2.2.2 Salinity
Because data collected through the NCDMF monitoring program may have
preferential sampling bias, we sought to analyze additional salinity
data collected from an unbiased monitoring program in order to
understand how the NCDMF observations compared to an independent
dataset. We accessed the North Carolina Division of Water Resources
(NCDWR) Water Quality Portal (Water Quality Portal, 2021). The NCDWR
dataset consists of 17 monitoring stations that had at least 10 years of
salinity data between the years 1999 and 2021 and were within proximity
to the NCDMF water quality sampling stations (Figure 2); stations with
fewer than 10 years of data or in portions of the estuary that did not
overlap with NCDMF stations (e.g., fresh headwaters) were not considered
in the analysis. However, data from NCDWR sites in SGAs D and E were
still considered despite being relatively distant from NCDMF monitoring
locations as these were the only NCDWR sites present in SGAs D and E.