Page 56 of the April 2013 Lake Report indicates that drawdowns "will likely need be repeated every two to three years..." Is that true of both a one winter (short) and two winters (long) drawdown? Does a longer drawdown extend the time between future drawdowns?
The reference to the need for repeated drawdowns refer to over winter drawdowns for AIS control only. The over summer version is to be considered only to compress silt and increase water depth. We wouldn't consider an over summer drawdown more than once a decade, if even then. It's more of a one and done event. The over summer version would most likely increase the reduction of AIS vs the winter only drawdown and would likely postpone the need for a subsequent winter drawdown for AIS control.
I did not see any mention of shoreline erosion as a contributing factor tot he silt build-up. Is there a correlation? Are we monitoring shoreline erosion, especially on Lake D with its high wave action from wind and boat wakes?
This is a good question. It would be difficult to discriminatebetween silt from erosion and silt from dying plants. We might learn from bathymetry tests, measuring lake topography changes over time, by looking at Lake D changes vs the basins that don't allow skiing. If there is greater depth loss in D over time it might point to shoreline erosion vs plants dying. Most of us on D have our shorelines riprapped to protect them from the wave action so I'm guessing it would difficult to quantify. The greater concern from my perspective is the stirring of lake sediment on Lake D due to boat activity that brings nutrient laden silt to the surface causing increased plant growth. We see evidence of this in our lake chemistry measurements on Lake D.
What are the differences in effectiveness between a short drawdown and a long drawdown? Can it be quantified (or estimated) in terms of both aquatic plant and silt removal?
Based on data collected by other lakes that have done drawdowns an over winter drawdown would reduce AIS by up to 80% but do very little silt compression. The over summer version would compress silt by up to 3 feet if weather conditions are ideal, i.e., low rainfall, less if we have a wet summer. The increase in AIS reduction might exceed 80% but it would be as much from the two over winter periods that would be included with the summer drawdown. To be clear, we would get the dual benefit of silt compression and AIS control with the over summer version but this 18 month duration drawdown should only be considered for silt reduction. We can accomplish our AIS control goals with just the over winter version.
What if you do not want to vote for a drawdown, is there a third option to vote NO?
Do not cast a ballot or vote for any option. Given the people present at the meeting, the base number of votes will be known at the meeting. For any option to be chosen, it has to have a majority votes present at the meeting. If no one votes for any of the two options, then these NO votes will outnumber the YES votes. Upon review, this may be revised.
For the drawdown, would property owners be able to make shoreline repair to existing rip rap shores during the drawdown?
Yes...just check the DNR Shoreline regulations (NR115) to determine what you can or can't do legally to change your shoreline and work within the 75 foot zone originating from the high water mark on your shoreline. In additon, there are some Town Zoning Ordinances that may impact what you can do.
QUESTIONS 6-7-8-9 A number of comments and questions focused on these general general themes:
6) There are many people who don't want any drawdowns. I sure hope no one rams this drawdown through without a vote by all of the owners.
7) A lot of lakes have tried drawdown with no results. Where is the proof that this will benefit ouyr lakes?
8) A lot of us remember the last drawdown that the DNR provided when we were talked into replacing the dam. The only thing that did was ruin the fishing. There was no compaction of silt that is suggested...and it took seven years for the frogs to return.
9) The stated purpose is to partially kill weeds? For that we are to give up boating and swimming? Are you kidding? Suggest you ask the full population before you lower everybody's property value and lake recreation.
6) There will be no drawdown of the lake, partial or full, or any other action taken, unless voted by all the members on the lake at our Annual Meeting in July meeting of 2021. So far, that meeting is still scheduled. Details were in the postcard. Drawdowns will not happen unless there is a majority vote by the entire District to approve one or none of them. This will require that voters have to be physically present at the July 18 meeting. No proxy voting is allowed.
7) We were not talked into replacing the dam by the DNR... it was a District property owners' decision. A lake draw down was not part of our dam replacement plan then, nor was it suggested by the DNR. We chose to replace the dam ourselves because we were proactively thinking ahead. We recognized the dam’s warning signs, its failures in large rain storms, and that restoration had to be done while there were dam funds available to do it. If no plans had been drawn up to rebuild the dam, we would have missed the opportunity to fund our dam replacement.
8) Just as we had acted in the 1990's to recognize the failing signs of the dam, we are now recognizing the impact of expanding AIS as a failing condition of our lakes. We know that to do nothing will only make the lake worse in the upcoming years. Just as we acted to replace our failing dam, so too we are also looking at the current warning signs that say we must act in time and do something now to preserve the lakes.
9) Our consultant, Onterra LLC, has been studying our lake for many years. They are presenting us with scientific evidence that suggests that the lakes can be improved with the right actions. In addition, they have pointed out that these options will have a benign impact on the aquatic life and balance in the lakes. Please read all of the documents that are posted in this DRAWDOWN tab section to find out how that can happen.