Hamburg Port Authority (HPA) and Federal Waterways and Shipping Administration (WSA) River Elbe River Engineering and Sediment Management Concept Review of sediment management strategy in the context of other European estuaries from a morphological perspective Report R.1805 May 2011 River Elbe River Engineering and Sediment Management Concept Review of sediment management strategy in the context of other European estuaries from a morphological perspective Summary The purpose of the current project is for six international experts to analyse and evaluate the proposed River Engineering and Sediment Management Concept (RESMC) for the River Elbe, particularly with respect to the individual groups of measures proposed and the likelihood for success, taking account of compatibility with the objective of sustainable development on the tidal Elbe. Peter whitehead of ABP Marine Environmental Research Ltd (ABPmer) in the UK has been commissioned to: "evaluate the RESMC in view of sediment management strategies in other European estuaries from a morphological perspective”. During the last decade considerable change has occurred in the siltation patterns of the River Elbe. This has generally required more maintenance dredging to take place in the channels near to the mouth and particularly in the Port of Hamburg area with less between these two areas. In the port area the maintenance dredge commitment has increased from around 2 million m3 in 2000 to over 8 million m3 in 2004/5. This additional material from down estuary mixes with the contaminated sediments from up-river, creating a larger volume of material with a significant contaminant content to be managed at considerable additional cost. This has led to increased practical problems in maintaining navigation whilst needing to comply with European nature conservation and water quality legislation. Discussions with the Lander of Hamburg, Lower Saxony and Schleswig Holstein, and agreement between the Hamburg Port Authority and the Federal Waterways and Shipping Administration (WSA) who are responsible for maintaining navigation of the Elbe Waterway, led to the development of the RESMC, published in 2008 (HPA & WSD-N (2008). The concept is based on a holistic understanding of the estuary dynamics as whole and promotes measures for sustainable management of the tidal Elbe and Port of Hamburg for the future. The main goals of the RESMC strategy are to reduce the maintenance dredging, reduce HW levels in the estuary thus reducing flood risk, increasing Low Water (LW) levels thus aiding navigation, and reducing contamination within the estuary in a sustainable manner whilst complying with national and international legislation. This report provides an overview of the understanding of the historical development of the River Elbe, before the start of the implementation of the RESMC measures, and provides a discussion of the influence of various 'modifications’ on the morphology, processes and sedimentary regime of the estuary. This is followed by a review of the various measures proposed in the RESMC, indicating their likely effectiveness in the ‘light' of the previous historical understanding and the current processes at work in the estuary. In order to satisfy the project scope, the RESMC has been evaluated against various sediment management strategies and practices that have been implemented across a range of European estuaries, which include Southampton Water, Medina, Humber and Mersey Estuaries in the UK and the Western Scheldt. R/3984/1 (i) R.1805 River Elbe River Engineering and Sediment Management Concept Review of sediment management strategy in the context of other European estuaries from a morphological perspective Acknowledgements In undertaking this review and preparing this report thanks are expressed to the advisory body and project office for the River Elbe River Engineering and Sediment Management Concept, comprising: . Svenja Beilfuss - BIOCONSULT Schuchardt & Scholle GbR; . Günther Eichweber - Wasser- und Schifffahrtsdirektion Nord (WSD); . Ingo Entelmann - Wasser- und Schifffahrtsamt Hamburg (WSA); . Peter Heininger - Bundesanstalt für Gewässerkunde; . Nicole von Lieberman - Hamburg Port Authority AöR (HPA); . Axel Netzband - Hamburg Port Authority AöR (HPA); . Klaus Rickert-Niebuhr - Wasser- und Schifffahrtsdirektion Nord (WSD); . Henrich Röper - Hamburg Port Authority AöR (HPA); . Bastian Schuchardt - BIOCONSULT Schuchardt & Scholle GbR; and . Holger Weilbeer - Bundesanstalt für Wasserbau (BAW). R/3984/1 (ii) R.1805 River Elbe River Engineering and Sediment Management Concept Review of sediment management strategy in the context of other European estuaries from a morphological perspective River Elbe River Engineering and Sediment Management Concept Review of sediment management strategy in the context of other European estuaries from a morphological perspective Contents Page Summary ..................................................................................................................................................i Acknowledgements.................................................................................................................................. ii 1. Introduction.................................................................................................................................1 1.1 General Historical Background...................................................................................................1 1.1.1 Port Development ........................................................................................................1 1.1.2 Flood Risk ....................................................................................................................1 1.1.3 Coastal Squeeze..........................................................................................................1 1.1.4 Hamburg and the Tidal Elbe.........................................................................................2 1.1.5 Present Project.............................................................................................................3 2. Report Structure .........................................................................................................................3 3. River Elbe Sediment Management Concept...............................................................................4 4. Package Review Objective.........................................................................................................6 5. Method .......................................................................................................................................7 6. Objective Analysis ......................................................................................................................8 6.1 Understanding of the Historical Development on the Morphology and Dynamics of the River Elbe...................................................................................................................................8 6.1.1 Morphology ..................................................................................................................8 6.1.2 Dredging.....................................................................................................................11 6.1.3 Constructions .............................................................................................................20 6.2 Conceptual Understanding of Estuary Processes ....................................................................25 6.2.1 Morphological Change ...............................................................................................25 6.2.2 Tidal Propagation.......................................................................................................25 6.2.3 Salinity........................................................................................................................27 6.2.4 Headwater Discharge.................................................................................................27 6.2.5 Sediments ..................................................................................................................28 6.2.6 Flow Speeds and Sediment Dynamics.......................................................................29 6.3 Scope of RESMC Strategy.......................................................................................................31 6.3.1 River Engineering Measures......................................................................................31 6.3.2 Dredge Methodology..................................................................................................35 R/3984/1 (iii) R.1805 River Elbe River Engineering and Sediment Management Concept Review of sediment management strategy in the context of other European estuaries from a morphological perspective 7. Management Strategies used in Europe...................................................................................38 7.1 Benefits of Large Scale Managed Realignment in the UK........................................................39 7.1.1 Flood Risk Reduction.................................................................................................40 7.1.2 Managed Realignment to Remove Sediment.............................................................41 7.1.3 Overview ....................................................................................................................42 7.2 Southampton Water..................................................................................................................42