Murray Dale speaks on future rainfall at the CIWEM Urban Drainage conference

Murray Dale, Hydrometeorology Technical Director, is presenting at the Urban Drainage Group Autumn Conference and Exhibition on 9 November. His talk, titled ‘Are you prepared for future rainfall?’, will cover the findings of a UK Water Industry Research (UKWIR) project on climate change impacts on rainfall intensity.

The conference is aimed at presenting, exchanging and discussing the latest knowledge and research from within the Urban Drainage industry both globally and locally. It attracts expert knowledge and leading representatives in the urban drainage field, encompassing a wide range of associated organisations and individuals.

The abstract of Murray’s presentation and paper, which was written with inputs from Elliot Gill and Bob Potter from CH2M, is below.

Are you prepared for future rainfall? Results from the UKWIR rainfall intensity project

Climate is changing and rainfall is changing, but by how much? The answer to this question has been a concern for the water industry for two decades. UKWIR has looked at this issue from 2001, commissioning a series of research projects. In 2014 UKWIR stated that “Water and sewerage companies (WaSCs) do not have a way of assessing the growing risk of customer flooding based on the climate science.” Key to the problem was the spatial resolution of climate models – they were too course to resolve convective processes that lead to the highest rainfall intensities.

Addressing this concern, UKWIR commissioned a study led by CH2M to improve their understanding of rainfall intensity changes and how these affect sewerage systems. Drawing on research expertise and the latest climate modelling science at the Met Office Hadley Centre and Newcastle University, a team at CH2M led by Murray Dale (who now works for us) has produced:

  • New design storm uplift estimates for the UK on a regional basis
  • A time series perturbation tool to allow historic rainfall time series data to be adjusted to reflect future rainfall conditions

Murray’s paper explains the methods used to produce these outputs and highlights the impacts of the change estimates on flooding, CSO spill volumes and frequencies. Broadly, findings show that design storm uplifts are similar to the guidance by Defra and the Environment Agency for southern parts of the UK, but higher than the guidance in the northern parts of the UK. Time series analysis indicates a mixed picture – some decreases in spill frequencies and volumes and some increases, depending on UK location.

The paper and presentation will be of interest to all urban drainage planners and modellers looking to improve their understanding of future risks and outcomes. Improving how we respond to this uncertainty is central to delivering effective 21st Century drainage.

Adam Dean Award

The Adam Dean Award winner is also due to be announced on the last day of the conference. Last year Rosie Hampson and Stuart Marshfield, Assistant Analyst’s, were shortlisted as two of the six finalists. Visit our Knowledge Hub to find out more.

Want to know more?

Contact Murray Dale for more information on this project. You can also visit our Flood Risk Assessment web page for more information on urban drainage and our work in this area.

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