ENVIRONMENT AGENCY DRAINAGE VIDEO – CANVEY ISLAND

Here is the official Environment Agency short webcast, highlighting the complexity and size of the drainage network serving Canvey Island.

All Canvey Islandresidents existing or future should watch this short webcast!

From the contents it is not difficult to imagine how easy the many linking connections fall foul to blockages and other repercussions backing up the network.

Clearly regular maintenance and general clearage work must be permanently ongoing.

Financial cut backs at any one of the Agencies with responsibility for the efficient working of this system, whether the Environment Agency, Essex Highways or Anglian Water has had, and will have the potential for disastrous effect!

Castle Point Council’s responsibilities will be considered once the long awaited Scrutiny Report on the Canvey Island Floods of July 2014.

 

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6 responses to “ENVIRONMENT AGENCY DRAINAGE VIDEO – CANVEY ISLAND

  1. Steve Sawkins

    Thanks once again Editor for keeping this issue alive whilst the Local Planning Authority deliberate upon large scale developments destined for Canvey Island.

    A further helpful reminder from ECC is the following report :-

    Essex County Council Flood Investigation Report
    Drainage on Canvey Island
    Canvey has been developed on an extremely flat and low lying estuarine island in the mouth of the River Thames with a land height of approximately 1m below the mean high water level, its current form being the result of nearly 500 years of land reclamation and drainage. The island has been historically susceptible to all sources of flooding, and is protected from tidal flooding by a sea wall on all sides. As a consequence the water level on the other side of the sea wall is regularly higher than the land, meaning that the drainage of surface water is wholly reliant on pumps to discharge water into the estuary at these times. These pumps are the final element of a long, incredibly complex and interlinked surface water drainage system, comprising of drains, culverts, sewers, open watercourses, main rivers, pumps and storage areas all with varying capacity, which need to be operating efficiently in order to drain the island. Rainfall on the island may flow a substantial distance before reaching the pumps, through infrastructure owned or managed by a large number of different organisations and individuals and in some cases without a clear understanding of ownership. Any constriction on flow either due to blockage or insufficient capacity for the rainfall event can affect the effective operation of the entire drainage system.
    The island has a history of surface water flooding, with several locations experiencing flooding issues on more than one occasion outside of the large magnitude events of 20th July 2014 and 24th August 2013. As a result of the relatively densely populated urban areas and large areas of impermeable surfaces the island is especially susceptible to intense rainfall events which result in flash flooding. In combination with the flat topography of the island this means that Canvey is particularly dependent on the designed drainage infrastructure to mitigate flood risk.

  2. Steve, we appreciate your input. Glad you are also abreast of the shortcomings of both the capacity limitations of the drainage system and the dubious history of planning locally that has added to the problems.
    The major issue hovering in the background is the intended use of constraints on development within the Flood Risk Zone that is Canvey Island. Local Planners have identified a risk at Canvey, calculated a corresponding number, and then applied this “ficticious” number across the whole Borough so as to lessen the housing need / supply requiring satisfying.
    Editor

  3. Steve Sawkins

    The planning inspector and developers are well aware that the term constraint is intrinsically link to foot note 9 of the NPPF. However should the Authority chose, as they have consistently done, to develop on Zone 3 flood plain then flood plain can no longer be offered as a constraint.
    Equally if the authority decides to develop within the hazard range of a COMAH site then obviously they will need to consider the ramifications of such a decision.
    Objectively Assessed Housing Needs have been clearly identified by the highly professional work undertaken by the authorities planning officers, which will be difficult to over come, should the authority try to make provisions for a lesser amount having previously allocated development on flood plain.

  4. Whilst I agree with your logic, Steve, regarding previous development in the Flood Risk Zone, Canvey Island, I would contend that two wrongs don’t make a right! Over development has been recognised as a reason for the flooding in 2014 by ECC. They indicated concern that more large development was planned by “our” local authority.
    The EA have at last exercised some concern by issuing Holding Objections on the large development proposed.
    Worryingly the issue of Constraints, especially Flood Risk AND Green Belt appears to have suddenly gone off Agenda now that the Election has been decided. It is interesting that politicians or representatives of all sides have gone strangely silent on the important issues that have been covered on this Blog of late.
    Not something that gives off confidence to the residents..
    Editor

  5. David Eastabrook

    I thought the video report of the Canvey Island drainage systems was very comprehensive and highlights the need to keep drainage systems free flowing at all times.

    I can report that in the past, I have personally cleared all the ditches and drainage headwalls that exist on the Canvey golf course. I did this to ensure the Waterside allotments didn’t flood. I have done this twice now because no-one clears the ditches at all. The ditches quickly block up with tree branches and all manner of debris like bales of free issue papers, fence posts and silt through the pipelines. I have numerous before and after photos of the ditches/ headwalls after being dug out.

    I reported the state of the ditches to the Parish Council and was told it was down to Essex County Council to deal with this matter. I was also told that the Golf Club was supposed to ensure the free flowing of water through the golf course and that this was part of their lease agreement.

    Over the last 8 years or so I have never seen anyone cleaning the ditches across the Golf Course and every two or three years the water fails to flow to the drainage open concrete channel which leads to the pumping station at Hilton.

    There is also visual evidence from Somnes Avenue of the drainage ditch which flows through the Waterside playing fields being constantly full of water, which would suggest that this ditch receives no attention to its drainage as well.

    • Thanks David, it will be interesting to see if the CPBC Scrutiny Report uncovers similar lack of maintenance.
      We await its publication.
      Editor

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