A LONG-standing red alert for Blue-green algae has been lifted by WaterNSW for two of the region's biggest water ways.
Alerts for an area of the Namoi River downstream of Keepit Dam and Split Rock Dam have been lifted after being in place for over a month.
The alert for the area of the Namoi River downstream of Keepit Dam had been in place since March 13 after reports of an algae breakout.
Blue-green algae occur naturally and can reproduce quickly in favourable conditions where there is still or slow-flowing water, abundant sunlight and sufficient levels of nutrients.
Blue-green algae usually appear as green paint-like scums on the water, near the edges, or as greenish clumps throughout the water. It makes the water appear dirty, green or discoloured and generally has a strong musty or earthy odour.
Two more red alert warning's remain in place across the region, including in the Manilla River near Barraba and at Copeton Dam (Wonulla).
People who believe they may have been affected by blue-green algae are advised to seek medical advice.