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The original article has been corrected: Legends in Fig. 7 in the article and legends in Figs. 9 and 10 of Supplementary Material 1 as well as contents in columns H and J of Supplementary Material 2 have been amended to the valid results.

In this contribution we investigate the hydrodynamic response in Alfacs Bay (Delta Ebro, NW Mediterranean Sea) to different anthropogenic modifications in freshwater flows and inner bay-open sea connections. The fresh water, coming from rice field irrigation, contains nutrients and pesticides and therefore affects in multiple ways the productivity and water quality of the bay. The application of a nested oceanographic circulation modelling suite within the bay provides objective information to solve water quality problems that are becoming more acute due to temperature and phytoplankton concentration peaks during the summer period, when sea water may exceed 28 ˚C leading high rates of mussels mortality and therefore a significant impact on the local economy. The effects of different management solutions (like a connection channel between the inner bay and open sea) are hydro-dynamically modelled in order to diminish residence times (e-flushing time) and water temperatures. The modelling system, based on the Regional Ocean Modelling System (ROMS), consists in a set of nested domains using data from CMEMS-IBI for the initial and open boundary conditions (coarser domain). One full year (2014) of simulation is used to validate the results showing low errors with SST and good agreement with surface currents. Finally, a set of twin numerical experiments during the summer period (when water temperature reaches 28 ˚C) are used to analyse the effects of proposed nature-based interventions. Although these actions modify water temperature in the water column, the decrease in SST is not high enough to avoid high temperatures during some days preventing eventual mussel mortality during summer in the shallowest regions. However, the proposed management actions reveal their effectiveness in diminishing water residence times along the entire bay, thus preventing the inner areas to have low renovation and the corresponding ecological problems.

Beach profile modeling is still a task undergoing development. Because of the simplifications required to the present day conventional models, the applicability to real world problems remains limited. In addition, a lot of physical parameters are involved in the application process, introducing unknown percentages of uncertainty and even randomness. The main aim of this paper is, therefore, to quantify the overall uncertainty in profile dynamics predictions. More specifically, the paper will quantify the contributions of wave, current, turbulence, sediment transport, etc. predictions to this uncertainty. This will allow a scientific and engineering reading of the problem building "blocks" in a profile model. For this purpose and in order to make the exercise more useful, a widely used and tested profile model (SBEACH) has been selected. This paper is the first of a set checking all the involved parameters. INTRODUCTION A real profile on the Catalonian coast has been used. SBEACH model has been used varying all the parameters involved in its predictions, in the full range of validity, which the model accepts. Civil Engineer. Head of the Coastal Engineering Dpt. ALATEC-PROES, S.A. Virgen del Puerto, 5. 28005 Maddd (Spain). Tel.: § 91 366 59 59 http://www.alatec-proes.es. Email: jose.medina@alatec,es 2 Ph.D. Civil Engineer. Laboratod d'Enginyeda Maritima. Universitat Politecnica de Catalunya. Jordi Girona 1-3. Campus Nord Ed.DI. 08034 Barcelona, Spain, Phone: § 93 401 64 68; Fax: +34 93 401 73 57. Email: a gustin.arcilla~,upc,es_ 3 Ph.D, Marine Sciences, Laboratori d'Enginyeria Maritima. Universitat PolitecnJca de Catalunya. Email: Jose.Jimenez(~,upc.es

The use of different optical systems based on computer vision approach, for measuring swash zone morphological changes, is here proposed. In particular, such techniques are able to achieve quite accurate 2D and 3D reconstruction of the sandy bottom in dynamic conditions under regular waves. They are considered truly non-invasive, since there is no interaction of the hardware with the water motion. The optical techniques have been applied both at small and at large scale facilities for the investigation on the seabed interaction with the fluid motion within the swash zone. The performances of well-established more traditional measurement instruments have been compared with the proposed optical instruments both at small and large scales. In both cases satisfactory results have been gathered during the present experimental campaign.

Il lavoro riporta i risultati della sperimentazione condotta su un modello in scala 1:40 di un intervento di protezione della costa a realizzarsi presso Aspra (PA)