Lake Projects

Weed Control | Lake Monitoring | Surveys

Weed Control
Aquatic plants found in Potter's Lake include muskgrass, coontail, common waterweed, water star grass, Eurasian watermilfoil, slender naid, nitella, white water lilly, curly leaf pondweed, sago pondweed, flat stem pondweed, and horned pondweed. Until recently, Eurasian watermilfoil and curly leaf pondweed dominated the vegetation. In 1975, the lake was chemically treated to remove all vegetation. From 1975 to 1997, the District maintained a harvesting program. In 1998, a selctive herbicide was applied to remove Eurasian watermilfoil from the lake and to promote the growth of native aquatic plants. Harvesting was not done in 1998 but is contemplated for future years, depending upon need and the ability to chemically “spot-treat” for milfoil should it return. To monitor progress, a plant survey is conducted annually.

-A weed harvester, conveyor and truck were purchased in 1976.

- Sanitary sewers were first installed in the District in 1977 and completed in 1981.

- The weed harvester was replaced in 1984.

- A second conveyor was purchased in 1986.

- The truck was replaced in 1992.

- Two new conveyers were purchased in 1995 as well.

- In 1996, the weed harvester was completely serviced and a new cutting head was installed.

- In 1997, the District sought and received DNR approval to use Sonar, a selective aquatic herbicide, to control the Eurasian watermilfoil in the lake and to promote the growth of native aquatic plants. The treatment was applied in October of that year. We continue to monitor results but every indication is a complete success -- the milfoil is reduced, the native plants are returning, and the fish population is increasing in number and size.

- To prevent the reseeding of the milfoil plant, the District installed slow/no-wake buoys in several sensitive areas of the lake. State law requires that boats stay 200 feet or more from all shoreline areas, piers, and navigational markers.

- During those years when harvesting is done, shoreline weeds are picked up by the weed harvester on the third Saturday of each month, June through September. Weed piles will be picked up at other times if the homeowner is available to assist loading the weeds onto the harvester.

- Weed piles should be placed in an accessible area, away from piers, boats, etc. Weed piles should also be free of any debris such as sticks, rocks, cans, etc. It is helpful if you place your weeds on an old piece of plywood. Keeping the weeds off the ground allows them to dry more quickly. The more dry the weeds are, the less the weight. The less the weight, the more the harvester can carry. That adds up to fewer trips and that saves us all time and money!

 

Lake Monitoring

- A depth staff, used to measure the lake level, was installed in 1992.
- Also in 1992, the District received a five-year Lake Management Planning Grant for a water quality study.
- In an effort to acquire more of the watershed area, the District sought control over several pieces of property owned by the Town of East Troy. Three properties were given to the District and a fourth, transfer of which was not allowed in the deed restrictions, was leased to the District for $1.00 a year on a renewable ten-year lease.

 

Surveys

Introduction
In June 2001, Aron & Associates conducted an aquatic plant survey on Potter's Lake. The survey was part of an ongoing study to document changes in the aquatic plant community of Potter's Lake. The information can be compared with past studies and may be used by future investigators to determine if the aquatic plant population is changing. The impact of various management techniques may be evaluated based on their respective impacts on the aquatic plants.

A preliminary survey of the lake was made by boat. An attempt was made to locate all plant communities on the lake by region. No plants samples were collected and preserved since all species found had been collected during previous surveys. The maximum rooting depth on Potter's Lake in 2001 was determined to be ten feet.

Results
A total of eight species were found during the survey. Four of the eight species were observed only during the general survey and include Water Star Grass (Heterantha dubia), Flat-stem Pondweed (Potamogeton zosteriformis), Eurasian Water Milfoil (Myriophyllum spicatum) and Cattail (Typha sp.). These three species were observed in a small channel along the southwest corner of the lake. Cattails were observed in all wetland areas. Of the species observed in the transect survey Musk Grass (Chara sp.) was found at all depths sampled. There has not been an increase in diversity in the aquatic plant population since the Sonar treatment.

The most abundant species at all depths include Muskgrass (Chara sp) and Sago Pondweed (Stuckenia Rectinata). Muskgrass declined in density from 2000 levels but increased in the number of sample points found. Sago Pondweed and Curly-leaf Pondweed declined in both density and number of sample points found.

Potter's Lake 2001 Aquatic Plant Species List

Scientific Name	Common Name
Chara sp.	Muskgrass
Heteranthra dubia (Jacq.) *	Water Star Grass
Myriophyllum spicatum L.*	Eurasian Water Milfoil
Nymphaea sp.	White Water Lily
Potamogeton crisRus L.	Curly-leaf Pondweed
P.zosterformis Fernald. *	Flat-stem Pondweed
Stuckenia pectinata	Sago Pondweed
Typha sp. *	Cattail

(* Only found in the general survey )

Summary
The Potter's Lake Protection and Rehabilitation District harvested intensively until 1997. Eurasian Water Milfoil
(M. spicatum) was the main plant targeted for control. A demonstration chemical treatment was conducted using Sonar in fall 1997. Since then, the harvester has not been used on Potter's Lake. Sporadic treatment for small patches of Eurasian Water Milfoil have been conducted in 2000 and 2001.

In general, the aquatic plant community of Potter's Lake has only fair diversity. It has not improved since the Sonar treatment. Eurasian Water Milfoil is beginning to appear in more areas around the lake. Spot treatments may cease to be effective in trying to eliminate Eurasian Water Milfoil. The District should begin to plan for another whole lake treatment in a few years as Eurasian Water Milfoil continues to expand its growth range in the lake.