Is it the amount of drawdown that determines the mixing
Does mixing result due to drawdown (similar to bailing) when one has a drawdown of more than a 10th of a meter?
It's not the amount of drawdown that determines the mixing, it's whether the drawdown stops. The mixing occurs as the drawdown continues. Once the drawdown stops, and we continue to pump, then the effects of mixing, the blending of stagnant water and spring zone water, should essentially be diminished and we should end up with the sample just from the spring zone. So drawdown of more than a 10th of a meter isn't the issue – getting stabilized pumping water is all that counts.
It's not the amount of drawdown that determines the mixing, it's whether the drawdown stops. The mixing occurs as the drawdown continues. Once the drawdown stops, and we continue to pump, then the effects of mixing, the blending of stagnant water and spring zone water, should essentially be diminished and we should end up with the sample just from the spring zone. So drawdown of more than a 10th of a meter isn't the issue – getting stabilized pumping water is all that counts.