|Document Type:||Contract Report|
|Title:||Concentration, extent, and duration of salinity intrusion into the Columbia River estuary September-October, 1977-1978|
|Author/Editor:||Robert J. McConnell, George R. Snyder, Joseph T. Durkin, Theodore H. Blahm|
|Publisher:||National Marine Fisheries Service|
|Contracting Agency:||U.S. Army Corps of Engineers. Portland, Oregon|
Eight 24-h surveys were conducted during September and October 1977 and 1978 to record the extent, concentration, and duration of salinity intrusions into the Columbia River estuary. Monitoring stations were established at Tongue Point, Harrington Point, Grays Point, and in the North channel of Cathlamet Bay. The objective was to simultaneously measure salinity during maximum (spring)1 and minimum (neap)2 tidal cycles.
Monthly neap tides produced the highest concentrations with the longest durations and farthest upstream intrusions of saline waters. Salinities reached 30 parts per thousand (o/oo) at Tongue Point and 17 o/oo at Harrington Point. Concentrations of salt water exceeding 11 o/oo were measured continually throughout one 24-h survey (7-8 September 1977) at Tongue and Grays Points. The farthest upstream intrusion of salt water > 2.0 o/oo was recorded between Buoy 14 and 14A at Columbia River Mile (RM) 26.5.3
1 Tides of increased range occurring during the times of a new and full moon; these tides rise higher and fall lower than during the rest of the month.