I did some checking around this weekend, and found an inexpensive stick anemometer that I can place in the sides of the wells. Then I can get a fairly decent idea of flow based on velocity. Last I had ever checked, anemometers were fairly pricey and didn't think we could get it in the budget...
I work on a landfill and we recently noticed that we had very low pressures of sub-surface gas migrating out of several monitoring wells. The wells are 2 inch schedule 40 PVC, 25 feet deep, reading about 70 mm/Hg. The screen length is 10 feet. The gas make-up is 50% methane and assuming 45% CO2...