Holders Hill

FRA-HH (16-9)

JNP Group formed part of the planning team for this residential redevelopment in north-west London, providing advice on flood risk issues on development proposals and preparing a Flood Risk Assessment to support the successful planning application.

The site contained an existing residential property with hard-standing drive/patio areas and a soft landscaped rear garden with levels falling away from the property towards Dollis Brook, a tributary of the River Brent.

An initial review of the Environment Agency ‘s (EA) flood maps revealed large areas of the site to be located within Flood Zones 2 and 3, thus requiring a Flood Risk Assessment to support the planning application.

Flood Risk Data

JNP Group accurately established the extents of the floodplain by obtaining the EA modelled flood levels and plotting against site topographic survey information.

These works enabled JNP Group to provide a Flood Risk Assessment which satisfactorily demonstrated that the site could be developed with no increased risk of flooding on or off-site.

JNP Group services provided:

  • Advice on the implications of national guidance (PPS25) on the planning application.
  • Guidance on site layout and levels with relation to flood extents.
  • Designed a flood compensation scheme which set levels around the proposed layout and mitigated for an increased building footprint within the floodplain.
  • Undertook a preliminary assessment of surface water drainage and set criteria for management of surface water runoff from the development.
  • Demonstrated safe means of escape from the development during flood events.
  • Undertook discussions with the EA to secure pre-planning approval of the above.
  • Flood Risk Assessment.
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