Piers Clark Keywords Piers Clark Isle Group water waste and utilities wastewater Read more about Piers Clark Piers has more than 25 years of experience in the water, waste, and utilities sectors. He is the Founder and Chairman of the Isle Group Ltd, a technical, strategy, and innovation consultancy which serves over 200 utilities around the world. Piers was previously Asset Management Director and Commercial Director at Thames Water, one of Europe’s largest water and wastewater companies.