Morphodynamics of Non-Estuarine Rivermouth Lagoons on High- Energy Coasts
- Author
- Hart, D.E.
- Year
- 2009
- Journal / Source
- Journal of Coastal Research
- Volume
- SI 56
- Pages
- 1355-1359
- Summary
- The rivermouth lagoons of high-energy temperate coasts are physically complex and highly-dynamic systems. They are also ecologically productive and socio-economically valuable. Compared to the extensive literature on estuaries, relatively little has been published on these predominantly-freshwater lagoons, especially where they occur on coarse-sediment coasts. Contemporary development and management pressures worldwide necessitate greater understanding of their functioning and future. This paper analyzes observations from a spectrum of nonestuarine lagoons at the interface between high-energy mixed sand and gravel beaches and braided to meandering rivers in eastern New Zealand. Analyses reveal key characteristics which prove useful in predicting lagoon behavior. These include the balance between river flows, wave energy and barrier morphology that, in turn, causes variation in lagoon outlets and extents over flood and storm cycles; relationships between river scale and lagoon dynamics; and lagoon vulnerability to modification. Findings are summarized in a new rivermouth lagoon model which may be used, alongside local climate and catchment data, to understand the present and future states of non-estuarine rivermouth lagoons on high-energy coarse-sediment coasts internationally.