In December 2010 Great Lakes Council received a Pindimar and Bundabah Foreshore Erosion Study which included the following Foreshore Management Guidelines which are as applicable to the North Arm Cove village as they are to Bundabah and Pindimar.
On natural shorelines, there are natural cycles of erosion during storms followed by accretion during good weather. The erosion events do not necessarily mean that the shoreline is receding over the long term. On natural shorelines, ‘hard’ structures hinder sediment building up on the shoreline during good weather, and this means there is no buffer for erosion during storms. The measures below help the shoreline build up sand naturally.
- Plant native shrubs, trees and ground cover on your foreshore edge, which will help capture sediment and build the shoreline. Some good plants include Swamp Oak (Casuarina glauca), Coastal Wattle (Acacia longifolia subsp. sophorae) and Coastal Banksia (Banksia integrifolia). Refer to Council’s website for more local species.
- Don’t place waste such as bricks, concrete or rubble on the shoreline. It is a danger to the public accessing the foreshore, it is unsightly, and it is damaging to the environment.
- Remove any ‘hard’ materials placed on the foreshore, such as bricks, rubble, rocks, or concrete.
- After removing materials, stabilise the foreshore by replanting with native ground cover, shrubs, trees.
- Do not build structures such as walls, groynes, steps or ramps on the foreshore. All of these structures constrict the movement of water and sand, causing erosion around the structure.
- Don’t damage or remove foreshore plants especially mangroves, mangrove seedlings or saltmarsh. Works on the foreshore require development consent from Council. You should consult with Council regarding the legislation governing the foreshore and adjacent marine park before undertaking works on the foreshore.
Many locals will know the effort required to maintain vertical walls, and this is because the walls are directly impacted by waves and currents, instead of reducing this energy. You can improve the performance of your existing structures to reduce erosion and improve the habitat for fish and shorebirds, as follows.
- Place rock (armour stone) in front of the vertical wall to produce a gentle slope (1:4), ensuring that the rocks are of a sufficient size to withstand the wave energy (see diagram).
- Place the rocks to give variations in slope and crevices
- Encourage mangrove seedlings to grow in gaps between the rocks at the toe of the seawall
- Plant native shrubs, trees and ground cover on your foreshore behind the seawall, for example, ‘Coastal Pigface’ (Carpobrotus glaucescens), Coastal Wattle (Acacia longifolia subsp. sophorae) and Coastal Banksia (Banksia integrifolia). Refer to Council’s website for more local species.
- Don’t place waste such as bricks, concrete or wood on the shoreline or as part of any structure. It is a danger to the public accessing the foreshore, it is unsightly, and it is damaging to the environment.
- Don’t damage or remove foreshore plants especially mangroves, mangrove seedlings or saltmarsh.
- Do ensure your existing structure has a geotextile fabric so that backfill does not erode from behind the structure.
- Do ensure your existing structure allows drainage for water to escape from behind the wall. Without drainage, land behind the wall can become saturated and cause the wall to collapse.
- Don’t construct groynes as part of any structure. All structural works on the foreshore require development consent from Council. You should consult with Council regarding the legislation governing the foreshore and adjacent marine park before undertaking works on the foreshore.
These guidelines were prepared by:
for Great Lakes Council.
