It’s clear what these are likely to be. We’ve seen them before. Hydrogel.
An update to the article does note that many viewers called in to say it was water-storing Deco Beads. Hoo-rah. Someone knows!
Last year (on the same date, as pointed out by Who Forted? Magazine), a similar event occurred in the U.K. when blue spheres were found after a rain. Doubtful News was quick to guess that it was hydrogel balls. Indeed testing showed it indeed consisted of sodium polyacrylate, an absorbent polymer. These are super-absorbant materials that are used in diapers, absorbant pads and in agriculture uses.
Had I to make a best guess about how this purple pile got there, they were dumped. Perhaps the dry material inadvertently got wet and was dumped by a truck transporting materials. Or it was spilled. Weird, but no big deal.