There are a number of parallels between the two rivers as indeed there are by many other rivers since the end of the ice age. they have all been subject to the sea levels into which they decant having risen at stages by a total of 60 metres. this, in turn has affected their gradients resulting in meanders, deposition of aluvium and a wide basin of 'wetlands' which have only been constrain within banks in historical times.
Since the industrial revolution, this containment has been by sheet piles but prior to this, largely in a piecemeal fashion often by beaching old hulls at high tide, filling them with, usually rubbish and the land on the foreshore behind to form an impromptu jetty.
I know this because I have worked at London Docklands redevelopment as an engineer in the 80s and before this in planning pumping works for Chatham to contain abnormal tide and river levels.
Over the years, I became aware of succeeding raised wetlands found by a geographer Dr Devoy who presented a paper in 1979 to the Royal Society. He calls these levels Tilbury I- IV, the highest two of which, Tilbury III and IV being in the neolithic and bronze age respectively. Tilbury being where he found the levels of marine and organic materials which could be dated
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Since then, and largely due to recent planning legislation (PPG16), these levels have offered up habitations such as crannogs and trackways. Strangely enough, some have been found at planned new Tesco supermarkets where a large site is necessary at for instance at Dagenham and Rainham, also in Docklands at Beckton.
The use of old boats as wharfage may be much earlier than would be imagined- at Govan General Terminus, a number of early boats have been found in a line behind the current river walls. Also at Southampton and Hull. I may have cut through one myself in 1955 at general Terminus as a young student apprentice with British Railways in digging a main drain for a new ore bunker there!
Other well known examples are in New York on the Hudson found in the seventies and another one recently at the redevelopment of the World Trade Centre site.
Looking at the Clyde, The presence of a number of islands downstream of Glasgow is well known, the former crannogs on the foreshore and old maps show that the river had wetlands on either side, see the convoluted course of the Molendinar south of Duke Street and the Clyde's meanders upstream of this.
John