What Does the Information Mean?

Citizen volunteer data sets confirm the general impression that Lake Martin is clean, but that portions of the upper part of the lake are becoming degraded. This has been verified by ADEM, universities and others in studies that have been more technical but with less sampling frequency than that of LWLM.

"Lake Martin is the jewel in the crown that is the Alexander City-Dadeville area."
Bruce Wallace, Publisher
Alexander City Outlook and Dadevile Record

"I have lived on or near Lake Martin all my life and wouldn't want to live anywhere else in the world."
Doug Patterson, Striped Bass Fishing Guide, 8 years

Lakes are commonly rated and compared according to their "trophic state." This is related to algal densities stimulated by the amount of nutrients (especially phosphorus) received from the watershed. "Oligotrophic" lakes have low levels of nutrients, "mesotrophic" lakes have moderate levels, and "eutrophic" lakes have high levels (AFA 1998).

It is generally believed that concentrations of an aquatic plant pigment, called "chlorophyll a" is the best indicator to use for calculating the Trophic State Index (TSI). When TSIs are above 50 (eutrophic), this usually means that a lake is becoming polluted by too many fertilizers and other nutrients. In general, eutrophic lakes have larger fluctuations in algal blooms, dissolved oxygen concentrations and other water quality variables. This, in turn, stresses fish and can lead to fish kills.

The graph below indicates that in 1989, Lake Martin had the lowest TSI of more than 20 lakes studied. In that sense, it was the "cleanest" lake in Alabama. Other lakes in the Tallapoosa River watershed (e.g. Harris, Thurlow and Yates) had generally lower TSIs, and lakes in the Coosa watershed (e.g. Jordan, Weiss, Logan Martin, Neely Henry, Lay and Mitchell) had generally higher TSIs.

What has happened to Lake Martin's trophic state in the decade following this study?

This report was compiled by Alabama Water Watch program personnel
in partnership with Lake Watch of Lake Martin.