At the WWMD Monthly meeting on July 28th 2016, it was decided to not implement a drawdown for the 2016-17 season. The permit application has taken longer than expected and we are getting too close to the end of the season. We will continue working with Racine County and the WDNR to obtain the permit, and, if successful, will have the drawdown no earlier then the 2017-18 season. This will allow enough time for proper communications and for residents to apply for individual permits for riprap repair and removal of silt along their shoreline.
The information below discusses the possible benefits of a winter drawndown, possible disadvantages, and the work done in 2016 that has gone into considering a drawdown.
One technique that is available to help manage aquatic plant growth, especially Aquatic Invasive Species (AIS), is called an Over Winter Drawdown. This calls for slowly lowering the water level starting the middle of September. The level would come down approximately 3-4” a day until the level is decreased 4-5 ft. This level would be maintained over the winter and would be refilled in the Spring. Fill would start in March and should be complete by the end of May.
During the drawdown over 90% of the areas where we have invasive species growing would be exposed to the freezing and snow. This would kill the root systems so they do not return in subsequent seasons.
Feedback from other lakes where this technique has been used and from the WDNR shows close to 100% effectiveness the season after the drawdown. AIS slowly returns in the following years.
Advantages of this technique include:
- Large areas of AIS are removed from the waterway allowing natural and more diverse growth to return.
- Low cost. We currently spend $70,000 – $80,000 annually on herbicidal treatments.
- We greatly reduce the amount of herbicides we put in the waterway.
- During the drawdown individual homeowners have easy access to their shore walls allowing for repairs/replacement.
- During the drawdown individual homeowners or groups of residents in shallow areas can remove silt more easily in their areas. Permit may be required.
- In the shallow areas, exposed silt will be dried and compacted over the winter. This will provide some much needed extra depth for some.
As with most things there are drawbacks to this approach.
- The boating season is cut short.
- Impact to winter fishing and hunting activities.
Another area of concern that has been brought to our attention is the possibility of fish kills as a result of the drawdown. Although there is a possibility of a small number of fish being trapped, our waterway has enough deep water areas for the fish to move to.
The reason for the slow drawdown, starting in Mid-September is to allow wild life (fish, reptiles, amphibians) to move to safe areas as the water is lowered. The attached maps show the areas that will still contain water with a 5ft drawdown. Clearly Tichigan has sufficient water depth to support the fish. One miss-leading aspect of the maps is that the river channel will be dry. This will not be the case as the river will continue to run during the drawdown. We have several million gallons of water enter and leave our system each day and this cuts a channel through the water way. Similarly, as water drains from Tichigan, a channel will be maintained from the lake to allow the fish to enter.
- The WDNR will host a meeting in August as part of the permit application. Details on this meeting will be sent to all riparian owners.
Informational Meeting 7-12-2016:
Permit Application with WDNR
The links below show studies from other lakes that have had a drawdown.
Click here for a map showing areas exposed exposed with a 5 ft drawdown. The area down the river is an approximation of how the channel will be cut with the water flow.
1) What is going to happen?
a. The water level in the Waterford Waterway is proposed to be drawn down four to five feet, as measured at the face of the dam. For much of the waterway, a channel for the Fox River will be left. Within Tichigan Lake proper there will be less of an impact because of increased depth. The final drawdown depth will be determined as the drawdown progresses based on the ability to keep Tichigan Lake proper connected to the rest of the waterway to allow passage for fish and other aquatic organisms.
2) Why is this happening?
a. To reduce the extent of aquatic invasive species (primarily Eurasian water-milfoil) in shallow areas by exposing them to freezing conditions as a control option outside of repeated herbicide applications and to alleviate navigational nuisance in these areas caused by the dense plant growth. Additionally, some native plants can reestablish themselves as fluctuating water levels mimic natural processes. This can cause germination of seed banks present in sediment, increasing native plant diversity.
As a secondary effect, some areas may see some compaction and decomposition of soft sediment, or muck, leading to a small increase in depth (up to 6 inches) when refilled. The main channel areas should offer substantial head cutting due to increased flow offering the potential for additional depths of up to 1 – 2 feet in main channel areas after refill.
3) When is this happening?
a. The drawdown is proposed to begin on Monday September 19, 2016 at a rate of 3 – 4 inches per day until final depth is met, likely around October 3 – 10, 2016. Once at final depth, it will continue at that level, baring any major storm events, throughout the winter to be filled by the end of April, 2017.
4) Who is responsible for the drawdown?
a. The drawdown is being requested by the Waterford Waterway Management District, the dam is owned by Racine County, and the WDNR is responsible for issuing the permit and holding any hearings regarding the permit request. The Districts consultant is Wisconsin Lake and Pond and Resource.
5) What will access be like when drawn down?
a. Due to the shallow water within the river channel, access from both the Town ramp on the south and DNR ramp on the north will be limited to small, carry in only craft during the drawdown. Private access points on Tichigan Lake proper for ice fishing should see no affect due to the drawdown.
6) How will this impact the fish?
a. A slow, controlled systematic drawdown of 3”-4” per day will allow fish, amphibians, reptiles, and other aquatic organisms to move freely to deeper areas as water level recedes. Tichigan Lake proper will continue to have ample water volume to be a refuge for fish to move into. Some fish may move up or downstream into the river as well.
7) How will this impact the river downstream of the dam?
a. During the drawdown, normal flows will be maintained, typically equal to that during this time of the year at full pool, with little to no impact anticipated to the area below the dam gates. However, it is likely that no water is will go over the spillway on the eastern arm of the dam structure, which will be the only anticipated change downstream.
8) What will the waterway look like next year?
a. When refilled, the waterway will be much the same as in years past. There will likely be better boat access and navigation through the shallow bays due to some sediment compaction and lesser numbers of aquatic invasive species and overall vegetation.
Additionally, access from the DNR launch to north through Conservancy Bay will become easier as the drawdown will likely offer substantial channel head cutting and increase the depth through the delta area that is currently shallow and filled with sediment. This channel will be mapped with GPS when drawdown so channel markers can be placed there upon refill.
9) How long will the positive effects of the drawdown last?
a. Typically the reduction in aquatic plants, increase in species diversity, and reduction of sedimentation in shallow areas off the main channel and back bays should last at least 2 years and sometimes 3 years, possibly more. Each system is different in how it responds and it is based on the type of winter weather conditions present during the drawdown period. The increased main channel depth in Conservancy Bay and throughout the reservoir should last substantially longer.
10) Who can I contact for further information?
a. You can contact the Waterford Waterway Management District at 312-952-1959 /firstname.lastname@example.org. In addition, you can contact Craig Helker at the WDNR (262) 884-2357 / email@example.com or Mark Kordus at Wisconsin Lake and Pond Resource (715) 781-9976 / firstname.lastname@example.org.