Revitalization Options Danube Sidearm System Vizvar-Belavar
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CONCEPTUAL OVERVIEW OF THE REVITALIZATION OPTIONS FOR THE SIDE-ARM SYSTEM OF VÍZVÁR-BÉLAVÁR PROJECT PARTNER: Directorate of the Duna-Dráva National Park SUBCONTRACTOR: Inno-Water Research and Environmental Services Ltd. APRIL 2014, BUDAPEST Inno-Water Kutató és Környezetvédelmi Szolgáltató Ltd. Table of contents 1 Introduction and preliminaries ......................................................................................... 11 1.1 Introduction ............................................................................................................... 11 1.2 Tasks .......................................................................................................................... 12 2 Introduction to the area .................................................................................................... 14 2.1 General introduction to the area ................................................................................ 14 2.1.1 The location of the planning area ....................................................................... 14 2.1.2 Relief, geological and soil characteristics .......................................................... 14 2.1.3 Climate ............................................................................................................... 16 2.1.4 Characterization of the Hungarian Dráva stretch ............................................... 16 2.1.5 Flood control and protection .............................................................................. 21 2.1.6 Navigation .......................................................................................................... 22 2.1.7 Nature conservation ............................................................................................ 23 2.1.8 Ecosystem elements ........................................................................................... 25 2.2 Regulation of the Dráva River ................................................................................... 26 2.2.1 River regulation until 1886 ................................................................................ 26 2.2.2 River regulation from 1886 until World War I. ................................................. 29 2.2.3 River regulation between the two world wars and during the Second World War 31 2.2.4 River regulations from 1945 until the 1980‘s .................................................... 32 2.2.5 The results of the river regulation ...................................................................... 35 2.3 Presentation of the side-arm system of Vízvár-Bélavár and of the affected Drava section ................................................................................................................................... 37 2.3.1 The Lower side-arm of Vízvár ........................................................................... 38 2.3.2 The Upper side-arm of Vízvár ........................................................................... 38 2.3.3 The Side-arm of Bélavár .................................................................................... 39 2.3.4 Gravel-pit lakes of Bélavár ................................................................................ 41 2.3.5 Lower Drava (AEP438) water body ................................................................... 42 2.3.6 Land use on the planning area ............................................................................ 44 3 Principles of habitat revitalization .................................................................................... 46 3.1 Revitalization objectives as determined in watershed management plan .................. 48 Conceptual overview of the revitalization options for the side-arm system of Vízvár-Bélavár 2 Inno-Water Kutató és Környezetvédelmi Szolgáltató Ltd. 3.2 Baselines of the Vízvári-Bélavári side-arm system habitat revitalization conceptual plan 51 4 Options for habitat restoration on the basis of the international literature ....................... 53 4.1 Examples from Hungarian and foreign practice for revitalization of rivers with similar geographic characteristics ........................................................................................ 53 4.1.1 Revitalization of the oxbows of River Morava (Slovakia)................................. 53 4.1.2 River restoration and prevention of riverbed-erosion in the Danube Floodplain National Park (Austria) .................................................................................................... 57 4.1.3 Revitalization of the oxbows of the River Saône (France) ................................ 65 4.1.4 Revitalization of River Ain (France) .................................................................. 67 4.1.5 Proposals for the restoration of River Spree (Germany) based on the assessments of zoobenthos habitats. ................................................................................. 73 4.2 Options for managing channel deepening based on international experience ........... 76 5 Analysis of the Drava River water regime and alluvial flow on the project reach .......... 78 5.1 Statistical analysis of the Drava River water regime ................................................. 78 5.1.1 The methodology and objectives of the analysis ............................................... 78 5.1.2 The analysis of the water level and velocity data measured at Őrtilos river gauge 80 5.1.3 The analysis of the water level and velocity data measured at Vízvár-Heresznye river gauge ........................................................................................................................ 84 5.1.4 The analysis of the water level and velocity data measured at Barcs river gauge 86 5.2 Forecast of water level permanence of the Drava River ........................................... 90 5.2.1 The Drava River water levels extrapolation at the gauge of Őrtilos .................. 91 5.2.2 The Drava River water levels extrapolation at branch system of Vízvár-Bélavár 92 5.2.3 The Drava River water levels extrapolation at the gauge of Barcs .................... 93 5.3 Description of the sediment conditions on the Drava River ...................................... 94 5.3.1 Sediment volume based on regular measurements at the gauge of Barcs .......... 94 5.3.2 Sediment volume on the region of Bélavár ........................................................ 95 5.3.3 The rolling sediment samples grain composition at Bélavár ............................. 97 5.3.4 The suspended sediment samples grain composition at Bélavár ..................... 101 6 Observations and conclusions of the geodetic surveys and the site inspections ............ 105 Conceptual overview of the revitalization options for the side-arm system of Vízvár-Bélavár 3 Inno-Water Kutató és Környezetvédelmi Szolgáltató Ltd. 6.1 Location and time of the geodetic surveys .............................................................. 105 6.2 Geodetic survey results of the important channel alternatives in terms of the side- arm-system revitalization ................................................................................................... 107 6.2.1 Description of the 1st Channel alternative ........................................................ 108 6.2.2 Description of the 2nd Channel alternative ....................................................... 110 6.2.3 Description of the 3rd Channel alternative ........................................................ 112 6.2.4 Description of the 4th Channel alternative ........................................................ 113 6.2.5 Description of the 5th Channel alternative ........................................................ 115 6.2.6 Description of the 6th Channel alternative ........................................................ 118 6.2.7 Description of the 7th Channel alternative ........................................................ 119 7 Characterization of the state of natural water supply Vízvári-Bélavári branch system . 121 7.1 Methodology used ................................................................................................... 121 7.2 Analysis of the relation between the Drava water-levels and inflow levels at given frequency ............................................................................................................................ 122 7.3 The scientific investigation of the frequency of natural water recharges in 2009- 2013. 123 7.4 The analysis of the long-term changes in natural water recharge frequencies ........ 126 8 Managing the problem of riverbed deepening of the Drava .......................................... 131 8.1 Prevention of the channel deepening by adding coarse gravel ................................ 133 8.2 Prevention of riverbed deepening by slowing the river ........................................... 138 9 Review of the revitalization opportunities at the Vízvár-Bélavár side-arm system ....... 141 9.1 Implementation of the water supply by the local elevation of Drava water levels . 142 9.1.1 The impact of the water level elevation on the water recharge alternatives .... 144 9.2 Partial dredging of the channel line of water supply ............................................... 148 9.2.1 Effects of partial dredging to the water coverage of supply channels.............. 149 9.3 Simultaneous application of the dredging and water level increasing of the Drava 157 9.4 Summary of potential water supply alternatives and the proposed solution ........... 159 10