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Climate change and the increasing frequency of extreme rainfall events impose additional stress on urban drainage infrastructure and particularly on wastewater pumping stations operating within combined sewer systems. This study investigates the operational performance of an existing wastewater pumping station located in northeastern Bulgaria and subjected to significant hydraulic loading caused by permanent external inflows and stormwater runoff. The assessment combines field observations, SCADA-derived operation...

At present moment, Bulgarian regulatory documents lack rainfall hyetographs that can be used in computer models of sewer networks. In the conditions of climate change and the occurrence of extreme precipitation phenomena, this leads to difficulties in the application of sewer network modeling in solving engineering problems. It is not possible to perform a normatively defined determination of hydraulically overloaded sections of the sewer network, as well as to determine the expected frequency of flooding and floo...

The present article assesses the reliability of a water supply system that is fed by one of the large dams in Bulgaria and supplies water to three large settlements in the northeastern part of the country. The system consists of a water main with a length of about 25 km and three pumping stations. For each of the settlements that are supplied by this water supply system, the water has to be pumped by pumping stations to the pressure reservoirs. In recent years, the region has been experiencing significant drought,...

The design of urban drainage systems in the European Union generally follows the requirements of the EN 752 standard. Nevertheless, it uses a classical approach that aims only to convey stormwater runoff away from the settlement boundaries, thus preventing local problems. On the other hand, global tendencies are oriented towards a more sustainable approach for climate-adaptive metropolitan infrastructure. To address problems like urban expansion, expected future heavy rainfall events, sewer overloading, flooding, ...

In recent years the subject of reliability prediction of complex systems has become more significant because of increasing the criticality of the infrastructure. The present research refers to surveying the operation of pumping stations and problems encountered during the exploitation, as well as developing a reliability assessment methodology. The main causes of damages in pumping stations are analyzed according maintenance data from water supply and sewerage operators. Reliability assessment is based on the dete...