littleton dam mitigation

littleton, IA

Services:

• Hydrologic & Hydraulic Modeling
• Dam Mitigation
• River Restoration
• Planning and Design

Service Area:

• Water Resources
  • Dam Mitigation
  • River Restoration

Market Sector:

• State

The existing Littleton Dam is a low head concrete dam built in the 1930's located on the Wapsipinicon River in Littleton, Buchanan County, Iowa.  The dam impedes movement of native fish to habitat along the Wapsipinicon River and tributaries.  The dam has experienced deterioration and damage over the years.  There are visible structural issues in its current condition.  The dam presents public safety concerns due to drowning and potential failure.  There have been at least nine documented deaths at this dam location.    

The Iowa Department of Natural Resources, in conjunction with the National Fish Passage Program through the U.S. Fish and Wildlife Service Mitigation propose to mitigate the dam to provide ecological and public safety benefits.  The existing dam will be removed and replaced with a constructed rock arch rapids to allow for fish passage. Streambank stabilization in affected areas consists of reshaping the slopes and providing bioengineering.  The project will also feature a constructed rock outcropping to provide access for fishing and walking. The removal of the dam and installation of rock arch rapids will provide fish passage, reconnect 375 upstream, mainstream, and tributary miles, and address safety and structural issues.  

LT Leon worked with DNR staff to develop preliminary and final construction drawings, design report, cost estimates, and conceptual renderings.  LT Leon refined the previously developed existing conditions HEC-RAS model and developed new proposed conditions HEC-RAS models.