Beach Nourishment with Cost-Benefit Analysis at Tarquinia Lido, Italy

• Tarquinia Lido lies along the Tyrrhenian Sea coast of northern Lazio Region. The beach is approximately 1 km long and 100 m wide following nourishment. 
• The near-shore area contains extensive Posidonia oceanica seagrass meadows covering nearly 900 hectares, important for nutrient cycling and marine biodiversity. 
• The coastline experiences erosion at approximately 1 m per annum. 
• The local economy is heavily dependent on coastal tourism.

To protect coastal infrastructure and maintain tourism revenue through beach nourishment while applying Cost-Benefit Analysis to assess financial, economic and socio-environmental feasibility over multiple decades.

Total project cost: €6 million (2004). Groynes cost €3.8 million; sand acquisition cost less than €5 per cubic metre. Funding provided by Lazio Regional Government through regional taxation. The CBA study recommended alternative financing through beach entrance fees (approximately €0.50 per person per day, generating €84,000 annually) and contributions from beach infrastructure operators (€56,000 annually) to reduce problems and internalise maintenance costs.

• Avoided erosion damage to coastal infrastructure valued at €15.85 million (present value over 50 years).
• Recreational benefits to beach visitors estimated at €3.1 million per year. 
• Direct economic benefits to local beach enterprises valued at €1 million per year. Enhanced storm protection and flood mitigation for backshore properties.

• Implementation of beach nourishment using 450,000 m³ of marine sand to create a 1 km by 100 m beach profile. 
• Construction of five groynes to stabilise sediment. 
• Environmental monitoring and research to track sediment loss rates and seagrass meadow impacts. 
• Application of Cost-Benefit Analysis incorporating ecosystem service valuation, recreational access values and avoided erosion damages.

Simone Martino, Fauna & Flora International, simone.martino@fauna-flora.org

Tarquinia Lido

Tarquinia Lido is a 1 km stretch of sandy beach on the Tyrrhenian coast of Italy's Lazio Region, approximately 90 km north of Rome. The site falls within the Municipality of Tarquinia, which has 18 km of sandy coastline, of which 5 km faces erosion problems. The beach is bounded by the Marta River to the north and the ancient Etruscan port of Gravisca to the south, defining a sediment subcell.

Since the 1990s, the beach had received approximately 120,000 m³ of sand at a cost of €3.5 million. In 2004, a major nourishment scheme was implemented, adding 450,000 m³ of marine sand to extend the beach to 100,000 m², accompanied by five groynes. The total investment reached nearly €6 million, with groynes accounting for €3.8 million and sand costing less than €5 per cubic metre.

The project aimed to address coastal erosion threatening local tourism infrastructure and economic activity. Tourism generates approximately €20 million annually for the municipality, representing 23% of tourism expenditure in the Province of Viterbo. Without intervention, the beach would have returned to its pre-nourishment profile within 15 years, risking damage to backshore properties.

A comprehensive Cost-Benefit Analysis (CBA) evaluated the project over a 50-year period, incorporating not only direct financial returns but also non-market recreational benefits and environmental costs. The analysis calculated the value of erosion damage avoided to coastal infrastructure, recreational access value for beach visitors, and damage to Posidonia oceanica seagrass meadows caused by sediment burial.

Surveys indicated approximately 10% of the near-shore seagrass meadows (covering 900 hectares) were buried within one year of the nourishment. While the CBA showed positive net present value even when environmental damages were included (Benefit-Cost Ratio of 1.77), the research highlighted challenges in distributing costs fairly among beneficiaries. Many beach users from outside the region benefited without contributing to maintenance costs—a "free rider" problem.

The study proposed that beach users contribute to nourishment costs through entrance fees (approximately €0.50 per person per day) and that beach infrastructure operators provide the remainder. This approach would internalise the costs of coastal protection more equitably while recognising that full recovery of environmental damages remains difficult to achieve through current mechanisms.

Valuation of the ecosystem services of beach nourishment in decision making: The case study of Tarquinia Lido, Italy  
Simone Martino, Carl L. Amos
DOI: 10.1016/j.ocecoaman.2015.03.012