Cardiff Bay Barrage

This aerial picture shows Cardiff Bay Barrage lock and sluice gates, with Penarth Marina and Yacht club. The Bay is an amazing structure. Here's some interesting facts......

Cardiff Bay is a sheltered freshwater bay covering about 200 hectares on the Bristol Channel at the mouths of the Rivers Taff and Ely.
The Cardiff Bay Barrage itself is 1.1km long and extends from Cardiff docks in the north to Penarth in the south. This major civil engineering construction project subsequently led to the impoundment of the bay that has over 13km of waterfront.
This 120 million pound project (commenced in 1987) was the catalyst for the 2 billion pound regeneration of the old docklands areas of Cardiff and Penarth.
The Bristol Channel boasts the second highest tidal range in the world, with over 14metres between high and low tides. The Outer Harbour provides a safe haven for vessels to shelter from storms in the Bristol Channel and can hold up to 200 small vessels. 

Locks and Bridges
There are 3 locks on the Barrage. Each lock is 40 metres long; two are 8metres wide and one is 10.5metres wide. The locks allow boats to navigate between the Severn Estuary and Cardiff Bay. Each lock has a bascule bridge weighing approximately 88 tonnes.When they are closed these allow passage over the barrage structure for pedestrians and vehicles. 
Sluice Gates
There are 5 sluice gates that control the level of water in the Bay. Each sluice gate is 9metres wide and 7.5metres high. When the estuary level is higher than the Bay level the sluices close to prevent seawater entering the freshwater lake. When the estuary level is lower than the Bay level the sluice gates open to maintain a preferred level of water in the Bay.
Fish Pass
The Barrage incorporates a specially designed fish pass to allow salmon and sea trout to return to the Rivers Taff and Ely. It is one of the most  advanced of its kind in Europe. Underwater cameras, motion and audio equipment record their passage through the Fish Pass.