River Sediment Input to the Moín Bay at the Site of the New Moín Container Terminal in Costa Rica

Since the year 2015 a new Container Terminal is being built in the Moín Bay on the Caribbean coast of Costa Rica. The first stage of the works consists mainly of a 40-Ha reclamation area and a 1.5-km breakwater. The concession of this public facility was awarded to APM Terminals and construction has been executed by the Dutch consortium Van Oord / BAM International.

The protruding reclaimed area is expected to have a morphological impact on the coastal sediment dynamics. The mouth of the Moín river is located to the east end of the bay and provides an important input of silts and fine sands originating from an 80 km² tropical river basin.

The Tropical Science Center (CCT in Spanish), a renowned Costa Rican scientific and environmental NGO, has overseen the environmental management and monitoring of the project for APM Terminals during its construction phase. Important efforts are being directed towards the quantification of the sediment input of the Moín river to the bay, in order to generate a baseline for future decision-making about the river and estuary in the context of the new harbor that is being built.

A state-of-the-art fixed side-looking acoustic Doppler current profiler was installed close to the mouth of the river, alongside a turbidity sensor, which together provide real-time measurements of discharge and suspended sediment concentration in the lower end of the estuary. Tidal effects being considered, the hydrological station has allowed estimating the net sediment input to the bay and quantifying the role of single events -tropical storms and cold fronts- to the total sediment that will eventually be deposited in the harbor area of the new Container Terminal.

Efforts have been made to keep the monitoring going, despite aggressive natural conditions that have affected the sensors. The hydrological monitoring station is expected to serve a crucial role in helping determine and foresee dredging needs in the bay and provide physical environmental variables for the future management of the river and estuary.