Estimation of Uncertainty in Long-Term Sewer Sediment Predictions Using a Response Database

Regulations require U.K. water companies to reduce the number of properties at risk of sewer flooding. One of the potential causes of sewer flooding is the presence of persistent sediment deposits in sewers, such deposits are a common problem in many combined sewers. Although the regulations are risk based, there is a gap in the current knowledge on how the risk assessment is affected by the uncertainty in sewer sediment transport prediction. This paper describes the development of a methodology for estimating uncertainty in sewer sediment deposit depth predictions using existing empirically calibrated sediment load equations and Monte Carlo simulations combined with a response database. This methodology has been used to estimate the range of uncertainty of in-pipe deposit build-up predictions for a U.K. combined sewer system that suffered persistent deposition problems.

[1]  David Wotherspoon,et al.  The movement of cohesive sediment in a large combined sewer , 1994 .

[2]  M. Deaton,et al.  Response Surfaces: Designs and Analyses , 1989 .

[3]  Peter Ackers,et al.  Sediment Transport: New Approach and Analysis , 1973 .

[4]  Patrick Willems,et al.  Stochastic description of the rainfall input errors in lumped hydrological models , 2001 .

[5]  G Chebbo,et al.  Bayesian analysis for erosion modelling of sediments in combined sewer systems. , 2005, Water science and technology : a journal of the International Association on Water Pollution Research.

[6]  R. Harmon.  Geological Development of Panama , 2005 .

[7]  B. Wynne.  Uncertainty and environmental learning: reconceiving science and policy in the preventive paradigm. , 1992 .

[8]  L Benedetti,et al.  Assessment of WWTP design and upgrade options: balancing costs and risks of standards' exceedance. , 2006, Water science and technology : a journal of the International Association on Water Pollution Research.

[9]  P A Vanrolleghem,et al.  Development of a risk assessment based technique for design/retrofitting of WWTPs. , 2001, Water science and technology : a journal of the International Association on Water Pollution Research.

[10]  Patrick Willems.  Parsimonious pollutant washoff and sewer transport modelling , 2004 .

[11]  A. Bachoc,et al.  Trunk Sewer Clogging Development – Description and Solutions , 1992 .

[12]  D Bixio,et al.  A quantitative risk analysis tool for design/simulation of wastewater treatment plants. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[13]  M Mourad,et al.  Calibration and validation of multiple regression models for stormwater quality prediction: data partitioning, effect of dataset size and characteristics. , 2005, Water science and technology : a journal of the International Association on Water Pollution Research.

[14]  Adrian J. Saul,et al.  Validation of Existing Bed Load Transport Formulas using In-Sewer Sediment , 2003 .

[15]  Gabriele Freni,et al.  Identifiability analysis for receiving water body quality modelling , 2009, Environ. Model. Softw..

[16]  Sayan Gupta,et al.  Reliability Analysis of Flood Defences using Importance Sampling and Response Database with probabilistic loops in Large Hydraulic Models , 2005 .

[17]  R Ashley,et al.  Sewer solids-20 years of investigation. , 2005, Water science and technology : a journal of the International Association on Water Pollution Research.

[18]  D. Marquardt.  An Algorithm for Least-Squares Estimation of Nonlinear Parameters , 1963 .

[19]  J. L. Korving.  Probabilistic assessment of the performance of combined sewer systems , 2004 .

[20]  P. Willems.  Quantification and relative comparison of different types of uncertainties in sewer water quality modeling. , 2008, Water research.

[21]  Thorkild Hvitved-Jacobsen,et al.  Solids in Sewers , 2003 .

[22]  J. B. Ellis,et al.  Pollutional Aspects of Urban Runoff , 1986 .

[23]  Henrik Madsen,et al.  Fiction and reality in the modelling world – Balance between simplicity and complexity, calibration and identifiability, verification and falsification , 1999 .

[24]  G Chebbo,et al.  A benchmark methodology for managing uncertainties in urban runoff quality models. , 2005, Water science and technology : a journal of the International Association on Water Pollution Research.

[25]  J L Bertrand-Krajewski,et al.  Long term monitoring of sewer sediment accumulation and flushing experiments in a man-entry sewer. , 2006, Water science and technology : a journal of the International Association on Water Pollution Research.