Monthly Archives: May 2016

The USACE input in the SediMeter development

Miami 2016-05-18 – The latest SediMeter™ models were developed based on feedback received from the USACE, in order to create an instrument that stands up to the demands of the army corps of engineers in their toughest field deployments.

A few years ago the USACE tested the previous (second) generation SediMeter, SM2, which was developed in 2007. It was a huge improvement over the first commercial generation from the 1990’s, but it was still not tough enough. So based on the feedback from the researchers of the army corps of engineers, we created the specs for the third generation:

It was to be designed to survive the toughest environment where it would be meaningful to deploy it, i.e. a beach with breaking waves. So it must have a minimal cross-section, which meant that we did away with the instrument house — all electronics was made to fit on the sensor board.

Units equipped with a cleaner had to survive continuous use for years in the ocean, why the motor hardware was made of the best possible materials with no concern for cost. And it was tested for years in salt water.

We also eliminated all redundant features. The less things that can go wrong, the more reliable a product is. And we permanently seal them to decrease the risk of water leakage. The version without cleaner is solid state, and the one with cleaner has one moving part: The reel for the line, driven by a shaft that is sealed by three o-rings; and even if all three fail, there is a permanently sealed backup to protect the electronics from water. This third generation of SediMeters, SM3, came out in 2013. By now the design has been field tested and fine tuned for 3 years.

Says the inventor Dr. Ulf Erlingsson: “I spared no effort to make this the best SediMeter money can buy, and I am completely pleased with the result,” adding that there is nothing he wishes he would have done differently, neither in the instrument nor in the measurement system that it forms the heart of.

Rent a SediMeter instrument!

You can now rent a SediMeter instrument for your sediment project, instead of buying. Maybe you have a research project involving measuring sedimentation, erosion, siltation, resuspension, scour, or near-bed turbidity, but you just need the instrument for a few days or maybe a couple of months? In that scenario renting makes economical sense.

Maybe you have been tasked with performing dredging monitoring, supervising sediment spill and making sure it does not accumulate on coral reefs, oyster beds, mussel banks, or in seagrass fields, and you need many instruments but only for a limited time. Here is a plan: Buy one or a few instruments for the background data collection, and to familiarize yourself with the instrument.

Less problems, more data

Then rent a slew of instruments for deployment during the actual works. Why buy them if you only need them a few weeks, right? Let us handle the maintenance, storage, make sure they always have the latest firmware and fresh batteries, and just rent again the next time you need them. It saves you a lot of trouble, and you’ll always have the “latest model”. Just make sure you book in time so that you don’t get without it when you need it.

The SediMeter sediment measurement instrument is now available for rental. We can also offer leasing as an alternative to buying.

The SediMeter sediment measurement instrument is now available for rental. We can also offer leasing as an alternative to buying.

Use the Contact form or call us to make a reservation.

The SediMeter turns 30 years, but where did it come from?

A hundred years ago Physical Geography concerned itself with the description of landforms and processes, and deductions about how these processes had led to those landscapes. Then in the 1930’s a research student in Uppsala called Filip Hjulström crossed the river called Fyrisån every day on his way to the department. He stopped, took a water sample and measured the water level. He then analyzed the sediment concentration and made a quantitative estimation of soil loss through river runoff. Years later he became the professor of the department, and a series of research students dedicated themselves to the quantification of the geomorphological processes: Åke Sundborg (who would succeed him as professor, studied fluvial processes in the river Klarälven), Anders Rapp (who would become professor in Lund, quantified mass transport in the Swedish mountains), John O Norrman (who succeeded Sundborg, studied coastal processes in the lake Vättern), Valter Axelsson (whose homepage is on a “museum domain”, studied delta deposition), and others.

Filip Hjulström (sitting) and Åke Sundborg in 1957.

Filip Hjulström (sitting) and Åke Sundborg in 1957.

To carry out quantitative geomorphological studies frequently requires inventing new instruments and methods. The department got a world-class Geomorphological Laboratory with flumes and a professionally staffed workshop. Valter Axelsson developed a method for quantification of recently deposited sediments using X-ray and the rectangular Axelsson corer. Bengt Nilsson developed a suspended sediment sampler for vertical integrated suspended sediment sampling, during the International Hydrological Decade. The sampler was widely used especially in remote parts of the world, and it is still available for purchase – even though it will soon turn 50 years!

Valter Axelsson in the Cachí Reservoir, Costa Rica, putting his quantitative X-ray based method of estimating sediment bulk density to good use.

Valter Axelsson in the Cachí Reservoir, Costa Rica, putting his quantitative X-ray based method of estimating sediment bulk density to good use (1989).

I was lucky enough to have Rapp as professor during my undergraduate years in Lund University, and to then come to Uppsala University for my PhD studies. Having access to the Geomorphological Laboratory and the workshop I was able to develop the SediMeter. The purpose of the instrument in my thesis was to determine the onset of bedload transport on nearshore bottoms, and to find out what happens off the “closing depth”. However, already during the initial field trials in 1986 (under the ice of a frozen lake; working near the Arctic Circle does tend to limit the time available for field testing) I found that the instrument had potential applications that went far beyond those initially contemplated.

Bengt Nilsson (left) and Ulf Erlingsson (author) in Örserumsviken, Västervik, Sweden, 1999.

Bengt Nilsson (left) and Ulf Erlingsson (author) in Örserumsviken, Västervik, Sweden, 1999.

Since my career took a different path I didn’t continue using the instrument until I decided in 2007 to develop a new, better version. That second generation was again replaced by a third generation in 2013. Electronics have developed tremendously, but the basic design of the sensor has stayed the same, because it works so well.

We now write 2016 and 30 years has passed since the first field deployment of the SediMeter. It has developed into the world’s arguably best system for monitoring siltation caused by sediment spill and pollution from dredging and other works. It is also used to monitoring sedimentation in reservoirs, harbors, and navigation channels, and in laboratory experiments, as well as for monitoring resuspension and erosion.

The Geomorphological Laboratory is, alas, gone, and the Department of Physical Geography has been merged and reorganized, but a number of instruments and samplers developed in the Uppsala School of Physical Geography live on as commercial products – and the SediMeter is one of them.

Written by Ulf Erlingsson

SediLink radio modem on a SediMeter

The SediLink radio modem can be mounted directly on a SediMeter SM3A for lab use. This is useful for instance in a physical model of an engineering project where the objective is to study sediment transport. Later the same equipment can be used to verify the predictions in the field, but with an extension cable between the SediMeter and the radio modem—and a buoy so it gets up above the water surface!

A SediLink radio modem mounted directly on a SediMeter

A SediLink radio modem mounted directly on a SediMeter

Preparing the SM3B for deployment

To prepare the SediMeter™ with cleaner for deployment take note of the following advice:

The cleaning shuttle has to be positioned at the top of the sensor, near the motor house, for the cleaning operation to be carried out correctly. If it is placed too low, the instrument will report an error at the end of the first cleaning, and will then turn off any further cleanings.

If you wish to test the cleaner, please be advised that the instrument will only execute a cleaning if it is able to determine the level of the bottom. This means that the instrument must be in water and with at least the lowermost detector covered by something that gives a significant signal (sediment, or a piece of paper).

Also, there must not be any strong signal higher up, because if the SediMeter™ cannot determine with certainty where the bottom is, it will err on the safe side and not carry out the cleaning. This is to avoid running the cleaner into the bottom since that would entangle the line.

As for settings, the Next Wiping should be set so high that there is time to deploy the instrument before the cleaning is due. This is because in case of error, the cleanings will be shut off for the remainder of the mission. So make sure not to order the first cleaning before the instrument is deployed in the field.

New SediMeter™ Flyers

A new section has been added to the Downloads page with pdf flyers outlining the products and services related to the SediMeter™ for the benefit of those who prefer to read from paper rather than from a computer screen. Here is an example:

SediMeter™ Custom Solutions flyer

SediMeter™ Monitoring Solution flyer

Lindorm Blog

The website of Lindorm now incorporates a WordPress blog. It will be used to publish press releases, application examples, and other more dynamic information, using categories to organize them.

When overhauling the website we have also rearranged the information on most pages, replacing wide columns with narrower columns so that it will be easier to read on a narrow screen (i.e., cell phone). But we don’t plan to completely eliminate the need to scroll left and right, since unlike Google we think our visitors are perfectly able to do that (Google thinks that you guys are only capable of scrolling up and down).