Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California

Holmquist-Johnson, Cristopher L.; Milhous, Robert T.

doi:10.3133/ofr20101086

Cited by 5 publications

(9 citation statements)

References 3 publications

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“…The present sediment discharge of the Smith River is roughly an order of magnitude smaller than the Klamath River (∼ 3.3 × 109 kg yr −1 vs. 0.4 × 109 kg yr −1 ; Wheatcroft and Sommerfield, 2005;California Beach Restoration Study, 2002), opposite to the trend observed offshore. The present difference might be attributed to modern anthropogenic activity (Holmquist- Johnson and Milhous, 2010), mixing of sources on the abyssal plain, or other causes.…”

Section: Discussionmentioning

confidence: 71%

Spatially limited mud turbidites on the Cascadia margin: segmented earthquake ruptures?

Goldfinger

Morey

Black

et al. 2013

Nat. Hazards Earth Syst. Sci.

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Abstract. A series of 23 thin, mostly mud-silt turbidites are found interspersed between larger, well-dated and regionally correlated paleoseismic sandy turbidites that extend along most of the Cascadia margin, northwestern United States. Investigation of the structure, distribution, and sedimentology of these thin mud-silt units supports the interpretation of these units as turbidites originating on the continental slope. Interpretation of mud turbidites is inhibited by bioturbation and lower response to analytical and imaging techniques; nevertheless most of the 23 interpreted beds exhibit most of the characteristics of coarser turbidites. These characteristics include sharp bases, fining upward sequences, darker color, increased gamma and CT density and magnetic susceptibility relative to the hemipelagic background, sparse microfossils, high lithic content, and evidence of transport from marine sources on the continental slope. New core data from sites south of Rogue Apron indicate that sandy and muddy turbidites may be correlated at least 150 km south to Trinidad Plunge Pool for the period ~ 4800 yr BP to present. Many of the mud turbidites initially described at Rogue Apron coarsen southward, becoming sandy turbidites. High-resolution Chirp seismic profiles reveal that turbidite stratigraphy along the base of the southern Cascadia continental slope is continuous, with little variation for at least 240 km along strike. The Chirp data show that turbidites along the Cascadia base of slope are ubiquitous, and likely not sourced solely from submarine canyon mouths, but may also have been delivered to the proximal abyssal plain as sheet flows from the open continental slope and coalescing local sources. Regional stratigraphy reveals that hemipelagic sedimentation rates and total Holocene turbidite thickness and mass are similar at widely separated sites, yet the total thickness of the Holocene section is greater by a factor of two in southern Cascadia. This difference is primarily due to the presence of the 21 mud and two additional sandy turbidites. We conclude that the Cascadia mud turbidites are ubiquitous along southern Cascadia only, with only one likely example of a correlated turbidite limited to the northern margin. Eight onshore sites including three marsh sites and five lakes include potential seismogenic correlatives of the southern Cascadia turbidites. In all, the onshore sites may have recorded > 80% of the events attributed to plate boundary earthquakes offshore during the period 0–6000 yr ago. Slope stability calculations suggest that earthquakes of Mw = 7.0 or greater should generate ground accelerations sufficient to destabilize open slopes and canyon heads with or without excess pore fluid pressure. Estimates of Mw for segmented ruptures are in the range of 7.4–8.7, exceeding the slope stability criteria for typical slopes by at least a factor of ~ four.

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Section: Discussionmentioning

confidence: 71%

Spatially limited mud turbidites on the Cascadia margin: segmented earthquake ruptures?

Goldfinger

Morey

Black

et al. 2013

Nat. Hazards Earth Syst. Sci.

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“…This study, completed in cooperation with the U.S. Fish and Wildlife Service Arcata Field Office and the National Fish and Wildlife Foundation, builds upon a substantial amount of previous work (Ayres and Associates, 1999;Hardy and Addley, 2001;Holmquist-Johnson and Milhous, 2010;Bureau of Reclamation, 2011). Collectively, these previous studies summarized the history of anthropogenic impacts, discussed the importance of large flows for reworking channel substrates, and proposed channel-maintenance flows necessary to achieve a range of substrate movement states along the main-stem Klamath River below Iron Gate Dam.…”

Section: Study Reachmentioning

confidence: 99%

“…An additional objective is deterrence of vegetation encroachment, which stabilizes the edge of the low-flow channel and may result in channel narrowing and loss of low-velocity rearing habitat for juvenile salmonids. Shea and others (2016) used sediment entrainment analyses from three independent studies (Ayres and Associates, 1999;Holmquist-Johnson and Milhous, 2010;Bureau of Reclamation, 2011) to define a range of flows necessary to achieve several channel substrate movement states (fig. 3).…”

Section: Study Reachmentioning

confidence: 99%

“…The dams associated with the hydroelectric facilities block volitional fish passage and access to 420 miles of cold-water habitat in the upper basin (Department of the Interior and others, 2012). The presence of the dams and operation of the reservoir impoundments altered the flow and sediment transport regimes in the lower basin (Ayres and Associates, 1999;Holmquist-Johnson and Milhous, 2010;Department of the Interior and others, 2012;Shea and others, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Sediment mobility and river corridor assessment for a 140-kilometer segment of the main-stem Klamath River below Iron Gate Dam, California

Curtis¹,

Poitras²,

Bond³

et al. 2021

Open-File Report

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This river corridor assessment documents sediment mobility and river response to flood disturbance along a 140-kilometer segment of the main-stem Klamath River below Iron Gate Dam, California. Field and remote sensing methods were used to assess fundamental indicators of active sediment transport and river response to a combination of natural runoff events and reservoir releases during the study period from 2005 to 2019. Discharge measurements at two gaged sites and bed-material samples at two ungaged sites provided direct and indirect evidence of mobile bed conditions, scour and fill, and surface flushing of fine sediment. Available remotesensing datasets collected in 2005, 2009, 2010, and 2016 were used to determine sediment storage, flood inundation boundaries, and provide indirect evidence of flood-induced scour. These datasets validate channel-maintenance flows defined by Shea and others (2016). During the study period, flows greater than or equal to 6,030 cubic feet per second mobilized the substrate, caused localized scour, and flushed fine sediment from bar surfaces. Flows greater than or equal to 10,400 cubic feet per second stripped vegetation from bars and floodplains and produced deeper scour. Flood disturbance within the study reach is produced by the combined effect of natural flows and reservoir releases, which resulted in mobile bed conditions during the study period. Periodic scour and substrate disturbance are considered by the U.S. Fish and Wildlife Service to be integral for managing diseaseinduced mortality of juvenile and adult salmonids. Substrate conditions conducive to parasites that host infectious diseases, particularly Ceratonova shasta, occur periodically. Additional studies are required to determine whether disease prevalence can be mitigated by well-timed reservoir releases. Study results are useful for interpreting linkages among physical and biological processes and for evaluating the effectiveness of flow management targeted to improve river bed conditions for endangered salmonid populations.The biological opinion (BiOp; National Marine Fisheries Service and U.S. Fish and Wildlife Service, 2013) described the effects of the Klamath Irrigation Project on water availability and critical habitat for federally listed salmonid species and determined minimum flow requirements. The 2013 BiOp also provided a summary of studies (Bartholomew and others, 1997;Stocking and Bartholomew, 2007) that identified Manayunkia speciosa, a freshwater polychaete, as the obligate invertebrate host for Ceratonova shasta (syn Ceratomyxa shasta), a myxosporean parasite, known to cause substantial mortality in juvenile and adult salmonids.

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“…Standing stock of primary producers includes dense beds of filamentous algae and rooted-aquatic plants, such as Cladophora sp., Potamogeton sp., and Elodea sp. Both rooted aquatic plants and filamentous algae create seasonally dense plant and algal patches [53] that are visible from river margins. Primary producer dominance changes longitudinally below the hydroelectric dams, shifting from rooted aquatic plant dominance to filamentous algae dominance downstream.…”

Section: Study Sitesmentioning

confidence: 99%

Application of UAV Imagery to Detect and Quantify Submerged Filamentous Algae and Rooted Macrophytes in a Non-Wadeable River

et al. 2020

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Imagery from unoccupied aerial vehicles (UAVs) is useful for mapping floating and emerged primary producers, as well as single taxa of submerged primary producers in shallow, clear lakes and streams. However, there is little research on the effectiveness of UAV imagery-based detection and quantification of submerged filamentous algae and rooted macrophytes in deeper rivers using a standard red-green-blue (RGB) camera. This study provides a novel application of UAV imagery analysis for monitoring a non-wadeable river, the Klamath River in northern California, USA. River depth and solar angle during flight were analyzed to understand their effects on benthic primary producer detection. A supervised, pixel-based Random Trees classifier was utilized as a detection mechanism to estimate the percent cover of submerged filamentous algae and rooted macrophytes from aerial photos within 32 sites along the river in June and July 2019. In-situ surveys conducted via wading and snorkeling were used to validate these data. Overall accuracy was 82% for all sites and the highest overall accuracy of classified UAV images was associated with solar angles between 47.5 and 58.72° (10:04 a.m. to 11:21 a.m.). Benthic algae were detected at depths of 1.9 m underwater and submerged macrophytes were detected down to 1.2 m (river depth) via the UAV imagery in this relatively clear river (Secchi depth > 2 m). Percent cover reached a maximum of 31% for rooted macrophytes and 39% for filamentous algae within all sites. Macrophytes dominated the upstream reaches, while filamentous algae dominated the downstream reaches closer to the Pacific Ocean. In upcoming years, four proposed dam removals are expected to alter the species composition and abundance of benthic filamentous algae and rooted macrophytes, and aerial imagery provides an effective method to monitor these changes.

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Channel Maintenance and Flushing Flows for the Klamath River Below Iron Gate Dam, California

Cited by 5 publications

References 3 publications

Spatially limited mud turbidites on the Cascadia margin: segmented earthquake ruptures?

Spatially limited mud turbidites on the Cascadia margin: segmented earthquake ruptures?

Sediment mobility and river corridor assessment for a 140-kilometer segment of the main-stem Klamath River below Iron Gate Dam, California

Application of UAV Imagery to Detect and Quantify Submerged Filamentous Algae and Rooted Macrophytes in a Non-Wadeable River

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