Assessment of the Microbial Pollution of the Olympic Rowing and Canoeing Center at Schinias through Mathematical Modeling

The Olympic Rowing and Canoeing Center constructed at Schinias, accommodated the
rowing and canoe – kayak sprint competition of the 2004 summer Olympic Games. This
paper presents the results of a study which aimed at assessing the water quality
characteristics, regarding microbial pollution, of the Olympic rowing and canoeing Center in
relation to alternative inflows scenarios. The study was conducted by using a microbial –
pollution model which describes both physical transport phenomena and biological and
chemical reactions taking place in the water body. Moreover, the mathematical model
incorporates a stochastic approach (based on Monte Carlo technique) in order to take into
account the random variation of the input variables, such as the pollution loads and the
intensity of the solar radiation, which is an essential factor for the fate of faecal coliforms.
The mathematical model takes into consideration the random fluctuation of the constants and
the model’s input data, by creating a range of possible values for each one of them and a
corresponding probability distribution. As a result of this kind of stochastic approach, the
model predicts the concentration of faecal coliforms, not as a single value, but as a set of
possible values. A statistical analysis of this set of values, allows for the estimation of
statistical data like characteristic values that will not be exceeded for given confidence levels.
The mathematical model was applied for a wide range of the monthly inflows entering the
rowing center through the leading channel, which fully cover the discharges of Makaria spring
for three alternative typical hydrologic years (a particularly wet, a particularly dry and a mean
hydrological year).
From the application of the model for several flow patterns into the course it was concluded
that the flow pattern does not affect significantly the spatial and temporal distribution of the
concentration of the faecal coliforms, since dispersion is the governing transport mechanism
in the rowing course. The highest concentrations are observed in an area close to the inlet
point of the leading channel, while in areas located in a longer distance the concentrations are
decreasing.
According to the results of the model the anticipated concentration of faecal coliforms, in
relation to the proposed revision of the 76/160 European Directive on bathing waters, is lower
than 250FC/100ml for the 95% of the samples and thus the rowing and canoeing center is
sorted in the category of excellent quality waters.