WATER QUALITY STUDY:
 MIDDLE SNAKE RIVER
   FEDERAL WATER
   POLLUTION CONTROL
   ADMINISTRATION
   NORTHWEST REGION
   PORTLAND,OREGON

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             WATER QUALITY STUDY:
             MIDDLE SNAKE RIVER
                 Prepared by

              Danforth G. Bodien
             Working Paper No. 69
 Technical Assistance & Investigations Branch
         Office of Technical Programs
   United States Department of the Interior
Federal Water Pollution Control Administration
               Northwest Region
               501 Pittock Block
               Portland, Oregon

               February,  1970

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                         CONTENTS
INTRODUCTION	        1
   Background.	        1
   Authority.	*	        2
   Scope	        2
      Study Area	        2
      Study Time	        2
   Objectives	        4
   Acknowledgments.	        4

SUMMARY	        5
   Findings	        5
   Conclusions.	        6

STUDY AREA DESCRIPTION	        9

WATER USES	       11

WATER QUALITY CRITERIA	       15
   Standards	       15
   Other Criteria	       15

SAMPLING AND ANALYTICAL PROGRAM	       19
   Survey Data Selection	       19
   Sampling Point Selection	       19
   Sampling Procedures and Analytical Methods	       23
   Monitoring Program	       24

SAMPLING RESULTS AND DISCUSSION	       25
   Hydrology	       25
   Water Quality	       28
      Dissolved Oxygen	       28
      Temper atur e	       43
      Nutrients and Algal Productivity	       48
      Sulfates and Sulfides	       51
      Dissolved Nitrogen	       53

DEFINITION OF TERMS	       63

BIBLIOGRAPHY	       65

APPENDIX	       67
   Dissolved Oxygen and Temperature Monitoring  Data
      Table 1 -- Below Brownlee  Dam
      Table 2 -- Below Oxbow Dam
      Table 3 -- Below Hells Canyon Dam

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                         LIST OF FIGURES

Figure                                                      Page

  1.  Middle Snake River Study Area	      3

  2.  Isotherms, Dissolved Oxygen and Dissolved
      Oxygen Saturation Profiles for Station 1
      (Brownlee Log Boom)	     37

  3.  Dissolved Oxygen Profile for Oxbow Reservoir	     38

  4.  Dissolved Oxygen Saturation Profiles for Oxbow
      Reservoir	     39

  5.  Dissolved Oxygen Profiles for Hells Canyon
      Reservoir	     40

  6.  Dissolved Oxygen Saturation Profiles for Hells
      Canyon Reservoir	     41

  7.  Isotherms for Oxbow Reservoir	     46

  8.  Isotherms for Hells Canyon Reservoir	     47

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                        LIST OF TABLES

Table                                                       Page

  1.  Idaho Power Projects Data	      10

  2.  Estimated Distribution of Maximum Runs of Salmon
      and Steelhead Trout to the Study Area	      12

  3.  Standards of Quality for Snake River Waters	      16

  4.  Location of Sampling Points	      21

  5.  Average Monthly Discharges in cfs for Snake River
      in Study Area	      26

  6.  Spillage for Brownlee and Oxbow plus the Discharge
      at the Hells Canyon gauge	      27

  7.  Water Spilled in cfs, March,  April, and May 1969
      at Brownlee, Oxbow, and Hells Canyon Dams	     29

  8.  Storet Data-Weiser	     31

  9.  Storet Data-Brownlee	     32

 10.  Storet Data-Oxbow	     33

 11.  Storet Data-Hells Canyon	     34

 12.  Storet Data-Asotin	     35

 13.  Dissolved Oxygen Levels below Hells Canyon Dam....     44

 14.  Chemical Parameter Profiles for Study Area	     52

 15.  Analysis of Dissolved Gases 3/29/69	     55

 16.  Analysis of Dissolved Gases 4/10/69	     57

 17.  Analysis of Dissolved Gases 4/30/69	     58

 18.  Analysis of Dissolved Gases 5/22/69	     61

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                         INTRODUCTION







                          Background




     The water quality of the Middle Snake River is of vital




concern to both State and Federal agencies.  The reach from




Weiser, Idaho to the river's mouth has in the past several




years been the subject of several studies and investigations




relative to water quality and uses.  The use of particular




interest is the anadromous fisheries of the Snake and its




major tributaries, such as the Salmon River.




     A water quality study was initiated in July 1968 to




gather data in support of Department of the Interior testimony




presented before the Federal Power Commission license applica-




tion hearings on High Mountain Sheep Dam.  Unusually heavy




rainfall during August 1968 required a supplemental field




survey in August 1969.  This follow-up survey was further




justified by Secretary Hickel's request for a moratorium on




project construction in the Snake during which more studies




were to be undertaken.




     This report includes the data from the above mentioned




surveys as well as data from the Federal Water Pollution Control




Administration (FWPCA) Pollution Surveillance Branch, Northwest




Regional Office, the U.S. Geological Survey, and the Bureau of




Commercial Fisheries.

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                          Authority




     Section 5 of the Federal Water Pollution Control Act, as




amended, authorizes the Secretary of Interior to conduct




11. . .studies relating to the causes, control, and prevention




of water pollution."






                            Scope




Study Area




     The study area, illustrated in Figure 1, included the reach




of the Snake River from Weiser,  Idaho (River Mile 351.6) to the




mouth of the Clearwater River at Lewiston, Idaho (River Mile 139.3).




The main emphasis of the study,  shown as the shaded area in




Figure 1, was concentrated in the reach from the Brownlee Reservoir




log boom (River Mile 285.2) to Wild Sheep Creek Rapids (River




Mile 241.4) below Hells Canyon Dam.






Study Time




     The study consisted of two  phases.  The first phase involved




the installation of three continuous dissolved oxygen (D.O.) and




temperature recorders for a three-month period commencing in




July of 1968.  The second phase  involved four one-week surveys,




one each during the months of August, September, and October




1968 and August 1969.

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                                                       O   'O   JO  JO  40  SO
FIGURE 1   Middle Snake  River Study Area

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                           Objectives




     The objectives of the study were to define the existing




water quality conditions of the Middle Snake River and to




determine the overall effects of the three individual Idaho




Power Company projects (Brownlee, Oxbow, and Hells Canyon)




upon water quality.







                        Acknowledgments




     The assistance and cooperation of the Idaho Power Company




is gratefully acknowledged.

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                          SUMMARY







                          Findings




 1.  A 34 to 38 percent reduction in dissolved oxygen concentra-




tions was measured between inflow and outflow in Brownlee




Reservoir compared with essentially no change in either Oxbow




or Hells Canyon Reservoirs.




 2.  Measured dissolved oxygen levels from Brownlee Dam to Wild




Sheep Creek Rapids below Hells Canyon Dam were below criteria of




applicable water quality standards except where algal activity




was high.  During the summer months the major portion of water




in Oxbow and Hells Canyon Reservoirs had a D.O. concentration




ranging from 5 to 6 milligrams per liter (mg/1).




 3.  The increase in dissolved oxygen measured in the river below




Hells Canyon Dam was small, ranging from 0.9 to 1.4 mg/1 in a




six-mile reach.




 4.  Temperatures in each of the three reservoirs during the




summer months were uniform to a depth of approximately 150 feet.




A thermocline exists in Hells Canyon Reservoir below which the




dissolved oxygen measured was zero.




 5.  When looking at average annual temperatures, less than a




1  C. change was noted between inflow and outflow in any of the




three reservoirs.




 6.  Significant algal concentrations were noted in all three




reservoirs.

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 7.  A decrease in turbidity,  total phosphorus, and total kjeldahl




nitrogen concentrations was measured between inflow and outflow




in Brownlee Reservoir with no  apparent change between inflow and




outflow in Oxbow and Hells Canyon Reservoirs.




 8.  Essentially no change in  either orthophosphate or ammonia




nitrogen concentrations was measured between inflow and outflow




of the three reservoirs.




 9.  Moderately high sulfate levels ranging from 12 to 60 mg/1




exist throughout the study area with conversion to hydrogen sulfide




gas in areas with zero dissolved oxygen.




10.  Spillage at the three dams during the high spring flows of




1969 resulted in dissolved nitrogen concentrations as high as




135 percent.






                         Conclusions




 1.  The reduction in dissolved oxygen between inflow and outflow




in Brownlee Reservoir is due to a combination of organic solids




which settle out, creating an  oxygen-consuming benthic load, and




the decomposition of dissolved and suspended organics.




 2.  Reaeration in the 6 miles below Hells Canyon Dam is limited




as the travel time is short and only a small percentage of the




flow is exposed at the surface.




 3.  The total phosphorus and  total kjeldahl nitrogen removed




in Brownlee Reservoir were in  solids which settled out.

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4.  The discharge of waters from below the thermocline in




Brownlee and Hells Canyon Reservoirs is potentially toxic to




fish because these waters contain hydrogen sulfide and ammonia.




5.  The amount of dissolved nitrogen added through spilling is




a function of the flow and the depth of plunge in the pool.




6.  Water supersaturated with dissolved nitrogen returns to




equilibrium very slowly in impoundments.

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                       STUDY AREA DESCRIPTION







     The area considered in this study is a 213-mile section




of the Snake River extending from Weiser to Lewiston, Idaho.




In this 213-mile reach, the Snake borders three states:  Idaho




on the east, and Oregon and Washington on the west.  Major




tributaries include the Burnt, Powder, Imnaha, Salmon, and




Grande Ronde Rivers.  Ninety-three and one-half miles are




impounded behind three dams built and operated by the Idaho




Power Company.  Data relating to these three projects can be




found in Table 1.




     The physical characteristics of the study area are striking.




For the major portion of the 213-mile reach, the Snake River




flows through a steep-walled, rough-terrained, narrow canyon




which at its deepest point is over 5,500 feet deep.




     Climate of the Middle Snake region is classified as semi-




arid.  Rainfall averages 11 inches annually at Weiser and 13




inches at Lewiston, with less than one-quarter inch during




the summer months.  Annual temperatures average 51  F. at Weiser




and 52  F. at Lewiston with over 70 days of at least 90  F.  Pan




evaporation from the reservoirs averages 30 to 40 inches per year




with 80 percent of the total between May and October.  Winds in




the canyon generally blow downstream during summer months and




upstream during winter months.

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10
                              TABLE 1



                     IDAHO POWER PROJECTS DATA

Type of Dam
Year Completed
Location of Dam (River mile)
Reservoir Length (miles)
Reservoir Surface Area (acres)
Total Storage (acre-ft.)
Height of Dam (ft.)
Elev., Top of Dam (ft.)
Water Surface Elev., max.
Water Surface Elev., mi n.
Elev., Tailwater (ft.)
£ Elev., Penstocks (ft.)
Brown lee
Rock fill
1959
284
57%
15 ,000
1,470,000
395
2090
2077
1976
1805
1948
Oxbow
Rock fill
1961
271
13
1,145
57,500
205
1825
1805
1800
1688
1750
Hells Canyon
Concrete gravity
1968
247.5
23
2,400
167,200
330
1695
1688
1683
1475
1550

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                             WATER USES







     The present major uses of surface water of the Middle




Snake are power production, recreation, and fish and wildlife.




A small amount of irrigation is practiced along benches and




bottom land.




     Snake River waters are used for a variety of recreational




purposes.  Most of these activities are centered in the Lewiston




area, where two public bathing beaches are located.  Pleasure




boating and water skiing are also popular in this area.  Else-




where in the study area recreational uses are small due to




poor accessibility and remote location.  The three reservoirs




studied are sparsely used with Brownlee receiving the greatest




use.  However, these remote areas constitute important outdoor




recreational resources and legislation to set aside portions




of the Snake and/or tributaries as wild rivers has been proposed.




     The Bureau of Commercial Fisheries has made estimates of




the maximum runs of salmon and steelhead in the Snake River




system.  Table 2 lists the distribution of these fish in the




study area.




   ,  Fish activity in the study area is heavy.  The varieties of




species, listed in Table 2, are such that either up or downstream




migration is ongoing each month of the year.  In addition, all

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         12
                                      TABLE 2

                 ESTIMATED DISTRIBUTION OF MAXIMUM RUNS OF SALMON
                     AND STEELHEAD TROUT TO THE STUDY AREA a/
                                    Fall    Spring-Summer  Blueback
__.	Snake River Run	Chinook	Chinook	(Sockeye)   Steel head

Asotin Creek                                                             1,900
Grande Ronde River                             12,200                   18,200
Snake River
  China Gardens-High Mtn. Sheep     3,600
Salmon River                                   95,300        3,500       39,700
Imnaha River                          300       6,700                    4,600
Snake River
  High Mtn. Sheep-Appaloosa         1,100
  Appaloosa-Pleasant Valley         3,600
  Pleasant Valley-Hells Canyon     22,000
Hells Canyon Dam Fish Facilities   17,800       2,500                    6,500
Small Tributaries
  Imnaha River-Hells Canyon Dam    	   	600      	    1,300

        TOTAL                      48,400     117,300        3,500      72,200
a/  This table is based on data available since counting began
 at McNary Dam in 1954 and does not reflect the distribution
 that could occur within any section or tributary in any
 given year.
Data Source:  U.S. Fish and Wildlife Service

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                                                                 13
life stages of development are represented throughout the




year.




     Many factors of water quality affect the lives of anadromous




fish, including high temperature, low dissolved oxygen, dissolved




nitrogen supersaturation, and disease.

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                                                                15
                    WATER QUALITY CRITERIA







                          Standards




     In compliance with Section 10 of the Federal Water Pollution




Control Act, as amended, the States of Idaho, Oregon, and Washington




have established water quality standards for the Snake River.  A




tabulation of the standards criteria for dissolved oxygen,




temperature, coliform bacteria, and hydrogen ion concentration




(pH) is presented in Table 3.  The standards were established




to conform with the present and potential water uses of the




Snake River.




     As part of each state's water quality standards, a statement




of non-degradation is required by the Secretary of Interior.




This policy provides for the maintenance of existing quality when




that quality is higher than levels set in the established standards.







                           Other Criteria




     In addition to the standards presented in Table 3 other




parameters are important in maintaining water quality.  Some of




the more important ones in the Middle Snake are nutrients




(nitrogen and phosphorus) and dissolved nitrogen gas.




     Inorganic nitrogen and phosphorus are essential for the




growth of algae and aquatic plants.  To avoid excessive growths




these nutrients should be limited in concentration to 0.30 mg/1




and 0.01 mg/1, respectively, according to Sawyer.(8)

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                                                       TABLE 3
                                     STANDARDS OF QUALITY FOR SNAKE RIVER WATERS
                             (Established by the States of Oregon,  Idaho and Washington)
                       Coliform Bacteria
                       (maximum allowable,
                       where associated with
                       fecal sources)	
                                     Hydrogen Ion
                                     Concentrations  (pH)
                                     (allowable  range)
                                                  Dissolved Oxygen (DO)
                                                  (minimum allowable
                                                  concentrations)	
                                                  Temperatures
                                                  (maximum allowable)
Idaho
(river mile
  to 247)
139
Idaho
(river mile 247
  407.3)
Oregon
(river mile 172.0
  to 407.3)
Washington
(river mile 0.0
  to 172.0)
Average of 1000 organ-
isms/100 ml; 2400
organisms/100 ml in
20% of samples. Between
river miles 139 and 170,
average of 240 organisms/
100 ml.

Same as above.
7.0 to 9.0 (Induced
variation limited to
0.5 pH unit).
                                     Same as above.
           Average of 1000 organ-
           isms/100 ml; 2400
           organisms/100 ml in
           20% of samples.
           Median of 240 organ-
           isms/100 ml; 1000 or-
           ganisms/100 ml  in 20%
           of samples.
                          7.0 to 9.0
                          6.5 to 8.5 (Induced
                          variation limited to
                          0.25 units).
75% saturation at sea-
sonal low; 100% satu-
ration in spawning
areas during spawning,
hatching and fry stages
of salmonid fishes.
                        Same as above.
                        75% saturation at sea-
                        sonal  low;  95% satura-
                        tion in spawning areas
                        during spawning, hatch-
                        ing and fry stages of
                        salmonid fishes.

                        8.0 mg/1
68°F (2°F in-
crease when river
temperatures are
66° or less).
                          70°F ('2°F increase
                          when river tempera-
                          tures are 68°F or
                          less).

                          70°F (2°F in-
                          crease  when river
                          temperatures are
                          68°F or less).
                          68°F (when less
                          than 68°F the per-
                          missive increase,
                          "t", is limited by
                          the relationship
                          t=110/ (T-15), where
                          "T" represents the
                          resulting water tem-
                          perature).

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                                                               17
     Dissolved nitrogen gas is becoming an important water




quality parameter in the Snake and main stem Columbia Rivers




as the cause of highly fatal gas-bubble disease in fish.




Concentrations of dissolved nitrogen as low as 104 percent




saturation have been reported to cause gas-bubble disease in




fish,                                                     - =

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                 SAMPLING AND: ANALYTICAL PROGRAM




                     . Survey Data Selection






     During the formulation stage of the FWPCA study, two phases




of. field investigation were planned.  These involved the installa-




tion of continuous monitors for dissolved oxygen (D.O.) and




temperature plus one-week surveys which were planned for the




months of August, September, and October 1968.  August was




chosen as the month when the maximum effect of high temperature,




low flow, and high algal activity on water quality could be




observed.  The September and October survey times were chosen




to measure the rate and degree of change in water quality




leading up to fall overturn in Brownlee and Hells Canyon




Reservoirs.




     Because August of 1968 was unusually wet and cool, an




additional one week survey was undertaken in August of 1969.







                    Sampling Point Selection




     Of iM.in concern in the study was the effect of the three




Idaho Power projects on water quality.  Therefore, sampling




stations were established above and below the three dams.  In




addition, samples were collected from the turbine penstocks.  A




sampling station at Weiser was used as a control to assess




water quality entering Brownlee Reservoir.  Besides these




stations, others were established at approximately five-mile

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20
intervals on both Oxbow and Hells Canyon Reservoir.   At these




stations, as well as at the Brownlee  log boom station, samples




were collected in mid-stream,  at  depths of 3 feet,  15 feet,




and each 30 feet thereafter.  Below Hells Canyon Dam samples




were taken approximately every half mile so that any effect of




atmospheric reaeration on D.O. concentrations could be noted.




     A tabulation of the points sampled with a description and




location in river miles can be found  in Table 4.

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          TABLE 4



LOCATION OF SAMPLING POINTS
STATION NO.
1.
2.
3.
4.
5.

6.
7.
8.
9.
10.
11.-
12.
13,
14.
15.
16.
17.
18.
DESCRIPTION
Brownlee Dam log boom
Brownlee Dam penstock : . •:
Brownlee Dam tail race ,
Highway bridge below Brownlee
Dam
Oxbow Reservoir - Opposite
Idaho Powers Rest Station ^ mile
upstream of Jacobs Ladder Creek
Oxbow Reservoir at Sumner Creek
Oxbow Dam log boom
Oxbow Dam penstock
Oxbow Dam tail race
Highway bridge below Oxbow Dam
Hells Canyon Reservoir opposite
Homestead School
Hells Canyon Reservoir at Lime-
point Creek
Hells Canyon Reservoir at Leep
Creek
Hells Canyon Reservoir at Squaw
Creek
Hells Canyon Reservoir at Eagle
Bar - opposite substation
Hells Canyon Dam log boom.
Hells Canyon Dam penstock
Hells Canyon Dam tail race
RIVER MILE
285.2
285.0
284.8
284.0

280.0
277.0
273.7
273.5
271.0
269.7
265.8
261.7
256.9
252.7
249.4
248.2
248.0
247.8

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      TABLE 4 (CONT.)



LOCATION OF SAMPLING POINTS
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
Snake River - 50 yards below
Hells Canyon Dam
Snake River at Deep Creek
Snake River at USGS Gaging
Station
Snake River at Hells Canyon
Creek
Snake River - Halfway between
Hells Canyon and Stud Creek
Snake River at Stud Creek
Snake River - Halfway between
Stud and Brush Creek
Snake River at Brush Creek
Snake River - % mile below
Brush Creek
Snake River - near Barton
Heights
Halfway between Brush and Battle
Creek
Snake River at lower Warm Springs
Snake River at Battle Creek
Snake River - halfway between
Battle and Wild Sheep Creek
Snake River at Wild Sheep Creek
247.7
247.4
247.6
246.8
246.3
245.9
245.3
244.7
244.5
244.1
243.5
242.9
242.2
241.8
241.4

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                                                                  23
           Sampling Procedures  and Analytical  Methods


     Water samples were collected with  either  a  Kemmerer  or


Van Doren sampler.


     When water depth was less  than  50  feet, temperatures were


measured with a laboratory thermometer.   Samples  were  taken  from


the Kemmerer water sampler, placed in a plastic  beaker,  and  the


temperature recorded.  When depth was greater  than  50  feet,  a


fresh water bathythermograph (BT) was used  in  addition  to the


hand temperature measurements.


     Dissolved oxygen was measured in the  field  using  the


Alsterberg (Azide) modification of the  standard Winkler method.


Oxygen saturation levels were determined  using saturation tables


from the twelfth edition of Standard Methods and  were  corrected


for elevation above sea level.


     All additional samples were sent to  the FWPCA  Pacific Northwest


Water Laboratory (PNWL) in Corvallis, Oregon for  analysis.   Nutrient


samples were preserved with mercuric chloride  (HgC^)*  sulfate and


sulfide samples were preserved with  zinc  acetate  [ZnCC-jHnOp)^],


and samples for biochemical oxygen damand  (BOD)  analysis  were


iced before shipment to Corvallis.   After  arrival in Corvallis,

                                            o
BOD samples were incubated for  5 days at  20  C.

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24
     Turbidity samples were sent to the PNWL where they were

analysed using a Hach—  turbidimeter.
                       Monitoring Program

     Early in the study, continuous recording monitors for

dissolved oxygen and temperature were installed below each of

the three Idaho Power Projects.  The units installed were

composed of an Electronics Instrument Laboratory Dissolved

Oxygen Probe and two Rustrak Recorders.  These monitors were

installed at the end of July 1969 and were removed on October 16,

1969.  During this period many problems developed which prevented

obtaining continuous data.  However, the data obtained were

considered accurate since calibration checks were made every

two weeks or less.

     Data obtained from the three monitors were reduced from

the charts and tabulated.  These data can be found in the Appendix.
     — Use of product and company names is for identification only
and does not constitute endorsement by the U.S. Department of the
Interior or the Federal Water Pollution Control Administration.

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                  SAMPLING RESULTS AND DISCUSSION







                             Hydrology




     Flow data for the Snake River in the study area were  obtained




from USGS records.  Table 5 lists these data  for three periods:




water year 1969 (October 1968-September 1969), water year  1968,




and a 15-year average for water years 1953-1967.  The use  of




the gauging station below Pine Creek was discontinued in 1968




because of the filling of Hells Canyon Reservoir.  A station was




established below Hells Canyon Dam as a replacement.  The  flow at




this station should be very close to that measured below Pine




Creek since no major tributaries enter the Snake River between




these two locations.  Major tributaries below Hells Canyon,




such as the Salmon, Imnaha, Grande Ronde, Asotin, and Clearwater,




greatly increase the flow at the Clarkston gauge.




     As can be seen from Table 5, the average annual flows  for




the reach from Weiser, Idaho to Hells Canyon Dam are approxi-




mately 18,000 cubic feet per second (cfs).  High flows occur




during the months of March through June followed by low flows




during July and August.




     Data from Table 5 show the marked increase in flow during




August 1968 which was 12 to 20 percent greater than the 15-year




average for this month.  These high flows necessitated spilling




of water .at Brownlee and Oxbow Dams.  Table 6 shows the amount





of spillage and the discharge at the Hells Canyon gauge.

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                                                         TABLE 5

                              AVERAGE MONTHLY DISCHARGE  IN CFS FOR SNAKE  RIVER  IN STUDY AREA^/

                                                  Water  Years 1953-1967

     Station	Oct.    Nov.    Dec.    Jan.    Feb.   Mar.   April    May     June    July    Aug.    Sept.    Ave.

Snake River          14,610  14,010  15,080  15,360   18,300  19,120  21,190  23,620  23,540   11,170   11,160   13,050   16,720
at Weiser

Snake River          15,140  14,520  16,490  18,470   21,330  21,170  23,180  24,090  24,440   11,290   11,040   13,440   17,840
below Pine CreekH/

Snake River          26,330  27,940  32,250  31,180   39,780  44,010  75,740  124,500  124,500   41,680   22,570   22,730   50,970
at Clarkston (adj.)

                                                      Water Year 1968

Snake River          14,900  15,800  15,400  15,100   18,800  14,200  11,100  11,300  13,100   9,380   12,950   12,300   13,600
at Weiser

Snake River          -	-	   14.140   15,220   14,680
at Hells Canyon Dam

Snake River          26,100  30,800  31,100  33,200   55,400  44,060  44,610  74,650  93,170   31,140   25,170   26,500   42,840
at Clarkston

                                                      Water Year 1969

Snake River          14,200  15,900  16,200  24,100   25,600  29,700  39,000  28,700  19,000   10,800   10,500   13,300   20,500
at Weiser

Snake River          14,800  17,100  20,600  27,500   23,200  40,100  46,700  29,400  19,000   11,600   11,700   14,100   23,700
at Hells Canyon Dam

Snake River          31,300  39,100  37,000  55,300   48,300  62,600  117,000 143,000 86,900   33,700   20,500   21,400   58,000
at Clarkston
a/U.S.G.S. Data, subject to revision.
b/Snake River at Oxbow + incremental inflow from  Pine  Creek  and  ungaged  area  prior to  January  1968.

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                                    TABLE 6



SPILLAGE FOR BROWNLEE and OXBOW PLUS the DISCHARGE at the HELLS CANYON GAUGE a/
Date
August 1968
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28 .
29
30
31
September
1
2
3
4
5
a/ Idaho Power Data
Brown lee Spill
(cfs)

_
-
-
-
-
1,600
9,500
9,500
12,400
16,000
17,900
15,900
18,200
9,900
9,800
17,400
8,900
8,400
8,500
3,300

3,500
4,300
100
-
-

Oxbow Spill
(cfs 5

_
-
-
-
-
-
1,900
5,300
8,500
7,800
4,400
-
5,500
3,600
-
-
-
-
-
-

_
-
-
-
-

Hells Canyon
USGS Gauge
Discharge (cfs)

10,900
10,200
14,100
14,100
16,400
13,300
12,600
18,500
22,000
23,600
23,200
22,400
21,000
17,500
15,800
18,400
15,700
15,100
14,700
14,400

12,600
10,400
13,200
9,700
10,000


-------
28
     Assuming plug flow in Oxbow and Hells Canyon Reservoirs,




and using a flow of 10,000 cfs for the summer months, the




detention times for Oxbow and Hells Canyon Reservoirs are about




3 days and 8 day,s, respectively.




     Another item of interest in Table 5 is the large spring




flows for 1969.  These flows, which were 90 to 100 percent




greater than the 15-year average flow, were accompanied by




spilling at all three dams.  Table 7 lists the actual spillage




rates for the months of March through May 1969.  Associated with




this great amount of spilling was a dissolved nitrogen problem




which will be discussed in detail in a later section.






                          Water Quality




Dissolved Oxygen




     Of the parameters measured in the Middle Snake River Study,




dissolved oxygen (D.O.) was considered most important.  Dissolved




oxygen concentrations are critical relative to the water quality




standards which were established to protect the fisheries.




Linked closely with D.O. is temperature which will be discussed




in the next section.




     The first data evaluated for this report was collected




from March 1968 through August 1969 by the Pollution Surveillance




Branch, Northwest Regional Office, FWPCA.  Stations sampled on




the Snake River are located at Weiser; below Brownlee, Oxbow




and Hells. Canyon Dams; and near the mouth of Asotin Creek.  Data

-------
                    TABLE 7
WATER SPILLED IN CFS-MARCH, APRIL AND MAY, 1969
   AT BROWNLEE, OXBOW, AND HELLS CANYON DAMSi/

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
a/

Brown lee
36,205
38,203
35,173
28,750
19,938
37,154
31,260
26,875
34,219
24,760
29,708
15,931
29,063
29,675
33,729
36,979
34,883
39,938
22,266
16,146
26,250
33,958 .
32,478
30,833
33,021
28,854
26,666
28,496
40,000
44,666
46,604
Idaho Power
March
Oxbow '
8,115
18,938
12,188
7,656
2,656
15,000
113
5,000
11,701
6,953
8,500
13,188
10,387
10,688
12,000
12,000
13,875
15,229
10,064
1,333
6,545
18,000
14,304
13,385
13,802
8,615-
4,567
8,229
28,643
28,646
25,333
Data

Hells Canyon
7,400
7,400
7,400
7,050
2,250
11,500
7,849
3,750
3,750
3,750
9,750
14,750
14,750
14,156
11,500
11,500
11,500
12,463
3,329
-0-
1,885
4,500
10,354
' 7,250
8,500
2,396
-0-
6,635
15,000
15,000
17,452


Brownlee
45,000
47,969
46,125
45,000
46,667
50,000
36,250
48,750
44,166
41,458
45,000
49,688 '
52,500
47,746
42,146
• 44,292
39,167
' 37,708
36,854
40,240
' 38,000
36,250
34,520
31,375
35,781
25,404
26,357
28,233
25,510
19,735


April
Oxbow
29,458
28,229
26,806
31,365
34,042
39,000
19,399
29,438
24,388
20,208
23,625
33,698
31,042
2-5,792
25,250
22,375
16,708
14,438
14,250
22,177
15,420
14,187
14,583
14,028
15,229
12,458
10,000
6,250
6,000
9,208



Hells Canyon
20,000
19,500
18,000
18,667
17,875
17,000
17,000
17,000
17,000
19,333
21,000
21,000
21,000
21,000
21,000
21,000
14,446
8,000
'8,250
8,000
8,958
8,000
8,000
8,000
•3,954
-0-
-0-
-0-
-0-
-0-



Brownlee
21,933
18,573
7,510
8,281
12,396
27,710
40,000
36,822
38,490
35,000
38,333
31,146
24,792
18,750
25,000
20,771
22,813
25,833
21,563
22,313
24,167
5,000
-0-
-0-
3,073
3,315
-0-
-0-
-0-
-0-
-0-

May
Oxbow
7,250
7,934
-0-
-0-
-0-
9,167
15,781
16,458
16,875
15,000
17,500
14,313
4,938
3,614
4,542
5,250
4,833
5,917
6,365
4,396
5,041
-0-
-0-
-0-
-0-
1,146
-0-
-0-
-0-
-0-
-0-


Hells Canyon
. -0-
-0-
-0-
-0-
-0-
6,333
12,000
12,000
12,000
12,000
12,000
8,292
2, 300
2,300
2,300
2,300
2,300
2,300
2,300
2,300
767
2,979
3,400
3,260
5,854
.-0-
-0-
-0-
-0-
-0-
-0-


-------
30
from these stations are contained in Tables 8 through 12.  The




average annual D.O. levels were 10.9, 7.5,  8.8,  7.9, and 10.6 mg/1




for Weiser, Brownlee, Oxbow,  Hells Canyon and the Asotin stations,




respectively.  Summer D.O. values for the same stations average




9.5, 5.8, 6.9, 6.1, and 9.2 mg/1.  Comparison of the D.O."s




at Weiser and Brownlee shows  a 31 percent reduction annually,




and a 39 percent reduction during the summer months through




Brownlee Reservoir.  A slight increase in D.O. through Oxbow




Reservoir is offset by an almost equal reduction through Hells




Canyon Reservoir, leaving the D.O. concentration about the same




below Hells Canyon Dam as below Brownlee Dam.  Values for




Asotin show an increase over  those for the  Hells Canyon station.




This is due to atmospheric reaeration plus  dilution from high




quality tributaries such as the Salmon and  Imnaha Rivers.




     The first phase of the 1968-69 FWPCA field surveys involved




the installation of continuous recording monitors for D.O.  and




temperature.  These monitors  produced a considerable amount of




data which were reduced and tabulated for daily maximums,




minimums, and averages.  This tabulated data can be found in




the Appendix.  The data for the Brownlee monitor shows an




average D.O. of 5.2 mg/1 for  the days of record.  During this




period the daily average ranged from 1.6 to 10.1 mg/1.  Spillage




at Brownlee Dam, which commenced on August  17 and ended on

-------
      TABLE 8
STORE! DATA--WEISER
DATE
FROM
TO
68/03/19
68/04/03
68/04/24
68/05/23
68/06/05
68/06/24
68/07/24
68/08/08
68/08/21
68/09/04
68/09/18
68/10/01
68/10/16
68/10/30
68/11/13
68/12/03
69/01/08
69/02/05
69/03/11
69/04/08
69/06/26
TIME DEPTH
OF
DAY FEET
16
15
09
14
oo"
16
07
06
12
10
11
08
12
07
14
14
09
12
08
14
17
00
00
30
30
15
15
30
15
30
15
20
30
30
45
30
15
00
00
15
15
00
00010
WATER
TEMP
CENT
9.0
9.9
13.0
17.0
19.9
25.0
22.5
21.0
17.6
18.0
18.5
16.0
11.5
10.0
8.3
6.0
3.0
1.9
4.5
9.1.
18.6
00300 00301
DO DO
SATUR
MG/L PERCENT
14.1
13.3
12.2
11.0
9.6
12.0
8.1
8.0
7.8
10.3
10,8
9.4
11.2
9.9
10.3
12.2
12.3
12.3
11.9
10.1
14.2




112.0
154.0
99.0
95.0
87.0
117.0
123.0
101.0
110.0
94.0
94.0
105.0
98.0
95.0
99.0
94.0
162.0
00665 70507 00610 00625 00945 00070 31503
PHOS-T PHOS-T AMMONIA TOT KJEL SULFATE TURB COLIFORM
P-WET ORTHO NHS-N N $04 JKSN DLY ENDO
MG/L MG/L-P MG/L MG/L MG/L JU MF/100ML
0.10
0.09
0.04
0.16
0.08
0.16
0.19
0.28
0.28
0.16
0.14
0.17
0.09
0.08
0.15
0.06
0.12
0.13
0.10
0.30
0.02
0.042
0.026
0'.022
0.024
0.012
0.029
0.031
0.079
0.093
0.065
0.017
0.017
0.017
0.027
0.050
0.038
0.120
0.079
0.041
0.068
0.015

0.100
0.100K
O.'IOOK
0.080
0.050K
0.010K
0.080
0.040
0.040
0.005K
0.005K
0.005K
0.010K
0.010K
0.030
0.030
0.030
0.010K
0.070
0.040

0.700

0.900
0.700
1.100
1.200
1.000
0.900
0.900
1.200
1.000
0.730
0.600
0.700
0.300
0.500
0.500
0.400
0.700
1.100


38
37
36
44
38
39
51

44
50
45
55
54
48
44
28
17 -
38
42


7
9
8
18
17
35
30
15
5
6
3
2
16
1
15
15
10
41
27
310
383
4700
2900
2400
3100
2400
1 1900
13600
7200
1300
6000
3700
9400
100K
2800
6600
1100
16100
3200
1600L

-------
       TABLE  9
STORE! DATA—BROWNLEE
DATE
FROM
TO
68/07/23
68/08/06
68/08/13
68/08/21
68/09/04
68/09/18
68/10/01
68/10/16
68/10/30
68/11/13
68/12/04
69/01/08
69/02/05
69/03/10
69/04/10

69/04/15
69/04/29

69/05/22
69/06/26
00010
TIME DEPTH WATER
OF TEMP
DAY FEET CENT
07
14
14
16
11
14
11
15
10
17
08
15
14
20
15
16
10
07
07
08
19
00
15
45 0003
00
50
30
00
00
30
00
00
20
00
00
45 0001
00 0001
00
30 0001
55 0015
30
00
14.3
23.0
22.4
20.8
21.0
20.0
19.5
15.0
14.0
11.1
8.0
6.0
2.9
5.0
10.6
11.1
10.0
11.6
11.3
16.3
19.7
00300 00301
DO DO
SATUR
MG/L PERCENT
4.8
5.4
5.8
9.7
3.4
4.3
4.6
4.8
5.5
11.5
6.2
11.1
14.5
14.6
12.6
9.6
9.4
0.6
0.3
9.7
9.0
49.0
66.0

114.0
40.0
49.0
52.0
50.0
56.0
110.0
55.0
94.0
114.0
121.0


122.0


104.0
1Q4.0
00665 70507 00610 00625 00945 00070 31503
PHOS-T PHOS-T AMMONIA TOT KJEL SULFATE TURB COLIFORM
P-WET ORTHO IMHS-N N 504 JKSN DLY ENDO
MG/L MG/L-P MG/L MG/L MG/L JU MF/100ML
0.07
0.03
0.06
0.06
0.09
0.08
0.13
0.07
0.07
0.06
0.11
0.15
0.12
0.09


0.11


0.06
0.04
0.051
0.013
0.029
0.040
0.082

0.084
0.065
0.060
0.049
0.080
0.090
0.096
0.049


0.071


0.018
0.019
0.050K
0.020
0.140
0.060
0.090
0.035
0.055
0.010

0.010K
0.020
0.040
0.080
0.050


0.140



0.080
0.300
0.400
0.700
0.500
0.600
0.520
0.590
0.600

0.500
0.400
0.800
0.300
0.500


0.600


0.500
0.500
1
1

2
7

12
IK

IK
0.5
14
3
49 3


37 15


26 5
26 2



5

100K

80




100









-------
     TABLE 10
STORET DATA—OXBOW
DATE
FROM
TO
68/08705
68/08/13
68/08/21
68/09/04
68/09/18
68/10/01
68/10/16
68/10/30
68/11/13
68/12/03
69/01/08
69/02/05
69/02/11
69/03/10
69/04/10

69/04/15
69/04/29

69/05/22
69/06/26
00010
TIME DEPTH WATER
OF TEMP
DAY FEET CENT
18
19
18
13
17
12
17
11
19
19
16
15
15
19
14
15
11
08
09
10
19
15
05 0003
00
15
20
00
00
10
00
20
00
00
00
20
50 0001
15 0030
25
40 0015
00 0001
15
45
21.0
22.0
20.8
21.0
20.0
20.0
15.0
14.0 .
11.0
9.0
6.5
2.8

5.0
10.8
10.5
10.3
11.6
11.4
16.3
19.2
00300 00301
DO DO
SATUR
MG/L PERCENT
6.0
6.2
8.8
6.5
5.6
6.6
6.0
5.3
7.8
8.2
11.2
14.7

14.5
12.1
12.5
12.7
0.6
11.5
11.6
8.5
70.0

103.0
76.0
65.0
76.0
62.0
54.0
74.0
75.0
96.0
115.0

120.0


120.0


125.0
97.0
00665 70507 00610 00625 00945 00070 31503
PHOS-T PHOS-T AMMONIA TOT KJEL SULFATE TURB COLIFORM
P-WET ORTHO NH3-N N S04 JKSN DLY ENDO
MG/L MG/L-P MG/L MG/L MG/L JU MF/100ML
0.04
0.05
0.06
0.09
0.07
0.11
0.07
0.09
0.06
0.08
0.12
0.09

0.09


0.11


0.07
0.04
0.018
0.024
0.034
0.081
0.059
0.091
0.063
0.070
0.056
0.073
0.060
0.110
0.004
0.048


0.071


0.031
0.023
0.010
0.030
0.020
0.060
0.030
0.050
0.060

0.010K
0.010K
0.060
0.080

0.030


0.130



0.060
0.400
0.400
0.600
0.600
0.520
0.590
0.330

0.500
0.500
0.500
a. 400

0.400


0.800


0.500
0.300
1

2
13

15
IK

IK
0.5
13
4

49 5


37 15


28 4
25 3


100



115




130










-------
       TABLE 11
STORET  DATA—HELLS CANY0N
DATE
FROM
TO
68/07/24
68/08/06
68/08/14
68/08/21
68/09/Q4
68/09/19
68/10/01
68/10/16
68/11/13
68/11/30
68/12/03
69/01/08
69/02/11
69/03/10
69/04/10
69/04/15
69/04/28

69/05/22
69/06/26
00010
TIME DEPTH WATER
OF TEMP
DAY FEET CENT
14
08
15
20
15
09
14
16
18
12
17
17
16
18
14
08
19
19
12
21
00
30
15 0003
00
00
30
15
15
00
30
30
30
00
15
10 0001
00
00 0001
45 0001
15
00
21.7
18.0
21.0
19.9
21.0
18.7
20.0
15.5
11.0
14.5
9.5
6.5

5.1
10.5
9.3
11.2
11.5
16.7
18.9
00300 00301
DO DO
SATUR
MG/L PERCENT
7.0
5.4
5.0
5.6
7.3
4.7
6.4
5.8
7.6
5.9
8.2
12.0

13.4
12.0
13.0
11.4
0.5
12.1
7.3
83.0
60.0

64.0
85.0
53.0
73.0
60.0
72.0
60.0
75.0
102.0

111.0

124.0


131.0
82.0
'00665 70507 00610 00625 00945 00070 31503
PHOS-T PHOS-T AMMONIA TOT KJEL SULFATE TURB COLIFORM
P-WET ORTHO NH3-N N S04 JKSN DLY ENDO
MG/L MG/L-P MG/L MG/L MG/L JU MF/100ML
0.05
0.04
0.06
0.05
0.09
0.08
0.09
0.08
0.07
0.09
0.08
0.13

0.09

0.12


0.08
0.05
0.024
0.024
0.029
0.026
0.075
0.068
0.072
0.073
0.055
0.067
0.074
0.054
0.002K
0.052

0.066


0.026
0.021
0.050K
0.050
0.060
0.010
0.060
0.015
0.010
0.050
0.010K

0.030
0.060

.0.010

0.150



0.030
0
0
0
0
0
0
0
0
0

0
0

0

0


0
0
.400
.400
.500
.500
.500
.460
.780
.600
.600

.500
.600

.500

.500


.300
.400
IK
1

2 155
10

z
IK 660
IK

0.5
13

49 4

31 12


28 3
24 5

-------
      TABLE  12
STORE! DATA—ASOTIN

DATE
FROM
TO
69/02/12
69/03/12
69/04/03
69/05/14
69/06/11
69/07/09
69/08/04
69/08/26

TIME DEPTH
OF
DAY FEET
11 50
10 55
12 30
16 15
10 10
12 00
20 30
11 45
00010
WATER
TEMP
CENT

4.2
8.8
11.9
15.5
19.5
21.3
22.0
00300
DO

MG/L
12.6
13.2
11.4
10.8
9.5
9.6
8.9
8.7
00301
DO
SATUR
PERCENT


100.0
102.0
97.0
106.0
102.0
102.0
00665
PH'OS-T
P-WET
MG/L
0.12
0.09
0.16
0.10
0.12
0.03
0.06
0.05
70507
PHOS-T
ORTHO
MG/L-P
0.082
0.052
0.052
0.030
0.035
0.014
0.035

00610
AMMONIA
IMH3-N
MG/L
0.070
0.010
0.110
0.060
0.030
0.030


00625
TOT KJEL
N
MG/L
0.400
0.500
0.900
0.400
0.500
0.200


00945
SULFATE
S04
MG/L
28
39

15
12
17
22
37
00070
TURB
JKSN
JU
20
Z

13
10
IK
1
1
31503
COL I FORM
DLY ENDO
MF/100ML
1560
145
600
1430


1080
400L

-------
36







September 3, 1968, caused an average increase of 80 percent over




average D.O. values measured when no spilling occurred.  Data




from Oxbow Dam show a daily average D.O. of 6.1 mg/1 with a




daily average high of 9.0 mg/1 and a daily average low of




4.3 mg/1.  D.O. values at Oxbow Dam show an increase for




Brownlee which is due partially to the fact that the Brownlee




monitor ran 60 days compared with 48 at Oxbow.




     At the Hells Canyon station, 39 days of record were compiled.




During this time the average D.O. was 6.7 mg/1 with a daily




average high and low of 9.2 and 4.4 mg/1, respectively.




     Of interest at Brownlee was the great depression in D.O.




measured during the morning hours when high flows were needed




for power peaking.  The low values of D.O. can be seen most




dramatically for August 25 through 29, 1968, when daily minimum




averaged 3.3 mg/1, which was only 46 percent of the daily average




for the same period.




     During the four weeks of field surveys, D.O. and temperature




profiles were completed for Oxbow and Hells Canyon Reservoirs




plus a station located at the Brownlee log boom.  These profiles




are shown in Figures 2 through 6.  Figure 2 for Brownlee Reservoir




shows D.O. decreasing with depth for all four sampling periods.




The August 13, 1968, survey shows great increase in D.O. in the




top 30 feet which is due to algal activity.  Figure 2 also shows




the D.O. profiles in percent saturation.  Except f6r the areas

-------
FIGURE 2  Isotherms, Dissolved Oxygen and Dissolved Oxygen
          Station 1 (Brownlee Log Boom)
Saturation Profiles for

-------
FIGURE 3   Dissolved Oxygen Profiles for Oxbow Reservoir

-------
FIGURE 4   Dissolved Oxygen Saturation Profiles  for  Oxbow  Reservoir

-------
FIGURE 5   Dissolved Oxygen Profiles  for Hells Canyon Reservoir

-------
FIGURE 6   Dissolved Oxygen
           Reservoir
Saturation Profiles for Hells Canyon

-------
42
having high algal activity, the quality of water in Brownlee




Reservoir was below the Standards' minimum D.O. criteria of




75 percent saturation.  Figures 3 and 4 show the D.O. and D.O.




saturation profiles for Oxbow Reservoir.  These profiles show




that during the survey period the greater portion of the




reservoir had a D.O. level of 5 to 6 mg/1.  Only during the




August 1968 survey was a great difference in D.O. observed




between the surface and bottom waters of Oxbow Reservoir.  The




D.O. percent saturation profiles in Figure 4, like those for




Brownlee, show that the whole reservoir, except at the surface




near the face of the dam where algal activity was highest, was




below the standard of 75 percent saturation.




     Hells Canyon Reservoir had the greatest gradient of D.O.




values as can be seen in Figure 5.  This reservoir had a




thermocline which ranged from 100 to 175 feet deep, below




which the D.O. was zero.  As in Oxbow and Brownlee, algal




activity near the dam face caused D.O. values to exceed 100




percent saturation in the surface layers during the dry 1969




survey.  Only in this area did the water in Hells Canyon




Reservoir meet the D.O. Standard of 75 percent saturation.




The D.O. saturation profiles for Hells Canyon Reservoir are




shown in Figure 6.  During the study period, the majority of




the reservoir had a D.O. value of 5 to 6 mg/1.

-------
                                                               43
     Sampling was performed for a distance of six miles below


Hells Canyon Dam to see how long it would require low D.O. water


from Hells Canyon Dam to reach 100 percent saturation.  Only


six miles of river could be sampled as Wild Sheep Creek Rapids


was not navigable.  Table 13 contains the D.O. data obtained from


four trips below Hells Canyon Dam.  The range of D.O. increase


over the six mile reach was only 0.9 to 1.4 mg/1.  In two cases


of the four, the percent saturation at Wild Sheep Creek was


above the Standard of 75 percent.


Temperature


     Three approaches were taken to evaluate effects of the


three Idaho Power Projects on temperature.  These involved


sampling by the FWPCA Surveillance Branch, continuous monitors


below the dams, and temperature profile studies.


     Surveillance sampling was done at five stations in the


study area.  These were located on the Snake River at Weiser,


below Brownlee, Oxbow, and Hells Canyon Dams, and at Asotin


Creek.  Data for this sampling are provided in Tables 8 through 12,


Comparison of these tables shows that the annual temperature


averages 13.3, 14.0, 13.9, 14.7 and 14.7° C. for the stations


at Weiser, Brownlee, Oxbow, Hells  Canyon, and Asotin,

                                 o                            o
respectively.  An increase of 0.7   C. through Brownlee and 0.8  C.


for Hells Canyon Reservoirs is noted with essentially no change


in Oxbow Reservoir.  In 1968, summer temperatures for Weiser,


Brownlee, Oxbow, and Hells Canyon averaged 20.4, 20.3, 21.2, and



20.3  c. respectively.

-------
                                                TABLE 13
                             DISSOLVED OXYGEN LEVELS BELOW HELLS CANYON DAM
Station
Hells Canyon Tail race
Hells Canyon Creek
Stud Creek
Brush Creek
Halfway between Brush
Battle Creek
Wild Sheep Creek
River
Mile
247
246
245
244
& Battle Creek 243
242
241
.8
.8
.9
.7
.5
.2
.4
8/14/68
D.O.
mg/1 XSat,
4.8
4.7
5.8
6.3
6.2
6.4
6.2
56
56
66
73
72
74
72
9/18/68
D.O.
, mg/1 %Sat.
4

5
5
5
5
6
.9

.2
.7
.8
.9
.0
58

61
67
68
69
70
10/16/68
D.O.
mg/1 %Sat.
6.0
6.2
6.2
6.8
6.8
6.8
6.9
66
68
68
75
75
75
76
8/10/69
D.O.
mg/1 %Sat.
5.7
6.0
6.2
6.5
6.5
6.7
7.0
70
72
74
78
78
83
86
Increase in D.O.                             1.4     16      1.1     12       0.9     10        1.3     16
Total Distance                       6.4

-------
                                                                 45
     Over the total period monitored, 87 percent of the data

                                                        o
for all three stations showed a diurnal fluctuation of 2  C. or


less between maximum and minimum temperatures, and 83 percent

                                             o
of the data showed a diurnal fluctuation of 1  C." or less


between maximum and minimum temperatures.  Whereas D.O.'s below


Brownlee fluctuated considerably during power peaking at the


dam, no apparent change in temperature was noted.  Tabulated


data for the temperature monitors is provided in the Appendix.


     The data provided by t,he temperature monitors were verified


by running temperature profiles in the three reservoirs.  Figure


2 shows the temperature profile at the Brownlee Dam log boom.


Data from four different surveys show the top 100 to 150 feet of


the reservoir to be nearly isothermal.  A thermocline was found


at this station during the August and September 1968 surveys but


was absent during the October 1968 and August 1969 surveys.  The


thermocline was located in both instances at approximately 140


feet.  Figure 7 shows the isotherms for Oxbow Reservoir.  Except


for the August 1968 survey, temperature differences from water

                                  o
surface to bottom were less than 2  C.  No thermocline was


observed in Oxbow Reservoir which is only 105 feet deep.  The


isotherms for Hells Canyon Reservoir are shown in Figure 8.


This reservoir, like Brownlee and Oxbow, was found to be


nearly isothermal in the top 150 feet.  During all surveys a

-------
FIGURE 7  Isotherms  for Oxbow Reservoir

-------
FIGURE 8  Isotherms for Hells Canyon Reservoir

-------
48
thermocline was found at Hells Canyon which affected only a small




portion of the reservoir, as can be seen in Figure 8.




     From all the data evaluated it can be concluded that during




the summer months most of the water in the three reservoirs




was of approximately the same temperature; if a thermocline




existed, it was at least 140 feet below the surface.






                 Nutrients'and Algal Production




     There is direct evidence that waters of the Snake River




have high enough nutrient levels to support abundant growths




of algae.  Kari and Galloway report "great algal blooms in




most areas" between Adrian,  Oregon and Weiser, Idaho on




August 22 and 23, 1961. (7)   They also state: "The Snake River




carried an exceptionally heavy load of algae in suspension.




Dominant genera at the time  of the survey were Anabaena,




Pediastrum, Spirogryra, Aphanizomenon, Staurastruem, and




Anacystis." (7)  Three of the genera are "blue-greens" and are




indicators of enriched waters.




     Ebel and Koski report that "the large phytoplankton blooms




in Brownlee Reservoir throughout the summer indicated that high




turbidity did not seriously hinder primary production at the




surface." (5)

-------
                                                                49
     Area residents report that the second year after filling




seemed to be the worst as far as algal production was concerned.




The reports were partially verified for Hells Canyon Reservoir




which was relatively free of algal blooms in 1968 but which




had profuse growths in 1969.  A floating mat of blue-greens




two to three inches in thickness was observed at the downstream




end of the reservoir during the August 1969 survey.




     Algal growths cause aesthetic problems besides interfering




with recreational and municipal uses.  Another effect on




reservoirs that are rich in algae is that dead or dying algal




cells settle into the hypolimnetic (below the thermocline)




waters.  Decomposition of these cells consumes the D.O. supply.




Because there is no atmospheric reaeration and because there is




no photosynthetic activity at these levels, the D.O. concentra-




tions may go to zero.




     Algal-producing nutrients are becoming increasingly important




as water quality indicators.  As previously mentioned, the Snake




River in the study area supports abundant algal growths.  In




evaluating the effect of the three reservoirs on water quality,




nutrient transport and removal becomes important.  To accomplish




this, the year of data collected at Weiser and below each of




the three dams was evaluated.  Tables 8 through 11 contain this




data.

-------
50
     For the stations at Weiser, Brownlee, Oxbow and Hells




Canyon, respectively, annual concentration averages were:  total




phosphate .14, .08, .07, and .08 rag/1;  orthosphosphate .04, .06,




.05, and .05 rag/1; ammonia nitrogen .04,  .06,  .05,  and .04 mg/1




and total kjeldahl nitrogen .8, .5, .5, and .5 mg/1.  It is




interesting to note the 43 percent removal of  total phosphate and




3 percent removal of kjeldahl nitrogen  in Brownlee  Reservoir with




essentially no additional removal in Oxbow or  Hells Canyon




Reservoirs.  This can be explained by examining the turbidity




data which averages 15, 5, 6, and 4 Jackson Turbidity Units (JU)




for stations at Weiser, Brownlee, Oxbow,  and Hells  Canyon,




respectively.  The 60 percent removal of  turbidity  in Brownlee




Reservoir must be related to the total  phosphorus and kjeldahl




nitrogen removals, since these nutrients  are found  in suspended




organic solids.  The soluble orthophosphate and ammonia nitrogen




concentrations are not reduced, however,  as seen from a comparison




of Tables 8 through 11.  After the initial removal  of the nutrients




associated with the settleable organic  solids, little additional




removal can be expected.  It is also apparent  that  enough nutrients




exist in the soluble form to promote the  growth of  algae in




downstream Snake River reservoirs.




     During the August 1969 survey, samples were taken to see




how nutrient levels vary with depth in  a  stratified reservoir.

-------
                                                                51
Table 14 contains the data from this survey.  For the Eagle




Bar Station in Hells Canyon Reservoir, at depths of 3, 75, and




195 feet, respectively, total phosphates were 0..23, 0.08, and




0.10 mg/1, while orthophosphates were 0.031, 0.036, and 0.002




mg/1.  The high values at the 3-foot level were due to the




presence of algal cells.  Similarly, the kjeldahl nitrogen




values at the 3-foot level were 2.8 mg/1 compared to 0.4 mg/1




and 0.5 mg/1 at the 75 and 195-foot depths, respectively.  The




low value for kjeldahl nitrogen at the 195-foot depth indicates




minimal organic deposits on the bottom.  A significant deposit




would release ammonia and organic forms of nitrogen into the




overlying waters during decomposition.






                      Sulfates and Sulfides




     There is considerable concern over the possibility of large




fish kills due to hydrogen sulfide (H_S) production in the reser-




voirs on the Middle and Lower Snake River.  This production of




H~S results from the reduction of sulfate and sulfites to




sulfides under anaerobic (without oxygen) conditions.  The FUS




produced under these conditions is toxic to fish and aquatic life




at concentrations of 0.1 mg/1 as reported by Haydu, et al.(2,6)




H-S can also affect the use of water for domestic sources at




concentrations of 0.05 mg/1 or greater.




     In contrast to H-S, sulfates are relatively non-toxic;




however, a maximum concentration of 250 mg/1 has been set for

-------
                                                     TABLE  14

                                    Chemical Parameter  Profiles for Study Area

                                                   8/19 - 21/69
Station
Brown lee
Log Boom
Oxbow Log
Boom
Eagle Bar


Depth
Ft.
15
165
45
3
75
195
D.O.
mg/1
6.0
0.0
4.7
10.0
5.5
0.0
Sulfate
mg/1
60
44
60
52
56
26
Sulfide
mg/1
.14
.18
.12
.24
.12
.36
Total
Phosphorus mg/1
_
-
.23
.08
.10
Orthophosphorus
mg/1

-
.031
.036
.002
NH3-N N02-N NOo-N Kjeldahl -N
mg/1 mq/1 mq/T mq/1
— — _ ..
-
.04 .01 .08 2.8
.04 .02 .18 .4
.5
Wild Sheep  3
 Creek
7.0    52
12
.17
.032
.07
.02
.18
.4

-------
                                                                 53
sulfates in the U.S. Public Health Service Drinking Water




Standards.  This value was based on the potential laxative




effect to new users.




    Both sulfates and sulfides were measured in the Middle Snake




during the August 1969 survey.  The determination of sulfides




is not selective for H_S, but measures all forms of sulfides




(colloidal, soluble and gaseous).  Table 14 contains the results




of these analyses.  The level of sulfates in the upper strata




of the three reservoirs, as well as below Hells Canyon Dam,




ranges from 44 to 60 mg/1.  The sulfides also are fairly con-




sistent, ranging from 0.12 to 0.24 mg/1.  Because the upper




strata of the reservoirs contain dissolved oxygen, these sulfide




values of 0.12 to 0.24 mg/1 do not include any H2S but consist




only of soluble and/or colloidal forms. .The dissolved oxygen




at 195 feet at the Eagle Bar Station in Hells Canyon was




zero, however, and the samples collected had a strong odor of




H~S.  The presence of H-S was further verified by the reduction




of sulfates from 52 to 26 mg/1 and the increase in sulfides to




0.36 mg/1.  It therefore appears that H-S is a problem in Hells




Canyon Reservoir whenever dissolved oxygen is absent.






                      Dissolved Nitrogen




    Dissolved nitrogen (D.N.) super saturation in water, while




not a new phenomenon, is causing increasing problems relative




to fisheries.  The supersaturation of D.N. may lead to embolism




(gas-bubble disease) resulting in large fish kills.

-------
54
     Dissolved nitrogen supersaturation  seems  to occur  most




frequently below dams where excess  water which is spilled




entrains air in its mass and plunges  to  depths where  increased




static pressure causes a supersaturated  condition to  occur.




From data gathered it appears that  the time  required  for the




D.N. concentrations to return to equilibrium is fairly  long.




In the Middle Snake very little  change in D.N. was measured




from Brownlee to below Hells Canyon Dam, a distance which




required 3 days flow time at a discharge of  40,000 cfs.




     While it is agreed that D.N. supersaturation is  a  problem,




agreement cannot be reached either  on a  reliable method for




analysis or on a physiological threshold concentration.  Two




methods of analysis are presently being  used.   One uses a




Van Slyke gas blood analyses,(11) and the other a gas




partitioner.(9)  While the analytical difference between these




methods is not known, it probably is  less than that caused by




non-uniform sample preservation. A number of  threshold values




of D.N. have been reported, ranging from 104 to 120 percent of




saturation.




     During the spring of 1969 sampling  for  D.N. on the Middle




Snake was performed.  Four different  surveys were run,  one




by the Bureau of Commercial Fisheries (BCF)  and three by FWPCA.




Data from these four surveys are presented in  Tables  15 through 18.

-------
                                                    TABLE  15

                            Analysis of Dissolved Gases for the Middle Snake  River  a/

                                                March 29,  1969 b/
Location
Brown lee Dam/Forebay
Brownlee Dam Forebay
Oxbow Hatchery Intake
Oxbow Hatchery East
Pond
Oxbow Hatchery West
Pond
Hells Canyon Dam
Forebay
Grand Ronde
Depth
Ft.
10
30
Surface
Surface
Surface
Surface
Surface
Temp.
°C
8.0
7.6
8.0
8.2
8.2
7.4
7.7
D.O.
mg/1
9.8
13.6
13.7
12.1
12.2
13.3
12.3
.Nf/
mqVl
18.5
22.4
22.7
19.9
19.9
22.8
20.5
%N9
Sat.
104
116
118
104
104
117
106
a/  Bureau of Commercial Fisheries Data
b/  Discharge at Hells Canyon gauge 49,896 cfs.
£/  Analyzed by Van Slyke Gas Blood Analyzer ll/

-------
56-
     The first survey was conducted on March 29, 1969 by the




BCF.  Table 15 contains the data for this survey.  As can be




noted an increase in D.N. saturation can be seen from the




Brownlee forebay (104 to 116 percent) to the Oxbow Hatchery




(118 percent), which is located below Oxbow Dam at the head




end of Hells Canyon Reservoir.  Essentially no change in D.N.




saturation was measured in Hells Canyon Reservoir.  Table 7




shows that spillage for the days sampled was quite high




(40,000, 29,000, and 15,000 cfs at Brownlee, Oxbow and Hells




Canyon Dams, respectively).




     Table 16 contains data from the second survey on April 10,




1969.  This survey showed a substantial increase in D.N.




saturation, from 95 to 97 percent above Brownlee to 121 percent




below Brownlee.  A slight decrease is noted through Oxbow




Reservoir (114 to 116 percent above the dam).   From here to




below Hells Canyon Dam only minor changes were measured, with




a saturation value of 117 percent recorded at  the station below




the dam.  Spillage for the days sampled was about the same as




for the March survey (41,000, 10,000, and 19,000 cfs at Brownlee,




Oxbow, and Hells Canyon Dams respectively).




     The third survey was conducted on April 24 and April 30, 1969.




Table 17 contains the data for this survey. Very little change




is seen through Oxbow Reservoir and a decrease occurs at Oxbow

-------
                                                      TABLE  16
                               Analysis of Dissolved  Gases for  the Middle Snake River
                                                  April  10,  1969a/
Location
Above Brownlee Dam
Above Brownlee Dam
Below Brownlee Dam
Above Oxbow Dam
Below Oxbow Dam
Above Hells Canyon Dam
Above Hells Canyon Dam
Below Hells Canyon Dam
Depth
Ft.
Surface
30
Surface
30
Surface
Surface
30
Surface
Temp .
oc
11.1
10.7
10.6
10.5
10.8
10.7
10.5
10.4
D.O.b/
mg/1
9.6
9.4
12.6
12.5
12.1
12.0
12.0
13.0
%D.O.
Sat.
87
85
114
113
109
112
108
116
N2c/
mg/1
16.8
17.3
21.5
20.3
20.0
20.5
20.1
21.0
%N«
Sat.
95
97
121
114
112
115
112
117
Argon
mg/1
0.6
0.6
0.8
0.8
0.8
0.8
0.7
0.8
a/  Discharge at Hells Canyon  gauge  =  55,000  cfs.
b/  Field Analysis
£/  Analyzed with Gas Partitioner  9_/

-------
                                                      TABLE  17

                               Analysis of Dissolved  Gases for  the  Middle Snake River

                                                  April  30,  1969a/
Location
Above Brownlee Dam d/
Below Brownlee Dam
Above Oxbow Dam
Below Oxbow Dam
Above Hells Canyon Dam
Above Hells Canyon Dam
Below Hells Canyon Dam
Above Grande Ronde River
Depth
Ft.
15
Surface
15
Surface
Surface
30
Surface
Surface
Temp.
oc
11.3
11.6
11.6
11.4
11.5
11.5
11.2
10.5
D.O.b/
mq/1
9.7
12.3
12.1
11.5 §/
11.2
11.4
11.4
11.0
%D.O.
Sat.
89
113
111
106
105
104
104
97
N2c/
mg7l
17.5
20.2
20.0
18.4
18.8
19.2
18.7
15.8
S°a?.
99
115
114
-106
107
110
106
85
Argon
mg/1
0.6
0.8
0.8
0.7
0.7
0.7
0.7
0.7
a/  Discharge at Hells Canyon gauge =  29,900  cfs.
b/  Field analysis
c/  Analyzed with Gas Partitioner  9_/
d/  Sampled April 24, 1969,  Discharge  at  Hells  Canyon gauge = 40,500 cfs,
e/  Lab analysis

-------
                                                                59
Dam, going from 114 percent saturation above the Dam to 106




percent below the Dami.  Essentially no change is noted in Hells




Canyon Reservoir or over Hells Canyon Dam.  Of interest in this




survey is the drop in D.N. saturation from below Hells Canyon




Dam (106 percent) to the Grande Ronde (85 percent).  The distance




between these stations is 78 river miles, and two large tributaries,




the Salmon and Imnaha, enter in this reach.  Spillage for the




days sampled was reduced from the first two surveys (31,000,




9,000, and zero cfs for  Brownlee, Oxbow, and Hells Canyon Dams,




respectively).




     Table 18 contains the data for the final survey which was




conducted on May 22, 1969.  Data from this survey shows essentially




no change over Brownlee  Dam, but a big jump from the head of




Oxbow Reservoir (100 percent saturation) to the Dam (121 percent).




This change can be explained by looking at the spillage records




and noting that, on the  day sampled, the spillage at Brownlee was




only 5,000 cfs, but the  previous day's spillage ranged from




21,000 to 24,000 cfs.  Presumably the high D.N. above Oxbow




Dam was the result of the increase due to spillage at Brownlee




Dam for three preceding  days.  Essentially no change is noted




over Oxbow where no spillage was taking place.  This survey brought




out the large change noted over Hells Canyon Dam where the D.N.




saturation increased from 115 to 135 percent, with a spillage




of only 3,000 cfs.

-------
60
    In general, it can be concluded that the increase in D.N.




saturation due to spillage is a function of the depth of plunge




in the pool and amount of water spilled.  It is also shown that




the return to equilibrium is fairly slow, since no appreciable




change could be seen from one end of a reservoir to the other.

-------
                       TABLE 18
Analysis of Dissolved Gases for the Middle Snake River
                    May 22, 1969a/
Location
Above Brownlee Dam
Above Brownlee Dam
Below Brownlee Dam
Above Oxbow Dam
Above Oxbow Dam
Below Oxbow Dam
Above Hells Canyon Dam
Above Hells Canyon Dam
Below Hells Canyon Dam
a/ Discharge at Hells
b_/ Field analysis
c/ Analyzed with Gas
Depth
Ft.
Surface
30
Surface
Surface
30
Surface
Surface
30
Surface
Canyon gauge = 23,000
Parti ti oner 9_/
Temp.
°C
17.5
16.8
16.3
17.0
16.0
16.3
17.3
16.6
16.7
cfs.
D.O.b/
mg/1
12.1
8.9
9.7
11.8
11.0
11.6
11.0
10.5
12.1
%D.O.
Sat.
127
92
100
123
113
118
116
108
125
N2c/
mg/1
15.0
14.9
16.0
18.9
19.1
19.5
17.9
18.1
21.4
%N2
Sat.
100
94
100
121
119
123
114
115
135
Argon
mg/1
0.8
0.6
0.6
0.7
0.7
0.7
0.6
0.7
0.7

-------
                       DEFINITION OF TERMS


Algae--Simple plants, many microscopic,  containing chlorophyll.

Benthic Region—The bottom of all waters.

BOD--Biochemical Oxygen Demand.  A measure of the amount of
oxygen required for the biological decomposition of dissolved
organic solids to occur under aerobic conditions and at a
standardized incubation time and temperature.

cfs--Cubic feet per second.

Epilimnion--That region of a body of water that extends from
the surface to the thermocline and does  not have a permanent
temperature stratification.

Hypolimnion--The region of a body of water that extends from
the thermocline to the bottom and is removed from surface
influence.

JU--Jackson unit, a measure of turbidity which was derived from
a Jackson candle turbidimeter.

mg/1--Milligrams per liter (1000 mg/l=lgm/l)

Orthophosphate--A stable form of phosphorus which is the only
available form for biological activity.

Phytoplankton--Plant microorganisms, such as algae, living
unattached in the water.

Plankton--Aquatic plant and animal organisms of small size,
mostly microscopic, that have relatively small powers of
locomotion or drift in the water subject to wave action and
currents.

Reservoir Overturn--In deep lakes and reservoirs, the seasons
induce a cycle of physical and chemical  changes in the water
that are often conditioned by temperature.  For a few weeks
in the spring and again in the autumn water temperatures may
be homogeneous from the top to the bottom.  Vertical water
density is also homogeneous and it becomes possible for the
wind to mix the water, distributing nutrients and flocculent
bottom solids from the deeper waters.  This is a period of
water overturn.

-------
64
Thermocline--The layer in a body of water in which the drop
in tenderature equals or exceeds 1  C. for each meter or
approximately 3 feet of water depth.

Total Kjeldahl Nitrogen--0rganic nitrogen and nitrogen in the
form of ammonia £NHo)»  Does not include nitrogen in the form
of nitrates (NO- ) or nitrites (NO ~).

Total Phosphorus--Phosphorus in organic and inorganic forms.
Phosphorus and nitrogen are nutrients necessary for maintaining
biological growth.

-------
                          BIBLIOGRAPHY
 1.  Anonymous,  1968, Middle  Snake River Water Resources
    Development,  Snake River  Basin,  Oregon-Idaho-Washington, U.S.
    Department  of the Interior, FWPCA, Northwest Region, Portland,
    Oregon.

 2.  Anonymous,  1952, The  Effects of  Kraft Mill Waste Liquors
    and  Some  of Their Components on  Certain  Salmonoid Fishes of
    the  Pacific Northwest, National  Council  for Air and Stream
    Improvement,  Inc., Technical Bulletins,  No. 51.

 3.  Anonymous,  1968, Water Quality Control and Management--
    Snake River Basin, U.S.  Deparment of the Interior, FWPCA,
    Northwest Region, Portland, Oregon.

 4.  Brezonik, Patrick L., Delfino, J.J., and Lee, G. Fred, 1969,
    Chemistry of  N and Mn in  Cox Hollow Lake, Wisconsin, Following
    Destratification, Journal  of Sanitary Engineering Division,
    ASCE.

 5.  Ebel, Wesley  J.  and  Koski, C.H., 1967, Physical and Chemical
    Limnology of  Brownlee Reservoir  1962-64, Bureau of Commercial
    Fisheries Biological  Laboratory, Seattle, Washington.

 6.  Haydu, E.P.,  Amberg,  H.R.  and Dimick, R.E., 1952, The Effect
    of Kraft  Mill Waste  Components on Certain Salmonoid Fishes of
    the  Pacific Northwest, TAPPI, Volume 35, (12).

 7.  Kari, E.N.  and Galloway,  R.J., 1961, Summary Report Water
    Quality  Studies, Brownlee Reservoir--Snake River, Working
    Paper 16, Columbia Basin Proj.,  DHEW, PHS, Portland, Oregon.

 8.  Sawyer,  C.N., 1952,  Some  New Aspects of  Phosphates in Relation
    to Lake  Fertilization, Sewage and Industrial Wastes, 24, p.768.

 9.  Swinnerton, J.W. Linnerbom, V.J., and Check, C.H., 1962,
    Determiniation of Dissolved Gases in Aqueous Solutions by Gas
    Chromatography,  Analytical Chemistry, Vol. 344, p. 483-485.

10.   Symons,  James M., Weibel, S.R.,  and Robeck, Gordon G., 1964,
    Influence of  Impoundments on Water Quality, A Review of
    Literature  and Statement of Research Needs, Public Health
     Service  Publication, No.  999 WP-18.

-------
66
11.   Van Slyke,  D.D.,  Dillon, R.T., and Margaria, R.,  1934,
     Solubility  and Physical  State of Atmospheric Nitrogen  in
     Blood Cells and Plasma,  Journal of Biological Chemistry,
     Volume 106, p.  571.

12.   Wagner,  R., 1960, Water  Uses and Water Quality Interferences
     With Water  Uses — Snake River Basin, Working Paper No.  60,
     Department  of  Health, Education, and Welfare, USPHS, Portland,
     Oregon.

-------
                  APPENDIX



Dissolved Oxygen and Temperature Monitoring Data

-------
     TABLE 1
  MONITORING DATA
BELOW BROWNLEE DAM
DISSOLVED OXYGEN, mg/1
DATE
7/24/68
25
26
27
28
29
30
31
8/1/68
2
3
4
5
6
7
8
9
10
11
12
Max.
No Record
6.0
6.4
5.9
5.2
6.7
6.0
6.3
5.3
5.5
4.7
5.2
5.9
5.4
4.6
2.4
2.0
5.3
5.1
4.9
Min.

4.3
3.0
3.6
3.0
3.4
2.3
3.3
3.6
3.8
3.2
3.6
2.8
2.5
2.0
1.2
1.3
2.6
2.8
1.9
Ave.

5.3
4.8
4.9
4.8
5.3
4.8
4.8
4.3
4.3
3.9
3.9
3.8
3.3
2.6
1.8
1.6
4.1
3.8
4.4
TEMPERATURE ,
Max.
No
20
20
21
20
21
21
21
21
20
21
20
21
23
23
23
23
23
22
23
Min.
Record
18
16
17
17
16
16
16
17
17
17
17
17
22
18
18
19
19
19
18
uc
Ave.

19
19
20
19
19
19
19
20
20
20
20
21
22
23
22
22
22
21
21

-------
       TABLE 1
    MONITORING DATA
BELOW BROWNLEE DAM (Cont.)
DISSOLVED OXYGEN, mg/1
DATE
8/13/68
14
15
16
17
18 - 21
22
23
24 .
25
26
27
28
29
30
31
9/1/68
2
3
4
Max
6.9
5.9
6.2
Min..
1.9
2.4
4.9
10.1 4.1
10.2
No
9.6
9.6
9.6
9.2
9.2
9.3
9.5
9.5
No
No
No
No
No
3.4
10.1
Record
9.2
8.0
8.9
4.0
3.5
3.1
3.1
3.0
Record
Record
Record
Record
Record
2.3 .
Ave.
4.6
4.9
5.8
7.5
10.1

9.4
9.2
9.2
7.4
7.2
8.4
6.3
7.2





2.9
TEMPERATURE,
Max
23
23
23
23
23
No
22
22
22
22
22
21
21
21
21
21
22
21
21
21
Min.
19
19
21
22
21
Record
22
21
22
21
19
20
20
21
20
20
21
21
20
19
°C
Ave.
21
22
22
22
22

22
22
22
22
21
21
21
21
21
21
21
21
21
21

-------
                              TABLE 1
                           MONITORING DATA
                      BELOW BROWNLEE DAM (Cont.)
DISSOLVED OXYGEN, mg/1
DATE
9/5/68
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Max.
3.7
3.8
4.5
4.9
4.3
3.8
5.2
4.9
4.9
4.7
5.4
5.5*
5.5*
5.0*
4.3
5.0
9.0
9.2
9.2
9.4
8.9
Min.
1.3
2.0
2.8
3.9
2.8
2.9
3.0
4.0
3.2
3.7
3.1*
4.1*
3.8*
3.5*
4.2
3.5
3.6
9.2
3.6
9.0
3.7
Ave.
3.2
3.2
3.3
4.3
3.3
3.6
3.2
4.0
4.2
4.2
- 4.2
4.3*
4.5*
3.8*
4.2
4.1
7.5
9.2
7.6
9.0
7.1
TEMPERATURE,
Max
21
22
22
22
21
22
21
21
22
21
21
No
No
No
22
22
22
22
22
22
22
Min.
19
19
21
21
20
21
20
21
21
20
20
Record
Record
Record
21
22
22
22
22
21
21
UC
Ave.
21
21
21
21
21
21
21
21
21
21
21



22
22
22
22
22
22
21
*Estimates

-------
        TABLE.1
     MONITORING DATA
BELOW BROWNLEE DAM  (Cont. )
DISSOLVED OXYGEN, mg/1
DATE
9/26/68
27
28
29
30
10/1/68
10/2-17
Max
8.8
8.9
8.2
9.1
3.4
3.9
No
Min.
2.7
3.4
3.5
3.4
2.8
2.8
Record
Ave.
5.8
6.8
4.5
7.4
3.3
3.3

TEMPERATURE ,
Max.
22
20
20
20
20
19
No
Min.
20
20
19
19
18
19
Record
°C
Ave.
21
20
20
20
19
19


-------
   TABLE 2
MONITORING DATA
BELOW OXBOW DAM
DISSOLVED OXYGEN, mg/1
DATE
8/6/68
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Max.
6.1
6.7
6.3
6.0
6.6
6.0
5.6
5.8
6.7
6.0
6.6
6.6
7.0
7.5
No record
8.8
9.3
9.3
9.3
9.2
9.7
Min.
5.1
5.0
5.0
5.0
5.3
4.8
5.0
4.9
5.0
5.0
5.8
5.8
5.0
6.3

8.5
8.5
9.2
8.5
8.8
8.5
Ave.
5.1
5.6
5.3
5.4
5.5
5.0
5.2
5.2
5.8
5.4
6.2
6.2
5.8
6.6

8.5
8.8
9.2
8.9
9.0
9.0
TEMPERATURE,
Max
21
22
22
22
22
22
22
22
22
22
22
22
22
22
No
21
21
21
21
21
21
Mln.
21
21
22
22
22
. 22
22
22
22
22
22
22
22
22
record
21
21
21
21
21
21
°C
Ave.
21
21
22
22
22
22
22
22
22
22
22
22
22
22

21
21
21
21
21
21

-------
        TABLE 2
     MONITORING DATA
BELOW OXBOW DAM (Cont.)
DATE
8/27/68
28
29
30
31
9/1/68
2
3
4
5
6
7
8
9-18
19
20
21
22
23
24
.25
DISSOLVED OXYGEN, mg/1
Max . Min . Ave .
8.5 6.6 7.6
8.8 7.6' 8.0
8.8 7.5 8.0
8.5 7.6 8.0
8.3 7.5 8.0
7.8 6.8 7.2
6.8 5.1 5.9
6.4 5.1 5.8
6.8 5.9 6.3
6.8 4.8 6.0
6.0 4.2 5.2
5.6 3.8 4.3
5.6 4.9 5.2
No Record
No Record
No Record
No Record
No Record
No Record
No Record
No Record
TEMPERATURE,
Max.
21
21
21
21
21
21
21
21
21
21
21
21
20
No
22
21
20
20
20
20
20
Min.
21
20
20
20
21
21
21
21
21
21
20
20
20
Record
21
20
20
19
20
19
20
°C
Ave.
21
21
21
21
21
21
21
21
21
21
20
20
20

21
21
20
20
20
20
20

-------
       TABLE 2
    MONITORING DATA
BELOW OXBOW DAM (Cont.)
DISSOLVED OXYGEN, mg/1
DATE
9/26/68
27
28
29
30
10/1/68
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Max. Min.
No Record
No Record
No Record
No Record
No Record
No Record
5.3 4.5
5.2 4.5
5.2 4.6
5.3 4.2
4.9 4.2
5.3 4.9
5.3 5.0
5.7 5.0
5.3 4.6
5.3 4.6
5.5 5.1
5.8 5.1
5.8 5.2
6.0 5.5
5.6 5.4
Ave.






4.7
4.7
4.6
4.6
4.5
4.9
5.1
5.0
5.0
4.8
5.2
5.2
5.4
5.5
5.6
TEMPERATURE
Max.
20
20
19
19
18
18
20
20
20
20
19
19
18
18
18
18
17
>~17
17
17
16
Min.
19
19
19
18
18
18
20
20
19
19
19
19
18
18
18
18
17
17
17
17
16
, °c
Ave.
20
19
19
18
18
18
20
20
20
19
19
19
18
18
. 18
. 18
17
1-7
. 17
17
.., 16

-------
       TABLE 3
    MONITORING DATA
BELOW HELLS CANYON DAM
DATE
7/24-8/22/68
8/23/68
24
25
26
27
28
29
30
31
9/1/68
2
3
4
5
6
7
8
9
10
11
DISSOLVED
OXYGEN, mg/1
Max. Min.
No Record
8.4
8.7
9.3
9.6
9.1
9.6
9.6
9.6
8.9
8.5
No Record
8.2
7.5
7.8
7.7
7.3
7.3
7.2
7.0
6.1

7.2
8.4
8.7
8.7
9.1
8.7
8.7
8.7
8.7
8.2

8.2
7.2
7.3
7.3
6.8
6.8
6.6
6.1
5.2
Ave.

7.9
8.6
9.0
9.2
9.1
9.2
9.2
9.2
8.7
8.4

8.2
7:2
7.5
7.4
7.1
7.0
6.7
6.5
5.8
TEMPERATURE ,
Max.
No
20
20
20
21
20
20
20
20
21
21
No
21
21
21
21
21
21
21
21
21
Min.
Record
20
20
20
20
20
20
20
20
20
20
Record
20
21
20
20
20
20
20
20
20
°C
Ave.

20
20
20
20
20
20
20
20
21
21

21
21
21
20
20
20
21
21
21

-------
                                TABLE  3
                             MONITORING DATA
                      BELOW HELLS CANYON DAM  (Cont.)
DISSOLVED OXYGEN, mg/1
DATE
9/12/68
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
10/1/68
Max.
5.8
6.1
7.0
5.2
5.7
5.6*
5.4*
4.8
4.9
5.3
5.5
5.5
5.5
5.5
5.5
5.8
6.5
6.8
7.6
7.5
Min.
4.9
5.2
5.1
4.9
4.9
5.2*
5.0*
4.4
4.4
4.8
5.1
5.1
5.3
5.1
5.3
5.5
6.1
6.5
6.8
7.2
Ave.
5.2
5.4
5.4
5.0 ...
5.1
5.2*
5.2*
4.4
4.8
4.9
5.3
5.3
5.3
5.3
5.4
5.5
6.1
6.7
7.1
7.3
TEMPERATURE,
Max.
21
21
21
20
20
No
No
19
19
19
19
19
19
19
19
19
19
19
19
19
Min.
20
20
20
20
20
Record
Record
19
19
18
18
18
18
18
18
18
18
18
18
19
°C
Ave.
21
21
21
20
20


19
19
18
18
18
19
18
19
19
19
19
19
19
*Estimates

-------
          TABLE 3
       MONITORING DATA
BELOW HELLS CANYON DAM (Cont.)
DATE
10/2/68
3
4
10/5-16/68
DISSOLVED OXYGEN, mg/1
Max. Min. Ave.
7.5 6.8 6.8
No Record
No Record
No Record
TEMPERATURE,
Max.
17
16
16
No
Min.
16
16
15
Record
°C
Ave.
17
16
16


-------