Not taking a stance either way, as that is significant. Just putting the math in perspective.
1. I'd assume 980,000 gallons/day is a maximum, as in permitted amount, not an average, and very unlikely that it's taken EVERY day? Correct? Would help to clarify.
2. At the gauge station, the average August flow of Tunkhannock Creek is approximately 22 cubic feet per second.
3. 1 cubic foot = 7.48 gallons. So that's 164.56 gallons per second. There are 86,400 seconds in a day. Hence, 22 cubic feet per second = 14,217,984 gallons per day. So if this well truly took the full 980k gallons every day, and all of it was upstream from the gauge, that equates to a little under 7% of the typical August streamflow at the gauge. If all 4 of them did, then it's 28% of the typical August streamflow.
Those are significant numbers. That said, even if they did take that kind of volume/day on a regular basis, some basic flow controls could pretty easily prevent any major impacts. You could specify a minimum flow rate where they can extract. Or you could set up the maximum allowable volumes to be on a sliding scale, so that when flow rates decrease, allowed volume decreases in kind.
But yeah, if 4 wells are allowed to take that per day, and all 4 decide to take the maximum during a low water period, the impacts aren't insignificant here.