National Surface Water Survey: Eastern Lake Survey-Phase II Combined datasets: Spring (SPSFIM01), Summer (SUSFIM01), Fall (FASFIM01), Summer Chlorophyll (SUSCHLA), and Bathymetry data (BATHYM_M), 1986

The Eastern Lake Survey-Phase II (ELS-II), conducted in the spring, summer and fall of
1986. The focus of ELS-II was on the northeastern United States. ELS-II involved the resampling
of a subset of lakes in the northeastern United States sampled in ELS-I to determine chemical
variability and biological status. Furthermore, within-indexed period variability was examined
in the fall of 1986 to provide insight concerning the ability to detect chemical changes over
time, and the precision of the estimates of the number of acidic lakes from Phase I. The primary
objectives of ELS-II were (1) to assess the sampling error associated with the ELS-I fall index
sample, (2) to estimate the number of lakes with low acid neutralizing capacity (ANC) (i.e.
potentially susceptible) that are not acidic in the fall but that are acidic in other seasons,
and (3) to establish seasonal water chemistry characteristics among lakes. This data set is part
of the National Surface Water Survey (NSWS) and the National Acid Precipitation Assessment
Program (NAPAP). The data set contributes to the quantification of the extent, location, and
characteristics of sensitive and acidic lakes and streams in the eastern United States sampled
during the spring, summer and fall seasons.