WATER QUALITY SUMMARY

ETNA POND, Etna

MIDAS: 2274, Sample Station # 1

The Maine Department of Environmental Protection (ME-DEP) and the Volunteer Lake Monitoring Program (VLMP) have collaborated in the collection of lake data to evaluate water quality, track algal blooms, and determine water quality trends. This dataset does not include bacteria, mercury, or nutrients other than phosphorus.

Water quality monitoring information for Etna Pond has been gathered sporadically since 1980. During this period, 4 years of basic chemical information was collected in addition to Secchi Disk Transparencies (SDT). In summary, the water quality of Etna Pond is considered slightly below average based on measures of SDT, total phosphorus (TP) and Chlorophyll-a (Chla). The potential for nuisance algal blooms on Etna Pond is moderate to high.

Water Quality Measures: Etna Pond is a highly colored lake (average color 82 SPU) with an average SDT of 3.0 m (10 ft). The range of water column TP for Etna Pond is 14 - 39 parts per billion (ppb) with an average of 24 ppb. Chla ranges from 2.1 - 7.4 ppb with an average of 6.0 ppb. Recent dissolved oxygen (DO) profiles show little DO depletion in deep areas of the lake. The potential for phosphorus to leave the bottom sediments and become available to algae in the water column due to low dissolved oxygen (internal loading) is unlikely. However, because the pond is shallow, resuspension of sediment including phosphorus due to strong winds is possible.

Etna Pond is shallow and has wetland areas around it. SDTs are occasionally limited by the shallow depth in Etna Pond. High color levels from adjacent wetlands also reduces SDT readings; however, higher chlorophyll levels indicate that occasionally algal growth limits transparency as well. Observed water quality is typical of this type of lake.

See the Maine DEP Explanation of Lake Water Quality Monitoring Report for measured variable explanations. Additional lake information can be obtained by contacting Maine DEP at 207-287-3901 or VLMP at 207-783-7733, and at these Websites: http://www.lakesofmaine.org and http://www.maine.gov/dep/water/lakes/index.html and http://www.mainevolunteerlakemonitors.org .

Filename: ETNA2274, Revised: 12/06, By: jp