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Title: A model of the effects of flow fluctuations on fall Chinook salmon spawning habitat availability in the Columbia River

Abstract

Previously we reported that about 30% to 60% of the area predicted to be used by fall Chinook salmon (Oncorhynchus tshawytscha) for spawning in the Hanford Reach of the Columbia River did not contain redds. One explanation for the overprediction of habitat was that our model did not incorporate streamflow fluctuation. Daily fluctuation in flow caused by load-following operations (power generation to meet short-term electrical demand) at Priest Rapids Dam, situated at the upper end of the Hanford Reach, changes the hydraulic characteristics to which fish respond in selecting redd sites. The purpose of the study described here was to examine the effect of flow changes on spawning habitat modeling and, in particular, to look at the connection between spawning and the variability and persistence of habitat variables caused by rapid changes in flow resulting from load-following operations at Priest Rapids Dam. We found that spawning habitat use by fall Chinook salmon was consistent with previous fall Chinook salmon studies in the Reach. Dynamic variables that were based on hourly time series were used to account for the variability in habitat as a result of flow fluctuations. The analysis showed that the proportion of velocities that fell within the rangemore » of 1.0 to 2.5 m/s differed significantly between locations that were predicted to be spawning by the logistic regression model where spawning actually occurred and locations that were predicted to be spawning where spawning did not occur. However, the resulting sequential logistic regression model that incorporated the dynamic variables did not provide significant improvement in the percentage of errors for areas predicted to be spawning; the model’s overprediction errors still ranged from 63% to 78%. We suggest that while flow fluctuation may affect spawning habitat and individual fish behavior, the high correlation between time-averaged velocities and the proportion of hourly velocities that fell within the most favorable range negated any improvements in model predictions.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
949918
Report Number(s):
PNNL-SA-55022
400480000; TRN: US200909%%475
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: North American Journal of Fisheries Management, 28(6):1894-1910; Journal Volume: 28; Journal Issue: 6
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; MATHEMATICAL MODELS; COLUMBIA RIVER; FLOW RATE; FLUCTUATIONS; HABITAT; SALMON

Citation Formats

Geist, David R., Murray, Christopher J., Hanrahan, Timothy P., and Xie, YuLong. A model of the effects of flow fluctuations on fall Chinook salmon spawning habitat availability in the Columbia River. United States: N. p., 2008. Web. doi:10.1577/M07-074.1.
Geist, David R., Murray, Christopher J., Hanrahan, Timothy P., & Xie, YuLong. A model of the effects of flow fluctuations on fall Chinook salmon spawning habitat availability in the Columbia River. United States. doi:10.1577/M07-074.1.
Geist, David R., Murray, Christopher J., Hanrahan, Timothy P., and Xie, YuLong. 2008. "A model of the effects of flow fluctuations on fall Chinook salmon spawning habitat availability in the Columbia River". United States. doi:10.1577/M07-074.1.
@article{osti_949918,
title = {A model of the effects of flow fluctuations on fall Chinook salmon spawning habitat availability in the Columbia River},
author = {Geist, David R. and Murray, Christopher J. and Hanrahan, Timothy P. and Xie, YuLong},
abstractNote = {Previously we reported that about 30% to 60% of the area predicted to be used by fall Chinook salmon (Oncorhynchus tshawytscha) for spawning in the Hanford Reach of the Columbia River did not contain redds. One explanation for the overprediction of habitat was that our model did not incorporate streamflow fluctuation. Daily fluctuation in flow caused by load-following operations (power generation to meet short-term electrical demand) at Priest Rapids Dam, situated at the upper end of the Hanford Reach, changes the hydraulic characteristics to which fish respond in selecting redd sites. The purpose of the study described here was to examine the effect of flow changes on spawning habitat modeling and, in particular, to look at the connection between spawning and the variability and persistence of habitat variables caused by rapid changes in flow resulting from load-following operations at Priest Rapids Dam. We found that spawning habitat use by fall Chinook salmon was consistent with previous fall Chinook salmon studies in the Reach. Dynamic variables that were based on hourly time series were used to account for the variability in habitat as a result of flow fluctuations. The analysis showed that the proportion of velocities that fell within the range of 1.0 to 2.5 m/s differed significantly between locations that were predicted to be spawning by the logistic regression model where spawning actually occurred and locations that were predicted to be spawning where spawning did not occur. However, the resulting sequential logistic regression model that incorporated the dynamic variables did not provide significant improvement in the percentage of errors for areas predicted to be spawning; the model’s overprediction errors still ranged from 63% to 78%. We suggest that while flow fluctuation may affect spawning habitat and individual fish behavior, the high correlation between time-averaged velocities and the proportion of hourly velocities that fell within the most favorable range negated any improvements in model predictions.},
doi = {10.1577/M07-074.1},
journal = {North American Journal of Fisheries Management, 28(6):1894-1910},
number = 6,
volume = 28,
place = {United States},
year = 2008,
month =
}
  • We improved our predictions of fall chinook salmon (Oncorhynchus tshawytscha) habitat use by analyzing spawning habitat at the spatial scale of redd clusters. Spatial point pattern analyses indicated that redd clusters in the Hanford Reach, Columbia River, were consistent in their location from 1994 to 1995. Redd densities were 16.1 and 8.9 redds?ha-1 in 1994 and 1995, respectively, and individual redds within clusters were usually less than 30 m apart. Pattern analysis also showed strong evidence that redds were uniformly distributed within the clusters where inter-redd distances ranged from 2 to 5 m. Redd clusters were found to occur predominantlymore » where water velocity was between 1.4 to 2 m?s-1, water depth was 2 to 4 m, and lateral slope of the riverbed was less than 4%. This habitat use represented a narrower range of use than previously reported for adult fall chinook salmon. Logistic regression analysis determined that water velocity and lateral slope were the most significant predictors of redd cluster location over a range of river discharges. Over-estimates of available spawning habitat lead to non-achievable goals for protecting and restoring critical salmonid habitat. Better predictions of spawning habitat may be possible if cluster-specific characteristics are used.« less
  • Chum (Oncorhynchus keta) and fall Chinook (O. tshawytscha) salmon segregate spatially during spawning in the Ives Island side channel of the lower Columbia River downstream from Bonneville Dam. Previous research during one spawning season (2000) suggested that these species selected spawning habitats based on differences in hyporheic temperature and vertical hydraulic gradient (VHG) with the river. In this study, we confirmed the spatial segregation of spawning based on hyporheic characteristics over four years (2001–2004) and examined the effects of load-following operations (power generation to meet short-term electrical demand) at Bonneville Dam on hyporheic function and characteristics. We found that duringmore » the study period, hyporheic temperature and VHG in chum salmon spawning areas were highly variable during periods of load-following operation when river levels fluctuated. In contrast, hyporheic water temperature and VHG within chum spawning areas fluctuated less when river levels were not changing due to load-following operation. Variable temperature and VHG could affect chum and fall Chinook salmon spawning segregation and incubation success by altering the cues each species uses to select redd sites. Alterations in site selection would result in a breakdown in the spatial segregation of spawning between chum and fall Chinook salmon, which would expose earlier spawning fall Chinook eggs to a greater risk of dislodgement from later spawning chum salmon. Additional research will be required to fully assess the effects of load-following operations on the hyporheic environment and spawning and incubation success of chum and fall Chinook salmon downstream from Bonneville Dam.« less
  • Fall chinook salmon (Oncorhynchus tshawytscha) spawned predominantly in areas of the Hanford Reach of the Columbia River where hyporheic water discharged into the river channel. This upwelling water had a dissolved solids content (i.e., specific conductance) indicative of river water and was presumed to have entered highly permeable riverbed substrate at locations upstream of the spawning areas. Hyporheic discharge zones composed of undiluted ground water or areas with little or no upwelling were not used by spawning salmon. Rates of upwelling into spawning areas averaged 1,200 L?m-2?day-1 (95% C.I.= 784 to 1,665 L?m-2?day-1) as compared to approximately 500 L?m-2?day-1 (95%more » C.I.= 303 to 1,159 L?m-2?day-1) in non-spawning areas. Dissolved oxygen content of the hyporheic discharge near salmon spawning areas was about 9 mg?L-1 (+ 0.4 mg?L-1) whereas in non-spawning areas dissolved oxygen values were 7 mg?L-1 (+ 0.9 mg?L-1) or lower. In both cases dissolved oxygen of the river water was higher (11.3+ 0.3 mg?L-1). Physical and chemical gradients between the hyporheic zone and the river may provide cues for adult salmon to locate suitable spawning areas. This information will help fisheries managers to describe the suitability of salmon spawning habitat in large rivers.« less
  • We evaluated substrate quality at two historic fall Chinook salmon (Oncorhynchus tshawytscha) spawning sites in the Snake River, Idaho, USA. The primary objective of this evaluation was to measure sediment permeability within these areas to determine the potential quality of the habitat in the event that anadromous salmonids are reintroduced to the upper Snake River. Riverbed sediments within the two sites in the upper Snake River were sampled using freeze cores and hydraulic slug tests. Sediment grain size distributions at both sites were typical of gravel-bed rivers with the surface layer coarser than the underlying substrate, suggesting the riverbed surfacemore » was armored. Despite the armored nature of the bed, the size of the largest material present on the riverbed surface was well within the size limit of material capable of being excavated by spawning fall Chinook salmon. The percentage of fines was low, suggesting good quality substrate for incubating salmon embryos. Geometric mean particle sizes found in this study compared to a 55% to 80% survival to emergence based on literature values. Hydraulic slug tests showed moderate to high hydraulic conductivity and were comparable to values from current fall Chinook salmon spawning areas in the Hells Canyon Reach of the Snake River and the Hanford Reach of the Columbia River. Predicted estimates of mean egg survival at both sites (48% and 74%) equaled or exceeded estimates from fall Chinook salmon spawning areas in the Hells Canyon Reach and the Hanford Reach.« less
  • Chief Joseph Dam on the Columbia River is the upstream terminus for anadromous fish, due to its lack of fish passage facilities. Management agencies are currently evaluating the feasibility of reintroducing anadromous fish upriver of Chief Joseph Dam. We evaluated the physical characteristics of potential fall chinook salmon (Oncorhynchus tshawytscha) spawning habitat in the upper section of Chief Joseph Reservoir. The objective of this study was to estimate the quantity and location of potential spawning habitat, and secondly to determine the redd capacity of the area based on spawning habitat characteristics. We used a geomorphic approach to first identify specificmore » segments with the highest potential for spawning. The suitability of these segments for spawning was then estimated through the use of empirical physical data and modeled hydraulic data. We estimated 5% (48.7 ha) of the study area contains potentially suitable fall chinook salmon spawning habitat. Potential spawning habitat is primarily limited by water too deep and secondly by water velocities too low, the combination of which results in 20% (9.6 ha) of the potential spawning habitat being characterized as high quality. Estimates of redd capacity within potential spawning habitat range from 207? 1599 redds, based on proportional use of potential habitat and varying amounts of channelbed used by spawning salmon. The results of our study provide fisheries managers significant insight into one component of the complex issue of reintroducing anadromous fish to the Columbia River upstream of Chief Joseph Dam.« less