Towards Practical Guidance for Sustainable Sediment Management using the Sava River Basin as a Showcase Estimation of Sediment Balance for the Sava River December 2013 UNESCO ISRBC SedNet Prepared by: International Sava River Basin Commission (ISRBC) in cooperation with the Core expert group from the Parties to the Framework Agreement on the Sava River Basin: Dr. Marina Babić-Mladenović Institute for the Development of Water Resources „Jaroslav Černi“ (Belgrade- RS) Dr. Damir Bekić University of Zagreb, Faculty of Civil Engineering (Zagreb- HR) Samo Grošelj International Sava River Basin Commission Dr. Tarik Kupusović Hydro-Engineering Institute of Civil Engineering Faculty (Sarajevo-BA) Dr. Matjaž Mikoš Faculty of Civil and Geodetic Engineering, University of Ljubljana (Ljubljana-SI) Dijana Oskoruš Meteorological and Hydrological Service of the Republic of Croatia (Zagreb-HR) And additional experts: Vanja Damjanović Institute for the Development of Water Resources „Jaroslav Černi“ (Belgrade- RS) Dragana Ninković Institute for the Development of Water Resources „Jaroslav Černi“ (Belgrade- RS) Dr. Radmila Milačič Institute Jožef Stefan (Ljubljana- SI) Dr. Slobodan Petković Institute for the Development of Water Resources „Jaroslav Černi“ (Belgrade- RS) Published by: International Sava River Basin Commission Kneza Branimira 29 Zagreb, Croatia Phone: + 385 1 488 6960 Fax: + 385 1 488 6986 E-mail: [email protected] Web: http://www.savacommission.org Supported by: UNESCO Office in Venice 4930 Palazzo Zorzi- Castelo Venice, Italy DELTARES (SedNet) PO Box 177 2600 MH Delft, Netherlands The Report is available at the website of the ISRBC BALSES UNESCO ISRBC SedNet BALSES UNESCO ISRBC SedNet CONTENTS 1. INTRODUCTION ..........................................................................................................................1 2. OVERVIEW OF THE SAVA RIVER BASIN AND ITS MAIN RIVERS ...................................................2 2.1. Main characteristics of the Sava River Basin ......................................................................... 2 2.1.1. Relief and topography .............................................................................................. 2 2.1.2. Hydrography ............................................................................................................. 3 2.1.3. Geology and hydrogeology ....................................................................................... 4 2.1.4. Land cover ................................................................................................................. 5 2.1.5. Climate ...................................................................................................................... 6 2.1.6. Precipitation and runoff ............................................................................................ 6 2.2. Main characteristics of the Sava River main course .............................................................. 8 2.2.1. Specific sections ........................................................................................................ 8 2.2.2. Longitudinal profile ................................................................................................... 8 2.2.3. Bottom sediment ...................................................................................................... 9 2.2.4. Dams and hydropower plants................................................................................. 10 2.3. Main characteristics of the Sava River tributaries .............................................................. 10 2.3.1. Overview of Sava River tributaries ......................................................................... 10 2.3.2. Previous estimation of sediment yield and transport ............................................. 12 2.3.3. Dams and hydropower plants on the tributaries of the Sava River ........................ 13 2.3.4. Case study 1: The impact of the construction of HPP Mratinje on the sediment system in Foča ........................................................................................................ 13 2.3.5. Case study 2: Sedimentation of HPP Zvornik and its influence on fluvial processes on the downstream Drina River section (Lower Drina) .......................................... 16 2.3.6. Case Study 3: Sediment Quantity in the reservoir Modrac .................................... 17 3. SEDIMENT MONITORING AND ASSESSMENT ............................................................................ 19 3.1. Methodologies .................................................................................................................... 19 3.1.1. Suspended sediment measurements ...................................................................... 19 3.1.2. Bedload measurements .......................................................................................... 19 3.1.3. Monitoring of the river channel evolution .............................................................. 20 3.1.4. Sediment quality monitoring .................................................................................. 21 3.1.5. Soil erosion surveys ................................................................................................. 22 3.1.6. Reservoir sedimentation measurements ................................................................ 23 3.2. Actual monitoring in the Sava River Basin countries .......................................................... 23 3.2.1. Overview of the sediment monitoring in Sava River Basin ..................................... 23 3.2.2. Slovenia ................................................................................................................... 24 3.2.3. Croatia .................................................................................................................... 25 3.2.4. Bosnia and Herzegovina ......................................................................................... 28 3.2.5. Serbia ...................................................................................................................... 30 3.3. Elements and persisting pollutants in sediments of the Sava River ................................... 31 3.4. Concluding remarks on the actual monitoring in the Sava River Basin countries .............. 34 4. SAVA RIVER CHANNEL EVOLUTION IN TIME ............................................................................. 36 4.1. General remarks .................................................................................................................. 36 BALSES UNESCO ISRBC SedNet 4.2. The case study of the Sava River channel bed changes in the Ljubljanska Sava River reach, Slovenia ............................................................................................................................... 37 4.2.1. The history of river engineering works in the Ljubljanska Sava River ..................... 37 4.2.2. The longitudinal profile ........................................................................................... 42 4.3. The case study of the Sava River channel bed changes in the reach along the Nuclear Power Plant Krško, Slovenia ................................................................................................ 43 4.4. Riverbed measurements in the Lower Sava River in Slovenia ............................................ 45 4.5. The case study of the Sava River channel bed changes in the reach through the City of Zagreb, Croatia .................................................................................................................... 46 4.5.1. Introduction ............................................................................................................ 46 4.5.2. Stability of bridges .................................................................................................. 48 4.5.3. Flood protection scheme for the City of Zagreb ..................................................... 50 4.6. The case study of the Sava River channel bed changes in the reach upstream of the City of Belgrade, Serbia ................................................................................................................... 50 5. ESTIMATION OF THE SAVA RIVER SEDIMENT BALANCE ............................................................ 52 5.1. Introductory remarks .......................................................................................................... 52 5.2. Modes of sediment transport ............................................................................................. 52 5.3. Suspended sediment balance along the Sava River ............................................................ 53 5.3.1. Annual quantities of suspended sediments ............................................................ 53 5.3.2. Seasonal variability of suspended sediment transport ........................................... 62 5.3.3. Role of floods in suspended sediment transport .................................................... 64 5.4. Other components of sediment balance along the Sava River ........................................... 65 5.4.1. Bedload ................................................................................................................... 65 5.4.2. Fluvial erosion ......................................................................................................... 66 5.4.3. Dredging of sediments ...........................................................................................