TIME (Temporally Integrated Monitoring of Ecosystems) is a statistically selected population of lakes in New Eng- land and the Hudson Valley (31 lakes) and the Adirondacks (43 lakes) that were selected from the original 1991 EMAP-SW (Environmental Monitoring and Assessment Program–Surface Waters) population with acid neutralizing capacity less than 100 meq/L (Young & Stoddard 1996). Samples are taken annually, during a summer base-flow ‘index period’. This sampling strategy is used to reduce hydrologic impact on water chemistry and hence provide an assessment of trends in chemistry with the least number of samples (e.g., Stoddard et al. 2003).
The EMAP program sampled these lakes and many others one or more times between 1991-1994. As part of EMAP, the lakes were characterized with respect to landscape features, hydrology, geology, and chemistry as well as biological studies (fish, breeding birds, zooplankton) and a paleo-limnological coring study to reconstruct pH and other variables. The program was discontinued, but some sampling of the lakes continued through other funding sources during the hiatus. In 1999, the TIME project officially began, with a goal of assessing the effectiveness of the Clean Air Act Amendments of 1990 at reducing acidification of surface waters (Stoddard et al. 2003, Kahl et al. 2004). As of this writing, the lakes have records spanning two decades or more.
Nelson, S.J., A.J. Baumann, A. Coffin, K. Johnson, C. Schmitt, K. Strock. 2013. Lake Site Assessments: US EPA TIME-New England Lakes. Report to US-EPA. 142 pp.
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