Abstract:

The scope of the present research is to examine the spatial consequences of the predicted future sea-level rise upon the active area of the delta of the River Acheloos, which forms part of the NW coast of the Gulf of Patras (Ionian Sea). The growth of the Acheloos River deltaic plain, prior to the construction of dams and channelization of the lower part of the river, took place through the progradation of four main distributaries which transported 5-6 million tones of sediments annually.
Following the construction of the dams, the hydraulic regime of Acheloos has changed and its propagation has ceased. The present investigation aims to quantify coastal changes on the deltaic plain of the Acheloos river due to the combined effect of (i) the process of inundation induced by a future sea level rise of 0.5 and 1 m and (ii) coastal erosion caused by the increased exposure to wave action due to sea-level rise and subsequent coastline retreat. The results of our analysis show severe shoreline recession (up to 1900m), extensive submergence of the active deltaic plain (~ 2586⋅103 m2 or 61.4 %) and elimination of most of the lagoonal areas. The substantial loss of deltaic land, accompanied by salinisation of the groundwater table, will cause severe damage to the agricultural economy of the area. Furthermore, we show that the consequences of a future sea-level rise on a low-relief fluviallydominated delta cannot be predicted accurately by simple conceptual models; instead, a holistic approach incorporating topographic, geomorphological, sedimentological, morphodynamic and hydrodynamic analyses is required.