Case Tejo/Tajo/Tagus: The Spanish perspective

Transcription

1 Case Tejo/Tajo/Tagus: The Spanish perspective Santiago Beguería-Portugués Sergio M. Vicente-Serrano Pyrenean Institute of Ecology Spanish Council of Scientific Research Campus de Aula Dei, P.O. Box 22, Zaragoza 58, Spain

2 Geographical characteristics Hydrological characteristics Water resources management Water use conflicts, problems and uncertainties Key aspects to study

3 Geographical characteristics The relief Central range Iberian range Sedimentary basin Toledo mountains 19 km (73% in Spain, 27% in Portugal) 8,1 km 2 (69% in Spain): km % > 1 m 3% > 15 m

4 Geographical characteristics Geology Granite Limestone Sedimentary basin Quartzite and Shale

5 Geographical characteristics Climatology Precipitation Cáceres Temperature (ºC) Precipitation Navacerrada Ja F M A My J Jl Aug S O N D Temperature (ºC) Ja F M A My J Jl Aug S O N D Precipitation Toledo Temperature (ºC) Precipitation Madrid Ja F M A My J Jl Aug S O N D Temperature (ºC) Ja F M A My J Jl Aug S O N D

6 Geographical characteristics Climatology Precipitation

7 Geographical characteristics Climatology Temperature

8 Geographical characteristics Climatology Climatic Water Balance Potential Evapotranspiration

9 Geographical characteristics Land-cover Percentage Land use and land cover Urban and industrial areas 1.67 Non-irrigated arable lands Irrigated lands 3.47 Vineyards and olive grooves 3.79 Pastures Mixed agricultural/natural vegetation Forests Shrubs and maquia 24.8

10 Geographical characteristics Population 15% of the Spanish population (11% of the territory)

11 Hydrological characteristics Fluvial system 1223 Hm 3 of total contribution in Spain Complexity of the drainage system Tagus river

12 Hydrological characteristics Fluvial system 1223 Hm 3 of total contribution in Spain Reservoirs

13 Hydrological characteristics Hydrological regime Monthly average discharge (Hm 3 ) Total average Ja F M A My J Jl Aug S O N D Monthly average discharge (Hm 3 ) Peralejos Ja F M A My J Jl Aug S O N D Monthly average discharge (Hm 3 ) Valdecañas Ja F M A My J Jl Aug S O N D Monthly average discharge (Hm 3 ) Trillo Ja F M A My J Jl Aug S O N D

14 Hydrological characteristics Temporal variability Total river discharges Total average Total river discharges Peralejos Total river discharges Valdecañas Total river discharges Trillo

15 Water resources management Water uses Urban and industrial consumption (6,99, inhabitants) Irrigation (23,72 ha) Water transfer (average = Hm 3 ) Refrigeration of power stations (coal and nuclear)

16 Water resources management Tagus Basin Agency (Ministry of Environment) manages the water resources in the basin. Reservoir Irrigation Urban and industrial consumption

17 Water resources management Reservoirs Hm 3 of capacity in the reservoirs (Spain) 1 14 Number of reservoirs Total volume (Hm 3 )

18 Water resources management Reservoirs 82 reservoirs in the Spanish basin Total number Total volume Absolute frequency < > % 45% 27.5% 13.7% 3% Urban/industrial use Hydroelectric production 3.4% 45.3% 19.7% Volume (Hm 3 ) Irrigation Mixed Irrigation/Hydroelectric production

19 Water resources management Reservoir s regimes Water stored (Hm 3 ) Ja F M A My J Jl Aug S O N D 9 85 Water stored (Hm 3 ) Water stored (Hm 3 ) Ja F M A My J Jl Aug S O N D Ja F M A My J Jl Aug S O N D

20 Water resources management Reservoir s regimes (water releases) Water released (Hm 3 ) Ja F M A My J Jl Aug S O N D Water stored (Hm 3 ) Water released (Hm 3 ) Ja F M A My J Jl Aug S O N D Ja F M A My J Jl Aug S O N D

21 Water use conflicts, problems and uncertainties Water transfer (Tajo-Segura) Initial prevision (1967): 6 Hm 3 /year 7 6 Total volume (Hm3)

22 Water use conflicts, problems and uncertainties Water transfer (Tajo-Segura) Territorial conflicts 26 Segura basin: increase of the tourist and irrigation demands Limit in the reservoirs (Hm 3 ) OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP June 26 = 27 Hm 3 Demand in the Segura basin 26 = 3 Hm 3 July 26: To avoid territorial conflicts the final decission depends of the central Spanish government = 82 Hm 3

23 Water use conflicts, problems and uncertainties Transboundary issues Largest reservoir in Europe Power generation Operation affects downstrem flow and river regime in Portugal Not coordinated management Alcántara reservoir

24 Water use conflicts, problems and uncertainties Hydrological droughts: from temporary to permanent 4 14 Total water stored (Hm 3 ) Water capacity (Hm 3 )

25 Water use conflicts, problems and uncertainties Hydrological droughts: from temporary to permanent

26 Water use conflicts, problems and uncertainties Hydrological droughts: from temporary to permanent. Climate connection 16 8 Total river discharges Precipitation

27 Water use conflicts, problems and uncertainties Hydrological droughts: from temporary to permanent. Water demand increase Madrid M 3 x 1 Population (millions) Water consumption Population

28 Water use conflicts, problems and uncertainties Hydrological droughts: from temporary to permanent. Water transfer River discharges hm 3 Water transfer

29 Water use conflicts, problems and uncertainties Floods Maximum annual flood (m 3 s -1 ) Trillo Maximum annual flood (m 3 s -1 ) Orusco

30 Water use conflicts, problems and uncertainties Climate change: precipitation decrease

31 Water use conflicts, problems and uncertainties Climate change: changes in atmospheric circulation POSITIVE Positive phases RIVER DISCHARGES NEGATIVE D J F M A M J J A S O N D J F M A M J J A S O N 1.5 POSITIVE Negative phases RESERVOIR STORAGES D J F M A M J J A S O N NEGATIVE D J F M A M J J A S O N 1.5 POSITIVE North Atlantic Oscillation Index North Atlantic Oscillation RESERVOIR RELEASES D J F M A M J J A S O N NEGATIVE D J F M A M J J A S O N

32 Water use conflicts, problems and uncertainties Land use changes

33 Key aspects to study To integrate water and landscape conservation and increasing water demands in a scenario of Global Change. Issues to consider: River still maintains relatively well preserved riparian landscapes, which need a certain flow (and flood) regime Tagus Basin has many reservoirs with different purposes (irrigation, urban supply and hydropower production) Irrigation is the purpose of many communities and farms, increasing the pressure over the water resources More than 6 millions inhabitants depends on the discharge of the Tagus River and tributaries to ensure their water supply Changes in water resources would affect directly the complex management of reservoirs and will obligate to raise again the uses of water within and out of the basin Any change in water management in the Spanish part of the Tagus basin will affect the quality and quantity of water resources in Portugal, thus conditioning both possible uses in the lower reaches and the price of the water.

34 Key aspects to study Many water use conflicts and the changing scenario during the last decades (climate and land-use/plant cover changes) make necessary to introduce delicate adjustments in water management. It is necessary to solve some important questions: Which is the temporal trend in the availability of water resources? Which are the factors explaining that trend? How this trend will affect to an integrated water resources management? How climate change and reservoir construction affect river regimes and management? How the Tajo-Segura transfer affects the availability of water resources downstream? Which are the consequences of the urbanisation, especially during rainstorm events? How the largest floods and droughts are managed and which is their influence in Portugal? How the enlargement of irrigated areas affect to both groundwater and surface water resources? How the integrated management of the water resources and riperine landscapes can be shared between Spain and Portugal?

35 Many thanks!