Concern for Coral Reef Siltation Prompts Researcher to Develop New Strategy for Spill Monitoring

Miami, FL, 2007-10-01 - A new version of SediMeter is now being launched by Lindorm, Inc., as part of a novel methodology for mitigating environmental harm from sediment spill. While the instrument is a visible part of the new strategy, the most significant novelty is in the overall approach. The goals were, improved environmental protection, more cost-effective mitigation, and objective results that can be audited effectively.

The efforts to save beaches by sand replenishment have had the unfortunate side effect of harming nearby hard bottoms through siltation. Siltation refers to an increased concentration of silt in the water, or the accumulation of silt on the bottom (silt is the grain size between clay and sand). While many bottom-living filtering organisms are sensitive to high amounts of silt, corals are among the most sensitive species. This has harmed the Florida coral reef tract, which stretches from north of Palm Beach to beyond Key West.

The SediMeter sensor consists of an array of infrared backscatter detectors. They measure turbidity, which is closely related to the sediment concentration. The array is placed inside a narrow transparent tube, which is mounted so that the lower end is below the seabed. With a detector spacing of 10 mm, and a tube outer diameter of 20 mm, the measurement zones of the backscatter detectors overlap. This makes it possible to interpolate the bottom level with a resolution of 0.1 mm. Both sediment accumulation and increased turbidity are harmful to bottom biota.

The new SediMeter can also measure incident light and pressure. The incident light at the bottom is an essential environmental parameter for the health of sea grass and seaweed, and pressure measurements can be used to estimate wave conditions, apart from measuring the depth as it varies with the tidal cycle.

The new strategy is developed by Dr. Ulf Erlingsson, environmental researcher and consultant. Apart from SediMeters with optimized specifications, it includes software for real-time monitoring of an instrument network, and geostatistical methods for minimizing uncertainty and cost. The existence of this real-time high-resolution monitoring method allows the government for the first time to formulate permits in terms of siltation in sensitive areas around a work zone, rather than in terms of spill leaving the work zone. Imagine a work zone from which the spill during ebb tide is carried off to a mud bottom, but during spring tide is carried towards a coral reef. Does it make sense economically and environmentally to limit the spill equally throughout the day?

A key factor for cost-effectiveness is flexibility. The strategy entails that the government specify the resolution and degree of certainty in the measurement results, rather than how, where, and when to measure. Apart from an alert for too high levels, there is an alert for too much uncertainty, which automatically triggers additional (and costly) ship-based measurements. The project owner is thus motivated to design for the optimal balance between monitoring, measurements, limiting the spill percentage, and scheduling the work.

There is a mutual interest to make sure the data can be audited. The government must be able to make sure that the permit is followed, and the project owner will benefit from data that can stand up to scrutiny in case of a dispute. The SediMeter is equipped with an underwater switch with which a diver can mark the date and time of instrument inspections. This may be used in several ways in an auditable system. Furthermore, for the purpose of data integrity original data files cannot be edited by the user of the system.

While living in Sweden, Erlingsson was senior expert for the government in supervising sediment spill monitoring in a trans-border project with Denmark. He has also worked with spill monitoring. As a young research student he invented the SediMeter, so he knew that there was a technical solution available that was not being used. Erlingsson has also managed a natural hazards project for the Nicaraguan government, which gave him experience in risk management thinking and GIS software development. All of these experiences played a role in developing the new spill monitoring strategy.

About Lindorm, Inc. - Recognizing the need for solutions to save the nearshore environment of Florida and many other coasts, Lindorm was established in 2006 to develop and market ingenious solutions aimed at working in harmony with nature. Lindorm took over the R&D carried out by Erlingsson Sub-Aquatic Surveys (ESAS) since 1989, and has several unique products in its portfolio. The SediMeter was marketed by ESAS until 2006.

Press Room

CEO Ulf Erlingsson, PhD
+1-305 888 0762
info@lindorm.com

All Press Releases

2008-11-03: Sediment instrument for networked environmental monitoring

2008-07-07: Study Suggests Jökulhlaup Behind Dramatic Climate Warming

2008-06-01: Lindorm Delivers Automatic Measurement Station to IAEA Project in Lake Yojoa, Honduras

2008-03-03: First Shipment of SediMeters made in USA

2007-10-01: A new version of SediMeter is now being launched by Lindorm, Inc., as part of a novel methodology for mitigating environmental harm from sediment spill...

2007-07-25: The use of an existing technology could save Florida’s one remaining, near-shore, living coral reef...

2007-03-01: A new SediMeter targeted to the environmental monitoring segment will be released...