Thanks to SNH for giving permission for this earthcache
Please note that the sand and mudflats at the edge of the Clyde form part of the Inner Clyde Special Protection Area, which has been designated to protect the internationally important population of migratory birds which feeds and roosts there during the winter months. We would therefore request that all dogs be kept on a leash in this area during the months of September to April inclusive. Many thanks. YOU DO NOT HAVE TO WALK ON THE MUD FLATS TO OBTAIN THE ANSWERS.
Mud Flats (also referred to as tidal flats) are coastal wetlands that form when mud is deposited by tides or rivers. If the coastal sediments are fine (ie. silt and clay), a mud flat is developed instead of a beach. Flats are typically found in areas where the tidal waters flow slowly, such as sheltered bays, estuaries and gently shelving coasts.
A mixture of very fine silts from tidal waters and loose, unconsolidated soil or sediment from rivers dropping their load as they reach the sea, is deposited, causing a build-up of mud layers. Mud flats are covered at high tide and exposed as the tide drops. The flats always contain winding channels that remain open by tidal action. Unless fed by active water sources, such as streams, they will normally dry out at low tide and contain no water.
Salt Marshes form in coastal areas that already have mud flats. They form in the higher Intertidal/Supratidal* zone. Marshes are exposed at low tide and only partially flooded at high tide, so only salt resistant forms of vegetation can grow. They are usually flat with muddy channels or holes in them. When the tide rises gently, it brings sediment into the marsh and deposits it before retreating.
The size of the particles of sediment that make up a beach are usually a reflection of the energy of the waves that hit the shore. In low-energy environments, such as estuaries, we see very fine particles such as silt or mud deposited. Higher-energy beaches are often characterised by larger particles, such as pebbles or even boulders.
Mud Flats and Salt Marshes are much undervalued because they tend not to be seen to be useful for recreation, but they are a vital habitat for many organic materials, juvenile fish such as plaice and are a vital habitat for wintering waders and wildfowl. They also provide a valuable sea defence by absorbing wave energy therefore protecting the inland landforms from erosion. The loss of the mud flats would make the coastal area vulnerable to erosion and flooding.
*Tidal flats have 3 environments
Subtidal – below low tide and seldom exposed. Sediment is usually sand.
Intertidal - lies between low and high tides and is exposed once or twice daily. The middle part of this is covered for about half of the tidal cycle. Sediment is usually a mixture of mud and sand.
Supratidal - above high tide and is exposed most of the time with flooding only during spring or storm tides. This zone is divided into vegetated (salt marshes) and non-vegetated (mud flats). Sediment is usually mud.
To log this EarthCache, go to the listed coordinates and carry out the following tasks. The answers MUST be sent to us via email or message. IF ANSWERS ARE NOT RECEIVED WITHIN 4 WEEKS OF LOGGING IT WILL BE DELETED WITHOUT NOTIFICATION.
- Examine and describe the sediment at Stage 1 (EC coords).
- Examine and describe the sediment at Stage 2.(colour, texture, is it hard or soft)
- Why would there be a difference between these two points?
- The river channel is continuously dredged to allow for a deep channel for shipping. Do you think the river current would keep it free from sediment if this didn’t happen? Please provide a reason to back up your answer.
- Please attach a photo to your log of you, your dog, gps, thumb or something personal to prove you were here. Please do not show any spoilers in your photo.
June 2019 the logging tasks for EC were updated. COs can now insist on a photo as proof of visit.
If you want to walk out to the towers, you can continue out from waypoint 2, but ENSURE YOU HAVE CHECKED THE TIDE TABLES FIRST.
https://www.tidetimes.org.uk/bowling-tide-times
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