Slipper Mill Pond Preservation Association
Registered Charity No:277744

The River Ems

Slipper Mill Pond forms part of the estuary of the River Ems into the sea in Chichester Harbour.

The River Ems has a catchment area of some 55 square kilometres, and its upper reaches drain the South Downs. Flows in the river are typical of chalk upland streams or "Bournes".  There is little or no surface water  in prolonged dry periods as the downstream springs have lowered the level of the water-table.    However when the underlying aquifers are full the rain runs off and the stream system starts to function.  

Under extreme conditions flows of as much as 6 cubic metres per second have been noted at the Environment Agency gauging station at Westbourne.

It has been estimated that the Ems  carries a suspended load input of 1,450 tonnes/km²/yr and bedload of between 268 and 541 tonnes/yr (estimated by Rendel Geotechnics and the University of Portsmouth (1996). For more information  visit the SCOPAC Web site)

The Emsworth Stream system has been used since mediaeval times to power water mills in its lower reaches, and the complex channel system is testament to this. Features affecting the flow regime into the pond include how the sluice gates are set at Constant Springs just below Lumley Mill, and the flow controls at the Queen Street. The maintenance and settings of the structures and  sluices are the responsibility of the individual owners of the land.

Extreme high tides overwhelm the pond banks and can cause flooding - see the "Flooding" Screen.

Sea wall submerged - March 2001

The River Notes screen contains a description of the features of the lower reaches of the river affecting the pond.

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