SOLAR- POWERED SCREEN PROTECTS FISH IN YELLOWSTONE NATIONAL PARK

ASSOCIATION OF CONSERVATION ENGINEERS 2000 Proceedings

SOLAR- POWERED SCREEN PROTECTS FISH

IN YELLOWSTONE NATIONAL PARK

James J. Strong1 Daniel L. Mahoney2

ABSTRACT

1 President, Aquadyne, Inc. P.O. Box 189 Healdsburg, CA 95448

2 Fishery Biologist, Yellowstone National Park, WY 82190

Reese Creek, the northernmost tributary of the Yellowstone River, located in Yellowstone

National Park, is the only stream in the park system that has had water diverted from it for

private irrigation purposes. As such, various stretches of Reese Creek have been subjected to

dewatering. With these exceptions, however, Reese Creek fisheries habitat has been rated as of

moderately high quality. Major dewatering of Reese Creek coincided with the spawning

migration of various species of fish such as : cutthroat trout, rainbow trout, brown trout, brook

trout, and mottled sculpin. As a result of dewatering, successful incubation, hatching, emergence

from gravel, and fry to the Yellowstone River appeared to be negligible at one point. Since there

are only a limited number of spawning tributaries in the upper Yellowstone River, the National

Park Service in 1991 embarked on a program to improve conditions on Reese Creek that were

detrimental to fisheries habitat. At that time, three concrete diversion structures on Reese Creek

were constructed to replace three wood and metal structures that were no longer functioning

properly. Also included was the installation of government furnished metal work which included

self-powered, self-cleaning overshot type fish screens, slide gates on each concrete structure, and

two parshall measuring flumes with concrete wingwalls located above and below the diversion

structure. Because the hydraulic characteristics of the concrete structure did not allow for the

necessary eight-inch head loss available to operate the overshot screens, the screens never did

operate properly. In 1999, the National Park Service retrofitted the overshot screens to enable

them to function by means of solar power. Results after one year of operation are presented.


INTRODUCTION

In 1997, the National Geographic magazine chose the Yellowstone River as “The Last Best

River” in the United States. Flowing freely for 670 miles, the Yellowstone River is the longest

river in the lower-48 states without a single dam. First made famous by Lewis and Clark’s Corps

of Discovery for its spectacular scenery, abundant wildlife, and thriving fish populations, the

Yellowstone River sadly last year also joined the American Rivers list of “Most Endangered

Rivers”.

The threat comes as landowners, downriver from Yellowstone National Park (YNP), have sought

to prevent natural seasonal flooding through environmentally detrimental “bank stabilization”

techniques, including “rip-rap” lining the stream with huge piles of boulders. Not only does bank

stabilization alter the Yellowstone River’s natural course and increase flow velocities, it also

changes the function of the river by not allowing it to reach the floodplain and serve as a natural

seed spreader and habitat protector for native fish, such as cutthroat trout, and other riparian-

dependent species.

Other threats to the Yellowstone River come in the form of agricultural withdrawals from various

tributaries which limit the reproductive success of resident and salmonid populations. About

twelve tributaries of the Yellowstone River between YNP and Livingston, Montana are used by

salmonids for spawning. In 1932 the northern boundary of YNP was expanded to include the

entire Reese Creek drainage. The purchase of the land, however, did not include the water rights

to Reese Creek or its tributaries. Reese Creek is the northernmost tributary of the Yellowstone

River within the YNP border, and is the only stream within YNP in which water is removed by

private landowners for irrigation purposes which continues to this day.

DISCUSSION

In 1984, YNP initiated studies to monitor stream discharge and fish distribution in order


to assess the effects of irrigation and complete dewatering on the aquatic resources of Reese

Creek. Both resident and adfluvial populations of salmonids use Reese Creek during the year. It

was suspected that water-taking limited the spawning success of these populations by allowing

fry to move into the diversion ditches and become cut-off from the stream’s main stem, isolating

them in small pools, and stranding trout redds when the creek is completely dewatered. Later

studies have described the physical habitat of Reese Creek, magnitude and duration of the

Yellowstone cutthroat trout ( Oncorhynchus clarki bouvieri ) spawning run, and population

characteristics of the resident cutthroat trout population. Results from these studies indicated

that without adequate streamflow, spawning success of salmonids moving from the Yellowstone

River into Reese Creek and subsequent fry survival would be severely reduced.

Reese Creek has been routinely dewatered completely below the very first diversion. On

several occasions minimum flow recommendations were made. In 1991, an agreement was

reached stipulating minimum flows of 0.037 cubic meters per second (cumecs) (1.31 cubic feet

per second-cfs) during the spawning season, depending upon the discharge upstream from the

diversions being at least 0.079 cumecs (2.79 cfs). For the other six months of the year, the

available discharge would be 50% of whatever was available.

In fall of 1991 the old diversion structures were removed and replaced with adjustable V-

notched fish ladders, irrigation ditch headgates, and cylindrical self-cleaning fish screens. These

screens, however, did not function properly because of insufficient available head and became

clogged with debris. Normal operation of a rotating self-powered, self-cleaning overshot fish

screen relies on the passage of water through an intake divider which directs flow to turbine-type

vanes on both sides of the screen drum. The screen is then rotated operating on the principal that

water flow plus head equals power. Debris is carried over the screen and washed downstream.

The rotating drum turns approximately 14 times per minute when installed with the proper

amount of head.

As mentioned previously, the hydraulic characteristics of the concrete structure erected in

1991, when the screens were originally installed, did not allow for the head loss required to


operate the overshot screens properly. In 1992, there was one incident of complete dewatering

reported. To remedy this situation, the two overshot screens at two separate diversions on Reese

Creek were retrofitted to solar power operation utilizing photovoltaic cells to create electricity

directly from sunlight. Photovoltaic modules generate direct current (DC) when exposed to

sunlight or other sources of light. The photovoltaic modules along Reese Creek were placed

during installation to a fixed position to approximate the ideal point when facing the sun in order

to generate maximum power

In 1999 the National Park Service reinitiated monitoring of Reese Creek. Project

objectives included:

1) install and monitor the effectiveness of retrofitted solar powered self-cleaning fish screens,

2) monitor fish use and fry emergence, and 3) determine effectiveness of fish passageways.

Study Area.

Reese Creek originates at Cache Lake and flows approximately 11.5 km (7.15 m) to its

mouth at the Yellowstone River. Electric Peak and Sepulcher Mountain respectively form the

western and eastern boundaries of the drainage basin. Downstream of the third diversion riparian

vegetation consists of cottonwood (Populus spp), Rocky Mountain juniper (Juniperus

scopulorum), sagebrush (Artemesia spp), rose (Rosa spp), and willow (Salix spp).

Three irrigation diversions are located in the lower reaches of the stream at 0.8, 1.6, and

2.0 Km (0.5, 1.0, and 1.5 m) upstream from the mouth of Reese Creek. The diversions are

referred to as the first, second, and third diversion, respectively. Fish passageways are located at

the first and second diversions. A cylindrical, galvanized steel culvert is located under the

Stephens Creek Road. Staff gauges and parshall flumes have been installed in two locations; one

downstream of the first diversion, and the other approximately 200 m (660 ft) upstream of the

third diversion (Figure 1). Differences in discharge at the two sites have been used to estimate

the amount of water being taken from the stream.


Fish species that occur in Reese Creek include Yellowstone cutthroat trout, rainbow trout

(Oncorhynchus myskiss), brown trout (Salmo trutta), brook trout (Salvelinus fontinalis), mottled

sculpin (Cottus bairdi), and mountain whitefish (Prosopium williamsoni). Yellowstone cutthroat

trout/rainbow trout hybrids are also found in Reese Creek. Upstream of the third diversion to the

confluence with Electric Creek, Reese Creek may contain a resident population of salmonids.

Electrophorectic analysis of 22 specimens tested in 1990 indicated that the 16 individuals were

pure Yellowstone cutthroat trout, while the other six showed signs of hybridization with rainbow

trout. From Electric Creek upstream to the stream’s source at Cache Lake appears to be fishless.

Several potential barriers are found throughout this stretch of water (Varley 1976). Cache Lake

is also reported to be fishless despite stocking 14,000 brook stout, and 300,000 Yellowstone

cutthroat trout between 1912 and 1929 (Varley 1981).

Methods.

The Reese Creek study area was divided into six reaches extending upstream from the

mouth at the Yellowstone River to the third diversion. From the mouth upstream to the first

diversion was divided into sections one, two, and three. The area between the first and second

diversion was divided into sections four and five. Section six was established between the

second to the third diversion (Figure 1). Diversion ditches were sampled separately from the

main stem of the stream. Data were recorded under DI, DII, and DIII for the diversion ditches.

Electrofishing was used to sample fish from 21 May to 14 October 1999. Captured fish were

visually identified to species, measured (total length mm), weighed (g), and when possible

identified to sex and stage of maturity. Trout containing meristic characteristics of both

Yellowstone cutthroat trout and rainbow trout were considered hybrids. Fish were given a

section specific clip to monitor movement throughout the creek. All trout that were ripe or

nearly ripe were counted as spawners. All salmonids > 80 mm (3.15 in) in total length that were

unable to be identified as to species were counted as fry.

Fish screens were installed in all three diversions on 14 July 1999. Solar- powered, self-

cleaning, rotating fish screens were installed in diversions two and three (Figures 2 and 3), and a


non-rotating screen that needed to be manually cleaned was installed in diversion one. Solar

panels were mounted on large poles and wired to a deep cycle battery to supply it with a constant

charge; the battery was wired to a small motor that rotated the screens. Due to the small size of

diversion one, and the surrounding tree cover, the manual screen was selected over a solar-

powered, self-cleaning screen.

Results.

Five species of fish, as well as cutthroat/rainbow trout hybrids were collected in Reese

Creek during electrofishing surveys. Cutthroat/rainbow trout hybrids were the most abundant

fish captured (42%), followed by mottled sculpin (28%), brown trout (13%), rainbow trout

(12%), Yellowstone cutthroat trout (3%), and brook trout (2%). Unidentified trout fry were also

collected during the sampling season (Table 1). Fish were captured in highest numbers below

the first diversion (16.76 fish/ 100m) and lowest between the first and second diversions (5.97

fish/ 100m). Between the second and third diversion fish were captured at a rate of 11.25 fish/

100m.

Spawning Yellowstone cutthroat trout, rainbow trout, and cutthroat/rainbow hybrids were

captured from 21 May to 23 July 1999. Sampling of the stream did not take place from 23 July

until 13 August, and no spawning fish were captured in later sampling efforts, indicating the

spawning had ceased sometime between these two dates. Spawning cutthroat, rainbow, and

hybrids were captured in all study sections. Trout fry were most abundant on 20 August, which

correlated with peak water temperature (Figure 4). Young of the year and adult brook trout were

captured in the early part of the sampling season as far upstream as the third diversion. No

spawning brown trout or brown trout fry were captured during surveys.

Shocking of the first and third diversion after the installation of fish screens produced

only one fish. An unidentified trout fry was captured in the first diversion following the

installation of the retrofitted fish screens. No fish were captured in the third diversion.

Diversion two was dry throughout the sampling season. Clipped fish were captured both above

and below the section in which they were marked.


CONCLUSION

Installation of fish screens has prevented the migration of fry into the diversion ditches.

Only one fry was captured in the first diversion after the installation of the fish screen. It is

possible that this fish entered the area between the screen and the diversion headgate while the

screen was removed for cleaning. No trout were collected in the third diversion.

Fish passageways appeared to work as planned. Clipped fish were found both upstream

and downstream from the section in which they were clipped. Sculpin, however, were absent

above a small cascade located at the end of section one, suggesting that they were unable to

maneuver over the cascade. (Figure 5). One trout was collected in the first diversion ditch after

installation of the new screens. Preventing Reese Creek from being completely dewatered has

had positive effects on the fish population in the stream. An increase in the number of spawning

fish and distribution of size classes indicates that Yellowstone cutthroat trout, rainbow trout,

brook trout and cutthroat/rainbow hybrids have been spawning successfully in Reese Creek for

several years (Table 2). Declining numbers of fry captured in the lower sections of the stream as

the season progressed suggests that fry do not spend a significant amount of time in Reese Creek

and quickly disperse downstream into the Yellowstone River. The area above the second

diversion was not sampled on enough occasions to determine fry use and dispersion in this area.

SOLAR- POWERED SCREEN PROTECTS FISH IN YELLOWSTONE NATIONAL PARK

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