2.5 Different Kinds of Protection Strategies

Private landowners built rock walls to safeguard their property in the 1960s. They took only transitory and improvised measures. Byron Shire Council then implemented a policy of ’managed retreat’ to counteract sea level rise, which was a long-term approach that did not address the immediate effects or damage to property. The new government indicated that they will abandon the former policy of ‘managed retreat’ and the state-wide, to make it easier for landowners to defend their private property from minor storm occurrences using temporary ‘short-term protection’ methods such as sandbags (Roche, et al. 2013).

They subsequently opted to focus on present SLR hazards such as erosion and storm surges, as well as support local authorities and provide SLR guidance and information. These reforms resulted in a shift in policy from long-term to short-term strategies. Engineering solutions for the medium term were overlooked. Byron shire neglected to address further mediumterm protection options, despite the fact that the sandbags were just short-term solutions.

“The majority of solution’s considered above have overlooked well-established engineering choices, ‘hard’ and’soft’ solutions that can be employed alone or in combination.”

(Roche, et al. 2013)

Later in 2015, some rock walls and groynes were built as hard ‘protective measures’, although this wall failed during a year of high tides in Byron Bay (Roche, et al. 2013). The following are some various ‘protective techniques’ to consider while planning adaption strategies to be robust to the impact of sea level rise.

1. Temporary Protection

Sandbags of various lengths and widths can be used to offer temporary protection on sand beaches. Strong geotextile bags are quite inexpensive as they can be locally filled with beach sand (Scottish Natural Heritage 2019).

Buried sandbags can be an efficient and inexpensive last line of defence in areas prone to mild, seasonal erosion. They are useful for short-term (less than five years) headland protection while other options are designed and implemented, but they should be replaced by a longer-term solution. They have no positive long-term effects on the physical or ecological environment, other from the fact that they are transitory structures that can be simply removed (Scottish Natural Heritage 2019).

Sandbags that are exposed are unsightly and perhaps dangerous. They are ineffective at absorbing wave energy and may hasten local beach erosion. The fill material will leak from damaged bags and return to the beach, but the bags will linger as unsightly waste along the shoreline. Losses will be minimal if the fill material is locally sourced or equivalent to that found on the beach. Sandbags will impede the natural dynamic interchange of material between the beach and dune. They may also interfere with the natural landform and hinder longshore sand transmission. Overall, they cannot be employed as permanent solutions to deal with the effects of SLR and adequately safeguard the shoreline (Scottish Natural Heritage 2019).

2. Soft Protection

The majority of “soft” shore-protection approaches and technologies use natural materials. Beach nourishment, Reprofiling, and dune nourishment are examples of soft methods (Bennington-Castro 2017). The majority of a living shoreline’s footprint is made up of local components. Natural vegetation or other live, “soft” shoreline components such as oyster reefs, rock sills, or massive pieces of wood that are anchored for improved stability, either alone or in combination with stronger shoreline structure, are included.

Living shorelines provide ecological services, such as essential habitat, that promote coastal resilience by stabilising and minimising erosion (NOAA, 2020). Soft shore protection measures can lessen wave impact, slow down chronic erosion, and help reduce wave impact during a storm to some extent. Though soft protection alone will not defend you from a really high storm surge (12 feet) and must be combined with strong protection for the best results (Spiegel 2016).

Living shorelines provide good erosion protection and habitat for coastal species, which encourages its use as a stabilising aid along protected coastlines. Strong storms cause less damage to natural coastal habitats (such as marshes, dunes, mangroves, and coral reefs) than to reinforced shorelines. The abundance of fish and other living creatures important to shorebirds, as well as recreational and commercial uses, is greater in regions with natural coastal environment (NOAA, 2020). An important co-benefit of soft protection like beach nourishment and dune management, is that it retains beach and associated environments, as well as tourism (Everard et al., 2010; Hinkel et al., 2013; Stive et al., 2013; IPCC, n.d.).

3. Hard Protection

Hard engineering solutions involve the construction of artificial structures in an attempt to mitigate the effects of sea level rise on a coastline. Sea walls, rock armour, gabions, and groynes are some examples of this (Bennington-Castro 2017).

When waves collide with hard structures, the energy is reflected to nearby properties rather than dampened. Wave activity erodes the soil at the base, causing it to weaken and disintegrate. Hard protection also degrades the ecosystem and has a negative impact on sensitive coastal life. The wall reduces biodiversity by not providing any habitat. Hard tactics can be costly and require ongoing upkeep (Bennington-Castro 2017). Hard protection provides a high level of protection against violent storms. Hard protection can also provide public spaces such as promenades where people can enjoy the water (Bennington-Castro 2017). When the space is restricted, hard protection is an excellent solution. They can also be multifunctional, combining flood protection with roadways, parking lots, or seaside recreation areas (Stalenberg, 2013 ; van Loon-Steensma and Vellinga, 2014; IPCC, n.d.)

4. Hybrid Protection

Hybrid Protection use both structural and natural stabilisation solutions to make your shorelines more resilient. Bulkheads, geotextile fabrics, poly-mesh, filter socks, coconut fibre logs, and biologs are examples of hybrid approaches (Wiggins, 2018). If you wish to construct a firm coastline, protect the base of the shoreline (which is more prone to erosion), and shield the bank’s slope, hybrid solutions are recommended. A hybrid stabilisation strategy includes more artificial structural features than soft stabilisation solutions. Although hybrid constructions have a greater environmental impact on shorelines than soft shorelines and natural, undisturbed shorelines, they may provide some ecological benefits over hard structures. In coastline reaches with extensive hard shoreline armouring, hybrid structures are preferred over hard structures (Gianou, 2014).