In the RISC-KIT Case Study area of Emilia-Romagna (Italy), a study has been undertaken to gain insights about improvements of the design of beach scraping operations. Here, a numerical modeling approach was used to find more appropriate beach scraping design.
Based on the study of Harley and Ciavola (2013): Managing local coastal inundation risk using real-time forecasts and artificial dune placements, Coastal Engineering, Volume 77, Pages 77-90,
Two test sites along the Emilia-Romagna coastline were chosen for the study. These two coastal areas are characteristic of this region in that they both contain low-lying sandy beaches and have a large amount of beach-front infrastructure built to service tourists. Coastal inundation is a persistent problem at both sites and has been exacerbated over the past 60 years. Subsidence, along with decreasing sediment supplies to the coast from rivers such as the Fiumi Uniti, have seen the shoreline recede in this area of up to 300 m since 1943 (Preti, 2007).
On the coastline of Emilia-Romagna, ‘hard’ and ‘soft’ engineering practices have been implemented. With regards to hard engineering practices, measures like emerged and submerged detached breakwaters, groins and sea walls are implemented. Beach nourishment, as soft engineering solution, has been regularly undertaken. On a small scale, beach scrapings were used to create ‘winter dunes’. These were undertaken by private initiatives, so about this relatively ad hoc approach little is known about the ability of these temporary artificial dunes to resist different types of storm events.
For the study, two test study sites in Emilia-Romagna were examined. While at the first area artificial dunes are constructed every winter by beach scraping, the second area only minor dune constructions are currently undertaken. The construction of the dunes at the first study area over the 2011/2012 winter period were the subject of a beach monitoring program. It was designed in order to measure artificial dune formations and their ability to resist storm events over that time interval. The monitoring process showed the behavior of the created dunes over the winter period. A numerical model was used to not only forecast the potential for coastal inundation and dune failure, but to simulate different “what if” scenarios that could be used to optimize their placement and undertake any emergency dune-strengthening measures prior to storm arrival.
The results of the modeling suggest that numerical modeling approach is appropriate for beach scraping design. It was demonstrated that the used model has the potential to simulate both the complex hydrodynamic processes surrounding detached breakwaters on this coastline as well as dune erosion and breaching. In this way, the modeling can help to improve the efficiency of beach scraping procedures.
More detailed information on the results and be found here: http://www.sciencedirect.com/science/article/pii/S037838391300046X
Preti, M., 2007. Stato del litorale emiliamo-romagnolo all'anno 2007 e piano decennale di gestione (Emilia-Romagna littoral state in 2007 and ten years management plan). Arpa Emilia-Romagna.