Statistical Analysis of Trends in the Red River Over a 45 Year Period

Table 3.1: Defined Seasons.
Season Months Description
Spring February - March rising limb of hydrograph
Summer April - May peak streamflow
Fall June - August falling limb of hydrograph
Winter September - January low flow, ice-cover period
Concentrations of dissolved calcium (Figure 3.2) are quite similar between the
three stations however data were sparse at the south floodway near St. Norbert and
the Selkirk monitoring stations. At the Emerson monitoring station the boxplot is
symmetric and takes the appearance of an approximately normal distribution. Concentrations
of dissolved sodium (see appendix Figure A.2) appear to be extremely
skewed to the right with a few outlying observations with a maximum value at 305.0
mg/l and high values of dissolved sodium occurring from November 1988 through
January 1989. The median values of the concentrations of dissolved potassium and
magnesium (see appendix Figures A.3 and A.4) are similar between stations and
follow an approximately normal distribution at the Emerson station. There is more
data for the analysis of the concentrations of dissolved sulphate at the south floodway
near St. Norbert and Selkirk monitoring stations (see appendix Figure A.5)
than the previous constituents. The Emerson station exhibits the greatest degree
of variability amongst the three stations possessing values from 4.0 mg/l to 1050.0
mg./l of dissolved sulphate.
Concentrations of dissolved calcium have median concentrations between 56.3
mg/l and 73.0 mg/l and range from 4.60 mg/l to 130.0 mg/l with few evident outliers.
The median and mean concentration of dissolved sodium are similar amongst
the stations, however the Emerson station exhibit values ranging from 1.70 mg/l to
305.0 mg/l, this can be indicative of seasonal change and change in flow rate. The
medians and means for the concentrations of dissolved sulphate are much higher at
the Selkirk monitoring station compared with the Emerson and south floodway near
St. Norbert stations. Total dissolved solids which are calculated by summing the
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