When Ulf Erlingsson invented the SediMeter™ for his doctoral dissertation in 1985, the goal was to detect incipient sediment motion on the bottom of the sea, so as to compare that with wave and current data to see what combination of processes led to the initiation of sediment transport for different grainsizes, waves, and currents. The question was how to define sediment transport, but once the SediMeter was invented, it became a non-issue: The instrument is capable of detecting the difference that a single grain of sand makes in front of the sensor, and it is stable enough to give the same value when nothing changes. Thus, the definition became “what the instrument can detect,” and that was pretty much anything that happened to the sediments.
Fast forward to the 1990’s, and now Dr. Erlingsson was hired as an expert in sediment spill monitoring by the Swedish government, during the building of the Öresund bridge and tunnel between Sweden and Denmark, and the dredging of a new navigation channel to the Baltic Sea. Seeing this ambitious project from the front seat, from the regulator’s perspective with full insight into the executor’s monitoring and analysis, he became convinced that it would be more cost-effective, and wise, to use a monitoring system of stationary SediMeters™ in a real-time network, monitoring the sediment accumulation and near-bed turbidity directly, and to connect permit conditions to the sensitivity of each biotope.
When Erlingsson in 2006 got an opportunity to manufacture the SediMeter™ instrument himself, he decided to create “the best siltation monitoring system in the world,” based on his experience from the Öresund project. Since he by then lived in Miami, he designed it with the purpose of monitoring hard bottoms—including coral reefs—when there were dredging operations going on nearby. His new version of the SediMeter™ that came out in 2007 was designed specifically for the requirements identified in the siltation monitoring white-paper.
Since the only transparent anti-fouling paint on the market was banned a few years back, he next had to develop a new method for keeping the sensor clean from biofouling. In 2013 he released the third generation SediMeter™, with exactly the same proven sensor, but with a mechanical cleaner integrated in the instrument from the outset (it is also offered without cleaner). It has no logger house at all, since everything has been made to fit on the half inch wide sensor PCB.
Next Dr. Erlingsson turned his attention to wireless networking. All SediMeters™ made in Miami can be networked using RS485, which allows for mile long cables, but cables cost money. After several semi-custom solutions, in 2015 he developed the SediLink™ radio modem with a built-in small solar panel that can sit on a buoy over a single or a few SediMeters™. This allows for mixed networks with radio links and cables. The radio modem has a socket for a radio that the customer himself can mount, meaning that wherever in the world the client is, there is a license-free radio available.
The SediMeter™, its program and network abilities were developed to fit the role of a siltation monitoring system, which was formulated based on experiences from the most ambitious sedimentation monitoring project in the world. That is why Dr. Erlingsson does not hesitate to say that in his opinion, his design is the best siltation monitoring system in the world.