Rainfall Intensity for Sewer Design - Stage 2

Reference: 17/CL/10/17
ISBN: 1 84057 842 4
Published Date: 13/09/2017

This research and its data products make use of a new Met Office 1.5km climate length model simulation of the United Kingdom. This is important because the model can resolve convective processes that produce the heavy rain seen in all seasons which affects the functioning of urban drainage systems. The data products are optimised for use in the planning of urban drainage networks and the analysis of surface water flooding.

The two data products, aimed at urban drainage and storm water management professionals are: 

1.            Estimated changes in design storm uplifts, covering three different regions of the UK.

2.            A time series perturbation tool that allows rainfall time series to be adjusted to reflect estimated future rainfall conditions.

Estimated changes to design storms show similar or higher changes to those currently used by the water industry - this could have significant impacts on the resilience of sewer networks in the future, triggering different adaptive responses to protect customers and communities from flooding. The time series tool allows analysis of future changes to the operation of combined sewer overflows (CSOs) and wet weather loadings on treatment plants. 

Note: The software tool for this project can be downloaded from the 'Supporting Documents' CD.

Price: £250  

Rainfall Intensity for Sewer Design - Technical Guide

Reference: 15/CL/10/16-1
ISBN: 184057 771 1
Published Date: 06/07/2015

UK water and sewerage companies do not have a way of assessing the growing risk of customer flooding and pollution from CSOs. Previous research for UKWIR used UKCIP02 and UKCP09 projections and data. However, short-period rainfall statistics used to assess existing and new sewer systems are largely the result of convective rainfall.  Convective rainfall processes are not well simulated by Regional Climate Models (used in UKCP09 and predecessor projections).
Addressing this issue, this project has produced estimates of rainfall intensity change over different parts of the UK using a combination of climate analogue data and a high-resolution (1.5km) climate model developed by the UK Met Office both approaches capturing or resolving convective rainfall events. The resultant rainfall intensity change estimates are, in general, higher than existing UK guidance suggests.

Sewer flooding frequency and volume, and frequency of pollution events are also investigated for five locations; indicating that these are also likely to increase in the future. It is recommended that further work is undertaken to add confidence to the results produced and to inform future UK guidance.

Price: £50  

Climate Change Modelling for Sewerage Networks

Reference: 10/CL/10/15
ISBN: 1 84057 573 5
Published Date: 04/05/2011

The study provides guidance on incorporating climate change impacts into the modelling of sewerage networks. It is aimed at UK sewerage undertakers and their modelling consultants and is relevant for performance assessments and design.
The report acts as a stand-alone guide for which no detailed knowledge of climate change science is required. It provides a toolkit of approaches based on the use of the UK Climate Projections 2009 (UKCP09) weather generator, guiding the user through its application for including the impact of climate change on extreme rainfall for design storms and timeseries modelling. Twelve example case studies are presented from across the United Kingdom demonstrating the application of the methodology.
Software accompanying the report is provided to facilitate the selection and extraction by the user of data from the UKCP09 Weather Generator.

Price: £11