Kledyński is a graduate of Warsaw University of Technology, specializing in hydrotechnics. He holds the title of Professor of Technical Sciences and is an expert in hydraulic engineering, water engineering, and environmental engineering. He works at Warsaw University of Technology, where he served as the director of the Institute of Water Supply and Water Management from 1997 to 2005. He also led the Department of Hydraulic Engineering from 2006 to 2007 and the Department of Hydraulic Engineering and Hydraulics from 2007 to 2011. He was the dean of the Faculty of Environmental Engineering from 2005 to 2008 and served as the vice-rector for general affairs at Warsaw University of Technology from 2012 to 2016.

In the Polish Chamber of Civil Engineers, he chaired the National Qualification Committee from 2002 to 2004, served as vice president from 2010 to 2018, and was president from 2018 to 2022.

He is a member of numerous expert and scientific bodies, including the Global Water Partnership – Poland (since 2001), the National Water Management Council at the Ministry of Environment (deputy chairman from 2002 to 2010, member from 2011 to 2015), the Committee on Civil and Water Engineering of the Polish Academy of Sciences (vice chairman from 2007 to 2015, member since 2016), the Committee on Water Management of the Polish Academy of Sciences (2011-2014), the Committee on Research on Water-Related Hazards of the Polish Academy of Sciences (2011-2013), the Association of Water and Land Reclamation Engineers and Technicians (since 1983, vice president from 2001 to 2005), the Polish Scientific and Technical Committee of the Polish Association of Sanitary and Environmental Engineering (since 2005), the Program Council of the “Gospodarka Wodna” monthly magazine (vice chairman from 2007 to 2019, chairman since 2019), the Society of Hydroelectric Power Plants (since 2001), the Polish Committee of the International Commission on Large Dams POLCOLD (2004-2021), and the Expert Council of the Municipal Water and Sewerage Company in Warsaw.

He has been honored with ministerial awards, including the Minister of the Environment’s Award for Merit in Environmental Protection and Water Management (2006), the Minister of Economy’s Award for Merit in the Development of the Polish Economy (2015), and the Minister of Infrastructure and Construction’s Award for Merit in Construction (2016). He has also received numerous awards from professional organizations, including the Polish Association of Water and Land Reclamation Engineers and Technicians (SITWM) and the Polish Chamber of Civil Engineers (PIIB).