The Volturno coastal Plain (VP), laying from Mondragone town and Lago Patria (Southern Italy), was intensely modified by antrophic activities mainly in the last centuries; crops and urban zones took the place of natural lands. The urban sprawl as the events associated to the global warming and local climate deteriorations (relative sea level rise, storm surges, river flood) are the main causes of coastal erosion. During the last 3-4 ka, VP has experienced an increase in sedimentary input, a substantial slowdown of sea level rise rhythms and a progressive seaward shift of coastline and barrier-dunes-lagoon systems. In particular, the delta system development and the strongest coastal progradation phase (about 2 km) started from Roman period (ca. 2.5 ka B.P.) and reached the apex between c.a.1500-1800 A.D. coinciding with the period called Little Ice Age. From historical maps, aerial photographs, topographic maps and satellite images covering the 1817-2012 time span, 10 shorelines were delineated. Along 165 transects spaced 200 m apart, the shoreline variations and the trends were assessed; the first was calculated for each pair of two consecutive shorelines, while the latter by using all the shorelines available for the 1957-1997 and 1997-2012 time windows. In the first time window, both sides of Volturno river mouth and the Ischitella locality were in erosion. At the beginning '60s, the Volturno coastal zone was deeply modified by the antrophic pressure, 4 rivers cross-sections and 10 dams were built in the Volturno basin. Moreover, since the '70s, the urban environment expanded rapidly and the construction of seaside tourist center Pinetamare took place. In order to preserve the beaches and the houses very close to the shoreline, several coastal defences were also built from 1978 to 1979 nevertheless they stabilized the Pinetamare zone but increased the erosion in Ischitella locality. In the 1997-2012 period, moving from Lago Patria toward Mondragone city, a first coastal sector was in erosion (-1.4 m/year), the area of Pineta Mare was characterized by stability (0.6 m/y), northward an accretion rate of 2m/year was recorded. At Volturno river, the left side was in erosion (mean value = -2 m/y) while the right side in accretion (mean value = 1.4 m/y). Still moving northward, there are other two sectors, the first was characterized by a rate of -2m/year and the last by a rate of 1m/year. At present, the coastal defences do not work well, they are for the greatest part under seawater; this condition favor the establishment of sectors in erosion alternate with those in accretion. The knowledge of both historical evolution and of present day shoreline trend at VP can be considered a vital tool to support the development of a coastal system able to adapt and cope with natural hazard and to improve its naturalness.
Historical evolution of Volturno coastal plain and current shoreline trend as tools for territorial management
Alberico I;Cavuoto G;Di Fiore V;Punzo M;Tarallo D;Pelosi N
2016
Abstract
The Volturno coastal Plain (VP), laying from Mondragone town and Lago Patria (Southern Italy), was intensely modified by antrophic activities mainly in the last centuries; crops and urban zones took the place of natural lands. The urban sprawl as the events associated to the global warming and local climate deteriorations (relative sea level rise, storm surges, river flood) are the main causes of coastal erosion. During the last 3-4 ka, VP has experienced an increase in sedimentary input, a substantial slowdown of sea level rise rhythms and a progressive seaward shift of coastline and barrier-dunes-lagoon systems. In particular, the delta system development and the strongest coastal progradation phase (about 2 km) started from Roman period (ca. 2.5 ka B.P.) and reached the apex between c.a.1500-1800 A.D. coinciding with the period called Little Ice Age. From historical maps, aerial photographs, topographic maps and satellite images covering the 1817-2012 time span, 10 shorelines were delineated. Along 165 transects spaced 200 m apart, the shoreline variations and the trends were assessed; the first was calculated for each pair of two consecutive shorelines, while the latter by using all the shorelines available for the 1957-1997 and 1997-2012 time windows. In the first time window, both sides of Volturno river mouth and the Ischitella locality were in erosion. At the beginning '60s, the Volturno coastal zone was deeply modified by the antrophic pressure, 4 rivers cross-sections and 10 dams were built in the Volturno basin. Moreover, since the '70s, the urban environment expanded rapidly and the construction of seaside tourist center Pinetamare took place. In order to preserve the beaches and the houses very close to the shoreline, several coastal defences were also built from 1978 to 1979 nevertheless they stabilized the Pinetamare zone but increased the erosion in Ischitella locality. In the 1997-2012 period, moving from Lago Patria toward Mondragone city, a first coastal sector was in erosion (-1.4 m/year), the area of Pineta Mare was characterized by stability (0.6 m/y), northward an accretion rate of 2m/year was recorded. At Volturno river, the left side was in erosion (mean value = -2 m/y) while the right side in accretion (mean value = 1.4 m/y). Still moving northward, there are other two sectors, the first was characterized by a rate of -2m/year and the last by a rate of 1m/year. At present, the coastal defences do not work well, they are for the greatest part under seawater; this condition favor the establishment of sectors in erosion alternate with those in accretion. The knowledge of both historical evolution and of present day shoreline trend at VP can be considered a vital tool to support the development of a coastal system able to adapt and cope with natural hazard and to improve its naturalness.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
