On 4 July 2024, WWLA embarked out to Lake Puketirini in Huntly for a boat survey. Their mission was to dive deep into the lake's temperature and water quality, especially within the top 20 meters.
Equipped with two Solinst LevelLoggers, the team measured pressure, temperature and conductivity at various depths. Using a game fishing rod and a heavy sinker, they sent the loggers down to approximately 60 meters and recorded data on their way back up. They mixed up the ascent speeds for each deployment to ensure sensor had time to adjust to the varying pressure, temperature and conductivity, and ultimately obtain a thorough profile.
For water quality, they took samples from 5, 10, 15, and 20 meters down using a Van Dorn sampler. These samples covered a wide range of factors like metals, nutrients, and general water quality indicators.
What did they find? The surface temperature started at 13.3°C and dropped quickly to 12.55°C at 24 meters. Between 24 and 40 meters, it decreased slightly to 12.5°C, then rose a bit to 12.6°C near the bottom. Therefore, the temperature variation over the full depth of the lake was only 0.8°C.
Conductivity at the surface was 222.4 µS/cm, reducing steadily to 218.1 µS/cm at 27 meters, then stabilizing before increasing again near the bottom. The variation in conductivity was minimal, only about 5 µS/cm over the depth.
Even with some minor boat swings due to wind, the data showed consistent trends. These preliminary results gave great insights into the lake's temperature and chemistry stratification (or lack thereof). WWLA's approach ensured accurate data collection, setting the stage for more detailed analysis.
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