Neither Tidal nor Surface Water Flood Risk a Constraint on Development, where Castle Point Council are concerned!

The issue of potential Flooding remains a Hot Topic. That is as it should be, however as we have seen within Castle Point Council it only acts as a Development Constraint verbally, rather than effectively.

The responsibility on Flood Risk should fall squarely on the shoulders of council members, but other interests and “fear” of scaremongering, in effect mean that Flood Risk as a Constraint on Development is disregarded.

Floods 2014 pic via Police Helicopter

View of Canvey Island flooding from Police Helicopter July 2014

The Environment Agency adopt a position where residents safety over the lifetime of a new development is left to council members, Canvey Island and mainland residents Representatives.

The EA consider;

“The site is currently protected by flood defences so is not at risk of flooding in the present-day 0.0% (1 in 1000) annual probability flood event. The defences will continue to offer protection over the lifetime of the development, provided that the TE2100 policy is followed and the defences are raised in line with climate change, which is dependent on future funding.” 

The Island’s Flood Risk Assessment confirms over topping will be a concern prior to the year 2100!

There are no guarantees of this future funding and residents may be surprised to know that much of this funding must be raised locally. Councillors should be in a position to inform us of the sources of this funding and of the avenues in place for the collection of these monies, if they are confident that the sea defences will receive the necessary improvements so as to have confidence any new builds that they approve, will be safe over its Lifetime!

The EA give further warning;

“Although Canvey Island is defended to a high standard of protection, it is at risk should there be a flood defence failure” 

Of course the official position of cpbc appears to be that as long as there is space provided for safe refuge areas above the ground floor, development is acceptable.

A somewhat contradictory position in respect that if Canvey Island could not Flood, the safe refuge requirement would be un-necessary.

Government and Defra continue to fumble about giving residents no security whilst planners and developers take advantage of the lack of a clear position.

The BBC Report;

The Commons environment committee said ministers were not addressing what it called the fragmented, inefficient and ineffective flood management.

Areas of concern include flood impact home insurance, building rules and local authority planning decisions.

The government rejected the criticism, saying it had accepted many previous suggestions on flooding from the MPs.

The committee’s comments are the latest in a running tussle between MPs and the environment department Defra.

 The MPs admit that flooding has risen up the government’s priority list, and say “considerable work” on flooding is being done across Whitehall. But they complain that ministers are still ignoring reasonable demands.

Jim Fitzpatrick MP, acting chair of the Environment, Food and Rural Affairs Committee (Efra), said: “People living in areas of flood risk need to be reassured that the government is acting to improve our disjointed flood management system.

“Defra has failed to give sufficient justification for its rejection of our recommendations for important new measures.”

Continued development also increases pressure on Canvey Island’s drainage system, already capable of failure through misuse and lack of maintenance. Housing and Business development means Roads, Parking areas and hard impermeable surfaces intensify this issue as development approvals continue unabated.

This move to develop more and more areas of grass land on Canvey must be considered in the light of it inevitably increasing the likelihood of Surface Water Flooding, a warning of this issue is contained in a Research paper by Dr David Kelly. Its relevance to Canvey Island should be considered Striking!

It should be remembered that, whilst the sea defences have some ability to stop the Tide from over topping, they have absolutely no effect in stopping the Tidal Water from penetrating the ground from beneath, and causing flooding and a High Water Table by that means!

Impact of paved front gardens on current and future urban flooding” Research Paper by Dr D.A.Kelly

The proliferation of paved gardens is putting the UK’s towns and cities at greater risk of flooding and, by 2080, the UK’s urban drainage system could be overwhelmed by ‘runoff’ equivalent to the volume of up to 100 Olympic-sized swimming pools.  

The potential impact that paved gardens could have on urban flooding in Edinburgh, Exeter, Manchester and London by 2050 and 2080 was examined by Dr David Kelly, associate professor in Heriot-Watt’s Water Academy. 

Many gardens in the UK have been paved by homeowners who want low maintenance gardens or off-street parking. Covering traditional gardens with hard paving, and the subsequent loss of green vegetation, reduces the amount of rainfall that can be dealt with naturally and significantly increases the rate and volume of runoff flowing to surface water drainage systems. 

Dr Kelly applied projected rainfall intensities for each of the four UK cities to simulated front gardens that reflect the trends for paving. 

Calculating the runoff contribution from new and existing paved gardens will help planners and policy makers identify areas of risk in their town and city – and decide whether to call for homeowners to depave. Additionally, data of runoff from individual paved gardens could highlight the need for behaviour change, and help encourage homeowners to take action themselves by depaving their gardens and enhancing green vegetation.

Dr Kelly, assistant professor in Heriot-Watt University’s Water Institute said: “Domestic front gardens cover almost 30% of our urban space and play a vital role in managing surface water runoff in towns and cities. 

“Existing urban drainage systems will be inadequate to cope with the level of increased runoff from paved front gardens. With runoff from all impermeable surfaces, including paved front gardens, likely to increase in future due to urban densification, the risk of urban flooding will increase unless substantial efforts are made to minimise runoff.”

Homeowners and policymakers need to focus on depaving gardens across the UK.

Dr Kelly’s research showed that the collective runoff by the 2080s from front gardens alone is expected to increase by substantial amounts during extreme storm events due to climate change. 

“In Edinburgh, considering only gardens that are currently at least three-quarters paved, during just one storm, runoff could increase to 29,000m3 across the city, equivalent to 12 Olympic swimming pools, by 2080.”  

“In London, the volume of runoff could increase up to as much as 278,000m3 (equivalent to 100 Olympic swimming pools). ” 

“But, if all of these gardens were depaved and had zero impermeable cover, then the runoff could almost be eliminated, particularly if combined with enhanced green vegetation solutions.”

 D.A.Kelly’s research paper; “Impact of paved front gardens on current and future urban flooding” can be found HERE

The full BBC Environment Parliamentary Report can be found HERE.

 

 

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2 responses to “Neither Tidal nor Surface Water Flood Risk a Constraint on Development, where Castle Point Council are concerned!

  1. Editor
    I am sure that CPBC Planning Committee take the following recommendations into consideration when dealing with developments on Canvey Island.

    New developments are required to provide safe access and exit during a flood and the measures by which this will be achieved should be clear in the Flood Risk Assessment (FRA). Safe access and exit is required to enable the evacuation of people from the development, provide the emergency services with access to the development during a flood and enable flood defence authorities to carry out any necessary duties during the period of flood.

    A safe access or exit route is a route that is safe for use by occupiers without the intervention of the emergency services or others.
    Safe routes should be identified both inside and beyond the boundary of the new development. Even where a new development is above the floodplain and considered acceptable with regard to its impact on flood flows and flood storage, it should be demonstrated that the routes to and from the development are also safe to use.

    A route can only be completely safe in flood risk terms if it is dry at all times.

    Requirements for Safe Access and Exit

    The requirements for safe access and exit from new developments in flood risk areas are as follows, in decreasing order of preference:

    .Safe dry route for people and vehicles.
    .Safe dry route for people.
    .If a dry route for people is not possible, a route for people where the flood hazard (in terms of depth and velocity of flooding) is low and should not cause a risk to people.
    .If a dry route for vehicles is not possible, a route for vehicles where the flood hazard (in terms of depth and velocity of flooding) is low to permit access for emergency vehicles. However the public should not drive vehicles in floodwater.
    .Where a dry route is not possible and a route with low flood hazard is identified, the route should not have any service covers that could be removed, or other underwater hazards.
    .It is often difficult to see underwater hazards even in shallow water, particularly at night or if the water is silty. In addition, the route should be clearly marked, for example using painted posts.

  2. Editor.
    We are consistently informed that Emergency Planning is not a consideration for planning issues. However very recently The Essex County Council,” Flood and Water Management Planning and Environment” team reminded CPBC Planning Officers of the following :-

    Flood Risk responsibilities for your Council
    The following paragraphs provide guidance to assist you in determining matters which are your responsibility to consider.

    • Safety of People (including the provision and adequacy of an emergency plan, temporary refuge and rescue or evacuation arrangements)

    You need to be satisfied that the proposed procedures will ensure the safety of future occupants of the development. In all circumstances where warning and emergency response is fundamental to managing flood risk, we advise LPAs formally consider the emergency planning and rescue implications of new development in making their decisions. We do not normally comment on or approve the adequacy of flood emergency response procedures accompanying development proposals as we do not carry out these roles during a flood.

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