A regional analysis of tide-surge interactions during extreme water levels in complex coastal systems of Aotearoa New Zealand
- Author
- Costa, W., Bryan, K.R., Stephens, S.A. Coco, G.
- Year
- 2023
- Journal / Source
- Frontiers in Marine Science
- Volume
- 10
- Number
- 1170756
- Pages
- 21 pp.
- Summary
- Tide-surge interaction (TSI) is a critical factor in assessing flooding in shallow coastal systems, particularly in estuaries and harbours. Non-linear interactions between tides and surges can occur due to the water depth and bed friction. Global investigations have been conducted to examine TSI, but its occurrence and impact on water levels in Aotearoa New Zealand (NZ) have not been extensively studied. Water level observations from 36 tide gauges across the diverse coast of NZ were analysed to determine the occurrence and location of TSI. Statistical analysis and numerical modelling were conducted on data from both inside and outside estuaries, focusing on one estuary (Manukau Harbour) to determine the impact of TSI and estuarine morphology on the co-occurrence rate of extreme events. TSI was found to occur at most sites in NZ and primarily affects the timing of the largest surges relative to high tide. There were no regional patterns associated with the tide, non-tidal residual, or skew-surge regimes