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Eric E. Kofoot

Publications and source records attributed to Eric E. Kofoot.

6 recordsLinked to original sources
USGS2016

Evaluation of the biological and hydraulic performance of the portable floating fish collector at Cougar Reservoir and Dam, Oregon, September 2015–January 2016

The biological and hydraulic performance of a portable floating fish collector (PFFC) located in the cul-de-sac of Cougar Dam and Reservoir, Oregon, was evaluated during 2015–16. The PFFC, first commissioned in May 2014, was modified during winter 2014–15 to address several deficiencies identified during operation and testing in 2014. These modifications included raising the water inflow structures to reduce the depth and volume of inflow to improve the internal hydraulic profiles, and moving the anchors so the PFFC could be positioned closer to the existing reservoir outlet, a water temperature control tower. The PFFC was positioned about 18 meters (m) upstream of the intake of the water temperature control tower and faced into the prevailing water current. Like several floating surface collectors operating in the Pacific Northwest at the time, the PFFC used pumps to draw water and fish over an inclined plane, past dewatering screens, and into a collection area. The portable and experimental nature of the PFFC required a smaller size, shallower entrance (about 2.5-m deep), and smaller inflow rate (72 cubic feet per second [ft 3 /s] inflow during the Low treatment, 122 ft 3 /s during the High treatment) than other collectors in the region. The collection of the target species, juvenile Chinook salmon ( Oncorhynchus tshawytscha ) , during 2015–16 was an order of magnitude larger than in 2014. Subyearling-age Chinook salmon comprised most of the catch (2,616 subyearling compared to 258 yearling) and was greatest during the spring during the High inflow treatment. Bycatch consisted predominantly of cyprinids and centrarchids. Trap mortality (fish found dead in the trap) of juvenile Chinook salmon, at 9.2 percent of the subyearlings and 5.0 percent of yearlings, was about 30 percent of the level in 2014. Fish mortality from handling the live catch was about 1 percent. Data from fish tagged with passive integrated transponder (PIT) tags and those with acoustic+PIT tags released near the head of the reservoir indicated the catch rates of the PFFC were low. Eight of the 1,497 PIT-tagged fish and 5 of the 534 acoustic+PIT-tagged fish were collected by the PFFC. Fish collection efficiencies—the number collected by the PFFC out of the number detected at the head of the forebay (FCE FB ) or in the cul-de-sac (FCE CDS ) —were 0.002 and 0.003 during the Low treatment and 0.008 and 0.009 during the High treatment. The low FCEs were attributed to the following factors: Few acoustic+PIT-tagged fish were detected within 10 m of the PFFC entrance, Most fish were detected between the stern of the PFFC and the entrance to the tower, Fish depths commonly were several times greater than the PFFC entrance depth, and Surface water temperatures were warm. The data suggest that the shallow entrance and low inflow rate reduced fish guidance near the PFFC entrance and the hydraulic characteristics resulting from the outflow plumes (and perhaps water entering the temperature control tower) attracted fish to that area. Catch of juvenile Chinook salmon likely would increase if the collector entrance were deepened, the inflow rate were increased, and measures were taken to constrain fish presence to the area upstream of the trap entrance.

Oregon↗
USGS2015

Behavior, passage, and downstream migration of juvenile Chinook salmon from Detroit Reservoir to Portland, Oregon, 2014–15

An evaluation was conducted to estimate dam passage survival of juvenile Chinook salmon ( Oncorhynchus tshawytscha ) at Detroit Dam during a period of spill. To estimate dam passage survival, we used a paired-release recapture study design and released groups of tagged fish upstream (997 fish) and downstream (625 fish) of Detroit Dam. A total of 43 fish (6.8 percent) passed Detroit Dam from the upstream release group and passage occurred through regulating outlets (54.8 percent), spill bays (31.0 percent), and turbines (14.3 percent). We do not present dam passage survival estimates from 2014 because these estimates would have been highly uncertain due to the low number of fish that passed Detroit Dam during the study. Secondary objectives were addressed using data collected from tagged fish that were released at the downstream release site. Juvenile salmonids have multiple passage options at the Bennett Dam complex, which includes a series of dams and braided channels. A pair of Passive Integrated Transponder (PIT) monitoring arrays were installed at Upper Bennett Dam and in the Stayton Canal by the U.S. Army Corps of Engineers and the Oregon Department of Fish and Wildlife during 2014. We deployed acoustic telemetry hydrophones near these arrays to detect acoustic-tagged fish from our study and used these detections to quantify proportions of tagged fish passing through the two routes. About one-fourth (0.257) of the tagged fish that were released downstream of Big Cliff Dam were detected on the new PIT tag array while passing the Bennett Dam complex. A total of 402 acoustic-tagged fish were detected at the complex and many (248 fish; 62 percent) eventually entered the Stayton Canal. Median residence time in the canal was 6.5 hours, but 12.7 percent of the fish had extended residence times (7–37 days). Passage also was monitored at the Sullivan Project at Willamette Falls and about 40 percent (0.398) of the tagged fish passing the project were detected on the PIT tag array. A Cormack-Jolly-Seber mark-recapture model was developed to provide reach-specific survival estimates for juvenile Chinook salmon. A portion of the tagged population overwintered in the Willamette River Basin and outmigrated several months after release. As a result, survival estimates from the model would have been negatively biased by factors such as acoustic tag failure and tag loss. Data from laboratory studies were incorporated into the model to provide survival estimates that accounted for these factors. In the North Santiam River between Minto Dam and the Bennett Dam complex, a distance of 37.2 kilometers, survival was estimated to be 0.844 (95-percent confidence interval 0.795–0.893). The survival estimate for the 203.7 kilometer reach between the Bennett Dam complex and Portland, Oregon, was 0.279 (95-percent confidence interval 0.234–0.324), and included portions of the North Santiam, Santiam, and Willamette Rivers. The cumulative survival estimate in the 240.9 kilometer reach from the Minto Dam tailrace to Portland was 0.236 (95-percent confidence interval 0.197–0.275).

Oregon↗
USGS2014

Behavior and dam passage of juvenile Chinook salmon and juvenile steelhead at Detroit Reservoir and Dam, Oregon, March 2012-February 2013

The in-reservoir movements and dam passage of individual juvenile Chinook salmon ( Oncorhynchus tshawytscha ) and juvenile steelhead ( Oncorhynchus mykiss ) were studied at Detroit Reservoir and Dam, near Detroit, Oregon, during 2012 and 2013. The goal of the study was to provide data to inform decisions about future downstream passage alternatives and factors affecting downstream passage rates with the existing dam configuration. In 2012, 468 juvenile Chinook salmon and 200 juvenile steelhead were tagged and released during a 3-month period in the spring, and another 514 juvenile Chinook salmon were tagged and released during a 3-month period in the fall. The fish were surgically implanted with a small acoustic transmitter with an expected life of about 3 months and a passive integrated transponder tag with an indefinite life, and were released into the two main tributaries several kilometers upstream of the reservoir. Juvenile Chinook salmon migrated from the release sites to the reservoir in a greater proportion than juvenile steelhead, but once in the reservoir, juvenile steelhead migrated to the forebay faster and had a higher dam passage rate than juvenile Chinook salmon. The routes available for passing water and fish varied throughout the year, with low reservoir elevations in winter and high reservoir elevations in summer in accordance with the flood-control purpose of the dam. Most dam passage was through the spillway during the spring and summer, when the reservoir elevation was high and the spillway and powerhouse were the most common routes in operation, and via the powerhouse during the fall and winter period, when the reservoir elevation was low and the regulating outlet and powerhouse were the most common routes in operation. Few tagged fish passed when the powerhouse was the only route in operation. Dam passage rates during the spring and summer were greatest at night, increased with dam discharge, and were greater when water was passed freely over the spillway compared to when it was controlled by the spillway Tainter gates. Dam passage rates during the fall and winter, when the reservoir elevation usually was too low for spillway operation, were lower than during the spring and summer, negatively related to reservoir elevation, and positively related to dam discharge, though the latter relation diminished as reservoir elevation decreased. Fish locations near the dam from estimates of three-dimensional positions often were near the locations of dam discharge and fish depths were surface oriented relative to the depth of the forebay. Fish passage rates with the existing dam configuration were greatest when the spillway was in operation and were lowest when the powerhouse was the only route in operation; the latter result may be related to the relatively low magnitude or variability in discharge during that condition. The available data suggest that a properly designed surface outlet could be a viable passage route for juvenile Chinook salmon and juvenile steelhead at Detroit Dam. A second year of data collection based on a similar study design was complete at the time of this report.

Oregon↗
USGS2014

Behavior and dam passage of juvenile Chinook salmon at Cougar Reservoir and Dam, Oregon, March 2012 - February 2013

The movements and dam passage of individual juvenile Chinook salmon ( Oncorhynchus tshawytscha ) were studied at Cougar Reservoir and Dam, near Springfield, Oregon, during 2012 and 2013. Cougar Dam is a high-head flood-control reservoir with a temperature control tower as its outlet enabling selective withdrawals of water at various depths to control the temperature of water passed downstream. This report describes the second year of a 2-year study with the goal of providing information to inform decisions about future downstream passage alternatives. Inferences were based on the behavior of yearling-size juvenile Chinook salmon implanted with acoustic transmitters. The fish were released near the head of the reservoir during the spring (March, April, and May) and fall (September, October, and November) of 2012. Most tagged fish were of hatchery origin (468 spring, 449 fall) because of the low number of wild fish captured from within the reservoir (0 spring, 65 fall). Detections at hydrophones placed in several lines across the reservoir and within a collective system used to estimate three-dimensional positions near the temperature control tower were used to determine fish behavior and factors affecting dam passage rates. Most tagged fish made repeated non-random migrations from one end of the reservoir to the other and took a median of 3.7–11.7 days to travel about 7 kilometers from the release site to within about 100 meters of the temperature control tower, depending on season and origin. Reservoir passage efficiency (percentage of tagged fish detected at the head of the forebay) was 97.8 percent for hatchery fish and 74.2 percent for wild fish. Tagged fish commonly were within about 100 meters of the temperature control tower, and often spent considerable time near the entrance to the tower; however, the dam passage efficiency (percentage of dam passage of fish detected at the head of the forebay) was low for fish released during the spring (11.1 percent) and moderate for fish released during the fall (58.1 percent for hatchery fish, 65.2 percent for wild fish) over the 90th percentile of the empirically determined tag life, which was about 90 days. The primary factors affecting the dam passage rate were diel period, dam discharge, and reservoir elevation, and most passage occurred during conditions of night, high dam discharge, and low reservoir elevation. Most fish entering the temperature control tower passed the dam without returning to the reservoir. The common presence of tagged fish near the tower entrance and high proportion of dam passage after tower entry suggests that the primary cause of the poor dam passage rate was the low rate of tower entry. We hypothesize that fish reject the tower entrance because of low water velocities contributing to a small flow field, an abrupt deceleration at the trash rack, or a combination of those two conditions. Results of a controlled test of head differential (the difference between water elevation outside and inside the temperature control tower) indicated weak statistical support (P= 0.0930) for a greater tower entry rate when the differential was 0.65–1.00 foot compared to 0.00–0.30 foot. Results from hatchery and wild fish were similar, with the exception of the reservoir passage efficiency, indicating hatchery fish were suitable surrogates for the wild fish for the purpose of this study.

Oregon↗
USGS2002

Conditions for growth and survival of bull trout in Beulah Reservoir, Oregon. Annual report 2001

The Bureau of Reclamation (BOR) constructed Agency Valley Dam on the North Fork of the Malheur River in 1934-35, creating Beulah Reservoir. The project is operated and maintained by the Vale Irrigation District for irrigation and downstream flood control, with no minimum pool or outflow operational criteria. Although the project is not operated for fish and wildlife values, the reservoir supports a rainbow trout Oncorhynchus mykiss fishery and also seasonally harbors an adfluvial population of bull trout Salvelinus confluentus (Oregon Department of Fish and Wildlife [ODFW]; Burns Paiute Tribe). Bull trout were listed by the USFWS as a threatened species throughout the Columbia and Klamath river basins in 1998, and Oregon has listed the North Fork Malheur River population “Of Special Concern”.

Oregon↗