A Clear Look at Water Color

If you live in the Piedmont region of Georgia and long for your lake to have the perfect clarity of a clear mountain stream, you're likely to be disappointed. Lakes and ponds -- especially those within urban watersheds -- are subject to a variety of influences that impact water color and clarity. Vegetation, water chemistry, geology of the lake bottom and erosion within the watershed are all factors. But a lake that's less than crystal clear is not necessarily unhealthy, and water clarity naturally varies throughout the year as cycles of vegetation growth and decomposition occur.

Colorful Causes: Tea-colored water is generally caused by tannins from slowly decomposing organic matter and is no cause for concern. Muddy brown or reddish-brown water can indicate sediment influx from erosion and runoff; dredging may be warranted, along with an identification of the source to reduce future build-up. Brown water does not indicate fecal contamination -- the type of organic acid generated by human and animal fecal decomposition is actually not pigmented and therefore does not affect water color. Green or brownish-green water with poor clarity is usually caused by exacerbated algae and phytoplankton growth, a result of excessive nutrient build-up. An algal "bloom" can cause a soupy look and bright green color. Summer is the peak season for algae issues.

When to Be Concerned: Excessive algae can cause nuisance odors and even fish kills. If you see a sudden, drastic change in water color or clarity (unless the change in clarity is directly attributable to development issues in the watershed) and/or notice a foul odor, you should consult a professional.