Series: Green Roads Webinar Series Practical Tools for Climate-Resilient Road Drainage: Design Tools and Culvert Sizing Calculator 27 August 2026 [The webinar recording will be uploaded after the webinar] Road drainage failure is a leading cause of road disruption and rising maintenance costs across Asia and the Pacific, and rainfall assumptions used in the past are becoming less reliable as storms intensify. This webinar presented practical tools developed through ADB-supported work in Timor-Leste: a Drainage Design Tool and a Culvert Sizing Calculator. These tools show how rainfall, catchment characteristics, climate allowances, and blockage assumptions translate into consistent, climate-informed drainage decisions. Download the Cross Drainage Culvert Sizing Tool and the Drainage Blockage Potential Tool here. Program and Learning Materials Disclaimer The views expressed on this website are those of the authors and do not necessarily reflect the views and policies of the Asian Development Bank (ADB) or its Board of Governors or the governments they represent. ADB does not guarantee the accuracy of the data included in this publication and accepts no responsibility for any consequence of their use. By making any designation of or reference to a particular territory or geographic area, or by using the term “country” in this document, ADB does not intend to make any judgments as to the legal or other status of any territory or area. Event Coordinator/s Michael Anyala Topics Transport