Effects of Dredged Fluid Mud on the Suspended Sediment Transport in PuertoGalván, Argentina Gerardo M. E. Perillo Instituto Argentino de Oceanografía, CC 804, 8000 Bahía Blanca, Argentina Departamento de Geología, Universidad Nacional del Sur, San Juan 670, 8000 Bahía Blanca, Argentina

Puerto Galván

Objectives PAnalize the effects of artificially generated fluid mud on the suspended sediment distribution PDefine residence time of the fluid mud PDetermine the circulation pattern of the suspended sediment fluxes at the area

METHODOLOGY GEOMORPHOLOGY PBathymetric (double frecuency) and side-scan sonar surveys PBottom sediments SEDIMENT TRANSPORT P6 cruises within 1 month (27-11/27-12/00) - ADCP P5 cross-sections PData included: velocity and suspended sediment concentration profiles every 2 s along the cross- section

Side Scan Sonar Tracks

Cruises PDraga IV.- 27 November 2000 PDraga V.- 30 November 2000 PDraga VI.- 6 December 2000 PDraga VII.-12 December 2000 PDraga VIII.- 20 December 2000 PDraga IX.- 27 December 2000

Location Cross-sections and Calibration Station

PTO. GALVAN Escarpas Pérdida del Fondo Fango Fluido Escarpas Surcos de Dragado Fango Fluido Ruido Fango Fluido 28 NOV 2000

PTO.GALVAN Pérdida del Fondo Escarpas Fango Fluido Surcos de Dragado Fango Fluido Escarpas Ruido Escarpa Fango Fluido 28 DIC

N S distancia (m) p r o f u n d i d a d ( m ) pierna NOV pierna DIC Dragado 30 Nov. N S distancia (m) p r o f u n d i d a d ( m ) pierna DIC pierna DIC pierna DIC pierna DIC pierna NOV pierna NOV N S distancia (m) p r o f u n d i d a d ( m ) pierna DIC pierna NOV pierna NOV

TIME VARIATION OF SUSPENDED SEDIMENT FLUXES

TIME VARIATION OF SUSPENDED SEDIMENT CONCENTRATION

:009:0011:0013:0015:0017:0019:0021:00 Time :009:0011:0013:0015:0017:0019:0021:00 Time H (m) FSS - Draga IV

:0011:0013:0015:0017:0019:0021:0023:00 Time FSS (Kg seg ) Dredging :0011:0013:0015:0017:0019:0021:0023:00 Time

Conclusions Geomorphology PBottom changes only on the northern portion of the Principal Channel PFluid mud found at both SSS surveys

Conclusions Sediment Transport PSS fluxes are concentrated at the center and southern parts of the Canal PCirculation is affected by wind conditions PIncrease in up to 40% in SSC from natural conditions PThere are other sources of SS, of the same order than dredged material PDredged fluid mud were redistributed in a very short time