| Strymon is a
transboundary river of Greece, Bulgaria and Former Yugoslav Republic of
Macedonia (FYROM) in southeastern Europe. Water quality
parameters and the discharge have been monitored each month just 10 km
downstream of the river’s entry into Greece. The data of nine
water quality variables (T, ECw, DO, SO42-,
Na++K+, Mg2+ , Ca2+, NO3‾,
TP) and the discharge for the period 1980-1997 were selected for this
analysis. In this paper a) the time series of monthly values of water
quality parameters and the discharge were analysed using statistical methods,
b) the existence of trends and the evaluation of the best fitted models
were performed and c) the relationships between concentration and
loads of constituents both with the discharge were also examined. Boxplots for
summarising the distribution of a data set were used. The χ2-test
and the Kolmogorov-Smirnov test were used to select the theoretical
distribution which best fitted the data. Simple regression was used
to examine the concentration-discharge and the load-discharge relationships.
According to the correlation coefficient (r) values the relation
between concentrations and discharge is weak (r< 0.592) while the
relation between loads and discharge is very strong (r > 0.902).
Trends were detected using the nonparametric Spearman’s
criterion upon the data for the variables: Q, ECw, DO, SO42-,
Na++K+ and NO3‾
on which temporal trend analysis was performed.
Keywords: Strymon river, water quality, discharge, concentration, load,
statistics, trends |