Concept
Emergence regime changes - local, including tidal level change considerations
| URI | http://vocab.nerc.ac.uk/collection/M14/current/H4/1/ | ||
|---|---|---|---|
| Within Vocab | OSPAR list of defined pressures on the marine environment | ||
| Alternative Labels | |||
| Definition | Changes in water levels reducing the intertidal zone (and the associated/dependant habitats). The pressure relates to changes in both the spatial area and duration that intertidal species are immersed and exposed during tidal cycles (the percentage of immersion is dependant on the position or height on the shore relative to the tide). The spatial and temporal extent of the pressure will be dependant on the causal activities but can be delineated. This relates to anthropogenic causes that may directly influence the temporal and spatial extent of tidal immersion, e.g. upstream and downstream of a tidal barrage the emergence would be respectively reduced and increased, beach re-profiling could change gradients and therefore exposure times, capital dredging may change the natural tidal range, managed realignment, saltmarsh creation. Such alteration may be of importance in estuaries because of their influence on tidal flushing and potential wave propagation. Changes in tidal flushing can change the sediment dynamics and may lead to changing patterns of deposition and erosion. Changes in tidal levels will only affect the emergence regime in areas that are inundated for only part of the time. The effects that tidal level changes may have on sediment transport are not restricted to these areas, so a very large construction could significantly affect the tidal level at a deep site without changing the emergence regime. Such a change could still have a serious impact. This excludes pressure from sea level rise which is considered under the climate change pressures. | ||
| Date | 2015-09-11T13:08:16 | ||
| Identifier | SDN:M14::H4 | ||
| Note | accepted | ||
| Is Version Of | H4 | ||
| version | 1 | ||
| Broader | M15:H |
Hydrological changes (inshore/local) | |
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