title: Monitoring and statistical modelling of sedimentation in gully pots.
abstract: Gully pots are essential assets designed to relief the downstream system by trapping solids and attached pollutants suspended in runoff. This study applied a methodology to develop a quantitative gully pot sedimentation and blockage model. To this end, sediment bed level time series from 300 gully pots, spanning 15 months, were collected. A generalised linear mixed modelling (GLMM) approach was applied to model and quantify the accumulation of solids in gully pots and to identify relevant physical and catchment properties that influence the complex trapping processes. Results show that the retaining efficiency decreases as sediment bed levels increase. Two typical silting evolutions were identified. Approximately 5% of all gully pots experienced progressive silting, eventually resulting in a blockage. The other gully pots show stabilising sediment bed levels. The depth of the sand trap, elapsed time since cleaning and the road type were identified to be the main properties discriminating progressive accumulation from stabilising sediment bed levels. Furthermore, sediment bed levels exhibit no residual spatial correlation, indicating that the vulnerability to a blockage is reduced as adjacent gully pots provide a form of redundancy. The findings may aid to improve maintenance strategies in order to safeguard the performance of gully pots.
authors.affiliation: Section Sanitary Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, PO Box 5048, 2600 GA, Delft, The Netherlands. Electronic address: j.a.b.post@tudelft.nl.
authors.forename: J A B
authors.initials: JAB
authors.lastname: Post
authors.affiliation: Section Sanitary Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, PO Box 5048, 2600 GA, Delft, The Netherlands; Deltares, PO Box 177, 2600 MH, Delft, The Netherlands.
authors.forename: I W M
authors.initials: IWM
authors.lastname: Pothof
authors.affiliation: Waternet Foundation, PO Box 94370, 1090 GJ, Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Dirksen
authors.affiliation: Waternet Foundation, PO Box 94370, 1090 GJ, Amsterdam, The Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: Baars
authors.affiliation: Section Sanitary Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, PO Box 5048, 2600 GA, Delft, The Netherlands; Partners4urbanwater, Javastraat 104A, 6524 MJ, Nijmegen, The Netherlands.
authors.forename: J G
authors.initials: JG
authors.lastname: Langeveld
authors.affiliation: Section Sanitary Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, PO Box 5048, 2600 GA, Delft, The Netherlands; Deltares, PO Box 177, 2600 MH, Delft, The Netherlands.
authors.forename: F H L R
authors.initials: FHLR
authors.lastname: Clemens
mesh_terms: D062070:Hydrology / Q000379:methods*; D015233:Models, Statistical; D011336:Probability; D011897:Random Allocation; D015203:Reproducibility of Results
keywords: Bayesian inference; Generalised linear mixed modelling; Gully pot blockage; Sediment accumulation