The swim-survey archive of the Mediterranean rocky coasts: Potentials and future perspectives

The Geoswim programme is an expedition-type project which is aiming to survey, monitor and measure the entire perimeter of rocky coasts of the Mediterranean Sea. The project officially started in 2012 with the first one-man survey of 193.4 km by snorkeling along the northeastern Adriatic coasts, and is ongoing. So far, 559.5 km of rocky coasts have been surveyed, over 98 days of survey, and several hundred thousand time-lapse images, continuous videos and outline images have been collected, both above and below the waterline. Bathymetric data and physical/chemical parameters, such as temperature and electrical conductivity have also been collected during the snorkel surveys. Instruments are hosted on a specially-built raft, called instrumental-supported raft (ISR). The data are not homogeneous because over the years the approach has changed following the introduction of new technologies and some redesign of the instruments used, and, in part, also the type of data collected. Moreover, observational data for use in coastal studies and for integrating instrumental data are collected. The paper presents and take stock of the geometry of the database and discusses the main results of the Geoswim programme. Data analysed highlighted that the database is a significant archive that provides 1) images and videos as a baseline for subsequent comparisons, 2) large amount of images to be used to build 3D models of coastal landforms, 3) data for statistics, and 4) a valuable source of possible discoveries of unknown coastal objects, such as sea caves, tidal notches at unexpected sites, ecological observations, etc.