Lake Data & Maps
Since at least 1979 volunteer citizen scientists and VT DEC staff scientists have been collecting data on the inland lakes, including Lake Iroquois, in Vermont. The historical data show a trend toward higher nutrient levels in Lake Iroquois. However, with the many projects undertaken by the LIA since its founding in 2007, that trend has begun to change. The Lake Scorecard shows that Phosphorus levels in Lake Iroquois are showing a significant decrease. This is an important indicator as higher nutrient levels are partially responsible for encouraging the growth of invasive Eurasian Waterfmilfoil (EWM). While nutrient levels will never be zero as nutrients enter the lake from naturally phenomena (vegetation moving into the lake, native aquatic species dying on the lake bottom, etc.) into the lake, the LIA continues to work toward preventing as much human caused sediment and nutrients from entering the lake as possible.
Data
- Lake Iroquois Scorecard: Select Iroquois from drop down menu in upper left corner, then click “view report” in upper right corner.
- Lake Water Quality Summary Report
- Lay Monitoring Data
- Spring Phosphorus Data
- Vermont Integrated Watershed Information System
Maps
Bathymetric Chart
Chart showing water depths. Download a PDF version.

Distribution of Eurasian Watermilfoil (EWM)
From the 2019 Plant Survey Report.

VT State Aquatic Invasive Species Map
View the status of invasive species across Vermont in this interactive Google Map.