National authorities very often will require the responsible party to secure permits for dredging operations in accordance with international conventions (see
, Annex A, IADC/CEDA, 2008). If this is the case, the requirement should be identified during the planning stages and complied with prior to the start of dredging operations. They are usually obtained by the project owner.
Permits for dredging operations usually fall into several categories:
- planning permits,
- environmental impact assessments or statements,
- placement permits and
- materials mining permits.
Planning permits are obtained from the relevant authority and would normally be applied for by the owner/employer at the conceptual stage of the project. The relevant competent authority would take into account considerations such as:
- the overall effect on the country or community,
- possible detrimental environmental effects,
- possible alterations to the existing regime and
- the effect of alterations on neighbouring sites.
Environmental impact assessment
Within the European Union, the United States and many other countries, an environmental impact assessment
is mandatory prior to granting approval for most capital projects. Also, various bodies such as wildlife and nature conservancy bodies must be consulted and, in many cases, public enquiries must be held.
Placement permits are usually required in the industrialised world in order to place dredged materials at sea or on shore. These are international treaties and all countries who are signatory to such treaties are bound by these restrictions, although developing countries may have the intention, but frequently do not have the organisation or the financial backing, to enforce the proper licensing of placement areas.
In order to specify the permitted location for placement, the licensing authority would, in the case of sea placement, generally consider factors such as:
- water depth,
- volumes of material for disposed,
- nature of the material,
- the degree of contamination, if any, and
- the local ecology of the receiving environment including fishing.
Full particulars of the vessels engaged in placement would be required with regular returns being made to indicate:
- the quantity placed,
- the nature of the material, and
- the source.
Shore placement is regulated in a similar manner to sea placement, and generally samples from the proposed dredging location are required to be chemically analysed prior to permission being granted. Many countries have statutory bodies monitoring and/or licensing dredging and placement projects to ensure there are no detrimental effects on sea defences, safety and navigational depths and that projects have no adverse environmental impact.
It is worth noting that, at the time of the initial site investigation to establish the
dredgeability of the material and the economic viability of the scheme, suitable representative samples should be collected. They should be stored for use and analysis when the time comes for applying for placement permission.
Particular care should be taken regarding the storage and preservation of samples to ensure in situ conditions are maintained insofar as is possible.
As environmental consciousness is increasing worldwide, regulations pertaining to the relocation of unusable materials are becoming far more stringent. That said, it is good to bear in mind that most dredged material is usable.
Materials mining permits
Many countries regulate the winning of reclamation and/or construction materials from rivers or the seabed. Frequently, the licensing authority will require payment of a royalty before permission is granted to remove materials such as sand and gravel from the seabed.