Field Observations of a Multilevel Beach Cusp System and Their Swash Zone Dynamics
Abstract
:1. Introduction
2. Beach Cusp Evolution
2.1. Beach Cusp Predictions
2.2. Multilevel Beach Cusp System
- To quantify four different cusp parameters (i.e., Cusp Spacing, Cusp Elevation, Cusp Amplitude, and Cusp Depth) of a three-tiered cusp system during a six-month period;
- To link their change over time with the hydrodynamics occurring in the study area;
- To provide insightful information regarding the current predictive formulations for cusp spacing;
- To formulate new predictive theories for the other cusp parameters (i.e., Cusp Elevation, Cusp Amplitude, and Cusp Depth).
3. Methodology
3.1. Study Area
3.2. Hydrodynamics
3.3. UAV Survey Method
4. Results
4.1. Hydrodynamics
4.2. Cusp Parameters
4.3. Beach Cusp Predictions
4.3.1. Lower Beach Level Cusps
4.3.2. Mid Beach Level Cusps
4.3.3. Upper Beach Level Cusps
4.4. Prediction Theory Cusp Parameters
5. Discussion
5.1. Cusp Parameters
5.2. Beach Cusp Predictions
5.3. Multilevel Beach Cusp System
6. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Sampling Setup 730D Valeport | ||
---|---|---|
Parameter | Value | Unit |
Rate | 1 | Hz |
Tide Burst Duration | 20 | Seconds |
Tide Burst Interval | 60 | Minutes |
Wave Burst Duration | 1024 | Samples |
Wave Burst Interval | 60 | Minutes |
Statistical Parameters Model Validation | |||
---|---|---|---|
Wave Parameter | R | RMSE | Bias |
Hs | 0.919 | 0.401 | 0.081 |
Tp | 0.840 | 1.005 | 0.129 |
Overview Cusp Parameters | ||||||
---|---|---|---|---|---|---|
Date | Level | Cusp Spacing (m) | Cusp Amplitude (m) | Cusp Elevation (m) | Cusp Depth (m) | |
1 | 26 March | Upper Beach | 39.9 | 0.86 | 5.41 | 16.91 |
Mid Beach | 38.5 | 0.58 | 3.14 | 16.57 | ||
Low Beach | - | |||||
2 | 10 April | Upper Beach | 40.3 | 0.83 | 5.46 | 15.01 |
Mid Beach | 24.6 | 0.34 | 2.81 | 12.31 | ||
Low Beach | 11.5 | 0.25 | 1.91 | 9.87 | ||
3 | 11 April | Upper Beach | 39.2 | 0.87 | 5.62 | 14.98 |
Mid Beach | 25.0 | 0.43 | 2.76 | 12.69 | ||
Low Beach | - | |||||
4 | 01 May | Upper Beach | 38.9 | 1.05 | 4.87 | 15.67 |
Mid Beach | 14.9 | 0.21 | 2.33 | 9.06 | ||
Low Beach | 11.6 | 0.32 | 2.08 | 6.01 | ||
5 | 03 May | Upper Beach | 37.7 | 0.81 | 5.69 | 13.24 |
Mid Beach | 12.8 | 0.23 | 2.42 | 8.81 | ||
Low Beach | 12.3 | 0.04 | 1.03 | 2.73 | ||
6 | 10 May | Upper Beach | 37.9 | 0.79 | 5.68 | 12.32 |
Mid Beach | 19.9 | 0.29 | 2.96 | 8.55 | ||
Low Beach | 16.5 | 0.18 | 1.82 | 8.97 | ||
7 | 17 May | Upper Beach | 40.9 | 0.86 | 5.71 | 15.94 |
Mid Beach | 19.7 | 0.36 | 3.01 | 8.48 | ||
Low Beach | - | |||||
8 | 20 May | Upper Beach | 40.9 | 0.86 | 5.72 | 15.40 |
Mid Beach | 19.7 | 0.42 | 2.99 | 8.62 | ||
Low Beach | - | |||||
9 | 06 June | Upper Beach | 40.8 | 0.86 | 5.73 | 15.39 |
Mid Beach | 11.1 | 0.22 | 2.68 | 15.14 | ||
Low Beach | - | |||||
10 | 14 June | Upper Beach | 40.9 | 0.84 | 5.72 | 15.02 |
Mid Beach | 12.2 | 0.71 | 3.47 | 15.42 | ||
Low Beach | 11.8 | 0.13 | 1.15 | 5.39 | ||
11 | 18 June | Upper Beach | 40.2 | 0.84 | 5.81 | 15.47 |
Mid Beach | 15.1 | 0.31 | 3.04 | 8.06 | ||
Low Beach | 7.4 | 0.15 | 2.14 | 7.54 | ||
12 | 21 June | Upper Beach | 40.9 | 0.85 | 5.74 | 15.53 |
Mid Beach | 16.3 | 0.39 | 2.64 | 8.35 | ||
Low Beach | 9.9 | 0.09 | 1.41 | 11.61 | ||
13 | 24 June | Upper Beach | 40.9 | 0.84 | 5.68 | 15.35 |
Mid Beach | 17.0 | 0.40 | 2.51 | 11.43 | ||
Low Beach | 16.7 | 0.22 | 1.71 | 7.39 | ||
14 | 25 June | Upper Beach | 40.8 | 0.83 | 5.74 | 17.21 |
Mid Beach | 17.1 | 0.42 | 2.73 | 11.36 | ||
Low Beach | 11.6 | 0.14 | 1.62 | 4.75 | ||
15 | 25 June | Upper Beach | 40.8 | 0.83 | 5.67 | 17.25 |
Mid Beach | 17.2 | 0.44 | 2.57 | 11.49 | ||
Low Beach | 11.8 | 0.16 | 1.73 | 4.50 | ||
16 | 02 July | Upper Beach | 40.8 | 0.84 | 5.71 | 14.93 |
Mid Beach | 17.4 | 0.47 | 2.68 | 10.60 | ||
Low Beach | - | |||||
17 | 03 July | Upper Beach | 40.8 | 0.85 | 5.69 | 15.35 |
Mid Beach | 17.3 | 0.48 | 2.68 | 10.85 | ||
Low Beach | 6.5 | 0.18 | 1.84 | 6.96 | ||
18 | 04 July | Upper Beach | 40.9 | 0.83 | 5.69 | 15.06 |
Mid Beach | 17.4 | 0.47 | 2.64 | 10.71 | ||
Low Beach | 9.0 | 0.30 | 1.86 | 5.01 | ||
19 | 16 July | Upper Beach | 40.8 | 0.85 | 5.71 | 15.21 |
Mid Beach | 17.6 | 0.42 | 2.74 | 10.73 | ||
Low Beach | 12.9 | 0.15 | 1.92 | 7.48 | ||
20 | 31 July | Upper Beach | 40.7 | 0.85 | 5.80 | 15.36 |
Mid Beach | 19.2 | 0.32 | 2.6 | 11.04 | ||
Low Beach | 10.2 | 0.07 | 1.11 | 2.0 | ||
21 | 01 Aug | Upper Beach | 40.8 | 0.85 | 5.79 | 15.41 |
Mid Beach | 19.7 | 0.30 | 2.57 | 10.22 | ||
Low Beach | - | |||||
22 | 28 Aug | Upper Beach | 39.4 | 0.78 | 5.61 | 16.39 |
Mid Beach | 15.2 | 0.55 | 3.06 | 7.68 | ||
Low Beach | 6.7 | 0.18 | 1.21 | 7.66 | ||
23 | 13 Sept | Upper Beach | 40.8 | 0.85 | 5.73 | 15.37 |
Mid Beach | 13.0 | 0.33 | 3.03 | 8.50 | ||
Low Beach | - |
Statistical Analysis Cusp Spacing | |||
---|---|---|---|
Mean (m) | Standard Deviation (m) | Coefficient of Variation | |
Upper beach level | 40.26 | 0.95 | 0.02 |
Mid beach level | 18.17 | 5.48 | 0.30 |
Low beach level | 11.09 | 2.91 | 0.26 |
Performance Cusp Spacing Predictions | ||||
---|---|---|---|---|
Theory | RMSE (m) | r2 | Equation | Fitting Coefficient |
Edge-Wave Theory | 4.78 | 0.087 | m = 0.4845 | |
Self-Organisation Theory | 2.03 | 0.642 | f = 1.1628 | |
Sunamura (2004) | 2.37 | 0.473 | A = 0.7032 |
Resulting Hydrodynamics for Mid Beach Level Cusps | ||||
---|---|---|---|---|
Survey | Date | Observed Cusp Spacing (m) | Predicted Self Organisation (m) | Occurrence |
1 | 26 March | 38.48 | 37.81 | 03/03/2019T00:00 |
2 | 10 April | 24.64 | 22.90 | 09/04/2019T04:00 |
3 | 11 April | 25.05 | 23.22 | 11/04/2019T08:00 |
4 | 01 May | 14.97 | 14.97 | 30/04/2019T18:00 |
5 | 03 May | 12.84 | 12.27 | 01/05/2019T08:00 |
6 | 10 May | 19.90 | 20.04 | 09/05/2019T10:00 |
7 | 17 May | 19.71 | 19.63 | 16/05/2019T10:00 |
8 | 20 May | 19.68 | 19.63 | 16/05/2019T10:00 |
9 | 06 June | 11.15 | 11.89 | 04/06/2019T06:00 |
10 | 14 June | 11.19 | 11.24 | 13/06/2019T14:00 |
11 | 18 June | 15.07 | 12.03 | 16/06/2019T22:00 |
12 | 21 June | 16.31 | 12.85 | 19/06/2019T22:00 |
13 | 24 June | 17.05 | 17.45 | 23/06/2019T18:00 |
14 | 25 June | 17.12 | 17.45 | 23/06/2019T18:00 |
15 | 25 June | 17.15 | 17.45 | 23/06/2019T18:00 |
16 | 02 July | 17.37 | 17.45 | 23/06/2019T18:00 |
17 | 03 July | 17.31 | 17.45 | 23/06/2019T18:00 |
18 | 04 July | 17.39 | 17.45 | 23/06/2019T18:00 |
19 | 16 July | 17.55 | 15.63 | 15/07/2019T20:00 |
20 | 31 July | 19.23 | 20.74 | 25/07/2019T22:00 |
21 | 01 Aug | 19.65 | 20.74 | 25/07/2019T22:00 |
22 | 28 Aug | 15.19 | 18.91 | 27/08/2019T19:00 |
23 | 13 Sept | 13.01 | 16.79 | 13/09/2019T05:00 |
Prediction Cusp Parameters | ||||
---|---|---|---|---|
Parameter | Equation | Fitting Coefficient | RMSE (m) | R |
Cusp Elevation | ne = 0.171 | 0.585 | 0.810 | |
Cusp Depth | nd = 0.636 | 2.998 | 0.648 | |
Cusp Amplitude | na = 0.023 | 0.124 | 0.697 |
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Nuyts, S.; Li, Z.; Hickey, K.; Murphy, J. Field Observations of a Multilevel Beach Cusp System and Their Swash Zone Dynamics. Geosciences 2021, 11, 148. https://doi.org/10.3390/geosciences11040148
Nuyts S, Li Z, Hickey K, Murphy J. Field Observations of a Multilevel Beach Cusp System and Their Swash Zone Dynamics. Geosciences. 2021; 11(4):148. https://doi.org/10.3390/geosciences11040148
Chicago/Turabian StyleNuyts, Siegmund, Zili Li, Kieran Hickey, and Jimmy Murphy. 2021. "Field Observations of a Multilevel Beach Cusp System and Their Swash Zone Dynamics" Geosciences 11, no. 4: 148. https://doi.org/10.3390/geosciences11040148