Equipment:
Figure 2. EC/temperature (left) and pH (right) device.
Figure 1. Equipement used to measure the water quality depth profile. Since 2017, I no longer use this analog themometer. Instead I use the digital device shown at figure 2.
- EC device-1: TDS-3, TDS/TEMP – measures EC in ppm and temperature in degrees Celsius.
- EC device-2: TDS&EC meter(hold), 0-9999ppm – measures EC in ppm and uS (not reliable) and temperature in degrees Celsius.
- pH device: pH-ATC, ROHS.
- EC device-1 was calibrated with a professional EC device. 1 ppm = 2.3331 uS (r2=0.9994, n=5, range: 0-217ppm (0-506uS))
Water quality dragonfly research:
- The EC, temperature, and pH are measured directly in the water close to the coastline.
Depth profile Liesjärvi:
Materials:
- 1.5L plastic bottle anchored with a heavy stone.
- Thick rope of >20m length that is attached to the bottle and has a knot at every 1m .
- Thin rope of >20m length with cork attached to one end.
- Small bucked to collect the water from the bottle.
- EC device-1 and pH device.
- Rowing boat
Methods:
- Measurments are taken from a rowing boat in the middle of lake Liesjärvi at a position where the water depth is maximum (i.e. 18-19 m).
- The bottle is closed with the cork and put in the water.
- At a certain depth (based on knot in rope), the cork is pulled out of the bottle.
- When the bottle is filled up with water, it is brought to the surface and emptied in the bucket.
- Immediately thereafter, the measurements (pH, EC, temperature) are taken.
- Water samples are collected at every 1 m water depth until the bottom of the lake is reached.