ENGINEERING GUIDELINES FOR NATURE-BASED SOLUTIONS TO MITIGATE SALT INTRUSION

Worldwide, deltas are attractors of life. Due to their provision of freshwater and fertile land while having an open connection to the sea, deltas have become some of the most densely populated and heavily utilised systems in the world. Thereby, deltas—and the estuaries within—are of interest to a wide variety of stakeholders. The crucial functions of deltas are strongly related to the natural dynamics of these systems, e.g., the availability of freshwater and flood safety. At the same time, these natural dynamics are dominated by complex, nonlinear relations in which the interests of all the stakeholders is a delicate balance. Generally, the socio-economic and flood safety functions in a delta are well-accounted for in the po- litical arena and in engineering practice. However, in recent years, the threat of droughts and the resulting lack of freshwater availability has gained traction. Where research on and practice of nature-based solu- tions have mainly addressed their use for flood safety, freshwater availability has largely remained out of the picture. As freshwater availability is linked to salt intrusion, here we present engineering guidelines to mitigate salt intrusion in estuaries using nature-based solutions.