The Effect of Hydrological and Anthropogenic Factors on the Chemical Properties of Water in the Canal Network of Southeastern Srem - Page 03

Material and Methods

Study Area and Monitoring Points

The research was conducted in southeastern Srem, Serbia. From a hydrological perspective, southeastern Srem (Fig. 1) is highly complex, with pronounced spatial and temporal variations in key hydrological parameters. Surface water and groundwater regimes in the study area are also complex and depend on both natural and anthropogenic drivers (Iron Gate 1 reservoir, operation of pumping stations within southeastern Srem, and a large number of radial wells along the Sava River).

 

Fig01
Figure 1: Location of southeastern Srem in Serbia and drainage areas of the Galovica and Petrac systems.

 

The drainage system of southeastern Srem was built to remove excess water and prevent water-logging. The excess water is evacuated either gravitationally or by pumping into the Sava River. There are two dominant drainage areas: Galovica and Petrac (Fig. 1).

The largest pumping station, Galovica (Fig. 2), is located at the confluence of the Galovica Canal and the Sava River. The total capacity of this pumping station is 24 m3/s (3x8 m3/s). In its immediate vicinity there is the Petrac pumping station, which evacuates water from the Petrac drainage area. Its capacity is 2x2.80 m3/s = 5.60 m3/s. It should be noted that there is a direct link between the two parallel canals, the Petrac and the Galovica, such that the Petrac PS can be used to remove excess water from both drainage areas. However, these two pumping stations can only evacuate excess water; they cannot pump fresh water from the Sava River into the drainage network. Such a capability exists only at the Novi Fenek pumping station (Fig. 2), which is a dual-purpose, reversible station. Due to its relatively low pump capacity (2x1.3 m3/s), the pumped water reaches relatively short stretches of the canals in the Petrac drainage area.

 

Fig02
Figure 2: Riverside area of southeastern Srem, including locations of pumping stations.

 

The Galovica drainage area is about seven times larger than the Petrac drainage area. The density of drainage canals in the Galovica drainage area is considerably higher, as shown in Fig. 3. General information about the drainage areas and drainage networks (size of drainage area, number of sub-areas, length of network, length of maincanal) is summarized in Table 1.

 

Fig03
Fig. 3: Canal networks in the Petrac and Galovica drainage areas.

 

Tab01

 

Apart from large differences between the sizes and canal lengths of the Galovica and Petrac drainage areas, there is a significant difference in water pollution. The Petrac drainage area is predominantly comprised of farmland, involving mainly diffuse sources as a result of application of fertilizers and irrigation. In the Galovica drainage area, apart from diffuse sources, there are point sources (discharges from a dairy, meat plant, sugar factory, animal farms, storm drains from the Nikola Tesla Airport, and outlets of insufficiently treated municipal wastewater, etc.).

 

Hydrological Assessment

The hydrological assessment of southeastern Srem included analyses of precipitation, evapotranspiration, drainage canal water levels, and stages of the Sava River. Precipitation characteristics and climate data were taken from the National Hydrometeorological Service of Serbia (climate station at Surčin, located within the study area).

Reference evapotranspiration was calculated applying the Penman-Monteith method (Allen et al., 1998). The stages of the Sava were gauged downstream from the Galovica and Petrac pumping stations. The water levels of the Galovica and Petrac canals were measured upstream from the pumping stations. Daily water level data recorded by means of staff gauges were taken from the Galovica Water Management Company.

 

Water Quality Testing

Two characteristic monitoring points were selected in the Petrac and Galovica drainage areas to compare the chemical properties of water, at locations wherethe greatest impact of pollution could be expected. They were monitoring point 5, located at the downstream end of the main canal in the Petrac drainage area, in the immediate vicinity of the Petrac PS (Fig. 4), and monitoring point 6 in the Galovica drainage area, downstream from the Village of Surčin, the most downstream point source of pollution.