Monitoring and statistical modelling of the solids accumulation rate in gully pots

ABSTRACT

Gully pots are utilized for conveying runoff to drainage systems, as well as for reducing the system’s solids loading by retaining suspended solids. However, the accumulation of solids in gully pots reduces their removal efficiency, leading to an increase in solids transport towards the drainage system. This article aims to identify the main drivers of the solids accumulation in gully pots and, thus the relevant processes for wash-off models. The solids accumulation rates in 407 gully pots were monitored within a period of ~14 months and were analysed by means of a linear mixed model and a regression tree. The parameters vegetation factor, rainfall volume, and filling degree are the main drivers of the accumulation process. These parameters are linked to the solids build-up in a catchment, solids transport, and solids retention in gully pots, which means that none of these 3 processes is dominant.

KEYWORDS:

• Gully pot
• catch basin
• maintenance
• solids
• urban drainage
• field data

Acknowledgements

The authors thank the municipalities of Rotterdam and Den Haag for providing the measurement locations and practical help. They thank Nadia Mobron, André Vallendar, and Cédric Zigault who have been working on this project as part of their study curriculum.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed here

Notes

1. The measured depth is dependent on the gas fraction and the compressibility of the bed, by compressing the sediment before the depth measurement, which improves the reproducibility of the measurement.

2. Whenever possible the cause of the outliers was identified using the logbooks or other circumstantial evidence that exceptional situations occurred.

Additional information

Funding

The research is performed within the Dutch ‘Kennisprogramma Urban Drainage’ (Knowledge Programme Urban Drainage). The involved parties are: ARCADIS, Deltares, Evides, Gemeente Almere, Gemeente Arnhem, Gemeente Breda, Gemeente Den Haag, Gemeentewerken Rotterdam, Gemeente Utrecht, GMB Rioleringstechniek, KWR Watercycle Research Institute, Royal HaskoningDHV, Stichting RIONED, STOWA, Sweco, Tauw, vandervalk+degroot, Waterschap De Dommel, Waternet and Witteveen+Bos