 More heavy rain is in the forecast for the July 4th holiday weekend. It may add to worries that officials have about a bridge spanning the Blue Earth River near Mankato, crumbling after being pummeled by floodwaters from recent heavy rains. The nearby Rapidan Dam was partially breached by thundering water. The County Road 9 bridge close by is at risk for collapsing into the Blue Earth River. Blue Earth County Public Works Director Ryan Tilgis.