A state-required engineering study has concluded that Orchard Lake Dam should be classified as a high-hazard dam, but Botetourt County officials emphasize that the finding does not mean the dam is in imminent danger of failing.
According to the county’s press release, the classification is based on what could happen downstream if the earthen dam were to fail. Engineers determined that three homes and nearby roads could be affected by floodwaters before they spread and diminish.
“High hazard” is a regulatory classification based on the potential consequences of a dam failure, rather than a finding about the dam’s current structural condition.
The study did, however, identify a significant issue with the existing structure. The county said in its press release that the dam’s spillway does not have sufficient capacity to meet the applicable state requirements for a high-hazard dam. If the dam remains in place, upgrades likely will be necessary.
The findings are the latest development in a dispute that has unfolded over several years involving the dam’s safety, ownership and the cost of bringing it into compliance with Virginia regulations.
Orchard Lake is a roughly 13.5-acre private lake in the Orchard Lake subdivision in Daleville. About 50 residences are located in the subdivision, while the lake is divided among 11 private properties.
The dam dates to the early 1900s, when it was built as an agricultural irrigation pond. The subdivision developed around the lake in the 1970s.
Botetourt County became involved after an engineer hired by the private dam owners discovered that part of the dam extended onto county-owned property.
The county eventually acknowledged ownership of a portion of the dam, making it responsible for complying with state dam-safety requirements along with the private owners.
In 2022, the Virginia Department of Conservation and Recreation (DCR) notified the dam’s owners that they needed to provide engineering and safety documents, including a professional inspection, emergency action plan and dam-break inundation study. The requirements also include regular inspections and maintenance.
According to the county’s history of the project, the private owners concluded that complying with the regulations would be difficult and expensive. Several options were discussed, including repairing the dam, lowering its height, or breaching it, which would drain Orchard Lake and restore the creek.
The private owners also expressed concerns about downstream safety, liability and the cost of maintaining a regulated dam. There was no agreement among lake property owners to form a homeowners association or otherwise share the cost of maintaining or repairing the dam.
By August 2024, the private owners and county staff had concluded that breaching the dam and draining the lake appeared to be the most viable option, given the projected costs, liability concerns and lack of a collective funding arrangement.
The county subsequently helped the private owners pursue a grant for engineering work associated with a potential breach and lake drainage. But the county did not ultimately commit to removing the dam.
Instead, the Board of Supervisors directed staff to examine alternatives, including repair, lowering the dam or breaching and removing it. The county later authorized Timmons Group to conduct the engineering work, including the Dam Break Inundation Zone, or DBIZ, analysis and an alternatives analysis.
When the contract was approved, county Capital Projects Manager Rich Evans said the dam was labeled high hazard on a presumptive basis, but that “nobody really knows that answer until the DBIZ study is completed.”
The completed study now provides that analysis. Timmons Group modeled several scenarios, including sudden failure under normal conditions and failures during major storms. The study concluded that the dam should be classified as high hazard because a failure could affect three downstream homes and nearby roads.
The county is not currently planning a separate interim action while the alternatives analysis is underway. Instead, officials say they are proceeding with the engineering review and required coordination with DCR.
According to the county, the alternatives analysis will examine the measures needed to address the spillway deficiency and bring the dam into compliance with state requirements. Timmons Group’s alternatives analysis is expected to be completed later this fall and will provide preliminary costs, timelines and engineering considerations for repair, lowering or removal.
Once the study is complete, the county will review its findings. Any significant decision regarding the future of the dam would involve the Board of Supervisors and a public process, according to the county.
The county said the purpose of the alternatives analysis is to fully evaluate the options before a determination is made.
For Orchard Lake residents, the completed DBIZ study provides a clearer picture of the potential consequences of a dam failure and what must be addressed to meet state requirements. The remaining question is which solution makes the most sense and what it will cost to implement.
~ Fincastle Herald staff report
