I haven't looked at all the recent literature on watering trees in a drought, but this link is of interest, EdgarB.
Look towards the end of it re your own trees.
Back in california we pushed distributed drip irrigation (slow) for getting to the deeper roots, and mulching.
I agree with Butrflynet re calling your local agricultural extension of state or county or university.
Are yours native pines? That might make a difference.
Worse comes to worse, call a certified/licensed arborist out for an hour. There would be a charge for that, but it might well be the best advice you'd get, re watering/how to water, and re any limbs to cut.