Infrastructure - Water Management & Flooding
The Association is very concerned about the level of water in the pond from many points of view – it must be kept full for as much of the time as possible to preserve its ecosystem.
To be able to state that flooding is independent of the management of the pond gates and sluice can only be made after much research and considering all the evidence. Both flooding from the The River Ems and the tidal flooding have been examined in detail.
If you are worried / affected by flooding, useful resources can be found on the Blue Pages website.
"Any flooding around the pond is purely due to the tide".
1. Environment Agency
Their 'flooding risk' map of the area shows that the land flanking the river and the pond is classified as being in the tidal risk area. Advice on responsibilities, mills and weirs and flooding is fully covered on their website.
2. Local Construction Limit
"Safe" building levels depend on location. Havant Borough Council or Chichester District Council should be consulted for more information. Details including wave heights are available from many sources including the East Solent Coastline Management Plan. The Environment Agency's “Portchester Castle to Emsworth Coastal Study" is also worth consulting.
3. Burgess Report
The SMPPA commissioned John Burgess, a Hydraulic Engineer, to investigate the problems experienced in the Spring of 2001 when there was flooding due both to high tides and the river in spate. His investigations revealed that the flooding experienced at the Lumley Cottages was due to the volume of water flowing in the stream in front of them, and was independent of the Pond management regime.
4. Lower River Ems Management Group
Matters came to a head with the exceptional rainfall event of June 2012 when Lumley Cottages were flooded.
Discussions with the authorities supported the SMPPA's assertion that the pond had no effect on upstream flooding so to help resolve the issues the LERMG came into being in February 2014.
This exceptionally friendly group consists of:
• Environment Agency
• West Sussex County Council
• Havant Borough Council
• Constant Spring
• Lumley Cottages residents
• Brook Meadow Conservation Group
• Gooseberry Cottage
• Lower Lumley Road residents
They meet regularly and have succeeded in:
• EA taking over and replacing the sluice at Constant Spring
• Lumley Cottage protection being installed thanks to grants
• Operation of the Balancing Pond of South Brook Meadow
• Lower Lumley Road pond bank improvements funded by a WSCC Waterside Grant
• Upgrading the of balancing pond bank and increasing the capacity of the non-return valve at the exit
The EA have undertaken an Initial Assessment of the Lower Ems from Westbourne to the sea which should lead to further improvements.
5. Sediment Management Upstream - A useful summary can be found here
green - tidal risk zone
blue - river flooding risk
Issued by the Environment Agency
Photo thanks to John Brown
Lumley Cottages - Flood wall (LERMG)
Constant Spring - new Sluice
Balancing Pond - Outlet Structure
All pictures below were taken at the exceptional high tide at the time of the investigation in March 2001 by SMPPA.
South Sea Wall
West sea wall submerged
Brook Meadow upper field looking towards Lumley Road- note standing Water
Gooseberry Footpath Bridge