The Department of Transport, Tourism and Sport (DTTAS) advises that TechWorks Marine has deployed four trawl-resistant, bottom-mounted Acoustic Doppler Current Profilers (ADCPs) frames throughout Lough Swilly.
The frames deployed on Wednesday 20 February will be on the seafloor for a minimum period of one calendar month and a maximum period of two months (weather permitting).
Water sampling surveys are required to be carried out at the same time as the deployments and these are tide and weather dependent, and may cause a slight delay in recovery, hence the two-month deployment period.
The ADCPs will be measuring currents through the water column at each location over the month-long deployment. This data will be used to validate a hydrodynamic model of the area being developed for Irish Water.
The deployment locations as noted in Marine Notice No 5 of 2019 are (degrees, minutes, seconds) WGS84 as follows:
- ADCP 1: 55° 12' 59.5" N, 7° 34' 37.2" W
- ADCP 2: 55° 06' 51.9" N, 7° 29' 02.7" W
- ADCP 3: 55° 03' 52.4" N, 7° 32' 11.3" W
- ADCP 4: 55° 01' 17.5" N, 7° 32' 55.4" W
Each frame will have an ADCP sensor (for waves and currents), acoustic release, rigid recovery buoy, acoustic pinger and grapple line. The frames are approximately 1m2 and will remain on the seafloor for a period of up to 30 days, after which the frame will be retrieved by the acoustic release by the retrieval team of a pop-up buoy allowing for its recovery or by a grapple line recovery method.
During the extent of the deployment, ADCP frames 1, 2 and 3 will have a surface marker. The ADCP 1 and 2 will have a red in colour surface buoy and ADCP 3 will have a yellow in colour surface buoy. There will be no surface marker for ADCP 4 so vessel traffic will not need to avoid its location but should be aware of its presence.
