Critical duration event
The SuDS Manual published by CIRIA in 2015 defines a critical duration event as:
‘The duration of rainfall event likely to cause the highest peak flows or levels at a particular location, for a specified return period event.’
Where a rainfall event is: ‘A single occurrence of rainfall before and after which there is a dry period that is sufficient to allow its effect on the drainage system to be defined.’
And a return period is: ‘An estimate of the likelihood of a particular event occurring. A 100-year storm refers to the storm that occurs on average once every hundred years. In other words, its annual probability of exceedance is 1% (1:100).’
A design event is: 'A synthetic rainfall event of a given duration and return period that has been derived by statistical analysis.'
Rainfall intensity is the: ‘amount of rainfall occurring in a unit of time, expressed in mm/hr.’
[edit] Related articles on Designing Buildings Wiki
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
The adaptive reuse of large industrial structures.
Promoting the circular economy by extending the life of buildings.
CIAT responds to Climate Change Committee report
An urgent wake-up call for both government and the built environment.
Construction Management, 24 June
FMB pilot aims to build pipeline of site-ready tradespeople.
A quick introduction.
CLC publishes Mental Health Joint Code of Practice.
A quick introduction to its uses and risks.
Construction Management, 17 June
Government rolls out digital planning tool to all local authorities.
Your views needed - a strategy for the professions, trades and occupations.
Confronting competency, codes, capacity and costs.
The hidden risk in modern construction supply chains.
Construction Management, 10 June
24 months to 14: CITB launches accelerated apprenticeships.