This is the second webinar presented by IAEA Legacy Trench Site Community of Practice (CoP). The webinar will introduce the overall approach and good practices gathered from the ‘LeTrench’ project regarding the environmental modelling and assessment of legacy trench sites. The case study will present the UK experience from the Low Level Waste Repository and explain the approach to accounting for the legacy trenches within the Site Wide Environmental Safety Case. The panelist will discuss their major challenges and take questions from the webinar participants.