Groundwater contribution to the river flow for the upper course of the Osam River based on two baseflow separation methods

Pages: 
pp. 73-82
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 24, 1113 Sofia, Bulgaria
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 24, 1113 Sofia, Bulgaria
National Institute of Meteorology and Hydrology, 66 Tsarigradsko Shose Blvd, 1784 Sofia, Bulgaria
Abstract: 

The study area in the upper part of the Osam River basin (central North Bulgaria) is characterized by highly variable mountain relief and diversified geological and hydrogeological conditions. Mesozoic clayey-terrigenous sediments are widespread in the area. Triassic and Jurassic carbonate rocks are developed locally, mainly in the upper part of the river basin. The mountainous landscape is dominated by old-forest vegetation communities. Both fissured-porous and karst groundwater systems are developed in the area. The groundwater is recharged mostly from precipitation and forms baseflow of streams. The aim of the study is to evaluate the groundwater contribution to the river flow for the catchment area of the Cherni Osam River and the Beli Osam River, forming the upper course of the main Osam River. For this purpose, two baseflow separation methods are used (local minimum method and digital filter of Eckhardt). Daily data for the river stream gages for the period 2009–2015 were processed. The baseflow for the studied catchments shows higher value for the Cherni Osam River basin and almost twice as lower value for the Beli Osam River basin. These results are most probably largely related to both the karst area and the forest cover. The digital filter developed by Eckhardt is considered as the most reliable for baseflow separation for the study area.

Keywords: 

groundwater, baseflow separation, digital filter method, Osam River basin, Bulgaria

VOLUME 46 (2)/November 2017 125th Anniversary of Acad. Strashimir Dimitrov; 70th Anniversary of the Geological Institute, Bulgarian Academy of Sciences

University of Mining and Geology, Department of Geology and Geoinformatics, Studentski Grad, Prof. Boyan Kamenov Str., 1700 Sofia, Bulgaria; Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Ellatzite-Med PLC, 2086 Mirkovo, Sofia District, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia
|
Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute “Strashimir Dimitrov”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Department of Geology, Palaeontology and Fossil Fuels, Sofia University, 15 Tzar Osvoboditel Blvd, 1000 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warszawa, Poland
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Comenius University, Faculty of Natural Sciences, Department of Geology and Palaeontology, Mlynská dolina G–229, Ilkovičova 6, SK-84215 Bratislava, Slovak Republic
|
Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warszawa, Poland
|
Institute of Geology, Academy of Sciences of the Czech Republic, v.v.l., Rozvojová, 269,165 000 Praha 6, Czech Republic

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
University of Sofia “St Kliment Ohridski”, Faculty of History, Department of Archaeology, 15 Tsar Osvoboditel Blvd, 1000 Sofia, Bulgaria
| |
University of Sofia “St Kliment Ohridski”, Faculty of History, Department of Archaeology, 15 Tsar Osvoboditel Blvd, 1000 Sofia, Bulgaria
|
National Institute of Archaeology and Museum, Bulgarian Academy of Sciences, Department of Prehistory, 2 Saborna Str., 1000 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 24, 1113 Sofia, Bulgaria
|
National Institute of Meteorology and Hydrology, 66 Tsarigradsko Shose Blvd, 1784 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Faculty of Geology and Geography, Department of Geology, Palaeontology and Fossil Fuels, Sofia University “St Kliment Ohridski, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

University of Mining and Geology, Prof. B. Kamenov Str., Sofia, 1700. Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
|
University of Mining and Geology, Prof. B. Kamenov Str., Sofia, 1700. Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Austrian Institute of Technology, Center for Energy, Konrad-Lorenz-Str. 24, 3430 Tulln, Austria
|
Austrian Institute of Technology, Center for Energy, Konrad-Lorenz-Str. 24, 3430 Tulln, Austria
|
Austrian Institute of Technology, Center for Energy, Konrad-Lorenz-Str. 24, 3430 Tulln, Austria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria; Institute of Geochemistry and Petrology, ETH, 8092 Zurich, Switzerland
|
Institute of Geochemistry and Petrology, ETH, 8092 Zurich, Switzerland
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria