Matt Blacka

• BE Civil (Hons1), MEngSci (Coastal Engineering and Management)
• Group Leader at UNSW Sydney

During the last 50 years, numerous breakwaters along the eastern coast of Australia, and more recently in New Zealand, have undergone construction, repairs, or upgrades using Hanbar concrete armour units. These units are distinct to Australasia, and there is limited information about their properties in standard coastal engineering literature. This...

Infrastructure and climate have important roles in driving the water-energy-food nexus in the Pacific region. The significance of infrastructure is woven throughout the United Nation’s 2030 Agenda for Sustainable Development, with Sustainable Development Goals relevant to infrastructure and its links to the water-energy-food nexus. Pacific Island C...

A monitoring and decision support system has been developed to manage dangerous overtopping of the Marine Parade promenade seawall at Fairy Bower, Manly, Sydney Australia. The seawall fronts 750 m of highly used promenade at the southern end of Manly Beach, and experiences overtopping events that are hazardous to pedestrians and potentially damagin...

Located in the Pacific between Australia and Hawaii, the Republic of Marshall Islands (RMI) is one of the World’s smallest, most isolated and vulnerable nations. Ebeye, a small low-lying and densely populated island on Kwajalein Atoll (Figure 1), is at risk from coastal inundation and erosion due to swell waves and typhoons. Impacts will be magnifi...

2022 marks over two decades since the construction of the Narrowneck multi-purpose reef at the Northern Gold Coast, Queensland. The reef was implemented in 2000 in parallel with 1.1 million m3 of beach nourishment which is one of the most innovative and large-scale coastal management projects in Australia (Boak et al. 2000). Effecting beach managem...

This paper explores the complexity of evaluating the stability of submerged articulated concrete block mats used as seabed scour protection for the footings of monolithic maritime structures. A case study is presented where these mats were installed 50 years ago to prevent wave scour around large concrete caissons, forming the berth foundation of B...

This paper discusses two-dimensional physical modelling of the distribution of vertical wave forces on the underside of a cantilevered walkway slab on top of a proposed vertical seawall in Darwin. The proposed seawall is to be built along the foreshore to protect infrastructure associated with a new luxury hotel from erosion and wave overtopping. T...

On reef mediated coastlines, the interaction of waves and tides play an important role as key drivers of the often complex hydrodynamic processes of the reef and lagoon systems. These interactions are known to be particularly relevant for coral reef fringed island coastlines and atolls, where wave driven flows heavily influence water quality and fl...

Reefs offer natural protection to many coastal island nations through the physical processes of wave breaking on the reef rim and thus, reducing the wave energy that reaches the shoreline. However, both mean and infragravity water levels build up over the reef due to wave breaking on the reef top that can lead to coastal inundation and serious dama...

During the design process for a breakwater, construction and maintenance considerations usually play a major part in determining the final geometry of the structure. This is particularly the case in remote locations with limited availability of materials, plant and machinery combined with the tyranny of distance. This paper presents the design deve...

Estuarine waterways with intermittently open entrances across coastal beaches are typically sheltered environments, with foreshore areas exposed to short period, low-energy wind seas and restricted tidal currents. On occasions, the entrance to the sea breaks open during flood events, scouring the entrance area and flood tide shoals, allowing longer...

Coastal erosion is a perpetual and serious concern for Pacific island countries. Coastal erosion may include various consequences from natural disasters, such as high water levels, sediment impacts on coral reefs, coastal sand extraction on beaches and rivers, and sediment traps. The effects of climate change, such as the rise in sea level, degrada...

Coral reefs provide protection from waves for coastal communities around much of the Pacific region. During modal wave conditions, incoming waves break on the fringing reef edge, such that waves within the reef are considered to be depth limited. During extreme weather events, such as Tropical Cyclones, waves break on the reef slope and dissipate t...

The wave climate on coastlines of many Pacific Island Countries is mediated by fringing coral reef systems that act to naturally reduce wave conditions impacting the coastline. However, during extreme swell and cyclonic wave conditions it has been demonstrated that larger than expected waves can propagate across reefs/lagoons as a result of deep an...

One of our most remote communities, the Chatham Islands, sits 800km off New Zealand's east coast and is home to 600 people. The islands are serviced by a port which provides a lifeline for the community through the provision of every-day goods and export earnings. The port is at the end of its structural life and significant upgrades are necessary....

Management of coastal erosion caused by both natural and anthropogenic drivers is an ongoing challenge for many island nations of the Pacific. While conventional coastal protection techniques have included rock or concrete revetments and seawalls, non-conventional or ‘non-engineered’ protection methods have also been trialled with varying levels of...

The reshaping and loss of land due to coastal erosion is an ever-present concern for Pacific Island Countries (PICs) and may be caused by both natural and anthropogenic factors. Where erosion conflicts with road, maritime, community or aviation infrastructure, these high value assets are put at risk. This infrastructure has high economic value and...

Muttonbird Island and the Coffs Harbour Northern Breakwater attracts over 100,000 visitors each year and is considered one of Coffs Harbour’s most popular and important attractions for tourists and the local community alike. The Northern Breakwater also provides shelter for important assets, services and industries including a Marina and Slipway, W...

During extreme events, island nations with fringing reefs have been seen to experience higher water levels and more powerful bore waves than predicted by standard theory, based on their depth-limited shallow fringing reef conditions. When considering coastal processes in fringing reef situations, coastal engineering practice currently applies empir...

The Australian Government funded research into climate change and institutional adaptation in the Cook Islands as part of Australia’s Pacific Adaptation Strategy Assistance Program (PASAP).

The town of Avarua lies on the cyclone prone north coast of Rarotonga, and is the administrative, economic and tourism capital of the Cook Islands. Previous cyclones impacting Rarotonga, including the unprecedented five cyclones in 2005, have caused significant damage to buildings and threatened infrastructure, raising concerns as to the vulnerabil...

Maintenance and upgrading of existing seawalls for protection against storm erosion and adaptation to climate change are often limited by the availability of 'as-constructed' design drawings. The main failure mode of seawalls is undermining, particularly for rigid seawall structures, in which erosion by wave, tidal and current action causes the bea...

Should management of the coastline be driven by government policy and strategic planning, with nation or state-wide targets for erosion and flood protection? Or should it be driven at a local level, with those people affected by coastal processes determining where money is spent to protect infrastructure and property? This paper explores the approa...

This paper provides a summary of methodologies used to optimise the proposed Gladstone Tug Berth Marina and how, through the application of a risk management framework, SMEC assisted Gladstone Port Corporation's (GPC) decision-making process in understanding risks associated with a 'no breakwater option' and progressing the project. Investigations...

The safety of people in floods is of major concern in floodplain management. Human activity in floodways is inevitable with much development already in flood prone areas. The safety of people can be compromised when exposed to flows which exceed their ability to remain standing or when the vehicles they are travelling in are exposed to flows which...

Accurately determining wave forces acting on marine and coastal structures continues to provide a design challenge for engineers. Empirical techniques, numerical models, and physical models are the main methods used to estimate wave forces on marine structures such as seawalls, caissons, wharves, jetties, pipelines, outfalls, and seawater intakes....

Wave overtopping of coastal structures represents a potential hazard for people, property and infrastructure within the vicinity of wave impact areas. Depending on the acceptable risk and required degree of certainty related to wave overtopping, coastal engineers rely on predictions from semi-empirical desktop methods or physical model studies. Thi...

This paper summarises an investigation undertaken by the Water Research Laboratory and International Coastal Management into wave transmission for low crested geotextile breakwater structures. Structures such as these are being used as an alternative to rock structures or as interim coastal protection structures. These low crested (submerged) detac...

This paper details the methods and results of an investigation into the impacts associated with inundation and sea level rise on a low-lying stretch of road, fronting Ralphs Bay, southeast of Hobart. The South Arm Secondary Road extends from Rokeby to Opossum Bay, and provides the only road access to settlements on the South Arm peninsula with a po...

Recent years have seen the installation and upgrade of many coastal structures using sand filled geotextile containers, both within Australia and internationally. These applications include the construction of artificial surfing reefs, offshore breakwaters, conventional breakwaters, groynes, and seawalls. A limited amount of hydraulic scale modelli...

Failure of seawalls located at the rear of erosion prone sandy beaches is typically caused by scour of beach material from around the seawall toe, due to increased wave and current velocities in this zone. The erosion of this material can result in seawall settlement or collapse due to undermining, as well as a reduction of passive earth forces aga...

The use of models for simulation of many aspects of environmental conditions on the open coast, and within the estuarine environment has been undertaken for many years. Engineers, managers, and decision makers have been using information obtained from both physical and numerical models to better understand environmental processes occurring within t...

Over the past 40 years, many of the breakwaters and revetments on the New South Wales coast have been constructed, repaired, or upgraded with concrete armour units. Since the early 1980s the most widely used armour unit has been the Hanbar. Whilst several applications of the Hanbar unit have been physically modelled, there has been no broad researc...

As the development of urban coastlines progressed, hard form boundaries such as seawalls or revetments were constructed at the rear of many beaches to form a promenade, particularly in the older suburbs of Sydney, Newcastle, and Wollongong. These structures, have served to act as a form of protection for development landward of the beach from wave...

This paper details the range of coastal processes and hazards considered in estimating coastal risk for Clarence City, Tasmania. The work follows on from a first pass assessment undertaken for the entire state of Tasmania by Chris Sharples. The processes considered in this paper include tides and storm surge, extreme open ocean waves, swell wave pe...

A major new hospital is planned for Hobart, Tasmania. The hospital will occupy near-waterfront land which currently operates as a rail yard. Due to the critical nature of the facility and the expected long project life, high values for storm surge, future sea level rise and freeboard were applied as criteria for assessing the suitability of the sit...

This paper details the methods and results of an investigation into the impacts associated with inundation and sea level rise on a low-lying stretch of road, fronting Ralphs Bay, south-east of Hobart. The South Arm Secondary Road extends from Rokeby to Opossum Bay, and provides the only road access to settlements on the South Arm peninsula with a p...

The safety of people in floodways or on flooded streets is of major concern in urban stormwater design and floodplain management. Human activity in floodways is inevitable with much development already in flood prone areas. The safety of people can be compromised when exposed to flows which exceed their ability to remain standing or traverse a wate...