KNEE DEEP follows a culturally diverse group of dedicated senior citizens who are pooling their collective knowledge for a common cause: the environmental health of the Delaware Valley's waterways. The Center in the Park Senior Environment Corps is quietly generating scientific data that someday will feed into a global database documenting the long-term health of the world’s rivers and streams, and possibly spur changes in the management of water and waste. The documentary also highlights how the volunteer organization prioritized environmental education within their community, particularly with schoolchildren.