Flow exchange, energy losses and pollutant transport in a surcharging manhole linked to street profiles

Matteo Rubinato, Louis Helms, Matthew Vanderlinden, James Hart, Ricardo Martins

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11 Citations (Scopus)
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Due to the increased frequency and magnitude of urban flooding events, there is a pressing need to improve the accuracy of numerical tools to better assess the hydraulic performance of new drainage systems. Nowadays, such models are inherently challenging to verify due to the difficulty of acquiring reliable data during the flood event, meaning that most models are calibrated using only an estimated measure of the extent of flooding. To address this gap, this study investigated flooding scenarios using an experimental scale facility of an urban street and manhole network, delivering a novel data-set in terms of the scale of the facility used. Several hydraulic conditions are investigated within a variety of street configurations incorporating parking slots, cars on the road and various locations of the manhole within the street. This enabled the quantification of flow exchange during hypothetical flood events for multiple cases, as well as the characterisation of energy losses, a crucial parameter that is often a source of uncertainty within numerical modelling tools. Furthermore, the experimental system was equipped with an injection system to replicate the transport of pollutants during flooding events, and this enabled the estimation of the exchange of soluble pollutants between the minor and major systems for each flooding scenario. Results obtained have confirmed the applicability of the orifice equation for the estimation of flow exchange between the two systems, showing that i) the discharge coefficients obtained (0.126–0.138) decrease as the width of the street/channel becomes narrower, ii) the surface energy loss coefficient was unaffected by all street configurations tested, iii) all tested geometries displayed significant pollutant exchange from the sewer to the street, in the range of 28–39%, demonstrating that situating the manhole closer to the edge of the street increased the mass of pollutants being exchanged to the surface and the presence of parking spaces alone did not appear to affect the mass of pollutant exchanged. These results have provided a novel series of datasets (including flowrates, flow exchange, energy losses and discharge coefficients) that could be used to calibrate and validate numerical models and be utilised as a benchmark.
Original languageEnglish
Article number127201
Number of pages17
JournalJournal of Hydrology
Early online date14 Nov 2021
Publication statusPublished - Jan 2022

Bibliographical note

This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).


This research was funded by EPSRC through the grant with the reference EP/ K040405/1. The experiments were conducted by Dr Rubinato within the experimental facility he developed for his PhD in the Water Laboratory of the Civil and Structural Engineering Department of the University of Sheffield. Dr Martins acknowledges the financial support of FCT, Portugal, through the Projects ASHMOB (CENTRO-01-0145-FEDER-029351) funded by FEDER, through COMPETE2020 - POCI, and by national funds (OE), through FCT/MCTES, and to the FCT/MCTES strategic projects UIDP/50017/2020 + UIDB/50017/2020 granted to CESAM.


  • Drainage systems
  • Flow exchange
  • Head losses
  • Pollutant transport
  • Sewer/Surface flow interactions
  • Urban flooding

ASJC Scopus subject areas

  • Water Science and Technology


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