Marina dredging with DOP150

In the tidal lagoon south-east of Cadiz, southern Spain, is the yachting marina San Fernando. Over the past few decades the access to the yachting harbour “Club Náutico de la Casería” and its berths have silted up heavily due to tidal and river flows carrying silt into the harbour. To ensure access for the pleasure yachts and small fishing vessels, major dredging activities have been required. For the job, an amphibious excavator with a DOP150 is being used.

Compact submersible dredge pump

The location is easily accessible with practical access to the marina using a boat ramp. The contractor’s amphibious excavator was equipped on site with the DOP150 submersible dredge pump with the assistance of a Damen Field Service Engineer. The hydraulically driven dredge pump has been fitted out with a cutter unit, which loosens the soil and so improves the dredging process. The DOP pump is part of a complete dredge package which includes the submersible pump, the exchangeable drag head, a discharge hose with floats and start-up assistance.

A challenging dredge project

The job itself seemed obvious: pumping out some 19.000 m³ of silt and caked mud to a spoil field nearby. The DOP pump works at a dredging depth of max -2 metres to -4 metres, using a 200 mm discharge pipe line of some 500 metres length, which partly floats in the harbour before the slurry reaches the storage area further along the coast.

The main challenge is in the pollution found in the silt layer. Over the years ropes, plastic and other debris, have washed up in the marina, and become trapped in the sediment. Due to the large sphere passage of the DOP dredge pump is able to handle items such as stones etc. However, the debris cakes together around the suction head, causing the crew to stop regularly to remove the material, before starting the next dredging stretch.

The result of the dredging campaign will be that the marina will be accessible at low tide, boosting local activities and the economy.