Technical Report No. 15

GUEMES CHANNEL AND PADILLA BAY: SURFACE CURRENTS DURING FLOOD TIDE

Douglas A. Bulthuis and Anne M. Conrad

October 1995

Bibliographic Citation
Bulthuis, Douglas A. and Anne M. Conrad. 1995. Guemes Channel and Padilla Bay: surface currents during flood tide. Washington State Department of Ecology (Publication No. SHWR-96-91), Padilla Bay National Estuarine Research Reserve Technical Report No. 15, Mount Vernon, Washington. 133 pp.

Abstract
Guemes Channel is one of the three (sources) of tidal water to Padilla Bay. More than 80% of the volume of water in Padilla Bay at high tide flows into the bay during a single spring tide cycle. In this study, the movement of surface currents from Guemes Channel into Padilla Bay during spring tides was investigated with surface drogues. Fifteen to thirty drift sticks were placed between Southeast Point and March Point, Hat Island and March Point and south of Hat Island on four dates near the time of predicted Lower Low Water. The location and time of each drift stick was determined about every 30 minutes until predicted Higher High Water. Surface currents between Southeast Point and March Point move east during flood tide and then divide and flow in three directions. Most of the water flows either north between Saddlebag and Guemes Islands or south down the Swinomish Channel. A small portion of water continues to move east into Padilla Bay. The surface water directly south of Hat Island is the major source of water that flows into the southern half of Padilla Bay.