Fred Sonnenwald - Research Student

Fred Sonnenwald

Telephone: 25768
Room: D105

email :

Research Group

Research Project

Identifying the Fundamental Retention Time Distributions of Urban Drainage Structures

Urban drainage is the process by which rainfall water is transported from the roof a building or a roadway to the receiving waters such as a river or lake. Involved in this process are various devices, including green roofs, manholes, and other sustainable urban drainage systems (SUDS). As the water passes through each of these devices it can be delayed and/or mixed. The Retention Time Distribution (RTD) is a way to characterize the delays or mixing that occurs for use in 1-D modelling.


In order to identify the RTD, a system identification technique called deconvolution is being used. Deconvolution results in a unique RTD particular to the system which was analysed. Current research focuses on developing a tool kit for deconvolution. The tool kit will then allow for the analysis of existing laboratory data. It is hoped that it will be possible to create a generalized the RTD so that it can be derived based on certain physical characteristics of a device. This could allow for the RTD to be used in large scale modelling packages, providing potentially enhanced simulation of device performance or water quality.


Fred is a recent graduate from the University of Sheffield with a Masters in Civil Engineering. His dissertation was on the real-time display of green roof run-off. (