NEW: Annual Report - George Mason University

66
Chloride (mg/L)
350
300
250
200
150
100
50
Station 7: June-Sept
1980 1985 1990 1995 2000 2005
YEAR
Chloride levels were clustered
in a narrow range just under
50 mg/L for the entire study
period (Figure 70). Higher
values observed in some years
were probably due to the
estuarine water intrusions that
occur in dry years. The trend
line indicated a slight decline
in recent years, but a linear
regression demonstrated a
significant linear increase in
chloride over the study period
at a rate of about 1 mg/L per
year (Table 11).
Figure 70. Long term trend in Chloride (NC Lab Data). Station 7. Gunston Cove.
Chloride (mg/L)
400
300
200
100
Station 9: June-Sept
1980 1985 1990 1995 2000 2005
YEAR
Chloride in the river has been
slightly more variable than in
the cove (Figure 71). The
higher readings are again due
to brackish water intrusions in
dry years. A slight trend of
increasing values in the
1980’s and decreases in the
late 1990’s and 2000’s was
suggested by the trend line.
Regression analysis revealed
a significant linear increase of
about 1 mg/L per year (Table
11).
Figure 71. Long term trend in Chloride (NC Lab Data). Station 9. River mainstem.