Floodplain Delineation of Indiana Streams

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					Floodplain Delineation of
    Indiana Streams

       Allison Craddock
        Tom Gormley
       Jessica Tempest
         Erin Wenger
     Problem Statement
Flooding due to
recent development
in rural areas of
Indiana has
heightened public
concerns and
requires the
development of flood
plain mapping in
previously
       Objectives
• Create a hydraulic base model
• Delineate areas most prone to
  flooding
• Design a flood control
  structure to reduce area of
  impact
• Recommend the next course of
  action
              Methods
• Analyze topographic data to determine
  representative cross sections
• Determine 100 year flow data from
  government resources
• Obtain bridge data from Highway
  Department
• Insert data into Hec-Ras
• Based on output, design flood control
  structure
        Why Use HEC-RAS?

• Hec-Ras, developed by the Army Corps of
  Engineers, is the standard model used for
  floodplain delineation.

• Performs one dimensional hydraulic analysis
  for steady and unsteady river systems.

• Energy loss is calculated using Manning’s
  Equation.
                HEC-RAS
• Inputs                  • Outputs
  – Flow Data               – Cross Section
    • Drainage area           Plots
    • Discharge             – Rating Curves
  – Cross Section           – Detailed Tabular
    Data                      Output at a
    • Manning's “n”           Specific Cross
    • Station/Elevation       Section
  – Bridge                    • Water Surface
    Information                 Elevation
    • Height                  • Flow area of
                                channel
    • Restrictions
                              • Total Discharge
       Sensitivity Analysis
• Flow rate, location of bank station, and
  Manning’s “n” value for both were
  varied to see the results of the change
  on velocity, top width, and elevation.

• These values were chosen due to their
  variability in Hec-Ras.
   Results of Sensitivity Analysis

                                               Sensitivity Analysis for Q
• Velocity and top
width proved to be                    2
the most sensitive                   1.5


                       Sensitivity
                                                                             Velocity
for flow rate.
                                      1                                      Top Width
                                                                             Elevation
• Analyzed inputs                    0.5
have a minimal                        0
impact on elevation.                       0     2000          4000   6000
                                                     Q (cfs)
                 Calibration
• The field data used was a floodway/flood boundary
  map for a reach directly above and adjacent to the
  model.

• A top width was measured off the flood map and
  used to compare to the top width predicted by the
  model.

• The model was calibrated coarsely first by varying
  the flow rate into the cross section.

• Once the top width was close to the observed value,
  an attempt was made to refine the calibration using
  Manning’s n value on both the stream channel and
           Results of Calibration
                        Top width measured: 312.5 ft


Run #      Flow   Manning’s Channel   Manning’s Bank   Top Width Predicted

Original   3100         0.04               0.07              284.96

   1       3200         0.04               0.07              288.64

   2       3300         0.04               0.07              293.89

   3       3400         0.04               0.07              297.95

   4       3600         0.04               0.07              305.53

   5       3700         0.04               0.07               309

   6       3800         0.04               0.07              312.28

   7       3800         0.038              0.07              313.46

   8       3800         0.04               0.06              308.51
     Case Studies

Jordan Creek – Allison Craddock
 Burnett Creek – Tom Gormley
 Haw Creek – Jessica Tempest
  Indian Creek – Erin Wenger
             Jordan Creek
               Geographical Data


• 2 mile reach
extending south from
State Road 26
• Township 23 N, Range
5 W, Tippecanoe
County, Indiana
• Model acts as a
southern continuation of
Green Meadows
residential development
analysis
                 Design Considerations

• Model should be able to couple with preexisting HEC-2
  data north of SR 26

•    Creek bed experiences a fluctuation in topography
    along its path, moving from a narrow V-shape to wide,
    low sloping terrain

•    To minimize flooded areas, a levee will be constructed
    primarily on the eastern side of the creek, and the creek
    bed will be excavated further

•    Reshaping of creek area should not have a negative
    impact on the local ecosystem, and alleviation of
    flooding in one area should not encourage flooding or
    erosion in other areas.
                           Cross Sectional Analysis and
                                     Design
                       senior design 2004 jordan creek    Plan: Imported Plan 01         04/13/2004



                                             .07                        .    .07
                 650                                                    0                             Legend

                 645
                                                                        4
                                                                                                      EG PF 2
                                                                                                                 Before:
                                                                                                      WS PF 2    Shallow side of creek
Elevation (ft)




                                                                                                                 will flood during a 100
                 640                                                                                  EG PF 1
                                                                                                      WS PF 1
                 635
                                                                                                      Ground
                                                                                                                 Year storm.
                 630                                                                                  Bank Sta


                 625
                       0        100         200          300         400           500         600
                                                 Station
                 ALTERED senior design 2004 jordan creek       (ft)Plan: Imported Plan 01    04/14/2004



                                             .07                        .    .07
                 650                                                    0                             Legend

                 645
                                                                        4
                                                                                                      EG PF 2
                                                                                                                 After:
                                                                                                      WS PF 2    Construction of a levee combined
Elevation (ft)




                                                                                                                 with trenching and widening of creek
                 640                                                                                  EG PF 1
                                                                                                      WS PF 1
                 635
                                                                                                      Ground
                                                                                                                 results in usable land.
                 630                                                                                  Bank Sta


                 625
                       0        100         200          300         400           500         600
                                                    Station (ft)
                Results
• Flooding area is minimized

• Land previously in danger of flooding
  as well as newly constructed levee
  may be used to expand local
  agricultural practices

• Erosion by flooding is kept to a
  minimum
Burnett Creek
                 Pre Design
 • During a 100 year                                   Burnett    Plan: Plan 04     04/13/2004

 storm,                                      660
                                                            .08                .1        .08
                                                                                                        Legend


   the waterway splits at                    650
                                                                                                        EG PF 1
                                                                                                    WS PF 1
                                             640                                                        Ground

   the I-65 overpass.


                            Elevation (ft)
                                                                                                    Bank Sta
                                             630

• By reshaping the channel                   620


  where the waterway splits,                 610


                                             600

  the floodplain will be greatly                   0      500          1000
                                                                    Station (f t)
                                                                                      1500       2000




  reduced.
                                             Channel Split                          Main Channel
                Post Design
•Soil will be taken from                                 BurnettDesign    Plan: Plan 04   04/13/2004


 various locations and used                    660
                                                                 .08                .1       .08
                                                                                                              Legend

                                                                                                              EG PF 1

 in the reshaping of the land.
                                               650
                                                                                                          WS PF 1
                                               640                                                            Ground




                              Elevation (ft)
                                                                                                          Bank Sta
                                               630


•The dig areas will:                           620



  reduce erosion                               610



  decrease water elevation.
                                               600
                                                     0         500          1000          1500         2000
                                                                         Station (f t)




•All soil will be excavated from                             New Channel
 this location.
                 Recap of River Station 3508
                                 Before Design                                                                               After Design

                           Burnett    Plan: Plan 04     04/13/2004                                               BurnettDesign    Plan: Plan 04   04/13/2004

                                .08                .1        .08                                                         .08                .1       .08
                 660                                                        Legend                     660                                                            Legend

                                                                            EG PF 1                                                                                   EG PF 1
                 650                                                                                   650
                                                                        WS PF 1                                                                                   WS PF 1
                 640                                                        Ground                     640                                                            Ground
Elevation (ft)




                                                                                      Elevation (ft)
                                                                        Bank Sta                                                                                  Bank Sta
                 630                                                                                   630


                 620                                                                                   620


                 610                                                                                   610


                 600                                                                                   600
                       0      500          1000           1500       2000                                    0         500          1000          1500         2000
                                        Station (f t)                                                                            Station (f t)




             Excess                    Main Channel                                                                            New Channel
                Floodplain Map




Note: Original Floodplain is based on Tippecanoe’s floodplain estimate
       found in Arcmap.
            Final Results
• All flow is contained within the
  channel.

• The total land eliminated from the
  floodplain is estimated at 977.3
  hectare. (2415 acres)

• The land can now be used for
  development.
                Haw Creek
 Site Characteristics

• Approximately a 5 mile
  reach between
  Columbus and Hope,
  Indiana

• Located in Township
  10 N, Range 6 E,
  Bartholomew County

• Connects Columbus FIS
  and Hope FIS models
             Design Criteria
• Significant flooding in the area between the 450
  North Road Bridge and the 550 North Road bridge
  has caused loss in farmland.

• To reduce flooding in this area, a levee will be
  constructed and the channel will be excavated to
  contain the flow in the channel in this area.

• The effects of this design must not increase
  flooding at other locations along the stream.

• Several cross section dimensions were modified to
  achieve the desired results.
                            Example of Modified Cross
                                    Section
                                      Before                                                                                    After
                          Haw Creek     Plan: Plan 01 04/05/2004                                                  Modified Design       Plan: Plan 01 04/08/2004

                           .07        .055             .07                                                     .07              .055                 .07
                 670                                                       Legend                        670                                                         Legend

                 665                                                   EG 100 year                       665                                                       EG 100 year
                                                                       WS 100 year                                                                                 WS 100 y ear




                                                                                      Elevat ion (f t)
Elevation (ft)




                 660                                                       Ground                        660                                                         Ground

                                                                           Bank Sta                                                                                 Bank Sta
                 655                                                                                     655


                 650                                                                                     650


                 645                                                                                     645
                   1000     1100      1200       1300        1400   1500                                   1000       1100     1200           1300   1400    1500

                                        Station (ft)                                                                                Station (f t)
Floodplain Delineation




     Note: Delineation is based on 10 foot contour mapping.
                 Results
• The flow was contained in the channel in the
  area of concern.

• The velocity of the channel decreased in the
  area of modification due to an increase in
  volume that the new channel holds therefore
  erosion is not a concern.

• The land previously in the floodplain can
  now be used for development purposes
  without the risk of flooding based on a 100
  year storm.
             Indian Creek
Area of Study

• Extends upstream
  5.75 miles from the
  convergence with
  the Wabash River to
  join an existing DNR
  study
• Township 23 N,
  Range 5 W,
  Tippecanoe County,
  IN
         Current Situation
• A residential area with bridge is
  threatened

• Design must not interfere with housing
  or local bridge

• Due to steep topography and high
  velocities in the channel, erosion is a
  concern
          Recommendation

• Selective stream bed modifications in
  the surrounding area can alleviate the
  flooding problems without interfering
  with the bridge.

• The addition of vegetation and riprap
  will help decrease erosion.
                 Before and After
                           Indian Creek to Wabash      Plan: plan_new     4/24/2004
                                                       13
                                     .07                    .04     .07
                 610                                                                         Legend

                 600                                                                        EG 100y r
                                                                                            WS 100y r

Elevation (ft)
                 590                                                                         Ground

                                                                                            Bank Sta
                 580


                 570


                 560
                       0     100      200      300          400   500        600      700
                                                Station (f t)


                           Indian Creek to Wabash    Plan: plan_design    4/24/2004
                                                       13
                                     .07                    .04     .07
                 610                                                                         Legend

                 600                                                                        EG 100y r
                                                                                            WS 100y r
Elevation (ft)




                 590                                                                        Crit 100y r

                                                                                             Ground
                 580
                                                                                            Bank Sta

                 570


                 560
                       0     100      200      300          400   500        600      700
                                                Station (f t)
                                  Ind ian Creek to Wabas h              Plan: plan_new

                                           . 07                   .          . 07
                   610                                            0                                Legend
                                                                  4

                   600                                                                             EG 100y r
                                                                                                  W S 100y r
 Elevation (ft)




                   590                                                                            Crit 100y r

                                                                                                    Ground
                   580
                                                                                                   Bank St a

                   570


                   560
                            0      100      200     300          400       500       600     700
                                                     St ation (f t )


                                Indian Creek to Wabash      Plan: plan_design        4/24/2004

                                          . 07                   . 04         . 07
                  610                                                                                   Legend

                  600                                                                                  EG 100y r
                                                                                                       WS 100y r
Elevation (ft)




                  590                                                                                  Crit 100y r

                                                                                                        Ground
                  580
                                                                                                       Bank St a

                  570


                  560
                        0         100      200      300           400       500        600       700
                                                      St ation (f t )
                 Results

• Local houses and pasture land are no
  longer in the flood plain

• Bridge is not at full capacity

• Erosion is keep to a minimum
         Conclusion

As seen in each of the four case
studies, improvements in channel
construction can help contain
floods, reduce erosion, and
optimize usable land.
Any Questions?

				
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