PERSPECTIVES ON ENVIRONMENTAL MONITORING - AN INTRODUCTION TO THE UNITED-STATES-EPA LONG-TERM MONITORING (LTM) PROJECT

The U.S. Environmental Protection Agency's Long-Term Monitoring Project is a network implemented to study long-term changes in the chemistry of acid-sensitive surface waters in six regions of the U.S. The project was implemented in 1983 and has, not surprisingly, undergone various types of challenges and changes in each of the six regions. In this paper we describe five basic principles of monitoring network design that we believe are necessary (although not necessarily sufficient) for implementation and operation of a useful and professionally reputable network. The results of the first 9 yrs of the LTM Project, described in detail in the papers of this special issue, are here discussed in the context of these 5 principles.