Cardiff Bay Barrage 2008
Hold back the tide.
Cardiff Bay is formed at the confluence of the Taff and Ely rivers. Just after joining and forming the bay, they spill
into the Brisol Channel, the estuary of the River Severn. Being a tidal area, the bay would empty and fill twice each day,
being used for pleasure boat trips at high tide, and serving the wading birds with the extensive mudflats at low tide.
Humans, however, can be selfish. Low tide was deemed ugly, and prevented tourist boats from using the bay. Supposedly, this
reduced the amount of tourism in the area relating to other local attractions.
Between 1994 and 1999, a barrage was built to keep the bay filled at all times, and aeration diffusers were added to
avoid killing the various forms of aquatic life that needed the natural aeration of the tide. I feel very conflicted about this.
I have to admit that it looks better, and sure, the non-wading birds wil thrive. But humans mess about enough with
the environment already. Why can't we leave things alone? Why must we throw off the natural balance to satisfy our own
asthetic tastes? Should we drive off wading birds and promote non-waders because we like their habitat better?
What about the shellfish that live in the mudflats, the animals that rely on the salt from the tidal wash, or any of the other
animals that I have just overlooked?
In any case, the barrage itself is a truly impressive feat of engineering, and it is the engineering we will see today.
- On the edge of Penarth - a town that will soon be swallowed by Cardiff - is the marina, and some of the most expensive housing. Those without their own boat need not apply.
- The old Penarth Custom House, from when this was a thriving sea port. Not any more.
- The spoiled beauty of the Penarth Cliffs - mostly shale at this point.
- As well as being the longest river in Britain, the river Severn is by far the widest river estury in Britain, at over 90 miles (170 kilometres) between the tip of Wales, and the tip of Cornwall. It is 45 miles (75 kilometres) at the narrow point of the river mouth, seen here. In the middle are the Flat Holm and Steep Holm islands. This estuary has the second highest tidal range in the World, at 15 metres. The rising tide combined with the funnel shaped estuary causes a phenomenon known as the Severn Bore, where a wall of water up to 3 metres high rushes upstream at a maximum of 13 MPH (21 KPH) for 21 miles (33 KM).
- Coot on the bay.
- Sailing at low tide.
- Failing at low tide.
- The main part of the barrage.
- The barrage begins with 3 cantilever bridges, that can be raised to allow shipping to pass underneath.
- The shipping channels pass through this large sea defence wall to enter the estuary.
- Colour scheme.
- The shipping channels all have these impressive lock gates, powerful enough to hold back 15 metres of water depth.
- Pistons used to open and close the lock gate.
- Ok, nearly hold it all back, not quite. There are also large amounts of water ejected under the gates, causing swells in the lagoon.
- Crane. No idea what it does here. Don't ask.
- The heads of the sluice gates.
- Not all of the sluices are in use today, perhaps they wait for higher water levels.
- One of the sluices is in use, and is the main outflow from the Taff and Ely rivers. Without the sound and smell, it doesn't seem all that impressive in a picture.
- Sluice outflow.
- Weirs in a side channel. Presumably this can be used to allow salmon to head upstream for spawning.
- The longest part of the barrage is a grassy bank, tarted up to look supposedly pretty, though far too artificial.
- An eco-friendly wind turbine. Eco-friendly. In a place where the entire natural development has been drastically altered by humans. Very eco-friendly, yeah.
- The other side facing out towards England is significantly more ugly. Who cares what they see from out there, eh?
- Geodes in the rocks.
- Doorway to the docks which once served as the most productive coal exporter in the World.
- Posts that probably do something useful for humans, but also serve as landing platforms for cormorants.
- Dock wall.
- A small tribute to the coal industry.