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13 NEWS maltatoday | SUNDAY • 13 OCTOBER 2024 JAMES DEBONO jdebono@mediatoday.com.mt Breakwater protection for Marsalforn will damage seagrass A new coastal defence project in Marsalforn Bay, Gozo, is set to bring significant changes to the area, promising better protection from storms and the restoration of the long-eroded beach. But an environment impact assessment reveals that the con- struction of two new breakwaters and rubble groynes will come at a cost to the marine ecosystem, as around 10,300 square metres of protected Posidonia Oceanica seagrass – which play a critical role in supporting marine life and maintaining the health of coastal waters meadows – are expected to be permanently lost. Marsalforn Bay, with its wide, open mouth facing the north- west, is highly susceptible to storm surges and flooding, espe- cially during the harsh northeast and northwest winds prevalent in the region. The current coastal defences are considered inade- quate, leaving the seafront and nearby properties exposed to sig- nificant damage during storms and heavy rainfall events. Water from the Marsalforn Valley flows rapidly through the village, compounding the flooding and leading to frequent infrastructure damage. The pro- posed coastal defence system is designed to mitigate these issues through the reconstruction of the Santa Marija breakwater and the addition of the new Menqa breakwater, along with two rub- ble mound groynes. The structures aim to reduce wave impact, control sediment transport, and create a stable shoreline that can support an extended and replenished beach. If the project goes ahead as planned, the seafront will be far less vulnerable to the destructive forces of storms, thereby protect- ing local businesses and improv- ing the overall safety and usability of the bay area. Project to cover seabed The centrepiece of the project, the Santa Marija breakwater, will extend 207m into the bay and cover an area of 10,421 square metres on the seabed. Con- structed using a combination of concrete caissons, natural rock, and concrete armour units, the breakwater is designed to with- stand the powerful wave forces that currently batter Marsalforn. The structure will also feature a walkway for pedestrians, provid- ing a new recreational space for locals and visitors to enjoy scenic views of the bay. In contrast, the Menqa breakwa- ter, at just 91m long, will be built using a simpler rubble mound design. Together, the two break- waters are expected to transform the water dynamics within the bay, calming the strong currents and minimizing the risk of ero- sion along the shoreline. To further control sediment movement and support beach re- plenishment, two rubble mound groynes will be constructed on either side of the Marsalforn valley's mouth. The groynes, standing up to 4m high and cov- ering 932sq.m, will help stabilise the newly extended beach area, which will span an additional 3,084sq.m. This enhancement is expected to restore the bay's sandy shoreline to a more stable condition, bringing it closer to its historical form. Ecological concerns: loss of Posidonia meadows While the breakwater and groyne construction promise enhanced coastal protection and beach restoration, the EIA report from AIS highlights a major eco- logical drawback: the irreversible loss of Posidonia Oceanica mead- ows. These underwater meadows, often referred to as the "lungs of the sea" for their role in produc- ing oxygen and supporting ma- rine life, will be significantly im- pacted by the construction. The Santa Marija breakwater alone is expected to destroy around 10,300sq.m of these habitats, which are not only protected at a national and European level but are also listed as endangered un- der the Barcelona Convention. The loss of Posidonia meadows is of critical concern because of their slow rate of natural recovery. The EIA notes that recolonisation can take decades, if not longer, making the impact effectively permanent. This loss is particularly troubling given that these meadows provide refuge and foraging grounds for numerous marine species, includ- ing fish that are important to the local fishing industry. To mitigate the damage, the EIA recommends considering compensatory measures such as transplanting adult Posidonia plants or planting seeds in de- graded areas around the site. However, these options are fraught with challenges. Trans- plantation is a costly and la- bour-intensive process with un- predictable survival rates, while seed planting requires controlled conditions that are difficult to replicate in the open sea. As a re- sult, even the most well-executed mitigation efforts may not fully compensate for the loss. Visual impact on Marsalforn's seascape Beyond the ecological implica- tions, the new breakwaters will also transform the visual land- scape of Marsalforn Bay. The EIA categorises the impact on key viewpoints as "major ad- verse", noting that the imposing presence of the breakwaters will disrupt the natural openness and visual flow of the bay. The extension of the coastal promenade into the bay will be highly visible, altering the char- acter of Marsalforn's previously unobstructed maritime environ- ment. Additionally, the improved shelter provided by the breakwa- ters is likely to attract more vessels to the area, potentially resulting in visual clutter and congestion. Modifying water circulation The construction of the break- waters will also alter water cir- culation patterns within the bay, with both positive and negative consequences. On the positive side, calmer waters will lead to a reduction in wave-induced erosion, making the shoreline more stable and re- ducing the risk of infrastructure damage. Sediment from the Mar- salforn Valley will settle more quickly, which could increase the available sandy beach area over time. However, these changes will al- so mean that floating debris and waste discharged during heavy rain events could become trapped within the bay, leading to po- tential water quality issues. The breakwaters will disrupt the bay's natural flushing mechanism, po- tentially affecting marine habitats and water clarity. Photomontage showing a view of Marsalforn Bay today (top) and with the two planned breakwaters and rubble groynes