Stop 11: The River Lavant-Information
This a good place to stand to get an idea about the river Lavant.
Where you are standing is probably currently a dry ford across Woodberry Lane. If so, when you are facing towards Rowlands Castle, you will see a meadow to your right and a pole measuring potential depth of water, to your left as in the photograph above.
Come here during a wet winter and you will be met with a very different scene as the river Lavant may be flowing freely across the road with the meadow to your right now being underwater and the pole to your right, showing the depth of the stream. It is often then impassable to vehicles and the road will have been closed to motor vehicles. Deep water tends to be seen as a challenge to some motorists and Hall’s Garage has been involved in rescuing many cars over the years!
In the 1950s, locals have said that the Lavant flowed every winter but over the past twenty years, it has flowed about once every three years.
The river Lavant emerges from springs in the ground North of Finchdean and tracks down through Rowlands Castle and then onto Havant. Despite its name, it is not related to the river Lavant that flows through Chichester. I understand from a geologist that our river is sometimes referred to as the “West Lavant” to distinguish it from the East Lavant that flows through Chichester. The word “Lavant” possibly comes from a Middle English word “lavand” which meant to stream, pour out or wash. Our river is a winterbourne stream that erupts from springs when the water in the water table of the chalk aquifer rises.
Beneath you is sedimentary rock, consisting of limestone, also known as chalk, which formed during the Cretaceous Period from 145-66 million years ago when this land was underwater. During the Cretaceous Period, Earth was warmer than it is today. The world was ice free, and forests stretched to the Poles. Incidentally, clay is a common component of sedimentary rock like chalk, and generations of inhabitants in this locality, going back to the Romans have used that clay in the making of bricks.
Chalk deposits are generally very permeable and act as aquifers, which means they hold groundwater and the amount held depends partly on the rainfall, so the height of the water table in chalk aquifers tends to rise in winter and fall in summer. This rise and fall of the water table, partly accounts for the characteristics features of chalk or Karst landscapes, such as dry valleys or coombes, and seasonally-flowing streams arising from springs, where water can appear from the ground but also sinkholes, where the water can disappear into the ground. A sink hole once suddenly appeared on Rowlands Castle Golf Course and reportedly swallowed a tree.