Tim Hoyman's Lake Study Presentation
Highlights
Saturday, October 24, 2009
* It is impossible to adequately summarize the results of a two-year study on the website, but here are a few of the highlights.
[Tim Hoyman knows the person who did our last professional study and is familiar with his work]
1) We have a healthy lake and good fish habitat. Steady management should prevent it from degrading, though it is natural for phosphorus, chlorophyll, and water quality numbers to fluctuate up and down over the years.
2) Phosphorus is the component that most affects the fertility of our lake. An insignificant amount (162 lbs.) comes from our watershed. The most effective way of reducing phosphorus is to return all lakefront properties to a natural state. While rocks are attractive on the waterfront, they do not filter water runoff, and are therefore not good choices if you intend to help protect the lake from phosphorus.
3) All lakes fill in and become fertile, meaning they become increasingly more productive in not just growing weeds and algae, but collecting muck, as well. The process takes thousands of years, not decades; man's influence speeds it up.
4) Though some fluctuation has occurred, levels of phosphorus, chlorophyll and water clarity have been stable, at least since the 1970's, when records were started. These results are probably due to the modernization of our septic systems, which are not a problem at this time. Using our two previous professional lake studies as a reference (1976 & 1992), amounts phosphorus, chlorophyll have decreased and water clarity has improved.
5) 484 separate places on our lake were examined with raked samples to identify aquatic plants and sediment from the lake bottom. GPS technology allowed the testers to cover the entire lake in evenly-spaced segments.
6) Most of the phosphorus in our lake comes from "internal loading", which is fertile sediment that gets stirred up through wind and wave action. The shallowness of our lake magnifies the phosphorus problem.
7) Curly-leaf Pondweed is one of two NON-NATIVE plants which are present in various areas of our lake and, in some places, is the dominant strain. Since the 1970's, it has spread but is not threatening to take over the lake. For the time being, our strong and abundant NATIVE plants are keeping Curly-Leaf from growing wildly. We must, however, carefully monitor this plant and be sure its' influence does not increase greatly as it could be a way to make our lake much more fertile - quickly. This plant is most visible just after the ice goes out and recedes in July. Its' decay during the summer helps our other weeds grow faster. The leaves of this plant have a "twisted" look to them. The plant gives off "turions" during the summer which are seeds for new plants. These "turions" resemble little pine cones with a "screw-like" appearance. They are shaped somewhat like drywall screw anchors and are dark brown in color. If noticed on your beach, carefully pull out the plant and roots. Remove and dispose of the "turions", which sometimes float.
8) Eurasian Water Milfoil (EWM) is the other NON-NATIVE plant in our lake. Thankfully, it is confined to one place near our main boat launch in the channel (north) approximately 35 yards from the pier. Tim Hoyman and his team have checked the area two times a year since our study began in 2008, but we need a group of volunteers to receive DNR training so we can maintain a close watch on the lake. If we intend to prevent the invasive plant from spreading and taking over, we must root it out as soon as it appears. Left unchecked, EWM forms a heavy mat on the waters' surface and chokes out everything under it.
9) We have 28 NATIVE plant species in our lake, a good, diverse number; more than we had in the 1970's. Four of those plants are far and away more numerous than the others. Those plants are: Coontail, Flat-stem Pondweed, Common Pondweed (Elodea), and Fern Pondweed. Two of those four form floating masses.
10) Our best defense for invasive species is to maintain strong NATIVE plants.
11) Cutting aquatic plants, as we have been doing since 2005, does not weaken the NATIVE plants at all.
12) Plant harvesting, as we have been doing it, on a limited basis, is the BEST way to manage our aquatic plants.
13) As for our fishery, the last DNR survey was done in 1975; another is scheduled for 2010. Tim recommends our that our residents contact the DNR to press our interest in order to avoid possible delays due to budget constraints. When a survey is done, crews actually shock areas of the lake and count the fish and the different species. In this process, using a statistical analysis, fish biologists can determine a fairly accurate profile of our fishery.
14) Regarding the Stakeholder Survey, 55% responded, a reasonable number. Fifty-six percent of the residents (families) have owned lake property for ten years or less. Comparatively speaking, other lakes show a lower percent with more owning their lake property for several decades. The survey showed three top concerns: 1) excessive aquatic plant growth, 2) water quality degradation/pollution, 3) algae blooms.
15) 86% of our respondents favor weed cutting to reduce the weeds.
16) Water clarity on our lake is acceptable, though it varies throughout the year, and has improved over several decades.
17) Algae blooms are common in EUTROPHIC systems with good water quality. Tim recommended Jim Kreitlow in the Rhinelander DNR service center to help us identify and learn more about the specific algae we have on our lake. Algae is a natural phenomena on lakes.
18) Keeping our water level where it is, neither at its' highest nor lowest level, is best for the lake, given lake users need to recreate and use the lake for fishing, swimming, boating, & water skiing. We should keep the same number of boards in the dam throughout the year, season after season. Lakes adjust to water levels, so changing them repeatedly is not good for the eco-system. In a natural state, lakes drop during the summer when it is dry and fill back up in spring and fall after snow melts and rain.
19) Dredging our lake just a yard, even only a few acres, would cost millions of dollars and open the lake to invasive species colonization. So dredging is not a feasible solution to the sediment in our lake.
20) Our DNR mechanical plant harvest map allows 144 acres of our 367 acres to be cut. According to DNR rules, we may choose 75 acres or less to harvest per year. In 2009, we harvested 59 acres.
21) Using GPS technology, we can mark our weed-cut grid (map) and locate year to year where the weeds actually are. That grid can be digitized by Tim Hoyman's group and given to Cliff Schmidt, our weed harvester, for precise cutting in just those areas. The equipment Cliff has allows him to leave one cut path and return, within inches, when the next strip is cut.
Implementation Plan
MANAGEMENT GOAL 1: Understand and Maintain Water Quality in Horsehead Lake
Management Action #1: Continue collecting water quality data on Horsehead Lake as a part of the DNR Citizens Lake Monitoring Network.
Facilitator/s: Dennis and Kris Batchelet
Funding: Funded through DNR program
Management Action #2: Reduce phosphorus and sediment loads from immediate watershed.
Facilitator/s: ? [this role needs to be filled]
Funding: DNR Small-scale Lake Management Planning Grant, Aquatic Invasive Species- Education, Prevention, and Planning Grant
Management Action #3: Gain and understanding of filamentous algae with Horsehead Lake beginning in 2010.
MANAGEMENT GOAL 2: Control and Prevent Aquatic Invasive Species within Horsehead Lake
Management Action #1: Monitor and control Eurasian Water Milfoil within Horsehead Lake beginning in 2010.
Facilitator/s: ? [this role needs to be filled]
Funding: DNR Small-scale Lake Management Planning Grant, Aquatic Invasive Species -Education, Prevention, and Planning Grant
Management Action #2: Monitor Curly-Leaf Pondweed within Horsehead Lake; 2009-'10.
Facilitators: Horsehead Lake Board of Commissioners
Funding: DNR Small-scale Lake Management Planning Grant, Aquatic Invasive Species- Education, Prevention, and Planning Grant
MANAGEMENT GOAL 3: Maintain Navigation in Open Water and Near-shore Areas on Horsehead Lake
Management Action #1: Use contracted harvesting services to maintain reasonable navigation on Horsehead Lake
Timeframe: Ongoing
Facilitator/s: Horsehead Lake Board of Commissioners
Funding: DNR Small-scale Lake Management Planning Grant, Aquatic Invasive Species -Education, Prevention, and Planning Grant (GPS purchase and training)
Action Steps:
1) Volunteers survey lake and mark quarter-acre squares on map grid for harvesting
2) Squares tallied and sum acreage of that year's harvesting calculated
3) Harvesting map and estimated acreage are provided to DNR 14 days prior to expected harvesting dates