Modeling of Caspian Sea Level Change and Feasibility of Sea Water Intake and Outfall Systems Considering Climate Change

Abstract

Climate change significantly impacts water levels, currents and waves, posing challenges for coastal and marine structures including the seawater intake and outfall (SWIO) systems. This study aims to investigate the effects of the Caspian Sea level (CSL) change on the feasibility of SWIO systems until the end of the twenty-first century by examining the changes in wave climate and thermal mixing processes adjacent to coastal structures. Future CSL changes are predicted using an unsteady two-dimensional depth-integrated circulation model, with simulations conducted at decadal intervals up to 2100. Wave climate and thermal mixing processes are numerically modeled based on projections of precipitation, evaporation, Volga River runoff, and outflow to Kara Bogaz Gol (KBG). The methodology is applied to a test case, a SWIO system located at Garabogaz (KBG) on the eastern Caspian coast. Results indicate that the CSL will decrease by 10.67 m at the end of the twenty-first century. By 2030, wave-breaking intensity is expected to surpass design thresholds, and by 2051, thermal discharge is predicted to exceed environmental criteria due to excessive temperature differences between the discharge and ambient seawater.