FIELDWORK AT TEIGNMOUTH, UK Overview of the characteristics of the May 2003 Campaign (Phase II 12/05/03 – 30/05/03)

CONTENTS Site characteristics Objectives of the field campaign Coastal State Indicators & field data needs Comparison of data collected (Phase I vs Phase II) (how, where, main variables, main results) –Morphology measurements –Shoreline surveying –ADCP measurements (currents and waves). –SLOT data (waves, currents, and sediment transport) Summary

SITE CHARACTERISTICS Complex system of multiple bars –Long-term cycle (5-8 years) Sediment movement Sandbar movement cause: –Navigational problems –Recreational hazards –Governs sediment budget on the beach (affecting the structural stability of seawall) slot

OBJECTIVES Provide “ground truth” for validation and development of video-derived CSIs –Provide in-depth understanding of the morphological cycle (video) and the associated (short term) sediment transport processes (SLOT). Show data availability and methods of collection to partners

CSI FIELD DATA MATRIX SLOT dataSystem classification ADCP (directional waves) Directional wave spectra ADCP (currents)Location of dredging Shoreline surveying Location of channel markers Beach morphology Surface currents Bathymetric surveysBreaking wave patterns (2D) Intertidal mapping (3D) Subtidal mapping (3D) Field data needsVideo-derived CSIs Coastal Management Issues Video-derived CSIs Field data

MORPHOLOGICAL SURVEYS Rational –Ground truth for Video - CSIs Breaking wave patterns (2D) Intertidal mapping (3D) Subtidal mapping (3D) Location of dredging System Classification

MORPHOLOGICAL SURVEYS How? –Kinematic DGPS mounted on quad-bike or boat (+ echosounder) & land-based station May (2003) 26 Nov – 10 Dec 2002

May 2003 (Phase II) 4 Quad-bike surveys 3 Boat surveys MORPHOLOGICAL SURVEYS Nov- Dec 2002 (Phase I) 6 Quad-bike surveys 3 Boat surveys Where and how many tracks

SHORELINE SURVEYING Rational –Ground truth for Video–derived Intertidal mapping Assess shoreline variability in time and space (swash) Related with wave energy level (In which way?) Estimate errors in video-derived shoreline detection

Problems: –Difficult to operate –Cannot resolve shoreline variability (space and time) May 2003 Trinocular video system on the beach –Resolves elevations (z) and variability in time. –12.5 hr footage sampled at 1 Hz. SHORELINE SURVEYING November 2002 Hand-held DGPS following shoreline + compare with rapid sampling BACK

SHORELINE SURVEYING (Trinocular video) 3 video cameras Data cabled to a car- based PC Looking at a delimited area on the beach GCPs and cameras regularly surveyed (with style) with total station

3D CURRENTS IN CHANNEL (ADCP) Rational –Surface currents in channel Can we identify the channel through current structure Intensity of currents at channel –Surface currents elsewhere Can rip currents be identified

November 2002 Not performed May 2003 Collaboration with University of Cantabria (ADCP) Problems: –Need to remain stationary (no bottom tracking) Current measurements in the channel in June with bottom tracking ADCP. 3D CURRENTS IN CHANNEL (ADCP)

WAVE DIRECTIONAL SPECTRUM (ADCP) Rational –Directional wave climate offshore (CSI)

WAVE DIRECTIONAL SPECTRUM (ADCP) Where and How: –ADCP mounted in a steel frame –Deployed by boat at 4-5 m depth offshore from the Ness Headland

WAVE DIRECTIONAL SPECTRUM (ADCP) November days of data (every 30 min) May days of data (every 30 min)

SHORT-TERM PROCESSES (SLOT) Rationale –Understanding the sediment transport mechanisms important for the long term morphological changes (Robinson’s cycle)

SHORT-TERM PROCESSES (SLOT) Onshore migration of sandbanks in the vicinity of coastal inlets is a very common phenomena. Kennebeck River, Maine, USAWadden Sea Inlets, NL

May SLOTs in 4 different position at offshore sandbank only 18 tides of data at 4 Hz SHORT-TERM PROCESSES (SLOT) November SLOT systems in 5 different positions. Shore attached bar and adjacent beach 65 tides of data at 2 Hz Which variables, where and when –OBS (suspended sediments), EMCM (horizontal currents), PT (surface elevation), installed at the low water mark. SEAWALL Pier SLOT S

V

SLOT 3 ON CREST OF SHORE-ATTACHED BAR

STORM PEAK ON 10 DECEMBER

SUMMARY Field data needsNov – Dec 2002May 2003Future Bathymetric surveys Beach morphology Shoreline surveying  ? ADCP (currents)  ? ADCP (directional waves)  SLOT data ? All this data is now available on the server

SHORT-TERM PROCESSES (SLOT) BACK

SHORT-TERM PROCESSES (SLOT) System state on May 2003 (from seawall) System state on May 2003 (from pier) BACK

Phase I Morphological Surveys Nov – Dec 2002 Quad-bike surveys Boat surveys BACK

Phase II Morphological Surveys May 2003 Quad-bike surveys Boat surveys BACK