7 Foreshore and/or Seabed Disturbances

This chapter deals with activities which disturb the foreshore and/or seabed, such as reclamations, sand extraction, and the dredging and disposal of material.

Section 12(1)(c) and (e) of the RMA state that no person may, in the CMA, destroy, damage or disturb the foreshore or seabed in a manner that is likely to have an adverse effect on the foreshore or seabed, or on plants and animals or their habitats, unless expressly allowed by a rule in a regional coastal plan or a resource consent. In addition, s12(1)(a) and s12(2)(b) similarly restrict reclamation and drainage of the foreshore and seabed, and the removal of sand, shell, shingle or other natural material respectively.

There are many activities carried out in the CMA which enhance amenity values, alleviate problems which threaten public safety or well-being, and improve public access, but which also disturb the foreshore and seabed. Such activities may include beach grooming, the removal of vegetation, the use of vehicles on the foreshore, and the burial of dead marine mammals and other marine fauna. These activities also have potential adverse effects including the degradation of natural character, modification of coastal processes, damage or destruction of habitat, and temporary adverse effects on water quality.

Many of these activities are carried out both above and below Mean High Water Springs and therefore require a co-ordinated approach between Environment Waikato and territorial authorities.

Reclamation and drainage have, in the past, been seen as enhancing the economic and social well-being of the community by increasing the area of useable land, or by enhancing access to the coast. However, reclamations also have adverse effects which, in most instances, are irreversible. The adverse effects of reclamation and drainage include loss of coastal habitats and ecosystems, degradation or loss of natural character, changes in current patterns and sedimentation processes, loss of public access to that part of the CMA, and adverse effects on heritage resources.

Declamations are another form of disturbance to the foreshore and seabed which require co-ordinated management between regional and territorial authorities. The adverse effects associated with this type of activity are similar to those of reclamations, especially with respect to habitat and ecosystem destruction and land instability.

Dredging is required for the development and maintenance of operations such as marinas, wharves, jetties and navigational channels. Dredging facilitates the continued operation of these activities which contribute to the social and economic well-being, health and safety of the community. However, adverse effects associated with dredging include the potential to cause or exacerbate coastal erosion, the disturbance and destruction of habitats, the smothering of benthic communities by sedimentation, and impacts on spiritual values, amenity values and recreational use.

Extraction of material from the CMA is another form of disturbance with effects similar to those of dredging. It is likely that demand for mineral resources will increase in the future.

The disposal of dredged material, whether inside or outside of the CMA, is necessary following dredging of the CMA. There may also be instances where deposition of material from outside the CMA is required, for example, for the purpose of beach nourishment. Disposal or deposition can have adverse effects on coastal processes, water quality, sediment quality and ecology, and effectively smothers a portion of the seabed along with its associated flora and fauna. Longer term impacts can also occur as sediment becomes re-suspended or as contaminants are leached into the water. These contaminants may have significant adverse effects on biota if present in toxic concentrations and, longer term, more widespread effects can occur if they become bio-accumulated through the food chain.