Ângela Canas (MARETEC, IST)
Contents 1. Introduction (relevance of coastal modelling) 2. Creating a coastal model 3. MOHID Water Modelling System (theory and practice)
Contents 3 case studies: Portuguese Continental Coast Mondego Estuary Tagus Estuary Mondego Tagus
1. Introduction
Contents 1.1. Coastal demands/problems 1.2. Modelling answer 1.3. Operational modelling
1.1. Coastal demands/problems Important sites: Coast; Estuaries: Semi enclosed areas where river and land drainage fresh water mixes with salt water; Problem management framework: RIVM (1995) Drivers/ Pressure State/ Impact Response
1.1. Coastal demands/problems Drivers/Pressures: Large human populations and intense economical activities; High biological productivity; Estuaries are very relevant for ecology issues: Optimal conditions for reproduction and nursery for 70% of marine fish species; Contribute to replenish coastal areas population; Birds nidification and inhabitation in winter; Important areas for natural purification processes; Coastal storms;
1.1. Coastal demands/problems Drivers/Pressures - Tagus Estuary case: Profitable fishing activity (Baeta et al., 2005); Biological richness and nursery areas for fish and birds; Industrial activity; Important cities (over 2 million); Intense navigation and dredging; Storms in coast (Gama et al., 1994) Guia wastewater underwater outfall Estoril coast beaches navigation Lisbon Almada Tagus River Natural Reserve of Tagus Estuary industrial belt primary production
1.1. Coastal demands/problems State/Impact: Water quality: Eutrophication; Toxic algae blooms; Sediment linked contaminants; Oil/hazard pollutants beaching from accidents; Coastal erosion;
1.1. Coastal demands/problems State/Impact - Tagus Estuary case: Pollution by industrial/domestic effluents; Heavy metals in salt marshes sediment and fauna (França et al., 2005); Toxic algae blooms in coast (Van Dolah, 2000); Coastal erosion in Costa da Caparica due to storms (Ferreira, 2004).
1.1. Coastal demands/problems Response: Large legal demands/protection: Nitrates Directive; Urban Wastewater Directive; Drinking Water Directive; Bathing Water Directive; Water Framework Directive; Ecological and economical importance of estuaries expressed in national plans (e.g. Portuguese National Water Plan); Policy decisions afecting water demand implacable scrutiny; Media and public opinion continuously exert a strong pressure over policies; Operational forecast systems.
1.1. Coastal demands/problems Response Tagus Estuary case: Monitorization of pollution from Guia wastewater outfall; Development of Tagus Estuary Operational Forecasting System (2003);
1.2. Modelling answer Decisions concerning water policies need be thoroughly supported and documented; Measurements: Discrete in time/space Past description D/P R S/I Support/documentation gathering tools: Modelling: Continuous in time/space Past description Future forecasting D/P R S/I
1.2. Modelling answer Models are naturally fitted as Decision Support Tools: Results are acceptable justification to major decisions: location of ports, sewage systems, ecological reserves; Corner stone of ecological impact studies; Integrate several system characteristics (hydrodynamics, transport and diffusion phenomena, some chemical and biochemical cycles);
1.2. Modelling answer Model use as Decision Support Tools: Detect and select the best solution; Prove that best solution was chosen; Results are not decisions: decision making is mandatory!
1.2. Modelling answer An emblematic case Mondego Estuary: Problem: Macro algae blooms; Regression of local aquatic vegetation; Concentrated in South branch; Potential problem area relative to eutrophication under OSPAR Convention Comprehensive Procedure (Pina et al., 1992); Figueira da Foz Rio Pranto Ilha Murraceira Rio Mondego Connection between North/South branch (obstructed till May 2006)
1.2. Modelling answer An emblematic case Mondego Estuary: Drivers/pressure? Nutrient loads are smaller in South branch than in North branch; Blooms follow reduction of communication between both branches in early 1990 s for economy in dredging operations (IMAR and MARETEC, 2006); Not linked to increase of nutrient loads from human activity (INAG and MARETEC, 2007).
1.2. Modelling answer An emblematic case Mondego Estuary: Drivers/pressure! Modelling study linked eutrophication sensibility to a fainter circulation in South branch due to reduced connection between the branches; Nutrient loads larger in North branch but circulation is sufficiently strong that blooms do not occur;
1.2. Modelling answer An emblematic case Mondego Estuary: Response: Model results motivated the reopening of connection between arms in 2006 to improve water quality; Measurement water quality studies after reopening evidence that model explanation is correct: Macro algae blooms do not occur again (Lillebø et al., 2005); Local aquatic vegetation is recovering (Leston et al., 2008).
1.2. Modelling answer An emblematic case Mondego Estuary: Hydrodynamic modelling was the key to solve an important ecological/water quality problem!
1.2. Modelling answer Numerical models may have different purposes (Nihoul, 1984): Tests; Process study; System management. Current research on modelling oriented towards system management: Operational modelling
1.3. Operational modelling Modelling as forecasting: Prevention/minimization of impacts: Oil spills; Contaminant spills; Algae blooms; Certification of impacts; Optimization of activities: Water resources use (e.g. surfing, bathing); Navigation; Measurement surveys; Etc.
1.3. Operational modelling Operational oceanography (Prandle, 2000): Acquisition, dissemination and interpretation of measurements of ocean conditions + Real-time modelling Forecast of future conditions Prandle (2000)
1.3. Operational modelling Components of an operational system: Numeric model Data assimilation Validation posting Measurement network
1.3. Operational modelling Desirable characteristics of models (Prandle, 2000; James, 2002): Modular architecture; Standardization of input formats; Operation in diverse computational machines and operating systems; Support parallel computation (MPI); Flexible Easily scalable Support high computational demand systems (e.g. biological model coupled with 3D hydrodynamic model)
1.3. Operational modelling Different objectives: Hydrodynamic forecast: Water level / storm surge; European Atlantic Coast; North Sea; North America Coasts; Biogeochemical/water quality forecast: Mediterranean Sea; Tagus Estuary. Water level / circulation / storm surge Biogeochemical/ water quality
1.3. Operational modelling Hydrodynamic forecast Gulf of Maine Observing System (www.gomoos.org): Princeton Oceanographic Model (POM); Water level/waves/ circulation; Main purpose: comercial fishing.
1.3. Operational modelling Hydrodynamic forecast Physical Oceanographic Real- Time System (tidesandcurrents.no aa.gov/ports.html): POM; Water level/ circulation; North American ports; Main purpose: navigation;
1.3. Operational modelling Hydrodynamic forecast Operational Model for the Portuguese Coast: (www.mohid.com/op erational/): MOHID Water; Velocity, temperature, salinity; On-line validation against buoys (Puertos del Estado, Instituto Hidrografico) and remote sensing. data.mohid.com/~luis/validation/
1.3. Operational modelling Hydrodynamic forecast Previsão da ondulação para a costa portuguesa: (www.maretec.mohid.com/ondas/): Wave Watch III; Waves; On-line validation against buoys (Puertos del Estado, Instituto Hidrografico). data.mohid.com/~luis/validation/
1.3. Operational modelling Hydrodynamic forecast Sistema Operacional para o Estuário do Tejo: (www.mohid.com/tej o-op/): MOHID Water; Hydrodynamic/Water quality (nutrients, coliforms); Tagus Estuary and Estoril coast; Main purpose: monitorization of outfall pollution. Water quality forecast
1.3. Operational modelling Sistema Operacional para o Estuário do Tejo: Fernandes (2005) at Maretec (IST) Objective: monitorization of Guia outfall pollution on estuary and beaches water quality Main end-user: SANEST S.A. (outfall operator) 1 72h 162x162 (300m) 168x223 (2km) N 2 3a 3b outfall 100x60 (35m) + Beaches 301x105 (10m) Meteo station (Guia) Hydrometic station (Ómnias) + N Tagus Estuary Water sampling Sensor data Validation and posting (http://www.mohid.com/tejo-op/) 3 nested domains: 1-2D, hydrodynamics 2-2D, 3D (11), hydrodynamics, water quality 3-3D (11), hydrodynamics, outfall pollution dillution and dispersion + Forcing: Meteo (Meteo IST) Tide (FES 95) River flow (INAG)
1.3. Operational modelling Case of Mondego Estuary: Very adequate way to manage the site sensitivity to eutrophication and other water quality problems: In every day situations; In accident situations.
References Baeta, F., A. Pinheiro, M. Corte-Real, J. Costa, P. de Almeida, H. Cabral and M. Costa, 2005, Are the fisheries in Tagus sustainable?, Fisheries Research, 76, pp. 243-251. França, S., C. Vinagre, I. Caçador and H. Cabral, 2005, Heavy metal concentrations in sediment, benthic invertebrates and fish in three salt marsh areas subjected to different pollution loads in the Tagus Estuary (Portugal), Marine Pollution Bulletin, 50, pp. 993-1018. Ferreira, J., 2004, Coastal Zone Vulnerability and Risk Evaluation. A Tool for Decision-Making (An Example in the Caparica Littoral Portugal), Journal of Coastal Research, Special Issue 39. Gama, C., J. Dias, O. Ferreira, R. Taborda, 1994, Analysis of storm surge in Portugal, between June 1986 and May 1988, Proceedings of Littoral 94, Lisboa, pp. 381-387. IMAR e MARETEC, 2006, 2ª Aplicação do Comprehensive Procedure da OSPAR no Estuário do Mondego, Lisboa. INAG e MARETEC, 2007, OSPAR Convention for the Protection of the Marine Environment of the North East Atlantic, Comprehensive Procedure, Mondego Estuary Portugal, Lisboa. Leston, S., A. Lillebø e M. Pardal, 2008, The response of primary producer assemblages to mitigation measures to reduce eutrophication in a temperate estuary, Estuarine, Coastal and Shelf Science, 77 (4), pp. 668-696.
References Lillebø, A., J. Neto, I. Martins, T. Verdelhos, S. Leston, P. Cardoso, S. Ferreira, J. Marques e M. Pardal, 2005, Management of a shallow temperate estuary to control eutrophication: The effect of hydrodynamics on the system s nutrient loading, Estuarine, Coastal and Shelf Science, 65 (4), pp. 697-707. Nihoul, J., 1984, A three dimensional general Marine Circulation Model in a Remote Sensing Perspective, Annales Geophysicae, 2, pp. 433-442. Pina, P.; Braunschweig, F.; Neves, R., and Saraiva, S., 2002. Water Quality in Portuguese Estuaries Nitrates and Urban Waste Water Directives application in Tagus, Sado and Mondego, Instituto do Mar MARETEC (IST), Lisboa. Prandle,D., 2000. Introduction: operational oceanography in coastal waters. Coastal Engineering, 41, 3-13. RIVM, 1995. A General Strategy for Integrated Environmental Assessment at the European Environment Agency. European Environment Agency. Copenhagen, Denmark. Van Dolah, F., 2000, Marine Algal Toxins: Origins, Health Effects, and Their Increased Occurrence, Environmental Health Perspectives, 108 (1), pp. 133-141.