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- Evaluation of water resources in a high-mountain basin in Serra da Estrela, central Portugal, using a semi-distributed hydrological modelPublication . Espinha Marques, J.; Samper, J.; Pisani, B.; Alvares, D.; Carvalho, J. M.; Chaminé, H. I.; Marques, J. M.; Vieira, Goncalo; Mora, Carla; Sodré Borges, F.High-mountain basins provide a source of valuable water resources. This paper presents hydrological models for the evaluation of water resources in the highmountain Zeˆzere river basin in Serra da Estrela, Central Portugal. Models are solved with VISUAL BALAN v2.0, a code which performs daily water balances in the root zone, the unsaturated zone and the aquifer and requires a small number of parameters. A lumped hydrological model fails to fit measured stream flows. Its limitations are overcome by considering the dependence of the temperature and precipitation data with elevation and the spatial variability in hydrogeomorphological variables with nine sub-basins of uniform parameters. Model parameters are calibrated by fitting stream flow measurements in the Zeˆzere river. Computed stream flows are highly sensitive to soil thickness, whereas computed groundwater recharge is most sensitive to the interflow and percolation recession coefficients. Interflow is the main component of total runoff, ranging from 41 to 55% of annual precipitation. High interflows are favored by the steep relief of the basin, by the presence of a high permeability soil overlying the fractured low permeability granitic bedrock and by the extensive subhorizontal fracturing at shallow depths. Mean annual groundwater recharge ranges from 11 to 15% of annual precipitation. It has a significant uncertainty due to uncertainties in soil parameters. This methodology proves to be useful to handle the research difficulties regarding a complex mountain basin in a context of data scarcity.
- Daily minimum air temperatures in the Serra da Estrela, PortugalPublication . Mora, Carla; Vieira, Goncalo; Alcoforado, Maria JoaoThe Serra da Estrela is part of the Iberian Central Cordillera and is the highest mountain in Portugal (1,993 m ASL). The Torre-Penhas Douradas and Alto da Pedrice-Malhada Alta plateaus with altitudes between 1,400 and 1,993m, which are separated by the Alforfa and Zêzere valleys dominate the highest part of the range. The central massif is dissected by several glacially sculpted valleys that originate reliefs from 200 to 700m. This morphological diversity controls to a great extent the local climates of the mountain. Nine air temperature data loggers were installed in contrasting topographic situations, with special emphasis to valley floors and interfluve sites. Data collection was made each 2-hours from 27th December 1999 to 27th March 2000. Minima temperature most of the times occurs at 7 UTC. The minimum air temperature patterns based on the data from the nine sites were classified using k-means. Two contrasting events were chosen for the centroids of the classification. Cluster 1 represents the stable events with thermal inversions in the valleys and higher temperature in the interfluves. The valley floors at higher altitudes present lower temperatures than the ones at lower positions. Cluster 2 groups the unstable episodes with more turbulence and a temperature decrease controlled by altitude. In this group temperature does not depends on the topographic position.