CastAway. 

The CastAway device is intended for making vertical measurements and it automatically records the measurement data when the device is lowered close to the bottom of the pond. We measured each ice hole and with the help of the obtained data we interpolated the conductivity and temperature profiles of the measured cross-section. Data processing and visualization was done using Matlab. The exercise was part of the Environmental Measurement Data Management course.

Figure 2. Location of measurement points.

Figure 3. Lake temperature profile.

Figure 4. Lake conductive profile.

Conductivity in general describes the salinity of the water, which gives an indication of water quality, for example. The profile in Figure 4 shows the effect of stormwater on the water quality of the pond inlet (left side). Similarly, the higher readings of the bottom can be seen. With the help of the measurements and data analysis, new information can be produced for examining the water quality of ponds.

This was a great exercise in combining field measurement and Matlab-based data analysis. In a couple of weeks we will start a new course again, we know it's going to be fun by the Pieni-Valkeinen!

Teemu