Flood Risk Assessments

Landowners and developers have a primary responsibility for safeguarding their land and other property against natural hazards such as flooding.  Depending on the size and location of a development it is likely that a Flood Risk/Consequence Assessment Report will need to be submitted and approved in order to secure Planning Permission.

Firstly to clarify, a Flood Consequence Assessment (FCA) is undertaken in Wales and satisfies the requirements of TAN15.  A Flood Risk Assessment (FRA) is undertaken in England and fits the National Planning Policy Framework Structure (NPPF).

The complexity and technical content of these reports vary considerably depending on the Flood Zone they are located within and the type of development being considered. All these reports deal with any potential fluvial flood risks to the site and surface water flood risks to both the on site users as well as those downstream of the site. Our strategy for delivering approved FRA/FCA reports is usually a 2 stage approach involving the following:

Flood Risk Screening (Stage 1)

Our Flood Risk Screening work establishes the extent of the work necessary to satisfy the Environment Agency (EA)/Natural Resources Wales (NRW) and the Local Planning Authority’s (LPA) requirements and involves the following:

  • Contacting and liaising with the EA/NRW to obtain any Flood Risk information it has for the site and immediate vicinity and establish its specific Flood Risk Management requirements.
  • Establishing (in consultation with the LPA and the EA/NRW) the design lifetime of the proposed development and the proposed standards for flood defence and safety.
  • Researching publicly available relevant documents such as Catchment Flood Management Plans, Regional Flood Risk Appraisal, Preliminary Flood Risk Assessments, etc.
  • Contact the local Water Authority to obtain information on the capacity of their existing sewer network in the vicinity of the site, as well as identifying any known problems they may have with their network.
  • Establish current local planning authority policies in relation to flood protection, surface water drainage, sustainable drainage and protection/recharge of groundwater (including any strategic flood risk assessments [SFRAs] or precursor documentation which may have been prepared).
  • Examine documentary geological and borehole records for groundwater depths and quality data.
  • Establish which are the sources as well as the potential sources of flood risk.
  •  Having undertaken the above work we will have defined the required scope of works to be covered within the FCA/FRA Report to be submitted in support of the Planning Application.

Flood Risk/Consequence Assessment Reports (Stage 2)

Our FCA/FRA reports deliver a safe development adopting environmentally sustainable and affordable solutions designed to mitigate any flood risks resulting from the proposed development. The key issues addressed within this report include a detailed assessment of the following on-and off-site:

  • Hydrological systems
  • Surface water drainage systems
  • Foul water drainage systems (to the extent that they are affected by surface water systems or flood risk)
  • Sources of flood risk
  • Exposure to flood risk
  • Consequences of flooding, and
  • Groundwater resources
  • Key Risks and potential impacts being evaluated within the report include:
  • Proposed Standards for flood defence:
  • Flood Risk to the Site (sources and consequences):
  • Flood Risk from the Site (sources and consequences):
  • Climate Change effects
  • Groundwater resources
  • Residual Risks
  • The existing (baseline) conditions
  • The proposed (design) conditions at the end of the design lifetime of the development
  • The proposed means of mitigation
  • The conditions during construction
  • The “do nothing” scenario.

The Results and Conclusions delivered in our reports:

  • Confirm that the proposed development is unlikely to be affected by flooding from any source,
  • Prove the development will not increase the flood risk elsewhere
  • Provide details of the measures proposed to deal with the effects and risks;
  • Satisfy the EA/NRW and LPA that any flood risk arising from the proposals will be successfully managed with minimal adverse environment effect.
  • Incorporate sustainable drainage systems and, where necessary, flood resilience measures
  • Identify opportunities to reduce flood risk, enhance biodiversity and amenity and seek collective solutions to managing flood risk.
  • Protect the proposed development from unacceptable flooding or flood hazards
  • Protect offsite land and property from increased flood risk or flood hazard due to the development proposals
  • Ensure that the surface water discharging from drains within the development are contained within the development
  • Maintaining surface water discharges from the site at present (or reduced) levels, including accommodation of the increased run-off anticipated due to climate change during the lifetime of the development.

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