Modelling water exchange in the Flommen lagoon, southern Sweden
The Flommen Lagoon, southern Sweden, is a unique water body of great ecological and economic values. Thus, its protection against flooding and its water quality maintenance has always been a concern. The objective of this study was to investigate the water exchange between the lagoon and the sea with regards to the inlet properties and the existent sluice gate operation. An investigation was also performed about the impact of opening a second inlet on the water renewal. According to the simulation results, the inlet geometry showed no significant influence on the lagoon water level but affected the water exchange rate. For the simulated time period, halve the cross-section area decreases the gross exchange rate by 39.2% and double cross-section area increases the gross exchange rate by 15.3%. The sluice decreases the gross water exchange rate by 31.6%, but it plays an important role in protecting the golf courses around the lagoon from flooding. With two inlets, the gross water exchange rate is 15.3% higher than with one inlet, and the water level is also slightly higher.