Assessment of suspended matter input into the oceans by small mountainous coastal rivers:: the case of the Bay of Biscay

The specific yield of the Nivelle River (238 km(2)) was estimated in the range of 75 t.km(-2).yr(-1) in 1996 and 1997 with a high-frequency monitoring. This reliable result allowed us to assess the contribution of small mountainous rivers to the sediment fluxes into the Bay of Biscay: 1.9 Mt.yr(-1), i.e. 52 % of the total input (3.7 Mt.yr(-1)). Moreover, whereas the Gironde River has a larger contributive area (75 000 km(2)), its suspended sediment input into the ocean is only 42 % of the total flux (1.5 Mt.yr(-1)). Therefore, we emphasize the importance of small mountainous river TSM inputs in sedimentological and biogeochemical processes occurring on the continental margins. ((C) 1999 Academie des sciences / Editions scientifiques et medicales Elsevier SAS.).