HR Green Selected to Design Iowa River Bridge in Louisa County
Louisa County has selected HR Green, Inc. to prepare bridge and roadway design plans and analyze the probable environmental impacts associated with the replacement of the County Highway X99 Bridge over the Iowa River at Wapello in accordance with the National Environmental Policy Act (NEPA). The first phase of the project includes evaluating alternatives and developing preliminary engineering plans to the level necessary to complete the NEPA documentation. During the second phase, final design and plan preparation for the selected alternative will be completed.
“We are excited to once again be working on providing critical infrastructure improvements for Louisa County residents,” said Project Manager Stan Stallsmith. HR Green completed a similar bridge crossing the Iowa River near Oakville, IA in 2014.
The existing bridge is reaching the end of its useful life. The age, width, and the “two girder design” of the bridge create unique challenges for the design and construction of the new bridge. Construction staging and removal of the existing bridge are complicated due to the two-girder design of the bridge’s main unit. The HR Green team will explore the use of Accelerated Bridge Construction (ABC) methods to identify cost effective ways to shorten the duration of construction and the reduce the impact that construction will have on the community.
Preliminary design of the new bridge will require environmental field studies and compliance with the National Environmental Policy Act (NEPA). The NEPA process will include data collection, agency coordination, document preparation and public involvement. Field studies will be completed to determine if the project could have potential impacts on resources such as wetlands, floodplains, vegetation, wildlife, land use, zoning and solid and hazardous waste. The information collected will be used to complete the Iowa DOT’s Concept Statement and will be provided to regulatory agencies such as the Fish and Wildlife Service, the Iowa DNR, the State Historical Preservation Office and the US Army Corps of Engineers to obtain permits, and to receive NEPA clearance from the Federal Highway Administration (FHWA).
In addition, final design of the new bridge will require coordination with the Iowa DOT and the FHWA to integrate the preliminary and final design standards required by the Offices of Local Systems and Bridges and Structures and to satisfy all funding requirements.