pdf WQ6 Results From Island Wide Monitoring, Trophic State Index (TSI) Analysis, Summer 2019

Author: R.A. Smiith

Author Affiliation: LCWC

Journal: Unpublished Report



Les Cheneaux waters remain of a highly desirable quality for recreational use.

Ratings of 2019 water samples fell within expected trophic (nutrient) ranges for inner and outer island zones of the Les Cheneaux Islands. Variables quantified for Les Cheneaux water samples were: Total Phosphorus (TP), Soluble Reactive Phosphorus (SRP) and Chlorophyll-a (Chl-a).
TP and SRP values were found to be about equal in concentration. Chlorophyll-a was used as an indirect measure of phytoplankton concentration. As Chl-a values increase the SRP is metabolized and, therefore, decreased. Seasonal 2019 temperatures ranged from an average of 10.5 C (51 F) for the inner island zones to 16.5 C (62 F) for the outer island zones. Water clarity remained high to a point that the Secchi disk could be read when lying on the bottom at sites 2, 4a,8 and 9 where the depth ranged from 10ft to 45ft.