As we work through the Special Assessment for the operations and maintenance of the dams, we've received questions about how the dams will operate and what benefit they bring. Below is a brief explanation with links to articles published in the past that explain these concepts.
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The dams will be operated as "run of the river" facilities. This means the dam gates are operated to keep a normal "legal" lake level, such that the outflow from the dam is equal to the water flowing into it. The dams will not store additional water in the lake, therefore the lake levels will not fluctuate as much as they did when the dams produced power. The lake level is more stable and downstream of the dam, the river will be a natural flow, with less negative impact on the shoreline.
How the Restored Dams Will Operate in Large Storms
The dams were not built or used for flood control for large storms. We still get a few questions challenging this point, primarily with the view that property owners downstream should pay for the benefit of "flood control dams." Regardless of these theories being brought forward, the future use of the restored dams will not be for flood control, nor is there significant capacity in the Four Lakes system to build flood control dams that would justify the investment.
While the dams will not control floods for the downstream communities, the dams will be built to withstand major flooding. FLTF will provide the U.S. Army Corps of Engineers and EGLE with flow rates later this year for the flood studies downstream of the Four Lakes system. In addition, there will be extensive analysis on each of the dams as they are designed to ensure they can safely be rebuilt.
GEI Consultants completed the Semi-Quantitative Risk Analysis (SQRA) process for the northern two dams, which resulted in a recommended inflow design flood (IDF) for both dams. The recommendation will allow the dams to safely pass a 10,000-year storm event, which corresponds to a 1 in 10,000-year Annual Exceedance Probability (0.01% AEP). AEP is the chance or probability of a natural hazard event (usually a rainfall or flooding event) occurring annually and is usually expressed as a percentage. It should be noted that the May 2020 floods for the Secord and Smallwood dams were estimated to be between the 100- to 200-year flood (1% to 0.5% AEP).
Secord Dam: The 60% design spillway for Secord was sized to safely pass the IDF of 17,515 cubic feet per second (cfs). The current Secord Dam gate spillway discharge capacity is approximately 7,740 cfs.
Smallwood Dam: The Smallwood 60% design spillway was sized for an IDF of 25,500 cfs. The current Smallwood Dam gate spillway discharge capacity is approximately 10,145 cfs.
Overall, dam safety will be improved by significantly increasing spillway capacity from what historically existed.
Click the button to read more about the IDF selection approach.
Secord, Smallwood, Edenville, Tobacco and Sanford dams were built in the 1920s for the purpose of hydroelectric power generation, with the additional benefit of recreation. The dams are now being repaired and restored to return the lakes to their normal legal levels which will restore the benefits of a healthy ecosystem and recreational uses of the bodies of water. This provides economic benefit to the region as well as a lifestyle enhancement, all improving the quality of life in the region.
We believe the counties to have the dams restored, and according to the public survey conducted by PSC, 74% of property owners believe the costs should be shared with people outside of the Special Assessment District. The counties, by law, may determine to contribute to a portion of maintaining the normal legal lake levels by paying out of their general funds. If the counties approve the at-large assessment, it will be because they agree that there is an economic and tax benefit to their county. There will NOT be assessments to property owners outside of the Four Lakes Special Assessment District.
Interim Financing Update
FLTF previously documented in its Restoration Plan that an additional $10 million of funding in 2022 would be needed to stay on our plan. While we anticipate the state legislation will pass and provide significant funding to restore the lakes, FLTF is pursuing $10 million in a Grant Anticipation Note to bridge until we get state funds so we can stay on our current timelines for the stabilization of the dams.
While we hope the note is not needed, we will continue to pursue this interim path until the state funding is passed by the Michigan House and signed by the Governor.
Days of Review Bring Clarity to Property Owners
On January 15th and 17th, we hosted two of four Preliminary Days of Review. During these periods 138 property owners met with Spicer engineers and FLTF board members to discuss their parcel benefit factors. This was a successful event and engineers were able to refine the SAD based on the feedback they received.
If you cannot make it to the Days of Review but would like to have an engineer review your parcel's benefit factors, please fill out the form on this page.
Next Days of Review:
Tuesday, April 19, 2022 | 9 a.m. – 4 p.m. at Jerome Township Hall Wednesday, April 20, 2022 | 4:30 p.m. – 9:30 p.m. at Secord Township Hall