Bienvenue à "l'alerte côtière méditerranéenne" du CAR/PAP ! Ce bulletin est mis à jour mensuellement. Il comprend des résumés des articles récemment publiés et des archives sur des questions environnementales, en particulier celles relatives aux zones côtières. La sélection se fait à partir des articles publiés dans les principales revues scientifiques internationales. Ce bulletin est un excellent moyen pour vous tenir au courant des études et des articles publiés sur les processus côtiers.
This paper introduces the need, in Italian countries, of a real integration of scientific knowledge into coastal policy. Actually, in Italy, still exists a gap between Science and Policy, interfering the implementation of an Integrated Coastal Zone Management (ICZM) process, while there is no coordination between local, regional and national authorities. This lack of an overall strategy has induced some regions to adopt regional plans for the sustainable development of their coastal areas, to compensate the shortcomings of a national planning. Besides, along Italian coasts, there is a heavy landscape urbanization producing conditions of environmental decay and highlighting the risk of erosions in littoral areas. In this critical context, it is necessary to adopt an effective Integrated Coastal Zone Management policy, to connect ecosystem and environmental approaches with the social and economic development of coastal areas. So, in Italian landscape, it is necessary to integrate the national cultural heritage into coastal management, joining scientific and cultural issues. In this framework, ICZM process could play an important role connecting scientists and policy makers towards an effective integration for the social and economic growth of local people.
Keywords: ICZM; Science; Policy; Italy.
Source: N. Cantasano, G. Pellicone and F. Ietto (2017); “Integrated coastal zone management in Italy: a gap between science and policy”, Journal of Coastal Conservation, June 2017, Volume 21, Issue 3, Pages: 317 - 325; First online: 24 April 2017 under DOI:10.1007/s11852-016-0479-z
This study provides an assessment of erosion hazard on the Maltese coast via application of the Coastal Hazard Wheel, a tool that also facilitated analysis of a number of other inherent coastal hazards including ecosystem disruption, gradual inundation, salt water intrusion, and flooding. The CHW characterises the coastal environment by considering geological layout, wave exposure, tidal range, flora and fauna, sediment balance and storm climate. Application of the CHW identified coastal erosion to present a high to very high influence on the Maltese coastline, with 45.7% of the coast exhibiting a low level of erosion hazard, 12.1% a moderate level, 12.6% a high level and 18.4%, a very high level of erosion hazard.
Application of the CHW suggested somewhat higher erosion hazard levels than prior studies using different methodologies; it also confirmed the ease of application of this climate change sensitive coastal hazard identification tool. Management considerations identified a wide range of options the applicability of which is highly dependent on specific coastal configuration and that characterisation of the latter is crucial to allow appropriate management.
The study generated management-useful maps describing coastal susceptibility to various hazards and hazard levels. It further provided a description of the entire Maltese coast in terms of ten different coastal configurations that infer management considerations of six coastal characteristics and five hazards. The study outputs are presented as a contribution to more effective management and decision-making by civil protection and planning agencies and as a key first step in the risk analysis process.
Source: S. Micallef, A. Micallef and Ch. Galdies (2017); “Application of the Coastal Hazard Wheel to assess erosion on the Maltese coast”, Ocean & Coastal Management, In Press, Corrected Proof; Available online: 28 June 2017 under https://doi.org/10.1016/j.ocecoaman.2017.06.005
In this study, HSPF (Hydrologic Simulation Program-FORTRAN) was used to analyze the potential impact of climate change on the streamflow of four major river basins in Ethiopia: Awash, Baro, Genale, and Tekeze. The calibrated and validated HSPF model was forced with daily climate data of 10 CMIP5 (Coupled Model Intercomparison Project phase 5) Global Climate Models (GCMs) for the 1971–2000 control period and the RCP4.5 and RCP8.5 climate projections of 2041–2070 (2050s) and 2071–2100 (2080s). The ensemble median of these 10 GCMs projects the temperature in the four study areas to increase by about 2.3 °C (3.3 °C) in 2050s (2080s), whereas the mean annual precipitation is projected to increase by about 6% (9%) in 2050s (2080s). This results in about 3% (6%) increase in the projected annual streamflow in Awash, Baro, and Tekeze rivers whereas the annual streamflow of Genale river is projected to increase by about 18% (33%) in the 2050s (2080s). However, such projected increase in the mean annual streamflow due to increasing precipitation over Ethiopia contradicts the decreasing trends in mean annual precipitation observed in recent decades. Regional climate models of high resolutions could provide more realistic climate projections for Ethiopia’s complex topography, thus reducing the uncertainties in future streamflow projections.
Source: M.S. Gizaw, G.F. Biftu, T.Y. Gan et al. (2017); “Potential impact of climate change on streamflow of major Ethiopian rivers”, Climatic Change, Pages: 1 - 13; First online: 7 July 2017 under DOI: 10.1007/s10584-017-2021-1
The behavior of surf zone foam holes, as observed at the surface and associated with depth-limited breaking, was investigated. Aerial imagery of the surf zone was obtained with a small, unmanned quadcopter that supported an integrated, high-resolution camera. The quadcopter is an ideal platform for acquiring images directly above the surf zone, a requirement to obtain the requisite resolution. The images were georectified so that size, shape, orientation, and evolution of the wave-generated foam patterns could be quantified. Three hypotheses are proposed for foam-hole generation: obliquely descending eddies (ODEs), self-organization because of bubble rise, and bottom-generated turbulent boils. The fringe region was the most seaward foam region and was marked with circular foam rings that increased in area and were more distinct with time. The fringe region data were consistent with both the self-organization because of bubble rise and turbulent boil mechanisms. The gap region, located between the plunge point and the splash-up created by the bore collapse, was marked by horizontal foam tubes oriented in the cross-shore direction. The foam tubes were likely created in the convergent region between two counter-rotating vortices. The largest region encompassed nearly the entire surf zone and was described as a mat of foam that developed obvious foam holes. The foam holes located in the outer surf zone, near the break point, initially decreased in size, consistent with ODEs before increasing in size and elongation. The foam holes located in the inner surf zone, increased in both size and elongation during a wave period. Because of increasing size with time, the foam-hole generation was attributed to turbulent boils. The rate of increase in foam-hole growth significantly decreased as the waves shoaled from the fringe region in the outer to the inner surf zone, suggesting that growth rate and size decreased with depth.
Keywords: Foam holes; Surf zone turbulence; Breaking waves; Drone remote sensing; Video imaging.
Source: C. A. Benbow, J. H. MacMahan and E. B. Thornton (2017); “Analysis of Surface Foam Holes Associated with Depth-Limited Breaking”. Online ahead of print, Journal of Coastal Research In-Press; Received: 21January 2016; Accepted: 24 January 2017; Revised: 31 March 2017; Available Online under https://doi.org/10.2112/JCOASTRES-D-16-00010.1