Figure 3
From: Modelling Holocene analogues of coastal plain estuaries reveals the magnitude of sea-level threat
Key representative maps comparing maximum salinity reached relative to sea level, bathymetric surface, discharge and barrier morphology. (a) An increase in sea level from WL0 present-day conditions (IV–VI) to WL2 Holocene highstand conditions (I–III) significantly increases marine incursion, extending to the upper reaches of Lake Alexandrina and pushing the brackish limit further up the Murray Gorge. There is negligible change to the overall palaeo-environmental character of the region between end-member and best-estimate Holocene bathymetries (I–III or IV–VI). (b) Variance in flow from drought (D−) to flood (D+) scenarios (I–III) is unable to alter the palaeo-environmental character of the region. (c) Variance in barrier morphology from completely open (B0) to modern-day (Bmod) outlet scenarios (I–IV) is also unable to alter the palaeo-environmental character of the region. The isohaline (black line) delimits the brackish limit (equivalent to 1 psu) with the percentage area of each salinity class seaward of the isohaline given relative to total inundated area. The hatched box highlights the common scenario between the three panels: scenario SmidWL2DavBmod. Within (a) all maps shown are pre-regulation average discharge with modern-day barrier morphology scenarios (I: scenario SupWL2DavBmod; II: scenario SmidWL2DavBmod; III: scenario SlowWL2DavBmod; IV: scenario SupWL0DavBmod; V: scenario SmidWL0DavBmod and VI: scenario SlowWL0DavBmod; Table S1). To demonstrate representative salinities at the Holocene highstand, SmidWL2 scenarios are shown within (b) (I: scenario SmidWL2D-Bmod; II: scenario SmidWL2DavBmod; III: scenario SmidWL2D+Bmod) and (c) (I: scenario SmidWL2DavB0; II: scenario SmidWL2DavB+; III: scenario SmidWL2DavB++; IV: scenario SmidWL2DavBmod). Salinity is measured based on the classification scheme of Tooley51.
