Continuous Instream Monitoring

Turbidity in natural waters is recognized as an important indicator of its environmental health, and because it's a good surrogate for suspended sediment, monitoring turbidity has always been the "holy grail" for hydrologists. But because of earlier technology, "turbidity" has traditionally been a "bad word". The DTS-12 turbidity sensor is the first sensor to make turbidity monitoring practical, and no longer difficult, inaccurate, expensive, or labor-intensive. Turbidity is the cloudiness or murkiness of water caused by suspended organic or inorganic materials. Turbidity in natural waters is recognized as an important indicator of its environmental health.

  • Turbidity can be a good indication of impairments such as nutrients and e-coli, and is an excellent surrogate for suspended sediment concentration.
  • Fish habitat is impacted by turbidity. Suspended particles absorb sunlight, raising the temperature of water which causes oxygen concentration to fall. Poor visibility also impedes feeding.
  • Monitoring turbidity in a watershed permits preemptive response to water quality events which could otherwise put the public health in jeopardy. FTS' systems can be configured with flexible early warning detection capabilities to fire alarms via email or SMS messaging upon one or more conditions being met.
  • Enables regulatory and compliance monitoring of NTU thresholds, TMDLs and BMPs.
  • Permits monitoring impacts of land development and resource extraction, including adherence to the EPA’s new standards controlling the discharge of pollutants from construction sites.
  • Provides easy detection of contaminants due to stormwater runoff.
  • Turbidity is very useful for triggering strategic, event-based automated sampling. Unlike stage or other measurements, an increase in turbidity is definitely indicative of an issue that should be sampled. Our SedEvent™ system is designed around this concept of turbidity threshold sampling.
  • Continuous monitoring of turbidity captures far more temporal data to provide a far better characterization of turbidity changes over time than manual grab sampling.

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The USGS team provides their online users with access to real-time data about the streamflow statistics and basin characteristics throughout the waterways of Arkansas. Anglers, boaters, water-resource managers, and anyone requiring current data about the water flowing through the streams of Arkansas, turn to the web to obtain useful information including stage, streamflow, turbidity, temperature, and pH.

Some of the streams, especially those within the Ozark Forest on the Missouri border, are extremely remote and require a three hour drive to get to the site. Once at the site, the team needs to collect the samples taken by the ISCO autosampler, restock as needed, and ensure the equipment is operating correctly. Since the autosampler has a finite number of containers, the team needs to ensure the unit is stocked regularly, but need to minimize unnecessary site visits. Also, since the ISCO sampler does not natively support being controlled as an SDI-12 device, the team was unable to transmit the container status via GOES. This resulted in unnecessary site visits with containers still available in the sampler, or missed samples when no empty containers were present.

The USGS team contacted FTS to find a system that would work well for their situation. The FTS team suggested that an Axiom H2 Datalogger (DCP) could be connected directly to the ISCO sampler utilizing an Autosampler Interface Controller, allowing communication via SDI-12. The bottle status would then be able to be transmitted via GOES, updating the team hourly as to how many empty containers are available to collect samples.

The installation revealed no surprises, and the equipment continues to work exactly the way the team needs for their six locations. They’re now confident in their ability to collect water quality information to establish baseline data for the creeks and streams they’re responsible for.