I got it solved, simply by opening it up at the bottom (no jets, the 3" line unobstructed ) and letting it run wide open for over 48 hours straight. I think what happened, sure actually, I jumped the gun in getting it back on line, while there was still a large drift directly over a section of the line that doesn't totally drain due to a hump in it caused by the terrain. Some remaining ice slowed the flow possibly, allowing the sediment to build, sediment heavier than usual the rest of the season because of the heavy spring runoff. Once the normal flow is established, any sediment is continually whisked thru the system without any harm. I've seen other hyrdo installs, with very involved catchments that nicely channel the water in a controlled fashion over the intake screen, with provisions made to allow any sediment to settle before entering the pipe. Most of these involve concrete and escavation in or around the streambed, and most don't have the extremes of flow this stream has.
My intake is simply a 8" pipe jammed into the county culvert at the top of my property, with a trap door at the end and a slot cut in the bottom, lowering or raising the end trap door controls how much water hits the screen. On the initial setup, it took maybe 15 minutes to find a place for the screen box, move a few rocks, set the pipe (which rest directly on the screen box) and I was in business! The main benefit, besides it being quick and easy, was that it involved zero disturbance to the streambed, which my state water board discourages, without more permits and inspections and general hassle. The other benefit is it positions the box as high as possible, giving more head pressure, any other arrangement would result in a loss of head by a few feet and that would be intolerable! After 17 years, I think I can say it's crude as heck, but it WORKS. I have never jumped the gun and turned it on with snow still on the ground before, I got sloppy and that late spring heavy snow storm didn't help, next year I'll, like all my earlier years, wait until it's ALL gone before booting it up. I am now back to enjoying the warm fuzzy feeling knowing I'm putting out 33-34 amps at 25.6 volts, into my grid tie account, for the next several months, which still has a surplus of almost 5,000 KWH after getting thru the winter, by late fall it'll be back up to it's usual 8-10,000 KWH, as i also have about 9 KW of PV. Thanks for the various suggestions!