Jennifer Kay and Terry Spencer

STUART, FLA.: A smelly, “guacamole-thick” muck is fouling a stretch of beaches promoted as Florida’s “Treasure Coast,” where lawmakers and residents blame the federal government, saying the algae crisis is fueled by freshwater flows controlled by Army officials to protect an erosion-prone dike.

The blue-green algae is the latest contaminant featured in yearslong arguments over water flowing from Lake Okeechobee, which is critical to South Florida’s water supply and flood control systems.

At Central Marine boat docks in Stuart on Thursday, pea-green and brown algae coated the water and smelled strongly like cow manure. Blooms that started last week in the St. Lucie River continue to spread, threatening Atlantic beaches expecting crowds of families for the holiday weekend.