Publication Summary

The Washington State Department of Ecology initiated monitoring of marine waters in 1967 in order to assess water quality in Puget Sound, Grays Harbor, and Willapa Bay. Data are currently collected monthly for this ongoing, long-term monitoring effort by the Marine Waters Monitoring program. Monitoring of various water quality parameters during wateryears (WYs) 1996 and 1997 occurred at 29 and 25 stations, respectively, in Puget Sound each WY. For both WYs, five stations in Grays Harbor and six in Willapa Bay were also monitored. In this report, along with the WY 1996-97 data, five indicators of marine water column environmental condition are discussed.

Appendices A, B, and C are linked below.

The Washington State Department of Ecology initiated monitoring of marine waters in 1967 in order to assess water quality in Puget Sound, Grays Harbor, and Willapa Bay. Data are currently collected monthly for this ongoing, long-term monitoring effort by the Marine Waters Monitoring program. Monitoring of various water quality parameters during wateryears (WYs) 1996 and 1997 occurred at 29 and 25 stations, respectively, in Puget Sound each WY (WY 1996 = October 1995 through September 1996). For both WYs, five stations in Grays Harbor and six in Willapa Bay were also monitored. In this report, along with the WY 1996-97 data, five indicators of marine water column environmental condition are discussed.

Climatic conditions of WY 1996-97 were characterized by higher than normal precipitation in both years, particularly during fall and winter. Air temperatures averaged close to normal throughout the two-year period. Annual runoff of two major Washington rivers (Skykomish and Chehalis) was quite high, at approximately 140-150 percent of the median flow in both years. These weather and flow conditions were evident in the sea-surface temperature and salinity of the monitoring stations. All stations showed predominately fresher sea salinity than the long-term average. Stations near rivers had a more extreme annual sea temperature range than those not near rivers.

The stratification characteristics of stations were classified into four groups: persistent, seasonal, episodic, and weak. The majority of the Puget Sound monitoring stations were either persistently (15 out of 38 stations) or seasonally (11 out of 38 stations) stratified. The degree of stratification has implications for water quality.

Dissolved oxygen (DO) concentrations <3 mg/L were measured at South Hood Canal, Penn Cove, and Discovery Bay; and <5 mg/L were found at 19 additional stations during WYs 1996-97. Observations of low DO primarily occurred in late summer to early fall but in South Hood Canal occurred year-round and reached anoxia at times. Persistent stratification co-occurred with low DO concentrations.

Very high ammonium-N concentrations (>0.14 mg/L) were seen in Budd Inlet and East Sound; high concentrations (>0.07 mg/L) were at 13 predominately South Puget Sound stations. Occurrence of consecutive months with <0.01 mg/L surface dissolved inorganic nitrogen (nitrate+nitrite plus ammonium) in combination with stratification and other indicators was used to indicate stations potentially sensitive to eutrophication. Fecal coliform bacteria counts >14 organisms/100 mL were found at 12 Puget Sound stations and seven coastal estuary stations during WY 1996-97. Of these, contamination in Grays Harbor, Willapa Bay (near the Willapa River), Commencement Bay, and inner Budd Inlet appeared chronically persistent. Other stations (e.g., Elliott Bay and Bellingham Bay) showed wintertime highs in fecal counts.