Willamette River

The Oregon Department of Environmental Quality (DEQ) held the Willamette River basin Water Quality Data Summit (Corvallis, 2000) with the objectives of increasing awareness about the current conditions of the Willamette River Basin, exchanging information about water quality monitoring in the Basin, and addressing and explaining the TMDL development process.

Presentations on physical and chemical data were made by McKenzie Watershed Council, EPA, City of Salem, National Council Air & Stream Improvement, NRCS, ODEQ, and USGS.  Presentations on water quantity were made by USGS and OWRD.   Riparian vegetation and aquatic habitat were covered by EPA, OSU – Pacific NW Ecosystem Research Consortium, BLM, USFS, and ODFW.  Much of the data presented were concerned with regions outside of the model’s boundary conditions discussed in this report, namely upstream of Salem and in the headwaters controlled by the USFS and BLM.

The DEQ Water Quality Division presented the Willamette River Technical Advisory Steering Committee (WRTASC) studies of dioxin and furan concentration & effects in Willamette River fish as well as distribution of dissolved pesticides in the Willamette River basin.  These studies led to a 1999 study initiated to investigate the risk to human health from the consumption of fish from the Newberg Pool area, the level of bacteria contamination in and upstream of the Newberg Pool, and evaluate the in-situ fish embryo bioassay.  These reports can be downloaded from http://waterquality.deq.state.or.us/wq/Willamet/reports2000.htm

The Willamette River is listed in the 303(d) list for temperature because it exceeds water quality standards. DEQ held the water quality summit to involve different agencies collecting water quality data in the Willamette River so they can evaluate who has water quality data and what kind of data is available for developing the TMDLs.

The City of Portland, Bureau of Environmental Services (BES) has been collecting water quality data in the Willamette River during the last 8 years. BES collects data at 6 monitoring stations along the Willamette River as shown in Table 1 and Figure 3. Grab samples are taken weekly for the period 1992-2000 and 2 Hydrolabs took continuous measurements from 1997-2000. Both the grab samples and the Hydrolab measurements are made at a 10-foot depth. Figure 4 and Figure 5 are examples of the Hydrolab time series data at St. John's Railroad Bridge (RM 6.8) and the Waverly Country Club (RM 17.9) for the period 1992-2000.  Annual continuous Hydrolab data plots for both sites can be found in the web section called Hydrolab.
 

Low concentrations of dissolved oxygen can be observed in Figure 4 and Figure 5 during the summers of 1998 and 1999.

Longitudinal profiles for temperature, dissolved oxygen, conductivity and pH were also plotted using the grab samples provided by BES.  Figure 6 shows monthly averages for the year 1995. The monthly average for the parameters plotted seem to be constant along the Willamette River except for conductivity which increases slightly near the confluence with the Columbia River. Other parameters such as ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen, O-PO4, BOD5, fecal coliform, E. coli, enterococcus, TSS, TDS and TS were also plotted against river mile. These data were plotted for the period 1992-2000 using summer averages from May 1st to September 30th for available data as shown web section on longitudinal profiles.  Figure 7 shows a comparison between TSS, TDS and TS where an increase in these parameters can be observed near the confluence with the Columbia River.

Lateral analysis

The Grab samples collected by BES include weekly data from 1992 to 2000 on the east and west banks and from the middle of the river for several locations These data were used to verify if a laterally averaged model would be appropriate for the Willamette River.  Data from 1992 to 2000 were used to create time series plots for each sample location as shown in Figure 8 for dissolved oxygen. The standard deviation was estimated using the east, middle and west measurements at each location. Figure 9 shows the standard deviation for dissolved oxygen at each of the monitoring stations. The results obtained from this analysis show small variations in the dissolved oxygen across the river channel. However, these results are affected by sampling errors as can be observed in Figure 8 as spikes. The same analysis for other parameters such as pH, conductivity and temperature show similar results and can be found in the websections grab sampel sand grab samples standard deviations.

Vertical Profiles

The City of Portland Bureau of Environmental Services started a new monitoring program in the Willamette River in the summer of 2000 with a sample frequency of two weeks from July to October. Temperature, conductivity, pH, and dissolved oxygen samples were taken every 10 feet at four locations, Table 2.  Vertical profiles were taken from the east and west banks and from the middle of the river for each location. Figure 10 shows temperature profiles for the summer 2000 in the middle of the river at Waverly Country Club. Figure 11 shows dissolved oxygen profiles for the same location and time period. Profiles for the other locations are in Appendices E through H.

Temperature and dissolved oxygen measurements collected by BES in the Willamette River (RM 1.1 to RM 17.9) do not show significant stratification during the summer 2000 below the10-ft depth (Figure 10 and Figure 11). Unfortunately, the sampling program did not measure the near surface temperature and dissolved oxygen above the 10-ft depth except on the first day of the monitoring program (July 12, 2000). In Figure 10 and Figure 11, slight stratification seems to exist in the top 10-ft of the river. Additional vertical profiles for temperature and dissolved oxygen are shown in the websection vertical profiles. Conductivity and pH show small variations below the10-ft depth. Data for the top 10-ft is also missing for all days except 7/12/2000. Conductivity and pH profiles can be found in the websection vertical profiles..

Temperature stratification in the Willamette River (RM 1.1 to RM 17.9) could be a consequence of higher water level elevations in the Columbia River than in the Willamette River. This occurs at the end of spring and beginning of the summer. The difference in water levels produces a Columbia River water intrusion in the Willamette River moving upstream creating a bottom wedge of Columbia River water (Bloom, 2000).
 
 

Columbia River

The Oregon Department of Environmental Quality (DEQ) and Washington Department of Ecology (Environmental Information Monitoring) collected data for the EPA STORET Program at different locations in the Columbia River and its tributaries. The U.S Geological Survey (USGS) also collected water quality data in the Columbia River as part of a dissolved gas study done in conjunction with the USACOE (Richmond, 2000). The water quality sampling locations are shown in Figure 12. Since the model will simulate the summers (May 1 to October 1) for the years 1993, 1994 and 1997 to 1999 data were obtained from 1993 to present where possible.