The Vermont Lay Monitoring Program is a cooperative effort between the Vermont Department of Environmental Conservation and lake users. People from all walks of life who are actively involved in lake protection make up the Lay Monitoring Program.

The LMP was established in 1979 and continues today with the same goals:

• to describe water quality conditions on each lake participating in the program;
• to establish a database on each lake useful for documenting future changes in water quality; and
• to educate and involve lake residents in lake protection.

The LMP samples a lake for total phosphorus, chlorophyll-a concentration, and water clarity.

Total phosphorus is collected to determine a lake's level of nutrient enrichment. Since phosphorus is typically the limiting nutrient in a lake system, when in excess, it is the nutrient that can cause the most productivity (aging) in the lake. Excessive phosphorus feeds aquatic plants, algae and other plankton (free floating, aquatic life), increasing a lake's productivity.

Chlorophyll-a is the green pigment in plants and algae. The concentration of chlorophyll-a in a lake is used to describe the amount of algae in the lake. Generally, lakes with high phosphorus concentrations will have increased algae growth.

Water clarity is measured by using a Secchi disk, an eight inch diameter, black and white painted disk. The disk is lowered into the lake by a rope, marked in meters, until it disappears from sight, at which point the lake's transparency is measured. Generally, the more algae, the lower the water clarity.

Why measure total phosphorus, chlorophyll-a and water clarity? The primary cause of lake problems is from increased phosphorus. Human activity along a lake's shoreline and in the watershed can accelerate the amount of phosphorus entering a lake.

Sources of phosphorus include:

• shoreline erosion
• fertilizer run-off
• run-off from dirt roads
• failing septic system
• agriculture runoff
• residential runoff
• erosion from logging
• erosion from construction

Unnaturally high levels of phosphorus cause excessive aquatic plant and algae growth, which lowers the water clarity. Additionally, nuisance plant and algae growth can interfere with boating, swimming, fishing and other recreational activities. As the excessive growth dies back each year it falls to the lake bottom, causing sediments to build up more rapidly. When the natural environment of a lake is altered, the species of fish and other wildlife in the lake may also change.

For individual lake data click here.

How to join the LMP

All water quality sampling equipment is provided by the Department of Environmental Conservation. The monitor supplies the time, boat and gas. Sampling takes place weekly between June 1st and September 1st.

For more information about this program contact Amy Picotte, the VT LMP & Project WET Coordinator

• All LMP Lakes to Date (pdf, 43 KB)
• Current LMP Lakes Map (pdf 1 MB)
• LMP Lake Data
• LMP Manual (pdf, 300 KB)
• Vermont Volunteer Surface Water Quality Monitoring Guide

Updated: September 2004