Capítulos de livros

A surface flow hydrograph separation technique was used to compute base flow in 13 watersheds developed partially or totally in fractured massifs of Portugal. This technique consists firstly in isolating distinct precipitation/surface flow episodes, and, secondly, for each episode, in separating surface flow into base flow and direct runoff. Annual values of average and median base flow are presented for each watershed, as well as the linear equations that relate the obtained annual base flow with annual precipitation. The watersheds were grouped into four lithological groups and linear regressions were derived for these groups. In some conditions, that are assumed to be almost fulfilled in the 13 studied watersheds, groundwater recharge of the watershed equals base flow.By using the average values of annual base flow, it was possible to obtain a regression line model that relates average annual base flow (Fb) with annual average precipitation (P): Fb = 0.5210 * P 284 (mm/a). While no other new studies are developed, this model is proposed as a first approach to characterise average annual recharge of the Portuguese fractured massifs.

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

Os objectivos deste capítulo podem sintetizar-se em 3 aspectos principais: (1) introduzir os princípios básicos do transporte e do comportamento de poluentes no meio subterrâneo; (2) apresentar, de forma breve, as principais características do meio receptor que condicionam os processos de transporte referidos e (3) apresentar uma síntese do estado actual de conhecimentos sobre a poluição de solos e de águas subterrâneas, com base em resultados obtidos em mais de três dezenas de casos de estudo, em 10 países da Europa.