Snake River Water Quality:
A Discussion of Current Practices and Problems
Submitted as Partial Fulfillment of the Requirements of
NNEMS Grant No. U-913061-01-0
Zimri Hoore
November 27, 1989
-------
50272-101
REPORT DOCUMENTATION
PAGE
1.REPORT NO.
3. Recipient s Accession
4. Title and Subtitle
Snake River Water Quality: A Discussion of Current Practices and Problems
5. Report Date
Completed Fall 1989
)f(S)
I Zimri Moore
8. Performing Organization Rapt No.
9. Performing Organization Name and Address
University of Idaho
Department of Civil Engineering
Moscow, ID 83843
10. Project/Taskwork Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
Office of Cooperative Environmental Management
499 South Capital Street, SW A-101-F6
Washington, DC 20460
13. Type of Report & Period Covered
Technical Report
14.
15. Supplementary Notes
16. Abstract (Limit: 200 words)
2517 - Snake River Water Quality: A Discussion of Current Practices and Problems
This report is part of the National Network for Environmental Management Studies under
the auspices of the Office of Cooperative Environmental Management of the U.S. Environmental
Protection Agency. Water quality impacts of a single hydroelectric impoundment are relatively
simple to predict however, consideration of cumulative impacts to fisheries, wildlife, and water
iity resulting from combinations of additional impoundments must also be considered. By
_ .structing a water quality model, the Snake River Risk Assessment team intends to provide the
means to fully assess the environmental risks associated with potential individual or multiple
hydroelectric developments on the river.
Construction of the water quality model remains in the preliminary stages of information
gathering and familiarization with water quality concerns in th study area. To facilitate this
stage of model development, a data base of pertinent literature and water quality was reviewed
and compiled. The following report has been prepared based on the review of the literature
contained in the data base. It is intended to familiarize members of the Snake River Risk Assess-
ment team and interested residents of the study area of existing conditions, water use practices,
wastev/ater disposal methods, and environmental factors that contribute to existing water quality
conditions in the Snake River.
17. Docuement Analysis a Docuement Dlscrlptore
b. Idenlifiofs/Open-Endod Terms
c. COSATI Field/Group
I^^Ava
lyallablility Statement
19. Security Class (This Report)
20. Security Class (This Page)
21. No. of Pages
22. Price
(See ANSI-Z39.18)
OPTIMAL FORM 272 (4-77)
(Formerly NTIS-35)
Department of Commerce
-------
DISCLAIMER .._
This report was furnished to the U.S. Environmental Protection
Agency by the graduate student identified on the cover page, under
a National Network for Environmental Management Studies
fellowship.
The contents are essentially as received from the author. The
opinions, findings, and conclusions expressed are those of the author
and not necessarily those of the U.S. Environmental Protection
Agency. Mention, if any, of company, process, or product names is
not to be considered as an endorsement by the U.S. Environmental
Protection Agency.
-------
Executive Summary
The impetus for development of a water quality model of the
Snake River between American Falls Reservoir and Swan Falls Dam
stems from numerous applications for Federal Energy Regulatory
Commission permits for new hydroelectric impoundments in this
portion of the river. Water quality impacts of a single
impoundment are relatively simple to predict however, consideration
of cumulative impacts to fisheries, wildlife, and water quality
resulting from combinations of additional impoundments must also
be considered. By constructing a water quality model, the Snake
River Risk Assessment team intends to provide the means to fully
assess the environmental risks associated with potential individual
or multiple hydroelectric developments on the river.
Cconstruction of the water quality model remains in the
preliminary stages of information gathering and familiarization
with water quality concerns in the study area. To facilitate this
stage of model development, a data base of pertinent literature and
water quality was reviewed and compiled. The following report has
been prepared based on the review of the literature contained in
the data base. It is intended to familiarize members of the Snake
River Risk Assessment team and interested residents of the study
area of existing conditions, water use practices, wastewater
disposal methods, and environmental factors that contribute to
existing water quality conditions in the Snake River.
-------
Objectives of this Paper
1. To inform residents of the study area and members of the study
team modeling Snake River Water Quality of existing water use
and waste disposal practices that degrade water quality in the
study area and to describe the problems associated with these
practices.
2. To recognize losses and or gains to different interest groups
that would be associated with any change in water use and
waste disposal practices.
3. To describe the types of impacts that might be associated with
further agricultural and hydroelectric development in the
study area.
-------
Introduction
Rivers are in a constant state of change, continually seeking
a new equilibrium condition. As the river bed and banks attempt
to adjust to varying flow rates and sediment loads, aquatic life
in the riverine environment must adjust species diversity and
population to compensate for changes in their environment.
Alterations as small as a few degree difference in temperature may
shift the algae community of a water body toward the dominance of
an entirely different species. Damming the river, increasing or
decreasing sediment loads, increasing nutrient loadings, and other
changes have a substantially larger impact on the river
environment. The water quality characteristics and the river's
physical boundaries attempt to reach a new equilibrium state in
response to changes in the river system. Biological components of
a riverine system also respond to these changes in their
environment, shifting populations and species to reach a new
equilibrium.
Prior to settlement of the region by men of european descent
the Snake River was free flowing, virtually void of toxins, and
radioactivity was at natural background levels. Abundant
populations of salmonids inhabited the relatively cool clean waters
of the study area and aquatic plant and algae populations along the
river were less abundant. However, in contrast to pristine
conditions in most other water bodies, the Snake River's
-------
productivity was naturally high before significant anthropogenic
influences (Parametrix, 1979).
Permanent settlement of the region has greatly increased the
nutrient load to the river system. Before Public Law 92-500 was
implemented the river served as a convenient means of disposal for
various wastewaters. In particular, excess organic matter and
inorganic nutrients from untreated wastewaters, fertilizers in
agriculturally applied irrigation return water, and runoff from
feedlots stimulated the river's productivity resulting in a highly
eutrophic system. Oxygen depletions by respiring photosynthetic
plant populations alone were severe enough to cause fish kills in
American Falls Reservoir. Organic sludge deposits and foul odors
from decaying aquatic growths were common throughout the river
basin (Federal Water Pollution Control Administration (FWPCA),
1968). Today most or all point source pollutant discharges to the
river receive some degree of treatment before disposal. Despite
construction of wastewater treatment facilities and other efforts
to clean up the river a significant pollution problem in the form
of excess nutrient loading or eutrophication is still present.
Monitoring and regulation of point source polluters by the U.
S. Environmental Protection Agency (USEPA) has reduced the
pollutant load in the river. Improvements in water quality
resulting from USEPA actions are manifest in the relative absence
of fish kills resulting from oxygen depletion by respiring
-------
phytoplankton and Biochemical Oxygen Demand (BOD) (pers. comm. W.
Poole, 1989). The degree to which eutrophication has been slowed
or reversed by these efforts is difficult to quantify since the
trophic state of a body of water is largely a subjective or
qualitative parameter. Some improvement in the trophic state has
occurred as a result of decreased nutrient loads irrespective of
a measure of improvement.
Though current nutrient loadings are partially attributable
to point sources, treatment of point sources prior to discharge
substantially reduces current point source nutrient contributions
to the river. As a result the extremely high level of productivity
in the Snake River is primarily a result of non- point sources
(Idaho Department of Health and Welfare Division of Environmental
Quality (IDHW-DEQ), 1989a and 1989b).
Impoundments and flow modifications create additional water
quality problems. The combination of a heavy nutrient load and an
optimal environment for growth of plankton and aquatic macrophytes
in warm, slow moving, impounded water exacerbates problems
associated with a high nutrient loading. Aquatic populations are
subsequently altered in favor of warm water animal species and
provide a more favorable environment for plankton and aquatic
macrophytes. Eutrophic conditions are particularly conspicuous
during the growing season in the Twin Falls and Thousand Springs
-------
reaches of the Snake River, the area on which this report
concentrates.
Physical Description of the Study Area
The study region is defined as the river itself and the areas
immediately adjacent to it between American Falls Reservoir and
Swan Falls Dam. Its climate is arid to semi- arid with an
approximate annual rainfall of 10-15 inches and abundant sunlight.
Summers are warm with high temperatures commonly above 90 degrees
and cool winter temperatures occasionally dropping below zero.
Because water is relatively scarce in the region, the river is
repeatedly exploited for various uses as it flows across the desert
Snake River Plain. Below this plain lies the largest and most
productive aquifer in the Northwest which supplies most local
municipal water systems (FWPCA, 1968).
Nearly the entire population of the region lives within a few
miles of the river. Exceptions to this rule generally do not occur
unless irrigation water is supplied to areas more distant from the
river by canal or groundwater pumping. Twin Falls and the Rupert-
Burley area are the two major service areas within the study
boundaries. The Pocatello and Idaho Falls service areas are
upstream of the study area boundary. Because the heaviest water
use occurs in the Twin Falls area the most significant impacts are
generally found in this area (pers. comm. W. Poole and M.
McMasters, 1989).
-------
HENRYS LAKE
f* Jt A * ^*\
COLUMBIA RIVER BASIN
RIVER MILE INDEX
SNAKE RIVER
Part IT Snake River above Weiser
D-NEVADA-
WYOMING
CASCADE 'DAM
BULLY CREEK
"C-^V
AGENCY
VALLEY DA
(BOISE DIVERSION
'vARROWROCK
2 . / n*f\ u
•^-».
LUCKY PEAK \
Vr\
1
-------
Economic forces play a major role in producing the water
quality conditions in the river since utilization of water
resources is the primary basis for the local economy.
Approximately 80 percent of the nations aguaculture production of
trout is found in the study area between Twin Falls and Hagerman
(pers. comm. C. M. Falter). Waste from hatchery production
receives some treatment in many of the larger hatchery facilities
but most of the smaller trout producers provide limited or no
treatment of wastes before they are discharged to the river.
Irrigated agriculture is the largest water user in the region
and consequently has the largest impact on water quality. The
magnitude of agricultural diversions is demonstrated by the
presence of a water right that enables diversion of the entire
Snake River for irrigation at Milner Dam (pers. comm. M. McMasters,
1989). Feedlots and Dairies produce a tremendous amount of organic
nutrients from cattle waste that is often washed directly into the
Snake River via irrigation return drains and small streams.
Numerous food processing plants are found in the region to process
the abundant agricultural production made possible by irrigation.
Treated wastewater from these plants is also discharged to the
river.
Although the numerous hydroelectric facilities in this portion
of the river do not contribute to the pollutant load, the
impoundment of water and other hydrologic modifications to stream
-------
flow compounds many of the water quality problems in the river.
The previously mentioned activities are almost exclusively
responsible for sustaining the economic activity of the region,
and in so doing they simultaneously create some of the most serious
pollution problems in the basin. Growth of these industries is
limited to a large extent by the cost and availability of water
resources in the area. Because the region's economy is so heavily
dominated by agriculture, expansion of the economy is directly
linked to agricultural expansion which is controlled by the
availability of water. Population is similarly tied to water
resources since the population cannot substantially expand without
a sufficient economic base. It is therefore very likely that the
area's populace and economy will continue to grow at a relatively
slow rate.
Water Quality Control Progress
Since 1969 several programs and improvements have been
implemented to improve water quality in the Snake River Basin.
Most notable have been the regulation of waste handling at cattle
feedlots and wastewater disposal for point source discharges.
Other programs such as the Rural Clean Water Program attempt to
improve water quality, largely by controlling sediment loads in
agricultural irrigation runoff.
-------
Limited improvements in water quality have been realized by
these programs. Turbidity and sediment loads have been reduced in
the Rock Creek watershed through the Rural Clean Water Program and
fish kills in the mainstem Snake River appear to have been
eliminated within the study area (Idaho Department of Health and
Welfare, Division of Environmental Quality, Water Quality Bureau
(IDHW-DEQ-WQB), 1989 and pers. comm. W. Poole, 1989). Though
improvements have been made, their cost effectiveness has been
questioned. Abundant aquatic growths are still present, salmonid
populations have not substantially rebounded, sediment loads remain
high, and water quality improvements in tributaries such as Rock
Creek are quickly lost when the creek reaches the Snake River.
Limited returns on past water quality protection expenditures cause
many to question whether benefits could be realized from further
expenditures (T. Klahr, 1989).
8
-------
Pollutant Sources
Fish Hatcheries
Between Twin Falls and Hagerman lies the Thousand Springs area
where the Snake River Plain Aquifer discharges to the river. With
the exception of elevated nitrate (NO3) levels, these springs yield
water with negligible pollutants at a nearly constant temperature,
ideal conditions for fish farming. The abundance of this high
quality water has enabled Idaho to lead the nation in aquaculture
production of trout. Of the approximately 6000 to 7000 cfs that
flows from springs in the area, it is estimated that 80 to 90
percent or more of this flow is utilized for trout production.
Billingsley Creek is a prime example of the intensity of spring
flow utilization for fish farming. In the seven miles from its
spring source to the Snake River, Billingsley Creek flows are
utilized by 14 different fish hatcheries (pers. comm. M.
McMasters).
The total contribution of waste from hatcheries is difficult
to quantify because of the range of size and practices used in
producing the fish. Many of the larger producers collect and treat
fish wastes from raceways, diminishing the pollutant load to the
river. Most smaller producers raise the fish in gravel or dirt
lined ditches. Facilities of this type generally preclude removal
and treatment of wastes before discharge to the river because of
difficulties in removing wastes from raceways with erodible
9
-------
bottoms. Economic factors associated with providing cleaning and
treatment capabilities at small facilities with relatively few fish
also discourage pollutant removal. As a result most fish wastes
from smaller fish farms and hatcheries reach the river undiluted.
Other growers raise fish in irrigation drainage water so the
contribution from fish wastes and the contribution from agriculture
wastes become more difficult to distinguish.
For these reasons the concentration and quantity of wastes
discharged to the river from a given hatchery is widely varied.
Further variation is introduced by the range of sizes of fish farms
and hatcheries and by the species of fish produced.
Pollutants generated at fish farms and hatcheries are
principally of an organic nature. Most significant is the urea
and solid waste products excreted by the fish. In addition to
substantial contributions of organic nitrogen, the Twin Falls
office of IDHW-DEQ is concerned that fish feeds and subsequently
fish wastes from the hatcheries are higher in phosphorus than is
necessary to meet the nutrient requirements of the fish. Resulting
excess effluent phosphorus is suspected of stimulating aquatic
growths in the mainstern Snake River (pers. comm. M. McMasters
1989). Trophic responses of the river to hatchery effluent are
probably greater than for similar volumes of other wastewaters due
to the large percentage of phosphorus found in the orthophosphate
form. An estimated half of the total phosphorus entering
10
-------
hatcheries as fish feed leaves the raceways in the orthophosphate
form (E. Brannen, 1989).
Other pollutants associated with hatchery effluents are
primarily the BOD and suspended solid load discharged in effluent
from the raceways. Suspended solids may be particularly high in
earth lined raceways where the vigorous swimming action of fish
entrains and suspends organic and inorganic sediments. Effluent
limitations for hatcheries and fish farms have been developed for
USEPA but do not appear to have been implemented by federal
agencies. IDHW-DEQ currently regulates hatchery effluents,
principally on the basis of suspended solids and BOD loadings.
Dairies and Feedlots
Animal wastes are generally accepted as significant
contributors of nutrients to most watersheds in which they are
found (Holt, Timmons, and Latterell, 1970; Holt, 1971; Robbins,
Howells, and Kriz, 1971 in USEPA, 1976). Particularly heavy
loading occurs when cattle are provided free access to a stream
that flows through a feedlot or stockyard as a water source.
Sediment and cattle waste products are washed into streams during
runoff events. Cattle drinking from a stream may defecate directly
in the stream or carry nutrients and wastes directly into the
stream on their hooves and legs as they drink.
11
-------
The problem is more pronounced when the animals are confined
rather than allowed to range over a large area. Wastes from the
higher density feedlots and stockyards are more concentrated and
therefore generally have a greater impact on the receiving stream.
This effect is largely diminished in the Snake River because of the
relatively large volume of water available for dilution compared
to its tributaries. Other wastewaters are generated by wash water
from dairy operations and any other periodic cleaning of animals
or facilities.
Within the study area, the Snake river flows through or
adjacent to portions of Power, Elaine, Cassia, Minidoka, Jerome,
Gooding, Twin Falls, Elmore, and Owyhee Counties. Cattle
populations in these nine counties totaled 562,000 head in 1988
and increased to 596,000 head as of January 1, 1989 (Idaho
Department of Agriculture, 1989). Most of this cattle population
is located within 10 to 20 miles of the river or one of its
tributaries and are found in high densities.
Actual contributions of nutrients to the Snake River depend
on the proximity of the cattle to the river or its tributaries and
the effectiveness of on site measures designed to prevent
contamination of streams and agricultural drains by animal wastes.
Assuming values of 38.8 pounds of total phosphorus and 126.7 pounds
of total nitrogen per year per animal are produced in cattle
wastes, these cattle populations will produce 75.5 million pounds
12
-------
of total nitrogen and 23.1 million pounds of total phosphorus in
1989 (USEPA, 1976).
Although the close proximity of cattle populations to the
river and its tributaries tends to favor a high percentage of
wastes reaching the river, several other factors attenuate the
transport of wastes. Plant cover both retards the flow of cattle
waste products to streams and consumes them as a fertilizer.
Though probably much smaller in magnitude than nutrient
contributions via surface water, nutrient contributions to
groundwater via deep percolation also reduce the direct flow of
nutrients to receiving streams.
In addition to nutrient contributions, the BOD, ammonia,
bacteria, and pathogens contained in cattle wastes are also
significant water quality concerns. Cattle produce much greater
volumes of waste with a higher BOD, approximately 6.4 times the
equivalent BOD of human waste. Assuming this ratio to be true a
stockyard containing 2000 head of cattle would be roughly
equivalent to a city of 13,000 people discharging untreated sewage,
with respect to the BOD (FWPCA, 1968).
Fecal matter from cattle contains pathogens that also afflict
humans. Most pathogens die off relatively quickly when exposed to
an environment other than their original host. However, high
densities of cattle tend to accumulate mud and fecal matter as much
13
-------
as several feet deep. In the warm moist environment provided
within accumulations of mud and manure, pathogens die off slowly
and may even multiply. Thus, when a runoff event occurs or wastes
are illegally discharged to streams, large numbers of pathogens in
high concentrations are introduced into the stream. Summer stream
temperatures are warm and provide a favorable environment for
pathogens and other coliform bacteria. Attrition rates are slowed
and bacteria counts may increase further in the river under these
conditions. Resulting coliform bacteria counts in the Snake River
are very high and recreational uses have been impaired as a result.
(FWPCA, 1968).
The USEPA has established regulations for waste disposal
practices at stockyards and feedlots. Essentially these
regulations prohibit the discharge of animal wastes to streams and
water bodies except during particularly large runoff events.
Accidental or illegal discharges of these wastes persist even with
these regulations (pers. comm. M. McMasters, 1989).
Irrigated Agriculture
Non-point agricultural sources contribute the largest
pollutant load in the Upper and Middle Snake River Basin (Tetra
Tech, 1976 and IDHW-DEQ, 1989a and 1989b). Irrigation tail-waters
carry pesticides, nutrient rich fertilizers, and heavy sediment
loads to the river. To date little concern has been placed on the
pesticide loading of receiving streams. The mainstem of the Snake
14
-------
River in particular has been neglected with respect to monitoring
for pesticides. Limited data is available in the USEPA's STORET
database system and from monitoring programs such as the Rock Creek
Rural Clean Water Program (RCWP), but is generally sporadic and
available at only few sites. Still less documentation appears to
be available on the impacts of pesticide loading on aquatic life
in the river.
Sediment loading to the mainstem of the river also appears to
have received little attention, though more than pesticide
loadings. Soil erosion control programs have been instituted by
the Soil Conservation Service and other agencies in many of the
Snake River's tributaries. A wealth of information on soil loss,
erosion control, and the effectiveness of Best Management Practices
(BMPs) has been collected as part of the Rock Creek RCWP. Limited
information on sediment loads and turbidity in the Snake River can
be found in USEPA's STORET data base.
Runoff from individual fields, especially those irrigated by
furrow irrigation, carry sediment into drainage canals which
eventually drain into the river. Most of the smaller canals that
flow over the precipitous canyon wall percolate through talus
debris piles formed from rock spalling off canyon walls. As it
percolates through this debris pile it drops much of its sediment
load. Accumulated sediment and rock debris tend to remove many of
the other pollutants associated with irrigation wastewaters in a
15
-------
fashion similar to wastewater treatment by land treatment systems.
Irrigation drainage entering the river without the benefit of this
pollutant removal system has higher sediment loads, higher nutrient
concentrations, and higher pesticide concentrations. The
effectiveness of the talus slopes is evidenced by comparison of
typical irrigation drainage with the Perrine Coulee hydroelectric
facility's discharge to the Snake River. Irrigation tail-waters
on the canyon wall are conveyed through a penstock to a
hydroelectric turbine, bypassing the talus slope and discharging
the wastewater directly to the river, creating the sediment laden
pollutant plume in the river.
Many of the cultural practices used in crop production
contribute to the sediment load. Low till methods of crop culture
have been found to be one of the best methods of controlling
erosion and soil loss (pers. comm. M. McMasters and IDHW-DEQ-WQB,
1989) . Though some farmers have incorporated low till and other
Best Management Practices (BMPs) as part of their cultural
practices, implementation of BMPs is not ubiquitous in the region.
Soil losses by irrigation runoff are often manifest by severe soil
losses from lands operated with little regard to soil erosion and
accumulations of soil on lands operated by erosion-conscious
farmers (D. Carter, 1976).
Nutrient contributions from irrigation return flows are also
substantial. Nutritive requirements for terrestrial plant life
16
-------
are practically identical to those for aquatic plant life with
respect to substance or compound. Thus nutrients from decayed
terrestrial plant matter and fertilizer applications carried in
irrigation return flows stimulate the production of aquatic plant
life in the Snake River. Generally the principal nutrients of
concern in an aquatic system are nitrogen and phosphorus. Though
nitrogen requirements are much larger, it is usually available in
abundant quantities, while phosphorus is relatively scarce and
usually limits the productivity of aquatic systems. Both of these
nutrients are found in agriculturally applied fertilizers.
Research on agricultural return flows in the study area
indicate that phosphorus is removed from irrigation water by
applying it to crop lands (approximately a 70 % reduction in P04-
P). Thus, with respect to phosphorous, the application of Snake
River water irrigated lands has a beneficial impact on water
quality (D. Carter, J. Bondurant, and C. Robbins, 1970 and D.
Carter, M. Brown, C. Robbins, and J. Bondurant, 1974).
Significant losses of nitrogen occur to both deep percolation
and surface runoff. The most extreme contributions of nutrient
loss to groundwater and receiving streams occurs when fertilizers
are applied directly to irrigation water for subsequent application
to crops. Studies of irrigation plots in the Boise Valley showed
a net loss of nitrogen to irrigated crop land but influent and
effluent nitrogen concentrations from the tract were essentially
17
-------
the same. These results combined with high nitrate levels in
groundwater underlying the study area suggest that greater
efficiencies in water application would also yield greater
efficiency in fertilizer applications (D. Naylor and J. Busch,
1973). Elevated nitrate levels in the study region are generally
thought to be caused by similar mechanisms (pers. comm. M.
McMasters, 1989).
Other Pollutant Sources
Three other pollutant sources are worthy of mention, either
out of public concern or to explain the interaction of pollutants
that enter the Snake River outside the study area. The most
obvious of these is the pollutant contribution from the numerous
municipal and industrial point sources that discharge to the river.
Most point source discharges in the region are domestic or food
processing wastes and are relatively void of toxic materials,
although a wide range of constituents may be present. Major
exceptions are the phosphate processing plants upstream of the
study area which discharge wastewaters with a low organic
component. Before USEPA implemented effluent standards, these
wastes were discharged to the river untreated. At times the BOD
and nutrient contribution from point sources was a serious problem.
Today they constitute a small portion of the total waste load
relative to non-point sources (IDHW-DEQ, 1989a and 1989b). Typical
secondary effluents have total phosphorus concentrations of 3 to
11 mg/1, 15 to 60 mg/1 total nitrogen, and 30 mg/1 or less
18
-------
suspended solids and BOD (Benefield and Randal, 1980 and Metcalf
and Eddy Inc., 1979). The favorable economics and number of
opportunities available for controlling non-point source
contributions compared to the diminishing returns associated with
advanced treatment of point source discharges strongly favors non-
point source controls. As a result, implementation of non-point
source controls has been given a higher priority than additional
point source controls. Pollutant contributions from municipal and
industrial sources are probably not negligible, but are not
discussed further in this paper because of their lack of ability
to effect significant water quality improvements.
Radionuclide contamination of the Snake River may be possible
by transmission of radioactive material via the Snake River Plain
Aquifer from disposal sites at the Idaho National Engineering
Laboratory (INEL). Results of limited monitoring of the Snake
River for radionuclides is available in USEPA's STORET data base.
The U. S. Geological also has information available in open file
reports of groundwater sampling in the vicinity of the INEL.
It is highly unlikely that any radionuclide contamination from
the INEL would have reached the Snake River since the estimated
travel time through the aquifer to discharge points along the river
is in excess of 100 years. The INEL itself has only been in
existence approximately half as many years (U. S. Department of the
19
-------
Interior, Federal Water Quality Administration, Northwest Region,
1970).
Radionuclides could theoretically reach the river via surface
drainage of groundwater irrigated sites closer to the INEL.
Transport of radionuclides to the river in this manner is unlikely
because of the numerous hydraulic connections that must be present.
If such contamination were occurring, the severity would likely be
very small.
In 1970 the Northwest Region of the Federal Water Quality
Administration recommended the removal of existing buried wastes
and the elimination of disposal wells discharging to the aquifer.
At that time evidence had yet to be presented substantiating any
movement of pollutants beyond the INEL boundary after approximately
20 years of operation. Since then action has been taken to monitor
and prevent any further degradation of the aquifer or potential
spread of the radioactive plume (U. S. Department of the Interior,
Federal Water Quality Administration, 1970).
The last pollutant sources of importance in the study area are
the phosphorus mines and phosphorus rich rock formations in
Southeastern Idaho. Waters from the Portneuf River, Henry's Fork,
Blackfoot River and other tributaries accumulate heavy phosphorus
loads as they travel through the phosphorus rich geologic
formations of their watersheds. Before anthropogenic sources of
20
-------
phosphorus entered the Snake River the naturally high phosphorus
concentrations in these streams was probably responsible for the
historically high productivity of the river. Today phosphorus
mining operations and phosphorous ore treatment plants have
increased the phosphorus load to American Falls Reservoir and
downstream reaches of the Snake River above natural levels.
Phosphorus loading in American Falls Reservoir is large enough to
cause the reservoir's productivity to be nitrogen limited at times
(pers. comm. C. M. Falter, 1989). Phosphorus contributions from
this area are one of the most significant factors responsible for
producing the characteristic high productivity, algae blooms, and
aquatic growths found in the Snake River.
21
-------
River Impoundment and Water Management
Water quality impacts in the Snake River are not solely
attributable to the abundance of nutrients and other pollutants.
Water impoundments and river water management practices greatly
influence the physical characteristics of the river. Disruption
of the river's natural flow regime and seasonal cycles of flow rate
and water temperature subsequently alter perennial and seasonal
communities of plant and animal life in the river.
River Impoundments
Impoundments along the Snake River differ from most other
impoundments and reservoirs in that they are nearly all single
purpose projects. Though some secondary benefits may be associated
with a project, they are generally subordinate and of little
concern compared to the primary purpose of the impoundment.
American Falls Reservoir serves as the primary water storage
facility in the study area with a storage capacity of 1.7 million
acre feet. C. J. Strike Reservoir has the next largest reservoir
volume within the study area at 0.25 million acre feet.
Groundwater, tributaries, and reservoirs on tributaries also supply
water, but American Falls reservoir supplies the bulk of irrigation
water demands in the region. Its upstream location as well as its
volume relative to other water storage facilities both contribute
to its dominant role in the regions irrigation water supply.
22
-------
Limited flood control and recreational benefits are associated with
the reservoir since its operation is highly biased towards its
primary purpose of storing irrigation water.
Excluding C. J. Strike and American Falls Reservoirs, the
impoundments that constitute the great majority of Snake River
impoundments are "run-of-the-river" dams. Typically this type of
dam has a short hydraulic detention time and limited storage
capacity. Most of these dams simply serve to raise the elevation
head of the river, either for hydroelectric power generation or
irrigation diversions. Reservoir volumes associated with these
dams are usually relatively small and are more a side effect of
the impoundment than a specific design objective. Lake Walcott
and Milner Pool are typical examples of impoundments designed to
provide elevation head for water diversion rather than water
storage.
Upper and Lower Salmon Falls Dams are examples of
hydroelectric dams on the Snake River. The bulk of the dams found
on the mainstem of the Snake River were constructed primarily for
power production and have few if any secondary benefits associate
d with the impoundment. Idaho Power is responsible for operation
of many of these dams. Control is exercised either indirectly in
cooperation with private and public agencies selling hydroelectric
power or directly by ownership of many of the dams. In the case
of hydroelectric dams, the impoundments serve to raise the
23
-------
hydraulic head to the hydroelectric turbines thereby increasing
power generation. Operation of these dams is directed towards
maximizing hydroelectric power generation.
Water Management Practices
American Falls Reservoir was constructed by the U. S. Bureau
of Reclamation and began storing irrigation water in 1926. To
assure annual filling of this reservoir all other uses or benefits
that could be gained from operation of this dam are subordinated
to the dams primary purpose of storing water for irrigation. Flood
control storage in American Falls Reservoir is an explicit example
of this subordination.
Operating levels in most reservoirs maintain a seasonally
varying flood control storage volume in the reservoir. In
contrast, American Falls Reservoir generally contains a significant
volume of water at the onset of the flood season and must be drawn
down to provide the required flood control storage capacity. This
occurs in only the wettest of years. If spring runoff volumes are
not flood threatening, flows in excess of that necessary to top off
the reservoir are allowed to spill (pers. comm. M. Beus, 1989).
In most years water is stored in American Falls Reservoir at
a maximum rate from the end of one irrigation season to the
beginning of the next. Resulting stream flows are low during most
of this filling season. An informal minimum release of 350 cfs is
24
-------
observed. Actual release rates are based on spring runoff
predictions and the 350 cfs minimum rarely determines reservoir
releases. Thus, releases are low through most of the filling
season except possibly during the spring when a portion of the
annual spring runoff may be spilled from the reservoir. Spills
are infrequent and have not occurred since 1986. Throughout the
irrigation season, releases are made according to irrigation
demands. Water storage is usually in excess of irrigation demands.
Typically 30 percent of the operating storage capacity of American
Falls Reservoir remains in the reservoir at the end of the
irrigation season (pers. comm. M. Beus, 1989).
Water application in excess of crop requirements also
contributes to water quality degradation. Under Idaho water law,
an owner of a water right generally must exercise the full quantity
of his water right to prevent loss or reduction of his allotment.
To avoid potential decreases in their water right apportionment,
many farmers will apply their full apportionment regardless of crop
water requirements. Water markets have been instituted to
alleviate this problem but their use and availability has been
limited (Whittlesey, Hamilton, and Halverson, 1986). Applying
water in excess of crop requirements is sometimes necessary to meet
soil leaching requirements, however in most cases within the study
area it simply results in larger volumes of water lost to deep
percolation and surface runoff.
25
-------
Sediment loads have been shown to increase dramatically with
runoff flow rates from crop land (D. Carter, 1976 and pers. comm.
F. Watts 1979). Larger flow rates increase the availability of
the sediment carrying medium and increase furrow, ditch, and canal
water velocities. Both of these effects of increased water
application tend to exacerbate soil erosion losses.
Water is also wasted or lost by percolation through canal
bottoms as it travels from the point of diversion to its point of
application. Examples of the quantities of water loss and waste
are displayed in Table 1 (pg. 27) . Less than two acre feet of
water per acre is necessary to meet the consumptive use
requirements of most crops cultured in the region. As much as 18.4
acre feet of water per acre of irrigated land is diverted by the
Lowder Slough Irrigation District. This is more than nine times
the probable crop water requirement. An estimated 50,000 to 60,000
additional acres could be irrigated in the Twin Falls area alone
through water conservation and better management practices (pers.
comm. M. McMasters, 1989).
26
-------
Table 1. Selected Diversions During 19S2 Irrigation Year from Snake River
Nar.e
Total
Diverted
(acre-feet )
Area
Irrigated
(acres )
Ac-ft/ac
Diverted
Canals Betveen Irvin and Lorenzo:
Progressive Irr. Dist.
Farmers Friend
Enterprise
Butler Island
Harrison
Rudy Irr. Co.
Lowder Slough
Burgess
Clark & Edwards
East LaBelle
Rigby and Rigby Lateral
Island
W. LaBelle & Long Island
Parks & Levisville
North Rigby
Sunnydell
Lenrobt
Reid
Texas & Liberty
TOTAL
Canals Between Lorenzo and
Butte & Market Lake •
Great Western & Porter
Idaho
Snake River Valley
Reservation
Blackfoot
New Lava Side
Peoples
Aberdeen
Corbett
Riverside
Danskin
Watson
195,500 (a)
116,000
53,300
12,300
146,600
90,000
18,400
291,400
26,100
36,300
56,800
54,500
141,100
106,300
18,500
55,900
47,000
47,100
68,800
1,630,908
Blackfoot:
67,900
212,300
287,600 (a)
177,900
65,000 (a)
102,600
32,200
98,600
283,100
43,100
32,900
54,300
31,800
33,000
10,500
5,200
1,100 '
13,000
5,000
1,000
22,000
1,940
3,000
4,000
5,500
10,500
8,500
1,400
3,780
3,100
5,500
10,000
151,260
20,000
30,220
35,850
20,790
54,770
15,000
6,000
20,000
63,000
6,000
5,000
8,000
3,000
5.9
11.0
11.2
11.2
11.3
1S.O
18.4
13.2
13.5
12.3
14.2
9.9
13.4
12.5
13.2
14.8
15.2
8.6
6.9
10.7
3.4
7.0
8.0
8.6
1.2
6.8
5.4
4.9
4.4
7.2
6.6
6.8
10.6
TOTAL 1,589,480 302,400 5.3
(a) Not including additional water recieved from other sources
Source: Carlson, 1982 in Whittlesey, N., Hamilton, J. ,
and Halverson, P. 1986.
27
-------
Impacts
Eutrophication
Eutrophication of an aquatic system can be caused by a number
of factors that alter the aquatic environment in favor of increased
aquatic growths. For the purpose of this report eutrophication is
defined as the artificially enhanced or increased productivity of
an aquatic system. Eutrophication and subsequent increases in
plant and fish production may be viewed as beneficial impacts in
some water bodies, but it is most commonly viewed as a negative
aspect of nutrient additions to an aquatic environment. Decaying
plant life produces foul odors, algae increase turbidity, and
aquatic weeds can clog canals and water ways. Fisheries may be
impacted by an increased oxygen demand from the larger mass of
decaying organic matter and fish populations tend to shift towards
warm water species and away from the highly prized salmonid game
fish. When the trophic state reaches the levels found through most
of the Snake River, the excessive growths of aquatic weeds and
turbid waters limit the aesthetic value of the river.
Increased temperature or decreased sediment load with a
corresponding increase in light penetration could be responsible
for the eutrophication of a water body, but the most common cause
is an increased supply of a population limiting nutritive
substance. In a nutrient limited system the growth of aquatic
plants and algae is stimulated by the introduction of nutrients.
28
-------
Increases in plant and algae biomass provide increased
opportunities for aquatic animal life, resulting in similar
increases in the biomass of aquatic animal communities. Thus both
plant and animal productivity is stimulated by the introduction of
nutrients in an aquatic system.
Limitation of productivity in the Snake River by substances
other than nitrogen or phosphorus is unlikely due to the large
influx of sediments, pollutants, and dissolved solids to the
system. Carbon or micronutrient limitations would appear to be
highly improbable in a system receiving such a heavy load of
sediments, dissolved solids, nutrients, organic matter, and trace
elements from various sources, however light limitation may be
possible as a result of high turbidity conditions in the river.
To be biologically available for cell growth, nitrogen and
phosphorus must be present in inorganic forms. Phosphorus must be
present as soluble inorganic orthophosphate while nitrogen may be
present as nitrate (N03) , nitrite (N02) ammonia (NH3) , ammonium ion
(NH4) , or gaseous nitrogen (N2) . Ammonia appears to be the
preferred form of nitrogen for consumption by most organisms
(USEPA, 1978). Assuming the Snake River is limited by either
nitrogen or phosphorus, nitrogen to phosphorus (N:P) ratios were
calculated at different locations along the river in an attempt to
determine which of the two is the limiting nutrient. Based on
average inorganic nitrogen and orthophosphate concentrations at
29
-------
several sites in the study area, calculated N:P ratios strongly
suggest a phosphorus limited system (Table 2, pp. 30 & 31).
Phosphate can only be used by algae and aquatic macrophytes
in the orthophosphate form (PO4) . Though some organisms have
developed extra-cellular enzymes or other means of liberating
orthophosphate from organic matter, most aquatic plants and algae
must rely on the availability of inorganic orthophosphate in their
environment. In a river environment, available orthophosphate is
quickly assimilated by plant life and converted to tissue or is
adsorbed onto soil particles, forming relatively insoluble
complexes. Death of an organism eventually results in its
deposition on the bottom of a quiescent portion of the river along
with other phosphorus bound to soil particles. The phosphorus
remains bound to soil particles and in organic matter until it is
chemically or biologically liberated under anaerobic conditions.
Phosphorus contributions to American Falls Reservoir probably
constitute the bulk of phosphorus loading downstream of the
reservoir. Lesser phosphorus loads are supplied by municipal and
industrial point sources, feedlots, and , fish hatcheries. The
availability of this phosphorus in the river may be controlled by
the anaerobic liberation of orthophosphate.
30
-------
Table 2
Nitrogen to Phosphorous Ratios
at Selected Sampling Sites Along the Snake River
Dissolved Inorganic
Snake River, mainstem
Below American Falls Res.
at State Fish Hatchery
Below Minidoka Dam
0.4 mile below
Swan Falls Dam
NO, + N03 NH3 + NH4 PO4
(mg/1) (mg/1) (mg/1) N;P
0.60
0.205
1.127
0.03 0.023 27.4
0.025 0.029 7.9
0.023 0.029 39.7
Hatchery Effluents
Crystal Springs Discharge 2.357
Rim View Raceway 1.610
0.027 0.030 79.5
0.275 0.060 31.4
Tributaries
Billingsley Creek
Below Tupper Grade Bridge 1.065
Above Fisheries Development 1.110
Below Fisheries Development 1.036
0.122 0.066 18.0
0.153 0.055 23.0
0.130 .064 18.2
Rock Creek
Above State Highway 93 1.874
@ Ellis Fish Hatchery 3.250
Near Mouth of Rock Crk. 0.111
0.132 0.049 40.9
0.016 203.1
.0298 3.8
Cedar Draw
@ Rest Area W. of Filer
Below Pole Line Road
1.18
.839
31
0.125 0.041 31.8
0.101 8.3
-------
Table 2 (cont.)
Nitrogen to Phosphorous Ratios
at Selected Sampling Sites Along the Snake River
Dissolved Inorganic
N02 + NO3 NH3 + NH4
PO,
Irrigation Drainage
Major Drain on E. Side
of Rock Creek
Q-Coulee @ Highway 30/93
near KIFI radio
Main Drain @ 400 S. Rd.
K-Coulee @ Golf Course
near mouth
Perrine Coulee @ Mouth
Perrine Coulee above
Highway 30
South Drain
settling pond @ check
(mg/1)
0.112
2.68
2.646
2.56
1.77
0.685
0.200
(mg/1) (mg/1) N;P
0.030 3.7
0.048 0.031 88.0
1.437 .043 95.0
0.238 0.041 68.2
0.063 28.1
.046 14.9
0.100 0.015 20.0
Source: USEPA STORET database retrieval 05/89
NOTE: Concentration values are based on averages. Variations in
the number, date, and agency collecting samples may taint the
accuracy of some values.
32
-------
Though application of river water to irrigated crop land has
been shown to reduce phosphorus concentrations found in irrigation
tailwaters returning to the river, the phosphorus content of these
flows cannot be ignored. Assuming a phosphorus limited system and
negligible phosphorus contributions downstream of American Falls
Reservoir, the influx of phosphorus to American Falls Reservoir
probably constitutes the single largest factor responsible for
eutrophication of the Snake River.
Nitrogen contributions to the Snake River include nitrates in
spring flows, limited instances of nitrogen fixation by blue green
algae, and ammonia and nitrates in irrigation returns, animal
wastes from feedlots and hatcheries, and municipal and industrial
point source discharges. Based on biologically available
orthophosphate concentrations throughout most of the river,
abundant nitrogen is available to meet the nutritional requirements
for photosynthetic production.
Impoundments
The continual flushing effect of rivers as they flow towards
the Pacific ocean is a very fortunate characteristic of the Snake
River. If the nutrient loading, sunlight, and water temperature
conditions found in the river were present for a lentic body of
water an extremely high trophic state would likely result. A lotic
33
-------
environment is vital to water quality maintenance in the Snake
River for several reasons. Besides continually aerating the water
as it assimilates and washes pollutants from the system, flowing
water maintains a well mixed water column and inhibits the growth
of algae and aquatic macrophytes.
Dissolved oxygen is necessary for the survival of most forms
of aquatic life. A continual supply of oxygen rich water from the
surface is made possible by the mixing of river water. In the
Snake River, mixing also inhibits the onset of anaerobic conditions
in sediments and water near the river bottom which can result in
severe internal phosphorous loading.
Impounded water is especially susceptible to anaerobic
conditions because it is more likely to stratify under quiescent
conditions. Once stratified, dissolved oxygen in the lower layers
is quickly depleted by respiring organisms involved in the decay
of the abundant organic matter that settles out of the water
column. Anaerobic conditions liberate phosphorus and release it
in the biologically available orthophosphate form from the
sediments and decaying organic matter.
Most reaches of the Snake River, including many of the
impoundments, can be considered fully mixed or polymictic. When
stratification does occur it is usually rather weak and easily de-
stabilized by wind or turbulent mixing of river currents. When the
34
-------
orthophosphate is returned to the photic zone by destratification
and mixing, it is again available for photosynthetic production.
As a result, such autochthonous phosphorus loading can continually
release phosphorus to a water body.
A certain amount of orthophosphate liberation probably occurs
in small anaerobic interstitial voids of sediments and is
eventually released to the water column. Liberation of phosphorus
generally occurs on a much greater scale under stratified
conditions than would otherwise be possible in anaerobic sediment
voids. River productivity may be repeatedly stimulated by internal
phosphorus loading in the numerous river impoundments encountered
along the river. Milner Dam, for example, forms a shallow pool
with a relatively low detention time compared to most impoundments.
Ordinarily it would be difficult to stratify a water body with
these characteristics, however severe algal blooms have been noted
as a result of stratification in Milner Pool (J. Yearsley, 1989).
Aeration capacities of impounded waters are also substantially
reduced by dams and impoundments on the Snake River. In a free
flowing river the turbulent mixing action between the high oxygen
content surface waters and lower oxygen content deeper waters of
the river tends to provide a relatively uniform supply of oxygen
throughout the water column. Rapids and waterfalls are especially
important supplies of oxygen to the river.
35
-------
Rapids and waterfalls are also ideal sites for hydroelectric
dams and diversions since steeper gradients provide the greater
available drop in elevation at these sites that is required for
hydroelectric power production. Hydroelectric diversion dams allow
some minimum flow to continue through the rapids or waterfall but
divert a substantial portion of the flow through a penstock to
turbines when flows are sufficient to permit diversions. The flow
passing through the rapids or falls is often fully aerated
(saturated oxygen levels) while that flowing through the penstock
and turbines is only minimally aerated by turbulence in the
tailwaters.
Impoundment dams are installed at many falls or rapids sites
to raise the elevation head on the turbines. The backwater
upstream of these dams is slowed and often becomes stratified under
these relatively stagnant flow conditions. Falls or rapids in
these areas are drowned by the elevated water surface upstream of
the dam and their aeration capability is lost. Diversion dams have
a similar impact on the river but generally to lesser degree.
Slowing or stagnation of flowing waters shifts the river away
from the free flowing lotic environment towards a lentic pool or
lake condition. Aquatic macrophytes that normally could not
survive and propagate in swifter free flowing waters quickly
establish large populations in the nutrient rich slow moving
waters. Animal populations are similarly affected by the change
36
-------
in environment which tends to favor warm water and other less
desirable species.
The increase in organic matter as a result of impoundments
and eutrophication in the Snake River results in larger masses of
decaying matter throughout river, particularly in the backwater
created by impoundments. Tendencies toward stratification,
increased oxygen demands from decaying organic matter, and reduced
mixing in the lentic areas of impoundments create anaerobic
conditions at many of the dam sites along the river. Water
withdrawal or release from the de-oxygenated or anaerobic
hypolimnetic portions of the pool may cause low dissolved oxygen
conditions to persist for many miles below an impoundment before
oxygen levels recover. Releases from American Falls Reservoir are
believed to be occasionally low or void of oxygen as a result of
such withdrawals, (pers. comm. W. Poole, 1989).
Sediment carrying capacities are decreased upstream of
impoundments. As the turbulence of river currents is dissipated
in the slowing moving backwater of impoundments, the river's
ability to entrain and suspend material is reduced or lost and
suspended matter settles out. Typically larger and denser
particles settle out first. Conversely the sediment deficient
water released downstream of a dam flows faster, entraining
sediment to correct the deficit. The net result is deposition of
37
-------
suspended material upstream of a dam and scouring of the river
bottom downstream of the dam.
Temperatures tend to fluctuate over a greater annual range
due to the presence of numerous impoundments on the Snake River.
The increase in surface area provides greater opportunities for
radiation, absorption, and transfer to and from the river which
tends to raise summer river temperatures and lower winter water
temperatures. Maximum water temperatures have been established
for impoundments along the river by state and federal regulatory
agencies to protect salmonid fish populations which have a low
tolerance for warm water temperatures. Temperature effects are
often cumulative. Heat absorbed at one site may not cause
temperatures to exceed the allowable temperature at one site but
the cumulative effect of numerous reservoirs could raise
temperatures beyond maximum levels in all reservoirs beyond a some
downstream point. A secondary effect of warmer water is the
lowered dissolved oxygen carrying capacity relative to cold water.
Migratory fish populations are impacted in numerous ways by
dams and impoundments. Besides presenting a substantial if not
insurmountable obstacle to migration, many spawning sites along
the river are destroyed or degraded by the accumulations of silt
and other sediments that settle out in the quiescent backwater of
impoundments. Warmer waters are a less suitable environment for
38
-------
this valuable fishery and the lower oxygen content of warm water
hinders respiration.
Water Management Impacts
Water management impacts result from a lack of conservation
of water resources. The two primary contributions to these impacts
are irrigation diversions and uses on crop lands and filling rates
and methods in storage reservoirs. In general the problems with
these practices is that they limit or remove in-stream flows which
would otherwise be available for dilution of wastes.
Operation of American Falls Reservoir limits the total
benefits that could be gained from the water that flows into it by
limiting releases. In addition to diluting wastes, larger releases
carry a larger total volume of dissolved oxygen relative to a given
BOD loading. Larger flows may also be capable of dissolving larger
volumes of oxygen due to the greater presence of the carrying
medium (water) as they flow through rapids or other turbulent
reaches of the river. Thus, during most of the filling season, the
ability of the river to assimilate wastes is lowered because of the
low release rates. In contrast, the assimilative capacity of
spilled spring runoff could be stored for later release.
39
-------
Implementation of this method of water quality improvement
simply requires a change in the operation of American Falls
Reservoir and other reservoirs to allow slower filling and greater
releases. The filling and release rates could be adjusted
depending on predicted spring runoff to assure an adequate volume
of water would be stored to meet demands during the irrigation
season.
Irrigation efficiencies are low in the study area, as
evidenced by Table 1. In some cases as little as 20 percent or
less of the water diverted from the stream is used to satisfy crop
consumptive use and evapotranspiration. Water diversions should
be minimized so that only as much water as is necessary to meet
leaching requirements, crop consumptive use, and conveyance losses
is removed from the river. Conveyance losses in canals are
unavoidable unless canal liners are installed, but deep percolation
and surface runoff could be substantially reduced.
Elimination of surface runoff and reduction in percolation
losses would virtually eliminate surface flow contributions of
nutrients, sediment, pesticides, bacteria, and BOD from feedlots
and irrigated agriculture. Pollutant loadings from contaminated
groundwater that reaches the river via spring flows would also be
substantially reduced. The water saved could be left in the stream
and used to generate power and increase the dilution and
assimilative capacity of the river or used for irrigation of
40
-------
additional lands. Water quality improvements would probably be
manifest primarily as lower turbidities and suspended sediment
concentrations, diminished oxygen deficits, and reduced nutrient
loadings. Heavy nutrient loading from other less controllable
sources may compensate or overshadow reductions in nutrient
loadings from these sources. Consequently, noticeable reductions
in aquatic plants and algae blooms may not occur. Water quality
improvements made possible by water conservation measures would
appear to be cost effective irrespective of benefits associated
with reductions in nutrient loadings.
From a strictly economic viewpoint, the lower marginal value
of water used for irrigation compared to the marginal value of
hydroelectric power renders much of the use of water for irrigation
as wasteful. Where water banks have been available for the
transfer of water rights and apportionments, Idaho Power has been
the primary buyer of excess irrigation water. Water excesses are
left in stream and used to generate electricity as it passes
through the numerous dams operated by Idaho Power. Other power
producing facilities on the Snake River also benefit from these
purchases by Idaho Power (Whittlesey, Hamilton, and Halverson,
1986).
Several advantages arise from in-stream use of water for power
generation. The first is that power production is a non-
consumptive use of water allowing the water to remain in the river
for the dilution and assimilation of wastes. Many of the
41
-------
detrimental aspects of water impoundments such as stratification,
sedimentation, decreased mixing, and temperature increases are
lessened with larger flows. Finally, the net economic output of
the state of Idaho could be increased by using water for the more
valuable power production over the lower value crop irrigation.
Through the use of a water bank for the transfer of excess
irrigation water to meet firm power demands Whittlesey, Hamilton,
and Halverson estimate that even after subordinating irrigation
demands to firm power hydroelectric generation agricultural
production would remain intact in all but the driest years. "The
program analyzed would reduce average agricultural income about
$2.50 per acre while the value of hydropower produced would be
about ten times this amount." (Whittlesey, Hamilton, and Halverson,
1989) .
42
-------
Options for Water Quality Improvement
Probably the most effective and least expensive methods of
improving water quality in the Snake River involve methods of
limiting or eliminating the pollutant loading to the Snake River
or by improving water use and storage efficiencies that allow a
larger portion of the available water to be retained in the stream.
Implementation of these methods could be instituted voluntarily as
part of a state or federal regulatory program for the region.
Complications from second and third party impacts would
undoubtedly arise. For instance, reductions in deep percolation
would likely reduce the availability local groundwater relative to
the abundant groundwater resources currently available. Purchases
of excess irrigation water by hydroelectric power producers would
require direct compensation to persons giving up surface water
rights and compensation of groundwater users who would indirectly
be impacted.
Alterations in the filling method of American Fall and other
reservoirs involves a certain amount of risk since spring runoff
predictions could overestimate the actual amount of runoff.
Releases may then be too great to assure filling of the reservoir.
Insufficient volumes of stored water would result in losses to
farmers. Most of these losses in farm income could be limited or
43
-------
eliminated with crop insurance, perhaps state or federally
sponsored in the area.
Most of the following options for water quality improvement
have been mentioned or alluded to in previous portions of this
report. The more significant options are enumerated below.
1. Creation of a water bank for water transfers to allow for
increased water use efficiencies between competing water users
in the region.
2. Elimination or reduction of pollutant laden irrigation surface
runoff and deep percolation returns to the Snake River.
3. Improvement of irrigation efficiencies by reducing deep
percolation and surface runoff so as to retain greater flow
rates in the Snake River.
4. Alteration of rule curves and reservoir operations in water
storage facilities to provide greater volumes of water for
water quality enhancement and protection.
5. Use of fish feeds with a minimal phosphorus content could
limit stimulation of aquatic plant and algae growth in the
Snake River by from phosphorous rich fish hatchery effluent.
44
-------
Bibliography
References Cited
Benefield, L. D. and Randall, C. W. 1980. Biological Process
Design for Wastewater Treatment. Prentice-Hall, Inc. Englewood
Cliffs, NJ. 526 pp.
Brown, M. J., Carter, D. L., and Bondurant, J. A. 1974. Sediment
in Irrigation and Drainage Waters and Sediment Inputs and
Outputs for Two Large Tracts in Southern Idaho. Journal of
Environmental Quality, Vol. 3, No. 4, 1974. 5 pp.
Carter, D. L., Bondurant, J. A., and Robbins, C. W. 1970. Water
Soluble NO3-Nitrogen, PO4-Phosphorus, and Total Salt Balances
on a Large Irrigation Tract. U. S. Department of Agriculture,
Idaho Experiment Station. Kimberly, ID. 5 pp.
Federal Water Pollution Control Administration, Northwest Region.
1968. Water Quality Control and Management: Snake River Basin.
Portland OR. 72 pp.
Idaho Department of Agriculture, Idaho Crop and Livestock reporting
Service. 1989. Idaho Agricultural Statistics. Boise, ID.
approx. 60 pp.
Idaho Department of Health and Welfare, Division of Environmental
Quality and Idaho Department of Fish and Game. 1989. Southwest
Basin Status Report. Boise, ID. 9 pp.
. 1989. Upper Snake River Basin Status Report. Boise,
ID. 9 pp.
Idaho Department of Health and Welfare, Division of Environmental
Quality, Water Quality Bureau. 1989. Rock Creek Rural Clean
Water Program, Comprehensive Water Quality Monitoring Annual
Report 1988. Prepared by Clark, W. H. Boise, ID. 316 pp.
Metcalf and Eddy Inc. 1979. Wastewater Engineering: Treatment/
Disposal/Reuse. McGraw-Hill Inc. San Francisco, CA. 920 pp.
Naylor, D. V. and Busch, J. R. 1973. Effect of Irrigation,
Fertilization, and Crop Cultural Practices on Water Quality.
Idaho Water Resources Research Institute, Moscow, ID. approx.
75 pp.
Pacific Northwest River Basins Commission, Hydrology and Hydraulics
Committee. 1976, River Mile Index: Snake River, Part II Snake
River above Weiser. Portland, OR. 49 pp.
-------
Parametrix Inc. 1979. Nutrient Analysis of the Snake River and
its Major Tributaries from Above Palisades Reservoir in Wyoming
to Weiser, Idaho—Rivermiles 941 to 351. Bellevue, WA. approx.
100 pp.
Tetra Tech, Inc. 1976. Water Quality Assessment and Projections-
Snake River, Idaho. Lafayette CA. approx. 75 pp.
U. S. Department of the Interior, Federal Water Quality
Administration, Northwest Region. 1970. Examination of the
Waste Treatment and Disposal Operation at the National Reactor
Test Station, Idaho Falls, Idaho. Portland, OR. approx. 120
pp.
U. S. Environmental Protection Agency. 1976. The Influence of
Land Use on Stream Nutrient Levels. Prepared by J. M.
Omernik. USEPA Office of Research and Development, Corvallis,
OR. 106 pp. EPA-600/3-76-014
U. S. Environmental Protection Agency. 1989. STORET data base
retrievals. USEPA, Region X. Seattle, WA.
Whittlesey, N., Hamilton, J., and Halverson, P. 1986. An Economic
Study of the Potential for Water Markets in Idaho. Idaho Water
Resources Research Institute. Moscow, ID. 136 pp.
Personal Communications
Beus, M. November 28 and 30, 1989. U. S. Bureau of Reclamation,
Burley, ID. Telephone conversations.
Brannen, E. November 27, 1989. Professor. University of Idaho,
College of Forestry and Wildlife Resources, Moscow, ID.
Telephone conversation.
Falter, C. M. Fall, 1989 Professor. University of Idaho,
College of Forestry and Wildlife Resources, Moscow, ID.
Lectures and personal or telephone conversations.
Klahr, T. November 17, 1989. Idaho Department of Health and
Welfare, Division of Environmental Quality, Southwest Region,
Boise, ID. Telephone conversation.
McMasters, M. August and September, 1989. Idaho Department of
Health and Welfare, Division of Environmental Quality,
Southcentral Region, Twin Falls, ID. Telephone conversations
and meetings in Twin Falls.
-------
Poole, W. November 20, 1989. Idaho Department of Health and
Welfare, Division of Environmental Quality, Southeast Region,
Pocatello, ID. Telephone conversation.
Watts, F. Fall, 1989. Professor. University of Idaho, College
of Engineering. Moscow, ID. Lectures.
Yearsley, J. May and August, 1989. U. S. Environmental
Protection Agency, Region 10. Seattle WA. Meetings and
telephone conversations.
Personal Communications and References Consulted but not Cited
Clark, W. October 10, 1989. Idaho Department of Health and
Welfare, Division of Environmental Quality, Water Quality
Bureau. Boise, ID. Telephone conversation.
Bushnell, V. C. 1969. Eutrophication Investigation of American
Falls Reservoir. U. S. Bureau of Reclamation, Pacific Northwest
Region, Boise, ID. approx. 150 pp.
Carter, D. L. 1980. The Impact of Irrigation on Groundwater
Quality. Proceedings of a Special Conference on Irrigation and
Drainage - Today's Challenges. July 23-25, 1980. Boise, ID.
Carter, D. L., Robbins, C. W., and Bondurant, J. A. 1973. Total
Salt, Specific Ion, and Fertilizer Element Concentrations and
Balances in the Irrigation and Drainage Waters of the Twin Falls
Tract in Southern Idaho. U. S. Department of Agriculture,
Western Region, Agricultural Research Service. Kimberly, ID.
37 pp.
Carter, D. L., Robbins, C. W., and Bondurant, J. A. 1974.
Phosphorous Associated With Sediments in Irrigation and Drainage
Waters for Two Large Tracts in Southern Idaho. Journal of
Environmental Quality Vol 3, No. 3, July-September, 1974. 3 pp.
Dixon, J. E., Lingg, A. J., Naylor, D. V., Hinman, D. D., and
Stephenson, G. R. 1982. Non-point Pollution Control for
Rangeland Wintering: Livestock Operations (Ground Cover) . Idaho
Water Resources Research Institute. Moscow, ID. 31 pp.
Goldman, C. R. and Home A. J. 1983. Limnology. Mcgraw-Hill,
Inc. San Francisco, CA. 464 pp.
-------
Hackett, B., Pelton, J., and Brockway, C. 1986. Geohydrologic
Story of the Eastern Snake River Plain and the Idaho National
Engineering Laboratory. United States Department of Energy,
Idaho Operations Office, Idaho National Engineering Laboratory.
Idaho Falls, ID. 32 pp.
Henderson-Sellers, B. and Markland, H. R. 1987. Decaying Lakes:
The Origins and Control of Cultural Eutrophication. John Wiley
and Sons. Great Britain. 254 pp.
Johnson, J. M., Odlaug, T. O., Olson, T. A., and Ruschmeyer, O. R.
1970. The Potential Productivity of Fresh Water Environments
As Determined By An Algal Bioassay Technique. Water Resources
Research Center University of Minnesota Graduate School.
Minneapolis, Minnesota. 79 pp.
Likens, G. E. 1972. Nutrients and Eutrophication: The Limiting-
Nutrient Controversy. American Society of Limnology and
Oceanography, Inc. Lawrence, Kansas. 328 pp.
Middlebrooks, E. J., Maloney, T. E., Powers, C. F., and Kaak, L.
M. 1969. Proceedings of the Eutrophication-Biostimulation
Assessment Workshop. Federal Water Pollution Control
Administration. Corvallis, OR. 281 pp.
Minshall, G. W. and Rose, F. L. 1972. A Pilot Program to
Determine the Effect of Selected Nutrients (Dissolved Organics,
Phosphorous, and Nitrogen) on Nuisance Algal Growth in American
Falls Reservoir. Idaho Water Resources Research Institute,
Moscow, ID. approx. 75 pp.
J. M. Montgomery Engineers. 1979. State of Idaho Summary 208
Water Quality Management Plan. Idaho Department of Health and
Welfare, Division of Environmental Quality, Water Quality
Bureau, Boise, ID. approx. 100 pp.
Middlebrooks, E. J., Falkenborg, D. H., and Maloney, T. E. 1974.
Modeling the Eutrophication Process. Ann Arbor Science. Ann
Arbor, MI. 228 pp.
Middlebrooks, E. J., Falkenborg, D. H., and Maloney, T. E. 1976.
Biostimulation and Nutrient Assessment. Ann Arbor Science.
Ann Arbor, MI. 390 pp.
Organization for Economic Co-operation and Development. 1970.
Scientific Fundamentals of the Eutrophication of Lakes and
Flowing Waters, with Particular Reference to Nitrogen and
Phosphorus as Factors in Eutrophication. Paris, France. 159
pp.
-------
Robbins, C. W. and Carter, D. L. 1978. Salt Outflows from New
and Old Irrigated Lands. Soil Science Society of America
Journal Vol 42, No. 4, July-August, 1978. Madison, WI. 5 pp.
Robbins, C. W. and Carter, D. L. 1980. Nitrate-Nitrogen Leached
Below the Root Zone During and Following"Alfalfa. Journal of
Environmental Quality Vol. 9, No. 3, July-September, 1980. 4
pp.
U. S. Environmental Protection Agency. 1973. Nitrogen Sources
and Cycling in Natural Waters. Prepared by P. L. Brezonik and
C. F. Powers. USEPA Office of Research and Development,
Corvallis OR. approx. 110 pp. EPA-600/3-73-002
. 1977. Nonpoint Source - Stream Nutrient Level
Relationships: A nationwide Study. USEPA, Office of Research
and Development. Corvallis, OR. 151 pp. EPA-600/3-77-105
U. S. Environmental Protection Agency. 1978. Summary Analysis of
the North American (U. S. Portion) OECD Eutrophication Project:
Nutrient Loading—Lake Response Relationships and Trophic State
Indices. Prepared by W. Rast and F. Lee. USEPA Office of
Research and Development, Corvallis, OR. approx. 230 pp. EPA-
600/3-78-008
------- |