Gulf of Valencia Briefing Note

BRIEFING NOTES ON THE CIRCE COASTAL CASE STUDIES: THE GULF OF VALENCIA

Summary coastal fringe. approximately 85,632 km2 (Mösso et al., 2008), Within the Gulf of Cullera Bay receives which is about 16% of the Valencia (Spain), the high concentrations of surface of Spain. It termi- Ebro Delta and Cullera nutrients from the nates at the Bay are presented as ex- River Júcar and a ma- Mediterranean Sea, form- amples of coastal fea- rine outfall at Cullera ing a delta with the shape tures subject to a range and consequently suf- of an arrowhead (Figure of environmental pres- fers from problems of 2). The delta has two lit- sures and vulnerable to coastal pollution. toral spits: the Punta del the impacts of climate Warming of sea-water Fangar to the north and change. due to climate change the Trabucador Bar and could accelerate eu- the Punta de la Banya to The Ebro River has ex- trophication and fur- the South. The Ebro Delta perienced an apprecia- ther degrade water has an estimated surface ble reduction in flow quality in the bay with of 320 km2 and is divided due to greater freshwa- deleterious effects to the by the river into two hemi ter abstraction. natural ecosystem. A deltas. Some 77% of the Negligible sediment is rise in sea level could Ebro Delta is used for transported by the river further degrade the en- agriculture while the re- to the delta due to low- vironment through mainder comprises natu- er flows and the con- salinisation and ral areas of beaches, struction of dams. As a coastal erosion. marshes and lagoons. consequence, the delta has experienced in- Climate: creasing rates of coastal 1. The Ebro Delta The region has a erosion, subsidence and Mediterranean climate a decline in water qual- 1.1 Physical and socio- with temperatures sel- ity. Sea-level rise threat- economic characteristics dom higher than 35ºC or ens to accentuate these lower than 0ºC. The an- environmental prob- Geography: nual average tempera- lems and could cause The Ebro River (Figure 1) ture is 16.2ºC, with a salinisation, while an crosses the northeast of monthly maximum aver- increase in wave Spain with an estimated age of 24.2ºC in August storminess would ac- length of 930 km and a and a minimum of 9ºC in centuate erosion of the river basin comprising January. The annual aver-

1 age rainfall is 530 l/m2. winds: NE (gregal), E (lle- SW direction, although vant), SW (garbí) and NW the strongest winds come Winds: (mestral). The prevailing from the E. In the winter, In the Ebro delta area winds during the sum- winds blow more fre- there are four prevailing mer are from the S and quently from the NW.

Figure 1: Location map for the Gulf of Valencia case studies: The Ebro Delta and the Cullera embayment

Figure 2: The Ebro Delta

2 Waves: Adriatic Sea), the Ebro Sediment transport: Incident waves on the Delta is a microtidal envi- The total amount of sed- Ebro Delta come from ronment. The maximum iment transported by the three general directions: range of the astronomical Ebro River as suspended E-NE, S and NW. The tide is 0.25 m, with an av- load (fine sand) is in the wave climate of the area erage value of 0.16 m order of several thou- has a well-defined sea- (Sierra et al., 2002; 2004). sand tons per year, but sonal structure with The meteorological tide the washed load (clay three stages: A stage of (storm surge) is a compo- and mud) transported is low energy (June to nent as important (or in the order of 100,000 or September) with smaller even more important) as 150,000 tons per year. In wave heights and shorter the astronomical one, and contrast, sediment wave periods (S direc- the maximum sea-level retained by river dams tion); An energetic stage rise initiated by storm ranges from 15 to 20 mil- (October to March) with surges is about 1 m. lion tons per year larger wave heights and (Palanques and Drake, longer wave periods (E River discharge: 1987). and NW dominate) and; During the period 1960- Two stages of transition, 90, the annual average 1.2 Justification one of decreasing energy discharge of the Ebro The Ebro Delta is a valu- (April to May) and one of River (measured at able example of the vul- increasing energy (at the Tortosa, 44 km from the nerability of deltaic areas end of September). In the river mouth) was 424 of the Mediterranean to transition stages, wave m3/s (Sierra et al., 2002; climate change heights have intermedi- 2004). Mean monthly val- (Sánchez-Arcilla et al., ate values and waves ues show a maximum in 2007), and the complicat- propagate from three February (662 m3/s) and a ed interactions between main directions (E, S and minimum in August (135 socio-economic pres- NW). The annual average m3/s). However, for the sures (abstraction of river significant wave height last decade of this period and groundwater for (Hs) and mean period (1980-90) the average val- agricultural and domes- (Tz) are 0.75 m and 3.9 s ues were lower: 300 m3/s tic purposes) (Mösso et respectively, while the for the annual average; al., 2003), environmental maximum peak period 461 m3/s for the monthly pressures (subsidence, (Tp) during storms has a average maximum; and erosion and salinisation), magnitude of about 11 s. 119 m3/s for the monthly and the consequences of average minimum. In re- climate change (sea-level Tides: cent years, the Ebro has rise and wave stormi- Consistent with the experienced an apprecia- ness). A wide range of cli- Mediterranean Sea as a ble reduction in flow, due mate and marine data whole (with the exception to increasing hydraulic are available for the re- of the northern part of the exploitation. gion (Section 2.6) and a

3 wide circle of stakehold- celerate erosion, a prob- 1.5 Regional stakeholders, ers and decision makers lem compounded by policy makers, institutions have been established subsidence of the deltaic List of end users / stake- (Section 2.5). body. Sea-level rise would holders for the Ebro also affect salinisation Delta: 1.3 Key research issues through the deltaic body The main coastal prob- and river course. Wave Ebro River Authority lems identified for the storminess would mainly (Confederación Ebro delta are related to affect erosion of the out- Hidrográfica del Ebro). erosion, subsidence, and er coastal fringe, and water quality. Erosion of these effects would be Institute for the the delta is largely due to further compounded Development of the the reduction of coarse through subsidence of Ebro Region (Institut pel sediment supply from the deltaic body. Desenvolupament de les the river. Subsidence Comarques de l’Ebre). (lowering of the entire 1.4 Key areas of integration deltaic area) is largely The following are key Tarragona Coastal due to natural or impact pathways for Branch, Spanish enhanced compaction integrating impacts of Ministry of Environ- (e.g., from the reduction climate change in the ment (Demarcación de of fine sediment sup- Ebro Delta: Costas de Tarragona, plied by the river, or Ministerio de Medio pumping from ground- Sea-level rise and sub- Ambiente). water aquifers) and sea- sidence – accelerated level rise. The river is rates of erosion – Regional Ministry of highly regulated, thus degradation of coastal Territorial Policy and water quality is closely fringes and natural Public Works (Departa- related to the variability ecosystems. ment de Política Territo- in river discharge. In the rial i Obres Públiques). future, localised torren- Sea-level rise and sub- tial rain may play an sidence – salinisation – Regional Ministry of important role in water reduction in agricultur- Agriculture, Nourish- quality. The present al production and a re- ment and Rural Action threats of climate vari- duction in the availabil- (Departament d’Agri- ability identified for the ity of drinking water. cultura, Alimentació i Ebro delta are: Acció Rural). Wave storminess and i) Sea-level rise subsidence– accelerat- Regional Ministry of ed rates of erosion – Environment and ii) Wave storminess. degradation of coastal Housing (Departament fringes and natural de Medi Ambient I Sea-level rise could ac- ecosystems. Habitatge).

4 1.6 Data availability Marine water quality Hydrological data: Information available for data from the projects Daily mean discharge the Ebro Delta: FANS and PIONEER, is available for the Ebro include current veloci- River for the period Marine climate data: ty, nutrients, oxygen, 1912-2004. Two wave buoys (Cap chlorophyll, water Tortosa and Tarragona) temperature and salin- provide observed data ity, fluorescence, trans- 2. Cullera Bay on significant wave missivity, suspended height, maximum wave matter and phyto- 2.1 Physical and socio- height, mean wave pe- plankton concentra- economic characteristics riod, maximum peak tions; 1996-2000. period, wave direction Geography: and water temperature Meteorological data: Cullera bay and the estu- (early 1990s onwards). Three stations in the ary of the Júcar River SIMAR-44 data region (Deltebre, Port (Figure 1), located on the (HIPOCAS project) in- de l’Ampolla, Sant Spanish Mediterranean cludes numerical simu- Carles de la Rapita) coast (0º 13’ to 0º 15’ W lation of significant provide observed data and 39º 08’ to 39º 12’ N), wave height, mean on wind velocity and comprise a shallow basin wave period, maximum direction, air tempera- with maximum depths of peak period, wave di- ture and atmospheric around 10 m (Figure 3). rection, wind velocity pressure, water tem- The Cape of Cullera, a and direction and sea perature and sea level; rocky mass that pro- level; 1958-2001. 1997 onwards. trudes into the sea, limits

Figure 3: Location of Cullera Bay

5 the bay on its northern mountain of Cullera acts ronment. The maximum side, whereas the south- as a barrier to onshore range of the astronomi- ern end of the bay is winds, causing the wind cal tide is 0.3 m. The open. It is considered a to circle the mountain meteorological tide micro-tidal environ- and funnel through the (storm surge) has the ment, in which the net river basin. On entering same order of magnitude river and marine outfall the bay, it may be as the Ebro Delta discharges display a deflected towards the (Section 1.1). strong seasonal cycle. north, enhancing surface The dynamics of the bay currents and transport- River discharge: mainly depend on local ing the freshwater plume The Júcar River is charac- sea and weather condi- towards the cape (Mösso terised by high concen- tions (Mestres et al., et al., 2007). trations of nutrients due 2007, Sierra et al., 2007). to intensive agricultural During northerly wind Waves: exploitation of the river’s storms, the northern Cullera Bay is located drainage basin, and the part of this semi-en- within the Gulf of discharge of partially closed area becomes se- Valencia where the tidal treated domestic and riously affected by dis- range is approximately industrial wastewater charged detritus from 30 cm (spring tide) and from towns upstream. the river and marine out- has a limited fetch (the River discharge and the fall. Topographically, islands of Mallorca, marine outfall at Cullera, Monte el Oro is an im- Cabrera and Ibiza are are the main sources of portant feature of the only 230, 273 and 135 km nutrient input for the landscape north of the east of the bay). bay. The Júcar River fol- Júcar River, while on the Therefore, tides and lows a typical southern side of the riv- waves have low impor- Mediterranean pattern, er, the landscape is rela- tance relative to the wind with higher flows from tively flat. field. The significant October to May, and wave height exceeds 1 m lower flows during the Winds: approximately 15-17% of summer months. Mean The wind field of Cullera the time, and exceeds 1.5 monthly discharge varies bay is highly variable (on m only 2-3% of the time from 4 m3/s in July and the time scale of hours to (Mösso et al., 2007). August to 16 m3/s in days). Onshore winds are February. The velocity at mainly from the W, NNW Tides: the river mouth has a and NW while offshore Consistent with the rest mean value of 6-7 cm/s. winds are mainly from of the Mediterranean Sea Thus, the influence of the ESE, E and SE. (with the exception of river momentum to the However, the wind field the northern part of the overall hydrodynamics of inside the bay is far from Adriatic Sea), Cullera Bay Cullera Bay is negligible homogeneous. The area is a microtidal envi- except during extreme

6 flood events (Mösso et loaded with pesticides tourists and visitors (by a al., 2003; 2007). and fertilizers, and dis- factor of 5-10) in the charge of partially treat- summer season con- Sediment transport: ed wastewater from tributes significantly to Due to extreme pressures riverbank towns and the coastal economy but exerted on the Júcar industries into the lower may be negatively River flow, and a weir just reaches of the river, are impacted by the prob- 2 km upstream of the some of the mechanisms lems of water quality in river mouth, the amount that contribute to river the bay and by coastal of sediment transported pollution. These envi- erosion. by the river is also negli- ronmental pressures gible. increase the vulnerabili- 2.4 Key areas of integration ty of the region to Increasing sea temper- 2.2 Justification impacts of climate ature (and nutrient en- The ever-changing envi- change such as sea-level richment by industry / ronment of a coastal rise and ocean warming. agriculture / settle- embayment creates an ment) – eutrophication ecological niche that is 2.3 Key research issues – decline in water qual- important for seagrass, The dual threats of cli- ity – negative impact scallops, soft-shelled matic variability identi- on tourism / fishing in- clams, and as a breeding fied for this region dustry. ground for commercially include warming of sea important offshore fish. temperatures and an Rising sea level - river Coastal bays are also of increase in mean sea discharge – salinisa- major importance as level. Warmer tempera- tion / coastal erosion – recreational areas. tures would enhance negative impact on However, Cullera Bay is a eutrophication and in tourism. typical example of a turn further degrade multi-source polluted water quality. Sea-level 2.5 Regional stakeholders, coastal environment rise would affect river policy makers, institutions (Sierra et al, 2007). It discharge and salinisa- Stakeholders for Cullera receives the discharge of tion, similar to the Bay include: the Júcar River and of a potential impacts out- shallow marine outfall. lined for the Ebro Delta Valencia Coastal Agriculture and industry case study. Branch, Spanish exert environmental The main issues identi- Ministry of Environ- pressure on the river fied for this coastal ment (Demarcación de basin which in turn embayment are related Costas de Valencia, affects the water quality to water quality and ero- Ministerio de Medio of the bay. Abstraction of sion. The chief problem Ambiente). freshwater, which is later is one of water quality. returned to the river The high influx of Júcar River Authority

7 (Confederación riod, maximum peak Hidrográfica del Júcar). period, wave direction, wind velocity and di- Regional Ministry of rection and sea level; Agriculture, Fisheries 1958-2001. and Nourishment (Consellería de Agri- Water quality data cultura, Pesca y Ali- (ECOSUD projects): in- mentación). cluding nutrients, chlorophyll, water tem- Regional Ministry of perature and salinity, Territory and Housing suspended matter and (Consellería de Terri- phytoplankton con- torio y Vivienda). centrations. Data from different cruises be- Regional Ministry of tween 2002 and 2003. Enterprise, University and Science (Consell- Tidal gauge (Valencia): ería de Empresa, Sea level, 1992-2007. Universidad y Ciencia). Júcar River discharge Municipality of Cullera (Cullera): Total monthly (Ayuntamiento de discharge, 1911-1997. Cullera).

2.6 Data availability Acknowledgements Available meteorological, marine and hydrological CIRCE (Climate Change data for Cullera Bay: and Impact Research: the Mediterranean Wave buoy (Valencia): Environment) is funded Data on significant by the Commission of wave height, maximum the European Union wave height, and mean (Contract No 036961 wave period, 1985-2005. GOCE) http://www.cir- ceproject.eu/. This brief- SIMAR-44 data ing note forms part of the (HIPOCAS project): CIRCE deliverable Data obtained from D11.5.1. numerical simulation, including significant Final version, wave height, wave pe- January 2008

8 References: Mösso, C., Mestres, M., Sánchez-Arcilla, A., Sierra, J. P., González del Río, J., Rodilla, M. & López, F. (2003). River plume behaviour in the Spanish Mediterranean Coast. Hydromorphodynamic controls. Proc. 3rd IAHR Symposium on River, Coastal and Estuarine Morphdynamics, pp 935-945. Mösso, C., Sierra, J. P., Mestres, M., Cupul, L., Falco, S., Rodilla, M., Sánchez-Arcilla, A. & González del Río, J. (2007). The influence of topography on wind-induced hydrodynamics in Cullera Bay. Journal of Coastal Research (ISSN: 0214-8358), Special Issue 47 pp 16-29. Mösso, C., Sierra, J.P., Rodilla, M., Romero, I., Falco, S., González del Río, J and Sánchez-Arcilla, A. (2008). High Vertical Resolution Sampling in Density Interfaces of Estuaries and River Plumes. Estuaries and Coasts, In Press. Palanques, A. and Drake, D.E. (1987). Distribution des suspensions sur le plateau du delta de l’Ebre. Colloq. Int. Océanologie, Ecosystèmes de Marges Continentales, CIESM, Perpignan, 23 pp. Sánchez-Arcilla, A., Jiménez, José A. and Valdemoro, H. (2007). The Vulnerability and Sustainability of Deltaic Coasts: The Case of the Ebro Delta, Spain. Managing Coastal Vulnerability. Loraine McFadden, Robert J. Nicholls and Edmund Penning-Roswell (editors), Elseiver. 79-95 pp. Sierra, J. P., Sánchez-Arcilla, A., González del Río, J., Flos, J., Movellán, E., Mösso, C., Martínez, R., Rodilla, M., Falco, S. & Romero, I. (2002). Spatial distribution of nutrients in the Ebro estuary and plume. Continental Shelf Research (ISSN: 0278-4343), Vol 22 (2) pp 361-378. Sierra, J. P., Sánchez-Arcilla, A., Figueras, P. A., González del Río, J., Rassmusen, E. K. & Mösso, C. (2004). Effects of discharge reductions on salt wedge dynamics of the Ebro river. River Research and Applications (ISSN: 1535-1459), Vol 20 (1) pp 61-77. Sierra, J. P., Mösso, C., González del Río, J., Mestres, M., Cupul, L., Sánchez-Arcilla, A., Rodilla, M., Falco, S., Romero, I., González, D. & Puigdefábregas, J. (2007). Sources and sinks of nutrients and pollutants in Cullera Bay. Journal of Coastal Research (ISSN: 0214-8358), Special Issue 47 pp 30-38.

Authors Agustín Sánchez-Arcilla, LIM/UPC, Spain. [email protected] César Mösso Aranda, UPC, Spain. [email protected] Joan Pau Sierra, UPC, Spain. [email protected] Laboratori d’Enginyeria Marìtima (LIM/UPC), Universitat Politécnica de Catalunya c/ Jordi Girona, Barcelona, Spain

Editors Maureen Agnew ([email protected]) and Clare Goodess ([email protected]), Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich, UK.