The spatiotemporal shoreline dynamics of a delta

The construction of dams on rivers feeding deltas has caused rapid shoreline retreat of many deltas around the world. To show that the retreat has been due to anthropogenic effects, it is very important to observe the natural shoreline changes before the dams effects on a delta. This study investigated shoreline changes in the Seyhan Delta in the Eastern Mediterranean from 1950 to 2018 employing long-term Landsat satellite images and aerial photographs. The results indicated that the shoreline accreted nearly +131 m with a maximum rate of +22.9 m yr−1 from 1950 to 1956. In this period an area of +322 071m2 was added to the delta. Contrary to this, following the construction of the Seyhan Dam in 1956, the Seyhan Delta lost a total area of -4 039 251m2 from 1956 to 2018. The shoreline retreated −2293 m at the river mouth, with a maximum rate of retreat of −37 m yr−1. The major cause of this retreat is the trapping behind the Seyhan Dam of sediments transported by the Seyhan River. In the future, it is expected that the shoreline will retreat even more rapidly from causes such as the construction of further planned dams, deltaic subsidence and rising of global sea level. This situation will have a great impact upon wetland areas and upon agricultural and tourism areas and structures in the delta.

Figure 1.jpg

Figure.  (a) Study area in the Eastern Mediterranean Sea with the bathymetry, wave direction, longshore current and three constructed dams (c.y. imply that dam construction year). Bathymetric data were obtained from EMODnet (http://www.emodnet.eu) (b) 2018 Landsat imagery showing the historical shoreline positions used for analyses in this study.

Highlights

  • Shoreline changes in Seyhan Delta from 1950 to 2018 were investigated with Landsat time series and aerial photographs

  • The shoreline accreted between 1950 and 1956 but continuously retreated from 1956 until 2018.

  • The major factor in retreat of the shoreline was the Seyhan Dam constructed in 1956.

  • Seyhan Delta is witness to the fastest shoreline retreat in Turkey.

​​Publications related to this research:

Özpolat, E., Demir, T., (2019). The spatiotemporal shoreline dynamics of a delta under natural and anthropogenic conditions from 1950 to 2018: A dramatic case from the Eastern Mediterranean. Ocean & Coastal menagement , (180) 104910.  https://doi.org/10.1016/j.ocecoaman.2019.104910

Abstracts and presentations related to this research:

Özpolat, E., Demir, T., (2019) Anthropogenic effect or natural limit? Shoreline changes of a delta from accretion to destruction: A case from the Eastern Mediterranean INQUA 2019 General Assembly Conference Abstracts