Environmental Issues

The design and building of a new navigation channel or the modification of an existing channel have many strong relations to environmental issues, especially linked to dredging, blasting operations and maintenance dredging. These issues are strongly related to hydrological (tidal) effects, sedimentological impacts and effects on all biological chains.

Many PIANC reports deal with dredging and the environment and it is best to refer directly to those reports. Some examples include EnviCom WG 4 report – ‘Environmental Management Framework for Ports and Related Industries’ (1999), EnviCom WG 8 report – ‘Biological Assessment Guidance for Dredged Material’ (2006), EnviCom WG 10 report – ‘Environmental Risk Assessment of Dredging and Disposal Operations’ (2006), EnviCom WG 104 – ‘Dredging Material as a Resource’ (2009) and EnviCom WG 100 report – ‘Dredging Management Practices for the Environment – A Structured Selection Approach’ (2009).

4.5.1 Regulations and Sustainability

The maritime sector is by its very nature international and its functioning depends strongly on the international regulatory framework that has developed over the years. This regulatory framework is intended to provide a level playing field to maritime operators all over the world. The minimum standards provided in these regulations are an important driver for raising awareness and consideration of the different forms of environmental pressure that are associated with maritime activities.

The regulatory framework for sustainability issues in the maritime sector has become very complex and consists of a large number of regulations that have evolved with different forms of shipping. This basic framework is complemented, in some parts of the world, by additional national or international regulations.

For instance, the Environmental, Health and Safety (EHS) Guidelines issued by the IFC (International Finance Corporation) are technical reference documents with general and industry-specific examples of good international industry practice.

In all countries, there is an obligation to perform an ‘Environmental Impact Assessment’

(EIA) during planning of any type of important work. According to international legislation and especially the EU (European Union) Council Directive 85/337/EEC on the assessment of the effects of certain public and private projects on the environment, the environmental impact assessment shall identify, describe and assess in an appropriate manner, in the light of each individual case, the direct and indirect effects of a project on the following factors:

 Human beings, fauna and flora

 Soil, water, air, climate and the landscape

 Material assets and the cultural heritage

 Interaction between the factors mentioned above

The structure of an EIA is in all national and international legislations as follows:

 Define initial state of the environment at the site where the project will take place

 Complete analysis of all project impacts (temporary and permanent, direct and indirect)

 List reasons why the project was chosen, especially for environmental concern

 Describe mitigation measures considered to suppress, minimise and compensate the effect on environment and cost estimate of those measures

According to results of the EIA, mitigation of habitat losses through compensatory measures has long been applied when avoidance, minimisation and rectification of impacts were not feasible. Off-site restoration, enhancement and construction of wetlands and other habitats have been the most frequent compensations. The discussions around these compensatory measures are often very contentious among the stakeholders and can easily lead to long delays for some projects.

In 2008 PIANC proposed a new position paper to enable better environmental integration and social acceptance of projects called ‘Working with Nature’. Working with Nature is about more than avoiding or mitigating the environmental impacts of a pre-defined design. Rather, it sets out to identify ways of achieving the project objectives by working with natural processes to deliver environmental protection, restoration or enhancement outcomes.

Fundamentally, Working with Nature means doing things in a different order:

 Establish project need and objectives

 Understand the environment

 Make meaningful use of stakeholder engagement to identify possible win-win opportunities

 Prepare initial project proposals/design to benefit navigation and nature

Working with Nature thus requires a subtle but important evolution in the way project development is approached.

4.5.2 Work on Channels and Dredged Materials Management

Construction and maintenance dredging and dredged material disposal may impact habitats and pose a significant hazard to human health and the environment, particularly if the sediments are contaminated. As part of a Marine Dredging Management Plan, the following recommendations should be adopted to avoid, minimise, or control impacts from dredged materials.

4.5.2.1 Dredge Planning Activities

Dredging should only be conducted if necessary and based on an assessment of the real need for new infrastructure components or port navigation access to create or maintain safe navigations channels.

Prior to initiation of dredging activities, dredge materials should be evaluated for their physical, chemical, biological and engineering properties to determine their suitability for reuse or disposal options. This will be an important part of the EIA.

4.5.2.2 Dredging

Excavation and dredging methods should be selected to minimise suspension of sediments, minimise destruction of benthic habitat, increase the accuracy of the operation and maintain the density of the dredge material, especially if the dredge material includes contaminated materials.

Areas sensitive for marine life such as feeding, breeding, calving, and spawning areas should be identified. Where sensitive species are present, dredging (and blasting) should be conducted in a manner so as to avoid fish migration or spawning seasons, routes and grounds.

Use techniques (e.g. silt curtains) to minimise adverse impacts on aquatic life from the re-suspension of sediments.

Inspection and monitoring of dredging activities should be conducted to evaluate the effectiveness of impact prevention strategies and re-adjusted where necessary.

4.5.2.3 Disposal of Dredged Material

Dredged material should be analysed to select appropriate disposal options (e.g. land reclamation, open water discharge or contained disposal). Beneficial reuse of uncontaminated, dredged material should be considered as a use for compensatory

measures (e.g. for wetland creation or enhancements, habitat restoration, or creation of public access/recreational facilities).

Use of submerged discharges should be considered for hydraulic disposal of dredged material.

Use of lateral containment in open water disposal should be considered. Use of borrow pits or dykes reduces the spread of sediments and effects on benthic organisms.

Confined disposal facilities should be used, either near-shore or upland, when open water disposal is not feasible or desirable. If dredge material is contaminated, confined disposal facilities should include liners or other hydraulic containment design options to prevent leaching of contaminants into adjacent surface or groundwater bodies. Treatment of dewatering liquids (e.g. metals and persistent organic pollutants) may be required prior to discharge. Site-specific discharge quality standards should be established depending on the type and toxicity of the effluents and the discharge location.

4.5.3 Biodiversity

Construction and maintenance dredging; disposal of dredge material; construction of piers, wharves, breakwaters and other water-side structures; and erosion may lead to short and long-term impacts on aquatic and shoreline habitats. Direct impacts may include the physical removal or covering of sea floor, shore, or land-side habitat, in addition to changes to water flow patterns and related sedimentation rates and patterns.

Indirect impacts may result from changes to water quality from sediment suspension or discharges of storm water and wastewater.

Potential impacts to shoreline vegetation, wetlands, coral reefs, fisheries, bird life and other sensitive aquatic and near-shore habitats during port construction and operation should be fully assessed with special consideration for areas of high biodiversity or those required for the survival of critically endangered or endangered flora and fauna. The depth of the port should be considered in the design phase in terms of habitat destruction and the amount and nature of dredging required.

Additionally, specific prevention and mitigation measures should be adopted for blasting activities, which can cause considerable impacts to marine organisms and their habitats during construction.