Carlson Trophic State Indices
Used by Many States for Lake/Reservoir
Classification
CARLSON
TSI-P Phosphorus Index
CARLSON TSI-CHL
Chlorophyll-a Index
CARLSON TSI-SEC Secchi Depth
Index
Approximate Trophic State Boundaries, Based Upon Mean
TSI Values:
"Oligotrophic"
TSI
TSI < 40
"Mesotrophic" 41 < TSI < 50
"Eutrophic" 51 < TSI <
70
"Hypereutrophic" TSI > 70
Agreement among TSI-P,
TSI-Chla, & TSI-Secchi will be poor for reservoirs with high levels of
inorganic turbidity and/or nitrogen limitation of algal
growth.
See Equations
.
References
Carlson, R.E., "A Trophic State Index for Lakes", Limnology and Oceanography, Vol. 22, pp. 361-369, 1977.