New Outlet Structure

September 9, 2016

 

The new Outlet Structure or Weir was completed in early September.   The Indiana Department of Natural Resources (IDNR) Division of Water has been studying the structure for replacement for a number of years.  In 2000, staff from the Project Development Section of the Division of Water felt the structure was in need of increased monitoring for eventual repairs or replacement.  Project prioritization and monitoring lead the staff at the Division of Water to conclude a “significant reconstruction” would be needed to provide a stronger structure than existed.   Here are the highlights of the construction project:

 

  • Unlike the old steel sheet piling construction, the new structure consists of compacted crushed stone, concrete, new 3/8 inch thick steel sheet piling by 20 feet deep and over 34 feet long, and welded 1/2 inch diameter rebar to reinforce the concrete and to tie the concrete to the deep foundation steel 
  • The weir crest wall is 32.4 feet in length with a thickness of 2.0 feet with a sea level elevation of 713.9 feet – when you add in the wing walls the total length is just over 39.0 feet
  • In front of the weir crest wall is an angled approach apron that is 4.0 feet thick and is held into place by the 3/8 inch sheet piling and rebar – rebar is also welded to the rebar in the weir structure.  The purpose of the approach apron is to prevent “ice push” which was the major issue that caused the original outlet structure to fail
  • Behind the weir is a “stilling basin” that is approximately 1.0 foot below the weir crest wall – it is also contains rebar – along with the existing steel sheet pilings and connects to both the weir and approach apron
  • The final component is an existing concrete sill before any overflow water spills into the stream/drainage side located at the west end of the weir

 

New Outlet Structure.jpg