Purpose: The environmental logistics impact is significant in urban areas, characterised by high receptor den- sities, less accessible sites and limited storage space. With the aim to reduce negative externalities generated by urban construction transport and improve the use of existing inland waterway transport (IWT) infrastructure, the City of Brussels has implemented a water-bound Construction Consolidation Centre ((BCCC). While the concept of a CCC has been implemented in different European cities, limited impact studies are available. This paper assesses the environmental off-site road and IWT’s transport performance of the multimodal BCCC case. Design/methodology/approach: The sustainability impact is evaluated using economic external cost calculations, contextualised with transport planning indicators. Subsequently, findings are compared to business-as-usual (BAU) operations without a CCC as part of a scenario evaluation, for the 24 large construction sites supplied through the CCC between Sep-2019 and Dec-2020.

Findings: Improvements in the IWT sector are necessary to tackle local emissions (NOx, PM) which rise signifi- cantly compared to BAU (+257 %), mainly attributable to less performant -yet ubiquitous- vessel engines and their long running life. In contrast, other externalities decrease, most noticeably on congestion costs (-91 %), climate change (-66 %), noise (-79 %) and infrastructure costs (-60 %). Overall, €49,404.67 of external costs are saved annually, a 58.72 % reduction compared to BAU. Additionally, improvements are observed on transport planning and efficiency, with 73 % timely deliveries and 93.32 % delivery compliance, hence respecting the Just- In-Time and Just-In-Place principles.

Research limitations/implications: Promising results are shown to incentivize industry and policy makers for adopting a CCC in light of alleviating the impact of urban construction logistics (CL), if the overall external costs and mobility impacts are considered. Results should be further compared to other logistic solutions to evaluate complementary measures, including more differentiated scenario evaluations.

Practical implications: Although IWT alleviates road network use, air pollution from vessels should be addressed. An IWT-CCC can offer decision-makers a transport planning solution to decrease urban nuisances and increase resource efficiency use, if specific IWT-CCC and CL applicability requirements are considered. Originality/value: This paper adds knowledge to the sector’s impact mitigation potential using IWT-CCC, offering insights for decisional support and policy recommendations.