Activity 3.3 Floodplain assessment on selected tributaries Yantra River Bulgaria D 3.3.2 - List of floodplains, their characteristics, restoration/preservation potential and associated measures D 3.3.3. - Recommendations for floodplain assessment on tributaries including the description of implemented methods and classification criteria. Report Part 2 – Results April, 2020 TABLE OF CONTENTS INTRODUCTION 4 IDENTIFICATION OF FLOODPLAINS ALONG OF THE YANTRA RIVER 5 PRELIMINARY ASSESSMENT OF ACTIVE AND POTENTIAL FLOODPLAINS ALONG THE MAIN COURSE OF YANTRA RIVER 6 REFINING THE BOUNDARIES OF THE ACTIVE AND POTENTIAL FLOODPLAINS ALONG THE MAIN COURSE OF THE YANTRA RIVER 9 CLASSIFICATION OF FLOODPLAINS ACCORDING TO THEIR SIZE 9 EVALUATION OF THE EFFICIENCY OF FLOODPLAINS ALONG THE YANTRA RIVER 13 HYDROLOGICAL AND HYDRAULIC PARAMETERS 13 HYDROGRAPHS ON FLOODPLAINS 15 RESULTS OF THE EVALUATION OF THE EFFECTIVENESS OF FLOODPLAINS BY HYDROLOGICAL PARAMETERS 26 RESULTS OF THE EVALUATION OF THE EFFECTIVENESS OF FLOODPLAINS BY HYDRAULIC PARAMETERS 28 ECOLOGICAL PARAMETERS 29 RESULTS OF THE EVALUATION OF THE EFFECTIVENESS OF FLOODPLAINS BY ECOLOGICAL PARAMETERS 29 SOCIO-ECONOMIC PARAMETERS 32 RESULTS OF THE EVALUATION OF THE EFFECTIVENESS OF FLOODPLAINS BY SOCIO-ECONOMIC PARAMETERS 32 ADDITIONAL EVALUATION RESULTS 33 Page 2 of 36 LIST OF FIGURES: FIGURE 1: GEOGRAPHICAL MAP OF THE YANTRA RIVER CATCHMENT AREA _____________________________ 5 FIGURE 2: MAIN COURSE OF THE YANTRA RIVER ___________________________________________________ 6 FIGURE 3: COMPUTING NETWORK ______________________________________________________________ 8 FIGURE 4: COMPUTING NETWORK BASED ON DIGITAL ELEVATION MODEL WITH DYKES AND RIVERBED ______ 8 FIGURE 5: MAP SHOWING THE POSITION OF THE FLOODPLAINS ALONG THE YANTRA RIVER MAIN COURSE - UPPER, MIDDLE AND LOWER. _____________________________________________________________ 12 FIGURE 6: MAP OF LAND COVER / LAND USE TYPES _______________________________________________ 13 FIGURE 7: HIGH WAVE HYDROGRAPH USED IN THE COMPUTATIONAL MODEL _________________________ 14 FIGURE 8: FLOOD EXTENT, FLOOD DEPTHS, FLOW VELOCITIES _______________________________________ 15 FIGURE 9: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_001 __________________________________ 16 FIGURE 10: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_002 _________________________________ 16 FIGURE 11: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_003 _________________________________ 17 FIGURE 12: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_004 _________________________________ 17 FIGURE 13: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_005 _________________________________ 18 FIGURE 14: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_006 _________________________________ 18 FIGURE 15: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_007 _________________________________ 19 FIGURE 16: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_008 _________________________________ 19 FIGURE 17: HYDROGRAPH OF ACTIVE FLOODPLAIN BG_YN_AFP_009 _________________________________ 20 FIGURE 18: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_001 ______________________________ 20 FIGURE 19: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_002 ______________________________ 21 FIGURE 20: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_003 ______________________________ 21 FIGURE 21: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_004 ______________________________ 22 FIGURE 22: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_005 ______________________________ 22 FIGURE 23: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_006 ______________________________ 23 FIGURE 24: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_007 ______________________________ 23 FIGURE 25: HYDROGRAPH OF POTENTIAL FLOODPLAIN BG_YN_PFP_008 ______________________________ 24 FIGURE 26: OLD AND CURRENT RIVER BED OF THE YANTRA RIVER IN THE SECTION BETWEEN POLSKO KOSSOVO VILLAGE AND BYALA STATION _____________________________________________________________ 25 LIST OF TABLES: TABLE 1: LIST OF FLOODPLAINS ALONG THE MAIN COURSE OF THE YANTRA RIVER _______________________ 9 TABLE 2: EVALUATION OF FLOODPLAINS IN THE MAIN COURSE OF THE YANTRA RIVER BY HYDROLOGICAL PARAMETERS __________________________________________________________________________ 26 TABLE 3: EVALUATION OF FLOODPLAINS IN THE MAIN COURSE OF THE YANTRA RIVER BY HYDRAULIC PARAMETERS __________________________________________________________________________ 28 TABLE 4: EVALUATION OF FLOODPLAINS IN THE MAIN COURSE OF THE YANTRA RIVER BY ECOLOGICAL PARAMETERS __________________________________________________________________________ 30 TABLE 5: EVALUATION OF FLOODPLAINS IN THE MAIN COURSE OF THE YANTRA RIVER BY SOCIO-ECONOMIC PARAMETERS __________________________________________________________________________ 32 TABLE 6: EVALUATION OF THE FLOODPLAINS ON YANTRA RIVER BY PARAMETERS IN 3-LEVEL SCALE _______ 34 Page 3 of 36 INTRODUCTION The Danube Floodplain project is aimed to improving transnational water management, providing an approach for coordination of measures to reduce flood risk without conflicting WFD. The floodplains are important tool for flood risk reduction while maximizing benefits for biodiversity conservation and thus contributing to the achievement of the goals of both Floods Directive and WFD. The identification of existing and potentially restorable floodplains and the assessment of their efficiency is a precondition for their restoration and preservation, so under the project, an approach for floodplains delineation and assessment was agreed and applied. The analytical approach is based on the Floodplain Evaluation Matrix (FEM), which defines the main evaluation criteria, organised in four main groups - hydrological, hydraulic, environmental and socio-economic. Besides the floodplains on the Danube, the project activities include also assessment of floodplains on selected Danube tributaries. The assessemnt of the floodplains on the tributaries is using the concept and FEM, applied for the Danube River, considering the specifics of the selected river and national conditions. The activities on delineatieon and assessment of the floodplains on the BG Danube tribytary – Yantra river were contracted as external service and were performed by the team of Bulgarian company “Geopolymorphic Ltd”. This document presents the results of the identification and evaluation of the floodplains along the main river course of Yantra River. The methodology used is based on the methodology and FEM concept, agreed under the project, and further developed according to the river characteristics and the national conditions and data. The methodology is presented in a separate document (Part 1 of the Report). The methodology for identification of floodplains is designed to delineate two main types of floodplains - active and potential. The active floodplains are those which have a hydraulic connection to the main river channel and the extent of the flooded area depends on the water quantity and the land forms. In the case of hydrotechnical facilities, for example dikes, the border of the active floodplain is limited by them. Potential floodplains include hydrotechnical structures that limit river overflow. In the past, before the construction of these facilities, they have functioned as active floodplains. An evaluation of the effectiveness of floodplains (active and potential) is made with a view to taking future action to preserve and / or restore them. The methodology created for this purpose involves the survey of floodplains in various aspects, which can be divided into four main groups - hydrological, hydraulic, ecological and socio-economic. Each group includes a number of parameters that are selected so that they can be calculated with accessible, open and nation-wide data. Both methodologies are applied for the identification and evaluation of all floodplains along the main course of the Yantra River. The floodplains along this course are distinguished by a great variety in terms of their land forms on the one hand and their urbanization on the other. The purpose of considering all floodplains is to investigate a larger set of conditions for the formation of floodplains in Bulgaria. Page 4 of 36 Identification of Floodplains along of the Yantra River The methodology for identification of active and potential floodplains will be applied to the main course of the Yantra River. The Yantra River is 223.5 km long and has a catchment area of 7 862 km2. The river originates from the Shipka part of the Balkan, east of Hadji Dimitar (Buzludzha) Peak 1439.8 m. It crosses the Predbalkan and the Danube Plains and flows into the Danube River near the village of Krivina (Russe), east of Vardim Island. The catchment area of the Yantra River is fan-shaped - with an extended southern part and a narrowed northern one. The river receives three large tributaries, whose catchment area is equal to nearly 70% of the total catchment area of the Yantra River - Rositsa River (left tributary - 28.6%), Belitsa River (right tributary - 9.4%) and the Lefedzha River (30.9%). Figure 1: Geographical map of the Yantra River catchment area This study identifies floodplains along the main Yantra River course. Due to the relatively identical way of determining the active and potential floodplains, they were considered together. Page 5 of 36 Preliminary assessment of active and potential floodplains along the main course of Yantra River 1. Defining the study area In this step, the territory with a direct outflow to the Yantra River is defined. According