Detección De Cambios De La Línea Costera Al Norte Del Distrito De Buenaventura Mediante El Uso De Sensores Remotos

Abstract

This study focuses on detecting the magnitude of shoreline changes of the northern District ofBuenaventura, in the Colombian Pacific, over a 30-year period, on a coast where the geomorphologyincludes beaches, cliffs, estuaries, deltas and salt marshes. Satellite imagery (Landsat MSS, ETM + andOLI TIRS) were used to detect historical positions of the shoreline in order to identify the processes ofchange, in terms of erosion and accretion, from 1986 to 2015. Statistical analysis of changes was carriedout to estimate distances and shoreline change rates, using a tool developed by the United States GeologicalSurvey (USGS): Digital Shoreline Analysis System (DSAS). The statistics on Net Shoreline Movement(NSM) and End Point Rate (EPR), provided information about the magnitude and trends of changes in theshoreline. The results indicate that areas with more advanced processes of accretion correspond to sectorsin Boca San Juan, Puerto España and near to La Concepción beach in the Department of Valle del Caucaand in the south of Chavica, in the Department of Chocó; all these sectors are located in the northern partof the study area. Also in the same sectors, particularly around Chavica, the most advanced processes oferosion were found, along with El Choncho beach and a small sector in the Malaga bay. Some sectors ofthe shoreline remained mostly stable, such as Malaga and Buenaventura Bays. Average shoreline changerate of (-) 0.21m per year was found, reflecting its erosive tendency with maximum EPR values 26.92mof accretion and (-) 21.01m for coastal erosion. Natural processes such as the influence of river dischargeand El Niño phenomenon, have contributed to these shoreline changes. The identified erosion and accretionprocesses can be recognized as priority areas of coastal management in the Colombian Pacific.

Evaluation of Coastal Erosion in the Watersheds of Municipality of Buenaventura, Colombia: Using Geospatial Techniques and the Composite Vulnerability Index

“…There was a general trend in coastline accretion according to the average EPR of 2.8 m/year, with a total accretion of 48%. However, the Cifuentes [31] study from 1986 to 2015 showed that, on average, a change rate of −0.2 m/year occurred, reflecting an erosion trend with maximum EPR values of 26.9 m/year of accretion and −21 m/year of coastal erosion. The marked differences in the values of the previous study with those of this study may be explained from the higher temporal coverage used in this work, mainly in the La Concepción beach area.…”

“…Finally, Furlan et al [30] developed a multidimensional CVI to evaluate vulnerability to flood scenarios along the Italian coast considering multiple indicators. Although there are studies that evaluate the general vulnerability of the coasts of Buenaventura [13,21,22,31,32], these have focused mainly on geomorphological and physical dimensions. Numerous studies have been conducted around the world to examine different aspects of coastal vulnerability with a geospatial approach using the CVI and COVI (Table 1).…”

“…The coastline was classified into five relative vulnerability ranges. Cifuentes et al, 2017 [31] focused on studying the magnitude of shoreline change north of Buenaventura District over a 30-year period. On average, they found a rate of change of −0.2 m per year in the coastline, reflecting its erosional trend, with maximum EPR values of 26.9 m of accretion and −21 m of coastal erosion.…”

Regional Patterns of Coastal Erosion and Sedimentation Derived from Spatial Autocorrelation Analysis: Pacific and Colombian Caribbean

“…In Colombia, different studies on coastal erosion have been undertaken, starting with the descriptive analyses carried out by Posada and Henao Pineda [6] and Posada et al [7,8], which generated the first coastal erosion maps of the country from observations of coastal geomorphological features. These studies were later complemented with quantitative analyses through the calculation of changes in coastlines and the use of GIS tools [9][10][11].…”

“…Thus, satellite imagery and shoreline detection have been widely developed and used for a long time, and range from the manual digitization of the coastline to proven automated processes [13][14][15][16]. In the same way, the quantitative evaluation of changes that occur on coasts using tools such as DSAS [17][18][19] has been very popular, and there are countless publications on this [9,11,18,20,21]. The use of this metric requires multiple corrections and rules [22] in order to obtain values close to reality, but before defining which method and tools to use, the objective must be defined; that is, one must define the purpose of this metric, and from that, choose appropriate elements.…”