Where did all the water go?
This map shows the width of the marsh at Parkgate to be 2 km, while the total width of the estuary at this point is 6 km. From Parkgate the channel of the river is barely visible, but the view from the A55 in Flintshire confirms that at this point the marsh extends for only about a third of the total width of the estuary.
The River Dee was canalised in the 18th century between Chester and Connah’s Quay in order to restore a channel for shipping to the ancient port of Chester; the work was completed in 1737.
The building of this channel directed the flow of the river over to the Welsh side of the estuary, and the subsequent lack of flow on the Cheshire side accelerated the silting there, eventually bringing to an end the shipping at Parkgate. By 1810 the Dublin Packet service had transferred to Liverpool. The continued silting later led to the creation of the marsh.
The point where the ‘new’ Dee channel from Chester discharges into the estuary is also identified on the map.