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- Drainage Areas of Iowa Streams Bulletin #7 (Report Number HR-029)
 


FLOOD PLAIN OR FLOODWAY DEVELOPMENT: WHEN APPROVAL IS REQUIRED

Bridges, Culverts, Temporary Stream Crossings, and Road Embankments

When Department Approval is Required Per IAC Chapter 71
Approval by the department for the construction, operation, and maintenance of bridges, culverts, temporary stream crossings, and road embankments shall be required in the following instances:

567-71.1(455B) Bridges, culverts, temporary stream crossings, and road embankments. Approval by the department for the construction, operation, and maintenance of bridges, culverts, temporary stream crossings, and road embankments shall be required in the following instances.

71.1(1) Rural area-floodway. In rural areas, bridges, culverts, road embankments, and temporary stream crossings in or on the floodway of any river or stream draining more than 100 square miles. (NOTE: Channel modifications associated with bridge, culvert or roadway projects may need approval; see 567-71.2(455B).)

71.1(2) Rural area-floodway and flood plain. Road embankments located in the floodway or flood plains, but not crossing the channel of a river or stream draining more than 10 square miles, where such works occupy more than 3 percent of the cross-sectional area of the channel at bankfull stage or where such works obstruct more than 15 percent of the total cross-sectional area of the flood plain at any stage. In determining 15 percent occupancy of the flood plain, the concept of equal and opposite conveyance as defined in 567-Chapter 70 shall apply.

71.1(3) Urban areas. In urban areas, bridges, culverts, road embankments and temporary stream crossings in or on the floodway or flood plains of any river or stream draining more than 2 square miles.

Application Forms, Checklists & Guidance:

Application Form(s)
*.pdf
Joint Application Form
PDF File Format
Hydrology Pre-Approval Request
PDF File Format
 
Application Guidance
*.pdf
Accelerated Review Process for Bridges
PDF File Format
Pedestrian Bridge Analysis Guide
PDF File Format
 
Application Checklist(s)
*.pdf
Checklist and Guidance for Bridge Project Applications
PDF File Format

Aerial photographs can be obtained online at: http://ortho.gis.iastate.edu/search.html.

 

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