An Analysis of Water Quality. Data in
Tualatin River Tributaries : with
D'
Oregon Water Resources Research Institute
Oregon State University
November 1992
TUALATIN RIVER BASIN SPECIAL REPORT S
The Tualatin River Basin in Washington County, Oregon, is a complex area with
highly developed agricultural, forestry, industrial, commercial, and residential activities .
Population has grown in the past thirty years from fifty to over 270 thousand .
Accompanying this population growth have been the associated ; increases
in
transportation, construction, and recreational activities . Major improvements have
occurred in treatment of wastewater discharges from communities and industries in th e
area . A surface water runoff management plan is in operation . Agricultural and forestry
operations have adopted practices designed to reduce water quality impacts . In spite of
efforts to-date, the standards required to protect appropriate beneficial uses of water have
not been met in the slow-moving river .
_
The Oregon Department of Environmental Quality awarded a grant in 1992 to 'th e
Oregon Water Resources Research Institute (OWRRI) at Oregon State University . to
review existing information on the Tualatin, organize that information so that it can b e
readily evaluated, develop a method to examine effectiveness, costs and benefits o f
alternative pollution abatement strategies, and allow for the evaluation of variou s
scenarios proposed for water management in the Tualatin Basin . Faculty members from
eight departments at Oregon State University and Portland State University ar e
contributing to. the project. Many local interest groups, industry, state and federa l
agencies are contributing to the understanding of water quality issues in the basin . This
OWRRI project is based on all these research, planning and management studies .
This publication is one in a . series designed to make the results of this projec t
available to interested personsand to promote useful discussions on issues and solutions .
You are invited to share your insights and comments on these publications and on the process in which we are engaged. This will aid . .us in moving towards a bette r
understanding of the complex relationships between people's needs, the natura l
environment in which they and their children will live, . and the decisions that will be
made on resource management .
AN ANALYSIS of WATER QUALITY DATA i n
. TUALATIN RIVER TRIBUTARIES WITH THREE DIFFERENT LAND USES '
by
J. Ronald Miner, Ph .D. and Eric F . Scott
Departments of Bioresource Engineering and Civil Engineering
Oregon State University
4
The Tualatin River Basin studies are being done under a grant from the Orego n
Department of Environmental Quality to the Oregon Water Resources Research Institute
at Oregon State University . Published by the Water Resources Research Institute .
Tualatin River Basin Water Resources Management
Report Number 2
1
TABLE OF CONTENTS
List of Figures
ii
List of Tables
v
Acknowledgement
vi
Abstract
vii
Introduction
1
Approach 1
Precipitation
2
Agricultural Sub-Basin
2
Observations, 1990
2
Observations, 1991
4
Loadings
4
Urban Basin
5
Forestry Basins 6
Summary
9
ii
LIST OF FIGURES
Figure 1 : Precipitation 1990 - Hillsboro, Oregon 10
Figure 2 : Precipitation 1991 - Hillsboro, Oregon
12
Figure 3 : Dairy Creek at Hwy 8 - Flow Rates during 1990 14
Figure 4 : Dairy Creek at Hwy 8, 1990 - Precipitation and Flow 15
Figure 5 : Dairy Creek at Hwy 8, 1990 - Flow, Total Solids (TS) an d
Nitrate + Nitrite (N02-3) 16
Figure 6 : Dairy Creek at Hwy 8, 1990 - Total (TS) an d
Dissolved Solids (TDS)
17
Figure 7 : Dairy Creek at Hwy 8, 1990 - Total Suspended Solids, mg/1
18
Figure 8 : Dairy Creek at Hwy 8, 1990 - Total and Ortho Phosphorus
19
Figure 9 : Dairy Creek at Hwy 8, 1990 - Nitrate + Nitrite N Concentration . 20
Figure 10: Dairy Creek at Hwy 8, 1990 - Ammonia N Concentration 21-
Figure 11 : Dairy Creek at Hwy 8, 1990 - Kjeldahl N Concentration
22
Figure 12 : Dairy Creek at Hwy 8, 1990 - Fecal Coliforms, No ./100 ml
23
Figure 13 : Dairy Creek at Hwy 8, 1990 - Flow v .s. Phosphate Loading
24
Figure 14 : Dairy Creek at Hwy 8 1990-91 - Total Phosphorus Load, lb ./day
v.s. flow rate
25
Figure 15 : Dairy Creek at Hwy 8, 1991 - Flow Rate, cfs ., Dairy Creek
26
Figure 16 : Dairy Creek at Hwy 8, 1991 - Flow v .s. Precipitation ,
Dairy Creek
27
Figure 17: Dairy Creek at Hwy 8, 1991 - Total and Dissolved Solids, mg/1
Figure 18 : Dairy Creek at Hwy 8, 1991 - Suspended Solids, mg/1 Figure 19 : Dairy Creek at Hwy 8, 1991 - Total and Ortho Phosphate, mg/1
. 28
29
. 30
111
Figure 20 : Dairy Creek at Hwy 8, 1991 - Ammonia N Concentration, mg/1
. 31
Figure 21 : Dairy Creek at Hwy 8, 1991 - Kjeldahl N Concentration, mg/1
32
Figure 22: Dairy Creek at Hwy 8, 1991 - Nitrate N Concentration, mg/1
33
Figure 23 : Dairy Creek at Hwy 8, 1990 - Flow and Solids Loads 34
Figure 24: Dairy Creek at Hwy 8, 1991 - Flow and Solids Loads 35
Figure 25 : Dairy Creek at Hwy 8, 1990 - Phosphorus Loads 36
Figure 26: Fanno Creek, Station #15, 1990 - Precipitation v .s. Flow
38
Figure 27: Fanno Creek at Durham, 1990 - Flow Rate, cfs 39
Figure 28 : Fanno Creek at Durham, 1991 - Flow Rate, cfs 40
Figure 29 : Fanno Creek at Durham, 1990 - Total and Dissolved Solids 41
Figure 30: Fanno Creek at Durham Rd 1990 - Total Suspended Solids
42
Figure 31 : Fanno Creek at Durham, 1990 - Total and Ortho Phosphorus
Figure 32 : Fanno Creek at Durham, 1990 - Kjeldahl and Nitrate Nitrogen
. . . 43
. . 44
Figure 33 : Fanno Creek at Durham, 1990 - Total and Ortho
Phosphorus Loads
45
Figure 34 : Fanno Creek at Durham Rd 1990-91 - Total Phosphoru s
Load, lb ./day v .s. flow rate
46
Figure 35 : Fanno Creek at Durham, 1991 - Total and Dissolved Solids 47
Figure 36: Fanno Creek at Durham Rd 1991 - Total Suspended Solids
48
Figure 37: Fanno Creek at Durham, 1991 - Total and Ortho Phosphorus
49
Figure 38 : Fanno Creek at Durham, 1991 - Kjeldahl and Nitrate Nitrogen 50
Figure 39 : Fanno Creek at Durham Rd 1991 - Ammonia N Concentrations 51
Figure 40 : Fanno Creek at Durham, 1991 - Phosphorus Loads 52
iv
Figure 41 : Gales Creek at Hwy 6, 1991 - Total Suspended Solids 54
Figure 42 : Gales Creek at Hwy 6, 1991 - Nitrate N Concentrations
55
Figure 43 : Gales Creek at Hwy 6, 1991 - Phosphorus Concentrations 56
Figure 44 : Gales Creek at Forest Park 1991 - Nitrate N Concentrations . . . . 5 7
Figure 45 : Gales Creek at Forest Park 1991 - Phosphorus Concentrations . . . 5 8
Figure 46 : East Fork Dairy Creek, 1991 - Fern Flat Road ,
Total Suspended Solids
59
Figure 47 : East Fork Dairy Creek, 1991 - Fern Flat Road ,
Nitrate N Concentrations
60
Figure 48 : East Fork Dairy Creek, 1991 - Fern Flat Road ,
Phosphorus Concentrations
61
Figure 49 : East Fork Dairy Creek, 1991 - Fern Flat Road ,
Chloride Concentrations
62
Figure 50 : East Fork Dairy Creek, 1992 - Fern Flat Road ,
Solids Concentrations
63
Figure 51 : East Fork Dairy Creek, 1992 - Fern Flat Road ,
Ortho Phosphorus, mg/l
64
Figure 52: Upper McKay Creek, 1991 - Suspended Solids Concentrations 65
Figure 53 : Upper McKay Creek, 1991 - Phosphorus Concentrations
66
Figure 54: Upper McKay Creek, 1991 - Nitrogen Concentrations
67
Figure 55: Upper McKay Creek, 1991 - Chloride Concentrations 68
V
LIST OF TABLE S
Table 1 : Precipitation during 1990 - Hillsboro, OR 11
Table 2 : Precipitation during 1991 - Hillsboro, OR
13
Table 3 : Monthly Loading Rates for Various Constituent s
Dairy Creek at Highway 8
37
Table 4 : Monthly Loading Rates for Various Constituents
Fanno Creek at Durham Road
53
vi
ACKNOWLEDGEMENT
The data evaluated in this document represent a cooperative effort involving th e
Unified Sewerage Agency of Washington County, the United States Geological Survey ,
the Tualatin Valley Irrigation District, the Washington County Soil and Wate r
Conservation District, the Soil Conservation Service, the Oregon Graduate Institute, an d
the Washington County Watermaster . All of the above worked together in collecting a n
extensive data set . Particular thanks are due John Jackson and Janet Miller of the
Unified Sewerage Agency for their special efforts in making the data available in a
convenient format .
ABSTRACT
Water quality and stream flow data for three representative land uses in th e
Tualatin River Basin were evaluated to determine the comparative levels of variou s
pollutants . In addition, the data were used in an effort to identify the extent to whic h
observed concentrations of total and ortho phosphorus could be attributed to nonpoin t
surface runoff, to groundwater inflow or to extraction from previously deposite d
phosphorus bearing sediment.
Surface runoff was not identified as a factor in determining water quality at an y
of the weekly dry season samplings in the streams flowing through agricultural an d
forested areas . Five incidents were identified in the urban area in which surface runoff
was contributing to the quality of water in the streams .
The data which were collected between May 1 and October 31 confirm that durin g
this period surface runoff has minimal impact on stream quality . The data, however, do
not distinguish between the possibilities of groundwater inflow or re-suspension o f
previously deposited sediments as being the major contributor to elevated phosphoru s
concentrations .
1
INTRODUCTION
The Tualatin River Basin near Portland is a complex mixture of urban, forestry ,
and agricultural land uses. The river itself has been classified as a water-quality limited
stream . Water quality is of particular concern during the critical late summer perio d
when excessive algae growths develop in the lower reaches of the mainstem of th e
Tualatin. This interrogation of the water quality data was undertaken to provid e
additional insights as to how different land uses impacts stream water quality .
APPROACH
Water quality data are available for several stations on the mainstem and the
important tributaries of the Tualatin River . The data for 1990 and 1991 were selecte d
for this particular study to reduce the impact of changes in the operation of sewage
treatment plants . Dairy Creek was selected as representative of the agricultural areas o f
the Basin. The sampling station at the bridge where Highway 8 crosses Dairy Creek
immediately west of Hillsboro was identified as incorporating the full complex o f
nurseries, row crops, and pasture development that represent Washington Count y
agriculture. This sampling location does not, however, allow the impact of individua l
activities to be measured .
Fanno Creek, one of the lower tributaries was selected as representative of an
urban watershed . The lowest downstream sampling station was selected because the mos t
complete data set was available .
For the forested watersheds, the selection was more difficult . There were no
stations for which a full set of water quality and flow measurements were available an d
further, examination of the data indicated there were important differences in wate r
quality depending on which basin was being considered. Thus sampling stations on Gales
Creek, McKay Creek and the East Fork of Dairy Creek will be considered .
2
PRECIPITATION
Summer and early autumn precipitation patterns are presented for the Hillsboro
Station in Figures 1 and 2. Greater detail is available by reference to Tables 1 and 2
where the individual daily data are presented.
Each year demonstrates many of the characteristics that typify western Oregon
weather, yet the two are clearly different. Late May and early June of 1990 was a
period of frequent rainfall with over 3 .4 inches of rainfall between May 15 and June 15 .
1
Sporadic rainfall events occurred in August and September . However, the next period
of significant rainfall began in October .
The rainfall pattern for 1991 was different in that there was a significant storm
in mid-May, another in mid-June, one in late August/early September, but no more stor m
events yielding more than a half-inch of rain until late October .
AGRICULTURAL SUB-BASIN
The sampling point selected to evaluate the impact of agricultural activities is th e
Dairy Creek at Highway 8. There is a calibrated staff gauge available at that point.
Flow measurements are available when water depth did not exceed the height of th e
gage . The drainage area above the sampling point represents a diverse agricultural
activities . There are numerous container and bare root stock nurseries in the immediat e
vicinity . There are also both row crops and grazing activities in the immediate vicinity .
Observations, 1990
The graph of measured flow rates is presented in Fig . 3 During the sampling for
the third week of May, the water level was above the staff gage, hence there is no flow
data. If a flow rate had been measurable, it would have been in excess of 160 cfs . Fig.
4 is a plot of both precipitation and flow rate . Several features are worthy of notice .
During mid to late May, there was precipitation of approximately 2 inches . The flow
rate increased in response to this . During early June the flow rate decreased even though
3
there was precipitation totalling 0 .67 inches during the first 8 days . The precipitatio n
of 0.54 inches on June 10 prompted a slight increase . The small rains between June 10 ,
August 15, and August 30 caused no measurable increases in flow rate . The
approximately half-inch rain on September 15 resulted in an increase in stream flow .
These observations suggest a relatively responsive system in which rainfall o f
approximately 0 .5 inches is sufficient to prompt a change in the flow rate of the stream
except during the dry period of the summer .
Figures 5, 6, and 7 are important in interpreting this discussion . First of all it
is important that throughout the year, the total solids concentration ranged fro m
approximately 70 to 155 mg/1 even though the flow rate ranged from less that •20 t o
more than 150 cfs . Figure 7 indicates that the suspended solids concentration (th e
difference between total solids and dissolved solids) is consistently less than 20 mg/ 1
except for the set of samples collected during the second week of July . Since there was
no precipitation immediately prior to that event, it was most likely caused by a specifi c
local activity upstream of the sampling station . The data strongly suggest that during thi s
May through October sampling period, erosion carried sediment (measured as suspended
solids) was not a factor in the phosphorus levels of Dairy Creek . The data do not ,
however, preclude the possibility that sediment carried into the stream during winter
months was contributing phosphorus by simple extraction during the summer . This
implies that the flow in Dairy Creek during the summer period is from groundwate r
inflow.
The total and ortho phosphorus concentrations are presented in Figure 8 . The
ortho phosphorus concentrations vary through a narrow range . Ortho phosphorus is les s
than half the total phosphorus . There is some suggestion that the ortho phosphoru s
concentrations are responsive to temperature and perhaps to flow rate (Fig . 19) . A peak
in total solids, nitrate/nitrite and ortho phosphorus all occurred on the same sampling 'day
which was not preceded by a major precipitation event (Figs . 7, 8, and 9) . Figures 1 0
and 11 show ammonia and total nitrogen .
Figure 12 presents the fecal conform concentrations. Most of the counts are less
than 600 per 100 ml, but there are two peaks, one the third week of May, the other-in
4
late October . Both of these are samples collected when flow rates were higher tha n
previous samplings, and there had been precipitation following some smaller rains . One
possible explanation of these data is that runoff from livestock or poultry production was
l
transported to the creek. Both of those peaks could have been . caused by relatively smal
amounts of runoff . Phosphorus or suspended solids associated with this much runof f
would have been undetected in the increase& flow of the week. Another plausible
explanation is that the increased flow re-suspended previously deposited coliform bearing
sediment.
Total and ortho phosphate loading rates in pounds per day correlate with the flow
rate (Figures 13 and 14) . Figure 14 includes data for both 1990 and 1991 . A straight
line relationship would say that concentrations are constant. A nearly constant
concentration again suggests groundwater as an important source of phosphate or leachin g
of phosphorus containing sediment.
Observations, 1991
• The overall patterns identified in 1990 are repeated in the 1991 data as presented
in Figures 15 through 22. Particularly interesting is to notice that the 1 .35 inch total
rains beginning on May 17 caused a major response in the flow rate, actually causing the
staff gage reading 'to exceed the established curve . An even slightly larger storm in midJune caused a much smaller response and a response spread over a longer time span .
The larger water storage capacity greatly minimized the immediate impact of the Jun e
storm. Figures 17 and 18 show that the may storm did not result in an increase
in
total
solids concentrations in the stream. Figures 19 through 22 show phosphate and nitroge n
fractions for 1991 . Nitrate increases markedly in late winter (Figure 22) .
Loadings
Figures 23 and 24 summarize the average monthly flow rates and the variou s
solids information . The solids loading follows the average flow rates . The suspended
solids are a small fraction of the total solids. The phosphorus loading rates' for 1990 are
shown in Figure 25 . Table 3 provides a more detailed summary of the loading rates fo r
1990 and 1991 .
5
URBAN BASIN
The lowermost sampling station on Fanno Creek was selected as the most
representative of an urban watershed within the Tualatin Basin . Although there is a
•significant amount of green space along Fanno Creek and its tributaries, the basin ca n
best be typified as one of urban use . Approximately
75 %
is within incorporated cit y
limits . The remainder is described as urban unincorporated .
Precipitation and flow data are shown in Figures 26 to 28 . The two June dates
for which data are not presented are dates on which the water level exceeded the top o f
the staff gage . The stream flows in Fanno Creek tend to change more dramatically in
response to rainfall events than do those in Dairy Creek (Figures 26 and 4) . These
differences can be attributed to the increased fraction of paved or otherwise impervious
area in the Fanno basin compared to the more agricultural Dairy Creek basin .
The total and dissolved solids concentrations measured in Fanno Creek under dr y
weather conditions are consistently about fifty percent higher than the correspondin g
values in the more agricultural areas (Figures 29 and 6) . Dissolved solids make up mos t
of the total. Figures 30 and 36 show the suspended solid concentrations measured at thi s
site. Three samplings during 1990 and two during 1991 had suspended soli d
concentrations in excess of 40 mg/l and in three of these five samplings, the suspended
solids concentrations were above 130 mg/l. Each of these samplings followed a'rainfall
exceeding 0.5 inches . These higher suspended solid concentrations are indications o f
surface runoff.
The peak total phosphorus concentrations of Fanno Creek follow the 'suspended
solids peaks._ Major spikes were measured on August 21 and October 30, 1990 an d
during 1991 on June 20 and June 27 . The last three of these sampling days were als o
days of high flow in Fanno Creek . In addition to these dramatic spikes, there were a
number of samples during 1991 for which the total phosphate concentrations exceeded
0.2 mg/l (Figure 37) .
When the ortho phosphate concentrations in Fanno Creek during 1990 ar e
compared with those measured in Dairy Creek at the lower station, similar dry weather
6
flow values are measured . For 1991, however ; the Fanno Creek oro phosphate
concentrations exceed those measured in Dairy Creek (Figures 19 and 37) . The total
phosphate concentrations in Fanno Creek are consistently higher than those in Dair y
Creek including those sampling days on which there was no apparent surface runoff .
Kjeldahl and nitrate nitrogen concentrations throughout 1990 and 1991 ar e
essentially at the same level as those measured int he agricultural area except for a se-ries
of peak values noted at various times during the summer (Figure 34 and 38) . The higher
nitrate concentrations could result from groundwater inflow while the higher Kjeldahl
nitrogen concentrations are related to the entry of surface runoff and the processing o f
that runoff within the stream . One interesting observation in the Fanno Creek data is th e
unusually high ammonia nitrogen concentrations measured during May and June of 199 1
(Figure 39) . The cool, wet spring could have decreased the nitrification of ammonia to
nitrate .,
FORESTRY BASINS
Four sites with data collected by the Oregon Department of Forestry in 1991 and
at one site sampled during the early spring of 1992, was analyzed . The locations for
which data were compiled are as follows :
Gales Creek at Highway 6
This sampling point on Gales Creek is located in Sec 15-T2N-R5W and is th e
furthest downstream sampling point on Gales Creek but is still within the foreste d
area.
_
Gales Creek at Forest Park
This sampling point on Gales Creek is located in Sec 24-T2N-R6W and is locate d
well up into the watershed .
East Fork Dairy Creek at Fern flat Road
This sampling point, located well up in the basin, is in Sec 16-T3N-R3W . This
site has been sampled the past three summers and again in early spring 1992 .
Upper McKay Creek
This sampling point Sec 23-T3N-R3W is well up in the forested area on McKay
Creek.
7
The results from the Gales Creek samples are indicative of the various station s
within the forested area of the basin (Figures 41 through 45) . On Gales Creek at
Highway 6, the suspended solids concentrations were very low (less than 3 mg/1) . The
differences with time are probably not significant because at these low values, the
variability is largely associated with the difficulty of achieving precision at such a lo w
level. The concentrations are also low when compared with samples collected from th e
lower reaches of Dairy Creek or from the river which are typically greater than 8 mg/1.
The phosphorus concentrations at Gales Creek (Figures 43 and 45) are likewise
lower than the corresponding values from streams in the agricultural area . The
concentrations of both ortho and total phosphorus are uniform over time . Figure 43
indicates the average ortho phosphorus concentration to be 0 .026 mg/1 with a range of
0.021 to 0 .33 mg/1. The analysis sensitivity is about 0 .01 mg/1. These limited results
are consistent with flow of groundwater origin and with constant phosphorus content o f
inflowing groundwater .
The samples collected from the East Fork of Dairy Creek at Fern Flat Road tell
a similar story (Figures 46 through 51) . The suspended solids concentrations were lo w
but the total solids in 1992 were high (Figure 50) . The nitrate N concentrations are five
times higher (Figure 47) than those in Gales Creek and more similar to those lower i n
the Dairy Creek watershed . The total and ortho phosphorus concentrations are large r
than those measured in Gales Creek and show only slight variability . By comparing
Figures 46 and 48 with Figures 40 and 51 it is noted that when this site was sample d
again in March and April of 1992 the ortho phosphorus and the suspended solid s
concentrations were essentially unchanged from the summertime samplings of 1991 .
The Upper McKay Creek sampling station showed higher suspended solid s
concentration and considerably more variability than the three other forested stations .
Phosphate concentrations were the lowest of any of the sites (Figure 53) . The nitrogen
concentrations at this location were more similar to the Dairy Creek than to the Gale s
Creek station . Note the higher concentration of nitrate N early in the season, befor e
active vegetative growth is established, and a continually falling nitrate concentratio n
thereafter. The ammonia concentrations follow the opposite pattern, low during the early
8
summer but increasing during August. The maximum ammonia- concentration at thi s
sampling point reached 0 .19 mg/1 which is more than twice that measured at any of th e
other forestry sites . This higher ammonia concentration could result from decaying
organic matter on the stream bottom .
In total, these forestry stations suggest that the streamflow during the summer
moths consists of groundwater inflow . There was no surface runoff, hence, any impac t
of forestry management practices would not be evident on these samplings .
9
SUMMARY
This study was part of a larger effort to investigate the hydrology and wate r
quality dynamics of streams in the Tualatin River Basin . The ultimate goal is to identify
alternate strategies to improve water quality in the lower reaches of .the Tualatin River
during summer months. In order to do this, it is necessary to understand the source o f
water in the Tualatin River and identify the source of contaminants that promote th e
excessive growth of algae that currently plagues this reach of the river .
Precipitation, streamflow, and water quality data were studied in streams whos e
drainage basins were characterized as predominantly agricultural, urban or forested . In
all three land use areas, total solids concentrations were typically over ninety percen t
soluble. The concentration of soluble chemicals tended to vary little . Ortho phosphorus
concentrations varied from 0.03 to 0.10 mg/1.
The stream selected as reflecting an agricultural drainage basin showed n o
evidence of runoff during the summer months of 1990 and 1991 . Streamflow was noted
to be highly responsive to precipitation events whenever those events were sufficient t o
exceed the water storage capabilities of the soil . Total solids concentrations were
typically less than 120 mg/1 and always less than 160 mg/l .
The urban basin provided a slightly different picture . Again, the stream quality
was most often reflective of a groundwater _ fed stream . More frequently than the
agricultural basin, however, the quality reflected the presence of surface runoff . For
example, on three sampling dates in the summer of 1990, the suspended solid s
concentration typically less than 15 mg/1, increased to 50, 135 and 145 mg/1 in respons e
to a precipitation event. One similar event was noted in 1991 .
The forested watersheds sampled behaved more like the agricultural watersheds .
There was no evidence that runoff caused changes in quality . Suspended solids
concentrations were typically half those measured in the agricultural area . Phosphorus
concentrations, both ortho and total, were less than those measured in either th e
agricultural or urban land use areas, but there were major differences in concentration s
among the four sampling locations studied .
1.0
Figure 1
Precipitation 199 0
Hillsboro, Orego n
May Jun Jul Aug Sep Oct Nov De c
Month,
1990
11
Table 1
Precipitation during 1990
Hillsboro, OR
Hundredths of inches
Day
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Jan
31
10
5
23
12
51
158
110
91
65
2
0
11
0
0
17
0
0
0
0
0
24
30
5
0
78
22
38
111
55
7
Feb
46
24
1
25
8
42
21
57
4
21
3
28
12
0
10
37
7
0
0
5
17
0
0
0
0
0
0
0
M
M
M
Mar
0
0
0
31
9
1
22
27
0
5
13
22
0
19
10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Apr
0
0
0
0
0
0
0
0
0
0
9
1
0
0
0
0
14
1
2
45
1
3
30
1
7
1
21
21
12
1
M
May
0
0
0
0
0
0
0
T
0
0
3
2
0
1
20
0
0
1
0
11
7
33
67
10
6
2
17
8
10
4
9
Jun
2
1
26
10
11
2
22
3
0
54
4
0
2
0
0
0
5
0
0
0
0
0
7
0
0
0
0
4
2
0
M
Jul
0
2
27
0
0
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Aug
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5
16
0
0
0
21
2
0
3
3
0
1
0
56
0
Sep
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5
45
8
0
0
0
0
0
0
0
0
0
0
0
0
0
M
Oct
0
0
4
4
37
5
0
0
0
1
0
T
5
5
17
3
2
61
7
1
32
70
0
0
0
5
0
22
22
28
52
Nov
3
4
6
3
1
4
14
5
0
0
0
0
67
40
10
1
9
20
0
11
5
8
1
2
39
3
21
7
0
73
M
Dec
27
46
2
31
24
0
0
0
3
46
15
0
20
I
0
0
0
2
34
0
0
0
0
0
3
5
2
30
0
0
0
ti
12
Figure 2
Precipitatio n 1991
Precipitation
Hillsboro, Orego n
0 .9
0 .8
C
c0 0 .5'ca 0 : 4
0
ai
w
0_
a_
1-
.3- -0 .3--
0 .2.2 -
__
0 .1 .x --
0
Eiill~l
May
_~
1
_
IiRIRI ITRlilllih Ills ~~411I111IIILIRllll Illlill~lllllIIIII 11{~{Ilfllllllli(II
Jun
Jul
Illilllllill{11 4 111 111 1iilllllilIIIIIIlllllllkllkl l
Aug
Sep
Month, 1991
Oct
13
Table 2
Precipitation during 199 1
Hillsboro, OR
Hundredths of inche s
DAY
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
May
0
0
0
0
0
2
1
50
6
2
0
3
5
3
0
0
59
55
22
1
0
0
0
0
0
12
0
0
0
12
1
Jun July Aug
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
4
0
0
0
0
0
0
0
0
0
0
3
0
0
0
1
0
0
0
T
0
9
0
0
0
17
0
0
2
0
0
0
0
0
0
0
0
0
0
61
0
0
89
0
0
1
0
0
1
0
0
1
0
0
1
6
0
0
0
0
0
0
10
0
0
10
0
0
3
0
0
0
M
0
39
Sept
39
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
M
Oct
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
26
8
8
84
1
2
37
0
0
Nov De c
4
13
9
0
0
0
7
12
75
25
14 11 1
4
72
1
2
2
5
10
10
5
2
13
11
16
0
31
0
3
0
1
0
95
0
59
24
9
33
0
63
22
34
5
63
0
9
26
1
37
11
15
3
45
7
2
5
2
9
0
5
M
0
Figure 3
Dairy Creek at Hwy 8
Flow rates during 199 0
160
140
120
40
20
0
May
Ju n
Jul
Aug
Sep
Month, 1990
Oc t
( sjo )
15
O
O
N
O
MOH
Figure 4
0
0
10
O
(U!)
O
1]
O
uoiiM .Idiaaad
O
(11 15 w) C-zON
Figure 5
CO
CV
Q
Q
0)
T'
c'?
(I/6w) sp!los Irmo! `(s4o) nnol j
16
17
Figure 6
Dairy Creek at Hwy 8
Total and dissolved solids, 1990
160
140
-
0
0
40 20 0
-
r
May
rT
Jun
-~rrrrr r err
Jul
1-
Aug
Sep
Month, 1990
rrr
Oct
18
Figure 7
Dairy Creek at Hwy 8
Total suspended solids, mg/I, 199 0
May
Ju n
Jul
Aug
Sep
Month, 1990
Oct
Figure 8
Dairy Creek at Hwy 8
Total and ortho P, 1990
0.3
E
C
0
0 .25
0 .2
May
Jun
Jul
Aug
Sep
Month, 199 0
Total P
Ortho P
Oct
Figure 9
Dairy Creek at Hwy 8
Nitrate + Nitrite N Concentration, 199 0
1 .6
1 .4
z 0 .4 -
0 .2
May
Jun
Jul
Aug
Sep
Month, 1990
Oct
.2,1
Figure 1 0
Dairy Creek at Hwy 8
Ammonia N concentration, 199 0
0 .1 0.09 0 .08 0.07 -
0
)
E 0 .0
6
z
'c
-
0 .05
o
E 0 .04
E
< 0 .03
0 .02
0 .01
0
May
Jun
Jul
Aug
Sep
Month, 1990
Oct
Figure 1 1
Dairy Creek at Hwy 8
Kjeldahl N concentration, 1990
0.8
0.7
0.6
i
0.2
0 .1
0
May
r r r r
Ju n
r r r
Jul
1
r
r
r r
r
r
Aug
Se p
Month, 1990
r r
~
r
oct
23
Figure 1 2
Dairy Creek at Hwy 8
Fecal coliforms, No ./100 ml, 199 0
1200
E
0
0
1
0
z
E
0
1000
800 600
r r Jun
rrr Jul
r r
May
r
JiJ
Aug
Sep
Month, 1990
Oct
r
r
Figure 13
24
3H
0
0
-
0
LL
T
(s i o ) Mo
25
Figure 1 4
Dairy Creek at Hwy . 8 1990-9 1
120 -
0
H
20
I
60
I
I
i
80
100 120
Flow rate, cfs
f
140
1
160
i
180 200
26
Figure 1 5
Dairy Creek at Hwy 8
Flow rate, cfs, 199 1
200
180
160
140
120
100
80
60
40
20
0
fr1iffrf(fr(flffrf(f rfrr,rii)),,rJJ)ii)Ji))JI
11
f
11 [ 1
MAY Jun Jul Aug
Sep Oct Nov De c
Month, 1991
1
(U!)
27
UO1Mid!O0a d
co
a)
d'
N
Figure 1 6
a)
a
(Sp)
Mo N
I
28
Figure 1 7
Dairy Creek at Hwy 8
Total and dissolved solids, mg/I, 199 1
180
0)
160
140
120
100 80 60
40
20 0
I I I I I
T
MAY
11T T T
f
T
Jun
VT
FT T T
Jul
TI
T
f T I7 -f1
Aug
11 177 1
1
71
Sep
Month, 1991
T
T
T
TI
Oct
1
I I
I
I
111111
Nov
De c
I
I I
I
29
Figure 1 8
Dairy Creek at Hwy 8
Suspended solidsmg/I, 199 1
20
18
16
0
)
E
vi
14
12
0
u' 1 0
a)
-a
c
a)
U
8
6
4
2
May Jun
Jul Aug
Sep Oct Nov qec
Month, 1991
30
Figure 1 9
Dairy Creek at Hwy 8
Total and ortho phosphate, mg/I, 199 1
0 .6
0 .5
0 .4
0.3
0 .2
0 .1
Jo
4
46J))o)IIJJ11iiiiiiiiiiIJ11-JiIIII)i~ J, I)
MAY Jun Jul Aug
Sep Oct Nov Dec
Month, 1991
31
Figure
20
Dairy Creek at Hwy 8
Ammonia N concentration, mg/I, 199 1
0 .08
cr)
E
c
0
ca)
0.0 7
0 .06
r. .
0 .05
c 0 .04
0
0
z 0 .03
° 0 .02
E
Q 0 .01
0
1 I
1
f
I I I 1
1
I 1
i
I
i
1 TT I I I
f
r (( I I I (I I I I I I I' I I I I I I i'I 11
1
I
rl l
l l
l I I I I I I I
MAY Jun Jul Aug Sep Oct Nov Dec
Month, 1991
32
Figure 2 1
Dairy Creek at Hwy 8
Kjeldahl N concentration, mg/I, 199 1
1 .2
rrrrrrrrrrrrrrfirr
MAY
Jun
Jul
r
Aug
Sep Oct
Month, 1991
Nov Dec
33
Figure 2 2
Dairy Creek at Hwy 8
Nitrate N concentration, mg/I, 199 1
5
4 .5
4
3 .5
frr
rr
rt r
r
f-frr rr
f
IjTl t '
j
j )'fl fr
r rr
ti
MAY Jun Jul Aug
Sep Oct Nov De c
Month, 1991
34
Figure 2 3
Dairy Creek @ Hwy 8, 199 0
Flow and solids loads
May 90 Jun 90 Jul 90 Aug 90 Sep 90 Oct 9 0
Month, 199 0
Flow rate, cfs
TS, Thou lbs/day
TSS, Thou lbs/day
35
Figure 2 4
Dairy Creek @ Hwy8, 199 1
Flow and solids load s
May Jun
Flow rate, cfs
Jul
Aug
Sep
Month, 199 1
TS, Thou lbs/day
o ct
Nov
TSS, Thou lbs/day
Figure 2 5
Dairy Creek @ Hwy 8, 199 0
Phosphorus load s
May 90 Jun 90 Jul 90 Aug 90 Sep 90 Oct 90
Month, 1990
Total phosphorus
Soluble ortho P
37
Table 3
rts
'D
(CI
co.
co.
co
)
o
OD LO CO
(L)I's
0 0-
O
>
•
q
C3) M O C))
(p r U) `7 (
r N
(01-.
0) CO CO CO
OEI
(Cl
Oa -ss
0)
M
r
•
N
C ' ) U)
r r r
U)
U)
r
h-
U) O (0
CO
N
V
r r
U)
CO
'
'cl'
OD
U) CO
N
OQ
CO 0) M
tO M U)
(0 U) CO ' :t M N (0
M (0 (0 U) 10 ct O)
(0 U) N M O
CO (0 M U) C O
U) (0
CT) N M
r N h ~t M CO O
d N
N
O CO OD N- O N O
Cn N O O CO M
a U) CO N- N ~
(0
N N
NN
U)
C
•
N
N
N M LO CO
r
•
O O N- 0) U) CO
(0 0) v 0) CO Nt
U) (0 O
CC)
O
(0
N
U) CO
(0 0)
CO 0)
O M M tO
U) d'
~t
Cn
1--
D
n
N.
r
O M
,- O
C
(0
C O C ) ) C O O 1O r r N (0
0 N
it U r r
cO
2
O O O O O 0)
> C 0) C)
Q 4
.
-) Q CA
0
•
D
H .f
l
o
LL
cO
2
U
OD
ti C
CO
L0 ti
U) N U)
O) - M N U)
(O
CO 0) M
ti O U) r
CO r r
h [t N r r
N
U)
r
V
N
O
U
)
U)
r
r
1' f0.)
U)
CO (0 CO OD CO CO 0 )
U) CO M r r r C O
T
T
r r r
0) r
0) r 0) 0) 0)
j 135) 3 ' U
2-3 -3 1 CoO
r
0)
O
Z
38
Figure 26
(so)
mol d
a)
a
(U!) uo1121idiaaad
Figure 2T
Fanno Creek at Durham, 1990 .Flow rate, cfs
40
Figure 28
Fanno Creek at Durham, 199 1
Flow rate, cfs
90
80 70
60
50
40 30
May
Ju n
Jul
Aug
Sep Oct Nov De c
Month, 199 1
41
Figure 2 9
Fanno Creek at Durham, 199 0
Total and dissolved solid s
May
Jun
Jul
Aug
Month, 1990
TS, mg/I
Sep
TDS, mg/I
Oct No v
42
Figure 3 0
Fanno Cr at Durham Rd 199 0
Total Suspended Solid s
160 140 120 E
0) 100 0
Cl)
a)
c
a)
a
80 - x .
60 -
c) 4 0
20
May
Jun
Jul
Aug
Sep
Month, 199 0
Oct
43
Figure 3 1
Fanno Creek at Durham, 199 0
Total and Ortho Phosphorus
May
Jun
Jul
Aug
Month, 199 0
Total P
Sep
Ortho P
Oct Nov
44
Figure 3 2
Fanno Creek at Durham, 199 0
Kjeldahl and Nitrate Nitroge n
May
Jun
Jul.
Aug
Month, 199 0
Kjeldahl N
Sep
Oct Nov
NO3 + NO2
Figure 33
Fanno Creek at Durham, 199 0
Total and ortho phosphorus load s
AM-Xi
Jul
Aug
Month, 199 0
Total P
t atsit
rL
Sep
Ortho P
Oct Nov
46
Figure 3 4
Fanno Cr at Durham Rd 1990=9 1
120
I
30
I
40
I
50
Flow rate, cfs
I
60
I
70
I
80
90..
47
Figure 3 5
.
Fanno Creek at Durham, 199 1
Total and dissolved solid s
300
250
200 t
150
100
50 0
TT
May
T
i
l l 1
1
Jun
r rr i r i
Jul
I l l l l l
it~
~
1
T l I I
111
1
I I
11
1
1
1
I
i
I
r
I
I
Aug
Sep Oct NovDe c
Month, 199 1
IS, mg/I
TDS, mg/I
48
Figure 3 6
Fanno Cr at Durham Rd 199 1
Total Suspended Solids
May
Ju n
Jul
Aug
Sep Oct
Month, 1991
NovDec
49
Figure 3 7
Fanno Creek at Durham ; 1 .99 1
Total and Ortho Phosphoru s
0.5
0 .45
c0
a)
0 .4 ° .
0 .350.3
c0
0 .25-
0
0 .1 5
0
u)
0 .2 -
__
a 0 .1-- _
_
0 .05 --.~
0
_
~!~I1!
May
Jun
Jul
Aug
Sep Oct NovDe c
Month, 199 1
Total P
Ortho P
Figure 3 8
Fanno Creek at Durham, 199 1
Kjeldahl and Nitrate Nitroge n
1 .8
1 .6
E 1 4
c
0
.1 2
1
0.8
0.6
0
0.4
z 0 .2
0
f f
i
ri rT' r IOct NovDe c
F
May
Kjeldahl N
NO3 + NO2
51
Figure 3 9
Fanno Cr at Durham Rd 199 1
Ammonia N Concentration s
1
0 .9
E
c
o
a)
Co
0 .8
0 .7
-
0 .6
0.5
o
Z 0.4
'E 0 . 3
o
• 0.
2
E
<
0.1
0
s PAARIPn
May
Jun
i PSAI,PPP
Jul
Ip
wPh !JP;
Aug
Sep Oct
Month, 199 1
NovDe c
_52
.
Figure 4 0
Fanno creek at Durham, 199 7
Phosphorus loads
12 0
N
0
20 -
May
Jun
Jul
ml-ise-lme.pe. r. r-TLr.t, ,hJ,
Aug
Sep Oct NovDe c
Month, 1991
Total P
Ortho P
53
Table 4
N ' r. CD
~t N ~t M
0
CO (O M d 0)
V N
N
(O (O OO [r r O
CO
(O C') t.
r
L0.(O V CD0(O
d M N r r N CA
LO If)
M r N r r 0 >.
-0
O
>.
Y -o
a-
U) CO
N r N
N
T-
N
N r r CV 0
r T
O CO O O N- h
N CO U) If)
to
.Q
to
n
M
(O r
CD M r (O T- N
U) CO (O M CO_ U) Nl- 0)
OD
UM (O
O T- CV
r r
r CO N.
N U) CO M 0 0 0 (O
r U] r r r
O
TN N
N (O C()
N
T-
NrCO r
CO
U)
M 0 t` (0 O
N CT r r
N( N
0) U) N M 0
O ,^ [t r N
M
3 LO O .T-♦W
M
N
1-
to
♦T)
~
u)
CO CO T- I' to (O
C))
M O O) U)
▪ O I~ M (O
f~ O N N f~ N U) M
f~ r N (O CO r CO CO
LO I~ N N
. LO (O CO 1r M
to
U) r (O
N r
M CO
O 0
L_ U
0) CA N N CO M
U) M
f~ rr
3
CA
(O (O
CD (O
M
() U) M t1) to
N r
[f d'
3
T
F-
r
C
0
2
O) O O O) O) a)
>-.
j) N U
r
C
O
o)
V/
a) V!
CA
VJ
j
a) U O aa))
� ~~Q(AOZ 0
54
Figure 4 1
Gales Creek @ Highway 6 ; 199 1
Total Suspended Solid s
5/8
6/4
7/2
7/30
Date, 199 1
8/27
9/26
10/24
55
Figure 4 2
Gales Creek @ Highway 6, 199 1
Nitrate N Concentration s
0 .12-0. 1
0 .04 z
0 .02 -
5/8
6/4
7/2
7/30
8/2 7
Date, 1991
9/26 10/2 4
56
Figure 43
Gales Creek @ Highway 6, 199 1
Phosphorus Concentration s
0 .05
0 .045
0 .04
0 .035
0.03
0 .025
0.0 2
0 .01 5
0.0 1
0 .005
0
5/8
6/4
7/2
7/30
8/27
Date, 199 1
Total P
Ortho P
9/26 10/24
57
Figure 4 4
Gales Creek @ Forest Park 199 1
Nitrate N Concentrations
5/8
6/18
Figure 45
Gales Creek @ Forest Park 199 1
Phosphorus Concentration s
0.04 5
0 .04
0.035
0.03
0
0
0 .025
0 .02-
a
0 .01 5
0
0.0 1
0 .005
0
5/8
6/18
7/16
8/13
Date, 199 1
Total P
9/10
Ortho P
10/1 0
59
Figure 4 6
East Fork Dairy Creek, 199 1
Fern Flat Road
5/8
6/4
7/2
7/30
Date, 199 1
8/27
9/26
10/24
60
Figure 4 7
East Fork Dairy Creek, 199 1
Fern Flat Road
1 .6 -
7/2
7/30
8/27
Date, 1991
61
Figure 48
East Fork Dairy Creek, 199 1
Fern Flat Roa d
0 .08 0 .07 0 .06 0 .05 0 .040.030 .020 .01-0
5/8
6/4
7/2
7/30
8/27
Date, 1991
Total P
Ortho P
9/26 10/2 4
62
Figure 49
East Fork Dairy Creek, 199 1
Fern Flat Road
3.5
3
0 .5
0
5/8
6/4
7/2
7/30
Date, 1991
8/27
9/26
10/2 4
63
Figure 5 0
East Fork Dairy Cree k
Fern Flat Road
3/10 3/17 3/24 3/31 4/07 4/14 4/21 4/28
Date, 1992
64
. Figure 5 1
East Fork Dairy Cree k
Fern Flat Road
0 .040 .035 0.03 0 .025
0 .02 0 .015-0 .0 1
0 .005
3/10 3/17 3/24 3/31 4/07 4/14 4/21 4/2 8
Date, 1992
65
Figure 5 2
Upper McKay Creek, 199 1
Suspended Solids Concentration s
25 -
5/8
6/4
7/2
7/30
8/27
Date, 199 1
9/26
10/24
66
Figure 5 3
Upper McKay Creek, 1991- Phosphorus Concentration s
0 .04
0 .035
0.03
•
0 .025
0.02
•
0 .01 5
•
0.0 1
0 .005
0
5/8
6/4
7/2
7/30 8/27
Date, 1991
Total P
Ortho P
9/26 10/24
67
Figure 54
Upper McKay Creek, 199 1
Nitrogen Concentration s
5/8
6/4
7/2
7/30
8/27
9/26
Date, 1991
Nitrate N
Ammonia N
10/2 4
68
Figure 5 5
Upper McKay Creek, 1991
Chloride Concentration s
7/2
i
T
7/30
8/27
Date, 1991
9/26
10/24