DD1,
March and April are not good months for wind-free Texas days. If you're just going to treat a swath across the dam, is your plan to apply Soilfloc from the shore on foot or by boat? If by boat, a couple of guys on opposing shores with long ropes should be able to gradually pull you across the area you want to treat. I'm out of town until 3/14 but willing to help when I return. Let me know.
Dave Goyne
(l.goyne@sbcglobal.net)