Skip to page content

FSC logo
The Seashore

Rocky Shore Trail
Did you know the FSC publishes fold out charts and guides? Find out more.

Tidal Diagram

Tidal zone diagram

The precise heights of these zones will depend on where you are. All tidal heights are measured from a local datum point (Chart Datum). Effectively this is the lowest the tide ever gets and is called 0 metres (or whatever unit you are using) For Milford Haven (where Dale Fort is in West Wales) the heights on the diagram are as follows:

ExtremeLowWaterSprings = 0.0m.............MeanLowWaterNeaps = 2.5m................

MeanHighWaterSprings = 5.2m................Extreme HighWaterSprings = 7.8m

Mid-Tide point therefore, 3.9 metres above chart datum

Tidal Heights Chart

The bits of shore covered by the water EHWS to ELWS we call the littoral zone. The bit below the lowest tides we call the sub-littoral zone. The dramatic environmental changes that occur from over the small physical space from the bottom to the top of the shore result in a massive variety of organisms all crammed into this small space. People sometimes say that (in terms of changes in environmental conditions) moving from the bottom to the top of the shore is like moving from the equator to the poles in terrestrial environments.

Looking for a next step?
The FSC offers a range of publications, courses for schools and colleges and courses for adults, families and professionals that relate to the seashore environment. Why not find out more about the FSC?

Do you have any questions?

Copyright © 2008 Field Studies Council  
Creative Commons License
Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 Licence

Site Statistics by Opentracker