Rapidan Fish Passage Project FAQs

RFPP is a long-term project to restore fish passage at Rapidan, Orange and Culpeper Counties, Virginia through alteration of the Rapidan Mill Dam (RMD) including upstream and downstream river stabilization and restoration.

The RFPP will reopen 531-1,000 miles (depending on metric used) of fish habitat in the Rapidan River and Robinson River watersheds of Central Virginia. Project design and engineering is focused on the migratory needs of River Herring and American Shad, as well as American Eel and Sea Lamprey. Reconnecting resident fish populations is an additional goal.  Restoration of fish passage at the Village of Rapidan, Virginia is the highest priority project of its type in the entire Chesapeake Bay watershed.

For roughly 250 years, migratory fish have been blocked from their historical spawning grounds upstream of Rapidan, Virginia by the RMD. This loss of habitat is part of the reason Atlantic anadromous and catadromous fish species have cratered since the dam was constructed.

Anticipated benefits include:

• Reconnection of headwaters spawning grounds to the ocean.
• Increased fish populations.
• Increased fish dependent wildlife populations.
• Increased filter feeding macroinvertebrates, mussels, and migratory egg carriers.
• Restoration of mile-long stagnant impoundment above the dam to natural free flowing river.
• Reduced flooding potential upstream of the dam while not increasing flooding potential downstream.
• Documentation of historic value of RMD and preservation of portion(s) of the dam while still an intact structure.
• Exposure of likely bedrock outcrops above the dam.
• Increased safety for recreational passage through Rapidan.
• National attention on the beauty and natural history of Rapidan River.

The existing ladder is in disrepair. However, its design will not work for RFPP target species because it is very steep and is designed for fish that can jump, like Salmon. Other anadromous fish, like American Shad, do not jump like Salmon and need lower gradients to get upriver. These targeted fish also school when they migrate and so need wide spaces as they swim upstream, not a narrow ladder.

The earliest work conducted to research options for restoring fish passage began in 2020 and continues today by the RFPP project team, with the list narrowing over time as options are ruled out for various reasons. Prioritized criteria for the right solution are for it to be effective in meeting the project’s goals for the targeted fish, lawful and respectful of historic and cultural resources, safe, sustainable, and not dependent on costly maintenance over time.

• New fish ladder
• Rock ramp
• Under Mill chute
• Fish friendly hydropower - https://www.natelenergy.com/
• Alteration of dam (partial removal)
• Alteration of dam (total removal)
• Alteration of dam (notch)
• No build (do nothing)

While dam alteration or removal has many benefits, such as restoring ecosystems, improving fish migration, and eliminating safety hazards, it can come with risks including:

A. Sediment Release & Water Quality Issues

Risk: When a dam is altered, trapped sediments can be released downstream. The amount and type of sediment varies by stream valley and upstream land uses. The amount of sediment that may be released downstream also depends on a variety of parameters. Some systems can tolerate released sediment while others may be sensitive to an increase or spike in sediment loads. Depending on the historical land uses some sediments may contain heavy metals, nutrients, or other contaminants potentially harming water quality and aquatic life.

Mitigation: Conduct sediment studies before removal, gradually release sediment, stabilize the sediments in place, or dredge and dispose of contaminated materials safely. Note that preliminary sediment studies around the Rapidan Dam found that the sediment was "clean" (contaminants below Maximum Contaminant Levels), with the exception of Vanadium, a naturally occurring element in area bedrock, according to a Professional Geologist hired by ACP to review findings. Also noteworthy is another preliminary study completed on sediment quantity, finding the existence of a small wedge only. 

B. Habitat Disruptions & Species Impact

Risk: While long-term habitat restoration is a goal, short-term disruptions can harm aquatic species, especially those adapted to reservoirs. RMD however due to its shallow depth has poor conditions for reservoir-adapted species.

Mitigation: None needed.

C. Infrastructure & Property Damage

Risk: Changes in river flow could erode riverbanks, potentially damaging infrastructure like bridges and roads or adjacent structures/buildings.

Mitigation: Conduct hydrological/hydraulic studies, reinforce or modify nearby infrastructure, and implement erosion control measures.  Note that RMD is not a flood control structure and in fact in its current configuration, during flood events RMD can locally increase flooding impacts. Part of the hydrologic/hydrualic studies will be done to predict flooding reduction.

D. Cultural & Historical Loss

Risk: Some dams have historical significance or hold cultural value for local communities.

Mitigation: Document and mitigate loss of historic resources. Studies have been initiated for the RMD regarding historical/cultural resources.

E. Invasive Plant Species

Risk: While many ecosystems recover well after dam alterations or removal, some may take longer, and invasive plant species can take advantage of newly exposed land.

Mitigation: Implement active restoration projects, including replanting native vegetation in any newly exposed banks, monitoring biodiversity, and managing invasive plant species. Some invasive plant species may have already been established in a restored area leaving mitigation unnecessary but still may be beneficial.

F. Legal & Regulatory Challenges

Risk: Permitting and regulatory hurdles, including opposition from stakeholders, can delay or complicate dam alteration or removal efforts.

Mitigation: Engage communities early in the process, ensure regulatory compliance, and work with multiple stakeholders to address concerns collaboratively.

G. Lowering of nearby water table

Risk: Depending on the dam configuration/height, groundwater table elevation versus stream bed elevation, and valley shape, dam alteration or removal can have the effect of lowering a nearby water table. The water column directly behind the RMD is roughly 10-11 feet tall diminishing to zero (0) feet roughly a mile back from the dam. Emptying this water column could cause the water table to drop an equivalent amount locally.

Mitigation: Model the potential effects of the RMD alteration or removal on the local water table to determine if mitigation measures are necessary. Possible potable well replacement if water level drops below existing  pumps or significantly reduces storage. Note that linear extent of area area potentially influenced by the river water table is likely small – perhaps a few hundred yards depending on geology.

H. Change of scenic quality

Risk: The dam in its current configuration can certainly be appealing. Alteration will change the scenic view and could potentially reduce the aesthetic.

Mitigation: Leaving portion(s) of the dam in place could retain some of the historical view shed. Note that the sounds and appearance of water moving over bedrock and potentially creating rapids have auditory and visual appeal thus actually increasing scenic quality.

I. Recreational passage impacts at Rapidan

Risk: None. There is currently no passage at Rapidan. No risk expected. Some risk exists now for paddlers, boaters, anglers, wildlife watchers, etc., that are recreating near the RMD. Altering or removing the dam is part of the mitigation to remove the current risk that is the dam.

Mitigation: None needed. Dam alteration can only improve passage.

J. Riverbank erosion

Risk: The shoreline will change above the dam and may change some below the dam due to the change in water elevations and stream flow velocities post dam alteration/removal. This could cause erosion.

Mitigation: Model the potential erosive forces resulting from the dam removal and the potential extent of those risks. Riparian vegetation and/or the use of rock armoring can be used to stabilize riverbanks which are subject to increased erosive forces. Nature through the seed bank also rapidly establishes new vegetation in soil close to rivers and streams.

RFPP is at least a 3- to 4-year project beginning in 2023 with multiple tasks and phases of work that each need to be completed to inform and enable the next. We can only be certain of the timeline as we complete each task and phase due to a wide range of variables that may be encountered that could alter planned timing. Work will be expedited as possible to achieve or advance the planned schedule.

The project team holds Partner/planning check-in meetings every two weeks to adapt and update the project timeline on an ongoing basis. Tasks and phases include:

Tasks

• Community Outreach and Education
• Land Acquisition/Construction Easements
• Data Collection/Studies – Pre-Construction
• Preliminary Design
• Permit Applications/Approvals
• Final Design
• Implementation/Construction
• Post Construction Monitoring

Phases of work

• Data analysis/design/permitting
• Site preparation
• Dam alteration or removal
• Channel stabilization
• Landscaping

Key Milestone Schedule Estimation

• Grant Award/Start Date September 1, 2024
  • Public Information Meeting November 21, 2024
• Site Assessment/ Data Analysis September 1, 2024 – May 2025
• Alternative Analysis/Concept/30% Design June 2025
  • Public Meeting (estimated) June 2025
• Permit Design (90% Design) July – September 2025
• Permit Applications Submittal Prep/Submittal September 2025 – October 2025
  • Permit Approvals April 2026+
  • Public Meeting May 2026
• Final Design June 2026
  • Landowners/Community Meeting July 2026
• Construction/Demolition Initiation Currently Summer/Fall 2026 earliest–Summer 2027 latest
• Demolition Currently Summer/Fall 2026
• Stream/Asset Stabilization (As Necessary) Summer 2027 latest

The project team has contracted experts at Dovetail, a Mead & Hunt Company, to provide cultural resources  services. The scope of their work includes a Phase IA cultural resource study of the RMD across the Rapidan River that separates Culpeper and Orange counties in Virginia. The study includes a Phase IA cultural resource reconnaissance survey to gather existing data on the project area and to help coordinate the project’s potential impacts on cultural resources with the DHR. The services are being led by professionals who meet the Secretary of the Interior (SOI) guidelines on cultural resource personnel. The current project is designed to meet regulations to achieve compliance with applicable Federal and County statutes, ordinances, and regulations. Technical studies will follow the DHR’s Guidelines for Conducting Historic Resources Survey in Virginia (2017).

Once studies are complete, mitigation due to alteration of the RMD could include report(s), actual preservation of a piece of the structure, signage, etc. Note that the RMD is not the only contributing resource on the river. In addition, the Mill itself is also a historic resource. This project could trigger a community conversation about the fate of the Mill buildings, as their deterioration is accelerating, with the exception of the Mill office (partially renovated by RI/ACP in 2020). Within the building are milling chutes and equipment potentially useful in the telling of an important story – when the Mill was a thriving center of this community - that could be saved for future generations.

All surveys, data collection, and analyses by participating engineers are being conducted in the first phase to determine whether/how any surrounding properties in the area could be impacted.

KEYSTONE, RTE, DIADROMOUS SPECIES

Alewife (Alosa pseudoharengus)
Blueback Herring (Alosa aestivalis)
American Shad (Alosa sapidissima)
Hickory Shad (Alosa mediocris)
American Eel (Anguilla rostrata)
Striped Bass (Morone saxatilis)
Sea Lamprey (Petromyzon marinus)

ADDITIONAL NOTABLE, POTENTIAL KEYSTONE SPECIES

Several freshwater mussel species:
Yellow Lance (Elliptio lanceolata)
Green Floater (Lasmigona subviridis)
Dwarf Wedgemussel (Alasmidonta heterodon)
Triangle Floater (Alasmidonta undulata)
Carolina Lance (Elliptio angustata)
Eastern Elliptio (Elliptio complanata)
Carolina slabshell (Elliptio congaraea)
Northern Lance (Elliptio fisheriana)
Atlantic Spike (Elliptio producta)
Yellow Lampmussel (Lampsilis cariosa)
Eastern Lampmussel (Lampsilis radiata)
Tidewater Mucket (Leptodea ochracea)
Eastern Floater (Pyganodon cataracta)
Creeper (Strophitus undulatus)
Paper Pondshell (Utterbackia imbecillis)
Alewife Floater (Utterbackiana implicata)

There has been general discussion about increased public access, with many differing views voiced in the communities, but there are no current plans or budget in the RFPP project for such amenities.

Eminent domain is almost always exercised by government agencies. Rapidan Mill Dam is owned by a private landowner so eminent domain is not applicable to this project.

This is to be determined as part of the historical and cultural resources review portion of the project.

The pool or pond behind the dam likely raises the water table immediately adjacent to the shoreline equal to its depth then quickly diminishing as distance increases. In this very localized area, the water table would be maintained roughly 10-11 feet higher than during a drought.

The Town of Orange water intake is roughly 10 river miles upstream from Rapidan. The pool above the dam extends roughly 1 mile upstream to the confluence with the Robinson River. There is no drought related impact of the RMD pool on the Town of Orange water supply. And RMD is not a reservoir, so it does not provide any meaningful quantity of water to draw from during a drought.  It’s a run-of-river dam, water in equals water out.

The Rapidan Mill Dam is a shallow low-head dam. A low head dam is not a flood control structure and in fact is designed to raise water elevation above it. A low head dam is designed to have water run continuously over the top of it creating potentially dangerous hydraulic conditions below it.

Restoring Natural Flow – Alteration of a low head dam reduces the chance of sudden, catastrophic flooding due to dam breaches. Alteration does not increase downstream flood risk.

Enhancing Sediment Transport – Dams trap sediment, which can cause riverbeds downstream to erode and become deeper. When a dam is altered, sediment is redistributed more naturally, which can improve the river’s ability to handle floodwaters by stabilizing banks and reducing rapid channel shifts.

Aging or poorly maintained dams may fail under extreme weather conditions, leading to uncontrolled releases of the pool behind the dam and potential flooding downstream. Dam alteration eliminates this risk entirely.

Like any structure, dams must be maintained to be viable. With no revenue generating capability, no funds are available for maintenance by the owner - ACP. This is now a common problem with old mill dams across the US. American Rivers notes the following in a recent story:

Increasing frequency of extreme weather impacts over the last two decades often exceed the flow capacity for which dams were designed or threaten aging dams that are often already in poor condition. In 2024, the Rapidan Dam in Minnesota partially failed after days of intense rainfall. At least 36 high-hazard dams — dams that in the event of failure would likely cause high value property damage or loss of life —failed or were damaged by Hurricane Helene in addition to dozens of other non-jurisdictional dams.  In Vermont, at least five dams failed and 50 dams sustained enough damage to require repair following multiple historic flooding events throughout July and August.

Northern Snakehead (Channa argus) have been widely stocked illegally in Virginia, identified to date in more than 23 lakes in Northern Virginia alone. Snakeheads were first introduced into the Rappahannock system after Embrey Dam came down and have since been migrating as far upstream as at least Sperryville in Rappahannock County.  They have ascended as far upstream on this reach of the Thornton River every spring and then disappear in a few weeks, according to Virginia state Dept of Wildlife Resources (DWR) fisheries biologists. They have been unable thus far to establish significant populations in higher elevation streams and rivers (think Smallmouth Bass habitat) because ideal snakehead habitat consists of tidal, muddy, vegetated flats. DWR fishery biologists support providing fish passage even when there is the potential for Northern Snakehead range expansion because reconnected habitats in upstream river reaches are not preferred by snakeheads, and illegal stocking will likely continue to occur providing range expansion opportunities even without fish passage provision.

Learn More

Anglers will enjoy increased fish population density in Rapidan as well as more rapids to access in portions of the pool that is now submerged.  While there may be some water depth shifts in the short-term there won’t be any significant long-term increase or decrease in fishable areas in the reach downstream once the river returns to a state of equilibrium.

Riparian species will flourish with greater food supply from the higher population of fish reaching the reopened rivers of the watershed.

Farmers in Virginia can withdraw up to 10,000 gallons per day without the need for a permit regardless of whether the water is withdrawn from impounded water or a free-flowing river. However, it could be more difficult to access water during low flow periods from the river in a free-flowing condition.

Members of the project team are highly qualified with river restoration and dam removal experience.

That answer as provided by historic preservation consultants has changed over time. Years ago, when the village was nominated to the National Register the Mill was determined to be "non-contributing" to the district. The dam itself wasn't mentioned. Most recently, for the Rapidan-Clark Mtn. Rural Historic District, another historic resources assessment was completed, and the Mill, and this time the dam itself, was found to be contributing. Clearly the mill and dam are historically important. That's why American Climate Partners has hired a cultural resources consultant and we will be working with the Virginia Department of Historic Resources.