FOXBORO - The Neponset Reservoir is coming up in the world - literally.

Treatment to reduce invasive species of weeds is under way, and the water level in the lake is being brought back up.

The reservoir has been treated twice with fluridone, the last time earlier this month, temporary conservation Chairman William Hocking said.

The drawdown of the reservoir was completed in early May, temporarily bringing the water level down 16 1/2 inches.

"Now the boards are back and it's filling up again," Hocking said. The NRRC Inc., a nonprofit citizen group working toward phosphorus remediation in the Neponset Reservoir, is conducting a three-year aquatic herbicide (fluridone) treatment of the reservoir.

This year's program involves a whole-lake herbicide treatment aimed at controlling excess populations of aquatic invasive species, principally fanwort, and also some less abundant populations of variable watermilfoil and curly leaf pondweed.

Fluridone prevents the production of the yellow carotinoid pigment which protect plants from overloads of light energy.

The plant eventually dies from "sunburn" when chlorophyll is destroyed.

Because the herbicide is so specific to plants, fluridone exhibits little, if any, toxicity to fish or aquatic invertebrates.

Regular in-lake monitoring of Neponset Reservoir will be conducted during the 60-day treatment period to verify fluridone concentrations and provide booster treatment, as needed.

In addition, if the occurrence of algal blooms are identified, then algaecide treatments maybe applied.

A post-treatment aquatic vegetation assessment will be conducted to quantify water quality improvements and help assess future lake management needs.

The lake drawdown was done to increase the effectiveness of the aquatic herbicide treatment.