The Athalie Richardson Irvine Clarke Prize, or “Clarke Prize”, is awarded annually by the National Water Research Institute (NWRI) of Fountain Valley, California. It consists of a medallion and $50,000 award for demonstrated excellence in the fields of water science and technology. It recognizes the highest contributions by an individual engaged in the discovery, development, improvement, or understanding of the issues associated with water quality, quantity, technology, or public policy.