On the Flood Forecasting at the Bulgarian Part Of
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BALWOIS 2004 Ohrid, FY Republic of Macedonia, 25-29 May 2004 Waters In The Mountain Vitosha – Description, Quality, Protection Vesela Rajnova, Stefka Blaskova, Julia Kirova, Plamen Ninov National Institute of Meteorology and Hydrology Sofia, Bulgaria Abstract The Vitosha Mountain co-exists as a comparatively high mountain (maximum altitude – 2290 m) and at the same time as a park near the more then one million city of Sofia – capital of Bulgaria. The advance of the urbanizing processes upper on the slopes of the mountain requires new investigations revealing the actual condition of the waters and imposing plans for new protection activities concerning waters’ conservation. In the present material a detailed description of the existing surface and ground waters in the mountain is done. On the base of expeditions carried out the last years is prepared an assessment of the water quality on the main hydrochemical parameters reflecting the actual condition and analyzing the influence of the process of urbanization. Some recommendations concerning water protection are presented with a view to running processes of mountain resources exploitation. Key words: water quality, protection, mountain ecology Vitosha and its surface and ground waters The issue of the waters in the Mountain Vitosha, their quality and protection was and will be a priority for the citizens of the city. The advance of the urbanizing processes upper on the slopes of the mountain requires new investigations revealing the actual condition of the waters and imposing plans for new protection activities concerning waters conservation. From this point of view the surface and ground water pollution is an actual problem not enough clarified. The Mountain Vitosha co-exists as a comparatively high mountain (maximum altitude – 2290m) and at the same time as a park near the more then one million City Sofia – capital of Bulgaria. The mountain boundary reaches northward the Sofia field, westward to the Saddle Palakirska and southward borders on the Plain Samokov. Vitosha has 278 km2 area and is divided into four main parts. The Eastern Vitosha is next to the Mountain Plana and in this part are situated some of the highest peaks – Big Rezen (2277) and Little Rezen (2191). Here is located and the natural Resort “Bistrishko Branishte” and ski Center “Aleko”. The Southwestern part is the biggest one touched by the Mountain Verila. In this part is the longest Bulgarian cave – “Duhlata”. The Northwestern part spreads to the Mountain Lulin with the spring of the biggest Vitosha river – Struma. The Northern Vitosha part is the most visited and urbanized one with many hotels, huts and other tourist objects. The mountain is a protected National park from 1934. The average monthly temperature for January is –8.3oC and 9oC for July. Here could be observed the phenomenon inversion - when Sofia is covered with cold and fog in the mountain is hot and sunny. This phenomenon happens 15 times per year. On the high peaks the winter lasts between 5 and 7 months, the summer only 2 months – July and August. The wettest month is July and the driest one is September. The snow cover is thickest in March. The specific climatic conditions are the main factor forming the water discharge characterized with spring maximum (Mai-July) and autumn minimum (September-October). The rivers taking their sources in Vitosha flow to the Black Sea through the Rivers Iskar and Danube and to the Aegean Sea through Struma. The watershed begins from the Vladaia passage and follows the peaks Ostretz, Black Peak and Kupena. The biggest river passing by the Vitosha is the River Iskar - main and natural water collector of the all region. Comparatively big rivers in the frame of the mountain are the Rivers Simeonovska, Dragalevska, Bojanska, Vladajska and Struma. There are several smaller ones, which are tributaries of the Rivers Iskar or Struma as Bistrishka, Jeleznishka, Palakaria, Matitza, Kladnitza and others. Water bodies protection and Ecohydrology 1 BALWOIS 2004 Ohrid, FY Republic of Macedonia, 25-29 May 2004 Figure 1. Scheme of the Rivers in the Vitosha Mountain The development and enlargement of the urbanized zones, house and industrial constriction and the new transport connections alter the ecological status of the surface and ground waters and impose the necessity of new serious investigations concerning Vitosha’ rivers conditions, their topographic situation, stability of river bed and banks, water quality. There are not natural lakes. The artificial – the Reservoir “Studena” and the Lake Bojana are linked with the Towns Sofia and Pernik for drinking water supply. From the geological point of view the Mountain Vitosha presents laccolith – syenite massif (the Mountain Vitosha pluton). An attitude exists that the Vitosha syeniormations are realized during Carboniferous period when the mountain represents a volcano. This volcano has renovated its activities during Late Cretaceous period when andesite masses have been created. Currently, it is considered that the Mountain Vitosha is constructed mainly from at an Early Paleogene age granitoid rocks: gabbro, monzonite, syenite and granosyenite – the youngest intrusive rocks in the country. The Southern slopes are constructed by different types of sedimentary rocks including a large variety geological ages and tectonic crackings. As significant groundwater collectors are the Triassic limestones and dolomites. Water quality of the Vitosha waters Surface water The water quality investigations in the Vitosha region are carried out sporadically comprising mainly the mineral content and oxygen regime. The present material summed up the results of expeditions for the last five years. The monitoring programme comprises sampling points on the fifth major water streams – Rivers Simeonovska, Dragalevska, Bojanska, Vladajska and Sruma. The scale of studied water quality parameters is enlarged and the parameters are united in four groups: parameters Water bodies protection and Ecohydrology 2 BALWOIS 2004 Ohrid, FY Republic of Macedonia, 25-29 May 2004 characterizing oxygen regime and organic pollution – dissolved oxygen (O2), BOD5, permanganate oxidation (Ox); parameters for the mineral content – hydrocarbonate (HCO3), sulfates (SO4), chlorides (Cl), calcium (Ca), magnesium (Mg), hardness (H); biogenic elements or nutrients – nitrate (NO3), nitrite (NO2), ammonium (NH4), phosphates (PO4); and pH of waters. On the Table 1 are presented the average values for the mentioned water quality parameters. Analysis of the results shows that the content of dissolved oxygen in the water is high (average values from 8.1 to 11.5 mg/l), as a result mainly of the aeration processes in the steep mountain streams. The measured values guarantee the conservation and normal development of the ecosystems. The low values of BOD5 and permanganate oxidation, as generalized parameters show that there are not significant organic pollution in the waters (Table 1). The obtained values are normal for the natural development of biological processes. The inflowing organic pollution from different tourist objects obviously is small with dangerous impact on the water quality. Considering the mineral content, the Vitosha mountain can be assessed as hydrocarbonate-sulphate-calcium type of water. The hydrocarbonate anions and calcium cations prevail (Table 1). But the general mineral content of the all-fifth rivers is low and the waters are slightly mineralized. The measurements show the content of nutrients is low (Table 1) that means the local wastewater inflows are with small quantity without any significant influence over the water quality and resulting changes. The waters are mild (hardness between 0.7-2.1 oH), neutral or very slightly acid (average values for the different rivers are as follow: pH=7.1 for Simeonovska, pH=7.2 for Dragalevska, pH=6.8 for bojanska, pH=7.0 for Vladajska and pH=7.1 for Struma). Table 1. Water Quality Parameters of the Main Mountain Vitosha’ Rivers-Average Values in the Most Upper Streams in the Frame of the Mountain River O2 BOD5 oxidation HCO3 SO4 Cl Ca mg/l mg/l mg/l mg/l mg/l mg/l mg/l Simeonovska 11.2 2.0 2.1 37.4 8.4 6.2 11.1 Dragalevska 10.9 2.7 2.9 15.0 3.2 3.2 5.6 Bojanska 10.8 3.5 3.8 14.0 4.1 3.4 5.2 Vladaiska 11.5 2.4 2.9 24.5 15.4 5.5 9.9 Struma 8.1 3.4 3.6 67.1 28.8 6.4 18.4 River Mg total Fe NO3 NO2 PO4 NH4 Hardness mg/l mg/l mg/l mg/l mg/l mg/l oH Simeonovska 0.4 0.11 0.31 0.002 0.07 0.02 1.5 Dragalevska 0.4 0.09 0.22 0.001 0.02 0.00 0.7 Bojanska 0.2 0.07 0.22 0.001 0.01 0.04 0.7 Vladaiska 0.3 0.10 0.18 0.000 0.02 0.00 1.4 Struma 6.8 0.12 0.37 0.009 0.03 0.02 2.1 The presented above assessment reveals a still good conservation of water quality in the Vitosha’ rivers. Regarding the used water quality parameters the river waters have drinking quality. Vodenska (2002). Obviously the processes of urbanization are limited without big negative environmental impacts. The obtained results confirm the character of the rivers water quality close to the background conditions, especially in the upper parts. Tzankov et al (2001). Groundwater quality The fractured zone created by intrusion and evaluation of the Vitosha pluton, possesses a character like a ring, contributes fresh thermal groundwater discharge to the Villages Kniagevo, Rudarci and Pancharevo. The Vitosha pluton together with the other massifs around the City Sofia are the main Water bodies protection and Ecohydrology 3 BALWOIS 2004 Ohrid, FY Republic of Macedonia, 25-29 May 2004 source of groundwater recharge and bearing pressure over the Sofia water joint system.