Pagham Lagoon Sluice

A Memory of Pagham.

I'm not a Pagham local but have visited the place many times over the last 20 or so years.  I've always been intrigued by that old concrete structure at the southeast tip of Pagham Lagoon but have been unable to find a definitive answer as to its age or purpose.  

The most likely suggestion I've received is that it was a sluice built around 1876 when Pagham Harbour was reclaimed and sealed off from the sea (although as we all know, this reclamation only lasted until December 1910 when the sea broke in again).  

My understanding is that the Lagoon was originally the entry channel between the sea and the rest of Pagham Harbour, with the seaward outlet being at what is now the northeastern tip of the Lagoon.  This means that prior to 1876 the Lagoon and Harbour were not separated as they are now, and small vessels used both to reach the quay at Sidlesham in the days when its Mill was still operating.

Presumably the sluice in the Lagoon was built to assist in the drainage of the Lagoon and Harbour under the 1876 scheme........  but does anybody have more detail as to how this concrete structure actually functioned as a sluice and how the outfall was directed into the sea?  

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