Tributary Inflows

The majority of the tributary inflows to the Columbia and Willamette River were considered in the model. Nevertheless, a small number of these tributaries were not characterized because flow information was not available. Figure 38 shows the shaded basins where the tributary inflows were not considered explicitly in the model. An analysis was conducted using a Geographic Information System, which determined the total drainage area not considered in the model was about 0.34%. The analysis considers the entire Columbia River basin above Bonneville Dam and the entire Willamette Basin above Canby Ferry which are not shown in Figure 38.

Figure 38. Columbia and Willamette River tributary inflows, shaded basins have no flow data

Willamette River

Flow

The data set for the Willamette River tributaries was obtained from the USGS gage stations shown in Table 8 and their locations are shown in Figure 39. The extent of the data can be found in Appendix I. Input files for the model were developed using continuous and daily data; however, correlations were also developed using nearby stations to fill data gaps when they existed.

Site ID	Tributary
USGS14211820	Columbia Slough
USGS14211550	Johnson Creek At Milwaukie
USGS14210000	Clackamas River at Estacada
USGS14207500	Tualatin River at West Linn

Table 8. Willamette River Tributary gage stations

Figure 39. USGS gage stations in the Willamette River Basin

Columbia Slough flow data at the Lombard station (USGS: 14211820) and Johnson Creek flow data at Milwaukie (USGS: 14211820) are recorded continuously. The input files for CE-QUAL-W2 were created using the continuous data for the summers (May 1 to September 30) of 1993,1994, 1997,1998, and 1999. For the Johnson Creek station continuous data for the year 1997 was missing consequently daily data was used to fill in gaps for the model input file. Daily flow data for the Tualatin River gage station located at West Linn was also used to create input files for CE-QUAL-W2. Figure 40 through Figure 42 show flows in the Columbia Slough, Johnson Creek, and Tualatin River for the summer periods modeled.

Figure 40. Columbia Slough flow, m³/s

Figure 41. Johnson Creek flow, m³/s

Figure 42. Tualatin River flow, m³/s

The USGS gage station on the Clackamas River at Estacada (USGS: 14210000, RM 25.5) has recorded continuous flow data for the time periods modeled. A correlation was developed to obtain flows near the mouth of the Clackamas River using daily flow data from the Clackamas River station near Clackamas (USGS: 14211000) and daily data for the Clackamas station at Estacada from 10/01/1962 to 09/30/1983. The correlation relates daily flows between the two stations using the drainage areas as follows (R² = 0.9852):

Figure 43 shows the correlation between the Clackamas River station at Clackamas and the Clackamas River station at Estacada. Figure 44 shows the flows for the Clackamas River at Clackamas, OR, using the correlation, for the summers modeled.

Figure 43. Clackamas River near Clackamas and Clackamas River at Estacada Flow Correlation, Year 1962 to 1983

Figure 44. Clackamas River flow, m³/s

Water Quality

Temperature and water quality data for the Willamette River tributaries were obtained from the Oregon Department of Environmental Quality (DEQ), US Geological Survey (USGS), the City of Lake Oswego, and the Metro Regional Government (Metro). DEQ water quality data consist of grab samples taken at a frequency of monthly to twice a year. USGS measures continuous temperature in Johnson Creek at Milwaukie and continuous temperature, conductivity, dissolved oxygen, and pH in the Tualatin River near West Linn. The City of Lake Oswego collects water quality data in the Clackamas River (RM 0.3) every 4 hours. Some of the constituents measured are temperature, pH, alkalinity, conductivity, color, and turbidity. Metro has a continuous Hydrolab in the Columbia Slough that measures temperature, dissolved oxygen, dissolved oxygen saturation, conductivity, and pH.

Data provided by these agencies were combined to generate input files for the model. Figure 45 through Figure 47 and Figure 49 show water temperature for the Willamette River tributaries. In the Columbia Slough there was a lack of temperature data at Lombard St. Bridge (LOM, RM 0.45) so a correlation was developed with temperature measurements at Saint John's Landfill Bridge (SJB, RM 2.9). The correlation is shown in Figure 48 and resulted in the correlation equation: LOM Temp(C^o)=0.9118(SJB Temp(C^o) + 0.6183 (R²=0.9584). Figure 49 shows the LOM temperature data and temperatures obtained from the correlation. Table 9 shows a list of water quality parameters available for the Willamette River tributaries. The procedure used for developing the water quality files from data can be found in Appendix J: Water Quality file development procedures.

Figure 45. Johnson Creek water temperature, ^oC

Figure 46. Tualatin River water temperature, ^oC

Figure 47. Clackamas River water temperature, ^oC

Figure 48. Columbia Slough Water Temperature Correlation

Figure 49. Columbia Slough water temperature, ^oC

Parameter	Clackamas River	Johnson Creek	Tualatin River	Columbia Slough
ALKLNITY WTR DISS	X
BOD	X	X	X	X
CAL HARD CA MG		X	X	X
CHLRPHYL A	X	X	X	X
COLOR	X	X	X
Conductivity	X	X	X	X
D ORG C C		X
DO, % sat	X	X	X	X
DO, mg/L	X	X	X	X
E.COLI	X	X	X	X
ENTCOCCI	X	X	X	X
Fecal Coliform	X	X	X	X
HARDNESS	X	X		X
NH3				X
NH3+NH4- N DISS		X	X
NH3+NH4- N TOTAL	X	X	X	X
NH3-N				X
NH4				X
NO2&NO3 N-DISS	X	X	X	X
NO2&NO3 N-TOTAL	X	X	X	X
NO2-N DISS		X	X
NO3				X
NO3-N				X
NO3-N TOTAL			X
OPO4				X
PH	X	X	X	X
PHOS-DIS		X
PHOS-DIS ORTHO	X	X		X
PHOS-T ORTHO			X
PO4-P				X
S ORG C C		X
SUSP SED CONC	X	X	X
SUSP SED PARTSIZE	X
T ALK CACO3	X	X	X	X
T ORG C C	X	X	X	X
TDS				X
Temperature	X	X	X	X
TOC				X
TOT HARD CACO3			X
Total Phosphorus	X	X	X	X
T-PO4				X
TSS				X
Turbidity	X	X	X	X
UN-IONZD NH3-N	X	X	X	X
UN-IONZD NH3-NH3	X	X	X	X

Table 9. Water Quality parameters available for the Willamette River tributaries

Columbia River

Flow

The major tributaries to the Columbia River, excluding the Willamette itself, are identified in Table 10. Flow data for these tributaries was obtained from USGS gage stations and from the Washington State Department of Ecology (WADOE). Figure 50 shows the locations of the USGS and WADOE stations used to develop the input files for CE-QUAL-W2. Figure 51 shows the watersheds included in the model. The extent of the data can be found in Appendix I.

The Washington State Department of Ecology conducted a study to characterize baseflows for rivers and streams in Washington (Sinclair and Pitz, 1999). Table 10 has six stations where recent flow measurements were not available but the State of Washington estimated monthly baseflows. These stations were used to develop input flows for the model.

USGS14142500	Sandy River Below Bull Run River, OR
USGS14143500	Washougal River Near Washougal, WA
USGS14144000	Little Washougal River Near Washougal, WA
USGS14220500	Lewis River at Ariel, WA
USGS14243000	Cowlitz River at Castle Rock, WA.
WSDE14246000	Abernathy Creek near Longview, WA
WSDE14246500	Mill Creek near Cathlamet, WA.
WSDE14243500	Delameter Creek near Castle Rock, WA.
WSDE14245000	Coweman River near Kelso, WA.
WSDE14223500	Kalama River below Italian Creek near Kalama, WA.
WSDE14221500	Cedar Creek near Ariel, WA.

Table 10. Columbia River Tributary gage stations

The inflow to the Columbia River from the Grays-Elokoman basin was characterized by adding baseflows for the Abernathy Creek near Longview and Mill Creek near Cathlamet as shown in Figure 50. Figure 51 also shows the portion of the Grays-Elokoman basin that contributes to the model domain. The input file for the model was created using monthly averaged baseflows for the summer months modeled since no other data were available.

Kalama River flows were also characterized using monthly baseflows estimated at the Kalama River near Kalama as shown in Figure 50, since the basin was lacking flow data. Figure 51 shows the size of the Kalama basin. Figure 52 shows the flows for the Grays-Elokoman basin and the Kalama River for the summers modeled.

Figure 50. Columbia River Tributary gage stations

Figure 51. Washington basins considered in the model

Figure 52. Grays-Elokoman Basin and Kalama River flows, m³/s

The Cowlitz basin was characterized using continuous data for the Cowlitz River station at Castle Rock (USGS: 14243000) for the summers of 1994, and 1997 to 1999 and daily data for 1993 since there was a gap in the continuous data. Figure 51 shows the Cowlitz basin and its tributaries. The data from this station were added to the baseflows estimated at the Delameter Creek station near Castle Rock and the Coweman River station near Kelso to obtain the total Cowlitz basin inflow. Figure 53 shows flows for the Cowlitz River for the modeled summer periods.

Lewis basin flows were calculated by adding daily average flows for the Lewis River station at Ariel and the East Fork of the Lewis River. Figure 51 shows the Lewis River Basin and its tributaries. Additionally, the baseflows from Cedar Creek were incorporated to generate the total inflow from the Lewis River Basin. Lewis River inflow to the Columbia River for the modeled periods are shown in Figure 54.

Figure 53. Cowlitz River flow, m³/s

Figure 54. Lewis River flow, m³/s

The flow for the Washougal River was estimated based on correlations between the East Fork of the Lewis River and the Washougal River and the Little Washougal River. First, a correlation relating daily flows in the East Fork of the Lewis River with daily flows in the Washougal River was developed from the period 10/01/1944 to 9/30/1981. Figure 55 shows the Washougal and East Fork Lewis River Basins. The East Fork of the Lewis River was selected for the correlation because it is an adjacent basin to the Washougal River. This correlation is shown in Figure 56 (R² = 0.9744).

Figure 55. Lewis and Washougal River Basin

The second correlation relates daily flows in the East Fork of the Lewis River with daily flows in the Little Washougal River. This correlation was developed for the period 7/01/1951 to 11/10/1955 and is shown in Figure 57 (R² = 0.9261). The daily flows for the Washougal River and the Little Washougal were calculated based on these correlations and added together to create the tributary inflow for the model. Figure 58 show the Washougal River flow for the modeled time periods.

Figure 56. East Fork of Lewis River and Washougal River correlation, Year 1944 to 1981

Figure 57. East Fork of Lewis River and Little Washougal River correlation, Year 1951 to 1955

Figure 58. Washougal River flow, m³/s

Sandy River flows were characterized based on the USGS gage station located below the confluence with the Bull Run River (USGS: 14142500). Continuous flow data for the summers of 1993 and 1997 to 1999 were used to generate the inflow files for the model. However for 1994 daily data were used because there was a gap in the continuous data record. Sandy River flows for the summers modeled are shown in Figure 59.

Figure 59. Sandy River flow, m³/s

Water Quality

The Oregon Department of Environmental Quality (DEQ) and the Washington Department of Ecology (WADOE) collect data on some of the tributaries to the Columbia River. DEQ (EPA STORET Program) water quality data consists of grab samples that are taken at a frequency of monthly to twice a year. Water quality data from WADOE (Environmental Information Monitoring) are taken on a monthly basis.

Water quality data from DEQ and WADOE were combined to generate the input files for the model. Figure 60 shows the inflow temperature for the Columbia River tributaries. In some cases no data were available for a given year on a tributary so data from the year before or after was used. In the case of the Grays-Elokoman basin, no temperature data was available at all, so temperature data was used from the adjacent Cowlitz River basin. Table 11 shows a list of water quality parameters for which data are available for the tributaries. Since no water quality data was available for the Gray-Elokoman basin the Cowlitz River basin data was used since they are adjacent basins. The procedure used for developing the water quality files from data can be found in Appendix J: Water Quality file development procedures.

Figure 60. Washington Tributary water temperatures, ^oC

Parameter	Cowlitz River	Kalama River	EF Lewis River	Washougal River	Sandy River
ALKLNITY WTR DISS		X
Ammonia-Nitrogen	X	X	X	X
BOD					X
CAL HARD CA MG		X			X
CHLRPHYL A		X			X
COLOR
Conductivity	X	X	X	X	X
D ORG C C		X
Dissolved Nitrite	X
Dissolved Soluble	X	X	X	X
DO, % sat	X	X	X	X	X
DO, mg/L	X	X		X	X
E.COLI					X
ENTCOCCI		X			X
Fecal Coliform	X	X	X	X	X
NH3+NH4- N DISS		X			X
NH3+NH4- N TOTAL	X	X		X	X
Nitrate-Nitrite	X	X	X	X
NO2&NO3 N-DISS		X		X	X
NO2&NO3 N-TOTAL	X	X		X	X
NO2-N DISS	X	X		X	X
PH	X	X	X	X	X
PHOS-DIS		X			X
PHOS-DIS ORTHO	X	X		X	X
SUSP SED CONC					X
Suspended Solids	X	X	X	X
T ALK CACO3					X
T ORG C C					X
Temperature	X	X	X	X	X
TOT HARD CACO3	X	X
Tot Persulfate Nitrogen	X	X	X
TOTAL N N	X			X
Total Phosphorus	X	X	X	X	X
Turbidity	X	X	X	X	X
UN-IONZD NH3-N		X		X	X
UN-IONZD NH3-NH3		X		X	X

Table 11. Water Quality parameter available for the Columbia River tributaries