[1] He built toll houses and charged travellers using his causeway, more than a mile south of the existing bridge at Boldre.

[2] In 1795 the mud building up in the estuary "has rendered it already very narrow; and will probably in a few years, so completely choke it up, as to make it unnavigable by any ships of considerable burden.

[2] Today silting in the harbour as a result of the structure (almost a dam) occurs, but is ameliorated a higher sea level and the scouring effects of the Isle of Wight ferries.

[4] Against the sea, the outer limit of the end of the estuary's mud at low tide is 550–650 metres closer to land than in 1895.

There are several components that are used to determine this, including biological status, which looks at the quantity and varieties of invertebrates, angiosperms and fish.