BY DUSTIN PANGONIS
Fawn Lake is inspected annually and recommendations are made to the Association. The 2008 Annual Inspection Report had recommended a structural evaluation on the spillway walls, which the Association had scheduled to address. In the meantime, the spillway wall failed, and now improvements to the dam need to begin immediately. DEP’s Division of Dam Safety determined that the wall failure poses a threat to the structural integrity of the dam, and determined a drawdown of the lake was necessary to for the safety of the downstream residents. DEP ordered the dam to be drained and temporary stabilization to be constructed. This is to prevent the spillway from overtopping and potentially causing further damage or failure of the dam. DEP is also requiring the Association to perform an engineering evaluation and make any upgrades to the dam necessary to meet current standards. The dam was constructed in 1971 to the regulatory standards of that time, however the standards have changed and the dam may not meet current standards. It should be noted that Fawn Lake would have been mandated by DEP to perform this evaluation within the next few years, however, due to the wall failure, it has been deemed necessary at this time.
A contractor will be on-site constructing the temporary stabilization measures in the very near future. The slope will be tapered back and stabilized with slabs of the fallen wall and rock. Steel bracing will also be placed on top of the standing walls to avoid any future wall failures. This work was reviewed and approved by DEP Division of Dam Safety.
Upon completion of the temporary stabilization, the engineers will begin to evaluate the dam. Upon completion of the preliminary evaluation recommendation to address any deficiencies of the dam will be made to the Association. Upon concurrence of the preliminary analysis by the Association and DEP, final design of the improvements can begin. It is anticipated that Fawn Lake will remained drained until such time that the potential hazards created by the wall failure are addressed to the satisfaction of DEP Division of Dam Safety.
Photos: Fawn Lake Spillway Wall Failure
Frequently Asked Questions
Why does the dam need to be totally drained?
The dam is being drained to allow for maximum storage availability in the event of a significant storm. It will limit the possibility of further damage to the spillway or other areas of the dam. If a dam failure would occur, downstream properties and possibly the Lake Wynonah Dam and its downstream properties may be flooded causing damage of property and injury to people.
Why is Fawn Lake being drained for spillway repairs, while other lakes did not have to be drained to repair their dam?
Due to the wall failure, the structural integrity of the dam is compromised and necessitates the dam be drained to prevent loss of downstream life and property.
Why can’t the wall just be fixed?
Due to the extent of failure at the dam DEP Division of Dam Safety is requiring an extensive analysis of the dam to ensure that the structure meets current design standards. Repair of only the wall may be wasted effort if additional modifications to spillway are required.
Why is an analysis of the dam required?
As a dam owner, there is a responsibility to maintain the dam in a safe condition. From DEP’s Liability and Responsibility of Dam Owners Fact Sheet:
“The general rule is that a dam owner is responsible for the dam’s safety, and liable for damages caused by its failure. And, a dam owner is responsible for flood damage caused to upstream properties by the storage of floodwaters, as well as damage caused by the sudden release of stored water by failure of the dam or intentional rapid draining of the impoundment. The dam owner must do whatever is necessary to prevent injury to people or damage to property. This usually applies to foreseeable circumstances and situations, which can be anticipated with reasonable certainty.”
When will the repairs be done and the dam is filled to normal pool level?
We are currently completing the necessary temporary stabilization of the spillway approved by DEP Division of Dam Safety. DEP has also requested that a Hydrologic and Hydraulic Analysis/Alternatives Design report be prepared to identify any deficiencies with the dam. The results of this analysis will determine the extent of repairs required. A schedule to complete the repairs will be prepared at that time. It is anticipated that the dam will remain drained until all the necessary repairs are complete.
What will be done to save the aquatic wildlife?
The lake is being drained slowly to allow for aquatic wildlife to migrate to the deeper areas of the lake. The Fish Commission has been contacted and is working with your local fish and boating group to plan and relocate as much wildlife as possible.
Does DEP need to conduct a Pennsylvania Natural Diversity Inventory (PNDI) search to identify any endangered species prior to lowering the dam?
Due to the serious situation, their focus is on loss of life and property, therefore the drawdown was ordered by DEP Division of Dam Safety. A subsequent check of the PNDI database indicated no endangered species are present at Fawn Lake.
Are there any endangered species in Fawn Lake?
A PNDI search was completed by the engineer and 0 (zero) known impacts were identified.
How does this affect Lake Wynonah Dam?
Currently, the wall failure at Fawn Lake should not have any direct affect on Lake Wynonah as long as Fawn Lake remains drained. However, if Fawn Lake fails there is potential for Lake Wynonah to be damaged or fail as well.
What is being done to prevent this same thing from happening at Lake Wynonah?
Since both dams were constructed at the same time there is concern for the condition of the walls at Lake Wynonah. Concrete repairs are currently being made on the bridge and spillway to address known problems. Also, bracing is being considered for the spillway to prevent any wall movement.
How much will the repairs cost?
We are very early in the process of determining the necessary repairs to Fawn Lake. Without having completed the required engineering evaluation determining the cost of any repairs that may be required would be inappropriate at this time.
How are these repairs going to be paid for?
State and federal funding programs will be explored, although monies are not as readily available for private owners as they are for public owners. A special assessment may be imposed if alternative funding is not available.
BY DUSTIN PANGONIS
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