Monthly Archives: March 2007

New SediMeter Under Development

Miami, FL, 2007-03-01 – A new SediMeter targeted to the environmental monitoring segment will be released by Lindorm, Inc., later this year. The instrument has been on the market for years in a version aimed primarily for marine researchers.

The new version has been developed in response to a concrete demand in Florida. When officials from the Florida Department of Environmental Protection, who needed an instrument to monitor siltation on coral reefs, met with the inventor of the SediMeter, the two parties realized that a SediMeter with suitable specifications was just what they needed. Since then Lindorm put the testing of the Wave Engulfer on hold and focused completely on the SediMeter.

The problem that prompted this new version is caused by beach nourishment in Florida. In order to save the eroding beaches, and the infrastructure behind them, the state is dredging sand on the continental shelf and placing it on the beach. However, some fine material, also known as silt, may be present in the sand, which causes the water to be cloudy when waves stir up the sand. This turbidity damages the hardbottom communities off the beach, and it has killed most of the nearshore coral reefs.

The SediMeter can be used to measure both the deposition of silt on the hardbottoms, and the turbidity level just above the bottom where the corals live. The instrument can be operated either as a stnad-alone logger, or connected in a network to a computer on land. In the latter configuration it can be used to give real-time warning of high silt levels, so that the activity doing the harm can be decreased or stopped until the weather and tides become more favourable.

Apart from saving the environment the SediMeter can also save money since it can be used to show that no harmful conditions are present, if that is the case. Using a network of recording instruments before, during, and after a project is a convenient way to collect proof that no harm was caused by an activity, thus avoiding potential future liability.

The patented sensor consists of a vertical array of overlapping optical backscatter detectors. By interpolating the turbidity measured by each one of them the level of the bottom can be determined with a resolution of 0.1 mm or better. The instrument was invented by Ulf Erlingsson while working on a research project at Uppsala University, Sweden, in the 1980’s. The purpose was to detect how the bottom morphology changed with time in an area with sand ripples, and the research project dealt with sand transport on inner continental shelves.

The new version, known as Model 2, will be manufactured in the US, and the price will be cut by half compared to the previous version. Virtually every aspect of the design has been improved; it is smaller, tougher, more precise, with more memory, using less battery, with a longer sensor, and with new options such as pressure and light meter.