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INDOT Hydraulic Engineering designs or reviews all waterway projects including, but not limited to, bridges, culverts, storm sewers, and detention ponds along state roads, U.S. routes or interstates or local projects built with state or federal funds.  


Hydraulic Department Project List

INDOT hydraulics is in the process of working on a live embedded worksheet to show the status of projects for consultants and districts.  For the time being, we have created a PDF of the list of projects which will be updated on a weekly basis on Mondays with exception being on holidays in which they will be updated the following day. If you have requested a project through the Hydraulic Request Application (HRA), please note that it will not be displayed on this list and its progress can be viewed on the said application.

Pipe Lining Design

Pipe lining is a technique for maintaining existing corrugated metal pipes in which a smooth walled structure is installed within the exisiting pipe and grouted into place.  This practice does remove water way area, but the roughness factor is reduced.  Projects are analyzed to meet or better existing conditions and appropriate scour protection is installed to further protect the embankments for the typically higher velocities.

Another way for maintenance to prolong the life of a pipe is by paving the invert of the pipe.  This process lines the floor of the exisiting pipe with approximately a five inch thick smooth concrete flooring.  This application is useful if the floor of the pipe is deteriorating while the walls and top of the pipe are in satisfactory condition.

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Developing Design Guidance

The following list contains design guidance that may not be reflected in the Indiana Design Manual (IDM).

  • The invert of a jack and bored pipes will be set to a minimum of 1 ft above the invert of the existing pipe to be lined.  If this is not feasible due to site constraints, please coordinate with the INDOT Hydraulic Engineering.
  • All liner options should have the inverts of the pipes raised by the liner thickness.  Backwater should then be calculated by taking the existing culvert's backwater and subtract the difference of the headwaters.
  • HY-8 v.7.2 is currently the only version permitted for use by the INDOT Hydraulic Engineering.  Please click the following link to download the software (Active Design Memoranda16-34).
    • Due to Window's updates, HY-8 v.7.2 will not install without first installing the  application that can be downloaded by clicking here. After this application is installed, HY-8 v.7.2 may be installed.
  • Jack and bore pipes as part of a culvert liner project under the interstate are required to have a minimum inner diameter of 18 inches.
  • For consistency of sump requirements and without more detailed information, if the soil map unit description contains the word sand, the required sump from IDM Fig 203-2E should be based off of the "Sump Required for Stream Bed of Sand" column.
  • Reinforced concrete boxes and 3 sided structures under 18 foot span should incorporate corner haunches as produced by the manufacturer.  The spreadsheet provided below, named Specialty Structure Coordinate Generator under Other Links and Forms, includes the haunch data from the manufacturers. 
  • A flow chart has been developed to help designers select which structure and liner options should be analyzed.  Modeling guidance has also been included.  This chart can also be found as Proposed Structures Flow Chart under Other Links and Forms below.
  • For a scour analysis and if a bridge is on piles, the traditional "10 foot rule from the bottom of the piles" is no longer used.  If a the piles are in anyway exposed during a scour event, the scour determination is sent to part B of the scour memo and the bridge structure engineer at INDOT will determine the scour criticalness.  If the piles are undermined, then the bridge may be determined scour critical from the hydraulic engineer.
  • Semi-smooth options will no longer be required to be given as replacement options for small structures.
  • CLARIFICATION OF IDM 203-2.02(02) 2.a.1.: The replacement structure does not have to have the same span as the existing structure when the existing structure is going from pipe to a proposed box type structure.  However, the cross-sectional structure area cannot be reduced. 
    • Example:  An existing twin 8 foot diameter pipes may be replaced with a proposed 15x7 box structure, even though the twin pipes have a total span of 16 feet while the box has 15 feet, as long as the proposed total area is equal to or greater than the existing.  In this case, the existing area is about 101 square feet, while the proposed box (with haunches) has an area of 103 square feet.
    • Example 2:  An existing 6 foot diameter pipe cannot be replaced with a 5x5 box because the existing pipe has an area of 28 square feet, while the proposed box (with haunches) has an area of 23 square feet.
  • Existing single span structures greater than or equal to 20 ft and up to 30 ft in perpendicular span to the conveyed channel may have proposed structures sized in HY-8 version 7.2. This only applies to proposed structures that can be modeled in HY-8 using a pre-defined HY-8 shape in the culvert data section of the crossing data input, and have a perpendicular span to the conveyed channel within the aforementioned span range.  The Office of Hydraulics must be consulted before modeling slab-top structures within the aforementioned span range.
    • Note: Three-sided and four-sided concrete structures that are less than 18 ft in perpendicular span to the conveyed channel will still need to be modeled with HY-8 incorporating haunches using the user defined shape options
  • When analyzing an existing structure that is showing overtopping, the designer should NOT artificially raise the road to analyze headwater elevation as it may exaggerate the backwater total, but rather make certain that the discharge through the liner/new pipe at overtopping is greater than the existing.
  • All three-sided structures are no longer required to be sumped unless requested by the county surveyor for legal drains.
  • When conducting scour design, the IDM states to use the channel only, however due to the fluctuation of channel embankments, it may not be the highest value of the calculations. Therefore the greatest contraction scour depth between the left, right or center values found in Hec-RAS should be used when reporting the scour depth.
  • For a culvert rehabilitation project, a pipe liner should not be used if it has a inner diameter less than the minimal allowable for the particular roadway facility.  See IDM Figure 203-2B.  If the host pipe is a median drain or storm sewer, the pipe liner should not have an inside diameter less than 12".

  • If a dual hydrologic soil group is within a watershed, then the soil should be considered undrained (D-soil) unless it can be shown that the water table is more than 24 inches below the ground surface. If desired, the groundwater depth can be found using the USDA Websoil survey.

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Sample Documents

The following sample documentation are examples of what we at INDOT Hydraulic Engineering would like to receive from consultants. The format of the reports should follow IDM Chapter 203.

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Submitting Documents

Documents should be submitted using ERMS and emailing the appropriate INDOT Coordinator.   Please allow for up to 45 days for all reviews and designs for each submittal and 14 days for any permit application.

Starting July 1, 2018, design submittals for small structures, scour and bridge reviews will require the respective memo template below to be filled out  and submitted along with the hydraulic report, design files, and QA form. There is an instruction sheet for each template.

Submit the completed memos in word format for review. For scour submittals, submit the existing bridge plans and pile records as a separate documents from the report.

As of July 1, 2018, LPA projects will no longer be reviewed by INDOT Hydraulics unless the project meets one or more of the conditions found within Memo 18-12.

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Prequalification to Submit Driveway Permits

INDOT Hydraulics has launched a Driveway Permit Training Course.  It is a course that we have developed for consultants that are submitting driveway permits that include drainage design that drains to the INDOT right-of-way.  We will be requiring that the course be completed for a consultant to become prequalified for this type of work.  In August of 2018, we will no longer review drainage design submittals for driveway permits from consultants that are not prequalified.

If you would like to be signed up for the course please send your first and last name as well as your email address to Hydraulics@indot.IN.gov Please allow 1-2 weeks for enrollment.

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Small Structure and Culvert Designs Training Course

INDOT Hydraulics has launched a Small Structure and Pipe Hydraulics Training Course.  It is a course that we have developed for consultants that are submitting small structure and culvert designs.

If you would like to be signed up for the course please send your first and last name as well as your email address to Hydraulics@indot.IN.gov Please allow 1-2 weeks for enrollment.

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Bridge Hydraulics and Scour Designs Training Course

INDOT Hydraulics has launched a Bridge Hydraulics Training Course.  It is a course that we have developed for consultants that are submitting Bridge and Scour designs.

If you would like to be signed up for the course please send your first and last name as well as your email address to Hydraulics@indot.IN.gov Please allow 1-2 weeks for enrollment.

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Storm Sewer and Detention Designs Training Course

INDOT Hydraulics has launched a Storm Sewer and Detention Design Training Course.  It is a course that we have developed for consultants that are submitting storm sewer and detention designs.

If you would like to be signed up for the course please send your first and last name as well as your email address to Hydraulics@indot.IN.gov Please allow 1-2 weeks for enrollment.

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Upcoming Training

Training Date PDH Host Location Registration Form

INDOT Highway Design Conference

June 29, 30, and July1 (Tentative) TBA INDOT Virtual TBA

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Related Links and Documents

Design Guidance

Hydrology Links

Other Links and Forms

These spreadsheets are intended as tools to provide convenience in hydraulic design.  There is no guarantee, either implied or explicit, as to the accuracy or reliability of the results provided by these spreadsheets.  By using any of these spreadsheets, the user agrees to take full responsibility for the input data and for the interpretation and use of the spreadsheet results.

Past Presentations

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Frequently Asked Questions

  • When doing a bridge scour analysis, should I take the depth from the downstream invert or upstream invert?
    • When doing a bridge scour analysis, the scour depth should be taken from the lowest invert elevation, whether it is upstream or downstream.
  • What kind of inlet type should I choose when lining a pipe?
    • When initially lining a pipe with CIPP, the inlet configuration should match whatever is in the field, unless the existing pipe is projecting. In which case, the liner should have an inlet configuration of mitered to conform to slope. 
    • When initially lining a pipe with HDPE liner, the inlet configuration should have an inlet configuration of mitered to conform to slope even if the existing pipe has a headwall. If a headwall or bevel edge is needed for the HDPE liner to perform correctly, it will need to be constructed with the project.
    •  If you are putting in a 5" paved invert, the inlet configuration should simply match the existing configuration.  If you need to improve the inlet configuration, then adding a headwall or a headwall with bevel edge is acceptable with the proposal.
  • HY-8 v.7.2 does not allow me to perform culvert analysis with reverse slope pipes. What should I do when the existing pipe has the inlet lower than the outlet?
    • If the existing pipe has a reverse slope, we recommend bringing the inlet invert to the elevation of the outlet creating a flat pipe.  
  • What type of inlet configuration do I use for a pipe end section? (metal, grated box, etc.)
    • Inlet configurations for the pipe end sections: grated box types I and II, metal end sections, precast concrete, and safety metal culvert end sections for smooth pipes is recommended to have a the inlet configurations similar to that of a headwall.
  • What region of the Huff Distribution Curve does my project correspond to?
    • The 50% Huff Distribution Curves have been set in four locations within the state of Indiana.  For consistency purposes, this map - Huff Distribution Regions - shows which county belongs to which region.
  • Which quartile of the Huff Distribution Curve do I use for hydraulic analysis?
    • According to the LTAP Stormwater Drainage Manual, the first quartile is set for any storm duration less than or equal to 6 hours.  The second quartile is set for any storm duration greater than 6 hours and up to and including a 12-hour storm.  The third quartile is for storms greater than 12 hours and up to and including a 24-hour storm.  The fourth quartile is for any storm greater than 24 hours.
  • Which velocity, average or max, should be used in determining scour protection for bridges?
    • Scour protection for bridge design and rehab is based primarily on the following criteria (based on IDM Fig. 203-2J and Fig 203-3B):
      • The abutments shall be protected with a minimum size rip rap to that of the average velocity of the bridge.
      • The piers shall be protected with a minimum size rip rap to that of the max velocity of the bridge determined by velocity distribution.
  • What is the minimum pipe size for a paved invert option?
    • ​The minimum pipe size for a paved invert rehabilitation is for the existing pipe to have a minimum span and rise of 4 ft.
  • How do I know if I need a Construction in a Floodway (CIF) permit for a project?
  • How should I present the size of a 3-sided structure in a hydraulics memo?
    • A 3 sided structure, whether it is a flat top, arch top, or slab top, should have its low structure elevation, flow line elevation, and sump labeled in the hydraulics memo with their respective line in the table.  The span should be labeled within the type of structure line.  To avoid confusion, the rise of the structure should not be stated as the flow line elevation, sump depth, and low structure elevation will be the necessary information for the structural and environmental engineer to use in the designs.
  • What size particle should I use for scour analysis if I do not have a soil borings report?
    • When using live bed scour for standard stream crossings, please use the minimum standard 0.01 mm for the d50 soil size. If the structure is an overflow structure, then clear water scour should be used and HEC-18 updated in 2012 now states to use 0.2 mm as a minimal size for the d50 soil size. If the structure is both a natural stream and an overflow structure for a larger stream, then both scour types should be checked under their respective flow rates and soil sizes and the larger scour result should be used.
  • Do I need to send my median drain computations to INDOT Hydraulics for review?
    • Please send all median drain reports, plans and computations to the office of hydraulics for review.  Reference to the INDOT Hydraulics presentation on median drains is recommended. 
  • For projects with multiple structure types (e.g. bridge, culvert, detention), what is the proper way to submit the projects?
    • The proper way to submit projects with multiple types is to separate the types by category in a limited fashion. For example culverts will be their own submittal as well as detention in its own and storm sewers in its own.  Culvert submittals should be limited to ten structures.
  • How do I open the zipped files uploaded to ERMS?
    • The zip files can be opened using a free software called 7-zip and can be downloaded via the website https://www.7-zip.org/download.html.  It is recommended to use the most up to date version.
  • When do I consider needing to sump a structure?
    • Three-sided structures, spill through structures, storm drain systems, and structures with inlet depressions should not be sumped. For other culverts, sumping is required unless the Waters Report determined the location not to be a Waters of the US nor Waters of the State.

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Contact Information

Mark Bailey
Director of Hydraulics
Indiana Department of Transportation
100 N. Senate Ave., N758 - Hydraulics
Indianapolis, IN 46204


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