Oceanologia (Oct 2023)
Assessment of human interventions presence and their impact on shoreline changes along Nile delta, Egypt
Abstract
Coastal erosion is a natural process, that contributed to shaping the Nile Delta shoreline in Egypt over history. The objective of this research is to investigate shoreline changes, accretion, and erosion and to detect particularly vulnerable locations that require immediate attention. Another goal is to assess the efficiency of coastal installations that have been recently implemented along the study area and determine whether they have performed their role to the fullest or need additional modifications. Several Landsat images (TM, ETM+, and OLI) were utilized over 37 years to track the shoreline changes and were analysed using remote sensing (RS) and Geographic Information System (GIS). The digital shoreline analysis system (DSAS) was integrated with the LRR model for assessing historical changes for shorelines from 1985 to 2022 and forecasting future shoreline positions in 2030, 2050, and 2100. Most of the eight zones that make up the Delta region have lately seen the establishment of coastal projects, such as the development of the Abu Qir port's breakwater in 2021. From the results, it was found that the areas around Rosetta promontory, Burullus headland, and Damietta promontory experienced a significant and rapid retreat and with large rates over the study period, with average values of –15.7, –3.25, and –16.8 m/y, respectively. However, both the coast of Alexandria, and Gamasa embayment were subjected to accretion as a prevailing case, with average rates of 2.85, and 4.03 m/y, respectively. Many groins were installed in the east of the Rosetta promontory (zone 3) in 2016 to decrease the erosion process; however, it didn't pay off and could not solve the problem. In contrast, the groins system, which was implemented at the East Kitchener Drain (zone 5) in the same year, lowered erosion rates from 17.6 m/y from 2000 to 2010 to 7 m/y from 2010 to 2022. In 2019, Y-groins built in zone 7, east of Damietta Port, succeeded in slowing rates of erosion. Finally, inlet jetties at El-Gamil (zone 8) were constructed in 2016, resulting in the coastline advancing at 14.7 m/y on average in the period of 2010–2022. The findings of this study confirmed that hard structures are dangerous because they exacerbate the problem of shoreline erosion by disseminating it to the neighbouring beaches and acting as an impediment to the movement of longshore sediments. According to the expected future shoreline patterns, it is necessary for authorities to implement both short-term and long-term protective measures to stop the erosion of several areas of the beach.
