Green River
and
Flaming Gorge Reservoir
Post Impoundment Investigations
1967
Addendum
Progress Report No. 4, Job No. 1 B
Fishery Investigations, Flaming Gorge Unit
Section 8 Progress, Flaming Gorge Unit
Colorado River Storage Project
Fishery Survey of Fontenelle Reservoir • and the Green River Downstream to Flaming Gorge Reservoir
„Wyoming Game and Fish Commission - James B. White, TABLE OF CONTENTS Page Abstract 1
Introduction 4
Methods 6
Results, Fontenelle Reservoir 9 Chemical and Physical 9 Temperature 9 Dissolved Oxygen 9 Alkalinity 10 Hydrogen Ion 11 Total Hardness 11 Turbidity 12 Electrical Conductivity 12 Bottom Fauna 12 Plankton 1 3 Fishery 15 Composition, Abundance, and Distribution 15 Rainbow Trout 16 Brown Trout 17 Whitefish 18 Flannelmouth Sucker 19 Carp 20 Bonytail Chub 20 Utah Chub 21 Bluehead Sucker 21 Forage Fish 21 Harvest 21 Food Habits 21
Results, Green River Section I 24 Chemical and Physical 24 Turbidity 25 Hardness 25 Bicarbonate 25 Sulfate 25 Chloride 26 Electrical Conductivity 26 Hydrogen Ion 26 Temperature 27 Bottom Fauna 27 Fishery 28
Section II Chemical and Physical 29 Turbidity 31 Hardness 31 Bicarbonate 31 Sulfate 31 TABLE OF CONTENTS cont'd:
Section II Chloride 32 Electrical Conductivity 32 Hydrogen Ion 32 Temperature 32 Bottom Fauna 32 Fishery 33 Composition, Abundance and Distribution 34 Length, Weight and Condition 34 Food Habits 37 Age Composition 38
Section III, Fontenelle Reservoir Chemical and Physical 39 Turbidity 41 Hardness 41 Bicarbonate 41 Sulfate 42 Chloride 42 Electrical Conductivity 42 Hydrogen Ion 42 Temperature 43 Bottom Fauna 43 Fishery 44 Composition, Abundance and Distribution 44 Length, Weight and Condition 45 Food Habits 46 Age Composition 46
Section IV Chemical and Physical 49 Bottom Fauna 51 Fishery 52 Exploitation of the Green River Fishery 52 Trout Movement 54 Spawning 55
Discussion 55 LIST OF TABLES
Table Page
1. Summary of Trout Stocking in the Green River and Fontenelle Reservoir, 1963 - 1966 ...... 5
2. Food Habits of 50 Rainbow Trout and 20 Brown Trout from Fontenelle Reservoir, 1965 and 1966 ...... 23
3. Bitter Creek Water Composition on March 21, 1966, during the Lowland Runoff (in ppm) ...... 24
4. Alkali Creek Chemical Composition ...... 29
5. Chemical Composition of the Big Sandy River...... 30
21, 1966, 6. Chemical Composition of Dry Creek on March ...... (in ppm) 30
(K) 7. Mean Length, Weight and Condition Data for Fish...... in Section II 35
8. Food Items of 51 Rainbow Trout Stomachs from Section II, Green River, 1965 - 1966 (all sizes combined). — 36
9. Average Lengths for Each Rainbow Trout Age Class in Section II ... 38
10. Water Chemistry of Slate Creek (in ppm) ... 39
11. Water Chemistry (in ppm) and Physical Data for East Side Flume Creek and the Green River upstream from the Mouth of Flume Creek ... 40
12. Average, Length, Weight and Condition of Fish in Section III during Fiscal Years 1966 and 1967 ... 47
13. Food Items of 32 Rainbow Trout Stomachs from Section III, Green River, 1965 - 1966 ...... 48
14. Average Lengths for Each Rainbow Trout Age Class in Section III...... 49
15. Mean and Extreme Values (ppm) of Green River Water Chemistry, Section IV, (Names Hill Only), 1965 - 1967 50
16. Green River Creel Census Summary, 1966 ... 60
17. Aerial Fishermen Counts on the Green River from Flaming Gorge Reservoir to Fontenelle Reservoir during June, July, August and September, 1966 ... 61 LIST OF FIGURES
Figure Page
1. Map of the Green River Study Area Showing Sections and Locations of Benthic Sample Stations ... 62
2. Monthly Surface Area at Fontenelle Reservoir from July, 1965 to July, 1967 ... 63
3. Mean Weekly Discharge of the Green River at the Fontenelle Dam Gage from July, 1965 to September, 1966 .... 64
4. Map of Fontenelle Reservoir Showing Maximum (B) and Minimum (A) Water Levels .... 65
5. Fontenelle Reservoir Water Chemistry as Related to Depth in August, 1965 .... 66
6. Seasonal Fluctuations in Fontenelle Reservoir Water Chemistry from August, 1965 through May, 1967 .... 67
7. Plankton Abundance in the Surface to Ten Foot Strata of Fontenelle Reservoir from August, 1965 to May, 1967 ...... 68
8. Vertical Distribution of Plankton in Fontenelle Reservoir in August, 1965 and 1966 ...... 69
9. Composition of the Fontenelle Reservoir Fish Popula- tion as Indicated by Gill Net Catches in the Fiscal Years 1966 and 1967. (July 1 to June 30) ...... 70
10. Length Frequency of Rainbow Trout in Fontenelle Reservoir as Indicated by Gill Net Catches in Fiscal Years 1966 and 1967 (July 1 to June 30) 71
11. Mean Lenghts attained at Various Ages by Rainbow and Brown Trout in Fontenelle Reservoir. Age as determined from Scales and Otholiths taken from Gill Net Caught Trout .... 72
12. Number and Volume of Organisms in Square Foot Bottom Samples taken at Station 1 from October, 1965 through April, 1967 ....73
13. Composition of Square Foot Bottom Samples taken at Station 1 from October, 1965 through April, 1967... 74
14. Number and Volume of Benthic Organisms in Square Foot Samples Taken at Station II from October, 1965.... through April, 1967 75 List of Figures cont i d: Page 15. Composition of Square Foot Bottom Samples taken at Station II from October, 1965 through April, .... 1967 76
16. Composition of the Fish Population Section II of the Green River as indicated by sampling during the Fiscal Years 1966 and 1967 (July 1 to June 30). 77
17. Number and Volume of Benthic Organisms in Square Foot Samples taken at Station III from October, ...... 1965 through April, 1967 78
18. Composition of Square Foot Bottom Samples taken at Station III from October, 1965 through April, 1967 .....79
19. Composition of the Fish Population Section III of the Green River as indicated by Samples during Fiscal Years 1966 and 1967. (July 1 to June 30 .... 80
20. Number and Volume of Benthic Organisms in Square Foot Samples taken in Section IV from September, 1965 through April, 1967 ...... 81
91. Composition of Square Foot Samples taken at Station IV from September,1965 through April, 1967 .... 82
92. Number and Volume of Benthic Organisms in Square Foot Bottom Samples taken at Station V from August, 1965 through April, 1967 .... 83
23. Composition of Square Foot Bottom Samples taken at Station V from August, 1965 through April, 1967.0 .. 84
24. Dominant Phyto and Zoo-plankters of the Upper 10 Feet of the Pelagic Zone at Fontenelle Reservoir from August 10, 1965 to May, 1967 .... 85 LIST OF APPENDICES
APPENDIX PAGE
1 Fontenelle Reservoir Water Chemistry 9A
2 Fontenelle Reservoir Bottom Fauna 12A
3 Fontenelle Reservoir Plankton 13A
4 Fontenelle Reservoir Fish Condition Factors 17A
5 Green River Water Chemistry 24A
6 Invertebrate Samples, Green River Section 11 27A
7 Invertebrate Samples, Green River Section II 32A
8 Invertebrate Samples, Green River Section III 43A
9 Invertebrate Samples, Green River Section IV 51A
10 Invertebrate Samples, New Fork River 51B ABSTRACT
The biota, chemistry and physical regimens of Fontenelle Reservoir and
the Green River were sampled from 1965 to 1967. Fontenelle Reservoir was
found to be a typical, small, western, alkaline reservoir. When full, the
reservoir had a chemical stratification, but no thermocline. Bottom waters
of the reservoir were nearly anerobic with relatively high carbon dioxide
concentrations. Mougeotia and cladocerans were the principal plankters at
that time. Tendipedidae was always the principal bottom organism.
After the reservoir was reduced to minimum pool in September, 1965, the
chemistry was monotonous and homothermal with only seasonal variations in
hydrogen ion (near neutral in winter) and carbon dioxide (high in winter).
Oxygen, bicarbonate, and total hardness were comparatively stabile seasonally.
Diatoms were the dominant phyto-plankters; while, copepods, rotifers and
cladocerans were the dominant zoo-plankters at different times. Several
species of aquatic plants (Elodea, Potomogeton and Myriophyllum) became
well established in the reservoir shoal areas after draw-down.
Rainbow and brown trout comprised about 25 percent of the fish fauna
in FY 1967. Salmonid numbers appear to be decreasing, while cyprinids and
catostomids apparently are increasing. Gill net catch-per-hour rates
increased in FY 1967 for rainbow trout, carp, and flannelmouth suckers.
Brown trout and whitefish catch rates decreased. Utah and bonytail chubs were rare in gill net catches. Various small cyprinids and immature cat-
ostomids (forage fish) were common in the shoal areas. Gill netted rainbow
trout were smaller in FY 1967. Length of rainbow trout at year V was 464 mm;
length of brown trout at year VII was 510 mm. Excluding organic debris, midge
larvae were the principal item found in rainbow trout stomachs, while scuds
and fish were most common in brown trout stomachs.
-1- Fontenelle Reservoir greatly influenced its tailwater, the Green River, as a barrier to fish migration, as a factor affecting water temperature and as an artificial control of water flow. Flooding, resulting from the 1965 reservoir draw-down, scoured the river and reduced fish stocks. The fish food and plants apparently recovered within a year of the flood. Downstream from the dam, Tendipedidae was the dominant organism in the post-flood period; bottom fauna population peaks occurred in spring and/or fall. Upstream, the benthic fauna peaked in late fall or winter and was dominated by
Tendipedidae or Ephemerella.
The Green River was found to be more alkaline and mineral laden downstream from the confluence of the Big Sandy River. The river seems to decrease in productivity below Big Island because of possible marginal summer temperatures, less fish food and poorer trout habitat. The relatively cool river water near Fontenelle Dam may be attracting trout since numbers of rainbow trout decreased drastically downstream from the Big Sandy River and flannelmouth suckers were the most abundant species in FY 1967 samples. The suckers decreased in abundance, while the salmonids remained relatively stabile, in the area between the dam and the Big Sandy River.
The area between the dam and Big Island had a fisherman catch-per-hour rate of 0.29 trout, from May to September, 1966. Mean length of rainbow trout was 342 mm as opposed to a catch rate of 0.54 trout-per-hour and a size of 283 mm below Big Island Bridge. Statistical analysis of the fisherman catch indicated that the lower area harvest was from a population of smaller size than in the upper area.
Green River City, Big Island and the area adjacent to Fontenelle Town appear to have the heaviest fisherman use. Fishing pressure was heaviest in July, on
-2- holidays, and in the upper area. Most of the non-residents contacted were from Colorado and Utah.
Recaptures of tagged rainbow trout released in the river show that 95 percent were caught within five miles of the planting site. Upstream and downstream movements were about equal. In Flaming Gorge Reservoir, 93 percent of the tagged rainbow trout released were caught within 50 miles of the release site. Only down reservoir movement occurred.
There was some evidence of trout spawning in the river near Fontenelle.
-3- INTRODUCTION
The lower Green River drainage, with its two reservoirs, Flaming Gorge and Fontenelle, has developed into a major sport fishing and general recrea- tion area. Although Flaming Gorge Reservoir has received the bulk of the pressure, the upstream Green River and Fontenelle Reservoir have attracted considerable fisherman use. This report concerns only work done on the
Green River upstream from Flaming Gorge Reservoir. The study was financed by Federal funds allocated under Section 8 of the Colorado River Storage
Project and was conducted as part of the Flaming Gorge Reservoir Investigations.
Information in this report also includes data collected from Fontenelle Res- ervoir proper, and parts of the Green and New Fork rivers of tributary importance to Fontenelle Reservoir.
Considerable work was done on the Green River prior to the present study.
Bosley (1960) conducted a pre-impoundment study of the lower Green River flora and fauna. Following his recommendations, the Green River was treated with rotenone to depress undesirable fish populations (Binns, et al, 1963). The river was also studied in a pre- and post-treatment investigation of the aquatic fauna (Binns, 1965 and 1967). A preliminary report of findings from the present study was made by Binns (1966).
The purpose of the present river study is to investigate the physical, chemical and biological regimens of the Green River and Fontenelle Reservoir in an attempt to discover the inter-relationships that may exist between the river and the two reservoirs, especially as these inter-relationships may influence the fishery. This completion report covers the period from July,
1965 to June,1967.
The study area has been described in detail in past reports (Bosley, 1960;
-4- Binns, 1965, 1966 and 1967). Basically, the area is characterized by the low precipitation, the alkaline, and easily eroded soils, and the harsh climatic conditions typical of a northern shrub desert.
The Green River proper, between the two reservoirs, was heavily stocked with trout following the 1962 rotenone treatment. Fontenelle
Reservoir also was stocked after impoundment (Table I).
Table I. Summary of Trout Stocking in the Green River and Fontenelle Reservoir, 1963 - 1966
FONTENELLE RESERVOIR GREEN RIVER Year Rainbow Trout Rainbow Trout Brown Trout
1963 0 700,000 0
1964 7,900 921,000 0
1965 440,000 60,000 386,000
1966 0 178,621 386,855
-5- METHODS
For the purposes of this investigation, the Fontenelle Reservoir tailwater has been divided into three sections based on physical and chemical characteris- tics of the river between the two reservoirs (Figure 1). Section I extends from the head of Flaming Gorge Reservoir to the mouth of Bitter Creek, near Green
River city; Section II covers the area upstream from the Bitter Creek confluence to the mouth of Big Sandy River; Section III is the remainder of the tailwater from Big Sandy River to Fontenelle Dam. A fourth section was also established in that part of the Green River above Fontenelle Reservoir and extending up the New Fork River to the vicinity of the town of Boulder. This area was included for continuance of post-rotenone-treatment fish food studies and for investigation of carp migration from Fontenelle Reservoir.
Fontenelle Reservoir was completely filled by the 1965 spring run off
(Figure 2). Unfortunately, a leakage problem necessitated the almost complete evacuation of the reservoir in September, 1965, to prevent a potential threat to the dam itself. Loss of the reservoir water and the resultant tailwater flooding, which included record flows as high as 23,000 cfs, profoundly influenced both the reservoir and river (Figure 3).
The small residue lake behind Fontenelle Dam was divided into littoral and pelagic zones following the draw-down and a limited sampling program initiated
(Figure 4). Information was collected on plankton, bottom fauna, water chemistry, and the fishery.
Plankton was collected from Fontenelle Reservoir using a Wisconsin closing plankton net. Samples were preserved and later sorted in the laboratory. Hauls were made from 10 to 0 feet, 30 to 10 feet, and 60 to 30 feet on a seasonal schedule.
-6- Bottom fauna samples were taken from Fontenelle Reservoir with an Eckman
dredge and from the Green River with a Surber square foot sampler. Sugar
floatation was used for initial field sorting; samples were then preserved and
subsequently processed in the laboratory. Taxonomic identification was made
within practical limits. Samples were taken from the river and reservoir as
often as the time schedule permitted. River bottom samples were taken at the
same locations used in past studies (Binns 1965 and 1967). Three square-foot
samples were usually taken at each sampling location.
Physical and chemical tests made on Fontenelle Reservoir and its tailwater
included: total alkalinity, total hardness, pH, electrical conductivity, turbidity,
and temperature. On the reservoir additional tests included dissolved oxygen,
hydrogen sulfide, carbon dioxide, and secchi-disc visibility. All determinations were made by standard methods. Carbon dioxide was determined by nomograph.
Samples were collected seasonally or more often when possible.
All fish samples from the reservoir were taken by use of experimental,
diving gill nets with bar mesh size ranging from 3/4 inch to 3 inches. Most
of the fish samples from the river were collected with dynamite. Some fish were obtained by electro-fishing. Reservoir fish samples were usually collected
in the spring, summer and fall. Most of the river samples were taken in the
fall.
The majority of fish tagged and released were hatchery rainbow trout. A
few rainbow trout were caught on hook and line, tagged, and returned to the river. Carp were usually caught by 21/2 and 3 inch gill nets, tagged with opercle
tags, and released back into the reservoir. Jaw tags, Peterson tags, and plastic
dart tags were used on trout.
A regularly scheduled creel census was conducted on the river in 1966. The
-7- river was divided into two areas: from Green River city to Big Island Bridge, and from Big Island Bridge to Fontenelle Dam. Each area was checked several times per month from May through September. Additional fishermen counts were made by airplane in both areas.
-8- RESULTS
Fontenelle Reservoir
Chemical and Physical
Salient results of the chemical and physical samples are presented below; more detailed information is tabulated in Appendix 1.
Temperature
Fontenelle Reservoir remained relatively homothermic throughout the
study period. No evidence of thermal stratification was found in the newly
filled reservoir when sampled in August 1965. Temperatures were 61.5°F at
the surface and 59.5°F at 54 feet, the maximum depth found at the mid-reservoir
sampling site.
U.S.G.S. temperature records for the Green River immediately upstream from the reservoir ranged from 550F to 650F in the week preceding the reservoir thermal sampling. Fontenelle Reservoir temperatures were very similar to the
Green River inflow and there is very little evidence to indicate the presence of a thermal current from the Green River, such as has been reported from other
Colorado River Drainage reservoirs (Stone and Miller, 1965; Eiserman et al, 1966).
After the September 1965 evacuation of water from the reservoir, temperatures varied only seasonally and very little depth-wise. During both winters of study the reservoir water was a uniform 33°F, and eventually formed an ice-cover of
° about 21/2 feet in thickness. Temperatures in the spring ranged from 45.5 F to
47°F and decreased slightly with increasing depth. A surface temperature of
72°F was recorded in late July, 1966. Early November temperatures were usually about 40°F (42-430F in 1965, 38-39°F in 1966).
Dissolved Oxygen
Prior to draw-down, oxygen was present in adequate amounts above the 30
-9- Appendix 1. Fontenelle Reservoir Water Chemistry from August, 1965 through May, 1967
Total Total Temp. Date Depth D.O. Alkalinity pH CO Hardness Cond. Turb. °F 2
8-26-65 0 7 120 8.0 2.5 154 280 10 61.5 10 7 137 8.0 2.8 154 280 12 61.5 20 7 120 7.75 4.5 137 284 12 61.5 30 6 137 7.25 15 137 284 12 61.0 40 3 137 7.25 15 154 304 12 60.5 50 1 137 7.25 15 154 338 8 59.5 54* Ll 137 7.5 15 171 345 78** 59.0
11-2-65 5 10 154 8.25 2 222 L25 42 15* 10 154 8.25 2 222 <25 42
2-22-66 0 9 154 7.35 14 222 530 6 33 10 8 154 7.35 14 222 539 9 20* 8 154 7.35 14 222 547 6
4-29-66 0 10 188 8.75 1 222 - 8 46.5 15* 10 188 8.75 1 222 - 6 45.5
7-66 0 72.0
8-66 154***
11-17-66 0 10 154 8.5 4.1 188 L-25 38.0 15 10 154 8.5 4-1 188 z_25 39.5 30 10 154 8.5 4-1 188 425 39.5 45* 10 154 8.5 4.1 188 425 39.5
2-21-67 0 9 171 7.5 11 205 410 33 10 10 171 7.5 11 205 /-10 30* 8 188** 8.0 3.8 240** 4:-.10 35
5-9-67 0 10 171 8.25 2 274 25 47.0 10 10 171 8.25 2 274 25 47.0 I 25* 10 171 8.25 2 274 30 47.5
at or very near bottom ** some bottom sediment picked up in sample *** from tailrace readings foot level. A sharp drop in oxygen concentration was noticed below this depth. (Figure 5). Water below the 50 foot mark approached an anaerobic condition, i.e., one ppm or less of oxygen. Following draw-down, dissolved oxygen was present at near saturation levels for the remainder of the study
(Figure 6).
Carbon Dioxide
Carbon dioxide remained well below critical levels at all times during the investigation (Figure 6). Samples taken in late August, 1965, showed a sharp increase in CO2 from 4.5 to 15 ppm, at about the 25 foot depth
(Figure 5). The 15 ppm CO2 found at this time was the highest level recorded during the study. After draw-down, carbon dioxide levels were below 2 ppm at all times except during late winter when between 10 and
14 ppm were present.
Alkalinity
Since the waters of the Green River drainage normally contain little or no carbonate, bicarbonates probably form the bulk of the alkalinity found in the reservoir and its tailrace. The reservoir bicarbonate concentration formed an erratic pattern above 30 feet prior to draw-down (Figure 5). A shift from
137 to 120 ppm and back to 137 ppm may have been due to inflow from the Green
River. U.S.G.S. records from the Green River station near LaBarge show a bicarbonate level of about 124 ppm CaCO3 during August, 1965. Bicarbonate concentrations in the reservoir, after evacuation, show a relatively uniform graphic pattern (Figure 6). Bicarbonate levels were lowest in late fall and early winter with a level of 154 ppm. An exception was noted in February of
1967 when a level of 171 ppm was found. Bicarbonate concentrations usually reached their peak during the spring. Dilution from the run off decreased
-10- the concentrations in the summer to a level of 154 ppm CaCO . 3 Hydrogen Ion
Hydrogen ion (pH) determinations made in August, 1965, showed a sharp shift toward neutrality with increasing depth (Figure 5). A slight reversal towards an alkaline level occurred at the bottom but this may have been due to bottom sediments picked up in the sample. The pH shift below 10 feet may have been caused by inflow from the Green River, but is more probably a function of high CO2 levels in the deeper waters.
Following evacuation of the reservoir, the pH assumed a pattern of changes identical to that exhibited by the river above (Figure 6). In general, the pH increased from a low winter level to a peak level in the spring. The spring peak was followed by a gradual decline through the summer and fall to the low winter level, thus completing the cycle. The spring peak was characterized by readings of around 8.75; the low winter level was near 7.35.
Total Hardness
Prior to drainage of the reservoir, total hardness determinations indicated that there was a layer of softer water between 10 and 40 feet
(Figure 5). The Green River inflow is a probable cause of this layering.
Total hardness, during this period, ranged from 137 to 171 ppm. Again, the high value of 171 ppm, taken near the bottom, may have been due to bottom sediment in the sample.
After evacuation, total hardness samples showed uniform concentrations with respect to depth, but with some seasonal fluctuation (Figure 6). The low occurred in the fall of 1966 when a concentration of 188 ppm was recorded.
The peak reading of 274 ppm was in the spring of 1967. Turbidity
Turbidity maintained a low level through the study. This component was seldom greater than 25 ppm. The highest readings usually occurred during the spring run off, when the lake assumed a muddy color. Turbidity level at this time was about 25-30 ppm. Color of the reservoir water, at other times, was usually due to biological conditions rather than silt.
Electrical Conductivity
Only a few conductivity measurements were made on the reservoir water.
A reading of 547 micromhos was recorded in the winter of 1966-67. Conductivity checks made prior to draw-down in 1965 showed a steady increase in conductivity with increasing depth. The range was from 280 micromhos at the surface to
345 micromhos near the bottom.
Bottom Fauna
Bottom samples were collected in Fontenelle Reservoir only after evacuation.
The first samples were taken in November, 1965. (Appendix 2). The bottom fauna of the reservoir was found to be relatively uniform in species variety. Most of the benthic faunal variation was seasonal. Members of the midge family,
Tendipedidae, were dominant in the benthos, and especially numerous in the littoral zone. The tendipeds decreased markedly with increased depth. For example, in November, 1966, midge numbers decreased from 526 organisms per square foot, in 5 feet, to a level of 116 organisms per square foot, at the
35 foot depth.
Annelid worms, mostly Tubificidae, were also commonly found in the bottom samples. This group was most abundant in the deeper water. Other organisms found in the bottom samples were scuds (Gammarus sp.) and nematode worms. Both groups occurred only sporadically in the samples, but the scuds are believed to
-12- Appendix 2 Numbers and Kinds of Organisms taken in Eckman Dredge Samples at Fontenelle Reservoir, 1965 and 1966
Upper Lake Lower Lake
Date 5-19-66 11-2-66 11-3-65 5-20-66 11-1-66
Organism Depth (ft.) 2.5 15 5 17 20 2.5 5 19 30 5 10 35
Tendipedidae 258 24 2,308 420 66 54 66 30 20 526 868 116
Tubificidae 62 186 6 12 2 314
Other Oligochaeta 12 2
Nematoda 4 2 4
Gamma rus 18 2
Total No. per sq. ft. 262 24 2,328 482 252 72 68 30 32 530 872 430
Volume per sq. ft. 1.4 1.2 4.8 3.6 2.2 0.8 1.2 0.4 0.6 0.8 -- 6.0
-12A- be more common than the sampling method showed.
The littoral zone of the inflow and of the reservoir was found to be
the most productive. A littoral zone population of 2,328 organisms per
square foot, with a centrifuged volume of 4.8 cc, was taken in November,
1966. This is by comparison to a littoral zone population of 530 organisms
per square foot and a volume of 0.8 cc in the lower end. On the same date
the profundal zone of the lower end had a larger biomass than the littoral
areas. This is probably due to the fact that midges from the profundal
zone were larger than their counterparts in the littoral area.
Production of reservoir bottom organisms ranged from 30 to 2,328 per
square foot; the volume range was 0.4 to 6.0 cc per square foot.
Plankton
Results of the plankton sampling program are tablulated in Appendix 3.
Zoo-plankton was identified to order and phyto-plankton to genus.
Cladocera, Copepoda, Rotatoria and Ostracoda were represented in the
plankton samples. The cladocerans were common in summer and rare at other
seasons. Adult copepods were sporadic in occurrence. The nauplii of this
group were found at all seasons until the fall of 1966 when they disappeared
from the samples. Members of the Rotatoria were present in the summer of
1965. The rotifers reappeared and became very abundant in the summer of
1966; this group persisted into the fall and winter, but were not found in
the 1967 spring samples. The Ostracoda were found only below 30 feet in the
summer of 1965. A total of 18 genera made up the phyto-plankton of Fontenelle
Reservoir. Mougeotia, Fragillaria, Tabellaria, Asterionella, Sphaerocystis,
and Navicula were important at various times during the study. Spirogyra was
noticeable on littoral zone plants in the late summer of 1966.
-13- Appendix 3. Number of Plankters taken in Plankton Samples at Fontenelle Reservoir from August 1965 to May 1967
Date ...,„ -. ------.....-ww w-„-vy 44 Lf vy ,-...... 04, Location J. Y-0 / Middle Rea. Lower Res,. Lover Res. Gover Res, Lover Res. Upper Res. 1/ Lover Res. Lower Res. Lower Res. Lower Res. Depth (feet) 0-10 10-30 0-10 10-20 0-10 10-30 30-60 0-10 10-20 ' 0-10 10-15 0-10 ' 0-5 0-10 10-30 30-40 0-10 10-30 30-45 0-10 10-30 0-10 10-20
Cladocera 29 9.5 4.7 17 12 24 15.5 3.0 2 1.2 1.0 copepoda 6.0 1,4 1.8 1 2 1.5 1.0 1 2.0 1 Copepods Nauplil 25 10.5 8.3 3 0.6 1 13 4 5 2 10 8 2 5.5 4.0 Rotatoria 3 4.0 1.7 865 55 48.8 13.9 11 7.5 6.7 270.0 8.0 Ostracoda 0.3 Volvos 236 75.5 6.3 2 1 2.5 1 0-7 Sphaerocystis 22 30.5 6.7 34 275 87.5 60.0 3 Pediastrum 1 0.5 knkistrodesmus 1 15 2 14 Planktosphaeria 12.5 4.7 17 85 112.5 20 8.8 116.7 Xcrinastrum 1 2.0 Mougeotia 1,152 549.5 149.3 115 13.9 5.1 1 6 6 3 8.5 10.0 Spirogyra 2 2 6 4 1 2.6 2.5 2 Closterium 1.0 0.7 1 1 1 1 0.5 5 Ceratium 9 4.4 3 1 Sonora 1 0.5 0.3 20.0 Asterionells Formosa 15 3 27 2 23 10 2.6 310 27.5 26,7 97.5 5.0 105.0 ksterionella Gracillims 5 6.1 3 10 4 4 10 45 25.8 11.9 160 80.0 64.0 17.5 5 iynedra 8 13.3 Fragillaria 1 174 59 174 28 o 815 305 112.0 1,017.0 128 24.0 64.0 2.5 25.0 30 rabellaria 34 3 96 4 47.5 342.5 54.0 330 lavicula 23 2 40 6 4 25 5.0 365.0 65 lnacystis 3 1.5 1.3 knabaena 'inidentified Pyrrophyta 1 Inidentified Desmidiaceae 5 Inidentified Bacillariophycese 1
1,507 730.5 total Organisms 185.7 137 25.0 10.1 2 282 74 361 46 66 2793 798 325.0 1..110.8 666 152.8 293.4 457.5 368.0 554.5 431
total Number of Groups 13 13 4 4 12 8 2 11 7 9 6 6 12 11 13 7 11 6 8 5 5 7 5
1/ Littoral zone, all other samples from Pelagic areas
-13A- Some seasonal changes in the plankton population of the upper 10 feet
of water was noticed during the study (Figure 7). The total plankton
population was greatest in the summer (798 per liter) and lowest in the
winter (10.1 per liter). Zoo-plankton reached its peak during the winter
of 1966-67 when 270 organisms per liter were taken. ThezooTlankton was
relatively sparse throughout the study period. The rotifer bloom noted
above was the only exception.
The vertical distribution of the Fontenelle Reservoir plankton
population for August, 1965 and 1966, is shown by Figure 8. In August,
1965, the bulk of the plankton population was at or near the lake surface.
The dominant phyto-plankton was an algae tentatively identified as Mougeotia.
Much of the Mougeotia was floating in clumps on the surface. Cladocerans were the dominant zooplankton. The plankton population gradually tapered off, with increasing depth, from a level of 1,500 plankters per liter in the upper 10 feet, to 186 plankters per liter in the lower 30 feet. The number of taxonomic groups showed only a slight decrease with increased depth. In other words, plankton species composition was uniform relative to depth, but total numbers decreased.
In August, 1966, plankton habitat was greatly reduced by draw down.
The maximum depth at this time was about 40 feet, as compared to 125 feet in August, 1965. The vertical distribution and composition of the plankton was different in August, 1966, from that of the previous year. In 1966 most of the plankton (1,110 per liter) was found in the lowest 10 feet of the reservoir. A zone of relatively sparse plankton (325 per liter) was found in the mid depths, while in the uppermost 10 feet plankters numbered 798,per liter.
-14- The dominant phyto-plankton was the diatom, Fragillaria; the dominant zoo-plankters, Cladocera. Surprisingly, the largest number of taxonomic groups
was found at the depth containing the least number of plankters. Conversely,
the smallest number of taxonomic groups was located near the bottom where the
number of plankters was greatest.
After draw-down, the plankton population of the entire residual pool
appeared to be quite homogenous.
Fishery
Gill net sampling of the fish population was initiated on a limited exploratory basis in August, 1965. Netting was continued after that date on a seasonal basis, except in the winter. The most intensive work was done in the summer of 1966. Much of the sampling was characterized by a high effort per unit of catch.
The mean catch per net-hour of all fish was 0.94 in FY 1966 and 1.35 in FY 1967. Part of the increase may be due to increased effort and part to increased numbers of fish. However, the data presented below is believed to be indicative of the reservoir fish population. The data was processed on a fiscal year basis (July 1 to June 30) to follow the investigational organization.
Composition, Abundance, and Distribution
The following species were taken in Fontenelle Reservoir gill net sets: rainbow trout (Salmo gairdneri Richardson), brown trout (Salmo trutta Linnaeus), whitefish /1Prospium williamsoni (Girard)J, carp (Cyprimis carpio Linnaeus), flannelmouth sucker (Catostomus latipinnis Baird and Girard), bluehead sucker
Pantosteus sp., Utah chub /Gila atraria (Girard)], bonytail chub (Gila robusta
-15- Baird and Girard) and a hybrid with apparent lake trout characteristics.
Fathead minnows (Pimephales promelas Rafinesque) and redside shiners
TRichardsonius balteatus (Richardson)] were collected with dynamite.
Comparison of the reservoir species composition, as indicated in gill net catches for the FY 1966 and 1967, reveals several differences
(Figure 9). In both years, flannelmouth suckers were the dominant fish in the reservoir; their relative position in the population increased only slightly during the study. Rainbow trout were the ranking subdominant.
This fish comprised 29% of the population in FY 1966, but only 22% in FY
1967. Brown trout (15%) and whitefish (8%) were the only other species caught in the FY 1966 netting. In FY 1967, four other species appeared in the nets and the population composition was changed. Flannelmouth suckers, rainbow trout, carp, bonytail, brown trout, Pantosteus suckers,
Utah chub, and whitefish were found, in that order. Trout comprised
25 percent of the total fish population; flannelmouth suckers, 50 percent.
Thus, the percentage of trout in the total population decreased from FY
1966 to FY 1967 (44% to 25%).
RAINBOW TROUT
The length frequency distribution of the reservoir rainbow trout changed during the investigational period (Figure 10). In FY 1966, most of the fish taken were in the length range 375 mm (14.5 in.) to 475 mm
(18.5 in.). The average length and weight for that period was 434 mm
(17 in.) and 842 grams (1.8 lb.). In FY 1967, the rainbow trout taken varied considerably in size. However, most of the fish were in smaller size ranges. The numbers of larger fish appeared to be reduced during the latter stages of the study. An average length and weight of 362 mm
-16- (14.25 in.) and 664 grams (1.5 lb.) was recorded for the FY 1967 rainbow
trout. Length change, over the two years, represents a decrease in average
length of 72 mm (3 in.). This change appears to be due to: (1) a reduction
in numbers of larger fish from fishing and other mortality, and (2) the
entrance into the fishery of sub-adults just attaining catchable size. The
gill net catch-rate of rainbow trout increased from 0.171 in FY 1966 to
0.354 in FY 1967, perhaps because of increased fishing effort in the latter
period.
Reservoir rainbow trout reached a length of 300 mm (6 in.) in 2 years;
subsequently, this relatively rapid growth rate decreased (Figure 11). Average
length at five years was found to be 464 mm (18.25 in.). The oldest rainbow
trout netted was six years. The decrease in average length between ages five
and six is probably due to small sample size. Two year olds were most numerous
in the nets, however, age groups three, four and five were not uncommon. Gill net captures of one and six year rainbow were rare.
Average condition factors in FY 1966 and FY 1967 were 1.17 and 1.24 respectively (Appendix 4). In FY 1966, condition factors (K) for specimen
lengths of 315 mm, 415 mm and 495 mm were 1.50, 1.21, and 1.03. Comparable
lengths in FY 1967 had "K" factors of 1.30, 1.26 and 0.96. Average "K" factor data indicate an improvement in condition of rainbow trout; individual
length group condition factors suggest a slight condition decline which may
be normal decrease due to age.
BROWN TROUT
Brown trout, which were found in limited numbers, are from populations
present prior to impoundment. This trout, an important component of the
fishery, apparently has become fairly well established, but is not numerous
-17- Appendix 4 Condition Factors of Four Fish Species in Fontenelle Reservoir 1965 to 1967
Condition Factor
Total Rainbow Trout Brown Trout Carp Flannelmouth Sucker Length (mm) 1966 1967 1966 1967 Aug. 1966 August 1966
175 1.21 185 1.02 195 205 1.62 215 1.11 1.26 225 1.40 1.86 235 1.35 1.12 245 1.29 1.28 255 1.50 265 1.51 1.97 1.29 275 1.45 0.96 1.10 1.99 1.19 285 1.21 1.22 295 1.41 1.18 305 1.20 1.20 315 1.50 1.30 1.20 1.11 325 1.34 1.21 0.87 1.18 335 1.41 1.28 0.94 1.28 345 1.50 0.91 1.20 355 1.18 1.09 1.18 365 1.34 1.34 1.15 1.09 375 1.32 1.18 1.19 1.27 1.84 1.04 385 1.19 1.02 0.98 1.91 0.94 395 1.20 1.16 1.04 1.14 405 1.25 1.11 1.13 415 1.21 1.26 0.90 425 1.02 1.16 435 1.14 1.06 2.62 445 1.08 1.16 2.02 455 0.65 1.15 1.17 2.22 465 1.11 1.06 1.92 475 1.12 2.06 485 1.16 1.08 2.04 495 1.03 0.96 1.06 1.77 505 0.98 1.87 515 0.99 1.95 525 1.05 1.94 535 545 555 1.72 565 1.01
-17A- by comparison to rainbow trout.
In spite of increased netting efforts net catch-per-hour of brown trout
declined from a rate of 0.16 in FY 1966 to 0.035 in FY 1967. These data
suggest that the reservoir brown trout population has been reduced by
emigration and/or fishing pressure, but are insufficient to indicate which.
Gill netting efforts in FY 1966 indicated that brown trout taken were
relatively limited in size. Most of the 13 brown trout taken were in the
325-395 mm (12.8-15.6 in.) size range. In contrast, the FY 1967 gill net
catch included brown trout (7) with a much greater variation in length
/315-515 mm (12.4-20.3 in.)/. Average length in FY 1966 was 354 mm (14.9
in.) compared to 414 mm (16.3 in.) in FY 1967. Average weights for brown
trout in FY 1966 and FY 1967 were 459 grams (1 lb.) and 778 grams (1.7 lb.),
respectively.
Comparison of average condition factors for brown trout showed a slight
upward trend during the study period (Appendix 4). The mean "K" factor for
FY 1966 was 1.021 and for FY 1967, 1.085.
Analysis of all scales and otoliths taken during the study indicate that
it takes brown trout seven years to attain a length of about 500 mm (20 in.),
(Figure 11). No age I or VI brown trout were caught in the gill nets. Lengths
at ages II, III, IV and V were 327 mm (12.9 in.), 352 mm (13.0 in.), 388 mm
(15.3 in.) and 408 mm (16.1 in.), respectively. Most of the brown trout
population is evidently made up of three and four year olds. Only a few
individuals older than four years were found; these were probably immigrants
from areas not treated in 1962. The brown trout population appears to be
still in the process of re-establishing its pre-treatment age structure.
WHITEFISH
Whitefish were uncommon in the reservoir during the study period. This
fish was apparently most numerous when the reservoir was first filled. Although -18- no whitefish were taken in gill nets set in August, 1965, a large number was_ seen feeding near the reservoir spillway. Apparently some of these were swept, or swam, over the spillway as dead or dying whitefish were often found for several miles downstream. This mortality may have resulted from attempts to move through or out of the reservoir, Net catch rates dropped sharply throughout the investigation, indicating that the white- fish were unable or unwilling to adapt to the lentic environment. The net catch per hour in FY 1966 was 0.086 and in FY 1967, 0.008. Whitefish were usually caught in the fall and spring net sets, suggesting the probabil- ity of some unsuitable factor, perhaps temperature, in the summer.
The mean lengths and weights of whitefish increased from FY 1966 to FY
1967. The mean lengths and weights for 1966 were 238 mm (9.4 in.) and 124 gms (0.25 lb.) and for 1967, 306 han (12 in.) and 325 gms (0.7 lb.). Apparently, only a small number of larger whitefish were utilizing Fontenelle Reservoir at the conclusion of study in 1967.
Attempts to age whitefish by scale analyses were unsuccessful because of irregular growth patterns.
FLANNELMOUTH SUCKER
As already noted, the flannelmouth sucker was the most common fish caught in the gill nets. An increase in catch numbers and rate per hour of netting was noted throughout the study. Catch per net hour was 0.524 in FY 1966 and
0.634 in FY 1967.
A change was also evident in mean lengths and weights which increased from 240 mm (9.4 in.) and 149 gms (0.3 lbs.) in FY 1966 to 304 mm (12 in.) and 289 gms (0.6 lb.) in FY 1967
-19- Most of the suckers in the August, 1966, samples were about 305 mm
(12 in.). Attempts to age suckers were unsuccessful, but it is suspected that the age group represented by the 305 mm peak is the 1965 year class; in other words, offspring of a mature population remnant in the briefly filled reservoir.
Data from August, 1966, net catches indicated that flannelmouth sucker condition factors averaged 1.164 and ranged from 0.938 to 1.290
(Appendix 4).
CARP
No carp were caught or seen in Fontenelle Reservoir in FY 1966, probably because of the limited, exploratory nature of the netting program.
Aerial checks of the reservoir first established the presence of carp in some of the littoral areas. Only a few carp were captured in the standard experimental gill net sets in July,1966. Subsequently, a switch was made to large mesh gill nets (21/2 to 3 in.) deliberately set in the "carp areas" located by airplane. Standard experimental nets were set simultaneously.
Carp up to 7 pounds were found to be surprisingly common on the shoals at the head of the reservoir. About 50 carp were tagged and released. None of the tags had been recovered at the conclusion of the study. The mean length and weight of the carp were 414 mm (16.3 in.) and 1,744 gms (3.9 lb.).
The data indicated that several age groups were present in the carp popula- tion and that most of the carp present were from the larger size groups.
Carp condition factors ranged from 1.724 to 2.618 with a mean of 1.971
(Appendix 4).
BONYTAIL CHUB
No specimens of bonytail were caught until the summer of 1966 when a
-20- few small specimens were taken. The average length of 23 bonytails netted in FY 1967 was 212 mm (8.3 in.); the average weight of 8 specimens was 157 gms (0.3 lb.). The largest bonytail taken was 305 mm (12 in.) and weighed
300 gms (0.7 lb.). None were mature.
UTAH CHUB
Three Utah chubs were found in the gill net sets made in July and
August, 1966. This fish is believed to have been brought in by bait fishermen as none were known to be in the river above Fontenelle Dam prior to dam closure. Their mean length and weight was 159 mm (6.2 in.) and 82 gms (0.25 lb.). This species has not been caught since the initial appearance.
BLUEHEAD SUCKER
Bluehead suckers occurred occasionally in the gill net catches in
FY 1967; none were taken in FY 1966. The mean length and weight of this species was 209 mm (8.2 in.) and 101 gms (0.2 lb.).
FORAGE FISH
Forage fish were observed to be common in the small bays along the shoreline. Blasting indicated that most of these were young fathead minnows, with a few young flannelmouth suckers, redside shiners, and dace. Flannelmouth sucker young were numerous in some areas.
Harvest
No creel census data were collected from Fontenelle Reservoir during this investigation.
Food Habits
A total of 50 rainbow trout and 20 brown trout stomachs were checked
-21- for food content during the study (Table 2). Because of unexpected complications and delay in data processing, no attempt was made to calculate percent occurrence for the food items. All food habit data in this report are based on percent, by volume, of total number of stomachs sampled per trout species.
Organic debris was the primary (42%) food item in the rainbow trout stomachs. Organic debris includes all un-sortable and un-identif- ible plant and animal residues from stomach contents. Although field observations suggest that algae are an important component of organic debris, it is not necessarily true that a high percentage of organic debris means that the trout are primarily herbivorous. The principal animal component of the diet was midge larvae (Tendipedidae) (37%).
This food preference probably reflects the abundance of midges in
Fontenelle Reservoir. Microcrustaceans, adult beetles (Coleoptera), bugs (Hemiptera), snails (Mollusca) scuds (Amphipoda), and adult may- flies (Ephemeroptera) also occurred in the rainbow trout diet.
Organic debris was also the most common item in brown trout stomachs.
Relative to animal content the brown trout diet, by comparison to that of the rainbow, was more evenly divided among fewer items. In order of importance, scudqfish and midges made up the bulk of the animal diet component. Brown trout food habits were difficult to sample because of an apparent tendency for the fish to regurgitate when caught in a gill net.
-22- Table 2. Food Habits of 50 Rainbow Trout and 20 Brown Trout from Fontenelle Reservoir, 1965 and 1966
RAINBOW TROUT (1) BROWN TROUT (2) FOOD ITEM Volume (c.c) Percent Volume (c.c) Percent
inorganic debris 0.51 0.2 organic debris 123.36 41.6 9.53 34.4 undetermined fish 2.50 0.8 5.50 19.9 Mollusca 7.08 2.4 0.20 0.7 Cladocera and Copepoda 13.41 4.5 Ephemeroptera nymphs 0.01 Trichoptera larvae 0.01 Odonata nymphs 0.60 0.2 0.01 Coleoptera larvae 0.01 Hemiptera 8.96 3.0 Amphipoda 6.18 2.1 8.73 31.5 Diptera larvae 114.96 36.8 3.40 12.3 Diptera adult 0.02 0.1 0.30 1.1 Ephemeroptera 7.81 2.6 Coleoptera adult 11.00 3.7 Hymenoptera 0.01 Hirundinea 0.70 0.2
TOTALS 296.61 100.2 27.68 99.9
(1) Includes 2 empty (2) Includes 6 empty RESULTS
Green River
Section I
Relatively little information was collected in Section I because of
inaccessability and limited public usage. The five miles immediately
downstream from Green River City are fairly accessible and receive this
section's highest use, but compared to Sections II and III, fishing
activity is relatively light.
U. S. Geological Survey chemical and physical data from a station just
upstream from the upper boundary of Section I was not available when this
report was written. Project personnel collected most of the chemical and
physical data presented here.
Chemical and Physical
Chemical and physical data for Section I is tabulated in Appendix 5.
Bitter Creek is the principal tributary in this section and periodically contributes heavy silt and chemical loads to the Green River (Table 3).
Some pollution from Rock Springs also may enter the Green River from this
source.
Table 3. Bitter Creek Water Composition on March 21, 1966, during the Lowland Runoff (in m HARDNESS SO4 TURBIDITY HCO3 pH
Total Ca Mg 325 170 155 475 5,375 140 8.5 Appendix 5. Green River Water Chemistry in Sections I--IV from September 1965 to April 1967
Section I (at Kinkaid Ranch) Hardness Cond- Turb- Temp. Date Total Ca Mg HCO3 SO4 Fe Cl uctivity idity pH OF .
10-18-65 154 8.75 48 11-17-65 274 171 9.0 40 12-19-65 360 200 160 240 360 tr. 20 940 5 8.5 32 1-14-66 308 170 138 188 310 tr. 20 0 8.0 32 2-14-66 325 190 135 188 238 0.04 20 727 0 7.75 32 4-16-66 222 140 82 154 210 0.2 20 564 42 8.75 46 8-10-66 188 154 513 8.9 70 9-19-66 222 130 90 140 260 0.18 25 684 130 8.5 53 10-21-66 274 150 124 154 320 0.05 20 192 8.5 37 11-20-66 342 145 197 154 320 28 17 8.75 40 1-17-67 394 200 194 205 375 0.06 20 941 o=10 8.25 32 4-17-67 205 150 55 154 135 0.08 15 564 48 8.25 41
Section II (at Big Island) 10-18-65 154 8.5 52 11-17-65 274 171 8.75 40 12-18-65 342 180 162 222 300 0.15 20 770 7 8.0 32 2-15-66 274 180 94 188 225 0.05 15 701 0 7.75 32 4-16-66 205 140 65 154 190 0.22 15 564 46 8.75 47 8-10-66 188 120 496 8.8 72 9-14-66 240 130 110 120 240 0.03 ' 15 667 10 8.75 59 10-21-66 274 160 114 154 350 0.03 15 40 8.5 40 11-18-66 291 135 156 171 270 15 7 8.25 40 1-18-67 360 210 150 188 375 0.01 20 1,009 410 8.0 32 4-17-67 205 120 • 85 154 135 0.06 10 547 20 8.75 42
Section III (at CCC Bridge) 10-19-65 136 8.75 49 11-16-65 240 171 8.75 40 12-17-65 274 150 124 188 150 0.05 15 547 10 8.25 34 1-14-66 240 150 90 171 260 tr. 18 0 8.25 34 2-21-66 257 160 97 154 170 0.08 13 581 0 7.75 34 3-21-66 213 165 '48 162 130 32 8.25 -- 4-16-66 188 120 68 154 80 0.2 10 428 30 8.75 43 8-11-66 154 120 342 8.9 71 9-14-66 154 100 54 140 75 tr. 15 356 12 8.8 58 10-20-66 171 100 71 137 110 0 10 462 4_5 8.75 45 11-15-66 205 110 95 154 115 0 10 2 8.75 41 1-16-67 273 160 113 154 130 0.05 13 547 4..10 8.0 35 4-17-67 188 120 68 134 110 0.06 10 462 15 8.5 42
Section IV (at Names Hill) 9-23-65 151* 154 340* 8.25 47 10-19-65 154 8.5 49 11-16-65 205 171 8.75 39 12-17-65 205 188 445 8.0 32 2-18-66 205 171 428 7.25 32 4-27-66 205 188 8.75 45 8-11-66 137 120 291 8.8 70 9-14-66 154 90 64 140 68 0.18 10 342 180 8.25 54 10-19-66 188 120 68 154 85 0.05 25 462 10 8.5 42 11-20-66 223 100 123 154 87 6 2 8.25 40 1-18-67 240 150 90 154 63 tr. 5 428 4-10 7.8 32 4-18-67 240 130 110 188 85 0.09 10 428 38 8.75 49
* from USGS records
-24A- Turbidity
Turbidities recorded at the sampling station near the old Kinkaid
Ranch ranged from 0 to 192 ppm. Highest levels occurred in the fall of
1966; lowest readings were found in the winter. The stream was usually
muddy during the spring runoff and periodically during the summer and
fall due to water release patterns at Fontenelle Dam and occasional
rainfall runoff.
Hardness
Total hardness ranged from 188 ppm to 394 ppm CaCO3 during the study
period. The lowest concentrations occurred in the summer time. Hardness usually increased gradually through the fall and winter to a peak level just prior to spring runoff. Calcium hardness made up most of the total.
Both the calcium and magnesium portions of the total hardness followed the
seasonal pattern of peak winter levels and low spring summer concentrations,
but the calcium hardness seasonal pattern was not as clear cut as those for magnesium and total hardness. Calcium ranged from 130 to 200 ppm CaCO3 and magnesium from 82 to 197 ppm during the study.
Bicarbonate
As with hardness, concentrations of bicarbonate were highest in the winter (205-240 ppm CaCO3). The lowest bicarbonate concentration found was
140 ppm CaCO3. In general, the bicarbonate concentration of the Green River in Section I was 170 ppm CaCO3, a higher level than most U. S. waters (McKee and Wolf, 1963).
Sulfate
Sulfate levels also followed the pattern of the high winter-low spring concentrations. The range of sulfate was 135 ppm (April, 1967) to 375 ppm
-25- (January, 1967). A low of 65 ppm was reported by the U.S.G.S. (U. S.
Geological Survey, 1965) for the first part of July at Green River City.
Even at its lowest concentration the river sulfate level is well above levels usually found in the United States. The concentrations commonly found in the river are near or over levels considered detrimental for irrigation water and approach the maximum for good domestic and stock water
(McKee and Wolf, 1963).
Chloride
The chloride content of the Green River, in Section I, was relatively low and well within permissible levels. River concentrations were usually about 20 ppm. A drop to 15 ppm was noted in April, 1967, and the highest levels, 28 ppm, occurred in the fall of 1966.
Electrical Conductivity
The foregoing data imply high concentrations of dissolved minerals in this section of the Green River. Conductance values recorded during the investigation corroborate the presence of high mineral content. The minimum conductance found for this section was 513 micromhos and the maximum
941 micromhos. The mean conductance was 705 micromhos. Specific conductance was lowest in the summer and highest during the winter. The above conductance values are well below the upper limit for good fish streams; the values recorded are about what one would expect of a typical, alkaline, western stream (McKee and Wolf, 1963).
Hydrogen Ion
Hydrogen ion values found in this section were always alkaline. The river pH in Section I demonstrated a seasonal trend that was not well enough defined to qualify as a cycle. Apparently, pH was more dependent upon other factors,
-26- such as stream flow and climatic conditions. The lowest pH usually occurred
in the winter just prior to thaw (7.75 in 1966), after which, the pH usually
returned to a more alkaline level. Highest hydrogen ion readings were generally
found in the fall prior to freeze-up, but a value of 8.9 was recorded in August,
1966.
Temperature
The only temperature data obtained during the investigation were from occasional spot checks with a pocket thermometer. The maximum water temperature recorded for Section I was 74°F in early August, 1966; previous experience suggests that this value was probably close to the true yearly maximum. The under-ice temperature during the winter months was usually 32°F.
Bottom Fauna
The bottom fauna of the Green River has been sampled and reported upon by Bosley (1960) and Binns (1965). The basic data obtained during the present investigation are tabulated in Appendix 6.
A low numerical and volumetric level of benthic invertebrates was present in Section I during the fall of 1965 (Figure 12). Less than 100 organisms per square foot were present until after the spring runoff in June, 1966.
The benthic population reached a numerical peak in October, 1966 of almost
350 organisms per square foot; after which, numbers of organisms decreased.
Volumetric samples of aquatic invertebrates generally followed a similar pattern of increase and decrease.
Benthic invertebrates were much more abundant in FY 1967 than in FY 1966.
Records also showed that the population level, in Section I, was higher during the fall of 1964 than at the same time in 1965. The record flood in September,
1965, apparently reduced the bottom invertebrate population through damage to
-27- Appendix 6 Average Number of Organisms per Square Foot taken in Bottom Samples at Station 1 from October 1965 to April 1967
1965 1966 1967
No. Samples 3 3 3 3 3 3 3 3 1 3 2 1
Hydracarina 0.3 Tubificidae 2.3 1.0 0.3 4.3 1.0 1.3 3.0 1.0 Other Oligochaeta 0.3 28.5 Tendipedidae 7.0 40.0 5.3 59.0 21.3 2.0 141.7 192.3 172.0 141.7 113.5 33.0 Simulidae 1.3 4.7 1.0 Tipulidae 0.3 0.5 Heleidae 0.3 Rhagionidae 2.0 Baetis 1.0 1.7 1.7 10.7 2.3 1.0 31.7 13.0 1.0 8.0 9.0 Tricorythodes 0.3 0.3 0.7 1.3 10.3 71.0 0.3 22.5 6.0 Ephemerella 2.0 1.3 1.0 7.0 2.0 6.7 9.0 1.7 2.5 4.0 Paraleptophlebia 0.1 Rhithrogena 6.7 16.7 17.7 17.3 4.0 0.7 0.3 0.5 Heptagenia 0.3 0.3 5.0 21.0 0.5 Ephoron 3.0 Perlidae 0.7 0.7 2.3 3.0 Perlodidae 0.7 1.0 0.3 0.7 1.7 1.0 Hydropsychidae 0.3 0.3 1.3 24.0 41.0 10.0 0.5 Hydroptilidae 1.7 1.0 Leptoceridae 0.7 15.0 0.5 Rhyacophilidae 18.0 11.0 0.5 Elmidae 1.3 1.0 Gomphidae 1.7 2.7 1.0 Pyralididae 0.3
Average Total No. 21.9 62.0 26.6 95.4 31.3 13.1 152.6 296.3 347.0 168.2 181.0 58.0
Average Total CC 0.1 0.3 0.2 0.4 0.5 0.1 0.6 1.8 2.4 0.7 0.4 1.0
No. Taxonomic groups 10 6 7 6 5 7 11 12 11 11 , 12 8 habitat and decimation of organisms.
The midges, Tendipedidae, were dominant throughout FY 1967 (Figure 13).
The group made up at least 507 of the invertebrate population at all times.
In FY 1966, dominance fluctuated between several taxonomic groups. Tendipedidae
(midges), Rhithorogenia (mayflies), and Ephemerella (mayflies) each were dominant at various times. This may be an indication of flood damage to the benthic population. An unusual appearance of significant numbers of Tubificid worms in October, 1965, may also be indicative of a change in population structure.
There was no evidence of a shortage of fish food organisms in Section 1 after July, 1966.
Fishery
Only a limited number of fish were obtained from Section I during the study period. Sampling was limited during FY 1966 but more frequent in
FY 1967. The fish population in Section I appeared to be much reduced from that found prior to the 1965 flood. Part of the decrease in trout numbers may be related to a cut back in the stocking program, but the flood probably pushed many of the trout (and other species) downstream into the Flaming
Gorge Reservoir.
The average length and weight of five rainbow trout sampled was 387 mm
(15.2 in.) and 667 gms (1.5 lb.). All rainbow were taken in the fall of 1966; none in 1965. The only other species of fish taken in Section I was the flannelmouth sucker. A number of this species was killed at one deep hole in October, 1965, but only a few were found during the 1966 fall sampling.
The mean lengths and weights of the latter sucker group are 392 mm (15.4 in.) and 552 gms (1.2 lb.)
-28- Section II
Section II, including the Green River City area, is more popular with
fishermen than Section I. Most of the fisherman-use in Section II is centered
in two areas: Green River City and the Big Island Bridge-Stauffer stretch.
The river, in the Big Island area, appears to be better trout habitat.
Chemical and Physical
Much of the alkaline material entering the Green River below Fontenelle
Dam comes into the river in Section II. Alkali Creek and the Big Sandy River
are the only permanent tributaries in Section II. Alkali Creek was found to
contain considerable amounts of dissolved minerals (Table 4). However, this
tributary is relatively small (1-3 cfs) and apparently spring fed. The data
indicates that the creek is well named.
Table 4. Alkali Creek Chemical Composition Hardness DATE Total Ca Mg SO4 Turbidity Fe HCO3 pH
9-26-65 924 100 824 2,750 5 tr. 685 8.25
3-21-66 906 290 616 2,500 37 616 8.75
The Big Sandy River enters the Green River at the upper end of Section II
and is, at best, a disposal ditch for irrigation return flows from the Farson
farming area. Water from this tributary is highly mineralized and undoubtedly
exerts a major influence on the chemical composition of the Green River. A
comparison of spring and fall water composition indicates that the chemical
load remains high year around (Table 5). It is interesting to note that the
Big Sandy River chemical load is drastically reduced upstream from the Farson
area. This tributary presents a good example of what can be expected in this region in streams influenced by irrigation return flows.
-29- Table 5. Chemical Composition of the Big Sandy River
(A) 9-6-62* (B) 9-6-62* 3-21-66
Hardness (ppm) Total 19 955 735 Ca 450 Mg 285
SO4 (ppm) 3 1,360 1,300
Conductivity (micromhos) 51 2,920
HCO3 (ppm) 26 233 188
pH 6.7 7.5 8.25
Turbidity (ppm) 42
Dischg. (cfs) 24 29
Dissolved Solids (ppm) 36 2,430
A. Above Farson B. Below Farson * Data from USGS records
The chemical composition of the Green River in Section II is also
influenced seasonally by contributions from numerous intermittent creeks.
These creeks usually contain water only during the lowland run-off in the
spring and often are important sources of silt for the Green River. A
chemical check was made on Dry Creek, a typical intermittent tributary,
in March, 1966, to determine the chemical contribution of the intermittent
tributaries to the main river (Table 6). A high turbidity of 5,875 ppm was found.
Table 6. Chemical Composition of Dry Creek on March 21, 1966 (in ppm) Hardness Total Ca Mg SO4 Turbidity HCO3 pH
51 20 31 160 5,875 103 8.6
-30- Physical and chemical determinations for the Green River proper in
Section 11 were made at Big Island Bridge. The data are tabulated in
Appendix 5.
Turbidity
The turbidity in Section II was usually less than ten ppm during the investigation period. The highest turbidity recorded was 46 ppm on April
16, 1966. Highest records were usually during the spring run-off and after heavy rains.
Hardness
Total hardness values fluctuated between 188 and 360 ppm CaCO3. Calcium provided most of the hardness, except in the winter or late fall when magnesium readings approached or exceeded calcium levels. Calcium hardness ranged from
130 to 210 ppm CaCO3; magnesium hardness from 65 to 162 ppm CaCO3. Total hardness concentrations were highest in the winter and lowest in the summer.
A hardness of about 275 ppm CaCO3 was the level usually found in Section II.
Bicarbonate
Bicarbonate values also were lowest in the summer and highest in the winter. The mean yearly level of bicarbonate in Section II was about 160 ppm CaCO3. This is slightly less than Section I, but still high by comparison to other North American waters (McKee and Wolf, 1963). The highest level recorded during the study was 222 ppm CaCO3 in December, 1965. The lowest reading (120 ppm CaCO3) was obtained in August and September, 1966.
Sulfate
Sulfate levels ranged from 135 to 375 ppm. The low occurred in April,
1967, and the high in January, 1967. The mean sulfate concentration during the investigation was about 260 ppm, which, similar to Section I is well
-31- above levels reported from most U. S. waters.
Chloride
The amount of chloride present in Section II remained fairly constant
during the study. Extremes were 10 and 20 ppm, the usual level was 15 ppm.
The lowest reading was recorded in April, 1967. As with other chemical
parameters, the highest levels of chloride occurred in the winter.
Electrical Conductivity
Specific conductance fluctuated from 496 to 1,009 micromhos as it reflected seasonal variations in the total mineral load of the Green River,
i.e, low in summer, high in winter. The conductance level was usually
about 680 micromhos, which is only slightly less than the mean value for
Section I (705 micromhos).
Hydrogen Ion
Hydrogen ion readings were relatively constant in this section. As
in Section I, values recorded were always alkaline with a range from 7.75
to 8.8. However, readings below 8.0 were found only occasionally. Unlike
other chemical parameters, pH levels were lowest in the winter and highest
in the summer.
Temperature
As in Section I, the only temperature data obtained was from spot checks.
A maximum of 72°F was recorded in August, 1966 but this temperature is not
necessarily the highest temperature that occurred. The minimum encountered
was 32°F, the usual under-ice temperature.
Bottom Fauna
The first samples of the aquatic invertebrate population in Section II
were taken in October, 1965 (Appendix 7). Subsequently there was a general
-32- Appendix 7 Average Number of Organisms Per Square Foot taken in Bottom Samples at Station II from October 1965 to April 1967
1965 1966 1967 10-18 11-17 12-18 2-15 4-16 8-10 9-14 10-22 11-18 1-18 4-17 , Hydracarina 0.7 0.3 2.0 3.0 1.0 Tubificidae 1.0 1.3 31.7 1.0 0.3 1.0 1.0 1.5 Other Oligochaeta 1.3 0.3 0.3 2.3 5.7 3.0 Hirudinea 0.3 Lymnaea 0.3 7.7 1.7 0.3 Physa 5.0 3.0 0.3 0.5 Pelecypoda 0.3 4.0 Nematoda 0.3 0.7 Tendipedidae 225.7 126.0 857.7 45.0 331.0 178.7 81.0 158.0 79.0 52.5 18.0 Simulidae 0.7 0.3 0.7 0.7 Tipulidae 0.7 0.3 Heleidae 1.3 0.3 4.0 1.0 Rhagionidae 0.3 0.3 1.0 0.5 Dolichopidae 0.3 Baetis 20.3 3.0 74.3 3.0 24.0 3.3 3.3 9.0 0.3 1.0 1.0 Tricorythodes 11.3 11.0 31.7 1.3 4.0 135.7 31.3 26.0 32.7 49.0 Ephemerella 29.3 27.7 299.7 37.0 191.3 2.7 8.0 90.0 9.3 5.5 1.0 Paraleptophlebia 1.3 3.7 2.7 0.7 0.7 7.0 0.7 3.0 Choroterpes 4.3 1.3 Rhithrogena 85.3 41.7 56.0 35.7 22.0 1.0 1.3 0.3 0.7 0.3 0.7 0.7 Heptagenia . 1.0 Perlidae 1.0 2.3 0.3 1.2 0,3 Perlodidae 2.0 9.3 1.3 2.7 0.3 6.0 1.3 Hydropsychidae 8.3 16.3 67.3 1.0 15.0 0.7 9.3 2.0 Hydroptilidae 3.3 0.3 Leptoceridae 0.3 3.7 1.0 Rhyacophilidae 0.3 0.3 Psychomyiidae 0.3 Elmidae 0.3 1.3 0.3 1.0 10.3 3.0 1.0 Other Coleoptera 4.0 Gomphidae 1.0 1.3 2.0 Pyralidae 0.3 Corixidae , 1.0
Avg. No. Per Sq. Ft.388#1 233.4 1,440.0 125.9 594.5 352.6 165.7 313.0 133.2 116.5 20.0 Avg. Vol. CC 1.0 1.0 2.6 0.4 1.9 2.5 1.5 2.4 1.1 0.2 0.1 No. Samples 3 3 3 3 3 3 3 1 3 2 1 No. Taxonomic Groups 14 13 20 11 14 17 25 13 15 11 3
-32A- downward trend until a sharp trend reversal occurred just prior to freeze-up,
(Figure 14). A peak level of 1,440 organisms per square foot was found in
December, 1965, but the benthic population again decreased in abundance after the river froze over. A spring peak of almost 600 organisms per square foot followed the winter low. Then the population exhibited a downward trend in numbers throughout the rest of 1966 and into the spring of 1967. The only exception was in October, 1966, when a brief upward trend occurred.
In spite of some sharp fluctuations, the benthic fauna at Station II appeared to be adequate as a source of fish food during the sampling period.
The benthic fauna seemed to be hard hit by the September 1965 flood but insufficient pre-flood sampling precludes any chance of before and after comparison. The aquatic flora in the section was sharply reduced by the flood. The relatively low level of aquatic fauna found in April, 1967, may have been due, in part, to fluctuations in river flows originating at Fontenelle
Dam.
The composition of the benthic fauna in Section II was relatively uniform during the study period (Figure 15). The midges (Tendipedidae) were the most abundance organism in the population, in which they composed at least 50 percent of any month's collecting. At various times mayflies of the genera Rhithrogena, Tricorythodes, Ephemerella, and Baetis were important components of the population The number of taxonomic groups ranged from
3 to 25. The low was recorded in April, 1967, the high in September, 1966.
The usual number of groups was about 14.
Fishery
The major fish sampling effort in Section II was made with dynamite in the fall of both years. These samples were supplemented by some gill
-33- netting, fishing and dynamiting at other seasons.
Composition, Abundance and Distribution
The species composition of the Section II fish population changed during the investigation (Figure 16). In FY 1966, the rainbow trout was by far the most common fish in the river. Flannelmouth suckers and carp composed about
30 percent of the population, less than half the population percentage represented by rainbow trout. A few Pantosteus suckers, whitefish, and
Utah suckers were also found, but the latter two species particularly were present in very limited numbers. In FY 1967, sampling indicated that there was a major population shift to flannelmouth suckers as the dominant species.
These fish increased from about 15 percent of the total catch in FY 1966 to almost 60 percent in FY 1967. Whitefish increased in abundance to rank second and rainbow trout dropped sharply from almost 70 percent in FY 1966 to less than 10 percent in FY 1967. In FY 1967 the numbers of carp observed decreased by about half. No other species were taken in FY 1967. The decrease in numbers of rainbow trout in the samples occurred in spite of persistent efforts to obtain an adequate trout sample. Frequently few or no trout were taken from "prime" holes where many were found in previous years.
Most of the non-game fish were found near the upper end of the section while the greatest numbers of rainbow trait were taken in the vicinity of
Big Island. Brown trait were not taken in the samples, but are known to have been present in occasional angler catches.
Length, Weight and Condition
Some change in length, weight and condition factor occurred in Section II fish during the study (Table 7).
-34- , , 11.11..111M arewmi 11.11MMIMMIN WO+ met wrio, 6 ,1'.111$.
Table 7. Mean Length, Weight and Condition (K) Data for Fish in Section II.
SPECIES Mean Length (mm) Mean Weight (gm) Mean "K" No. of Fish FY 1966 FY 1967 FY 1966 FY 1967 FY 1966 FY 1967 FY 1966 FY 1967
Rainbow 295 357 359 526 1.2716 1.1116 67 14
Whitefish 265 247 240 236 1.2897 1.1665 1 52
Flannelmouth Sucker 274 371 215 501 1.1327 0.9852 28 78*
Carp 333 490 1,057 1,842 1.8836 1.8711 28 7
Pantosteus Sucker 175 57 1.0636 3 1 w u-T i Utah Chub 334 420 1.1172 1
* 217 sub-sample of total number taken Table 8. Food Items of 51 Rainbow Trout Stomachs from Section II, Green River, 1965 - 1966 (all sizes combined).
FOOD ITEM VOLUME PERCENT
inorganic debris 11.50 2.8 organic debris 300.81 72.3 non-game fish 19.40 4.7 Mollusca 35.33 8.5 Cladocera and Copopoda 6.48 1.6 Ephemeroptera nymphs 1.51 0.4 Trichoptera larvae 5.45 1.3 Odonata nymphs 18.72 4.5 Coleoptera larvae 0.02 - Hemiptera 5.88 1.4 Amphipoda 4.34 1.0 Diptera larvae 0.58 0.1 Diptera adult 0.02 - Coleoptera adult 0.23 0.1 Hymenoptera 0.55 0.1 Hirudinea 5.20 1.2
TOTALS 416.02 100.0
-36- The average length and weight of Section II rainbow trout increased
62 mm (2.5 in.) and 167 gms (0.4 lb.) during the two year period. Total numbers of rainbow and their condition factor decreased, the former, considerably, the latter, slightly. The data indicates that while the rainbow population was smaller in numbers, the individual fish were larger in size in the last half of the study.
The size of the coarse fish increased from FY 1966 to FY 1967. Flannel- mouth suckers gained about 100 mm ( 4 in.) and 300 gms (0.7 lb.) and carp grew about 160 mm (6.2 in.) and 800 gms (1.8 lb.). The numbers of flannel- mouth suckers increased, but carp numbers decreased in the samples taken in
FY 1967.
Food Habits
The most common food item in 51 rainbow trout stomachs was organic debris
(72.37) (Table 8). Snails (Mollusca) were the most important animal segment of the trout diet, but non-game fish, dragonflies (Odonata), numphal forms,
Homoptera (true bugs), Microcrustaceans, scuds (Amphipoda), Trichoptera
(caddisflies) and Hirudinea (leeches) were all important food items. All of the non-game fish species present were found in the stomachs of the 300-350 mm
(12 - 14 in.) group of trout. No fish were consumed by the other size groups.
Organic debris was an increasingly important diet item in the larger size groups.
The 1965 stomach samples were collected after the September flood and were found to contain mostly organic debris and a few snails. This may indicate a shortage of food following the flood. The 1966 stomachs showed a wider ranger of food items including a reduction in organic debris and an increase in
Amphipods and Hemiptera.
-37- Age Composition
Attempts to age rainbow trout in the Green River provided unsatisfactory results during the initial stages of study. Age-growth analysis was difficult due to the irregular presence of spawning and planting checks on the scales.
During the second year of study, both scales and otoliths were used for age determinations. With all questionable scales thrown out, a total of 68 fish were used for age-length data (Table 9).
Table 9. Average Lengths for Each Rainbow Trout Age Class in Section II. Mean Length Age Class No. of Fish mm inches
I 7 254 10.0 II 31 274 10.75 III 13 341 13.4 IV 13 355 14.0 V 2 376 14.8 VI 2 428 16.8
About 46 percent of the rainbow trout in Section II were found to be two years old (two annuli present with growth prior to a third annulus). There was a sharp decrease in numbers older than four years. The majority of rain- bow trout in the section appear to be between two and four years old with a length range of 274 mm (10.75 in.) to 355 mm (14 in.). No fish were found to be older than six years plus.
Section III
Section III includes the Fontenelle Reservoir tailrace immediately below the dam. This section contains trout habitat that is probably the best in the lower river area. Except for some private lands located near and upstream from the Big Sandy River confluence, public access to the river is good and angling use is heavy at times. The area below the dam usually remains ice free and is popular with fishermen year round. The waters bounded by private lands
-38- are effectively fished from small boats.
Chemical and Physical
Slate Creek, the only tributary of consequence in Section III, often
dries up in late summer. This stream contributes a heavy load of silt and
alkaline materials to the main river during the spring run off, as do the
numerous dry washes throughout the section. Water samples taken at the
height of the spring run off showed a high turbidity level (1,750 ppm)
(Table 10).
Table 10. Water Chemistry of Slate Creek (in ppm).
Hardness DATE Total Ca Mg SO4 Turb. HCO3 pH °F Temperature
3-14-66 1,750 32 3-21-66 240 150 90 195 580 154 8.0 32
The greatest influence of Slate Creek on the main river appears to be its spring silt load. This may be an important factor relative to potential
rainbow trout spawning in the main river. The tailrace, above the Slate
Creek confluence, is usually clear in the spring.
Another main-stem source of water of undetermined importance is a series
of springs and seeps which have developed immediately downstream from Fontenelle
Dam. The amount of water flow appears to be directly proportional to the
amount of water stored in the reservoir. One such group of seeps and
springs forms a swampy pond area about one mile below the dam. The outlet
for this swamp has been fitted with a Parshall Flume by the Bureau of Reclamation
to measure the water flow. This short stream is commonly referred to as the
East Side Flume or Flume Creek. It appears to have an attraction to both
spawning and immature trout. Water in the flume differs considerably in
general composition from that found in the main river (Table 11) and is
notably higher in total hardness and sulfates. -39- , 00.1.00661 OW 10./ S 661•0111 1 00.00.6/ 11 ,1,0 0166.
Table 11. Water Chemistry (in ppm) and Physical Data for East Side Flume Creek and the Green River Upstream from the Mouth of Flume Creek.
HARDNESS o STREAM DATE Total Ca Mg SO4 Turb. Fe Cl HCO3 pH F Temperature
Flume Creek 4-27-66 514 360 154 1,050 0 0.04 40 222 8.0 48
Green River 4-27-66 274 190 84 190 8 0.08 15 171 8.75 42
Samples of Green River water in Section III were taken at the CCC Bridge about five miles downstream from Fontenelle Dam (Appendix 5).
Turbidity
Turbidity in Section III was usually less than 10 ppm. The highest reading obtained was 32 ppm in the spring of 1966. Spring turbidities are probably somewhat higher downstream from the sample site because of run off from the desert.
Hardness
Total hardness values were significantly lower in Section III as compared to the lower sections. The average total hardness, 213 ppm CaCO3, was about
25 percent less than that in the lower sections. As in the lower sections, calcium usually formed the greater part of total hardness; however, magnesium occasionally was present in levels almost equal to the calcium level. Magnesium values were highest in the late,fall/early,winter period and total hardness was also highest at that time. Total hardness ranged from 154 ppm CaCO3 to 274 ppm
CaCO3.
Bicarbonate
Bicarbonate values in Section III ranged from 120 ppm CaCO3 to 188 ppm
CaCO3. The average level during the period of study was just over 150 ppm
CaCO3. The average for Section III is about 6 percent lower than the average value in Section II and about 11 percent lower than that in Section I. The lowest values in Section III were recorded in the late summer-early fall, the highest in the winter. While bicarbonate concentration was generally lower than in the downstream sections, the conentration was high by comparison to other trout waters (McKee and Wolf, 1963).
-41- Sulfate
The mean concentration of sulfate during the study was 133 ppm in
Section III. This level represents a drop of about 53 percent from the mean concentration found in Section I and a drop of 49 percent from Section
II. This sharp decrease is probably due to the absence, in Section III, of tributary waters with the chemical composition of the Big Sandy River.
Sulfate concentration ranged from 75 ppm to 260 ppm. The high occurred in January, 1966 and appears to have been an exception as this parameter seldom exceeded 150 ppm during the study. Even at its lowest concentrations, the sulfate value is higher than that found in most U. S. waters (McKee and
Wolf, 1963)
Chloride
Chloride concentrations were quite stable and varied only from 10 ppm to 18 ppm during the study. The mean, about 13 ppm, places Section III at a level comparable to about 60 percent of good U.S. trout waters (McKee and
Wolf, 1963). The highest levels usually occurred in the winter.
Electrical Conductivity
The mean specific conductance value in Section III was about one third less than the mean values found in downstream sections. The mean was 466 micromhos with a range from 342 micromhos to 581 micromhos. These values place the water in the upper 50 percent of U.S. trout waters relative to conductance level (McKee and Wolf, 1963).
Hydrogen-Ion
Hydrogen-ion readings fluctuated from 7.75 to 8.9 in Section III but were generally over 8.25. Readings of less than 8.0 were usually found in the winter. There appears to be little difference in the hydrogen-ion
-42- concentrations of the different sections.
Temperature
As in the other sections, the only temperature data are from spot checks.
The highest temperature recorded at the CCC Bridge was 710F, the lowest was
34°F in the winter. The upper 5-10 miles of Section III did not freeze over during the winter because of the influence of Fontenelle Reservoir.
Bottom Fauna
Bottom fauna samples were taken at the CCC Bridge near Fontenelle. The only prior information on the bottom fauna at this site is that reported by
Bosley (1960). The river bed,in Section III,was thoroughly scoured by the
September 1965 flood. The bottom fauna and flora was predictably influenced.
Much, if not all,of the aquatic flora was swept away; especially affected were the heavy growths of aquatic plants in the backwaters. A jelly-like diatom established itself on the river bed soon after subsidence of the flood.
This diatom was very common at the sampling station and was the prevalent floral type throughout the sampling period. Other common aquatic plants became re-established during the summer after the flood.
The bottom fauna was at a relatively low level immediately after the flood (Appendix 8 and Figure 17) and remained so until the fall of 1966 when it increased several fold to about 1,700 organisms per square foot. Subsequently, the population slowly decreased to a low of 70 organisms per square foot in the spring 1967. There was very little variation in the benthic fauna during the first six months after the flood (Figure 18). Tentipedidae was by far the most common organism. Mayflies and buffalo gnats were scarce by comparison.
During 1966, invertebrate population dominance shifted first to the mayfly
Ephemerella and subsequently to the mayfly Tricorythodes. Tricorythodes
-43- Appendix 8 Average Number of Organisms per Square Foot taken in Bottom Samples at Station III from October 1965 to April 1967
1965 1966 1967 10-19 11-16 12-17 1-14 2-21 4-16 8-11 9-14 10-19 11-15 1-16 4-17
Gammarus 0.3 0.3 0.3 0.3 1.0 0.3 1.0 5.0 2.0 Cladocera 5.7 5.0 5.7 17.7 Copepoda 0.7 4.3 Hydracarina 0.7 10.7 24.3 7.0 8.0 Tubificidae 2.3 23.0 0.3 0.7 0.7 3.3 1.0 Other Oligochaeta 0.3 0.3 0.3 Lymnaea 0.3 36.3 27.0 13.3 4.7 1.0 Physa 6.0 7.0 2.7 6.0 3.0 1.0 Nematode 0.3 0.3 Tendipedidae 37.7 96.7 450.3 288.0 220.0 75.0 28.7 100.0 861.7 955.3 716.0 14.0 Simulidae 1.3 4.3 11.7 3.0 5.7 1.3 2.3 7.7 2.0 0.3 2.0 Tipulidae 0.7 0.3 0.3 Heleidae 0.3 Rhagionidae 0.3 0.3 0.3 Baetis 2.7 0.7 0.3 2.0 2.7 1.7 0.3 1.0 1.0 Tricorythodes 0.3 0.3 0.3 0.7 5.0 9.0 87.7 161.0 422.7 263.0 325.0 20.0 Ephemerella 6.0 10.7 19.0 14.0 29.0 118.0 8.7 291.0 154.0 124.0 31.0 Paraleptophlebia 0.3 0.7 0.7 Choroterpes 2.0 0.3 Rhithrogena 0.7 0.3 0.3 1.7 0.3 Perlidae 1.0 3.7 1.0 2.0 Perlodidae 0.3 0.3 0.3 2.0 Hydroschidae 2.7 8.7 5.7 Hydroptilidae 0.3 Lepidostomatidae 0.3 Leptoceridae 0.3 Elmidae 0.3 1.0 1.0 Gomphidae 0.7 1.0 Coenagrionidae 0.3 Avg. No. Per sq. ft, 49.3 115.6 504.6 306.6 261.9 203.6 173.4 340.0 1,645.4 1,427.8 1,184.0 74.0 Avg. Vol. (CC) 0.3 0.3 0.4 0.5 0.6 1.3 1.5 2.4 4.0 ------0.5 No. Taxonomic Group 8 8 6 7 10 5 1 20 23 21 10 1 No. Samples 3 3 3 3 3 3 3 3 3 3 1 1
-43A- numbers decreased in the fall of 1966 and Tendipedidae again was the most
common organism.
Examination of the benthic fauna and flora suggests that Section III is
quite productive from a fishery standpoint. The fact that the largest fish
are usually caught in Section III tends to support this impression.
Fishery
Although dynamiting was the principal method used to sample the fish
population in Section III, a significant number of trout was collected by
float fishing in the lower part of the section. Some electro-fishing with
an electro-fishing boat was also effected near the dam.
Composition, Abundance and Distribution
Rainbow trout were the most common fish encountered in the Section III
fish samples (Figure 19). The prevalence of this fish may be due,in part,to
the selectivity of collecting by float fishing. Only about half as many
rainbow trout were collected in FY 1967 as in FY 1966. Assuming that the
catch rate of fish sampling methods is density dependent, the data indicate
a decrease in the population of rainbow trout.
Brown trout were found infrequently in the samples. However, angling
records and a sample taken with the electro-fishing boat indicate that this
species may be more common than the results suggested by the regular samples.
The nucleus of the brown trout population appears to be centered in the five mile stretch below the dam.
Whitefish were taken more frequently in FY 1967 than in FY 1966 but do not seem to be present in large numbers.
Carp and flannelmouth suckers were encountered infrequently, except near
-44- the dam and in a few large sloughs near the Seedskadee Experimental Farm.
Large numbers of suckers and carp were reported in the pools and ponds near the dam outlet works especially when repair work on the dam required water reduction or removal in certain areas. All data indicate that the coarse fish population is centered in the area below the dam. This is,perhaps,a result of the curtailment of further upstream movement.
Bonytail chubs,found occasionally in Section III,were usually small and immature and were generally in backwaters. The low density of this species is surprising as it was expected that it would be increasing in abundance after the 1962 treatment. Scales from some specimens indicate that this species in the Green River is slow growing. It is possible that the chubs may be unable to compete successfully in the river environment. Utah suckers were present but rare in Section III samples.
Length, Weight and Condition
Section III fish population growth data show some changes from FY 1966 to FY 1967 (Table 12).
The data for rainbow trout are from summer float fishing and fall dynamiting only. Additional data collected on this species were excluded from the Table because of the possibility of a bias towards large fish. From FY 1966 to
FY 1967 increases of 11 percent in mean length and 7 percent in mean weight were noted for rainbow. The mean condition factor of the species dropped sharply (23 percent). No length-weight data were obtained for brown trout.
The data for the whitefish population do not permit valid comparison because of the paucity of whitefish in FY 1966.
Non-game fish (suckers, carp, bonytail) were relatively uncommon in Section
III. The length-weight data that were obtained suggest a rapid increase in the
-45- non-game fish biomass. The average carp taken in FY 1967 was nearly twice as heavy as that in FY 1966. The increase in average weight of flannelmouth suckers was even more marked. This increase in biomass is probably a function of a low density of coarse fish, a further indication of the coarse fish populations relatively slow recovery from the 1962 rotenone treatment.
Food Habits
The rainbow trout in Section III appear to be consuming a wider variety of food items than those in Section II (Table 13). Organic debris was again the most common food item in the stomachs (547w) Of the animal segment of diet, caddisflies (Trichoptera), dragonflies (Odonata), snails (Mollusca), and non-game fish were the most important items. As in Section II, the bulk of the 1965 diet was made up of organic debris which may have been a function of flood-caused food shortages. Caddisflies were the most important animal food in the 1965 diet, but were rarely found in 1966. The major animal food items in 1966 were dragonfly nymphs, snails, and non-game fish. The fish segment of diet was found only in stomachs from trout over 400 mm (16 in.).
More specifically relative to size, trout over 400 mm seemed to be feeding upon larger items such as fish and dragonfly nymphs; snails and caddisflies were important food for trout between 300 and 400 mm and fish eggs, caddisflies, and Hemiptera (true bugs) were most important to fish under 300 mm (12 in.).
The fish eggs probably represent food provided by illegal chumming and are a typical diet item.
Age Composition
Questionable scales and otoliths were eliminated in preparing age-length data for Section III (Table 14).
Of 59 trout analyzed from Section III, about 49 percent were three year
-46- Table 12. Average Length, Weight and Condition of Fish in Section III during Fiscal Years 1966 and 1967
Mean Length (mm) Mean Weight (gm) Mean "K" No. of Fish Species FY 1966 FY 1967 FY 1966 FY 1967 FY 1966 FY 1967 FY 1966 FY 1967
Rainbow Trout 311 350 479 516 1.4057 1.0883 57 38
Whitefish 311 323 320 425 1.0238 0.9839 1 37
Flannelmouth Sucker 308 389 86 612 0.8365 0.9669 8 9
Carp 473 - 1,695 2,854 1.6906 1.9252 3 6
1 Bonytail 150 - 30 - 0.8056 - 1 --]---- 1 Table 13. Food Items of 32 Rainbow Trout Stomachs from Section III, Green River, 1965 - 1966
FOOD ITEM VOLUME PERCENT organic debris 194.40 54.2 non-game fish 18 80 5.2 undetermined fish 1.20 0.3 Mollusca 25.11 7.0 Ephemeroptera nymphs 0.09 Plecoptera nymphs 1.00 0.3 Trichoptera larvae 66.10 18.4 Odonata nymphs 48.21 13.4 Hemiptera 0.22 0.1 Amphipoda 1.43 0.4 Diptera larvae 0.24 0.1 Coleoptera adult 0.05 Hymenoptera 0.15 fish eggs 2.00 0.6
TOTALS 359.00 100
-48- old fish at least 350 mm (13.75 in.) in length. Although no trout were examined from the one-year age class, creel checks indicate the presence of a distinct size group (about 10 in,) which is probably the one year fish.
The data confirm earlier field observations indicating the presence of several distinct size groups in the catch: 254 mm (10 in.), 356 mm (14 in.),
457 mm (18 in.), and 533 mm (21 in.). No rainbow trout over seven years of age were examined. The largest and oldest trout from the Green River, examined during the study, was seven years old, 605 mm (23.8 in.) long and weighed over eight pounds.
Table 14. Average Lengths for Each Rainbow Trout Age Class in Section III. Mean Length AGE CLASS NO. OF FISH mm inches
I 0 - II 12 330 13.0 III 29 350 13.75 IV 9 383 15.0 V 4 467 18.4 VI 3 468 18.4 VII 2 531 20.9
Section IV
Section IV is a relatively minor section established primarily to provide a necessary, but limited degree of surveillance on various physical, chemical and biological factors which might influence Fontenelle Reservoir. The section includes the Green River proper upstream from the head of Fontenelle Reservoir to the mouth of the New Fork River and the New Fork River upstream to its confluence with the East Fork River.
Chemical and Physical
In general, the water in Section IV was found to carry a lighter chemical load than the downstream sections. An exception was the level of bicarbonate concentration which was slightly higher in Section IV than below the reservoir
(Table 15). -49-
Table 15. Mean and Extreme Values (ppm) of Green River Water Chemistry, Section IV, (Names Hill Only), 1965 - 1967.
HARDNESS
Total Ca Mg HCO3 SO4 Cl Cond. Turb. pH Temperature
Mean 196 118 91 161 78 11 396 10 8.3
Minimum 137 90 64 120 63 6 291 2 7.25 32
Maximum 240 150 123 188 87 25 462 180 8.8 70 Bottom Fauna
Samples of the invertebrate fauna were taken from two stations. The
lower station was at Names Hill just upstream from Fontenelle Reservoir. The
upper station was on the New Fork River. Both stations were the same as
described by Binns (1965, 1967).
The benthic fauna at the Names Hill station was at a comparatively low
level when checked in the fall of 1965 (Appendix 9). There is a strong but
indeterminable possibility that this station was flooded briefly by the upper end of Fontenelle Reservoir. This flooding, if it occurred, may account for the low population level.
After the fall of 1965, the benthic fauna appeared to fluctuate on an annual basis (Figure 20). The peak population (1,320 organisms per square foot) occurred in April, 1966.
The midges (Tendipedidae) were usually the dominant organism present
(Figure 21). Exceptions occurred in the late fall, in the winter and in the spring when mayflies of the genus lphemerella were prevelant. Mayflies of the genus Rhithrogena and caddisflies of the family Hydropsychidae were also among the more common groups, although they were never dominant.
The benthic fauna at the New Fork River station exhibited an increasing numerical trend from 1965 to 1967 (Appendix 10 and Figure 22). The peak of abundance occurred in October, 1966, when 2,296 organisms per square foot were found. A peak in August, 1966, was 854 organisms per square foot which was about twice the level recorded in August, 1964. This general increase probably indicates that the stream fauna has made considerable recovery from the effects of the 1962 rotenone exposure. The lowest faunal level recorded during the present study was 9 organisms per square foot in August 1965.
-51- Appendix 9 Average Number of Organisms per Square Foot taken in Bottom Samples at Station IV from September, 1965 to April, 1967 1965 1966 1967 9-23 10-19 11-16 12-17 2-18 4-27 8-11 9-14 10-19 11-18 1-18 4-18 Hydracarina 0.7 0.7 3.0 1.0 Tubificidae 2.0 0.3 1.0 0.3 0.3 0.7 1.0 Other Oligochaeta 0.3 0.3 0.5 1.0 Lymnaea 0.3 Nematoda 0.3 Tp•ndiDedidae 53 62.7 41.7 3.7 737.0 5.0 133.2 159 216.0 398.5 901.0 75.0 Simulidae 0.7 0.3 1.0 0.3 0.3 0,7 1.0 Heleidae 1.3 1.0 Rhagionidae 0.3 1.3 0.3 1.0- 1.7 0.7 4.7 5.0 Baetis 3.0 2.7 7.0 0.7 5.0 3.7 1.7 5.0 2.0 Tricorythodes 1.3 1.0 0.3 13.0 12.7 5.0 37.7 56.3 84.0 6.0 Ephemerella 7.0 60.3 59.7 23.3 525.5 43.7 4.0 39.7 91.3 273.0 369.0 Paraleptophlebia 0.7 0.7 7.5 0.3 4.3 20.7 10.0 8.0 Choroterpes 0.3 Rhithrogena 3.3 24.7 15.7 6.3 1.0 5.0 8.3 8.3 Heptagenia 0.3 1.0 1.7 2.0 7.0 5.0 Pteronarchidae 0.3 0.7 0.3 0.5 0.7 1.0 Perlidae 0.3 1.3 13.0 2.0 2.3 1.0 Perlodidae 1.0 6.3 2.3 0.3 0.7 0.7 2.7 4.0 1.0 Hydropsychidae 1.0 4.0 1.0 29.5 0.7 26.0 68.7 31.3 28.7 11.0 5.0 Brachycentridae 0.5 0.3 Hydroptil'dae 1.7 Lepidostomatidae 0.3 0.3 0.3 3.0 0.3 2.3 5.0 1.0 Leptoceridae 0.3 0.3 1.7 1.7 1.0 Elmidae 0.3 0.5 0.3 1.7 2.3 1.0 Gomphidae 0.3 0.3 0.5 0.3 0.3 0.3 0.7 3.0
Avg. No. per Sq. Ft.73.8 165.9 129.6 35.1 1,320 52.0 183.9 265.7 353.1 641.8 1,292 476 Avg. Vol. (CC) 0.2 0.9 0.8 0.1 2.2 0.6 0.4 0.9 0.8 1.0 2.0 2.4 No. Taxonomic Groups 14 15 12 9 13 8 12 18 16 19 12 13 No. Samples 3 3 3' 3 2 3 3 3 3 3 1 1
-51A- Appendix 10 Average Number of Organisms per Square Foot taken in Bottom Samples at Station V from August 1965 to April 1967
1965 1966 1967 __ __ _ Hydracarina 0.7 4.7 1.0 Tubificidae 0.3 0.3 5.7 0.3 0.3 Other Oligochaeta 0.3 1.0 Lymnaea 0.3 0.3 2.0 0.3 0.7 19.0 Tendipedidae 1.0 18.3 11.0 92.3 2.7 19.7 75.0 38.0 673.3 101.0 1,979.7 1,599.0 785.0 96.0 Simulidae 0.3 0.3 0.7 0.5 3.0 Tipulidae 1.3 1.7 1.0 1.7 3.7 2.5 2.3 5.0 2.0 Heleidae 2.0 2.0 2.0 Rhagionidae 0.3 0.3 1.0 1.7 0.3 3.3 1.5 4.0 5.0 4.0 2.0 Baetis 2.5 4.7 0.3 0.7 0.7 1.7 4.0 15.3 1.5 0.3 1.0 5.0 Tricorythodes 0.3 0.3 0.3 0.3 0.3 4.3 0.5 1.0 2.0 1.0 1.0 Ephemerella 2.0 15.7 47.0 7.0 27.0 51.0 52.7 8.3 8.5 34.7 26.0 59.0 33.0 Pharaleptophlebia 0.3 3.0 11.0 1.0 4.0 Choroterpes 1.0 Rhithrogena 3.0 41.0 82.3 56.3 15.0 2.7 11.7 34.7 3.0 4.5 29.3 23.0 1.0 3.0 Heptagenia 2.3 1.0 Pteronarchidae 1.7 2.0 0.3 1.0 3.0 3.7 0.3 2.0 Perlidae 0.3 0.3 0.7 0.7 3.7 5.5 8.3 5.0 7.0 4.0 Perlididae 3.3 13.3 11.0 3.7 0.7 4.7 30.0 1.3 4.5 28.7 45.0 17.0 23.0 Nemouridae 0.7 H dropsychidae 1.5 16.0 14.3 38.7 2.3 22.0 59.0 8.0 99.7 48.0 53.0 29.0 55.0 20.0 Brachycentridae 0.3 0.3 0.3 0.7 Hydroptilidae 0.5 0.3 6.0 0.5 66.3 129.0 1.0 Lepidostomatidae 3.7 7.0 8.3 0.7 1.0 6.7 3.3 1.3 7.0 45.0 103.0 7.0 5.0 Leptoceridae 0.3 0.5 4.7 1.0 1.0 Rhyacophilidae 0.3 2.0 6.0 5.2 0.7 1.0 1.0 0.7 1.0 Elmidae 1.3 3.0 1.0 1.7 2.0 1.3 16 14.5 25.9 49.0 12.0 6.0 Other Coleoptera 0.3 1.0 Gamphidae 0.3 Pyralidae 0.5 Corixidae 0.3 .
Avg. No. per Sq. Ft. 9.0 92.8 152.7 263.3 32.0 84.5 221.3 178.9 853.9 200.8 2,296.3 2,056.0 957.0 208 Avg. Volume (CC) 40.1 0.4 1.0 2.4 0.3 1.1 2.4 2.1 2.4 0.7 3.9 5.7 1.7 4.5 No. Taxonomic Croups 6 13 18 14 8 13 15 16 21 17 25 19 16 16 No. Samples 2 3 3 3 3 3 3 3 3 2 3 1 1 1
-51B- Much of the 1966 numerical increase was due to increases in numbers of midges (Tendipedidae). Tendipeds became the dominant organism in August,
1966, and thereafter made up the largest segment of the population (Figure 23).
The mayfly genus, Rhithrogena, was the prevalent organism in 1965 The mayfly genera, Ephemerella and Baetis; the caddisfly families, Hydropsychidae,
Hydroptilidae and Lepidostromatidae; the stonefly family, Perlodidae; and the riffle beetle family, Elmidae also occurred at various times as one of the three most numerous organisms. Of interest is the return to comparative abundance of the caddisfly family, Hydropsychidae. This group evidently was very adversely affected by rotenone exposure in 1962.
Fishery
Fish sampling efforts ,in Section IV ,were confined to the New Fork River where attempts were made to obtain carp for identification tagging. A shortage of carp prevented satisfactory completion of the tagging experiment, but gill net catch data provided the following information on species composition in backwater areas. Brown trout made up 417 of the catch; rainbow trout, 317; flannelmouth suckers, 237; and carp, whitefish, and bonytail chubs, 27 each.
Data obtained from main stream dynamite sampling in August 1967 indicate the following composition: whitefish, 64%; flannelmouth sucker, 207; brown trout, 127; and rainbow trout, 67g.
Exploitation of the Green River Fishery
Since the 1962 rotenone rehabilitation, the Green River ,downstream from
Fontenelle Reservoir ,has become know for its good trout fishing. Prior to the rotenone treatment, the river supported very little fishing pressure. In
1964 and 1965 the river produced high quality fishing and was very popular with
-52- fishermen. Unfortunately, there was no meaningful creel census data available
for angling use and success prior to 1966. A regularly scheduled ground and
aerial creel census was made during the summer of 1966 to provide some idea of fishing pressure and success.
Fishing pressure is known to have been heavy in October, 1965, after the
September flood. Success at that time was fair to good. In 1966, the May through September catch rate ranged from 0.35 trout per hour to 0.64 trout per hour for Area I and from 0.123 trout per hour to 0.42 trout per hour for
Area II. The mean catch per hour was 0.54 for Area I and 0.29 for Area II
(Tables 16 and 17). The ground census indicates that Area II received heavier useage in spite of a lower success rate.
Rainbow trout caught in Area I averaged 283 mm in length as compared to an average length of 342 mm in Area II. Simple statistical analysis verifies an impression that the mean length of trout caught in Area I is different from the mean length of the catch in Area II. It also indicates: 1) that the trout population in Area I is generally a different size than that in
Area II; and 2) that the mean length of the catch varies from month to month in both areas. The latter indication supports the possibility that anglers were harvesting from different size groups of fish in different months. In the case of Area I, the general trend was a decrease in average length as the summer progressed. In Area II, the length increasedto a peak in July and then decreased. Potential causes of such variation in average length may be: 1) the extermination of "phasing-out" of a dominant, larger sized age class; 2) entrance into the fishery of a young, smaller sized age class; and/or 3) emigration of the larger fish from the area. All three factors are probably important, but the disparity between lengths in Areas I and II suggests that upstream migration
-53- may be removing the larger fish from Area I. If the larger fish are moving upstream,the colder, less alkaline water near the dam may be an important attractive factor.
Results of the 1966 aerial fisherman counts indicate that Area II receives its heaviest usage in the morning, while both areas receive about equal pressure in the late afternoon. A reason for this use pattern may be the fact that Area I is close to local population centers and probably receives the "after-work" fishermen, while Area II receives most of its use from non-local people who camp in the fishing area. The aerial counts indicated that the river received its heaviest use in July, which,locally,has two major holidays. Angler use was also relatively heavy on the Labor Day week-end. Many of the holiday fishermen are from the northern Utah and
Colorado population centers.
Trout Movement
During the study a total of 3,703 rainbow trout were tagged and released in the Green River at various sites between Fontenelle Dam and Green River
City. The majority of the tagged trout were catchable-size, hatchery fish released in 1966.
A total of 243 tags were recovered by September 1, 1967, representing a return of approximately 6.5 percent. Of the tagged trout re-captured, 63 percent of the total were caught at the release site and 95 percent of the total were caught within five miles of the release site. The longest migration reported was 70 miles downstream from the release point. Several 20 to 40 mile migrations were also recorded. In general, upstream movement was slightly more common than downstream movement.
A total of 794 rainbow trout were tagged and released in the upper end
-54- of Flaming Gorge Reservoir to check on potential trout spawning migrations into the Green River. All 27 tag returns representing a three percent recovery to September 1, 1967, were from down reservoir areas. The longest movement was
60 miles. About half of the tagged trout moved 20 to 30 miles from the release site.
Numerous complaints were received from fishermen regarding damage to trout caused by the "dart" and Peterson tags. One Peterson tag wound was examined nine months after release date and was still not healed. Only a few of the "dart" and Peterson tags were recovered, possibily due to excessive mortality or tag loss.
Spawning
The limited information collected on trout spawning activity indicates that there may be an upstream spawning run of undetermined magnitude into the area below Fontenelle Dam. A small concentration of rainbow trout moved into Flume Creek in the late fall of 1965 in what appeared to be a spawning attempt. Several tags subsequently recovered from these fish showed that they moved back downstream as much as ten miles. Later a few young brown and rainbow trout were recovered from Flume Creek. Electro-fishing,near the mouth of Flume Creek in the spring of 1967, revealed the presence of several sexually ripe rainbow trout, one of which was a male tagged several miles downstream.
From the study to date, it would be difficult to ascertain whether any of these fish represent a major spawning run or a local resident population.
DISCUSSION
Fontenelle Reservoir appears to be a typical, small, alkaline reservoir.
In the reservoir's relatively short history, it has fluctuated rapidly from maximum to minimum levels. Probably because of this fluctuation no thermocline
-55- has formed. There is some evidence to suggest the presence of chemical stratification when the reservoir is full. However, this may be related to chemical or thermal densities created by the inflow currents of the Green
River.
Seasonal plankton blooms occur in the reservoir, but to date, there has been no sign of the problem algae, Aphanizomenon flos-aquae.Mougeotia and
Cladocerans seems to be the principal plankters. A Mougeotia bloom was especially noticeable prior to the 1965 evacuation. The plankton samples indicate that this evacuation caused disruption in plankton development. The change from this evacuation caused disruption in plankton development. The change from a relatively deep lake to a pond with considerable littoral area, resulted in a shift in dominant plankters (Figure 24).
The bottom fauna is very uniform in composition with only a few species present, but in sufficient numbers for an adequate fish food supply. The midge larvae (Tendipedidae) were often found in large numbers.
Most of the fish fauna consists of cyprinids and catostomids, which are considered to be "trash fish". Carp and flannelmouth suckers appear to be well established and reproducing. Although they are well established, carp as yet, are not overly numerous in the reservoir, but their population will probably increase greatly once the reservoir is stabilized. Reduction of the reservoir to minimum pool is a probable important limiting factor for its fish fauna. During the study, both whitefish and brown trout numbers decreased in gill net catches from the minimum pool, facts which may indicate that the warm, shallow, lentic environment was unsuitable.
Salmonids comprise about 25 percent of the fish fauna. Rainbow appear to be the principal trout species, but brown trout also are quite important to the
-56- relatively limited, but successful fishery which has developed in the reservoir area since evacuation. The salmonid population appears to be decreasing, probably because of a combination of initial heavy angler exploitation and a policy limiting stocking until the reservoir level stabilized.
Maintenance of the reservoir at a comparatively stabile level in 1966 resulted in a surprisingly well developed and diversified aquatic flora.
Potomogeton, Elodea, and Myriophyllum were a few of the common species found, and because of food abundance the reservoir was an important waterfowl area.
As would be expected, Fontenelle Reservoir exerts a major influence on its tailwater, the Green River. Generally, the reservoir has a moderating influence on the river. This is especially true with regard to water tem- peratures. The river below the dam is usually cooler in the summer and warmer in winter than in the downstream areas. Because of winter warming, the river, near the dam, is usually ice-free and provides early spring fishing of considerable interest to local anglers. In the same area, the summer cooling factor may be an important incentive to trout emigration from warmer waters downstream. The fact that this below-dam area generally has adequate trout populations while downstream waters have relatively fewer fish tends to support this theory.
The September, 1965, evacuation of Fontenelle Reservoir produced down- stream flood conditions of more than double normal spring flood levels. The effect on the river's fauna and flora was catastrophic. Post-flood investiga- tions showed evidence of severe scouring and consequent reduction of the biota. Unfortunately, the flood occurred prior to most of the trout tagging program so that no information on movement is available and little is known about the game fish reactions to the high water. However, post-flood deteriora- tion of lower river trout populations is an indication that some flood caused
-57- downstream movement occurred.
As indicated above, the paucity of rainbow trout in the lower river may be a function of several factors. Flood induced migration downstream into
Flaming Gorge Reservoir may have been an important cause of river fishery deterioration. Some emigration, or even mortality, may have resulted from excessively high water temperatures. Relative to this theory the condition of rainbow trout held in aquaria was observed to deteriorate sharply at temperatures above 78°F which is slightly higher than 76°F temperatures in the lower river. There is some evidence to suggest the presence of important river-bottom spring flows near Big Island. This area is also one of the stream's better trout population centers, a fact which as in the case of waters below the Fontenelle Dam suggests the relative importance of water temperature and quality to the river's trout concentrations. Additional causes for the sparse numbers of trout in the lower river may be inadequate natural recruitment, poor dispersal of hatchery fish from planting sites, and a reduced stocking program.
The effect of the 1965 flood on the benthic fauna apparently was temporary.
The numbers of aquatic invertebrates returned to normal population levels soon after flood conditions subsided. One exception was observed in the area below the dam, where the numbers of bottom fauna species remained low for almost a year following the flood. However, part of this reduction, which was accompanied by an unusual diatom bloom, may have been due to the influence of a general habitat change created by the Fontenelle impoundment complex.
The data indicates that the Green River, between the two reservoirs, is heterogeneous in its biological, chemical and physical features. Section I appears to be the least productive of the three river sections. Benthic
-58- invertebrate populations and fish fauna are relatively sparse. Extremes in
chemical parameters, and in such physicol features as temperature and siltation,
are among the important factors inhibiting productivity. An important change
in the quality of the Green River occurs with the intake of the Big Sandy
River. The saline, mineralized water of this tributary exerts a marked
influence on the main river in both Sections I and II, In Section III, above
the Big Sandy confluence, chemical and physical conditions appear to be much
closer to those optimum for trout habitat.
The study data suggest that there are marked differences in the biological
productivity of various reaches of the river. The CCC Bridge-Fontenelle Dam
area, the Tollman Ranch area, and the Big Island area all appear to have good
production of both trout and fish-food organisms with the latter the best
producer of aquatic invertebrates. The Big Island area productivity may be
related to a well developed moss-Chara-algae substrate cover. The upper part
of Section III has produced the biggest trout, but all three of these areas
have provided reasonably good fishing.
The Green River at present has three main centers of fishing pressure:
1) The Green River City area.
2) The Big Island area.
3) The Fontenelle Town area.
This pattern of fishing pressure distribution may be related to public access
availability as bridges, in all three areas, provide easy access to both river
banks.
1
-59- Table 16. Green River Creel Census Summary, 1966
All Months Area 1 May June July August September Combined
I II I II I II I II I II I II
Number Fishermen 47 77 96 78 83 53 41 96 0 24 267 328
Number Hours 119.5 386.5 219.75 281.75 193.0 142.5 54.75 400 50.74 587 1,261.5
Number Rainbow 42 161 120 69 119 45 35 49 - 29 316 353
Number Brown 0 3 0 6 0 0 0 1 0 10
Average Hours for Fishermen 2.60 5.02 2.29 3.62 2.33 2.69 1.34 4.17 - 2.11 2.20 3.85
Catch: Trout per Hr. 0.35 0.42 0.55 0.27 0.62 0.32 0.64 0.123 - 0.59 0.54 0.29
Average Length of Catch (mm) 306 338 282 357 300 373 252 307 294 283 342
1. Area I: Green River City to Big Island Bridge. Area II: Big Island Bridge to Fontenelle Dam. Table 17. Aerial Fishermen Counts on the Green River from Flaming Gorge Reservoir to Fontenelle Reservoir during June, July, August, and September, 1966
(Section I = Flaming Gorge Reservoir to Big Island Bridge; Section II = Big Island Bridge to Fontenelle Dam.)
Total number Fishermen Number Fishermen Flaming Gorge Reservoir Each Area to Fontenelle Reservoir Date Area A.M.* P.M.* A.M. P.M.
June 29 WD* both 23 35 23 35
July 3 WE I 42 80 II 119 84 161 164
July 9 WE I 37 64 II 40 67 77 131
July 20 WD I 20 26 II 20 27 40 53
July 24 WE I 22 60 II 85 48 107 108
Aug. 6 WE I 18 35 II 31 42 49 77
Aug. 17 WD I 28 20 II 7 16 35 36
Aug. 21 WE I 9 53 II 55 42 64 95
Sept. 4 WE I 31 71 II 56 78 87 144
* A.M. flight start at 9:00 at head of Flaming Gorge Reservoir and go upstream P.M. flight start at 5:00 at Fontenelle Dam and go downstream
** WD = Weekday WE = Weekend
-61- Figure 1. Map of the Green River Study Area Showing Sections and Locations of Benthic Sample Stations.
r\lge Fork River Station
Big Piney.
Section=
Station EL Fontenel le Cree Fontene lie Reservoir Slate CC Bridge
Fontenelle Station DI 1 Big Sandy River Sectionli
Station itt Big Island Bridge Se.ctionII Alkali Creek
Green River C t Bitter Creek Station I Section I Blacks Fork Big irehole Creek Flaming Gorge Reservoir
-62-
Figure 2. Monthly Surface Area at Fontenelle Reservoir from July, 1965 to July, 1967.
8,500
7,500
6,500
5,500
4,500
3,500 ACRES -
2,500
SURFACE AREA 1,500
ASONDJFMAMJJASOND F MAMJ 1 965 1966 1967
- 63- Figure 3. Mean Weekly Discharge of the Green River at the Fontenelle Dam Gage from July, 1965 to September, 1966.
12,000 _
LOPOO _
8,000 k o 6,000 _ IL U I w 0 cr 4000 - 4 , I U U) 6 >-- _J Y u j 2,000 w
z < w 2
0 NA
1965 1966
-64- Figure 4. Map of Fontenelle Reservoir Showing Maximum (B) and Minimum (A) Water Levels. ii — Green River
Fontenelle Creek
A
Fontenelle Dam
-65- Figure 5. Fontenelle Reservoir Water Chemistry as Related to Depth in August, 1965.
CO 2 - PPM 0 5 1 0 15 20 0 - PPM 2 4
1 0
20
30
40
50
60
FEET PH
- 7.0 7.5 8.0 8.5 9.0 T.11. & CACO3- PPRN 50 100 1 50 200 DEPTH \ I —T. H. 1 0 /
20 1 HCO 3 30 \[
40
50
60
-66- Figure 6. Seasonal Fluctuations in Fontenelle Reservoir Water Chemistry from August, 1965 through May, 1967. 9.0— 1 0 ppm T1. 8.0 5 - OXYGEN
(,-) 7.0 0
a a
w 300 30
TOTAL 0 HARDNESS
200 20 E a. a.
Iii
0 100 E
0 co TOTAL HARDNESS 0 0 SUMMER, FALL, WINTER, SPRING, SUMMER, FALL, WINTER, SPRING, 1965 1965 1966 1 966 1 966 1 966 1 967 196 7
-67- Figure 7. Plankton Abundance in the Surface to Ten Foot Strata of Fontenelle Reservoir from August, 1965 to May, 1967.
1600
1400
cr 1000 w a. TOTAL PLANKTON 800
600 \
400
200 NUMBER OF ORGANISMS
Lo Lo LO N. t■ LD 1.0 (0 Lo (D LI) i i A I c■.I a) Cr) .— CV. 0) CV N N i I I I ..— CV' ■ ill DATE
-68- Figure 8. Vertical Distribution of Plankton in Fontenelle Reservoir in August, 1965 and 1966.
AUGUST 1965 AUGUST / 1966
(LINE THICKNESS I ndicates Abundance)
II Number of Plankters Per Liter 0 Number of Taxonomic Groups Per Liter
-69- Figure 9. Composition of the Fontenelle Reservoir Fish Population as Indicated by Gill Net Catches in the Fiscal Year 1966 and 1967. (July 1 to June 30).
100'-
FY 1966 80
GO
40
20
0
FY 1967
ft 0 40
20 ■ 111111 a- 3 °/e 1.5°4 0.9°4 0.6•/. 0 • El Rainbow Trout D Carp 111 Fl annel m out h Sucker ▪ Brown T rout El Bonytail Chub E9 Pantosteus sp. • Whitefish Utah Chub
-70-
Figure 10. Length Frequency of Rainbow Trout in Fontenelle Reservoir as Indicated by Gill Net Catches in Fiscal Years 1966 and 1967 (July 1 to June 30)
8-
FY 1967
1 \ I 5 - \ 1 / t 4 - I I I A A / I A / ■ I \ / t It I / \, \ / t t t V 1_ _ _ .../ I v) 3 - 1 / Li. I 1 % i 1 St 1 I 11_ i ‘ • 0 2 - - -, I 1 -/ 1 I r I 1 /- w 1 / w I I 1 / I- _J V 2 o z 1 i l l 1 j I III I 1 I I i o 441 Lc) In 0 Ln in in- in in in in in In 0 v u) co 0 co co 0 cm oscm cm cv cv C" el vr xt LENGTH- MM
-71- Figure 11. Mean Lengths Attained at Various Ages by Rainbow and Brown Trout in Fontenelle Reservoir. Age As Determined from Scales and Otoliths taken from Gill Net Caught Trout.
500 - #
# # / RAINBOW / TROUT ., 400 -- .------\ ...- .. \ .. - BROWN TROUT I 300 /
I I 2 200 I 2 I i I I I I ^ I I / I 2 I , I t 1 1 1 t l I 11 III .1Z 3L ME MI AGE (No.of Annuli)
-72- Figure 12. Number and Volume of Organisms in Square Foot Bottom Samples taken at Station 1 from October, 1965 through April, 1967. 350
300
NO.
25 0
200 I I / I 1 I T (f) I— I 0 i 0 I I I CC/ 1L- 1 50 I
I VOL. - Ui I
100
/ c0 2 50 N / CENTRIFUGED VOLUME
O N D J F M A M J J A S O N D J F M 1965 1966 1967
-73- Figure 13. Composition of Square Foot Bottom Samples taken at Station 1 from October, 1965 through April, 1967.
IA 80 a-
60
20
11-16-55 - 17- G 7 o Tendipedidae Tricorythodes Hydropsychidae Tubificidae Baetis Ephemerella Fl GI ossosomat i dae _1/ Tubifi cidae/ Baetis,& Pcrlodidac 14 Ephoron El Rhithrociena Other Oligochaeta Hydropti!idae & Gomphidae _Q_ no. taxonomic groups present (0) no. organisms / sq.ft.
-74- Figure 14. Number and Volume of Benthic Organisms in Square Foot Samples taken at Station II from October, 1965 through April, 1967.
GOO 1440
NO
500
VOL
2 T.
400 i 1 F 1 / 1 / r I SQ. 1- t
O I I' 1 i C o V IL 300
<
0 200 1 liJ CENTRIFUGED
LU
0 N D A J J A 0 D J F M A 1965 1966 1967
-75-
Figure 15. Composition of Square Foot Bottom Samples taken at Station II from October, 1965 through April, 1967.
100— 1 4 1 3 20 11 1 4 1 7
80 ( 233.9) (1440.0) (125.9) (594.5) (352.6) -
60
40 _J < O 20
0 10-18-65 11-17-65 1 2-18-65
100 ^ 25 13 1 5 11 3 (1G5.7) ( 313.0) (133.2) (116.5) ( 20.6) CR 80 A.
GO
40
20
9-14-66 1 0-22-66 11-18-6G 1-18-67 4-17-67 LI TENDIPEDIDAE TRICORYTHODES JJ RHITHROGENA EFMIDAE BACTIS EPHEMEREL I A LYMNAEA NO. OF TAXONOMIC • 111 00 GROUPS PRESENT ( 00) NO. ORGANISMS / SQ.FT-
-76- Figure 16. Composition of the Fish Population in Section II of the Green River as indicated by Samples during the Fiscal Years 1966 and 1967 (July 1 to June 30)
LI Rainbow Trout El Whitefish an Utah Sucker Flannelmouth Pantosteus Carp Ins Sucker (00) Number of Fish
-77- Figure 17. Number and Volume of Benthic Organisms in Square Foot Samples taken at Station III from October 1965 through April 1967.
6
NO. 1500 5
1200 4
SO.FT.
0 0 CC/ L, 900 3
VOL. a GOO er cc LIJ \ 2 300 CENTRIFUGED
AT, r. ■ •••
I I 1 I I I I I O N DJ F M A M J J A S O N DJ F M 1 965 1 966 1 967
-78- Figure 18. Composition of Square Foot Bottom Samples taken at Station III from October, 1965 through April, 1967. 1 00-
8 6 7 1 0 5 80 ( 49.3) ( 504.6) (306.6) (203.6) —
GO
40
20 ^ _J
0 iswplimatoN 111 -714 F- 0-19-65 11- 16-65 1 2 -17-65 1-14-66 2- 21-66 4-16 - 6 6 Ij 0
z 100 ^ LIJ 1 2 20 23 21 1 0 7 (173.4) ( 340.0) (1645.4) (1427.8) (1184.0) (70.0) cc 80 a_ GO
40
20
0 8-11- 66 9-14-G6 1 0-19-66 11-15-66 1 -16-67 4-17- 6 7 ,••■■■•••••■•■ El Tendipedidae El Tricorythodes Simulidae 47.40. Tubificidae Baetis Ephemerel [ID Lym n aea la (00) No. Organisms! Sq. Ft. 00, No Taxonomic Groups Present -79-
Figure 19. Composition of the Fish Population in Section III of the Green River as indicated by Samples during Fiscal Years 1966 and 1967 (July 1 to June 30)
1 00 FY 1967 ( 390) 80
GO
40
-J 20 0 REM III0.5°I 0.5°IIII H O
• 100,-
FY 1966 U 80 (122) cc 60
20
1111111 7-15-1 Rainbow Trout Flannelmouth Utah Sucker 0 Sucker M ko Brown Trout a Carp 1:11 Bonytail Chub Whitefish ( 00) Number of Fish
-80- i-- 8 L. CY cc w 2 D M < z M W n 2 M
800 600 2
00 / / / / 0 1965 N \
% Figure \ \ \ \
I 1
20. / i 1 i i
1
i
I I I Number andVolumeof Samples takeninSectionIVfromSeptember, April, I I I
A '
\
I
1
‘
\
\
‘
1967.
\
\ \ \ k....
......
Benthic J -81- 1966 J Organisms inSquareFoot 1965 through mime
1 3 2
2
CENTRIFUGED VOLUME-CC/ SQ.FT. 411•••■ 1 4 15 1 2 9 1 3 (73.8) (165.9) (129.6) ( 35.1) (1320.0) ( 52.0) 80
60
p••■•, 40
20
0
LL 0
Z 100— W 12 1 8 1 6 1 9 1 2 1 3 (183.9) ( 265.7) ( 353.1) ( 641.8) (1292.0) (476.0)
^
20 ^
8-11-66 9 -14 -66 1 0-19-66 11-18-66
EL TENDIPEDIDAE EPHEMERELFA PARALEPTOPHEBIA A PEN F I DAE
TRICORYTHODES RHITHROQENA HYDROPSYCHIDAE ( 00) NO. ORGANISMS / SQ.FT.
00 NO. TAXONOMIC GROUPS PRESENT -82- Figure 22. Number and Volume of Benthic Organisms in Square Foot Bottom Samples Taken at Station V from August, 1965 through April, 1967. 2400' - A / It
200 It 5
NO.
1600 I- 0 0 IL cc 1200 VOL,
••■• •••••••• °- 800 2 I FUGED 2
400R- CENTR
4 LI
0 1 I I I I L I I I I 0 A S O N D J FM AMJ J A S O N D J F MA 1 965 1 966 1 967
-83- Figure 23. Composition of Square Foot Bottom Samples taken at Station V from August, 1965 through April, 1967.
I- 0
16 21 1 7 25 1 9 1 6 1 6 (178.9) (853.9) ( 200.8) (2296.3) (2056.0) ( 957.0) (208.0)
40
20
2°4 3°4 2°4 111=4 • - - 4- 27-66 8 - 11 - 66 9-19-66 1 0 20 - 66 11 18 - 66 1 -19-67 4-17- 67
ID Tendipedidae ffi Ephemerelis pi Hydro sychidae Lepidostomatidae E9 Elmidae II Baet is RI Rhithrogena Ul Hydroptilidae D Period i dae (00) No. Organisms / Sq. Ft. 00 No. Taxonomic Groups Present -84- -
Figure 24. Dominant phyto and zooplankters of the Upper 10 Feet of the Pelagic Zone at Fontenelle Reservoir from August 10, 1965 to May, 1967.
1 00
80
60
40
< 20 0 F-- 0 IL 0
60
40
20
PHY TO- ZOO- ZOO - PHYTO - ZOO - PHY TO - 8-29-66 11-17-66 2- 21- 67
Mougeotia • Ceratium Copepoda nauphi Rotatoria ▪ Cladoccra • Fraqilaria 110 Spae racy st i s Navicula 1\1 Volvox • Tabellaria Elm AstrioneHa sp Cop epoda
-85- BIBLIOGRAPHY
Binns, Allen, et al. The Planning Operation and Analysis of the Green River Fish Control Project. Cheyenne and Salt Lake City, Wyoming Game and Fish Department and Utah State Department of Fish and Game. 1963. 83p.
Binns, Allen. The Effects of Rotenone Treatment of the Fauna of the Green River, Wyoming. M.S. Thesis, Corvallis, Oregon State University, 1965. 258p.
. Green River-Fontenelle Reservoir to Flaming Gorge Reservoir, 1966. Cheyenne, Wyoming Game and Fish Commission, Progress Report No. 1. 22p.
. Effects of Rotenone Treatment on the Fauna of the Green River, Wyoming, 1967. Cheyenne, Wyoming Game and Fish Commission, Fisheries Research Bulletin No. 1. 114p.
Bosley, Clifford E. Pre-impoundment Study of the Flaming Gorge Reservoir, 1960. Cheyenne, Wyoming Game and Fish Commission Fisheries Technical Report No. 9. 81p.
Eiserman, Fred, et al. Flaming Gorge Reservoir Post-impoundment Investigations, 1966. Utah and Wyoming Game and Fish Departments, Progress Report No. 3. 96p.
McKee, J.E., and H. W. Wolf. Water Quality Criteria, 2nd ed., 1963. Sacramento, California State Water Quality Control Board. 548p.
Stone, Roderick, and Kent Miller. Glen Canyon Post-impoundment Investigations, 1965. Utah State Department of Fish and Game, Progress Report No. 3. 56p.
U.S. Geological Survey. Water Resources Data for Wyoming, part 2, Water Quality Records, 1965. Worland, Wyoming, U.S. Geological Survey. 131p.