Salt-Wedge Dynamics In Microtidal Neretva River Estuary

The Neretva River estuary, located in Croatia, on the eastern coast of the Adriatic Sea, is a typical example of a micro-tidal salt-wedge estuary. Here, the salt-wedge dynamics was investigated based on continuous field measurements and numerical modeling for the period 2015-2018. A two-layer shallow-water numerical model proved to be an accurate and reliable tool for computing the salt-wedge dynamics in the Neretva River estuary. The simulations showed that the river inflow has the strongest impact on the salt-wedge dynamics, whereas sea levels and tides have a much smaller effect, mainly related to daily variations of the salt-wedge length and volume. A set of simple equations were derived, which link the salt-wedge intrusion length, salt-wedge volume, and salt-wedge spread to the river flow rate. It was shown that, during summer, the salt-wedge intrudes more than 20 km upstream from the mouth, exacerbating the salinization of aquifers and soils. The assessment of salt-wedge dynamics in the Neretva River estuary is thus a crucial element for planning, designing, and managing the irrigation system in this coastal region, for sustainable development of agriculture and protection of water resources. (C) 2021 Elsevier B.V. All rights reserved.