Error! No text of specified style in document. Advisian Error! No text of specified style in document. Error! No text of specified style in document.Error! No text of specified style in document. B.1 Open Coast – Physical and Environmental Context B.1.1 Physical features The Shoalhaven open coast extends 165 km along the NSW south coast, from Shoalhaven Heads to North Durras. Shoalhaven City Council manages 40 of Shoalhaven’s 109 beaches and 9 of its 14 estuaries, over a 165 km stretch of coastline. This is the largest stretch of managed coastline within any local government area in NSW. Ten of the beaches managed by Council are classified as being at high risk to coastal hazards, together with ten cliffs and bluffs. As a result, many of the studies and much of the risk management and mitigation works, have focussed on these areas. It is expected that the focus will need to expand into the future as more locations are impacted due to a changing climate. In addition, the remaining Council-managed open coast beaches will need to be considered in the CMP not only from a risk management and mitigation viewpoint, but from a social, environmental and cultural perspective also, as captured by the four coastal management areas described in the new Coastal Management SEPP. The following 10 beaches were prioritised for coastal hazard studies after being risk assessed for a 1% (100 ARI) coastal storm event in the 2004 Coastline Risk Management Report: • Shoalhaven Heads • Culburra Beach • Warrain Beach • Currarong Beach • Callala Beach • Collingwood Beach • Boat Harbour, Bendalong • Narrawallee Beach • Mollymook Beach • Collers Beach. Physical descriptions of each of these beaches have been drawn from Shoalhaven Coastal Hazard Mapping Review prepared by Advisian (2016). 1. Shoalhaven Heads. Shoalhaven Heads is a small coastal town located on Seven Mile Beach at the foot of Mount Coolangatta and on the northern side of the Shoalhaven River entrance, a natural and untrained entrance. Seven Mile Beach is bounded by the town of Gerroa to the north, Crookhaven Heads to the south, Berrys Bay to the east and national parks inland. The most at-risk urban asset is the Sur Club, which came under threat during the storm and flooding event of 1978. The dunes at Shoalhaven Heads have previously undergone erosion due to the Shoalhaven River entrance’s behaviour during storms and flooding events stripping away sediment from the beach. Historically, the Shoalhaven Council’s policy is to maintain a v-shaped notch through the berm on Shoalhaven River entrance to influence the opening of the entrance at high water levels and alleviate flooding Appendix B – DRAFT Shoalhaven CMP Scoping Study Advisian 2 of 78 concerns. The influence of the entrance on the sediment budget of Shoalhaven Heads makes the beach a particularly unique one among the open coast. 2. Culburra Beach. Culburra Beach is located to the north-east of Wollumboola Lake and bound by Crookhaven River entrance to the north and Penguin Head to the south. Urban development along the beachfront is located behind highly vegetated dune which has undergone erosion due to storm cut and aeolian sediment transport. 3. Warrain Beach. Warrain Beach is a 10-kilometre-long open-coast beach located north-east of Jervis Bay. The beach is bounded by Penguin Head to the north and Cuurarong Head to the south. The location of Kinghorne’s Point along the midpoint of Warrain Beach means that the beach is separated into two distinct sediment compartments. 4. Currarong Beach. Currarong Beach is a 900m long beach located between the Currarong River entrance on the east and a bedrock outcrop on the west. There is a prominent rock outcrop midway of the beach which has formed a small salient influencing the beach morphology. Storm erosion and wave runup has eroded the dune to a steep shape. 5. Callala Beach. Callala Beach a 5-kilometre-long beach lo northern shore of Jervis Bay flanked by Callala Point to the north and Tapalla Point to the south. It is subject to ocean swell. However, wave climate at Callala Beach is much reduced, as it is in a semi-enclosed embayment, compared with that which, typically, is experienced on open-coast beaches along Shoalhaven City coastline. The incipient and frontal dune along have remained in a natural state, relatively undisturbed and covered in natural vegetation. However urban development has since reshaped and stripped the dune vegetation. Hard protection has been constructed on some areas of the dune to protect property from erosion. 6. Collingwood Beach. Collingwood Beach is located on the western shores of Jervis Bay and bounded by Moona Moona Creek entrance to the north and Orion Beach to the south. The beach is subject to ocean swell waves and wind waves, however like Callala beach, the ocean swells are less impactful than those experienced on the open coast. Dune vegetation along parts of Collingwood Beach has been deliberately damaged, causing the dunes to be more susceptible to erosion in future storms. 7. Boat Harbour Beach, Bendalong. Bendalong Boat Harbour Beach is located in Bendalong on the northern side of Red Point. The beach is approximately 300 metres long and is flanked by Red Point to the east and a rocky point on the west, separating the embayment from Washerwoman Beach to the west. The beach includes a range of facilities including a boat ramp, picnic areas, car parking, children’s play area and a toilet block, and is a very popular destination for boating, fishing and other ocean-based recreation. 7. Narrawallee. Narrawallee Beach is an open-coast beach located north of Ulladulla on the Shoalhaven coast. The beach is approximately 1.4 kilometres long and is flanked by an intertidal rock shelf at the southern end, and the sandstone headland of Preservation Rock and Narrawallee inlet at the northern end. The entrance to Narrawallee inlet is currently located to the north of Preservation Rock, and there is a prominent rock outcrop near the centre of the beach that has resulted in the formation of a salient. The southern end of the beach is flanked by a steep escarpment or bluff, and urban development, located behind a vegetated dune, flanks the northern half of the beach. Appendix B – DRAFT Shoalhaven CMP Scoping Study Advisian 3 of 78 8. Mollymook. Mollymook Beach is an open-coast beach located north of Ulladulla on the Shoalhaven coast. The beach is approximately two kilometres long and is flanked by a rocky sandstone headland of Bannisters Point at the northern end and an intertidal rock shelf to the south. Two small creeks cross the beach, one towards the southern end and another near the northern end. The entire beach is flanked by urban development and in some areas, the frontal dune has been interfered with, reshaped and denuded of natural vegetation, especially at the southern end where the Golf Club and Surf Club are located. Here, seawall structures have been constructed on the dune to protect property from erosion. A dune has been recently constructed (April 2016) using sand sourced from dredging at Lake Conjola, on the northern side of Blackwater Creek, as well as a revetment constructed of rock and geobags. These works have reduced the coastal erosion and inundation hazard for the properties immediately north of the creek entrance, as well as reduced the propensity for the creek to break out towards the north along the beach. 9. Collers Beach. Collers Beach is located on the northern side of Ulladulla Head south of Mollymook Beach. The beach is approximately 150 metres long and is flanked by rocky headlands. The nearshore seabed comprises mainly rock reef. The beach is backed by the Mollymook Golf Course and there is a small residential subdivision on an elevated bluff to the north. On the northern side also are a car park and the start of a coastal walkway around to a local swimming hole (the Bogey Hole) and Mollymook Beach. There are some properties located behind the dune at the southern end of the beach. B.1.2 Sediment Compartments Carvalho and Woodroffe (2015) have undertaken a study of the coastal compartments of the eastern coast of NSW. They considered sediment compartments as subdivisions of the coast separated by major obstacles such as headlands, which stop longshore transport of sediment. Compartments were delineated based on physical characteristics as well as review and interpretation of hydrologic, geomorphic and sedimentological data. The following primary sediment compartments were identified for the Shoalhaven coast: • A compartment centred on the Shoalhaven River estuary, encompassing Seven Mile Beach at Shoalhaven Heads, Culburra, Warrain and Currarong beaches; • A compartment centred on Jervis Bay, encompassing Callala and Collingwood beaches; • A compartment between Bannisters Point and Jervis Bay, encompassing Narrawallee beach; • A compartment between Warden Head and Bannisters Point, encompassing Ulladulla Harbour, Collers and Mollymook beaches. These compartments have been further subdivided into secondary and tertiary sediment compartments by the presence of smaller headlands and based on sediment characteristics and transport. The Shoalhaven coastal compartment is dominated by the Shoalhaven River which is responsible for delivering significant quantities of sediment to the beaches in the compartment; with sand transport to the north limited by the presence of Black Head and sand transport to the south blocked by Beecroft peninsula. Appendix B – DRAFT Shoalhaven CMP Scoping Study Advisian 4 of 78 McPherson et al. (2015) have delineated the coastline into similar sediment compartments when compared with those presented in Carvallo and Woodroffe (2015) – they identified secondary sediment compartments centred on the Shoalhaven River, Jervis Bay and a compartment between Ulladulla and Jervis Bay based on baseline reference data sets and a workshop with coastal experts.