Real-time monitoring of endangered freshwater mussels in the Ohio River is helping the US Army Corps of Engineers to protect the shellfish during dredging.
The Ohio River is the largest tributary, by volume, of the Mississippi River. Running westward from Pittsburgh, Pennsylvania to Cairo, Illinois, the river is home to various species of freshwater mussels. These mussels not only provide a crucial food source for the muskrats, waterfowl and fish that inhabit the river, but also provide important water-quality indicators.
Given the capacity of bivalves such as clams and mussels to clean up chemicals, control nutrients and restrict the build-up of algae, as highlighted in a recent Stanford University research report, any reduction in the Ohio River freshwater mussel population could presumably have a detrimental effect on the quality of its water.
Mussels dread dredging
At the Robert C. Byrd (RCB) Locks and Dam, located on the border of Ohio and West Virginia, however, a dredging project begun by the US Army Corps of Engineers in October 2016 threatened to disrupt the ambient environmental conditions needed for the mussel population to survive.
The RCB consists of four locks: one for commercial barge traffic that is 1,200 feet long by 110 feet wide; an auxiliary lock that is 600 feet long by 110 feet wide; and two smaller parallel locks. As the locks are navigable by boat, each of them requires dredging operations – or clearing of the river beds – to keep the channels open and operable, creating an average of nearly 90,000 cubic yards of dredging material annually.
With the presence of endangered mussels, the process of dredging requires continuous scrutiny in order to avoid harming the population further. To monitor and minimize the effects of any dredging activity, the mussels have come under the protection of the Wizard platform from West Virginian engineering company Aridea Solutions and Spanish wireless devices manufacturer Libelium.
No magic, just data
Wizard, a joint development from Aridea and Libelium, stands for Water Intrinsic Zoological Ambient Research Device. The platform connects sensors to Aridea’s Terralytix Edge Buoy, a solar-powered communications buoy that integrates Libelium’s Waspmote Sensor Platform to record and send data, such as water depth and quality, conductivity, pH, turbidity and dissolved oxygen levels.
The buoy is also equipped with a Transducer Array from high-frequency acoustic instrumentation company, SeaTek, to monitor the build-up and depth of any sediment through an ultrasonic ranging system.
All of the data generated is sent directly from the Waspmote Sensor Platform to Aridea’s Terralytix Portal at five-minute intervals via a 4G connection. From here, members of the US Army Corps can collect and aggregate the data using a single interface.
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Saving costs while saving mussels
Supposedly, the Wizard platform is capable of being deployed from a boat, without divers, up to depths of around 20 meters of water. As a result, it has enabled the US Army Corps of Engineers to wirelessly obtain data from the bottom of the Ohio River during active dredging.
In addition, the Army Corps is also said to be using the RCB Locks and Dam differently now, by steering the currents created by alternative gate operations to direct sediment away from the mussel beds and thus reducing danger to the mussel population.
“These innovations have been well received by our partners in other state and federal resource agencies and have allowed the district to continue cost effective in-water disposal operations,” said Steve Foster, a limnologist (the term for someone who studies inland waters) at the US Army Corps of Engineers.
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