General Instructions

Observations should be made at the same location once per week. Observations must be made between 10:00 AM and 3:00 PM. At that time the cyanobacteria have had a chance to rise from lower in the water column, but cells are not yet likely to have ruptured from the heat of mid-day. All observations submitted and approved will be posted on the Vermont Department of Health cyanobacteria tracker. Anyone providing reports should include information on the extent and type of cyanobacteria and plant growth, the color of the water, and rate the cyanobacteria intensity. The rating scale runs from one (a, b, c, or d) to three, with one being clear water with little to no cyanobacteria present and three being a cyanobacteria bloom in progress.

For category 2 and 3 conditions, three digital photographs should be submitted via the online form. Remember to avoid direct contact if the bloom is well developed.

Category 1a, Generally Safe: No cyanobacteria observed — clear water

Any organisms floating in water column are clear (e.g. insect ‘skins’) rather than green. Leafy or grass-like plants (including duckweed) may be present. Foam may be present.

Category 1b, Generally Safe: No cyanobacteria observed — brown and turbid conditions

Brown turbid low visibility through water column

Category 1c, Generally Safe: No cyanobacteria observed — other phenomena

Other material that doesn't count as cyanobacteria might include:

  • Long strands that tangle around paddles or boat hooks
  • Small bright mustard yellow (pollen) or grass green (duckweed) particles
  • Algae attached to rocks or the lake bottom.

Category 1d, Generally Safe: Little cyanobacteria observed — tiny specks present, but no striations or clumps — include photos

Green floating balls may be visible, but only on close inspection and in densities so low that they do not impair recreational enjoyment of the water. There are no surface or near shore accumulations of cyanobacteria.

Category 2, Low Alert: Cyanobacteria observed, but at less than "bloom" levels — include photos

Numerous green balls (pinhead size or larger) floating in water column, but not accumulated at water surface. Possible small (smaller than a softball) patches of cyanobacteria accumulation. Open water color not green. Possible narrow band of cyanobacteria accumulation at shoreline.

Category 3, High Alert: Cyanobacteria bloom observed in progress — include photos

Extensive surface scum on water – color may range from green to electric blue (not yellow/pollen). Usually accompanied by a thick accumulation at shoreline. Open water appears green.