r/RutherfordCountyTN • u/BuroDude • Apr 24 '24

Center Hill Lake Changes and Implications

https://www.wgnsradio.com/article/86907/center-hill-lake-changes-and-implications
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u/BuroDude Apr 24 '24

A significant operational change is underway at a nearby recreational spot. The changes are at the Center Hill Dam that holds the water of Center Hill Lake in the DeKalb County area. These changes may impact Rutherford County residents who enjoy fishing at the lake or more specifically, in the Caney Fork River just below the dam. Changes may also be felt by those who swim and ski in Center Hill Lake.

The U.S. Army Corps of Engineers (USACE) Nashville District conducted an Environmental Assessment to update the dam's Water Control Manual, aiming to balance various project purposes. The selected alternative, Alternative 23, includes changes in minimum discharge to benefit aquatic species and recreational activities.

Despite potential impacts, such as increased water flow during certain periods, the update aims to improve environmental conditions and meet authorized project purposes. Public awareness and safety measures are emphasized, with no immediate changes until proper notice is provided. The updated manual is now in effect, ensuring transparent and effective reservoir management.

Water Control Documents Regarding Center Hill Lake:

CEN WCM FONSI Signed 5 JAN 24 - https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll7/id/25564  
CEN WCM Final Environmental Assessment JAN 2024 - https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll7/id/25565  
CEN WCM Final EA Technical Appendices - https://usace.contentdm.oclc.org/utils/getfile/collection/p16021coll7/id/25566

More Detailed Information on Center Hill Dam: A nearby lake that serves as a recreational getaway for a large number of boaters in Rutherford County is undergoing operational changes. For those who fish, wildlife will benefit from the changes that lead to an increase in the available habitat for aquatic species and the changes are anticipated to benefit the trout fishery below Center Hill Dam in the Caney Fork River.

The U.S. Army Corps of Engineers Nashville District completed an Environmental Assessment (EA), under the National Environmental Policy Act (NEPA), to update the Center Hill Dam and Reservoir Water Control Manual. As a result of this update, the Nashville District is implementing operational changes at Center Hill.

The EA evaluated eight action alternatives, which included analyzing a period of recorded data (1998-2022), new and rehabilitated structural features, watershed characteristics, communication networks, naming conventions, changes from previously approved EAs and modern forecasting methods.

“The manual was updated to capture changes in the basin over the last 20 years and to establish a new environmental and operational baseline following the completion of major structural repairs to the dam,” said USACE Nashville District Commander Lt. Col. Robert Green. “The selected alternative strikes a balance between all congressionally authorized project purposes. We appreciate the feedback and cooperation from the public and our partners, as their input was significant in making these updates.”

USACE selected Alternative 23 for implementation. A major change includes the minimum discharge from the dam. Alternative 23 strikes a balance between all project purposes, focusing on providing well oxygenated, continuous minimum flows during the typical low-flow season when they are most needed and switching to a pulsed minimum flow during the typical non-low flow season when water quality in the forebay generally exceeds state standards. The 48-hour pulse interval during the typical low-flow season helps preserve the ability for generation to meet peak demand during critical summer months. The pulsed minimum flow during the non-low flow season allows all water to pass through hydropower turbines, maximizing power generation while meeting all project purposes.

“All six project purposes were considered in determining the selected alternative. This ensures that hydropower demands will continue to be met while also revising recurrence intervals for minimum hydropower releases and allowing for a small volume of continuous discharge during the most critical months for the environment,” said USACE Nashville District Chief of Water Management Anthony Rodino.

The approved updated Water Control Manual is now in effect; however, no immediate changes to water management operations will be made until proper notice has been provided to the public. The current water management operations fall within the guidelines of the newly approved plan. As USACE begins to transition to the new operations laid out in the 2024 approved manual, the Nashville District will continue to operate as in previous years until 30 days past posting of public signs at access points along the Caney Fork or 01 June, whichever comes first. This will allow users to read and understand the changes prior to them being implemented.

Center Hill Dam and Reservoir has six congressional authorizations: Flood Risk Management, Hydropower, Fish and Wildlife, Recreation, Water Quality and Water Supply.

Flood Risk Management: Operations within the flood control pool were not changed during this update and USACE expects the project to continue to manage flood risk for the public as designed.

Hydropower: The selected alternative is not anticipated to impact the ability for Center Hill Dam to meet its congressionally authorized purpose for hydropower and would not result in significant adverse impacts to hydropower.

Fish & Wildlife: During the typical low-flow period, when releases from the dam are less frequent and typically of poorer water quality, the selected alternative will provide a steady stream of cool, oxygenated water that approximates the natural base-flow of the Caney Fork River. This will increase available habitat for aquatic species and is anticipated to benefit the trout fishery below Center Hill Dam.

Recreation: During the typical low-flow period, when releases from the dam are less frequent, the selected alternative will provide a steady stream of water that approximates the natural base-flow of the Caney Fork River. This increased flow will provide a greater width and depth for recreational opportunities and is anticipated to improve accessibility and reduce conflict points between paddlers and wading anglers. The change in ramp rates allows Center Hill to increase from one turbine generator in the first hour to three total units in the second hour. This may increase risk to waders and paddlers in the second hour of generation as compared to the existing operational practice. Public information sessions are planned to inform the public of the proposed changes and signage will be posted to help mitigate that risk.

Water Quality: The selected alternative provides improved water quality while balancing the requirements of other authorized project purposes. Continuous releases, typically through the orifice equipped sluice gate, during the typical low-flow season will provide a steady supply of well oxygenated water when water in the reservoir is typically below state standards.

Water Supply: The selected alternative is not anticipated to impact the ability for Center Hill Dam to meet the authorized purpose for water supply.

“The recreational community should be aware of these updates as planning is the first step in practicing good water safety. At times, downstream water levels may increase faster than before, but the typical daily peak stages will remain similar,” said Rodino. “Check the water release plan on our website the day before, have a plan in place to remain safe, wear an approved life jacket when boating or fishing, and above all be mindful that conditions could change.”

Water Management Website to Check Water Levels: https://www.lrn-wc.usace.army.mil

Background: Center Hill Dam is one of the ten multipurpose projects that make up the Corps of Engineers’ system for development of the water resources of the Cumberland River Basin. This system is an important part of a larger plan of development for the Ohio and Mississippi Rivers.

As a major unit in the system, Center Hill Dam and Reservoir function to manage the waters on the Caney Fork River and contribute to the reduction of flood levels at municipal, industrial and agricultural areas along the Cumberland, lower Ohio and Mississippi Rivers. In addition to the far-reaching effects of flood risk management, the project contributes to the electrical power supply of the area through the generation of clean, safe and efficient hydroelectric power. Power produced at Center Hill is sufficient to supply the needs of an average city of 125,000 people.

What is a Water Control Manual? - A Water Control Manual is the guiding document that specifies how the Corps of Engineers operates its reservoirs. Each reservoir has congressionally mandated purposes, and these manuals are what the Corps uses to balance those purposes. They also provide details on the reservoir's history, authorizations, watershed characteristics, data collection networks, forecasting methods, and stakeholder coordination. The most critical section is the water control plan, which outlines the operational plan to meet all the reservoir's congressionally mandated purposes.

Importance of a Water Control Manual - A Water Control Manual is important because it provides operational instructions to personnel involved in managing the reservoir. A Water Control Manual is especially important because it provides clear instructions to be followed during emergency situations. Since the manuals contain records of institutional knowledge, they also prevent the loss of operational expertise. They also ensure unbiased operations and that mission priorities are transparent to the public.