Company

STEMA is an independent company providing services for national and international customers. We develop software and instruments for geophysical applications and provide services in hydrographic and geodetic marine survey projects. The service activities include hydrographic, geodetic and geophysical surveys for a variety of user groups in dredging and civil engineering companies, port authorities, consultancy firms, the oil and gas industry, as well as various governmental bodies both in The Netherlands and overseas.

The operational activities cover a wide scope of professional disciplines: hydrographic surveys for dredging operations, typically pre- and postdredge situations, silt measurement and turbidity monitoring during dredging, pipeline and cable route surveys, marine deposit exploration as well as dedicated positioning services.

STEMA has developed SILAS software and DensiTune insertion density meter for determination of the stratification and characterisation of the seabed sediment and density distribution in marine silt deposits for dredging and management purposes. For defining the in situ density of siltlayers STEMA has built the STEMA DensiTune silt density probe, which is capable of measuring online absolute density and viscosity values. By importing the in situ density profiles into the seismic files of the SILAS software, survey organisations are able to measure and chart density layers area covering.

Late applications of the SILAS software include pipeline inspection surveys, site investigation for the determination of sediment characteristics, marine aggregates like sand and gravel, bedrock level and overburden. Recently the SILAS software has been used with conventional dual frequency hydrographic echosounders and gives remarkable results. In this way the echosounder is converted into a system with the capabilities of a subbottom profiler. The system is increasingly being deployed for the assessment of silt layers and pollution on ports, rivers and coastal waters.

The service activity of STEMA is consultancy, planning and organization of survey activities, sea as well as land born. We in particular assists our Clients to define their requirements into survey methods and quality procedures. Examples include construction projects as Storebelt West Bridge Project in Denmark, Second Tagus Bridge Crossing in Lisbon, Lehrter Bahnhof Los 1.1 Project in Berlin, LNG Terminal Project in Trinidad and Bridge Construction Project Surinam and Coppenam Rivers.

We, at STEMA. can offer you solutions for a wide variety of survey services.