Design and Planning Considerations For a Seabed Survey Vera Quinlan Hydrographer & Data Processor Seabed Survey Overview Survey Platform - What boat do I use? Survey Area / depth of water / objective & datasets / time of year Data Collection and Survey Equipment - What equipment for which data set? Bathymetric; MBES (including backscatter) Geological; Pinger / Side Scan / Sparker / Cores Biological and groundtruthing; Grabs, video tow Design and Considerations How do I do it? Survey Plan the key to a successful survey Factors to consider Infomar Data download www.infomar.ie What are the research opportunities? Talk to us! 1
Survey Platform RV Celtic Explorer RV Celtic Voyager 65.5m / 15m / 5.8m 31.4m / 8.5m / 3.8m 16 knots - 45 days endurance / Ocean 10 knots - 14 days endurance / Coastal Mapping from 50 to 7000m! (2015) Mapping from 20 to 400m Qinsy/ Ixsea and Sonardyne USBL / SBP / EM1002/3002/EM2040 / CNAV 3050, Seapath 200/330, ROV, Vibro-piston coring, SeaSpy magnetometer - Edgetech 4200 SSS - Geo-Sparker 200 Liaise AF CV for summer 2015 MBES - MultiBeam Echo Sounder - Sound to measure depth - Swath = ~X8 WD (50m /400m SW) (20m /160m) - Speed CV~8kts Bathymetric data set Positioning <10cm! With PPP (Cnav) PRH seapath 330+ Tidal correction GNSS (CNAV) 15cm vertical SVP (temp salinity sos) up to 1 per hour. Bathymetric Data Collection & Equipment 2
Bathymetric Data Collection & Multibeam Echo Sounder Equipment Teelin Knowl Gascanane sound Cape clear & Sherkin Seafloor backscatter amount of acoustic energy reflected, determines bottom type, mud returns weaker signal than harder rock. Build a substrate map Side Scan Sonar Edgetech Side Scan Value added, in conjunction to MBES - Pro s good additional image, Cons Slower acquisition speed (~4kts), towed, clam sea state. - Consider water depth, obstructions, pots. USES - Object detection, bottom classification, Inspection (not depth) - Wreck analysis / pipeline inspection 3
Geological Dataset - Sub Bottom Profile / Pinger data East West Soft Sediment Bedrock 8 m 250 m Sub bottom profiler collection of sub bottom data geological interpretation - ~20m penetration sediment dependant (CE 2015 ~80m). Biological & Groundtruthing Fisheries UWTV sled - Nephrops Video Ray on mini ROV Day Grab in operation - Defines samples in hard / soft sediment Box Corer soft sediments Holland I 3000m ROV (CE) 4
Seabed Survey Design Considerations - How do I do it? Personnel Collaborate with INFOMAR, project partner Expertise, dongles (Caris / coda / Fledermaus / ArcGIS) Allow budget for contractor (~e400 per day MBES) Processing personel Survey area (overlay admiralty) Admiralty chart - depths, tidal diamond, topography, Shipping lanes, hazards. Harbour master / fishermen - fishing grounds (pots) etc Seafloor topography Lines parallel to contours, (running to coast gives cone effect) less gaps, keep survey lines parallel. Trial and adjust constantly! As u shallow, swath width narrows... - Swath = ~X8 WD (50m /400m SW) Line spacing / direction 10% overlap (line sp = 380m) Weather can be a factor for direction Survey Design Considerations Data Volumes 3 week survey 2TB (10x WCD) Sound speed variations (SVP) Proximity rivers / estuaries Calm summer wx conditions Special Area Conservation? MMO onboard Enclosed bay / estuary, NPWS licence Weather and sea conditions F4... sea conditions rule Survey exposed areas in good wx 5
Survey Design Groundtruth Survey is complete Best practice post survey (to process & interpret BS / MBES / SS data) Groundtruthing Aim to sample ground types Use suite of complimentary techniques; grabs (min 3 per substrate type) video & trawls Plan sample locations Draft constraints of vessel Sample depth (time vs depth) Area 4 X 10km Research Opportunities? Web Mapping Viewer 2014 WWW.INFOMAR.ie Webmapping viewer to display large datasets; Bathymetry / backscatter / seabed classification. Includes data from assoc projects BIM/HabMab etc IWDDS (Interactive Web Data Delivery Service) Download bathy grids / ascii etc. Talk to us!! Benjamin (Coastal Backscatter) / Clodagh Russell MMO Acoustic monitoring Ireland moving towards a MSP (Will Evans) backscatter / create substrate maps / groundtruth & Habitat map 6
WWW.INFOMAR.IE THANK YOU Vera Quinlan INFOMAR Eye of Medusa 7