Department of Fisheries and Oceans / ASL Environmental Sciences Limited

FPTT Technology Transfer Award

Department of Fisheries and Oceans/
ASL Environmental Sciences Limited

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Successful transfer and commercialization of a space-time acoustic scintillation technique for the measurement of water flow

David Farmer
Institute of Ocean Sciences, DFO

David Lemon
ASL Environmental Sciences Limited

Perseverance, resourcefulness and patience are three virtues that often turn a simple act of faith into a successful transfer of technology. Dr. David Farmer, a research scientist with DFO in Sidney, British Columbia and ASL Environmental Sciences Ltd., displayed an abundance of all three in their decade-long quest to bring a breakthrough procedure to measure the flow of water into widespread commercial use. Known as the space-time acoustic scintillation technique, the method exploits the way in which sound pulses transmitted from one point and measured at other points are modified by such natural variability in the water. Theoretical techniques are available to allow inversion of the results so as to provide accurate measurement of water properties such as currents, temperature variability and turbulence. Invented by Dr. Farmer and his colleague Dr. Clifford in 1982 and subsequently developed collaboratively with Mr. Lemon of ASL, the technique has an impressive range of applications that span the measurement of ocean currents to the load tuning of turbines for improving efficiency of hydroelectric energy production. Sales of $450,000 in 1998 represented 30 per cent of ASL's activities, a percentage of which goes back to DFO through licensing revenues allowing for further research.

Scientific credibility of the underlying technique was supported and enhanced through publication in scientific journals of numerous papers on the technique and its application, together with international recognition expressed through awards received for development and use of acoustical methods. The impact on Canadian prestige through world-wide recognition of scientific expertise in federal laboratories is extremely important for Canadians. In fact, Dr. Farmer was selected recently to participate on the scientific planning committee for the Census of Fishes - a new international project initiated by the Sloan Foundation, with the goal of adding to our knowledge of life in the world oceans. The initiative is expected to be global in extent and it is hoped will attract extensive support from national and international sources over the next 10 years.

Development of the measurement system posed numerous technical and financial challenges. With little or no funding in the early stages, Dr. Farmer used scavenged surplus components to build a prototype system that he tested from a towed barge. Following these early tests, he and his colleagues searched for a comprehensive theoretical and technical basis for the method, including optimum signal processing, array geometry, frequencies and data interpretation. Graduate students from the University of Victoria played an important role in all stages of the development.

Early versions of the instrument generated massive data sets, requiring tape changes every 10 minutes day and night and enormous processing efforts by the students later on. Funding from the Canadian Panel of Energy Research & Development, with support from the US Office of Naval Research, allowed ASL, the B.C.-based manufacturer and licensee, to implement powerful real-time signal processing using a novel hard-wired correlator engine they developed especially for the purpose. Since then, the system has been refined and the range of potential applications greatly increased. ASL has now implemented the technology for DFO in a variety of coastal environments. With a US company, they developed a battery-powered version that was successfully used in the Black Sea in Turkey. A recent contract will lead to provision of real-time navigation information in Vancouver Harbour. Prominent customers in the hydroelectric field include the U.S. Army Corps of Engineers and the Tennessee Valley Authority. Most of the sales are in the US export market and the superiority of this technique over competing methods is now recognized by both American and Canadian utilities.

Sponsored by:
Borden Elliot Scott & Aylen