Strategic Flood Risk Assessment for the Draft Cork City Development Plan 2022-2028
2.3 Other Flood Studies Other Flood Studies considered in the preparation of this assessment include:
Flood Risk Management Plan (Lee, Cork Harbour and Youghal Bay River Basin), 2018; Websites and documentation for the following measures under the Flood Risk Management Plan including: o Lower Lee Flood Relief Scheme o Douglas Flood Relief Scheme o Glashaboy Flood Relief Scheme Previous relevant SFRAs in Cork City and County Regional Flood Risk Assessment for the Southern Regional Spatial and Economic Strategy. 2.4 Flood Risk Indicators Indicators of flood risk that are based on historical flooding events are identified and described on able 2 and mapped in Appendix II . Indicators of flood risk that are based on computational models – predictive flood risk indicators – are identified and described on Table 3 and mapped in Appendix II . able 2 Historical Flood Risk Indicators
Information Source
Description
Strategic Limitations
Recorded Flood Events from the OPW
This only provides a spot location dataset This only provides a spot location dataset
A flood event is the occurrence of recorded flooding at a given location on a given date. The flood event is derived from different types of information (reports, photographs etc.). A flood event that has occurred more than once at a certain area is named a recurring flood event. A flood extent is an inundated area as recorded at a certain moment in time. This layer of information includes floods recorded in 1999/2000 and 1954. Mineral alluvial soil mapping is indicative of recurrent or significant fluvial flooding at some point in the past and was generated by Teagasc with co-operation of the Forest Service, EPA and GSI. This project was completed May 2006. This drainage scheme mapping dataset was prepared on behalf of the Drainage Districts (Local Authorities with statutory responsibility for maintenance under the Arterial Drainage Act, 1925). These maps identify land that might benefit from the implementation of Arterial (Major) Drainage Schemes and indicate areas of land subject to flooding or poor drainage. This dataset indicates areas of land defended to some degree against flooding that were formerly the responsibility of the Land Commission.
Recurring Events
Flood
OPW Flood Extent
Coverage limited
Alluvium Soils
Drainage may have changed significantly since these soils were deposited. Identifies large broad areas - very low resolution for flood risk management
Drainage Districts (OPW)
Land (OPW)
Commission
Identifies broad areas - low resolution for flood risk management
Table 3 Predictive Flood Risk Indicators
Information Source
Description
Strategic Limitations
CFRAM Study, Flood Extent Mapping, 2016
Spatial spread is limited, including to the areas that are considered to be at most risk of flooding.
Following the undertaking of the PFRA, the OPW, through its engineering consultants and working with local authorities and other stakeholders, conducted extensive engineering assessments to better understand and detail the actual risk from flooding for areas that were at highest levels of risk. This was the subject of public consultation. The outcome of that work includes Predicted Flood Extent maps that were finalised in 2016. For fluvial flood levels, calibration and verification of the models make use of the best available data including hydrometric records, photographs, videos, press articles and anecdotal information. The OPW PFRA mapping dataset has been arrived at by: • Reviewing records of floods that have happened in the past; • Undertaking analysis to determine which areas might flood in the future, and what the impacts might be; and
OPW Flood
Preliminary
The PFRA is only a preliminary assessment, based on available or readily derivable information. Analysis has
Risk Assessment (PFRA) Fluvial, Groundwater and
CAAS for Cork City Council
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