Streamflow Statistic Trends at USGS Streamgages within the Chesapeake Bay Watershed (1940-2018)

This Child Item contains (1) a table of trends in eight annual streamflow statistics for the time periods 1940-1969, 1970-1999, and 2000-2018, and
(2) a .zip file of plots of the eight statistical trends for the three time periods.
The annual streamflow statistics and their trends were computed by Climate Year (CY) for 1-,7- and 30-day minima and by Water Year (WY) for 1-,7- and 30-day maxima, median and mean.
Streamgages from the original dataset (n = 409) were excluded from one or more time periods of analysis because of extensive data gaps that would interrupt trend lines;
therefore, streamgages were indexed into the earliest possible time period relative to their installation date
(for example, a streamgage with an operating start year of 1958 would be included in the analysis for the time periods 1970-1999 and 2000-2018), which resulted in different sample sizes for each period:
1940-1969 (n = 90), 1970-1999 (n = 167), and 2000-2018 (n = 243).
Similarly, multiple streamgages were wholly excluded because of frequent discontinuities in the daily mean streamflow used to derive the annual mean streamflow through all three time periods.