WATER QUALITY EFFECTS of LOWER GRANITE DAM SNAKE RIVER LEWISTON, IDAHO - CLARKSTON, WASHINGTON U.S. DEPARTMENT OF HEALTH,EDUCATION, AND WELFARE Public Health Service, Pacific Northwest Region IX, Portland, Oregon ------- WATER QUALITY STUDY SNAKE AND CLEARWATER RIVERS A Report of Present and Post-Impoundment Water Quality Conditions Associated with Lower Granite Dam, Lewiston, Idaho - Clarkston, Washington Prepared for the Corps of Engineers U. S. Army Engineer District, Walla Walla Walla Walla, Washington U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Water Supply and Pollution Control Program, Pacific Northwest Region IX, Portland, Oregon ------- TABLE OF CONTENTS INTRODUCTION 1 ACKNOWLEDGMENTS 4 SUMMARY OF FINDINGS 5 CONCLUSIONS 8 RECOMMENDATIONS 11 THE RIVER SYSTEM 12 STUDY AREA 17 THE FIELD STUDY 18 WATER USES 19 Municipal Water Supply 19 Industrial Water Supply 19 Irrigation 20 Hydroelectric Power 20 Recreation 21 Fish and Wildlife 21 Waste Disposal 23 Water Transportation 23 SOURCES AND CHARACTERISTICS OF WASTES 24 COLLECTION AND ANALYSIS OF STREAM SAMPLES 31 Laboratory Analyses 32 INTERPRETATION OF LABORATORY RESULTS 34 Dissolved Oxygen 34 Biochemical Oxygen Demand 36 Chemical Oxygen Demand 40 Temperature and pH 40 Alkalinity, Hardness and Sulfates 42 Nitrates and Phosphates 43 Solids and Sludge Deposits 43 Bacterial Quality 46 ------- ii Page EFFECTS OF IMPOUNDMENT AND RESERVOIR OPERATION ON WATER QUALITY 50 Effects of Impoundment 51 Effects of Power Operations 60 FUTURE WATER USES 64 BIBLIOGRAPHY 67 ------- LIST OF TABLES No. Page I Summary of Waste Loads in the Lewiston-Clarkston Area . . 30 II Dissolved Oxygen Summary ..... 36 III Biochemical Oxygen Demand Summary 37 IV Chemical Oxygen Demand Summary AO V Temperature and pH Summary 41 VI Total Alkalinity, Hardness and Sulfates Summary 42 VII Nitrates and Phosphates Summary 43 VIII Total and Settleable Solids Summary 44 IX Bacteriological Analyses Summary 48 X Estimated Cross-Section Velocities and Travel Times for Lower Granite Reservoir with Average Discharge = 25,000 cfs 57 XI Estimated Reaeration Rates (K2 ) for Lower Granite Reservoir, August-September Conditions with Average Discharge = 25,000 cfs 59 LIST OF FIGURES 1. Survey Streamflows (Provisional) 16 2. Gaging and Sampling Stations End 3. Waste Source Locations 25 4. Dissolved Oxygen, Percent Saturation ..... 35 5. Sludge Bed Deposits 45 6. Estimated Density Current Profile 54 7. Velocity-Discharge Relationships under Natural Channel and Impoundment Conditions 55 8. Estimated Travel Times under Natural Channel and ------- INTRODUCTION This report presents information on present water quality conditions in the Snake and Clearwater Rivers in the vicinity of Lewiston, Idaho-Clarkston, Washington, and how changes in the streams' characteristics resulting from the construction of the proposed Lower Granite Lock and Dam Project by the Corps of Engineers will affect the water quality and waste disposal problems of that area. This dam is one of four similar structures to be constructed on the Lower Snake River to provide slack-water navigation between McNary pool on the Columbia River and the Lewiston-Clarkston area. These are: Ice Harbor Lock and Dam, already existing at River Mile 10; Lower Monumental Lock and Dam at River Mile 42; Little Goose Lock and Dam, at River Mile 70; and Lower Granite at River Mile 107.5, 32 miles downstream from the two cities of Lewiston-Clarkston which are located on either side of the Snake at its junction with the Clearwater River. The last three are all in various stages of construction. The Lower Granite pool will extend some four and one-half miles up the Clearwater and about seven miles up the Snake above the Clearwater junction. It will greatly alter several factors which control the waste assimilative capabilities of the streams. In order to better define these effects, the Walla Walla District, U. S. Array Corps of Engineers, after discussions with the U. S. Public Health Service, requested the Service to conduct studies to document ------- 2 conditions. The study was carried out by the Columbia River Basin Project for Water Supply and Water Quality Management, Water Supply and Pollution Control Program, Pacific Northwest, Portland, Oregon. The first phase of the study was initiated in March 1963 and con- sisted of the collection and analysis of such data on water quality and domestic and industrial wastes that were available in the files of the State water pollution control agencies of Idaho and Washington. Although very little data existed depicting current conditions, they were helpful in planning a field study to obtain additional informa- tion. This study was carried out over a three-week period in July and August 1963, the season when the combination of waste loads, low stream- flows, and high water temperatures exerts its most serious effects on water quality in this stretch of the stream. The study was designed to identify the water uses, the waste sources, points of waste discharge, diffusion patterns, stream hydrau- lics, deoxygenation and reaeration constants, and the physical and sanitary quality of the receiving waters. No attempt was made to determine the efficiencies of waste treatment facilities at the several waste sources, as the purpose of this survey was not to establish waste treatment requirements to meet present needs but rather to document present conditions and to define the water pollution problems and waste loading limitations that will exist when river characteris- ------- 3 is required to evaluate the impact of the proposed structure on other water uses and to assist appropriate authorities in establishing water ------- ACKNOWLEDGMENTS Grateful acknowledgment is made to the following for the assistance rendered: The Idaho State Board of Health and the Washington State Pollution Control Commission for making the results of previous studies available, and for their counsel and assistance in planning and carrying out this study; The City of Lewiston for making the city sewage treatment plant laboratory available for the use of the field chemists during the entire study period; The Walla Walla District, U. S. Army Corps of Engineers, for hydrologic data on the streams, for available design and operational data on the proposed impoundments, and for making the services of a boat and operator available for a major portion of the survey; Dr. W. V. Burt, Chairman, Department of Oceanography, Oregon State University, for information obtained from personal conferences and his studies on the dissolved oxygen and temperature characteristics resulting from proposed impoundments in the Snake and Clearwater Rivers, and the Bureau of Commercial Fisheries, U. S. Fish and Wildlife Service, for making these studies available; Other State and Federal agencies which were consulted on present and future water uses and water quality requirements for those uses; Potlatch Forests, Inc., for making it possible to introduce the ------- SUMMARY OF FINDINGS 1. Lower Granite Dam, now in the early stages of construction, is one of four similar Corps of Engineers projects on the Lower Snake River which will provide slack-water navigation between McNary Pool on the Columbia and the Lewiston-Clarkston area. This dam will create an impoundment extending up to and beyond the cities of Lewiston and Clarkston and will completely change the hydrologic characteristics of the Snake and Clearwater Rivers in this area, which are now turbulent, swift-flowing streams. Minimum flows in the Snake River below the Clearwater junction during the late summer months range from 18,000 to 25,000 cfs. Approximately 3,000 to 5,000 cfs of this is contributed by the Clearwater. 2. Additional authorized Corps of Engineers projects include Dworshak Dam on the North Fork of the Clearwater River approximately 40 miles above its junction with the Snake at Lewiston which is scheduled for completion in 1972 and Asotin Dam on the Snake immediately above the Lower Granite pool for which construction funds have not yet been appropriated. Power releases from these dams will also result in further changes in river hydraulics in the Lower Granite pool. 3. On the basis of studies conducted by the Public Health Service in July and August of 1963, the total organic waste as measured by the 5-day BOD reaching the Snake and Clearwater Rivers in the Lewiston- Clarkston vicinity was estimated to be 83,450 pounds daily. At least 86 percent of this load came from a single source; namely, the Potlatch ------- 6 4. The industrial waste discharged directly to the stream carried large quantities of suspended solids and highly colored dissolved solids. Due to the high stream velocities under present flow conditions, the formation of sludge banks on the stream bed was not extensive. Some visual evidence of industrial wastes was present in the vicinity of the pulp and paper mill and packing plant outfalls during the study period. Since the food processing plants were not in operation during the study period, no field observations were obtained regarding this waste source. 5. The municipal sewage treatment plants at Clarkston and Asotin, Washington, and Lewiston, Idaho, were operating satisfactorily and contributing a small fraction of the total waste load discharged to the streams. All three plants provide primary treatment with separate sludge digestion and disinfection of the plant effluent. 6. There was a high background BOD in the Snake River as it entered the study area. The probable cause of this condition is the relatively high concentration of algae in the stream as it enters the area. 7. The Snake and Clearwater Rivers in the study area have high reaeration rates. Because of this, the biochemical oxygen demand of the municipal and industrial wastes and the background organic load exert a very minor effect on the oxygen levels in the streams. 8. Slack water conditions in the Lower Granite pool will result in reduced stream velocities which will favor deposition of suspended solids and will reduce mixing of wastes. The reaeration rate of the ------- 7 photosynthetic-respiration effects of phytoplanktonic activity in the reservoir will be negligible. Consequently, the oxygen resources available for stabilizing the incoming wastes will be essentially limited to that amount of oxygen contained in the waters entering the pool. 9. At streamflows of 25,000 cfs, the travel time through the impoundment will increase over twenty-fold. This increased time will result in essentially all of the BOD of the waste load being satisfied within the impoundment^under minimum stream reaeration conditions. Under existing flow conditions, the reaeration rate is high and only a very small percentage of the demand is exerted within the time of ------- CONCLUSIONS The following conclusions are based on the data collected during this survey and on data and information obtained from other sources, particularly from the preliminary report prepared by Dr. W. V. Burt on the effects of impoundments on temperature characteristics of the Snake and Clearwater Rivers. The conclusions are presented as they relate to present and post-impoundment conditions. Present Conditions The quality of the Snake and Clearwater Rivers in the Lewiston- Clarkston area was in a generally satisfactory condition from a chemical standpoint at the time of this study. Bacterial levels below the points of waste discharge as measured during a special bacterial study in July of 1964 were slightly higher than recommended for water-contact sports such as bathing and water skiing. The fecal coliform counts were quite low indicating that chlorination of sewage treatment plant effluents is providing a relatively high degree of bacterial removal. However, there is a potential threat in the use of these waters for recreational purposes involving water-contact sports. Post-Impoundment Conditions 1. Lower Granite Reservoir can be expected to materially alter the hydraulic characteristics of the Snake and Clearwater Rivers and the rate at which organic matter will be stabilized by the natural purification processes within the stream. 2. The impoundment will create conditions which will be more ------- 9 diurnal variations in dissolved oxygen, with super-saturated values occurring during daylight hours followed by significant reductions in dissolved oxygen during nighttime hours. Algae growths also will degrade water quality for municipal and industrial use and may create objectionable conditions in the Clearwater arm of the impoundment from which the City of Lewiston derives its water supply. 3. It is anticipated that density currents will develop in the Lower Granite pool under summer conditions. The flow in these density currents will receive little reaeration. These conclusions are based on theoretical calculations and further study is essential to define better the complex relationships that may develop with the operation of this and other upstream and downstream reservoirs. 4. The flow releases from the Dworshak Dam on the Clearwater River and Asotin Dam on the Snake River will have a significant effect on the waste assimilative capacity and water quality in the Lower Granite pool. The highly variable flow conditions occurring under power-peaking operations of upstream hydroelectric facilities will create minimum flows which may permit the waste to concentrate around the waste outfalls, since there will be little stream movement and little opportunity for mixing. It is doubtful that longitudinal diffusion during peak flows will disperse these pockets of waste evenly throughout the reservoir. 5. Future operating schedules of Asotin Reservoir on the Snake ------- 10 may permit water from the Snake to flow upstream in the Clearwater arm of the Lower Granite pool. This could result in residual wastes from existing waste outfalls, at or near the confluence of the two streams, being carried upstream to the Lewiston water supply intake area. 6. The creation of slack water in the Lewiston-Clarkston area will be most favorable for greatly expanded recreational use of the area for water-contact sports. This will require an extremely high degree of bacterial removal in all sewage treatment plant effluents. Also, to minimize the loss of aesthetic values which might occur as a result of foam and color from the Potlatch Forests, Inc., operation, the waste outfall should be designed and located to produce the maximum diffusion and mixing of wastes with the incoming streamflow. Even with this precaution, color and foam during minimum streamflow periods may be objectionable to recreational uses. 7. Additional field data on actual reservoirs having similar characteristics are necessary to evaluate more accurately the effects of anticipated flows from upstream hydro-power operations on the quality ------- RECOMMENDATIONS 1. The Lewiston public water supply intake should be relocated to take water from above the existing Washington Water Power Company dam on the Clearwater River. 2. The point of discharge of wastes of the Lewiston Sewage Treatment Plant, Seabrook Farms Company, Potlatch Forests, Inc., and Bristol Packing Company, should be located a sufficient distance downstream from the mouth of the Clearwater River to remove the possibility of these wastes being moved upstream in the event of a flow reversal in the Clearwater arm of the reservoir. 3. Maximum possible degree of suspended solids removal should be provided for all waste sources of the area. 4. After completion of the Lower Granite Dam, additional studies should be carried out to determine the effects of the varying flows which may result from power plant operations on the temperature, dissolved oxygen, density current, and diffusion characteristics within the pool. Upstream installations should also be designed so that discharge rates and points of withdrawal can be adjusted to minimize ------- THE RIVER SYSTEM The Snake River above the Clearwater drains an area of 93,400 square miles. The upper portion of the drainage basin, from Jackson Lake in Wyoming to Weiser, Idaho, some 212 miles upstream from Lewiston, has been developed extensively for irrigation, and stream- flows are highly regulated. Downstream from Weiser, however, present water resource developments exert little effect on the streamflow patterns. The Payette, Weiser, Burnt, Powder, Imnaha, Salmon, and Grande Ronde are the principal tributaries entering the Snake in this stretch of the main stem. The terrain of these drainage areas is mountainous, varying in elevations from 730 feet above sea level at Lewiston to nearly 12,000 feet in the headwaters of the Salmon River in central Idaho. The streamflows in the Snake River at Lewiston follow a seasonal pattern of high flows from melting snows occurring during April, May, and early June, followed by rapidly diminishing discharges during June and July. Minimum flows occur from late July through September. Spring flows often approach 200,000 cfs, while average late summer flows usually range from 18,000 to 25,000 cfs. Average monthly flows for April, May, and June at the Clarkston gage (period of record, 1916 to 1960) are 79,570, 123,720, and 105,240 cubic feet per second. Average flows for the last week of July and for August and September are 23,640, 18,630, and 18,320 cfs, respectively. The minimum flow of record is 6,680 cfs. The flows from the Clearwater are included in ------- The Clearwater River, with a drainage area of over 9,600 square miles, drains the western slopes of the Bitterroot Mountain Range and lies between the Clark Fork-Pend Oreille River on the north and the Salmon River on the south. Rugged and densely forested mountains up to 9,000 feet above sea level comprise the eastern portion of the basin, while the western portion is sparsely timbered, with hills, plateaus, and small cultivated valleys. This stream also exhibits high spring flows and minimum late summer flows. Corresponding flows at the Spalding gage on the Clearwater (period of record, 1926 to 1950) are 30,892, 48,251, and 32,409 cfs for April, May and June; and 4,848, 3,224, and 2,846 cfs for the last week of July through September. The minimum flow of record is 500 cfs. As previously stated, the streamflows are not materially altered by impoundments or stream diversions on the main stem of the Snake or its tributaries between Lewiston-Clarkston and Weiser, Idaho. The only existing main stem developments are Oxbow and Brownlee hydro-power dams owned by Idaho Power Company. Oxbow Dam at River Mile 273, 133 miles upstream from Lewiston, forms a pool 11.4 miles long, extending to the tail waters of Brownlee Dam at River Mile 285. The Brownlee pool extends another 57 miles upstream, approximately ten miles below Weiser, Idaho. Other developments on the main stem of the Snake are being planned, however, and these can have significant effects on downstream flows and ------- River Mile 247, for which a license to construct has been granted to Idaho Power Company by the Federal Power Commission; High Mountain Sheep Dam at River Mile 189, just upstream from the mouth of the Salmon, also licensed by the Federal Power Commission to Pacific Northwest Power Company; and Asotin Dam at River Mile 145.6, at the headwaters of the Lower Granite pool, authorized for construction by the Corps of Engineers The flow of the Clearwater River is now relatively uncontrolled, the only control being the Washington Water Power Company's dam just 4.6 miles above the mouth of the stream. This installation maintains a flow of 4,300 cfs at capacity power production and, during minimum streamflow periods, may hold back essentially all of the streamflow during low power demand periods for release at times of peak demands. This development has a very minor effect on the streamflow regimen of the Snake River. Dworshak Dam now under construction on the North Fork and the proposed Penny Cliffs Dam on the Middle Fork of the Clearwater are authorized Corps of Engineers projects, with the former scheduled for completion in 1972. Funds for construction of the Penny Cliffs project have not yet been appropriated. The significance of the several proposed structures as related to the water quality problems in the Lower Granite pool will be dis- cussed in more detail under "Effects of Impoundments and Reservoir Operation on Water Quality." The streamflows in the Snake and Clearwater Rivers during the ------- 15 Clearwater) averaged 27,060 cfs during the first half of the survey and 23,120 cfs during the last half. The Clearwater flows were 5,465 cfs and 4,465 cfs for these same periods. These flows compare with the mean monthly flow for August of 19,300 cfs in the Snake River and 3,340 cfs in the Clearwater River and approach the mean annual low flows, the period when the most critical water quality conditions are ------- 40 35 30 co CLARKSTON GAGE SNAKE RIVER (Includes CLEARWATER) o o 220 S3 w ANATONE GAGE SNAKE RIVER" SPALDING GAGE CLEARWATER RIVER 28 29 30 31 SURVEY PERIOD 24 25 26 July August LOWER SNAKE AND CLEARWATER RIVER Vicinity of Lewiston, Idaho and Clarkston, Washington Survey Stream Flows (Provisional) (July 23 - Augsut 7, 1963) ------- STUDY AREA The study area (illustrated in Figure 2 at the end of this report) includes that portion of the Snake and Clearwater Rivers that will be impounded by Lower Granite Dam and extends from the dam site (River Mile 107.5) upstream to the Asotin dam site (River Mile 146.5) on the Snake and to the existing Washington Water Power Company dam on the Clearwater River, 4.6 miles above its confluence with the Snake (River Mile 139.5). Asotin Creek enters the Snake River at River Mile 145 just below the community of Asotin, Washington. No other streams of significance are within the study area. Lewiston and Lewiston Orchards on the Idaho side of the Snake, and Clarkston and Clarkston Heights on the Washington side, have a total population of approximately 31,000. Asotin, Washington, five miles to the south, has a population of 800 persons. This urban area serves as a service and distribution center for other communities and the rural populations of southeastern Washington and west-central Idaho. The economy of the area is built around lumber and forest products, agriculture, and food processing. The principal industries are: Potlatch Forests, Inc., a manufacturer of lumber, plywood, pulp, paper, and fuel products; Seabrook Farms Company, a pea and potato packer; and Smith Frozen Foods, a pea processor—all located in Lewiston; and Meats, Inc., and Bristol Packing ------- THE FIELD STUDY The intensive phase of the field study was carried out from July 22 to August 7, 1963. The objectives of the study were: 1. Determination of water uses; 2. Location and characterization of waste sources; 3. Determination of water quality and oxygen relationships under existing flow conditions; 4. Determination of diffusion patterns within the stream under existing flow conditions; 5. Determination of the presence or absence of deposits ------- WATER USES The Snake and Clearwater Rivers in the Lewiston-Clarkston area serve a variety of important uses. These include municipal and industrial water supply, hydroelectric power, recreation, propagation of fish and aquatic life and wildlife, a limited amount of irrigation, and waste disposal. The future impoundment of these waters will add navigation as a water use. Municipal Water Supply The City of Lewiston derives most of its domestic water supply from the Clearwater River. The intake and treatment plant is located at a point two and one-half miles above its confluence with the Snake. This point will be in the headwaters of the Lower Granite pool. Treat- ment consists of chemical coagulation, sedimentation, rapid sand filtra- tion, and chlorination. Because of its excellent quality, the Clear- water River will continue as the principal source of supply for this city. Ground water is the primary source of supply for Clarkston, its fringe area, and Asotin, Washington. Clarkston makes use of Asotin Creek as an auxiliary source of water supply which receives treat- ment consisting of sedimentation, coagulation, rapid sand filtration, and chlorination. Industrial Water Supply Potlatch Forests, Inc., uses over 40 MGD from the Clearwater ------- 20 at a point above the Washington Water Power Company dam. The industry will continue to use this source which is adequate to satisfy future industrial demands. The Clearwater is also used to transport logs to the mill from upstream timber areas and these are stored in the power pool of the Washington Water Power Company dam. Irrigation Small amounts of irrigation water are pumped from the Snake River below Lewiston-Clarkston. Primarily, this is used for sprinkler irri- gation of orchard and truck-farm crops grown on the narrow bottom lands along the stream. Most of these lands will be inundated by the impound- ment, and it is not expected that irrigation will create a major water demand with the raising of Lower Granite pool. Hydroelectric Power The Washington Water Power Company operates a 10,000 kilowatt hydroelectric facility on the Clearwater River. This power plant and dam is located four and one-half miles above the confluence of the Clearwater with the Snake. The Lower Granite pool will extend to the base of this dam, but will not interfere with power production. The proposed Lower Granite and Asotin Dams will provide power production as one of their beneficial uses. Lower Granite Dam will have a full power capacity of 810,000 kilowatts, half of which will be installed initially. The Asotin project will be a 384,000-kilowatt facility, ------- 21 Recreation The Snake River is presently used for a variety of recreational activities. Both Lewiston and Clarkston maintain attractive public bathing beaches on the Snake River within their respective city limits. Summer usage of these is estimated to be over 400 persons per day. Occasional swimmers and bathers are also to be found on several attractive but undeveloped beaches below the two cities. Water skiing and pleasure boating are popular activities. Several boat marinas along the Lewiston-Clarkston waterfronts support these pastimes. As many as 50 water skiers and an equal number of boaters can be counted on the river during a typical summer weekend. These activities, however, are pretty much restricted to two short stretches of the river at Lewiston-Clarkston where the waters are deep and wide. During the low summer flows, many of the remaining sections of the river are too shallow and turbulent for these sports. The quieter waters of the Lower Granite pool should offer increased attraction for these water-contact sports. The area of use is likely to extend further downstream. Fish and Wildlife Hunting and fishing are also important uses of the Snake and Clearwater Rivers in this area. Annually, many thousands of man- hours are spent in goose and duck hunting and fishing for steelhead, salmon and resident fish. The Snake River and its tributaries are well known as migratory ------- 22 the Pacific Northwest. Approximately 70 percent of the steelhead trout and 60 percent of the chinook salmon passing McNary Dam on the Columbia River enter and ascend the Snake River. A majority of these fish migrate to and past Lewiston-Clarkston to spawn in the upstream tributaries of the Snake River. During 1959-60, a record year for steelhead trout, an estimated 97,500 ascended the Snake River to Lewiston-Clarkston. Some 40,000 of these continued up the Clearwater River to spawn and the remaining number migrated further up the Snake to upstream tributaries. A record run of spring chinook salmon occurred in 1957 when 174,000 of these fish were estimated to have migrated to spawning grounds in the Snake River tributaries above Lewiston-Clarkston. In 1958, a record run of 37,000 fall chinook salmon reached the Lewiston-Clarkston area for spawning further upstream. In this run, an additional 5,000 were estimated to have spawned directly in the Snake River below Lewiston-Clarkston. Small runs of sockeye (blueback) and coho (silver) salmon also migrate in the Snake River. This stream, therefore, is of major significance to the Columbia River and Pacific Ocean fishery industry. The Snake River supports a diverse and well-established resident fishery. Included in this are game-fish populations of rainbow and Dolly Varden trout, white sturgeon, mountain whitefish, smallmouth and largemouth bass, black and white crappies, yellow perch, sunfish, channel catfish, and brown bullheads. Non-game fish include squawfish, carp, suckers, chiselmouth, chubs, shiners, dace and sculpins. ------- 23 Waste Disposal As discussed under "Sources and Characteristics of Wastes," the Snake and Clearwater Rivers receive significant discharges of domestic and industrial wastes from several sources at or near Lewiston-Clarkston. These are the only waste sources in the study area. In fact on the Snake River, no other significant sources exist for over 200 miles upstream. On the Clearwater River, several small communities located forty miles or more above Lewiston discharge domestic sewage treatment plant effluents to the river and its tributaries. These wastes are of minor significance to water quality in the Clearwater and Snake Rivers at Lewiston-Clarkston. Water Transportation Presently, the Snake River is not navigable except by small boats. Completion of the four Snake River dams between Lewiston-Clarkston and ------- SOURCES AND CHARACTERISTICS OF WASTES AIL the principal waste sources are located in the immediate Lewiston-Clarkston area. In Idaho, the Lewiston sewage treatment plant, the Potlatch Forests, Inc., pulp and paper mill, and the Seabrook Farms food processing industry contribute waste to the Clearwater and Snake Rivers. In Washington, the Clarkston sewage treatment plant and two meat packing plants, Bristol Packing Company and Meats, Inc., discharge wastes to the Snake. The Asotin sewage treatment plant discharges into Asotin Creek as it joins the Snake. The organic content of sewage and industrial wastes is expressed as biochemical oxygen demand (BOD) and population equivalent (PE). The BOD is a measure of the amount of dissolved oxygen consumed by biological organisms in the biochemical stabilization of organic matter in the stream. A common base is 0.167 pounds of five-day BOD per capita per day, the amount of oxygen used during that period of time to stabilize the organic matter in the wastes from one person. PE is the calculated population which would normally contribute the same amount of BOD per day as present in a particular waste. The locations of these waste sources are shown in Figure 3. The characteristics and significance of these are summarized as follows: 1. Lewiston Sewage Treatment Plant. This plant receives the wastes from the City of Lewiston, population 12,000, and from approxi- mately 1,000 persons living in Lewiston Orchards. Eventually, the wastes from some 7,000 of the latter's 10,000 population will enter ------- ) WASTE SOURCES A Lewiston Sewage Treatment Plant B Seabrook Farms Company C Potlatch Forests, Inc. D Bristol Packing Company E Clarkston Sewage Treatment Plant F Meats, Inc. G Asotin Sewage Treatment Plant VER E CLARKSTON WASHINGTON H Lewiston Water Supply Intake" rn A WASHINGTON WA TER POWER CO. DAM LEWISTON LEWISTON ORCHARDS ASOTIN WATER QUALITY STUDY WASTE SOURCE LOCATIONS SNAKE RIVER.LEWISTON.IDAHO USDEPARTMENT OF HE ALTH.EDUCATION a WELFARE PUBLIC HEALTH SERVICE JfiOJON ^PORTLANDjOREGON ------- 26 of industrial waste tributary to the municipal system. The treatment plant is located on the north bank of the Clearwater River 0.8 of a mile above its mouth. It provides primary treatment--sedimentation with separate sludge digestion—plus effluent disinfection with chlorine gas. It is a we11-maintained and efficiently operated facility and is designed so that secondary treatment units can be added in the future. It was placed in operation late in 1960. The wastes entering this plant are typical domestic sewage, with the usual commercial wastes originating within a municipality of this size, plus the seasonal discharge of pea cannery wastes from the Smith Frozen Foods Company. During the cannery season, the waste load from this source may equal or exceed that from the remainder of the city. Primary treatment will normally effect a 35 percent reduction in biochemical oxygen demand and essentially complete removal of settle- able solids from the raw wastes. On this basis, it is estimated that the organic load discharged to the Clearwater River from this source has an average population equivalent of approximately 8,400. This would be greater during the canning season. 2. Potlatch Forests. Inc. This company operates a lumber and plywood plant, a 650 ton/day pulp and paperboard mill, and a recently completed 50 ton/day tissue mill on the south bank of the Clearwater River just downstream from the Washington Power Company dam. Essen- tially all of the liquid wastes (40 mgd) from this operation, including ------- 27 is discharged through an outfall sewer to the Snake River. The wastes enter the river through a submerged, non-diffuser type outlet near the east shore of the stream just above its confluence with the Clearwater. Small capacity waste retention lagoons exist but were not being used at the time of this study. The wastes from this operation are typical of a kraft mill, with bleaching, and contain high concentrations of oxygen-consuming sub- stances and suspended solids. Based upon mill reports to the State water pollution control agency and limited sampling at the plant waste outfall, the BOD load from this source was estimated to have a popu- lation equivalent in excess of 400,000, with high concentrations of wood fibers. 3. Seabrook Farms Company. This industry is a food processing plant located on the south bank of the Clearwater adjacent to the business district of Lewiston. The industry processes and packages peas during a six-week campaign in June and July and processes potatoes for nine months beginning in August. The potato processing capacity is 150 tons per day. All wastes, including caustic peel wastes, are discharged untreated to the Clearwater a quarter of a mile above its junction with the Snake. At the time of this study, the pea processing season was just terminating and the potato processing had not commenced. Consequently, it was not possible to obtain representative analysis of the waste flows. Based upon the production figures, however, it is ------- 28 equivalent of 50,000 during the vegetable processing season. These wastes, of course, will be high in suspended matter. 4. Clarkston Sewage Treatment Plant. This plant provides primary treatment for the domestic wastes of the 6,100 population of Clarkston. This plant, an older but well-maintained and operated facility, provides primary sedimentation with separate sludge digestion and effluent chlorination. The treated wastes are discharged directly to the Snake River one mile below Clarkston. Lower Granite pool will partially inundate this facility and necessitate its relocation or protection by levees. The City of Clarkston has retained an engineering firm to study this problem. The wastes entering this plant are principally domestic sewage with the usual discharges from commercial establishments-- no significant industrial wastes are contributed to the system. Based upon the average efficiency of such a plant, it is estimated that the organic load discharged to the stream will have a population equivalent of approximately 4,000. 5. Bristol Packing Company. This meat processor is located in Clarkston and kills up to 50 head of cattle or 135 hogs daily. Screening of waste solids is practiced. Grease and paunch manure are collected for separate land disposal. Wash water, floor drainage, and kill-blood wastes are discharged directly to the Snake River. Based upon the animal kill at this plant, it is estimated that the organic load discharged to the stream has a population equivalent of ------- 29 which are not removed in the screening operations. This firm plans to build a waste stabilization pond for the disposal and treatment of its entire waste load. Such a facility would substantially reduce the organic waste load now discharged to the stream. 6. Meats. Inc. This plant processes an average of 55 head of cattle daily. Liquid wastes are screened. Grease and paunch manure are collected for land disposal. The screened liquid wastes, including kill-floor wastes, are discharged directly to the Snake River, two and one-half miles below Clarkston. It is estimated that the waste load from this plant will be approximately the same as that of Bristol Packing, namely a population equivalent of 3,000, with significant quantities of suspended matter. Lower Granite pool will partially inundate this plant and cause its relocation. 7. Asotin Sewage Treatment Plant. This plant receives the domestic wastes from the city's population of 800. Primary sedimenta- tion and effluent chlorination are provided. Effluent is discharged to Asotin Creek, a short distance above its confluence with the Snake River. The population equivalent of the waste load going to the stream is estimated at 500, with very little settleable solids. This plant site will be partially inundated by Lower Granite pool and the plant will have to be either relocated or provided with levee protec- tion. The City of Asotin has retained an engineering firm to study this problem. The estimated organic waste load entering the Clearwater and Snake ------- 30 TABLE I SUMMARY OF WASTE LOADS IN THE LEWISTON- CLARKSTON AREA Waste Load Per Day Source PE # 5-Day BOD Lewiston Sewage Treatment Plant 8,400 1,400 Potlatch Forests, Inc .... 432,000 72,000 Seabrook Farms Company .... 50,000 8,300 Clarkston Sewage Treatment Plant . . . . .... 4,000 670 Bristol Packing Company .... 3,000 500 Meats, Inc .... 3,000 500 Asotin Sewage Treatment Plant .... 500 80 Total 500.900 ------- COLLECTION AND ANALYSIS OF STREAM SAMPLES Twelve stream sampling stations were established on the Snake River and two on the Clearwater. The locations of these are shown in Figure 1 (last page of this report). The Clearwater stations were between the mouth of the Clearwater and the Washington Water Power Company dam. Two of the Snake River stations were upstream from the first waste discharge at Lewiston-Clarkston but below Asotin Creek, which receives the Asotin sewage treatment plant effluent. Nine stations were below the junction of the Snake and Clearwater Rivers. A special sampling station (14) was established near the Potlatch Forests, Inc., waste outfall at River Mile S-139.5. It was not possible to sample all stations during each sample run. Therefore, for the first seven days of the survey, samples were collected at Stations 1 through 6. Only the Snake River sta- tions were sampled during the last half of the survey and at less frequent intervals. Samples were collected at approximately six-hour intervals throughout the survey. Sampling schedules were so arranged that samples would be taken at all hours during the twenty-four hour period at the upstream stations during the first week and at each hour of the 6 a.m. to 6 p.m. period during the second week. All samples were surface, grab samples and, except for dissolved oxygen samples, were composites of from two to five samples taken at different points across the stream. Separate dissolved oxygen ------- 32 A limited number of bacteriological samples were taken at the mid-stream point at all stations except 2 and 13. Long-term BOD samples were taken at all stream stations. Laboratory Analyses The laboratory analyses were performed in the Columbia River Basin Project laboratory in Portland, Oregon, and at the Lewiston Sewage Treatment Plant laboratory in Lewiston, Idaho. The assist- ance of the City of Lewiston in making this excellent facility available for the duration of the study greatly expedited the con- duct of the field analyses. All sample handling, shipment, and analyses were carried out in accordance with the Eleventh Edition of "Standard Methods for the Examination of Water and Waste Water," 1960. The following analyses were carried out on samples collected in the study area: Chemical Measurements *1. Five-day biochemical oxygen demand (BOD) 2. Long-term biochemical oxygen demand 3. Chemical oxygen demand (COD) *4. Dissolved oxygen (DO) *5. Hydrogen ion concentration (pH) ^Analyses carried out in the field; all others at the Portland ------- 33 6. Sulfates (SO4) 7. Alkalinity (as CaCC^) 8. Hardness (as CaCOg) 9. Soluble ortho-phosphates 10. Nitrates Physical Measurements *1. Settleable solids 2. Suspended solids 3. Total solids *4. Temperature Biological Measurements—^ 1. Total coliform bacteria 2. Fecal coliform bacteria 3. Fecal streptococci bacteria 1/ Plans called for only a limited number of these analyses. * Analyses carried out in the field; all others at the ------- INTERPRETATION OF LABORATORY RESULTS Tables showing the individual analyses of the various water quality parameters are presented in the Appendix. Summary tables of the more significant water quality constituents appear as a part of the following discussions. Dissolved Oxygen Table II summarizes the dissolved oxygen (DO) data collected during the survey. It will be noted that the DO concentrations approach or exceed saturation values throughout the study area with only a slight depression below the waste discharges at Lewiston- Clarkston. The data also indicate that DO conditions in the stream are adequate for all known water uses under existing flow conditions. The data also show diurnal variations, indicating photosynthesis by the algae in the stream. Figure 4 depicts these patterns for the Snake and Clearwater Rivers. The Clearwater showed less diurnal fluctuation indicating a lower concentration of algae. This prob- ably accounts for the lower background level of BOD in the Clearwater as compared with the Snake River. The Snake River under present flow conditions has a relatively high reaeration rate; the coefficient of reaeration (K2) of the stream under existing flow conditions was calculated to be 0.344. The deoxygenation constants (K^) calculated from long-term BOD's ------- 120 115 110 /— 2 105 Upper Snake Section Middle Snake Section Clearwater Section NOON 24 HOUR PERIOD DISSOLVED OXYGEN, PERCENT SATURATION Clearwater, Upper Snake, and Middle Snake Sections ------- 36 to 0.113 with an average value of 0.08. This is within the expected range for a stream such as the Snake at this location. On the basis of the above calculations, the stream has a high capability for assimilating oxygen-consuming wastes without seriously depressing the DO levels in the stream. TABLE II DISSOLVED OXYGEN SUMMARY July-August 1963 Snake and Clearwater Rivers Station River No. of % Sat. of No. Mile Samples Maximum Minimum Average Average Clearwater River 13 CLW-2.6 17 8.6 6.7 7.2 81 12 CLW-0.8 54 9.4 8.0 8.5 94 Snake River 1 S-141.1 60 10.4 5.0 9.3 102 2 S-139.8 60 10.3 8.4 9.4 104 3 S-139.0 150 10.0 7.9 9.0 101 4 S-136.9 120 10.0 8.1 9.1 101 5 S-135.0 116 9.9 8.0 9.1 101 6 S-132.3 116 9.9 8.0 9.0 101 7 S-128.0 48 9.8 7.8 8.7 98 8 S-123.2 48 9.6 7.8 8.7 97 9 S-119.2 48 9.5 7.9 8.6 97 10 S-115.0 48 9.5 8.0 8.7 97 11 S-110.5 48 9.4 8.0 8.7 97 Biochemical Oxygen Demand Table III summarizes the BOD data collected during the survey. As previously indicated, the biochemical oxygen demand is a measure of the amount of dissolved oxygen consumed in biochemical stabiliza- ------- 37 oxygen exceeds the rate of oxygen replenishment, then the dissolved oxygen concentration in the stream may be reduced to a level that is inadequate to support desirable aquatic life or the aerobic stabiliza- tion process itself. The BOD of an organic waste, therefore, is a measure of its impact on the oxygen resources of a stream. Also, an increase in BOD below a waste outfall is a measure of the amount of wastes entering the stream. TABLE III BIOCHEMICAL OXYGEN DEMAND SUMMARY July-August 1963 Snake and Clearwater Rivers Station River No. of Five-dav BOD (me/1) No. Mile Samples Maximum Minimum Average Clearwater River 13 CLW-2.6 18 2.69 0.80 1.37 12 CLW-0.8 18 3.37 0.40 1.34 Snake River 1 S-141.1 19 4.70 1.83 2.96 2 S-139.8 20 3.68 0.91 2.21 3 S-139.0 29 3.44 1.08 2.00 4 S-136.9 30 3.30 1.48 2.12 5 S-135.0 29 3.06 1.50 2.36 6 S-132.3 27 3.30 1.40 2.13 7 S-128.0 12 8.90 3.40 5.67 8 S-123.2 12 6.40 2.60 3.88 9 S-119.2 12 5.60 2.40 3.48 10 S-115.0 12 5.50 2.10 3.46 11 S-110.5 12 4.30 2.18 3.12 Practically all surface waters display some background BOD. Even decaying vegetation carried into a wilderness stream may create a ------- 38 pounds of oxygen for each million gallons of water. As may be noted in Table III, the BOD of the Clearwater is slightly in excess of 1 mg/1, indicating a relatively low level of man-made pollution. The Snake River above the Lewiston-Clarkston area, on the other hand, had an average BOD of approximately 2.5 mg/1. This is consid- erably higher than would be expected in view of the fact that the nearest major source of pollution is over 200 miles upstream and above the Brownlee and Oxbow Dams. Although there are significant waste sources above these impoundments, the wastes would normally be stabilized during the time of passage through this unpolluted stretch of stream. It is known, however, that the significant algal blooms occur in the stream and particularly in Brownlee Reservoir. Such growths are probably stimulated by nutrients contained in the incoming flows. The algae exert a demand on the dissolved oxygen as they die off, and the products of decomposition are recycled into the flowing water to again stimulate algae production farther downstream. It should be pointed out that with a streamflow of 25,000 cfs the entire waste load entering the streams in the Lewiston-Clarkston area would exert an oxygen demand of approximately 0.5 mg/1, or only twenty percent of the background level measured during the initial study period. While this background BOD is not a critical factor in DO levels of the Snake River under present flow conditions, it will be a very important factor in maintaining desirable dissolved oxygen ------- 39 Seven stream samples collected over a four-day period during July 1964 from the Snake River above all waste sources in the Lewiston-Clarkston area showed five-day BOD values ranging from 0.86 to 2.0 mg/1, with a mean value of 1.31. This is more repre- sentative of what might be expected at this location. The higher values observed during the previous year cannot be discounted, how- ------- 40 Chemical Oxygen Demand Chemical oxygen demand is a measure of the amount of oxidizable organic compounds present in a given sample and is measured by a strong chemical oxidizing agent under specified conditions. Table IV summarizes the chemical oxygen demand data obtained during the survey. It will be noted that the variation in COD at the different stations closely parallels that for BOD. TABLE IV CHEMICAL OXYGEN DEMAND SUMMARY July-August 1963 Snake and Clearwater Rivers Station River No. of COD (mg/1) No. Mile Samples Maximum Minimum Average Clearwater River 13 CLW-2.6 13 4.9 12 CLW-0.8 12 6.7 Snake River 1 S-141.1 15 14.3 2.4 10.6 2 S-139.8 15 12.5 3.5 8.2 3 S-139.0 25 15.0 5.9 9.7 4 S-136.9 24 12.1 4.5 9.5 5 S-135.0 23 11.8 3.4 9.4 6 S-132.3 23 10.5 4.1 9.2 7 S-128.0 12 21.9 13.0 15.5 8 S-123.2 12 21.8 8.0 13.3 9 S-119.2 12 15.4 7.2 11.5 10 S-115.0 12 17.2 6.7 11.3 11 S-110.5 12 14.4 6.7 11.0 Temperature and pH Table V summarizes the water temperature and pH data obtained ------- 41 Clearwater Rivers ranged from 20.6 to 22.0 degrees Centigrade, with maximums ranging from 22.0 to 25.4 degrees C. These maximum tempera- ture levels are near the upper limits recommended for certain species of fish, particularly salmon and some species of trout. TABLE V TEMPERATURE AND pH SUMMARY July-August 1963 Snake and Clearwater Rivers pH Temperature Station River No. of No. of Average Maximum No. Mile Samples Average Samples °C °C Clearwater River 13 CLW-2.6 18 7.50 17 22.0 25.4 12 CLW-0.8 18 7.84 18 20.9 23.0 Snake River 1 S-141.1 19 8.60 20 20.7 22.5 2 S-139.8 20 8.67 20 20.6 22.0 3 S-139.0 30 8.47 30 21.1 23.5 4 S-136.9 30 8.51 30 21.0 22.5 5 S-135.0 29 8.54 29 21.0 22.5 6 S-132.3 29 8.48 29 21.0 22.5 7 S-128.0 11 8.27 12 21.5 24.0 8 S-123.2 11 8.38 12 21.5 23.5 9 S-119.2 11 8.41 12 21.5 23.5 10 S-115.0 11 8.35 12 21.5 23.5 11 S-110.5 11 8.44 12 22.0 23.5 The hydrogen-ion concentrations (pH) observed during the survey were within the ranges that would normally be expected. The pH of the Snake River was higher than the Clearwater, which no doubt re- sulted from the higher alkalinity and greater algal activity in the former stream. These pH values, however, are compatible with all present uses of these waters, including the propagation of fish and ------- 42 Alkalinity. Hardness, and Sulfates Table VI presents a summary of alkalinity, hardness, and sulfate analyses made during the survey. It will be noted that the hardness of the Clearwater is considerably less than that of the Snake and, as would be expected, the Clearwater contains less alkalinity. For these reasons, the Clearwater River is preferable to the Snake River as a source of domestic or industrial water supply. TABLE VI TOTAL ALKALINITY, HARDNESS, AND SULFATES SUMMARY July-August 1963 Snake and Clearwater Rivers *Total Alkalinity *Hardness Sulfates >ta. River No. of Avg. No. of Avg. No. of Avg. No. Mile Samples ma/1 Samples mg/1 Samples mg/1 Clearwater River 13 CLW-2.6 14 24.0 14 19.2 13 2.6 12 CLW-0.8 14 19.2 14 15.4 13 1.1 Snake River 1 S-141.1 16 85.2 16 87.4 15 19.3 2 S-139.8 16 85.0 16 87.5 15 18.1 3 S-139.0 15 62.3 15 62.2 24 13.5 4 S-136.9 15 72.0 15 74.6 14 14.7 5 S-135.0 15 72.5 15 73.6 14 14.8 6 S-132.3 15 70.9 15 72.4 14 14.7 7 S-128.0 -- -- 10 18.6 8 S-123.2 -- -- 9 S-119.2 — -- -- -- -- 10 S-115.0 -- -- -- -- 10 18.9 11 S-110.5 — -- ------- Nitrates and Phosphates The summary of these data, shown in Table VII, does not point to any abnormal water quality characteristics. TABLE VII NITRATES AND PHOSPHATES SUMMARY July-August 1963 Snake and Clearwater Rivers Station No. River Mile Nitrates No. of Samples Average me/1 43 Soluble Ortho-phosphates No. of Average Samples mg/1 Clearwater River 13 12 CIW-2.6 CUW-0.8 14 13 0.20 0.03 13 13 0.04 0.02 Snake River 1 2 3 4 5 6 7 8 9 10 11 S-141.1 S-139.8 S-139.0 S-136.9 S-135.0 S-132.3 S-128.0 S-123.2 S-119.2 S-115.0 S-110.5 15 15 14 14 14 14 1 0.04 0.04 0.04 0.04 0.04 0.04 0.00 0.00 15 15 14 14 14 14 12 12 0.04 0.04 0.05 0.04 0.05 0.05 0.06 0.06 Solids and Sludge Deposits The summary of the total and settleable solids data from the survey is presented in Table VIII. Here again, the lower concen- tration of total solids in the Clearwater River indicates that this ------- 44 On the basis of the stream samples, the increase in settleable solids below the Lewiston-Clarkston area is considerably less than measured in a waste sample collected from the Potlatch Forests, Inc., outfall.— TABLE VIII TOTAL AND SETTLEABLE SOLIDS SUMMARY July-August 1963 Snake and Clearwater Rivers Total Solids Settleable Solids Station River No. of Average No. of Average No. Mile Samples ma/1 Samples ml/1 Clearwater River 13 CLW-2.6 14 47 4 0.06 12 CLW-0.8 13 16 5 0.03 Snake River 1 S-141.1 15 140 4 0.07 2 S-139.8 15 132 2 0.07 3 S-139.0 22 101 24 0.12 4 S-136.9 22 124 24 0.14 5 S-135.0 20 118 5 0.11 6 S-132.3 20 108 5 0.12 7 S-128.0 7 120 -- -- 8 S-123.2 7 118 -- -- 9 S-119.2 7 114 -- -- 10 S-115.0 7 120 — -- 11 S-110.5 7 114 • • • • An attempt was made during the survey to determine the extent to which the settleable solids may be accumulating on the stream bed. Several small deposits were found at the locations shown in Figure 5, in the back-water zone of bank-side eddies where low velocities per- mitted their accumulation. In the high velocity waters of the main channel, sludge deposits were absent and clean stream bottoms prevailed. 1/ The sample indicated a loading of 101.5 tons per day of volatile suspended solids. Solids from other waste sources are negligible, ------- 1365 10.85 S-126.3 5.85 10.25 7.40 37.30 6.16 5000 3000 10,000 SCALE IN FEET WATER QUALITY STUDY \ % Volatile Solids in J Sludge Bed Deposits SLUDGE BED DEPOSITS S-130.8 River Mile SNAKE RIVER. LEWISTON. IDAHO US DEPARTMENT OF HEALTH,EDUCATION,6WELFARE PUBLIC HEALTH SERVICE REGION IX PORTLAND,OREGON ------- 46 These bottom samples were analyzed for volatile solids, and the percentage of volatile matter in the respective samples is indicated in Figure 5. Under present flow conditions, the velocities and turbulence of the stream are sufficient to keep most of the settleable solids load in suspension. Only in a few of the deep pools and eddies are the velocities reduced to an extent where deposition occurs. Even in these areas, however, deposition no doubt occurs only during low summer and fall flows. Sludge deposits accumulating during low flow periods are apparently scoured out by high flows during flood stages, a situation that will not prevail when the waters are impounded. There was visual evidence of highly colored industrial wastes in the vicinity of the packing plant and pulp mill outfalls. Since the food-processing plants were not in operation during the survey, no observations were obtained regarding the visual effects from this waste source. Bacterial Quality Bacterial analyses including total coliform, fecal coliform, and fecal streptococci were carried out on a limited number of samples, using the membrane filter method of analyses. The initial results were considerably higher than could be accounted for from existing waste sources. Because of this fact, the State water pollution con- trol agencies of Idaho and Washington and the Public Health Service ------- 47 similar streamflow conditions. It was also agreed that the analyses should be carried out on the ground and under the best possible laboratory controls in order to eliminate all possible sources of error. In order to approach similar streamflow conditions, it was neces- sary to postpone this follow-up work for approximately one year. In July of 1964 a joint bacterial study was conducted by the State water pollution control agencies of Idaho and Washington and the Public Health Service. Eight samples were collected over a period of five days at sampling stations on the Clearwater and Snake Rivers above all waste discharges in the Lewiston-Clarkston area and at three sampling points across the Snake at River Mile 131.5, which is below all points of waste discharge. The following tests were carried out: 1. Coliform density, using the membrane filter technique; 2. Coliform density, using the five-tube, most probable number technique; 3. Confirmation of membrane filter colonies by picking to phenol red lactose broth and transferring all positives to brilliant green lactose bile broth; 4. Double confirmation of MPN positives to E. C. broth and brilliant green lactose bile. The E. C., or elevated temperature test, at 44.5 degrees Centigrade gives the coliform density of fecal origin. Table IX summarizes the bacterial analyses carried out during ------- 48 TABLE IX BACTERIOLOGICAL ANALYSES SUMMARY July 1964 Snake and Clearwater Rivers River Average Coliform Densities Per 100 ml Station Mile MF 5 Tube MPN 5 Tube EC Spalding CLW-11.6 728 1,270 315 Above Asotin S-147.0 130 160 10 North S-131.5 1,378 2,604 280 Middle S-131.5 1,230 3,734 151 South S-131.5 796 1,431 141 The results indicate there is some bacterial contamination of sewage origin entering the Clearwater and Snake Rivers in the Lewiston- Clarkston area. This is much less than was found in the initial sur- vey in 1963. The bacterial levels do not indicate a serious bacterial pollution problem; however, there is a potential threat in the use of ------- DIFFUSION STUDIES A diffusion study was conducted as a part of this survey in order to acquire more definitive information as to the mixing charac- teristics of the Snake River in the Lewiston-Clarkston area under prevailing flow conditions. A fluorescent dye tracer (Rhodaraine B dye) was introduced into the Potlatch Forests, Inc., pulp mill effluent to tag a given mass of industrial waste. The dye was introduced first as a large quantity instantaneously and, second, in small amounts continuously over a period of an hour. A fluorometer with pump was installed in a boat and by traveling across the stream at three different stations from River Mile 139.0 to 135.0, the water was pumped continuously through the instrument which measured the presence of the dye to concentrations as low as 0.1 part per billion. The measured dye concentration was continuously recorded, providing a permanent record of the passage of dye at each station. Although unforeseen operating difficulties presented some prob- lems, the study did show that nearly complete mixing of streamflow and waste loads from the Lewiston-Clarkston area had occurred by the ------- EFFECTS OF IMPOUNDMENT AND RESERVOIR OPERATION ON WATER QUALITY The previous discussions document water quality conditions and the ability of the stream to assimilate municipal and industrial wastes under prevailing streamflow conditions. The following dis- cussions will relate to the effects of impoundments and streamflow regulations for hydroelectric power production upon water quality, water uses, and waste disposal problems of the area. The construction of Lower Granite Dam can be expected to mate- rially alter the characteristics of the Snake and Clearwater Rivers and the rate at which organic matter will be stabilized by the stream self-purification processes. Slack-water conditions of impoundment will result in reduced stream velocities which will favor the deposition of suspended solids and will reduce diffusion and mixing of wastes in the stream, result- ing in reduced stream reaeration. Reduced velocities and increased retention time in the impoundment will cause an increase in surface temperatures which will favor the growth of algae. (The presence of essential nutrients contained in the treated wastes will also encour- age algal production.) This growth would degrade water quality for municipal and industrial use and would be especially objectionable in the Clearwater arm of the impoundment, from which the City of Lewiston ------- 51 The following comments present a brief analysis of some of the probable current patterns, travel times, and reaeration rates that are expected to prevail in the impoundment during the late summer and fall. Effects of Impoundment According to studies by Yih (1958)—^, Debler (1959)—^, Harleman (1961)-^, Duncan et al. (1962)—^, and Burt (1963)—^, a relationship between reservoir morphometry, discharge, density, gradients, and flow pattern can be described by empirical solu- tions of the densiometric Froude number, F^: Q = Turbine discharge. W = Reservoir width at the depth, zQ, and at observation depths. zQ = Depth from surface to centerline of turbine intakes. p = Density of water at zQ. g = Gravity acceleration. jQ = Slope of vertical density gradient at zQ. These studies suggest that, for intermediate depth reservoirs with characteristics similar to those proposed for the Lower Snake River, density currents may develop under summer conditions. These density currents will increase velocities through the affected sections and reduce reaeration at these sections to a negligible ------- 52 Dr. W. V. Burt, Chairman, Department of Oceanography, Oregon State University, has carried out preliminary studies on the tempera- ture characteristics resulting from the construction of Ice Harbor, Lower Monumental, Lower Granite, Asotin, China Gardens, High Mountain Sheep, Hells Canyon, Oxbow, and Brownlee Dams on the Snake River and Dworshak and Penny Cliffs Dams on the Clearwater. Dr. Burt cautioned, however, that the analytical relationships evaluated in his report have not been fully corroborated: "It should be emphasized that more field measurements in actual reservoirs are required before these relationships will be completely understood." On the basis of these preliminary studies, he predicts: 1. Some reduction in temperatures is anticipated in the Lower Snake River after full reservoir development, assuming that low- temperature water is available from upstream; 2. High Mountain Sheep Dam is expected to deliver cooler than normal water to the next downstream impoundment; 3. Dworshak and Penny Cliffs Dams will lower the temperatures of the Clearwater River. From these studies and from personal conferences with Dr. Burt, it is assumed that the probable thickness of the Lower Granite Reser- voir density current will be about 75 percent of the total depth at the dam site, or 105 feet, during August-September. Based on a uniform density current thickness of 105 feet, then, the intersection of the density current and reservoir surface will be near River Mile 120.0. A plot of the probable density current profile is shown in ------- Figure 7 illustrates the probable effects of impoundment on cross-sectional velocities in Lower Granite Reservoir. During periods of low discharge, the increased area will reduce velocities to about ten percent of the natural channel velocities. This rela- tionship is not constant because the reservoir pool elevation will be held relatively constant at elevation 738 feet MSL. Thus, at 200,000 cfs, the impounded velocities will be about 30 percent of the natural channel velocities. Figure 8 shows the increased travel time from about River Mile 140.0 to the Lower Granite Dam at River Mile 107.5 under impoundment conditions compared to natural channel conditions. For an average discharge of 25,000 cfs, total travel times are about 8.5 hours for natural flow conditions and 8.0 days for impoundment conditions, or approximately 23 times longer. As seen from Table IX, the travel times through the proposed reservoir have been adjusted for reduced cross-sectional areas below River Mile 120.0 due to development of ------- DEPTH POOL ELEV.=738 FT. MSL Stagnant 20 40 60 80 100 120 110 115 120 125 130 135 140 RIVER MILE ESTIMATED DENSITY CURRENT PROFILE LOWER GRANITE RESERVOIR August-September Conditions Average Discharge = 25,000 C.F.S. ------- 10.0 5.0 4.0 3.0 co 0.15 10 20 30 200 40 50 100 300 400 DISCHARGE IN 1,000 C.F.S. VELOCITY-DISCHARGE RELATIONSHIPS UNDER NATURAL CHANNEL AND IMPOUNDMENT CONDITIONS Snake River Mile 132.0 Lower Granite Reservoir ------- 240 220 200 NATURAL CHANNEL 140 135 130 125 120 115 110 SNAKE RIVER MILE ESTIMATED TRAVEL TIMES UNDER NATURAL CHANNEL AND IMPOUNDMENT CONDITIONS Through Lower Granite Reservoir Discharge=25.000 C.F.S. August-September Conditions ------- 57 TABLE X ESTIMATED CROSS-SECTION VELOCITIES AND TRAVEL TIMES FOR LOWER GRANITE RESERVOIR WITH AVERAGE DISCHARGE = 25,000 cfs Cross- sectional Average Travel Time River Area (sq. ft.) Velocity (days) Mile Total Effective* (fps) (rai./day) Increment Total 139.0 62,000 62,000 0.445 7.2 0.21 137.5 51,000 51,000 0.42 6.8 0.37 0.21 135.0 71,000 71,000 0.325 5.3 0.94 0.58 130.0 83,000 83,000 0.30 4.9 1.00 1.52 125.0 83,000 83,000 0.25 4.1 1.22 2.52 120.0 125,000 125,000 0.185 3.0 1.67 3.74 115.0 167,000 145,000 0.185 3.0 1.67 5.41 110.0 167,000 128,000 0.175 2.9 0.86 7.08 107.5 218,000 164,000 7.94 ^Density current cross-sectional area. The self-purification capacity of the Lower Snake River will be greatly reduced due to increased depths and decreased velocities. The reaeration rates (K^ ) for Lower Granite Reservoir have been e worked out at an average discharge of 25,000 cfs, using relationships developed by Churchilli^ and O'Connor and Dobbins^. These relation- ships express the reaeration rate of a river as an exponential function ------- Churchill: K = H.6 y°-969 2e " H1.673 58 O'Connor Isotropic: K2 = e h / V = Velocity, fps. H = Depth, feet. From Table X, it is seen that the reaeration rates for Lower Granite Reservoir will be very small in the reach above River Mile 120.0 (Ko = 0.01, more or less). Below River Mile 120.0, e the development of a density current will limit reaeration to whatever oxygen can be exchanged across the stagnant water-density current interface. Assuming laminar flow, then, reaeration below River Mile 120.0 will be essentially zero in the density current. On the basis of the above calculations and with existing back- ground levels of BOD entering the Lower Granite pool, the dissolved oxygen concentration at the lower end of the pool, during the crit- ------- 59 TABLE XI ESTIMATED REAERATION RATES (K2 ) FOR LOWER GRANITE RESERVOIR e AUGUST-SEPTEMBER CONDITIONS WITH AVERAGE DISCHARGE = 25,000 cfs Average Average K2 River Depth Velocity Reaeration Rate ( e) Mile (feet) (fps)* 01 Connor Churchill Average 139.0 44 0.40 0.027 0.009 0.018 137.5 53 0.49 0.022 0.008 0.015 135.0 71 0.35 0.012 0.003 0.008 130.0 77 0.30 0.010 0.003 0.006 125.0 95 0.30 0.007 0.002 0.004 120.0 98 0.20 0.006 0.002 0.004 115.0 95 0.17 a/ a/ a/ 110.0 100 0.20 a/ a/ a/ 107.5 105 0.15 a/ a/ a/ *Average density current cross-section velocity. ------- 60 Effects of Power Operations The streamflow characteristics that will prevail in Lower Granite pool as a result of hydroelectric power operations have not been fully determined. These will change as upstream develop- ments are completed and as the complex Northwest power system is operated to meet the changing power demands. It is reasonable to assume that hydroelectric facilities will eventually be used pri- marily for power-peaking purposes, thereby producing highly vari- able flows during a 24-hour period. It has been reported that power-peaking operations of Dworshak Dam will bring flows up to about 10,000 to 15,000 cfs in the Clearwater River during the period of normally low flows. Flows below the Asotin Dam on the Snake River may be expected to reach 90,000 cfs during similar periods. The minimum flows resulting from storage during off-peak operations may be as low as 1,000 cfs. The flow passing through the pool in any day will approximate the average daily flow of the two streams. These extremes in flow, together with the frequency and duration of such flows, are of major significance from the standpoint of evaluating the effects of waste discharges from the Lewiston-Clarkston area on water quality conditions in the Lower Granite pool. The minimum flows during low power demand periods, approximat- ing 1,000 cfs for a period of several hours, will tend to permit the residual wastes to accumulate in a concentrated form around the ------- 61 and little opportunity for mixing. It is anticipated that the higher flows which will accompany power-peaking operations will tend to provide some longitudinal mixing of such pockets of wastes; however, this cannot be predicted with any degree of accuracy. For this reason, it may be necessary to maintain minimum flows in excess of those now contemplated. There have been instances where such accumulations of waste have moved downstream in a more or less un- diluted slug. If this condition should prevail in the Lower Granite pool, it could be possible for the dissolved oxygen to be completely depleted in these pockets of pollution. There is also the possibility of reservoir stratification with low dissolved oxygen concentrations in the deeper waters. If this condition should prevail in Asotin reservoir with releases from these depths only, there will be no opportunity for reaeration in Lower Granite pool. Such a situation would have a very serious effect on the waste assimilative capacity of the pool. Unless future upstream power installations are planned to provide for the necessary flexibility in operation to offset these potential damages to water quality, they can seriously interfere with practically all other anticipated water uses. Fortunately, it will be possible to study some of these factors, especially waste diffusion and stream- flow patterns in the Lower Granite pool at various flow rates under natural streamflow conditions before the Asotin Dam is constructed. Such studies should serve as a valuable guide in the design and ------- 62 The power-peaking operations of Lower Granite, Asotin, Dworshak, and proposed Penny Cliffs Dam may create hydraulic conditions where discharges from Asotin Dam may cause a backflow into the Clearwater arm of the impoundment. As previously stated, the intake for the Lewiston surface water supply is located at River Mile 2.6 in the Clearwater arm of the impoundment, and reversal of flow in this channel could carry Snake River water up to the intake. Under these conditions, it would be possible also for the backflow to carry the waste discharges from the Potlatch Forests, Inc., and those from the City of Lewiston upstream to the city water intake. For these rea- sons and because of the likelihood of objectionable algae growths in the impoundment which could create serious taste and odor prob- lems in the public water supply, the intake for the Lewiston city water supply should be relocated at a point above the existing Washington Water Power Company dam. Furthermore, since the Clearwater arm will undoubtedly be used extensively for recreational purposes, it would be desirable for all waste discharged to be located far enough below the confluence of the Clearwater and Snake Rivers to prevent highly colored pulp mill wastes and municipal sewage treatment plant wastes from being car- ried into this area. As previously stated, settleable solids will settle to the bottom of the impoundment. It is unlikely that the higher flows during power- peaking operations will re-suspend this material and move it out of ------- organic matter on the bottom of the reservoir with its attendant detrimental effects on all water uses, it is imperative that the highest possible degree of settleable solids removal be provided ------- FUTURE WATER USES With the advent of a slack-water pool at the doorstep of a heavily populated area, it is a certainty that water-oriented recreation will expand very rapidly. Water-contact sports such as swimming, water skiing, and so forth, demand a high quality water, both from an aesthetic and a bacteriological standpoint. It is likely that these activities may take place throughout the pool, including the immediate vicinity of waste outfalls. For this reason, the maximum possible diffusion of such wastes should be planned for. It will also be imperative that very effective and efficient disinfection of sewage and animal waste treatment plant effluents be accomplished. As noted previously, the present bacterial quality of the Snake River downstream from the waste outfalls in the area does not meet recommended bathing water standards even though chlorina- tion of all sewage treatment plant effluents is practiced. The reliability of bacterial control by chlorination of primary sewage treatment plant effluents is subject to considerable variation. This is due largely to the rapidly changing flows and organic con- tent of such effluents, making it extremely difficult to adjust the chlorine dosage to meet the variable chlorine demand of the wastes. For this reason, where continuous and effective disinfec- tion of sewage effluents is required, it is usually considered ------- 65 chlorination more effective and more reliable. This added factor of safety is especially important in this situation where high quality water uses are located so near to sources of pollution. For this reason the water pollution control agencies of the two states believe that secondary treatment followed by disinfection will undoubtedly be required to adequately protect all essential water uses. The Public Health Service concurs in this evaluation. There is also a possibility that the color and foam from the pulp mill wastes may create undesirable aesthetic conditions, if the point of discharge is in close proximity to recreational areas. This can be minimized to some extent by accomplishing the maximum diffusion and dilution of wastes within the reservoir. There is a possibility that hydraulic model studies would provide information concerning the effectiveness of outfall dif- fusers and the degree to which longitudinal mixing may be accom- plished under the high streamflow conditions resulting from power - peaking operations. With the economic development of the area, domestic and indus- trial waste production will increase during future years. It appears reasonable that pulp production may be expected to expand from 700 to 1,000 tons per day. Comparable increases in raw wastes may be expected from other waste sources. Therefore, it is assumed that within the next fifty years the raw waste loads from this area may ------- 66 waste loads reaching the stream since improved waste treatment practices should result in greater removals than is the case at this time. It may be reasonably expected, however, that the amount of organic matter reaching the stream as residual wastes from waste treatment facilities may have a population equivalent of from 600,000 to 700,000. This load would have the effect of exerting slightly less than one milligram per liter demand on the dissolved oxygen resources of the stream at an average daily flow of 25,000 cfs. Under existing streamflow conditions, with the accompanying high reaeration rate, the oxygen resources will be quickly restored. However, with the impoundment, this demand will be felt in the lower portions of the pool and will act to further depress dissolved ------- BIBLIOGRAPHY 1. C. H. Yih, "On the Flow of a Stratified Fluid." Proceedings, 3rd National Congress of Applied Mechanics, pp. 857-861. 1958. 2. Walter R. Debler, "Stratified Flow into a Line Sink." Journal of the Engineering Mechanics Division, Proceedings of the American Society of Civil Engineers, vol. 2093, pp. 51-66. July 1959. 3. Donald R. F. Harleman, "Testimony Before the Federal Powpr Commission, Projects 2243 and 2273." Vol. 75, pp. 14,022-14,043. Washington, D. C., July 20, 1961. 4. Walter Duncan, Donald R. F. Harleman, and Rex Elder, "Internal Density Currents Created by Withdrawal from a Stratified Reservoir." Division of Water Control Planning, Tennessee Valley Authority, and Walla Walla District, U. S. Army Engineers, Norris, Tennessee, February 1962. 19 pp. 5. Wayne V. Burt, "Preliminary Study on the Predicted Water Changes of the Lower Snake River due to the Effects of Projected Dams and Reservoirs--Part I: Forecasting Water Temperature Changes Due to Flow through Intermediate Depth Reservoirs." Corvallis, Oregon, November 1963. 27 pp. 6. M. A. Churchill, "The Prediction of Stream Reaeration Rates." Journal of Sanitary Engineering Division, American Society of Civil Engineers, July 1962, pp. 1-46. 7. D. J. O'Connor and W. E. Dobbins, "The Mechanics of Reaeration in Natural Streams." Transactions. ASCE, vol. 123, pp. 641-684. ------- PAGE NOT AVAILABLE ------- APPENDIX PRESENT AND POST-IMPOUNDMENT WATER QUALITY CONDITIONS SNAKE AND CLEARWATER RIVERS LEWISTON, IDAHO-CLARKSTON, WASHINGTON AREA The tables appearing in the Appendix are a record of all analyses carried out during this study, except the bacteriological analyses The 1963 bacteriological data are not reported because of unaccounted-for discrepancies. However, data collected during the joint State-PHS study in July 1964 are reported and are considered ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- PAGE NOT AVAILABLE ------- |