Underwater Geophysical Survey, Lac St. Pierre, Quebec
NOTRA was contracted by CH2M Hill to conduct a 100% underwater geophysical survey and interpretation assessment in the Nicolet River (approx. 36 hectares) and Landroche Channel (approx. 11 hectares) near the City of Nicolet, Quebec.
Specifically, NOTRA was responsible for:
- Reviewing and commenting on the Geophysical survey plan;
- Mobilizing and demobilizing all necessary personnel and equipment to carry out the geophysical survey;
- Establishing an underwater test area (UTA) and testing the equipment to be employed on the project in the UTA on a daily basis;
- Conducting the underwater survey using an array of three submersible time domain electromagnetic metal detectors to collect data. The array was connected to a controller laptop through cables and to the tow platform by a constant length tether system. Data was collected at a rate of 10 per second and the maximum speed of operation was under 4km/hr. Positioning of the data was accomplished using Real-Time Kinematic (RTK) Global Positioning Systems (GPS) for the highest accuracy GPS positioning available. The tow platform consisted of a flat bottom boat and zodiacs were used in support of the operations;
- Providing all qualified personnel, equipment and supplies to carry out intrusive dive investigation;
- Reacquiring target anomalies using a combination of GPS technologies and underwater hand held metal detectors;
- Investigating the targets to a point where it could be positively identified as UXO (or other hazardous items);
- Providing on-site management during operations; and
- Completing daily reports and ftp postings.
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