To provide a forum for discussion of recent advances in the studies of chemical episodes in lakes and streams was the purpose of “Episodic Chemical Changes in Streams and Lakes as Related to Acidic Deposition,“ a Hydrology section session at the 1990 AGU Fall Meeting in San Francisco. The session was cochaired by M. Robbins Church and Keith Eshleman.
In recent years this topic has been of special concern to federal and state regulatory agencies because of the demonstrated contribution of acidic deposition to chemical episodes (via heavy rainstorms or snow-melts) with consequent adverse effects on aquatic biota. With heightened public and regulatory agency concern has come increased funding for this topic and consequent advances in scientific understanding. We hosted a similar session at the 1989 AGU Fall Meeting, which drew some 36 oral and poster presentations. Work has continued apace in this field and the 1990 session drew 12 oral presentations and 9 posters.