INTRODUCTION

The main body of the data collection programme occurred over the period January to March 1999 although some elements such as the video monitoring of the new inlet at the Praia de Faro began much earlier. LINK TO VIDEO IMAGES PAGE The images shown in these pages are just a selection of some 1700 images taken during the main fieldwork period. Although the following descriptions are aimed at being informative they are by no means the complete story. Questions relating to them or the fieldwork that was undertaken may be directed to Steve Shayler at the British Oceanographic Data Centre on sash@ccms.ac.uk who will try to answer them as best he can.

(Click on any of the thumbnails below to see an enlarged images. To return to the main page use the "back" button.)

17th January 1999: View of the new inlet looking towards Barretta prior to the jack-up barge moving into the inlet entrance.

View of the new inlet looking from Barretta towards the Praia de Faro with the jack-up barge on the Barretta side of the main channel within the inlet entrance.

Left - View from the barge gantry tower at around low water showing the intertidal area around the Praia de Faro side of the inlet mouth on 25th January 1999. Right - Similar view from the barge gantry tower during the flooding tide on the same day.

Left - View of the jack-up barge. This could raise and lower its' corner legs allowing it to move position when required under calm conditions (middle photo). Right - Bird's eye view of the barge deck area showing the investigating scientists hard at work !

Deployment of an Acoustic Doppler Current Profiler (ADCP) in upwards looking mode from the side of the barge.

The POL Instrument Package (PIP) with various instruments prior to deployment (left). Typical instruments used on the PIP included OBSs, ABSs, Sand Ripple Profiler, Sand Ripple Imager, Sontek ADV, Nortek ADV, Laser In Situ Scattering and Transmissometer (LISST), High Resolution Coherent Doppler Current Profiler, 2 x EM Current Meters and a Pressure Transducer. The PIP is deployed through the moon pool on the barge (left) into the water (right).

Using siphons on the PIP, pump sampling from 7 non-linear heights above the bed enabled suspended sediment samples to be collected for analysis to determine suspended grain size spectra and sediment concentrations under different flow regimes. Visually, the water column tended to be more turbid during ebb tide flow conditions.

Left - Woods Hole Institute of Oceanography (WHOI) team members carrying out an ADCP survey within the new inlet mouth. Right - close up of the boat mounted ADCP used in the surveys of the lagoon areas.

Bedforms easily seen through the overlying clear water to the rear of the inlet mouth.

BEACH WORK

METEOROLOGICAL AND AOLIAN TRANSPORT MEASUREMENTS

One of three meteorology data collecting masts deployed on the beach measuring wind speed and direction at heights above the ground, temperature and relative humidity. Two of the masts were fixed to measure meteorological variables at the beach/dune interface and at the heighest point within the dunes. The third mast was mobile so that measurements could be made over the beach area (right) when aolian processes were operating.

Left - A solarimeter used to measure the amount of solar radiation incident on the beach. Right - A sonic anemometer used to measure wind speed and direction in 3D to study turbulence. This also had the potential to measure heat and humidity flux in 3D.

Left - Setting out sabajophones used to measure aolian transport at different heights above the surface. Middle - A close up view of a sabajophone. Right - A saltiphone deployed to measure aolian sand transport. Grain "hits" are registered inside the tube by a sensitive microphone and relayed to a data logger.

Left - Erosion pin transects were used to evaluate variation in surface height in relation to aolian processes over the beach/dune area with time. Centre - Sand traps were used to measure quantity and size of grains transported at various heights above the ground surface by the wind. Right - Dutch team members collecting samples for soil moisture analysis.

BEACH AND NEARSHORE PROCESS INVESTIGATIONS

A number of beach and nearshore investigations were carried out by the University of the Algarve (UA), University of Bordeaux (UB) and the University of Liverpool (UL). These activities encompassed sediment tracer studies, wave run up, hydrodynamics within the surf zone and beach topography. 

Left - Setting up a "goal post" system which has an Electro-Magnetic Current Meter (EMCM) and four Optical Back Scatter (OBS) sensors attached to it at four heights above the beach surface. To the right of the goal post a patch of surface sand (2 x 2m) was removed and replaced with coloured sand to enable it to be distinguished from the normal beach sand so that it may be traced when transported by water action. Centre - Filling the tracer pit with fluorescent orange coloured sand so that sediment transport can be investigated. Right - UA survey team carrying out a survey of the beach area to establish topography of the beach area under investigation.

Left - Part of the UB transect showing an Acoustic Doppler Velocimeter (ADV - in centre) with Pressure Transducers (PTs) in the fore and background. When submerged the instrument allows simultaneous measurement of three components of velocity. Right - A UB team member surveys in the transect.

The UL beach crawler without instrumentation. Moving on caterpillar tracks, it can be fitted with a range of instruments to measure hydrodynamic and sediment transport processes under water. It has a potential maximum range of 500m and is controlled by an operator via an umbilical cord.

REMOTE SENSING

The University of Plymouth has been operating a video tower on Barretta for some previous to the main fieldwork campaign which monitors the inlet mouth and adjacent coastline to the west. This captures images from two video cameras every hour on the hour and provides the following: (1) A "snapshot" image, (2) A 10-minute average timelapse image and (3) A time stacked image. All these produce approximately 50 daily images during daylight. Images have been georeferenced enabling accurate distances to be extrapolated from the images. The visual record produced is an extremely valuable resource enabling the evolution of the inlet to be studied. The end of the video data exercise is scheduled for March 2000.

Left - the X-band radar antennae mounted on the barge gantry tower which captured wave data immediately in front of the inlet. This was set to capture data at hourly intervals. The X-band system has a working range of between 1.5 - 2 km and operates at 10GHz. An example display of X-band radar data output is shown on the right image. The data output allows sequential monitoring of the wave climate and observation of wave advance.

Views of COSRAD (left - Praia de Faro; middle - Barretta by the video tower) and the control/data acquisition equipment (right). This radar system works as a synchronised pair of transmitting and receiving stations with a range of 1 km transmitting at 150 Mhz. It has a spatial resolution of 100m and can resolve surface currents to +/- 1.25 cm/s.

The Ocean Surface Current Radar (OSCR) master site deployed near Vilamoura to the north of Praia de Faro. This received transmitted data from a slave site situated at the Praia de Faro site (shown below). The nominal range of the system is 44 km and transmits in the band 25 - 50 MHz.

The OSCR slave site on the Praia de Faro. The first image (left) shows the transmitting arraywhich consists of 16 transmitters and the second image shows the receiving array which relays the signals to processing and relay equipment in the trailer shown in the background. This then transmits the data to the master site near Vilamoura.

GENERAL VIEWS OF THE FIELD CAMPAIGN

The following images were taken over the main fieldwork period between January to early March 1999 within the Ria Formosa National park on the Algarve, Portugal. They depict some of the processes at work over the period as well as some of the scientific work carried out in the region.

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Image No.1 -    View of Barretta on 17th January from the Praia de Faro side on an ebbing tide. Note the video recording tower on Barretta which takes time-series images                             of the inlet and adjacent coastal areas.

Image No.2 -     The jack-up barge alongside Faro docks being prepared prior to moving out to the inlet entrance site.

Image No.3 -     Team members from the University of Algarve digging a trench for laying communication cables connected to instruments deployed in the surf zone on 20th January.

Image No.4 -     View of the lagoon area towards Faro from the fieldsite at low tide. Note the bedforms on the exposed sandflats.

Image No.5 -     The jack-up barge under tow on 21 January. The barge can move at 1 knot under its' own power but required a tug due to the strong tidal currents.

Image No.6 -     The jack-up barge awaiting a favourable tide to take it into the inlet entrance. Such time was spent organising instrumentation and equipment. The man below the barge                             is testing the POL Instrument Platform (PIP) to ensure it is working correctly.

Image No.7 -     View of the inlet entrance taken atop the barge gantry tower at low tide showing Barretta (left) and the Praia de Faro (right).

Image No.8 -     View from the rear of Barretta towards Praia de Faro showing start of sand bar turning sharp right.

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Image No.9  -     Members of the University of the Algarve setting an instrument goal post system for surf zone investigations.

Image No.10 -    Data collection in the field. The fieldsite huts were still under construction but were still useful !

Image No.11 -    Aolian created surface bedforms. Note the tracks made by a saltating shell at the bottom of the image.

Image No.12 -    University of Bordeaux's surf zone transect. The yellow buoy marks the position of a S4 Current Meter and instrumentation package. Pressure transducers                              are also visible on some of the stakes going into the water.

Image No.13 -    Regular sand ripples revealed at low water on the Praia de Faro side of the inlet entrance.

Image No.14 -    Sunrise over Barretta.

Image No.15 -    Commuting to work in the rush hour.

Image No.16 -    The long walk home after work.

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Images No.17 - 23    Some of the flora and fauna found within the dune areas. Not the chameleon in images No. 22 & 23 which was found within the dunes.

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Image No.24 -    Readout from one of the Differential Global Positioning Systems (DGPS) used on the project to gain very accurate position fixes.

Image No.25 -    Aolian transport occurring over the beach on 9th February. The moving sand appears as three light bands from left to right in mid-picture.

Image No.26 -    Aolian transport at the point of the Praia de Faro. The steep cliff (0.7m high) has been smoothed out as sand has been deposited after passing over it.

Image No.27 -    Aolian bed ripples in front of the cliff in image No. 26.

Image No.28 -    More sand being blown over the Praia de Faro site.

Image No.29 -    A member of the University of Amsterdam weighing aolian transported sand samples caught in a sand trap.

Image No.30 -    Deposits of sand in the lee of shells shows the dominant wind direction after strong winds.

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Images No.31 - 35    Views of the Fuseta inlet to the north of the new inlet at the Praia de Faro.

Image No. 36 -         Two members of the WHOI team surveying the Fuseta inlet.

Image No.37 -          University of Bordeaux transect after a few days of data collection shows that alongshore sediment transport has been high. Compare with image No.11.

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Images No.38 - 51     Views of the inside tip of the inlet on the Praia de Faro side showing the variation in beach topography with time. Images were taken every 2 to 3                                    days. The changes to the beach profile were connected to the wave climate outside the lagoon. Waves refracted inside the entrance from the surf                                     zone predominantly on the flood tide when resistance to incoming flow was lowest. Visual observations showed that these would cut small cliffs                                     into the beach face with these sometimes surviving the next tide when a new lower cliff formed (Images No. 46 & 47). Under higher wave conditions                                     large bedforms developed as seen in image no. 50.

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Images 52 - 56            Beach cusps and waves associated with their formation and maintenance under calm conditions. These features had regular sacings with wavelengths                                     of approximately 30m. Longevity was afforded by a sustained period of shore normal approaching waves with small wave heights. The geometry of the                                     cusp basins allowed a simple feedback mechanism to concentrate waves within each of the basins maintaining while protecting the "ridges" from                                     significant wave attack. The cusps were observed to remain fairly stationary and did not migrate.

Questions or comments regarding this web page should be directed to Steve Shayler on sash@ccms.ac.uk who will be only too pleased to hear from you.

This page was updated 27/4/99.