Pinicon Ridge Park Dam Modification Project

Pinicon Ridge Park Dam

Pinicon Ridge Park Dam

The Linn County Conservation Board owns the low-head dam in Central City. The dam was built in 1967 on the Wapsipinicon River downstream from Pinicon Ridge Park, just east of Highway 13. The dam surpassed its expected 50-year life and the Board is exploring long-term solutions.

Initiatives to modify low-head dams have been taking place throughout Iowa to not only improve the water quality of rivers and streams, but to improve safety, increase the environmental health and population of aquatic life in the river, and to provide recreational opportunities. The Linn County Conservation Board, with all these goals in mind, has been studying the issue for several years. An input session was held in 2017 where the public provided their outlook on the dam and future for the region. 

A public open house was scheduled for March of 2020 to view preliminary concepts, but was cancelled due to COVID-19. Due to the ongoing pandemic, Linn County Conservation has provided additional information from staff and professionals in the field about these concepts and to address the priorities of this modification.  

Preliminary Dam Modification Concepts

Rock Arch Rapids Concept

PRP Rock Arch Rapids Concept

Dual Design 1 Concept

PRP Dual Design 1 Concept

Dual Design 2 Concept

PRP Dual Design 2 concept

Three concepts for a dam modification project have been designed by WHKS and Company. 

  • Rock Arch Rapids: Traditional dam modification design that addresses safety concerns and fish passage. 

        Flyover of Rock Arch Rapids Concept (Video)

  • Dual Design Concept 1: Integrates function of the rock arch rapids, while combining recreational opportunities through a series of drop pools.
  • Dual Design Concept 2: Integrates function of Dual Design Concept 1. These drop pools are extended south of the bridge to lengthen recreational opportunities, such as fishing and paddling. 

       Flyover of Dual Design Concept 2 (Video)

Nate Anderson P.E., Senior Associate for WHKS has produced two presentations to further explain these options, that could address the goal of improving safety, fish passage, and recreational opportunities at the site. He further explains river hydraulics, which is key for the feasibility of any modification project.

Design Concepts (Video)

River Hydraulics Along the Wapsipinicon River and Dam Site (Video)

Dam Modification Benefits

Safety and Pinicon Ridge Park Concerns

dam danger sign

Numerous river rescues have taken place around the state at low-head dams (including two deaths over time at the Pinicon Ridge Park dam). These structures pose a risk to swimmers, boaters, and anglers, due in part to the recirculating current below the dam that can trap victims. Iowa Department of Natural Resources River Programs coordinator Nate Hoogeveen discusses the improvements to safety that dam modification projects create.

Dam Safety - Iowa Department of Natural Resources (Video)

A dam modification project can reduce concerns of safety at the dam site and also near Pinicon Ridge Park. These projects can be constructed in a way not to negatively impact park recreation and resources. Aaron Batchelder, Pinicon Ridge Park Ranger, says a modification can additionally produce long term benefits for park users and wildlife.

Dam Safety/Pinicon Ridge Park Impacts - Linn County Conservation (Video)

Fish and Mussel Passage

walleye caught by boat

The Wapsipinicon River is abundant in over 800 aquatic species, and the dam structure is currently an impediment to passage upstream. Data has been collected from successful migration patterns after other dam modification projects in eastern Iowa. Paul Sleeper, Fisheries Biologist for the Iowa Department of Natural Resources, explains the negative impacts a low-head dam has to aquatic life and the environmental health of the river.  

Fish Passage - Iowa Department of Natural Resources   (Video)

Fish passage is critical for mussel passage along the Wapsipinicon River. Efforts continue to restore the mussel population, including the endangered species Higgins eye pearlymussel. Louise Mauldin, Fisheries Biologist from the U.S. Fish and Wildlife Service and her team, detail the importance of freshwater mussels. 

Mussel Community and Importance of Fish Passage at the Dam Site - U.S. Fish and Wildlife Service (Video)

The Reproductive Cycle and Importance of Freshwater Mussels - U.S. Fish and Wildlife Service (Video)

River Recreation

Kayak access at Buffalo Creek Park

The Pinicon Ridge Park dam has hindered fishing opportunities up and downstream from the dam as well as vessel portage along the Wapsipinicon River. Chuck Ungs, Linn County Conservation Education Specialist, is an avid angler and paddler. He shares the improvements and opportunities are created for outdoor recreation with a dam modification project. He stands along the modification project in Manchester as an example of successful benefits.

River Recreation - Linn County Conservation (Video)

Economic Development

whitewater park in Manchester

With concerns of constant flooding from the Maquoketa River and seeking ideas on how to improve the quality of life for the community, the city of Manchester undertook a process to remove a low-head dam. City Manager Tim Vick says every dam modification project is different in each situation, but a whitewater park for them has led to a boost in business opportunities and tourism.  Although no whitewater park is included in any Pinicon Ridge Park dam modification project, it is an example of what type of project worked best for their community and situation.

Economic Development - City of Manchester (Video)


We appreciate the public for taking the time to view the concepts and watch the videos that pertain to the important issues related to this project. The public online survey, that was available on this page from July 6 to July 24 may have closed, but staff and the board continue to gather information. Efforts will continue this summer by Linn County Conservation to determine the best outcome for the Pinicon Ridge Park dam.