Sofia and reservoir monitoring in Dolni Okol village, Plana mountain



Sofia is the capital of Bulgaria and the centre of the Balkans region located between the Black Sea and the Adriatic Sea

Sofiyska Voda provides services within the territory of the state capital city of Sofia – economic and administrative center of Bulgaria – to more than 1.4 million people. Sofiyska Voda manages a water network that is mainly gravity driven. It has suffered from underinvestment the decade before the year of 2000. Potable water losses, together with a rehabilitation of the aging infrastructure and compliant water quality, have been the main focus of the concession and regulatory requirements. Sofiyska Voda, through its concession contract, has certain requirements for water security. At the moment the monitoring of water quality is aimed at tracking the parameters of potable water upon treatment, storage in reservoirs and in the water supply network. Currently, in the company there is no system for early warning and registration of the microbiological and / or physicochemical deviations from the water quality in the water sources.

SVK: Dolni Okol village is located in Plana Mountain, at 18 km from the town of Samokov. There are about 200 inhabitants living in the community, but during the summer time they amount to 500.


Water Supply and Sewerage Ltd.(SVK) operates a water pressure tank built in the village which is filled by a river catchment. This reservoir supplies the inhabitants of the community with drinking water. Prior to the water catchment, along the river a leather processing factory is operating. There is a high probability that chemicals such as Chromium, Sulfuric acid, colorings, etc. from this manufacturing works will come into the river to pollute the reservoir and the drinking water of the village. Every week samples are taken from the tank, but this is not enough to guarantee the quality of drinking water.

Actions and expected results


In the context of increased prevention, the early warning for pollutants and the presence of online monitors for microbiological and physicochemical indicators in the water sources and the reservoirs would lead to:


Considerable reduction of the time for taking reactive actions;

Timely resource mobilization in order to guarantee that the end customer will not be affected;

Enhanced emergency preparedness related to the safety of the potable water supplied to the end customer;

Measurement and tracking of quality indicators, for which there has been no data until now;

Accumulation of databases with quality indicators.


The information collected after the application of the project will be analysed in details and would be used to assess the risk of safe supply of potable water to an end customer; prepare an action plan with preventative measures in view of managing sudden wastewater discharges and optimize the processes for production of potable water-design water supply and sewerage infrastructure.

Lead partners