Blueberry irrigation

The extension office info on irrigating blueberries says something to the effect of 'an inch of water every ten days' but also 'six gallons per day (?!!)'. I am sure that six gallons per day is more than 'an inch every ten days'. So I don't know what to make of it. Elsewhere I've heard that blueberries need a constant moisture but good drainage, so if that inch of water all came in say, one day, then going another nine days without water would seem to be overly stressful for the plant, especially when in the heat of summer. Also, calculating water in gallons is easier than calculating in inches. How many gallons in an inch of water? It is indefinite. What amount of water are the blueberry growers on this forum using? Currently I have been drip irrigating for 10 minutes three times per day for a total of about a quart to half-gallon per plant, per day. Irrigating from a water source fifty or so miles away does not sit well with me and is certainly not sustainable, so I am open to any ideas on how to provide the blueberries' evolutionary water niche without artificial irrigation.

Mine are on the very back of the property and get neglected more often than they get watered. It's been tough going the last three dry summers. But this year, with twice normal rainfall in June, they have a bumper crop. I also mulched very heavily this spring and even drilled into the ground and filled the holes with rotting tree branches (to get a hugelkultur effect). This year, I even have a volunteer new plant coming up in the blueberry patch. So my advice is to dig in a lot of mulch, mulch heavily around the base, and then add some more mulch.

I would plant a relatively water-demanding, quick to wilt plant under/around/near the blueberries as an indicator plant, and you would water the blueberries in addition to the indicator plant when this droops. Winter squash comes first to mind as a fast annual, comfrey is a good perennial for this purpose, and would thrive in the shade of the blueberries, especially if you are in a warm climate. Not sure about the pH for comfrey versus blueberry though. I know the squash will work....