The INDIA project undertakes to improve present knowledge of the physical processes at work at the entrance and along coastlines adjacent to a tidal inlet system through the combined use of field observations and numerical modelling and to develop methodologies to predict change. Results from INDIA will have a wide application both within Europe and beyond through improved understanding of complex interactive processes and morphodynamic response at the INDIA field site and through the provision of a comprehensive field data base for testing and development of interactive numerical models. International interest in the work is reflected by the inclusion in the project of research teams from the USA, Australia, Korea and Poland.

Motivated by a need to improve understanding of physical processes at work in the coastal zone, the primary objective of INDIA is:

"To understand complex interactions between waves, tidal flow, sediments and related phenomenon which determine the morphodynamic behaviour and stability of tidal inlet entrances and adjacent coastlines and to develop methodologies by which processes may be incorporated into numerical models in order to predict change".

To meet these objectives, a natural, relatively simple, and dynamic coastal site located in the Ria Formosa, Algarve, Portugal has been identified by the INDIA Partnership as being an ideal place for the investigation of interactive physical processes using a combined fieldwork and numerical modelling approach.

The Field Site

The Ria Formosa region, Algarve, southern Portugal, (Figure 1) is essentially a completely natural coastal system consisting of a large tidal lagoon, bounded on the seaward side by 7 major barrier islands. The area has an open ocean coast characterised by wave heights in the range 1-4 m and wave periods in the range 6-16 seconds. Tidal elevations fall within the range 2-4 m.

Abundant sediment supply to the islands is derived principally from cliff erosion to the west. Following field visits and aircraft reconnaissance of the entire barrier island system the site selected for the INDIA field study is located on Peninsula do Ancao (Figure 2). The inlet accounts for approximately 10% of the total tidal flow between the Ria Formosa lagoon and the sea and is approximately 200 m wide. The inlet is characterised by strong tidal flows, significant sediment transport and well developed flood and ebb tidal deltas(Figure 3). The reflective beach adjacent to the inlet on Peninsula do Ancao is subjected to overwash during spring tides and during storms has only embryonic aeolian dunes on the island crest and backshore. Owing to the extreme climate of the area and to low biomass production these features are highly mobile and are subjected to frequent cycles of formation and destruction by overwash and aeolian processes.

The geographical extent of the site is relatively small (less than 2.5 km² ) and encompasses flood and ebb tidal deltas, the tidal inlet and adjacent beach and aeolian dune systems At this macro-tidal site, high suspended sediment loads carried by strong longshore currents along a straight coastline interact with discharge from a small tidal inlet and with short and long period waves. The close proximity of a range of sedimentary environments at this site make it possible to undertake synchronous studies of inlet hydrodynamics, interaction between waves and inlet discharge and the mobilisation and transport of sediments by water and air. Since changes in morphology brought about by hydrodynamic and aeolian processes at this site are known to be extremely rapid, it is an ideal field location for the integrated study of coastal zone processes of wave / current / sea bed interactions and a rigorous test case for the validation of existing state-of-the-art hydrodynamic and morphodynamic numerical models. Such model tools are vital if engineers and managers are to produce effective plans for management of the coastal zone. Specific Objectives of INDIA In order to understand hydrodynamics and sediment dynamics in the vicinity of the inlet, INDIA has identified the following specific objectives. These are listed below for each sedimentary environment.

1. Tidal inlet Hydrodynamics

   Interactions between tidal inlet flows,

   waves and longshore currents.

   Mechanisms by which sediment passes a tidal inlet.

   Dynamics of flood and ebb tidal deltas.

   Bedload and suspended sediment flux through a tidal inlet.

   Inlet erosion and accretion processes.

   Inlet and channel bed sediments and bedforms.

   Turbulence structure of tidal inlet flow.

   
   

2. The surf / swash zone
   

   Boundary conditions imposed on the surf zone

   by lower shoreface morphology.

   The time response of the lower shoreface to external forcing.

   Study of the processes driving vertical circulation's.

   Examination of factors influencing bar development,

   growth, migration and decay.

   Convergence and divergence of horizontal and vertical flows

   in the nearshore region.

   Evaluation of the effects of wave asymmetry in near-bed

   mass transport processes.

   The mode, magnitude and direction of sediment transport

   inside the surf zone.

   Bedforms and bedform evolution in the surf zone.

   Turbulence in the surf zone.

   
   

3. The beach and aeolian dunes

   Morphological response of aeolian dunes to calm and

   storm periods.

   Aeolian dune evolution.

   Interactions between overwash and aeolian processes.

Poster Illustrations

The following illustrations describing the INDIA Project were taken from the award winning* INDIA poster and provide details of the INDIA Partnership, numerical modelling activities and fieldwork plans.

*First prize at the Third European Marine Science and Technology Conference, Lisbon, Portugal.