Tidal characteristics in the Canal Principal, Bahía Blanca Estuary, Argentina

PICCOLO, M.C.; FAVIER, T.

Mar del Plata

Congreso; 2001. IAPSO -IABO Meeting. The 2001 Ocean Odyssey; 2001

IAPSO-IABO

The Bahía Blanca estuary is located in the southwest of the Buenos Aires Province, Argentina. It is considered the second largest estuary in the country after the Rio de la Plata. The estuary has a main channel, Canal Principal, where the major secondary channels flow into it. The larger energy input into the estuary system is produced by a standing asymmetric semidiurnal tidal wave. Sea level observations at three stations, Ing. White Harbour, Puerto Belgrano and the Oceanographic Tower, along the northern coast of the Canal Principal during one year at ten minutes interval are used to study the tidal and subtidal fluctuations. Meteorological information was obtained at Ing. White. Standard statistical methods and Fast Fourier Transform were used to analyze the data. The mean tidal range increases from 2.41 m at the Oceanic Tower, near the mouth of the Canal Principal, to 3.60 at Ing. White Harbour. The tides show a progressively increasing phase lag from the mouth to the head of the Canal Principal. The phase lag is highest for the high tides, over 90 minutes between Oceanic Tower and Ing. White. M2 is the most important mean constituent of the tides in the Bahia Blanca Estuary, followed by S2, N2,L2 and K1 at Ing. White and Puerto Belgrano, and K1, S2 and O1 at Oceanic Tower. The shallow water components of the tides increase considerably from Oceanic Tower to Puerto Ing. White. At subtidal frequencies, the sea level variations are primarily affected by atmosferic forcing. Spectral analysis evidenced atmospheric forcing into the estuary at sinoptic and local scale.