The Upper Tisa Valley. Preparatory proposal for Ramsay

Figure 12. Annual peak streamflows (annual data, five year moving average, linear
trend) past the Tivadar station on the Tisa (1950 1994)
The reservoirs built in the Nyírség Region and at Szabolcsveresmart in the
1960s and 1970s reduce the gap between the demand and supplies but slightly, the
total storage capacity in the region being 37 million m 3 only.
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Water quality over the Hungarian Tisa section
Under normal conditions the DO level is high along the entire river section,
even the lowest levels observed at the stations meeting the criteria of good (Class II)
quality. During algal blooms in the summer months the water may become over
saturated with oxygen. The concentration of organic in terms of oxygen consumption
increases slightly below the entrance of the tributaries, but does not surpass the limit
value of the acceptable category at any of the stations. The peak oxygen consumption
levels measured by the dichromate method which indicate a high organic load, Class
IV V water quality coincide with the passage of flood waves.
The oxygen parameters show a slight improvement at the Záhony and Balsa
stations.
The average and maximum concentrations of ammonium nitrogen are below
the limit values of good water quality at all sampling stations. In terms of the average
nitrite nitrogen parameters the water is of excellent quality and acceptable in terms of
the peak values. Not even the highest nitrate nitrogen levels exceed the limit value of
good water quality. The concentration of inorganic nitrogen is typically low in Tisa