Publication Summary

The Marine Water Column Monitoring Program was initiated in 1967 to monitor ambient water quality conditions in Puget Sound, Grays Harbor, and Willapa Bay. Data are currently collected monthly as part of an ongoing, long-term monitoring component to the program. During Wateryear 1992 (October 1991 through September 1992), the Washington State Department of Ecology monitored water quality monthly at 24 stations in Puget Sound, five stations in Grays Harbor, and five stations in Willapa Bay.

The Marine Water Column Monitoring Program was initiated in 1967 to monitor ambient water quality conditions in Puget Sound, Grays Harbor, and Willapa Bay. Data are currently collected monthly as part of an ongoing, long-term monitoring component to the program. During Wateryear 1992 (October 1991 through September 1992), the Washington State Department of Ecology monitored water quality monthly at 24 stations in Puget Sound, five stations in Grays Harbor, and five stations in Willapa Bay.

Of the 48 scheduled surveys for long-term monitoring, 42 were completed. The incomplete surveys were a result of inclement weather conditions which created poor sampling conditions (i.e., low visibility and rough sea surface). Wateryear 1992 (WY 1992) was marked by warm and mild climatological conditions as a result of the well established El Nio event. Average surface water temperatures (all stations) in Puget Sound warmed earlier in the spring of WY 1992 than in the previous wateryear (1991), showing up to a 2 degree Celsius (°C) higher temperature over WY 1991. By summer, the difference in Puget Sound average surface temperatures between WY 1992 and WY 1991 was reduced to about 1°C, with WY 1992 being warmer. The 1992 surface temperatures in Grays Harbor were slightly above those seen in 1991 during the spring months, but were lower by about 3°C during the summer months. Willapa Bay average surface temperatures averaged 1°C cooler during the summer of 1992 compared to the summer of 1991. Whether these differences were specifically associated with the El Nio was not determined. Dissolved oxygen (D.O.) concentrations fell below 5.0 milligrams per liter (mg/L) at five Puget Sound stations during WY 1992. Two of these six stations were in lower Hood Canal, which experienced oxygen concentrations below 5.0 mg/L the majority of the year. Three of the stations were in North Puget Sound and only exceeded 5.0 mg/L in the late summer or early fall months. Eight Puget Sound stations and three coastal stations had fecal coliform bacteria counts above 14 organisms per 100 milliliters (mL) during WY 1992. Most of these stations also showed fecal coliform counts above 14 organisms/100 mL during the WY 1990 and WY 1991 programs. Of the 26 stations sampled for nutrients, 17 Puget Sound stations and four coastal stations indicated nutrient depletion (NO2NO3 concentrations below 0.04 mg/L) during one or more station visits during WY 1992. At many of the stations, but not all, the nutrient concentrations appeared to be depleted earlier during WY 1992 than observed during WY 1991. Furthermore, two stations (one in Georgia Strait and one in Dana Passage) that did not show nutrient depletion in WY 1991, did show nutrient depletion during WY 1992. The WY 1992 quality assurance/quality control (QA/QC) assessment showed acceptable data quality for most parameters. Precision for nutrient and chlorophyll a parameters was better for laboratory split samples than for field replicate samples. Fecal coliform bacteria results showed poor precision for both laboratory splits and field duplicates. Consequently, all fecal coliform bacteria results should be interpreted with caution and/or assumed to be estimates at best.