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DSD-INT 2018 Morphodynamic response of Colombian Caribbean beaches under extreme wave events -Cueto

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Presentation by Jairo Cueto, Universidad del Norte, Columbia at the XBeach User Day 2018, during Delft Software Days - Edition 2018. Thursday, 15 November 2018, Delft.

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DSD-INT 2018 Morphodynamic response of Colombian Caribbean beaches under extreme wave events -Cueto

  1. 1. Dpto. Física y Geociencias Morphodynamic response of Colombian Caribbean beaches under extreme wave events Jairo Cueto F., MSc. (student) Barranquilla – Colombia
  2. 2. CONTENTS Background and problem description Justification Methodology Results & discussion Theoretical framework Conclusions
  3. 3. 3 BACKGROUND & PROBLEM DESCRIPTION Colombian Caribbean + 1600 Km of coast SouthAmerica + 11M Inhabitants Tourism & economics Barranquilla, Cartagena, Santa Marta, etc. 7 Caribbean Departments 90% of Colombia’s portuary activity Thousands of tourists per day Colombian Caribbean Coast
  4. 4. 4 BACKGROUND & PROBLEM DESCRIPTION Colombian Caribbean Coast ColombianCaribbean PELIGRODANGER Hurricanes Cold Fronts Northern coast of Colombia costantly in danger because of hurricanes and cold fronts. Coast line changes, beach loss and floodings could be critical. Erosion in Ciénaga Km19 $5M USD Money spent over the last 10 years Erosion in Cartagena $33M USD National plan 2018 Short term morpho changes not widely studied on Colombian Caribbean beaches.
  5. 5. OBJECTIVE General Objective 5 To establish the morphodynamic response of the Colombian Caribbean beaches (Bocagrande, Bocatocino and Costa Verde) to extreme wave events, such as hurricanes and cold fronts. BocatocinoCartagena Ciénaga
  6. 6. JUSTIFICATION 6 Practical uses Decision making and coastal management. Theorical perspective Morphodynamic response of dissipative and intermediate-reflective beaches. Methodological utility Future research. Social importance Communities living near the sea.
  7. 7. Model description: XBeach 7 THEORETICAL FRAMEWORK XBeach based on four routines Wave module wave forcing Flow module water level, current water level, current Sediment module sediment transport Morpho module Bed level
  8. 8. METHODOLOGY 1 Data collection 2 Model calibration and validation 3 Field cases 4 Results analysis 8
  9. 9. 1 Data collection General characterization - Cartagena, Bolívar - Fine sands (0.08 – 0.42 mm) - 2 dry seasons (jun-aug/dec-mar) - 2 wet seasons (apr-may/sep-nov) S = 3° Dissipative Bocagrande Cartagena Bocagrande Images from Google Earth METHODOLOGY 9 [6] Poveda, G. (2004). La hidroclimatología de Colombia. Ciencias de la Tierra 2 x 1 km
  10. 10. 1 Data collection General characterization - Ciénaga, Magdalena - Medium sands (0.42 – 2.00 mm) - 2 dry seasons (jun-aug/dec-mar) - 2 wet seasons (apr-may/sep-nov) S = 7° Reflective/int. Costa Verde Ciénaga Costa Verde Images from Google Earth METHODOLOGY 10 4 x 1 km
  11. 11. 1 Data collection Field campaigns METHODOLOGY AQ4-OBS AQ3 AQ2 RBR AQ1 Costa Verde beach. Image from Google Earth Equipment Distance (m) Distance (m) AQ4 - OBS 3 10 AQ3 19 26 AQ2 180 44 AQ1 321 107 RBR 750 650 CV 11 BG
  12. 12. 1 Data collection Variables characterization METHODOLOGY Field campaigns composition: 4 days – 96 sea states – 5 sensors per beach S4S3S2S1RBR BG_RBR_EH_D1_E16 BG: Bocagrande beach RBR: Equipment EH: Wet season D1: Day #1 E16: Sea state #16 (3-4 p.m.) P Vx Vy 12
  13. 13. 1 Data collection Variables characterization METHODOLOGY P Vx Vy FFT Low & high frequencies IG SS Hs Coastal currents 13
  14. 14. XBeach METHODOLOGY 2 Model calibration and validation Sensitivity analysis Default profile Distance till shore (m) Waveheight(m) Wave variation Cell size Friction Viscosity Gamma Smag. 0.1 – 0.7 m2/s 40 – 70 m1/2/s 0.5 – 2.0 m 3 – 20 14
  15. 15. XBeach METHODOLOGY 2 Model calibration and validation Hydro-validation Beach profile Distance till shore (m) Waveheight(m) Wave variation : Measured data 96 sea states 2 seasons 2 beaches 5 sensors x 1920 Hs validation points Forcing XB with RBR data 15
  16. 16. XBeach METHODOLOGY 2 Model calibration and validation Hydro-validation Beach profile Distance till shore (m) Waveheight(m) Wave variation : Measured data Forcing XB with RBR data 160SEA STATES modeled 40 40 40 40 CV-EH CV-ES BG-EH BG-ES 16
  17. 17. XBeach METHODOLOGY 2 Model calibration and validation Morpho-validation Beach profile Distance till shore (m) Waveheight(m) Wave variation Modeled profile Forcing XB with SWAN data Storm profile Storm profile measured Storm profile modeled VS 17
  18. 18. METHODOLOGY 2 Model calibration and validation SWAN Sensitivity analysis Bathymetry Distance near shore (m) Waveheight(m) Wave variation XB Profile starting point 18 Cell size Friction Hindcast winds White-capping
  19. 19. METHODOLOGY 2 Model calibration and validation SWAN Sensitivity analysis Bathymetry Distance near shore (m) Waveheight(m) Wave variation XB Profile starting point VALIDATION Hs at XB Profile starting point Hs measured with RBR VS 19
  20. 20. METHODOLOGY 2 Model calibration and validation SWAN Costa Verde - Forced with buoys data - Outcome: Hs SignificantWaveheight(m) XB Profile starting point Wave propagation 20 Example
  21. 21. Wave reanalysis data METHODOLOGY BV07 Atlántico Bolívar BV09 BV10 Magdalena Colombian Central Caribbean Virtual buoys of reanalysis: WW3 generated Exteme wave regime construction Wave series extraction (1979-2018) 21 3 Field cases
  22. 22. METHODOLOGY Extreme events impact 3 Field cases HURRICANES COLD FRONTS Hurricane X Hs | Tp | Dm X days: modelling time X days: modelling time BG 22 Cold front X Hs | Tp | Dm BT CV
  23. 23. METHODOLOGY Morpho changes 4 Results analysis Waveheight(m) Distance till shore (m) SS wave height IG wave height Initial bed level Final bed level WAVE ACTION INDUCED (extreme events)XB – 1D Submerged formations Slope changes: profile configuration Beach loss/ Coast line advance Beach loss: Land lost by wave action Slope changes: New breaking parameters Submerged formations: Bars 23
  24. 24. METHODOLOGY Hydro analisys 4 Results analysis WAVE HEIGHT & CURRENTS 24 SS wave height (modelled) IG wave height (modelled) SS wave height (measured) IG wave height (measured) Waveheight(m) Distance till shore (m) XB Flowvelocity Distance till shore (m) XB Depthaveraged Depth averaged flow velocity (modelled) Depth averaged flow velocity (measured) 0 0
  25. 25. 25 RESULTS & DISCUSSION A XBeach calibration & validation B Field cases
  26. 26. XBeach Costa Verde Dry season Hs = 0.89 m 26 A XBeach calibration and validation RESULTS & DISCUSSION Costa Verde Wet season Hs = 0.52 m ES-D1-E19EH-D3-E18
  27. 27. XBeach Bocagrande Dry season Hs = 2.02 m 27 A XBeach calibration and validation Bocagrande Wet season Hs = 0.72 m RESULTS & DISCUSSION
  28. 28. Skill Scores: Costa Verde CV-ES S1 S2 S3 R2 0.8762 0.8568 0.8114 Bias -0.0109 -0.0012 -0.0123 Willmott 0.9629 0.9562 0.9391 28 A XBeach calibration and validation Sensor 1 Sensor 1 CV-EH S1 S2 S3 R2 0.8672 0.8368 0.8313 Bias -0.0412 -0.0432 -0.0154 Willmott 0.8993 0.8732 0.8692 Wet season Dry season RESULTS & DISCUSSION
  29. 29. Skill Scores: Bocagrande 29 A XBeach calibration and validation Sensor 1 Wet season Sensor 1 Dry season BG-ES S1 S2 S3 R2 0.9070 0.8804 0.8425 Bias 0.0127 -0.0083 -0.0350 Willmott 0.9720 0.9482 0.8324 BG-EH S1 S2 S3 R2 0.8872 0.8801 0.8214 Bias -0.0312 -0.0377 -0.0371 Willmott 0.8996 0.8812 0.8414 RESULTS & DISCUSSION
  30. 30. Colombian Central Caribbean Wave reanalysis data Hurricanes Hs (m) Tp (s) Dm (°) Joan (1988) 0.60 8.28 48.85 Bret (1993) 1.64 9.62 31.51 Julio (1996) 1.64 8.86 28.02 Mitch (1998) 0.83 8.08 273.43 Lenny (1999) 2.74 9.60 299.11 Sandy (2009) 1.21 8.93 276.66 Matthew (2016) 3.20 14.12 29.62 BV07 Most significant extreme events HURRICANES COLD FRONTS Ciénaga Cold Fronts 2009 2017 30 CiénagaB Field cases RESULTS & DISCUSSION
  31. 31. Colombian Central Caribbean Wave reanalysis data Most significant extreme events HURRICANES COLD FRONTS Ciénaga Cold Fronts 2009 2017 31 Cold Fronts Hs (m) Tp (s) Dm (°) Cold front (2009) 2.17 9.09 29.69 Cold front (2017) 1.52 8.05 34.15 BV07 Ciénaga Hurricanes Joan Bret Julio Mitch Lenny Sandy Matthew B Field cases RESULTS & DISCUSSION
  32. 32. Hurricanes Hs (m) Tp (s) Dm (°) Joan (1988) 1.63 6.82 244.31 Bret (1993) 1.89 7.41 26.93 Julio (1996) 1.13 9.69 33.3 Mitch (1998) 1.62 6.24 249.45 Lenny (1999) 2.77 9.24 308.27 Sandy (2009) 1.96 6.72 256.06 Matthew (2016) 2.06 14.12 29.62 Colombian Central Caribbean Wave reanalysis data BV10 Most significant extreme events HURRICANES COLD FRONTS Cartagena Cold Fronts 2009 2017 32 CartagenaB Field cases RESULTS & DISCUSSION
  33. 33. Colombian Central Caribbean Wave reanalysis data Most significant extreme events HURRICANES COLD FRONTS Cartagena Cold Fronts 2009 2017 33 Cold Fronts Hs (m) Tp (s) Dm (°) Cold front (2009) 2.61 9.07 28.34 Cold front (2017) 3.53 9.14 35.79 BV10 Cartagena Hurricanes Joan Bret Julio Mitch Lenny Sandy Matthew B Field cases RESULTS & DISCUSSION
  34. 34. Costa Verde 34 RESULTS & DISCUSSION B Field cases SS wave height IG wave height Initial bed level Final bed level Cold Front 2009 Lenny 1999 Matthew 2016 Profile remains stable: Reflective S = 7° Beach loss: Cold front – 11 m ; Lenny – 13 m ; Matthew – 9 m Bar begining A B C A B C A B C A B C
  35. 35. Bocagrande 35 RESULTS & DISCUSSION B Field cases SS wave height IG wave height Initial bed level Final bed level Cold Front 2017 Lenny 1999 Matthew 2016 Cold front – no bar ; Lenny – bar beggining ; Matthew – bar beggining Beach loss: Cold front – 54 m ; Lenny – 41 m ; Matthew – 40 m Storm profile: +disspative A B C A B C A B C A C B
  36. 36. CONCLUSIONS Bocagrande’s morphodynamic is heavily affected by extreme wave events, losing large amounts of sediment. This fact occurs because waves in Bocagrande tend to be more energetic than in Costa Verde, where wave height is lower due to refraction and diffraction effects when approaching the coast. Under extreme wave conditions, beach loss in Bocagrande could be critical (+50 m) causing severe dune erosion and floods, affecting the community living by the sea. The own intermediate- reflective nature of Costa Verde’s beach profile provides a shield for this area under extreme wave events. A significant portion of the wave energy is dissipated through breaking and the morphological structure remains stable. Beach loss for Costa Verde cases is not critical (+10 m).
  37. 37. ACKNOWLEDGEMENTS Geo4 37 Jairo Cueto, MSc. (Student) Universidad del Norte jecueto@uninorte.edu.co

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