Four-fold approach taken to Ocean and Umina beaches
The Hawkesbury Nepean River System Coastal Management Program proposes a four-fold approach to maintaining Ocean and Umina Beaches.
The long-term strategy is to construct a dune-covered seawall, described as a "rock-armoured revetment" between Ocean Beach Surf Life Saving Club and the Kourung St boat ramp.
This is supported by a coastal vegetation and dune management strategy for the length of the beach, beach renourishment and a beach maintenance program.
The Umina-Ocean Beach Erosion Management Strategy would be implemented as the long-term plan for managing coastal erosion.
"It includes frequent monitoring of the beach and a trigger-based approach for construction of coastal protection works along 1300 meters of foreshore along The Esplanade.
"The strategy outlines a concept design for coastal protection, which features a rock-armoured revetment stretching from Kourung St boat ramp to Ocean Beach SLSC and a stepped concrete seawall in front of the Ocean Beach SLSC.
"Ongoing work would involve the development of a detailed design (including community engagement for local input and feedback), and future implementation based on erosion triggers."
According to the strategy completed in 2019, "the trigger for Council to call tenders for the construction of a rock revetment would be unsustainable dune maintenance and management (eg following one calendar year of little progress) in attempts to replenish and stabilise the dune following a severe storm or closely connected series of storms, leading to high and unacceptable risk to coastal infrastructure (eg stormwater outlets, footpaths, carparking areas, road pavements).
"The trigger for Council to commence construction of a rock revetment would be when the existing footpath is threatened by erosion (ie no dune buffer) for a continuous period of greater than three months.
"Threats to stormwater outlets should be manageable locally without the need to commit to a rock revetment.
"It should be noted that sectional installation of a rock revetment along vulnerable areas of the beach would need to consider potential 'end effects' at the extents of the structure.
"This could be mitigated by tying the structure into hard points (eg existing structures or natural features), positioning the end points away from at risk infrastructure or designing landward returns into areas of the natural dune system with a good sand buffer volume."
The supporting coastal vegetation and dune management strategy for Broken Bay beaches "would integrate with the Coastal Vegetation and Dune Management Strategy from the Open Coast Beaches CMP".
"It would involve ongoing dune restoration works across the coastal dune systems.
"The works would focus on improving erosion resilience of the foreshore and improving ecological health.
"Key elements include planting of native dune species, managing priority weeds, dune stabilisation works (such as sand trap fencing), and tree restoration.
"These efforts enhance coastal protection and eco-system integrity."
The third element, "the Beach Nourishment Framework for Ocean-Umina Beach would include a beach monitoring program to assess beach volume across those beaches, and the identification of locations where sand placement would be beneficial to mitigate erosion risk.
"This information would be shared with state government agencies to help inform decision making regarding dredging and beach nourishment works."
The beach maintenance program for Broken Bay beaches "integrates with the Beach Maintenance Program from the Open Coast Beaches CMP", according to the Hawkesbury Nepean Coastal Management Program.
"It includes several key elements, including ongoing beach scraping after storm events, and auditing and upgrading beach accessways (ensuring compliance with the Disability Access Inclusion Plan).
"This would enhance beach management, safety, accessibility, and environmental protection while streamlining maintenance efforts for efficient, ongoing operations."
SOURCE:
Website, 25 Oct 2024
Hawkesbury Nepean River System Coastal Management Program