Flood forecasting for the River Ayr and Annick Water

Location: Ayrshire, Scotland                                                                                                                              Client: Scottish Environment Protection Agency (SEPA)

Challenge

We were tasked to develop a new flood forecasting model and warning thresholds for the River Ayr and Annick Water in Ayrshire, Scotland on behalf of SEPA. As part of this project, we needed to recalibrate SEPA’s existing forecast models for the River Irvine and provide revised flood mapping for the Upper Ayr using 1D/2D modelling.

Solution

The forecast system comprises:

  • Five gauged lumped Probability Distributed Models (PDMs) for rainfall runoff modelling
  • Six ungauged lumped PDMs and five 1D Flood Modeller (FM) Pro routing models
  • Three hydraulic models and eighteen forecast locations

The forecast locations are at key warning areas and at gauging stations, with error correction at the gauging stations.

Upper Ayr gauging station
Flow routing from Limmerhaugh gauging station to Catrine gauging station on the upper Ayr. Observed = dashed line. Simulated = solid line

We reviewed ratings and developed new ratings, including at the key gauging stations Dreghorn, Mainholm and Shewalton. We estimated flood warning thresholds, through the development of eight new FM hydraulic models.

We carried out end to end testing to ensure consistency of results between the models and the operational versions on SEPA’s national flood forecasting system FEWS. In addition, we undertook flood mapping of the upper Ayr using a linked 1D/2D Flood Modeller/TUFLOW model, to improve upon SEPA’s national flood risk map outputs.

Benefit

The new flood forecasting and warning system is now operational, and improved flood mapping is available.

Flood warnings can be viewed on the SEPA website here. To view the Ayr and Annick Water data expand the “Ayrshire and Arran” section.

Want to know more?

Email David Cameron for more information about this flood modelling project for the River Ayr and Annick Water in Ayrshire.  You can also find out more on our Flood Modelling webpages.



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