Policy ARL10: Flood Risk Management

The Policy

Development proposals will be expected to:

  • be designed and constructed to reduce the overall level of flood risk within the parish; and
  • provide appropriate surface water drainage including permeable driveways and parking areas, water harvesting and storage features, green roofs and/or soakaways; and
  • provide open existing culverts where practicable.

Development will not be permitted in flood attenuation areas where that development would reduce the ability of these areas to alleviate flooding.

Proposals will need to demonstrate that development has avoided the loss of open water courses through culverting with existing culverted sections opened up where viable.

Any new development must have adequate receiving surface water drainage, i.e. drains, culverts and definable water courses, under Environment Agency and Local Authority control.

Development proposals will be expected to:

  • be designed and constructed to reduce the overall level of flood risk within the parish; and
  • provide appropriate surface water drainage including permeable driveways and parking areas, water harvesting and storage features, green roofs and/or soakaways; and

  • provide open existing culverts where practicable.

Any new development must ensure that appropriate measures are secured to ensure the adoption and ongoing maintenance of any flood prevention measures.

The Background

A number of areas within the parish have been affected by flooding over the past decades for a variety of reasons:

  • Limited capacity (and historically poor maintenance) at the River Hiz and Pix Brook: The car park (west of the station) had only just been completed, in February 2014, to a “1 in a 100 years” flooding specification, and within a few weeks it was flooded (albeit for just a day). The Pix has historically caused flooding to residents of Stotfold Road, although better maintenance (as a result of pressure from residents) has reduced the problem.
    Flooding in 2014

    Flooding in 2014

  • Naturally high water table: The 1993 flooding was due to saturated ground, with nowhere for the water to go. Similar problems have occurred at the football grounds. And a few years ago an expensive drainage scheme had to be installed at the cemetery as graves could not be dug due to high ground water.

  • Natural Springs: There are believed to be several underground springs just below the surface in some areas. When the Chancellors estate was being built (about 10 years ago), construction work was held up because they had opened up a spring when constructing foundations.
  • Limited drainage channels from the east side of the railway to the River Hiz on the West: The railway creates a barrier for water draining down from the higher ground to the east, and the limited number of drainage channels under the railway are considered to be not really adequate.
    Flooding on Old Oak Close

    Flooding on Old Oak Close

The CBC Local Flood Risk Management Strategy identifies that flooding is likely to be increasingly an issue for the area partly as a result of climate change: warmer wetter winters, hotter, drier summers, fewer days of ice, frost and snow, and a higher likelihood of extreme weather events including heatwaves and intense rainfall.

The Strategy notes that Arlesey is one of the areas more susceptible to local flooding and commits to preparing a Surface Water Management Plan. Objective 6 of the Strategy encourages local communities to become involved in reducing flood risk by providing training and support to set up community response groups and take responsibility for monitoring flooding within communities. The neighbourhood plan engagement revealed that local people are concerned about pollution – water, air, light and noise – and that they would be keen to monitor it. There is scope therefore to extend the monitoring of flooding to these other aspects.

To ensure that flooding and drainage matters are not made worse in the future, it is essential that any new development fully takes into account its possible impact on flooding and drainage issues not only within the site itself but its off-site effects within the town and surrounding areas. Development schemes will need to ensure that they provide proposals and supporting evidence to ensure that any drainage from the site and proposed development, will not increase the flood risk of properties in the town and surrounding areas and in accordance with national and Core Strategy policies, should aim to integrate measures to reduce flood risk. In particular, the creation of new culverts will not be viewed favourably as it is consistently observed that developments which do so, serve to increase the prospects of localised flooding.

Non-policy action

The community will work with CBC, Environment Agency and other partners to put in place a mechanism for monitoring and recording flooding as well as other environmental impacts associated with development such as noise. light and air pollution.