WG 128 : Alternative Technical-Biological Bank Protection Methods for Inland Waterways

Final stage

The PIANC INCOM WG 128 was established in 2009 but because of personnel problems the WG did not reach the objective.
Today it is planned to reactivate the working group. Because the knowledge on the design and maintenance of technical-biological bank protections has increased since 2009, e.g. there is a new German Guideline available, the former TOR will be updated as follows:

1 Background

Since the mid 1980’s, considerable interest has grown in the use of softer forms of bank protection to reduce costs, increase environmental benefits and more recently to demonstrate sustainable construction. In 1987 PIANC produced guidelines on the design and use of such techniques which were well-received and used to create industry standards.

In 2007, PIANC InCom WG27 reported that an increasing number of alternative bank protection measures are being implemented across the world in navigation channels, for example:

• Bio-engineering as reed planting or live willow fascine,
• Bio-technical engineering as grass composite, vegetated pocket fabric geo-textiles, rock and fibre rolls, planted coir pallets, and
• Structural engineering as timber revetments, wattle hurdles and timber piling.

However there is still limited published guidance based on actual experiences with existing alternative bank protection methods that identifies effective alternatives that can be used under specific project boundary conditions. Some of these documents were used in the WG27 report “Considerations to Reduce Environmental Impacts of Vessels” to select adequate mitigation measures. Further work has recently been undertaken by other PIANC Working Groups, namely MarCom 56 (Application of geo-textiles in waterfront protection) and CoCom 2 (Best practices for shoreline stabilization methods), to consider the use of geo-textiles in a coastal environment.

Whilst there is limited existing knowledge, there is an increasing pressure for those involved in channel design and maintenance to adopt new techniques on the assumption that these will better meet the following requirements:

• Engineering
• Ecological,
• Economic,

rather than the use of traditional engineering solutions such as riprap or sheet piling. Consequently there is a need for collecting and assessing existing experiences with alternative bank protection methods in a sense of a best practice approach to form a basis for an objective decision making tool for waterway improvement and management.

2 Objective

The objective of the new InCom WG128 is to understand, evaluate and report on the effectiveness of best practice examples of innovative (alternative) bank protection measures, as related to different impact influences and boundary conditions, to fulfil the technical purposes and additionally to improve the ecological conditions. To formulate recommendations based on results obtained from assessments of physically implemented schemes.

From the European perspective, the mandate of the Water Framework Directive and other initiatives has created a requirement for results that should be available as soon as possible. Therefore restrictions on the range and extent of the field of inquiry are necessary. To create an even more finite scope of activity by the working group, bank protection in lakes should be viewed as extraneous to the report.

Maintenance costs and details of ecological monitoring for selected alternatives must be available for a point in time at least one year after installation and must be included in the report.

Project details should include water body type (e.g., free flowing and dammed rivers, canals), climate, water level variation, flow velocity (both fast and slow), substrate of the banks, bank slope, distance to fairway, ship types and hydraulic impacts from shipping.

Information should be collected on successful and, to the fullest extent possible, on unsuccessful applications looking back over the last twenty years. It is felt that this is an appropriate timescale commensurate with the development of these techniques and will allow a full review to be undertaken to see how vegetative protection techniques have matured or not!

 

List of Members

Germany

Bernhard Söhngen (Chair)

Petra Fleischer

Christian Wolter

Hubert Liebenstein

USA

Kyle McKay

United Kingdom

Paul Wilkinson

Argentina

Gonzalo Duro

Belgium

Jeroen Verbelen

France

Christian Moiroud

 

 

Table of Contents

1 Introduction

1.1 Background (motivation for establishing the WG)

1.2 Terms of reference according to INCOM

1.3 Definition of technical-biological bank protections (all measures that help to improve bank stability and its ecological quality, measures both on the and in front of the bank)

1.4 Specifications of the terms of reference (no arid or permafrost regions)

1.5 Recommended approach (how to use the report; contribution of the report to the planning process, check whether TBP are necessary or not stays outside of the report)

2 Brief discussion on existing information

2.1 Focus 2.2 Guidelines (technical, biological, river restoration)

2.4 Relevant Literature

2.3 Case studies ("grey literature")

2.4 Summary of the literature survey (with the table discussed under TOP 3)

3 Synopsis (how to cope with the demand for improving ecology?)

3.1 Discussion of appropriate direct, indirect and flanking measures (e.g. ship speed limits)

3.1 Details of selected constructions and its potential ecological improvement

3.2 Construction and maintenance effort

4 Recommendations for choosing appropriate bank protections

4.1 Relevant local boundary conditions and data needed (waterway type, space available, necessary ecological improvement ...)

4.2 Choice and assessment of comprehensive "macroscopic" and "microscopic" design parameters

4.3 Brief discussion of the chosen measures in appendix 3 and the origin of the data provided

4.4 List of recommended measures with design-relevant properties (list with all properties, application limits, applicability indexes etc.)

4.5 Choice of appropriate measures in the sense of a best practice approach (decision making approach, relevant thresholds, applicability indexes, comparisons between actual and boundary and those in the list of recommended measures)

4.6 Reference to relevant codes of practice for a more detailed design