D. Survey Methodology- A Closer Look

The WDNR's Aquatic Plant Management In Wisconsin (4/25/05 draft) handbook was used as the survey protocol. Although the grant proposal suggested utilizing three volunteer boats, each using a two-person survey team, experimentation found that a three-person crew with one boat and/or pontoon was more efficient.. Consequently, the survey group worked as one unit/team to conduct the survey. Utilizing one group with knowledge and expertise proved to be faster, more accurate and safer. There was still ample opportunity for citizen involvement.

Methodology for gathering Tier 1 survey data:
Tier 1 survey lakes are the smaller seepage lakes that are in the Barnes/Highland areas. Because these lakes are small and some difficult to enter, smaller fishing type boats or canoes were used. One surveyor acted as the navigator and operated the craft in a "zig-zag" fashion through the littoral zone of the lake. The second surveyor would toss the grasping rake, gather and classify vegetation. The third surveyor would document the findings. Large colonies of plants were sketched on the lake map. The three surveyors would collaborate at times to classify any questionable aquatic plants. Plants in question would be taken to shore for classification. Plants were also "pressed" in an effort to create a collection of local aquatic plants for future reference. Lake maps with sketched colonies and listing of all aquatic plants for each Tier 1 lake were filed

Methodology for gathering Tier 2 data:
Tier 2 survey lakes are the eleven lakes that make up the Eau Claire chain plus Tomahawk and Sandbar Lakes the two infested lakes. Volunteer pontoon boats were used for the survey and oftentimes the owners helped with the operations. The Tier 2 survey was more involved and sophisticated. The DNR (Jennifer Hauxwell/ Daryl Ridgely - see Contacts in Appendix 7) e-mailed a large number of sampling points for each lake. These sampling points were uploaded on the Global Positioning System (GPS) unit (Garmin GPSMAP 76S) via the computer.

Sampling points were pre-determined by the WDNR utilizing a formula (see survey protocol) based on the littoral zone of the lake, lake surface area and shoreline length. Bathymetric lake depth survey maps were also downloaded and used to determine the littoral zone where most of the aquatic plants would be present. With this instrumentation and information in place the survey proceeded.

The GPS points identify the precise location of latitude and longitude (lat/long) and are accurate to within about 9 feet. These points are overlaid on the lake map in a grid pattern along transects which follow the cardinal directions. This allows for a relatively easy procedure to locate the sample points in a consecutive numbered order.

The methods used in establishing sample point locations created different sample frequency for each lake. The thirteen lakes sampled with this method had sample point frequencies that ranged from Smith Lake that had 143 point on 31 acres (.217 acres/point) the highest frequency to Middle Eau Claire Lake where each sample point represented 1.14 acres. On average the sample frequency was slightly under 1 acre per sample point. See Table 4 for a summary of sampling data.

Sampling was completed on GPS points that were in the littoral zone (under 20 feet in depth) A depth sounder was used to insure the point was less than 20 feet.

Additional Resources

Essentials for the Field (on the water) Survey Team

Essentials for Office/Lab Work for Survey Team

Table 4 Aquatic Plant Survey Data Summary