coastal erosion line kirk michael

Summary

The requester sought criteria, affected property lists, and reports regarding the coastal erosion line in Kirk Michael. The Department of Infrastructure disclosed that the methodology follows the UK NCERM2 approach and directed the requester to publicly available HaskoningDHV reports, while clarifying that no definitive list of affected residential addresses is held.

Key Facts

• The coastal erosion line is interpreted as the trigger for intervention outlined in the Kirk Michael coastal erosion strategic risk assessment.
• The methodology used follows the UK Environment Agency National Coastal Erosion Risk Mapping 2 (NCERM2) approach.
• No numerical modelling was undertaken for this study; assumptions are stated in the public strategic risk assessment.
• The Department of Infrastructure does not hold a definitive list of addresses for properties impacted by the erosion line.
• Impacted properties are visually highlighted in Figure 5.4 and Figure 5.1 of the Stage 1 Strategic Risk Assessment report.

Data Disclosed

• 2025-12-02
• 2025-12-23
• 5139649
• 5093521
• Figure 5.4
• Figure 5.1
• Page 27
• Table 3-1
• Table 3-2
• Section 4
• Section 3
• SC120017_TR_Shore_and_cliff_sensitivity_to_accelerating_sea_level_rise

Original Request

Department of Infrastructure Head Office Sea Terminal Douglas Isle of Man IM1 2RF E-mail: Enquiries@Highways.gov.im 02/12/25 Freedom of Information Request - Coastal Erosion Line, Kirk Michael Dear Sir/Madam, I am submitting this request under the Isle of Man Freedom of Information Act 2015. Further to the Cabinet Office response (Ref: 5093521, dated 01 December 2025), I am now directing my request to the Department of Infrastructure, as advised. I seek the following information relating to the designation of the coastal erosion line in Kirk Michael: 1. **Criteria and Methodology** A copy of the criteria, methodology, or technical guidance used to determine the coastal erosion line in Kirk Michael, including any modelling techniques, data sources, or assumptions applied. 2. **Residential Properties Affected** A list of all residential properties identified as being impacted by the coastal erosion line, including the number of houses affected. 3. **Supporting Reports or Assessments** Any reports, studies, or assessments held by the Department of Infrastructure that informed the designation of the coastal erosion line, beyond those already published on the Isle of Man Flood Hub. For ease of reference, please note this request follows on from Cabinet Office FOI Ref: 5093521. I look forward to your response within the statutory timeframe. Please confirm receipt of this request. Yours faithfully,

Data Tables (1)

Full Response Text

Department of Infrastructure Sea Terminal Building, Douglas, Isle of Man, IM1 2RF

Contact: FOI Response Team Telephone: (01624) 686785 Email: dpo-doi@gov.im

Our ref: 5139649 23 December 2025

Dear ###

We write further to your request, received 2 December 2025, which states:

Freedom of Information Request - Coastal Erosion Line, Kirk Michael

Dear Sir/Madam,

I am submitting this request under the Isle of Man Freedom of Information Act 2015.

Further to the Cabinet Office response (Ref: 5093521, dated 01 December 2025), I am now directing my request to the Department of Infrastructure, as advised. I seek the following information relating to the designation of the coastal erosion line in Kirk Michael:

1. Criteria and Methodology

A copy of the criteria, methodology, or technical guidance used to determine the coastal erosion line in Kirk Michael, including any modelling techniques, data sources, or assumptions applied.

1. Residential Properties Affected

A list of all residential properties identified as being impacted by the coastal erosion line, including the number of houses affected.

1. Supporting Reports or Assessments

Any reports, studies, or assessments held by the Department of Infrastructure that informed the designation of the coastal erosion line, beyond those already published on the Isle of Man Flood Hub.

For ease of reference, please note this request follows on from Cabinet Office FOI Ref: 5093521.

I look forward to your response within the statutory timeframe. Please confirm receipt of this request.

Yours faithfully,"

Our response to your request is as follows: I have detailed below the information that is being released to you.

I seek the following information relating to the designation of the coastal erosion line in Kirk Michael:

For the avoidance of doubt the ‘coastal erosion line’ has been interpreted as the trigger for intervention outlined in the Kirk Michael coastal erosion strategic risk assessment, specifically highlighted by figure 5.4 of the stage 1 report.

1. Criteria and Methodology A copy of the criteria, methodology, or technical guidance used to determine the coastal erosion line in Kirk Michael, including any modelling techniques, data sources, or assumptions applied.

The methodology used to determine the future predicted erosion contours highlighted in the HaskoningDHV Report (available publicly here: stage-1-strategic-risk- assessment-c01-redacted.pdf) are clearly set out in the report, particularly section 4 – Present Day and Future Erosion Rates. This highlights the methodology, following the UK Environment Agency National Coastal Erosion Risk Mapping 2 (NCERM2) approach. The guidance is available publicly here: SC120017_TR_Shore_and_cliff_sensitivity_to_accelerating_sea_level_rise No numerical modelling has been undertaken for this study and all assumptions are stated within the strategic risk assessment and economic appraisal report already available to the public. To determine the future position of the coast, the following historic data sources were used, as outlined the HaskoningDHV Report. Section 3 Historical Erosion, table 3-1 as highlighted below:

1. Residential Properties Affected A list of all residential properties identified as being impacted by the coastal erosion line, including the number of houses affected.

The department does not hold a definitive list of addresses associated with properties that may be impacted. Properties affected before and after the coastline reaches the trigger for intervention line is reached are highlighted on figure 5.4 of the stage-1- strategic-risk-assessment-c01-redacted.pdf. Individual properties that are predicted as being impacted before the trigger for intervention is reached are set out in figure 5.1, page 27 of the above linked report.
Table 3-2 (page 1)The economic appraisal (available publicly here: economic- assessment-report-c01-redacted.pdf) carried out as part of the strategic risk assessment indicates that in the worst case scenario, there are 81 residential and 5 non-residential properties at risk over the next 100 years, with a best estimate of 69 residential and 3 commercial properties.

1. Supporting Reports or Assessments Any reports, studies, or assessments held by the Department of Infrastructure that informed the designation of the coastal erosion line, beyond those already published on the Isle of Man Flood Hub.

All reports, studies or assessments held by the department & used to inform the future coast position are available publicly at: IOMFloodhub - Kirk Michael Please note, reports available at the above link between January 2024 and April 2025 have not formed part of the erosion risk assessment undertaken in 2023.
A complete list of references used to inform the risk assessment process can be found at the end of the HaskoningDHV report: stage-1-strategic-risk-assessment-c01- redacted.pdf

Please quote the reference number 5139649 in any future communications.

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I will now close your request as of this date.