Case Study Selection Process
3.1 Climate change and water crises in the Upper Iskar
At 368 km, the Iskar River, situated in the south west part of the country, is Bulgaria’s longest river. It has the third largest catchment area (8.650 km²) of all Bulgarian rivers after the Maritsa River and the Struma River. The case study sub-catchment, shown in the map in Figure 3.1 (below), begins at the river’s spring in the Rila Mountains and ends at the point where the Lesnovska River joins the Iskar from the east, approximately 1 km north of Sofia.
The hydrologic cycle in the Upper Iskar is characterised by seasonal extremes, with intermittent drought during the summer on the one hand, and flooding in the autumn
Figure 3.1. Land use map of the Upper Iskar test site showing the Iskar reservoir and Sofia city.
and winter on the other. The Iskar River begins 2000 feet above sea level in the Rila Mountains which, being below the altitude at which glaciers form, means there is no permanent ice. During the winter months snow accumulates in the mountains, and during the spring when the snow melts, it becomes the most important annual source of water in the region, replenishing reservoir levels for the summer months.
The Iskar Dam is the largest reservoir in the Upper Iskar and the main source of water supply for the city of Sofia, supplying 80% of all water consumed in the city.
The histogram below, Figure 3.2, shows the mean monthly water inflow to the Iskar Dam for the years 1990 to 1995. It shows that around 50% of the annual recharge of the Iskar reservoir occurs between April and June, and is evidence that the main recharge event in the year is spring snow-melt.
Between 1993 and 1995 citizens of Sofia experienced severe water crises due to water scarcity. Studies into snow-cover in the Rila Mountains from 1921-2000 (Petkov and Koleva, 2005; Petkova et al., 2005) conclude that “during recent years, especially in the period 1982-1994, the number of days with snow cover decreased, whilst on the other hand, winter temperatures increased in the same period”.
Sofia
Iskar reservoir
Samakov
Map supplied by Geonardo, 2005
Figure 3.2. Average monthly inflow, Iskar reservoir: 1990-1995
As well as the annual cycle of variable water availability hydrologists have identified a longer cycle spanning a period of 20-30 years in the region (Alexander and Genev, 2003). Knight et al. (2003) explain that the Upper Iskar sub-catchment is situated on a plain between two mountain ranges – the Rhodope and Balkan ranges – which lies within a latitudinal range that is characterised by drought (Knight et al., 2003) and cite these geographical factors as causes of a long-term cycle between water scarcity and inundation experienced in the region. The cycle is evident in the graph below, Figure 3.3, which shows precipitation anomalies from the mean calculated from data collected between 1900 and 2000. From this data hydrologists have identified a
“natural hydrologic regime that consists of a 10-15 year period characterised predominantly by flooding, followed by a 10-15 year period characterised by drought.” (Knight et al., 2003, p117)
0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Month
Mm3
Data source: Bulgarian Academy of Sciences, 2006
Figure 3.3. Precipitation in the Upper Iskar – variation in actual precipitation from the mean for the years 1900 to 2000. The graph illustrates the long-term cycle of flood and
drought in the upper Iskar
Climate change modelling for the region has been reported by Chang et al. (2002).
They compared two simulation models, one from the United Kingdom Meteorological Office Hadley Centre for climate change prediction and research (HadCM2) and a second from the Canadian Centre for Climate Modelling and Analysis (CCC). Chang et al. simulated water resources scenarios into a water balance model for a study area, the Sturma River, the results of which are highly relevant to the Upper Iskar because the grid squares used in the study are 20.625oE ~ 24.375o E / 41.25o N ~ 43.75oN and 20.625oE ~ 24.375oE / 40.8026oN ~ 44.5526oN for the HadCM2 and CCC models respectively, which incorporates the Upper Iskar river catchment. The table below, Table 3.2, summarises the results of the HadCM2 and CCC climate simulations for the Sturma River for 2025 and 2050.
The most notable forecasted variations from the ‘base’ stream flow, which used data from 1961-1990, are the decrease in run-off during the summer, and the increase in run-off during the winter, a characteristic of the forecast that is repeated in both HadCM2 and CCC models. It should be noted that the data used in the simulations did not include the years of the most recent and severe water crisis, 1993-1995.
-50 -40 -30 -20 -10 0 10 20 30 40 50
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
Precipitationanomalies(%)
Observed run. average
Data source: Alexander and Genev, 2003
Table 3.2. Changes in seasonal and annual stream-flow in Rila mountains (unit m3/sec) SCENARIO SPRING SUMMER FALL WINTER ANNUAL
Base 145 78 33 74 83
HadCM2 (2025) 151 70 31 96 87
CCC (2025) 167 74 34 108 96
HadCM2 (2085) 129 43 22 117 78
CCC (2085) 151 40 27 149 92
Data source: Chang et al (2002)
These climate predictions indicate that the magnitude of the fluctuation between water shortages and inundations is likely to increase during the next 80 years. The forecasts should be considered in light of the water crisis experienced following the major drought event of 1993-1995, and more recent flood events, both described below. They signal an urgent need for mitigation measures to avoid water stress in the long-term.
The following section describes the social, economic and political context within which water resources management has taken place in the Upper Iskar during the passed 30 years.
3.1.1 Water management during the transition period (1989-1995)
The transition of the political system in parallel with the drive for economic development has come to bear on water resources management in the Upper Iskar.
Some commentators (Knight et al., 2003; Clarke and Wang, 2003) have suggested that it was the drive for economic development that led water managers to favour supply-side options in favour of demand-side options to address water scarcity. One result is that most of the Upper Iskar’s water resources now flow through a complex network of channels and pipelines the city of Sofia. The map below, Figure 3.4, shows the complex network of pipelines and channels that supply water to the city of Sofia. It shows hydrologic structures such as the Rila, Boyana and Iskar pipelines that supply the city from two main reservoirs, the Beli Iskar and Iskar Dams, with water from the Rila Mountains, as well as potable water treatment plants and hydro-power plants.
Figure 3.4. Map of water supply network and hydrological structures for the city of Sofia
The democratisation of the pre-1989 Communist Government resulted in socio-economic changes, and also conflicts over water due to the construction of water diversion projects. The controversy surrounding the Djerman-Skakavitsa water diversion project (Figure 3.4), in the period 1989-1991, is a case in point. Water management activities driven by economic development came into conflict with the interests of sections of society in the rural regions adjacent to a major river upstream of Sofia. The changes were driven by the change in the political system. While the situation in the Bulgarian capital had been difficult in terms of both economic growth and the state of the urban infrastructure, it was even more difficult in the rural
“provinces”. Rural development under central planning had traditionally been oriented towards the industrialisation of agriculture (through the state farms) and the extensive exploitation of natural resources (Hristov et al., 1972; Staddon, 1999). Both sectors were hard hit after 1989, when democratisation of the formerly Communist
Source: Knight et al., 2003
Government began, and rapid disinvestment and plant closures occurred in rural areas. Rural unemployment rates were close to double those prevalent in the urban core, a situation made worse by the disinvestment of industrial capital away from rural areas as conglomerates formed behind larger core production units in urban areas (Begg and Pickles, 1998). The communist era’s “social industries” policy, which sought to locate some ongoing industrial employment in even the smallest villages, effectively collapsed. This was the case in Sapareva Banya where, in 1991, protests were held against the diversion project, and where as many as 25% of North Rilans were unemployed, having been let go from the soft coal operations at Bobov Dol or other smaller local industrial plants as successive waves of plant closures overwhelmed the state sector after 1989 (Staddon, 1996). The scale of the water diversion project which involved the diversion of surface waters from the Vitosha, Rila and western Rhodope massifs, to the capital, Sofia, is remarkable in European terms, encompassing an area of more than 5000 km2 immediately south of the Sofia Basin. By 1989 this plan had already been partially constructed, with the Djerman-Skakavitsa Diversion in the North Rila Mountains earmarked as the next phase of its realisation.
In February 1991 the Bulgarian government sent Interior Ministry troops into the picturesque town of Sapareva Banya on the northern slopes of the Rila Mountains to quell popular protest against the Djerman-Skakavitsa Diversion designed to help alleviate a water shortage in the capital. This protest pitted residents of the water-scarce capital against North Rila communities fearful of potential environmental damage and angered by the lack of government consultation and dialogue (Knight et al., 2003).
3.1.2 Changes in the management of the municipal water supply
The ownership of Sofia’s municipal water supply network passed to a concession in 2000. The company Sofiiska voda Ltd, now has a 25-year concession contract for provision of water, sewerage and wastewater treatment services in the city of Sofia.
75% is owned by United Utilities (UU) and the European Bank for Reconstruction and Development (EBRD), while 25% is owned by the public water supply and sewerage company ViK Sofia. Sofiiska voda Ltd manages the water supply and sewerage system of Sofia, and supplies a population of approximately 1.3 million (20% of the population of Bulgaria). It uses two water supply sources – the Iskar Dam (655 million m3 / yr) and Beli Iskar dam (15 million m3 / yr). It also operates more than 90 city reservoirs, 4,100 km water distribution network, 147 000 service connections, 2 000
km sewer network, 1 waste water treatment plant, and two large potable water treatment plants - Bistritza (capacity 6.75 m3/sec) and Pancharevo (capacity 4.5 m3/sec).
Variation and uncertainty in the hydrological regime and socio-economic and political change characterize water management challenges in the Upper Iskar region were identified above as drivers of water stress. The recent introduction of the private sector in managing domestic supplies has further implications for change in the way water is managed in the region.
The following section describes the first field work activities carried out in the city of Sofia which involved interviews with experts in water demand management to
‘ground truth’ models.