The 11th International Conference on Urban Drainage Modelling (UDM) has been running since 1986 and in 2018 will be held the 11th edition, a monumental achievement of the urban drainage community. The UDM conference series started back in 1986 in Dubrovnik, former Yugoslavia. The second edition of UDM was organized in 1991 also in Dubrovnik. After the first two editions in Dubrovnik, the conference has travelled across the globe to the River Volga (1994), London (1998), Orlando (2001), Dresden (2004), Melbourne (2006), Tokyo (2009), Belgrade (2012) and Québec (2015). In 2018 we will be meeting in Europe once again. The UDM Conference deals with the main and advanced topics related to modelling the urban drainage system (e.g., water quality and quantity, urban flooding and modelling, urban flood forecasting and risk analysis, socio-economic interactions and modelling tools, etc… ) by focusing the attention on the interrelationship among the entire water cycle, environment and society. The UDM seeks to create a forum for promoting the discussion amongst scientists, professionals and academia on urban drainage thus providing to women and men of this field decisive ideas. We also hope that your participation to the Conference in Palermo will provide you the opportunity to explore the rest of Italy, to savor its diverse and rich mixture of ethnic traditions, culture, cuisine and religious sites. We look forward to welcoming you to the colorful and vibrant city of Palermo and see you in 2018.