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Cited by 5Hydrology and Sediment Transport ProcessesFish Ecology and Management StudiesEcology and biodiversity studies

Shallow-Water Habitat in the Lower Columbia River Estuary: A Highly Altered System

Open access
Templeton, William J., Jay, David A., Diefenderfer, Heida L., Talke, Stefan A.·2024·Estuaries and Coasts
DOI 10.1007/s12237-023-01229-3
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Abstract

Decreases in shallow-water habitat area (SWHA) in the Lower Columbia River and Estuary (LCRE) have adversely affected salmonid populations. We investigate the causes by hindcasting SWHA from 1928 to 2004, system-wide, based on daily higher high water (HHW) and system hypsometry. Physics-based regression models are used to represent HHW along the system as a function of river inflow, tides, and coastal processes, and hypsometry is used to estimate the associated SWHA. Scenario modeling is employed to attribute SWHA losses to levees, flow regulation, diversion, navigational development, and climate-induced hydrologic change, for subsidence scenarios of up to 2 m, and for 0.5 m fill. For zero subsidence, the system-wide annual-average loss of SWHA is 55 ± 5%, or 51 × 10 5 ha/year; levees have caused the largest decrease ($${54}_{-14}^{+5}$$54-14+5%, or ~ 50 × 10 5 ha/year). The loss in SWHA due to operation of the hydropower system is small, but spatially and seasonally variable. During the spring freshet critical to juvenile salmonids, the total SWHA loss was$${63}_{-3}^{+2}$$63-3+2%, with the hydropower system causing losses of 5–16% (depending on subsidence). Climate change and navigation have caused SWHA losses of$${5}_{-5}^{+16}$$5-5+16% and$${4}_{-6}^{+14}$$4-6+14%, respectively, but with high spatial variability; irrigation impacts have been small. Uncertain subsidence causes most of the uncertainty in estimates; the sum of the individual factors exceeds the total loss, because factors interact. Any factor that reduces mean or peak flows (reservoirs, diversion, and climate change) or alters tides and along-channel slope (navigation) becomes more impactful as assumed historical elevations are increased to account for subsidence, while levees matter less.

AI snapshot

Written from the paper’s full text.

TL;DR

The paper hindcasts shallow-water habitat area (SWHA) in the Lower Columbia River and Estuary from 1928–2004 and attributes losses to levees, flow regulation, diversion, navigation, and climate change. It finds a system-wide annual-average SWHA loss of 55 ± 5%, dominated by levees, with subsidence as the largest source of uncertainty.

Key findings

  • System-wide annual-average SWHA loss was 55 ± 5%, or 51 × 10⁵ ha/year; levees caused the largest decrease (54 +5 −14%, or ~50 × 10⁵ ha/year).
  • During the spring freshet critical to juvenile salmonids, total SWHA loss was 63 +2 −3%; hydropower-system (FCRPS) losses were 5–16% depending on subsidence, while the annual FCRPS net effect was 0.02 ± 3 1%.
  • Climate change and navigation caused SWHA losses of 5 +16 −5% and 4 +14 −6%, respectively; irrigation impacts were small (0.4 ± 1%).
  • Subsidence causes most uncertainty; the sum of individual factors exceeds the total loss because factors interact, and as assumed subsidence increases, flow-reducing factors and navigation become more impactful while levees matter less.

Methods

  • Daily SWHA was hindcast for 1928–2004 from rkm21 to rkm234 using higher high water (HHW) regression models (Eq. 1) forced by Columbia and Willamette river flows, coastal upwelling index, nonlinear tide-flow interaction, and datum offset; coefficients were interpolated at 1-km intervals.
  • SWHA was estimated from HHW and reach hypsometry based on the 2010 USACE digital terrain model, applying a 2-m depth limit; scenarios combined connected/isolated topography with naturalized, adjusted, or observed flows, and attribution compared altered versus unaltered conditions for levees, FCRPS, navigation channel, irrigation, and climate change.
  • Data included tide-gauge HHW records, USGS/BPA river flows, NOAA tidal predictions, and coastal upwelling index; robust multiple linear regression was used, with bootstrap resampling (10,000 samples) and 95% confidence interval propagation.

Limitations

  • The paper states that subsidence is poorly known and hypsometric uncertainty is the most important factor affecting SWHA loss estimates; attribution factors are not exhaustive, not completely independent, and were largely evaluated one at a time.
  • The paper states that SWHA is an areal measure, not a quality measure; velocity measurements were lacking; restoration effects after 2004 were not considered; and pre-1928 changes were mostly excluded except for levees.
  • The paper states that the statistical approach relies on assumptions such as channel tide gauges representing floodplain water levels and once-daily inundation being sufficient; it also notes that different SWHA depth limits may change results.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1007/s12237-023-01229-3

Cites

73 of 73 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

10 of 56 cited sources checked · 1 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Reduced friction has increased tidal ranges in the reach between Astoria (rkm25) and Quincy (rkm87) on the order of 5-20%.

    “Reduced friction has increased tidal ranges in the reach between Astoria (rkm25) and Quincy (rkm87) on the order of 5-20% (Helaire et al. 2019;Talke et al. 2020).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Helaire et al. 2019 source
    • cites Talke et al. 2020 source

      Section 3.2 (page unavailable) reports a 5% increase in mean tidal range at Astoria and links increased M2 amplitudes in the lower Columbia River to reduced frictional damping. It does not establish a 5–20% increase in tidal range throughout the specified Astoria–Quincy reach; the broader spatial finding concerns M2 amplitude rather than tidal range. (LLM, conf=0.87)

      Experimental — accuracy not yet measured
  • Premisecitation

    SWHA is important to the survival of juvenile salmonids migrating seaward, because they use this habitat to rest, feed, and undergo smoltification.

    “SWHA is important to the survival of juvenile salmonids migrating seaward, because they use this habitat to rest, feed, and undergo smoltification (Johnson et al. 2015;Roegner et al. 2016;Sather et al. 2016).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Johnson et al. 2015 source
    • cites Roegner et al. 2016 source

      The Discussion (page unavailable) describes shallow estuarine habitat as nursery or refuge habitat for small juvenile salmonids, and the Conclusions (page unavailable) describe shallow wetlands and shorelines as sources of insect prey. These passages support refuge and food benefits, but the paper does not establish that salmonids use this habitat to rest or undergo smoltification, or directly demonstrate a survival benefit from those uses. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites Sather et al. 2016 source
  • Premisecitation

    The FCRPS and, to a lesser extent to date, climate change, have greatly altered the annual runoff hydrograph for the mainstem Columbia and its LCRE tributaries.

    “The FCRPS and, to a lesser extent to date, climate change, have greatly altered the annual runoff hydrograph for the mainstem Columbia and its LCRE tributaries, e.g., Willamette, Lewis, and Cowlitz Rivers (Jay and Naik 2011;Naik andJay 2005, 2011a).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Jay and Naik 2011 source

      The Abstract and §1.1 say human flow manipulation changed the Columbia River’s flow cycle more than climate did, and §6 describes altered freshet flows in the mainstem and Willamette River. The paper does not establish the claimed change in the annual runoff hydrographs of the specifically named Lewis and Cowlitz Rivers, so that extension is unsupported by this source. Page numbers are unavailable in our copy. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites Naik and Jay 2005, 2011a

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Premisecitation

    Historical changes in relative sea level rise are small-about 0.06 m in Astoria since the mid-nineteenth century.

    “Additional climate change effects such as relative sea level rise are not considered, because historical changes have been small-about 0.06 m in Astoria since the mid-nineteenth century (Talke et al. 2020).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Talke et al. 2020 source
  • Interpretationcitation

    The methodology used here should be broadly applicable to evaluation of long-term changes in systems used by migrating salmonids along the West Coast of North America and beyond.

    “The methodology used here should be broadly applicable to evaluation of long-term changes in systems used by migrating salmonids; i.e., along the West Coast of North America and beyond (Bidlack et al. 2021;Bond et al. 2018;Buijse et al. 2002;Opperman et al. 2010).”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Bidlack et al. 2021

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Bond et al. 2018 source

      The Methods overview describes a basin-scale method for estimating Chinook salmon rearing habitat in Columbia River tributaries, and the Discussion compares historical, contemporary, and potential restored side-channel habitat. Those passages support its use to evaluate habitat change in one salmonid system, but do not establish applicability to migrating salmonids broadly along the West Coast or beyond (page numbers unavailable in our copy). (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites Buijse et al. 2002 source

      The available passages contain bibliographic metadata (labeled Abstract, no page) and the paper’s title, but no substantive discussion of the proposed methodology. Searches for migrating salmonids, the West Coast, and applicability to long-term evaluation returned no relevant passage from our copy, so the claim cannot be assessed from it. (LLM, conf=0.74)

      Experimental — accuracy not yet measured
  • May combine two claims. 58
  • Classified as probably not a substantial claim. 18

  • May combine two claims.

    Premisecitation

    Since the nineteenth century, flow changes have increased average wintertime water levels in Astoria (rkm25) by 0.03-0.04 m, and decreased May-July water levels by 0.05-0.15 m.

    “Since the nineteenth century, these flow changes have increased average wintertime water levels in Astoria (rkm25) by 0.03-0.04m, and decreased May-July water levels by 0.05-0.15m (Talke et al. 2020);”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Talke et al. 2020 source

      Section 3.3 (page unavailable) estimates that changed river flow raised Astoria water levels by about 0.03 m in winter and lowered them by nearly 0.15 m in July. Our copy does not state the additional 0.04 m winter or 0.05 m May values, so it does not fully substantiate the claimed ranges; it also presents the changes as estimates. (LLM, conf=0.82)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Maximum spring freshet flows are down 40-45% on average, mostly due to flow regulation and irrigation.

    “Additionally, maximum spring freshet flows are down 40-45% on average, mostly due to flow regulation and irrigation.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Jay and Naik 2011b source

      Section 4 (Historical Changes in Overbank Flow; page unavailable) says flow regulation and irrigation depletion have reduced high-flow days and that regulation and diversion have smoothed spring freshet flows. Section 6 (Climate and Human Influences on Freshet Styles; page unavailable) also says regulation decreases freshet magnitude. The cited passages do not establish the claimed average 40–45% reduction in maximum flows. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites Naik and Jay 2011a, b

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Mean annual flows in the LCRE are 15-17% below pre-1900 levels, primarily due to climate change and water withdrawal for agriculture.

    “Mean annual flows are 15-17% below pre-1900 levels, primarily due to climate change and water withdrawal for agriculture (Jay and Naik 2011b; Naik and Jay 2011a, b).”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Jay and Naik 2011b source

      Section 4 (page unavailable) reports lower historical-to-later average annual virgin flow at The Dalles and discusses irrigation depletion and climate influences on flow. It does not give a 15–17% reduction in mean annual flow relative to pre-1900 levels or attribute that specific reduction primarily to climate change and agricultural withdrawal. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
    • cites Naik and Jay 2011a, b

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Floodplain isolation has resulted in decreases in groundwater levels, soil consolidation, decomposition of organic materials that are no longer replenished, and agricultural activities such as grazing that can further compact the soil.

    “Floodplain isolation has resulted in decreases in groundwater levels, soil consolidation, decomposition of organic materials that are no longer replenished, and agricultural activities such as grazing that can further compact the soil (Cannon 2015;Tornqvist et al. 2008).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Cannon 2015

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Tornqvist et al. 2008 source

      The available copy contains a title about Holocene-strata compaction and bibliographic material, but no substantive passage addressing the effects of floodplain isolation. Searches for groundwater decline, organic-material decomposition, grazing, and soil consolidation found no passage establishing the claimed causal links. (LLM, conf=0.72)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingreasoning

    For naturalized flows, SWHA predominantly occurs during the historical freshet period (May through July), while under observed flow conditions, SWHA is more spread out through the year, particularly toward the winter and since about 1940.

    “For naturalized flows, SWHA predominantly occurs during the historical freshet period (May through July), while under observed flow conditions, SWHA is more spread out through the year, particularly toward the winter and since about 1940.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Findingnone given

    There is likely a much larger but unquantifiable systematic uncertainty in the historical bathymetry and topography.

    “There is likely a much larger but unquantifiable systematic uncertainty in the historical bathymetry and topography.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    With the exception of varying GDR, the net changes are close to or less than 1%, and GDR produces variations of less than 10% for the entire system.

    “With the exception of varying GDR, the net changes are close to or less than 1%, and GDR produces variations of less than 10% for the entire system.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The FCRPS has a positive effect on SWHA during the freshet season in the Upper Tidal River and Energy Minimum, but a negative effect in the Upper Estuary, Lower and Middle Tidal River, and Cascade reaches.

    “The FCRPS has a positive effect on SWHA during the freshet season in the Upper Tidal River and Energy Minimum, but a negative effect in the Upper Estuary, Lower and Middle Tidal River, and Cascade reaches.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For the zero-subsidence scenario on which the analysis is primarily based, the sum of factors is 63%, compared to the total loss of 55%; the authors regard this as support of the single-factor analysis approach employed in this study.

    “For the zero-subsidence scenario on which our analysis is primarily based, the sum of factors is 63%, compared to the total loss of 55%; we regard this as support of the single-factor analysis approach employed in this study.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Any factor that reduces mean or peak flows (reservoirs, diversion, and climate change) or alters tides and along-channel slope (navigation) becomes more impactful as assumed historical elevations are increased to account for subsidence, while levees matter less.

    “Any factor that reduces mean or peak flows (reservoirs, diversion, and climate change) or alters tides and along-channel slope (navigation) becomes more impactful as assumed historical elevations are increased to account for subsidence, while levees matter less.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.
    • The authors state this as an assumption: The historical floodplain was higher (subsidence scenarios) or lower (fill scenario) than the present floodplain described by the DTM.

  • May combine two claims.

    Findingreasoning

    The sum of the individual factors exceeds the total loss, because factors interact.

    “the sum of the individual factors exceeds the total loss, because factors interact.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

  • May combine two claims.

    Findingown data

    The sum of the individual factors is larger, on an annual average basis, than the total loss, because factors overlap and interact.

    “Finally, Table 8 shows that the sum of the individual factors is larger, on an annual average basis, than the total loss, because factors overlap and interact.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The lower three Reaches analyzed (the Energy Minimum through Lower Tidal River) all see decreases of 20% or more in SWHA for all flow conditions, whereas the more landward reaches are more variable in their responses; for example, decreased freshet flows have increased SWHA in the Middle and Upper Tidal River during high flow conditions.

    “The lower three Reaches analyzed (the Energy Minimum through Lower Tidal River) all see decreases of 20% or more in SWHA for all flow conditions, whereas the more landward reaches are more variable in their responses; for example, decreased freshet flows have increased SWHA in the Middle and Upper Tidal River during high flow conditions (Table 6).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Findingnone given

    There is no objective means to determine which subsidence or infill/uplift scenario, or combination thereof, is most likely.

    “However, there is no objective means to determine which subsidence or infill/uplift scenario, or combination thereof, is most likely, so we assume zero subsidence for the attribution analysis (Fig. 10).”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Zero subsidence of wetlands behind levees is assumed for the attribution analysis.

  • May combine two claims.

    Findingown data

    SWHA increases as the LiDAR-based bathymetry is raised; the largest increase for historical SWHA in ATP1 occurs by assuming that bathymetry was historically 2 m higher.

    “SWHA increases as the LiDAR-based bathymetry is raised; the largest increase for historical SWHA in ATP1 occurs by assuming that bathymetry was historically 2 m higher (effectively, this assumes that 2 m of subsidence occurred between ATP1 and ATP3).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingnone given

    More realistic subsidence scenarios of 0.5 to 1 m subsidence result in freshet season and annual changes that do not exceed 30% and 60%, respectively.

    “More realistic subsidence scenarios of 0.5 to 1 m subsidence result in freshet season and annual changes that do not exceed 30% and 60%, respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    With a general flattening of the flow hydrograph from the earliest time period (ATP1, starting in 1928) to ATP3, modern high flows behave more like historical average flows; this can increase or decrease SWHA, but net changes due to the FCRPS are small compared to those caused by the levee system and development of the floodplain through levee construction and land conversion.

    “With a general flattening of the flow hydrograph from the earliest time period (ATP1, starting in 1928) to ATP3, modern high flows behave more like historical average flows; this can increase or decrease SWHA, but net changes due to the FCRPS are small compared to those caused by the levee system and development of the floodplain through levee construction and land conversion.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The Middle Tidal River stands out for having SWHA losses for all three of the major factors (levees, climate change, and the FNC) in all seasons, while the Lower Tidal River has losses due to all three during freshet season.

    “The Middle Tidal River stands out for having SWHA losses for all three of the major factors (levees, climate change, and the FNC) in all seasons, while the Lower Tidal River has losses due to all three during freshet season (Fig. 10).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The net effect of climate change is an SWHA loss of 5±16/5%, which is a symptom of decreased peak flows leading to large decreases in SWHA in the river-dominated reaches.

    “The net effect is an SWHA loss of 5± 16 5 %, which is a symptom of decreased peak flows leading to large decreases in SWHA in the river-dominated reaches.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    The most uncertain inputs in the model are bathymetry/topography values (hypsometry), irrigation withdrawal, and routed flows.

    “The most uncertain inputs are bathymetry/topography values (collectively, the hypsometry), irrigation withdrawal, and routed flows.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Accounting for subsidence and infill of leveed areas alters estimated ATP1 SWHA for varying levels of land subsidence and introduces systematic uncertainties into results that are larger than statistical uncertainties for some factors and seasons.

    “Accounting for subsidence and infill of leveed areas alters estimated ATP1 SWHA for varying levels of land subsidence (Fig. 11) and introduces systematic uncertainties into results that are larger than statistical uncertainties for some factors and seasons.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    The results of this study diverge considerably from those of KJ2003a,b: the FCRPS is found here to be a rather small factor in SWHA reduction on an annual average basis, whereas it was a much larger factor in KJ2003a,b.

    “The results of this study diverge considerably from those of KJ2003a,b, in that the FCRPS is found here to be a rather small factor in SWHA reduction on an annual average basis, whereas it was a much larger factor in KJ2003a,b.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites KJ2003a,b

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Findingown data

    Navigation has caused SWHA losses of 4 +14 -6 %, but with high spatial variability.

    “Climate change and navigation have caused SWHA losses of 5 +16 -5 % and 4 +14 -6 %, respectively, but with high spatial variability; irrigation impacts have been small.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

  • May combine two claims.

    Findingnone given

    The tidal river regions that are strongly forced by river flow exhibit the largest change in water level variability over time; however, the corresponding loss in SWHA depends also on hypsometry, complicating the relationship between altered water level variance and SWHA.

    “The tidal river regions that are strongly forced by river flow exhibit the largest change in water level variability over time; however, the corresponding loss in SWHA depends also on hypsometry, complicating the relationship between altered water level variance and SWHA.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    While the various components of the total loss can be estimated by individual attribution factor, factors interact or overlap, so that the total loss is not equal to the sum of the individual losses by factor, contributing to the overall uncertainty level.

    “While the various components of the total loss can be estimated by individual attribution factor (levees, FCRPS, FNC, irrigation, and climate change), factors interact or overlap, so that the total loss is not equal to the sum of the individual losses by factor, contributing to the overall uncertainty level.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Although FCRPS impacts on SWHA are smaller than those of levees, relative losses are measurable in four of six reaches during the freshet season, when climate change, irrigation diversion and hydropower management work in concert to decrease flows.

    “Although FCRPS impacts on SWHA are smaller than those of levees, relative losses are measurable in four of six reaches during the freshet season (Fig. 10A), when climate change, irrigation diversion and hydropower management work in concert to decrease flows.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    Irrigation has minimal impact on SWHA integrated across all reaches and seasons (0.4 ± 1%) but causes minor decreases in SWHA in several reaches during the freshet season.

    “Irrigation has minimal impact on SWHA integrated across all reaches and seasons (0.4 ± 1%) but causes minor decreases in SWHA in several reaches during the freshet season.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    When FCRPS effects are evaluated with the levees in place, the loss of SWHA increases by 112% (17 × 10^3 to 35 × 10^3 ha/year) in the Upper Estuary Reach and the gain of SWHA in the Middle Tidal Reach increases by 247% (9 × 10^3 ha/year of loss to 13 × 10^3 ha/year of gain).

    “We see an increase in the loss of SWHA of 112% (17 × 10 3 to 35 × 10 3 ha/year) in the Upper Estuary Reach and a 247% increase (9 × 10 3 ha/year of loss to 13 × 10 3 ha/year of gain) in the gain of SWHA in the Middle Tidal Reach, respectively, when FCRPS effects are evaluated with the levees in place (Table S8 in the Supplement).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The levee system has produced the largest relative and absolute impacts on changes in SWHA in the system, with annual average losses of 24 × 10^5 ha/year in the Upper Estuary Reach and 25 × 10^5 ha/year collectively between the Energy Minimum, Lower Tidal, and Middle reaches.

    “The levee system has produced the largest relative and absolute impacts on changes in SWHA in the system, with annual average losses of 24 × 10 5 ha/year in the Upper Estuary Reach and 25 × 10 5 ha/year collectively between the Energy Minimum, Lower Tidal, and Middle reaches, all reaches that have been leveed extensively (Fig. 10).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The loss in SWHA due to operation of the hydropower system is small, but spatially and seasonally variable.

    “The loss in SWHA due to operation of the hydropower system is small, but spatially and seasonally variable.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

  • May combine two claims.

    Findingown data

    SWHA is highly sensitive to assumed flow conditions and is strongly affected by flow management.

    “SWHA is highly sensitive to assumed flow conditions and is strongly affected by flow management, so we revisited the scenarios considered by KJ2003a,b by examining all four combinations of naturalized vs. observed flows, and isolated topography vs. connected topography (Fig. 6).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Spatially, the zero-subsidence scenario suggests SWHA loss of 59-76% in the Upper Estuary and lower Tidal River, depending on season; both reaches have large amounts of SWHA.

    “Spatially, the zero-subsidence scenario suggests SWHA loss of 59-76% in the Upper Estuary and lower Tidal River, depending on season; both reaches have large amounts of SWHA.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Freshet season SWHA loss ranges narrowly from 60 to 63% over the subsidence scenarios, but FCRPS total losses range from ~5 to 16%, and FNC and climate total losses also reach ~15% in the 1 m subsidence scenario.

    “Freshet season SWHA loss ranges narrowly from 60 to 63% over the subsidence scenarios, but FCRPS total losses range from ~ 5 to 16%, and FNC and climate total losses also reach ~ 15% in the 1 m subsidence scenario.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The net change in aggregate total SWHA for each reach between historical and modern conditions for the chosen events is typically a loss, with minor exceptions during low and average flows in the Cascade Reach, and under high-flow conditions in the Middle Tidal and Upper Tidal Reaches.

    “The net change in aggregate total SWHA for each reach between historical and modern conditions for the chosen events is typically a loss (Table 6), with minor exceptions during low and average flows in the Cascade Reach, and under high-flow conditions in the Middle Tidal and Upper Tidal Reaches.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The most noticeable increase in SWHA caused by navigational development (the FNC) is seen in the Upper Estuary, while climate change impacts are strongest in the Lower and Middle Tidal River and Cascade Reaches.

    “The most noticeable increase in SWHA caused by navigational development (the FNC) is seen in the Upper Estuary, while climate change impacts are strongest in the Lower and Middle Tidal River and Cascade Reaches (Fig. 10).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    SWHA for isolated topography for both naturalized and observed flows is substantially lower than for connected topography; the levee system has the largest impact on the loss of SWHA in the system.

    “SWHA for isolated topography for both naturalized and observed flows is substantially lower than for connected topography; the levee system has the largest impact on the loss of SWHA in the system (Fig. 6).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    During the spring freshet critical to juvenile salmonids, the total SWHA loss was 63 +2 -3 %, with the hydropower system causing losses of 5-16% (depending on subsidence).

    “During the spring freshet critical to juvenile salmonids, the total SWHA loss was 63 +2 -3 %, with the hydropower system causing losses of 5-16% (depending on subsidence).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

  • May combine two claims.

    Findingown data

    The difference in SWHA between connected and isolated conditions is the loss of potential SWHA due to levees; this loss is concentrated in the Upper Estuary, Lower Tidal River, and Middle Tidal River reaches.

    “The difference in SWHA between connected and isolated conditions (Fig. 3, leveed SWHA-un-leveed SWHA) is the loss of potential SWHA due to levees; this loss is concentrated in the Upper Estuary, Lower Tidal River, and Middle Tidal River reaches.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

  • May combine two claims.

    Findingown data

    The Upper Estuary Reach has the largest amount of SWHA (about 10,000 ha), followed by the Middle Tidal River Reach (~8000 ha), and the Lower Tidal River and Energy Minimum Reaches (both with about ~5000 ha).

    “The Upper Estuary Reach has the largest amount of SWHA (about 10,000 ha), followed by the Middle Tidal River Reach (~ 8000 ha), and the Lower Tidal River and Energy Minimum Reaches (both with about ~ 5000 ha).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Overall, correcting for subsidence increases estimated ATP1 SWHA, and the changes would be large in some areas.

    “Overall, these results suggest that correcting for subsidence increases estimated ATP1 SWHA, and that the changes would be large in some areas.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The largest absolute decreases in SWHA attributable to levees occur in the Upper Estuary and Lower and Middle Tidal Rivers, though substantial losses also occur in the Energy Minimum.

    “The largest absolute decreases in SWHA attributable to levees occur in the Upper Estuary and Lower and Middle Tidal Rivers, though substantial losses also occur in the Energy Minimum. (Fig. 10B).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For zero subsidence, the system-wide annual-average loss of SWHA is 55 ± 5%, or 51 × 10 5 ha/year.

    “For zero subsidence, the system-wide annual-average loss of SWHA is 55 ± 5%, or 51 × 10 5 ha/year;”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.
    • The authors state this as an assumption: Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.
    • The authors state this as an assumption: The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.
    • The authors state this as an assumption: Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.
    • The authors state this as an assumption: Once-daily inundation is sufficient to render a wetland functionally useful as habitat.
    • The authors state this as an assumption: Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

  • May combine two claims.

    Findingown data

    A +10% perturbation in GDR changes total mean annual SWHA by +7.3%, and a -10% perturbation changes it by -9.8%.

    “| | GDR | + 7.3/ -9.8 | |”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    A +10% perturbation in CUI changes total mean annual SWHA by +0.1%, and a -10% perturbation changes it by -0.1%.

    “| | CUI | + 0.1/ -0.1 | |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The difference in total SWHA between ATP3 and ATP2 under high flow was 0.3 ×10^3 ha.

    “| | High | 0.0 | -0.9 | -0.5 | 1.7 | 0.1 | 0.0 | 0.3 |”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    A +10% perturbation in flow changes total mean annual SWHA by +0.9%, and a -10% perturbation changes it by -1.2%.

    “| Total | Flow | + 0.9/ -1.2 | |”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    SWHA for juvenile salmon in tidal rivers and estuaries has been defined as the area inundated to a depth between 0.1 and 2 m with a velocity < 0.3 ms -1.

    “SWHA for juvenile salmon in tidal rivers and estuaries has been defined as the area inundated to a depth between 0.1 and 2 m with a velocity < 0.3 ms -1 (Bottom et al. 2005).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bottom et al. 2005

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Since the 1870s, herbaceous wetland area decreased from 35,466 to 11,381 acres (68%), while forested and shrubscrub decreased from 39,439 to 12,289 acres (69%).

    “Since the 1870s, herbaceous wetland area decreased from 35,466 to 11,381 acres (68%), while forested and shrubscrub decreased from 39,439 to 12,289 acres (69%; Marcoe and Pilson 2017).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Marcoe and Pilson 2017 source

  • May combine two claims.

    Premisecitation

    A large fraction of potential SWHA in the LCRE has been lost since the 1800s, and this loss has been implicated in the decline of threatened and endangered populations.

    “A large fraction of potential SWHA in the LCRE has been lost since the 1800s, and this has been implicated in the decline of threatened and endangered populations (Bottom et al. 2005).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bottom et al. 2005

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    SWHA is a function of spatially and temporally varying water depth and velocity.

    “Consequently, SWHA is a function of spatially and temporally varying water depth and velocity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The Federal Navigation Channel has straightened and approximately doubled the thalweg depth of the system, decreasing frictional effects and reducing mean water levels, though pile dikes introduce friction and prevent an even greater decrease in water levels.

    “Compared to the nineteenth century conditions, the FNC has straightened and approximately doubled the thalweg depth of the system, decreasing frictional effects and reducing mean water levels, though pile dikes introduce friction and prevent an even greater decrease in water levels (Helaire et al. 2019(Helaire et al. , 2020;;Jay et al. 2011).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Helaire et al. 2019 source
    • cites Jay et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Overall, lower low water levels have decreased more than higher high water levels have increased, reducing the mean water level.

    “Overall, lower low water (LLW) levels have decreased more than HHW levels have increased, reducing the mean water level (Helaire et al. 2019;Jay et al. 2011).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Helaire et al. 2019 source
    • cites Jay et al. 2011

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisereasoning

    During high-flow periods, there is very little difference in the tidal river between LLW, mean water level (MWL), and HHW in the tidal river landward of Quincy at rkm87, because tidal ranges are small under these conditions.

    “During high-flow periods, there is very little difference in the tidal river between LLW, mean water level (MWL), and HHW in the tidal river landward of Quincy at rkm87, because tidal ranges are small under these conditions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    These higher floodplain elevations were reached by historic floods (1933 and 1894); modern floods do not reach those elevations.

    “These higher floodplain elevations were reached by historic floods (1933 and 1894 arrows); modern floods do not reach those elevations (see also Helaire et al. 2019).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Helaire et al. 2019 source

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Study design and conductnone given

    As a qualitative tool for evaluating historical change, this approach is useful for all flow conditions.

    “As a qualitative tool for evaluating historical change, this approach is useful for all flow conditions.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    SWHA is strictly an areal measure, not a measure of quality; thus, SWHA may have different utility in different habitats, different seasons, and different eras.

    “However, SWHA is strictly an areal measure, not a measure of quality; thus, SWHA may have different utility in different habitats, different seasons, and different eras.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    This study did not measure whether the lower elevation spring SWHA now available has the same quality as the higher elevation SWHA historically available when spring flows were much higher and dikes absent.

    “SWHA is a measure of habitat area, not quality, and this study did not measure whether the lower elevation spring SWHA now available has the same quality as the higher elevation SWHA historically available, when spring flows were much higher and dikes absent.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Most LCRE levees were constructed between the 1880s and 1930s, so were largely in place during ATP1.

    “We note that most LCRE levees were constructed between the 1880s and 1930s, so were largely in place during ATP1.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Uncertainty limits on the estimates consider both model-parameter and hypsometric sensitivity.

    “Uncertainty limits on these estimates consider both model-parameter and hypsometric sensitivity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Although most of the LCRE upstream of Astoria (rkm 25) has likely subsided, some along-channel and urban parts of the floodplain have been filled.

    “Although most of the LCRE upstream of Astoria (rkm 25) has likely subsided, some along-channel and urban parts of the floodplain have been filled.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Simenstad et al. 2011 source
    • cites Zheng et al. 2014

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationcitation

    There is considerable redundancy in the system, in that both levees and flow regulation/diversion reduce freshet season SWHA, an expected feature of a system engineered in part for floodcontrol in the LCRE.

    “However, as noted by KJ2003a,b, there is considerable redundancy in the system, in that both levees and flow regulation/diversion reduce freshet season SWHA, an expected feature of a system engineered in part for floodcontrol in the LCRE.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites KJ2003a,b

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Subsidence, poorly known in this system, will emerge as the most important factor driving uncertainties in SWHA losses and their attribution.

    “Finally, subsidence, poorly known in this system, will emerge as the most important factor driving uncertainties in SWHA losses and their attribution.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Given the LCRE subsidence values discussed above, the 0, 0.5, and 1 m subsidence scenarios encompass a realistic range; the two extreme scenarios (0.5 m fill and 2 m subsidence) are presented to allow understanding trends with respect to hypsometric change.

    “Given the LCRE subsidence values discussed above, we consider that the 0, 0.5, and 1 m subsidence scenarios encompass a realistic range; the two extreme scenarios (0.5 m fill and 2 m subsidence) are presented to allow understanding trends with respect to hypsometric change.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Alteration of the flow cycle from the 1930s to the 1970s was the primary reason for the shift of SWHA away from the freshet, but this shift also reflects warmer winters and earlier snowpack melt.

    “Alteration of the flow cycle from the 1930s to the 1970s was the primary reason for the shift of SWHA away from the freshet, but this shift also reflects warmer winters and earlier snowpack melt.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Sea-level rise effects on water level decrease in the upstream direction, particularly during high river flow conditions, and MWL in the tidal river has actually decreased since 1900 due to navigational improvements and flow reductions.

    “Moreover, sea-level rise effects on water level decrease in the upstream direction, particularly during high river flow conditions (Helaire et al. 2020), and MWL in the tidal river has actually decreased since 1900 due to navigational improvements and flow reductions.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Helaire et al. 2020 source

  • May combine two claims.

    Interpretationreasoning

    Applying the LiDAR correction factor, the likely median subsidence is ~0.5-0.6 m, not all of which has occurred since 1928.

    “Applying the LiDAR correction factor, the likely median subsidence is ~ 0.5-0.6 m, not all of which has occurred since 1928.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationnone given

    Although hypsometric effects and hydrodynamic change are individual to each system, our method is potentially useful elsewhere where historical water level datasets are available or recoverable for use in mapping changes in SWHA.

    “Although hypsometric effects and hydrodynamic change are individual to each system, our method is potentially useful elsewhere where historical water level datasets are available or recoverable for use in mapping changes in SWHA.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Different depth limits may change results.

    “A primary factor is the definitional requirement per Bottom et al. (2005) that the water level of SWHA not exceed 2 m; different depth limits may change results.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The supply of spatially and temporally comprehensive water level datasets in the system is a limitation.

    “While the supply of spatially and temporally comprehensive water level datasets in the system is a limitation, this is true of any statistical or numerical approach used in a study on a centennial basis and spanning hundreds of kilometers.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Examples of anthropogenically altered systems with secular shifts include the Hudson River and Saint Johns River.

    “Examples include the Hudson River (Ralston et al. 2019) and Saint Johns River (Talke et al. 2021).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Ralston et al. 2019

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Talke et al. 2021 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Without recreating KJ2003a,b's analysis, we are unable to quantify the differences in results due to hypsometry.

    “Without recreating their analysis, we are unable to quantify the differences in results due to hypsometry, but our analysis of subsidence scenarios suggests that hypsometric uncertainty strongly impacts estimates of SWHA loss.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    A primary factor constraining our conclusions is the definitional requirement per Bottom et al. (2005) that the water level of SWHA not exceed 2 m.

    “A primary factor is the definitional requirement per Bottom et al. (2005) that the water level of SWHA not exceed 2 m; different depth limits may change results.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Bottom et al. (2005)

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Study design and conductown data

    MTP3 has a local maximum at rkm-87 due to a known data quality issue, but is otherwise less than 0.22 m up to rkm-170.

    “RMSE for MTP2 increases upstream, while MTP3 has a local maximum at rkm-87 due to a known data quality issue, but is otherwise < 0.22 m up to rkm-170.”
    Quote in the paperNot a substantial claim
73 of 73

  • The authors state this as an assumption.

    Entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role.

    “(1) entrance tidal range (from Astoria or Hammond) and river flow are the primary drivers of tidal-fluvial water levels, with other variables playing a secondary role”

  • The authors state this as an assumption.

    Tide gauges at channel locations provide reasonable estimates of water levels over the floodplain.

    “(2) tide gauges at channel locations provide reasonable estimates of water levels over the floodplain”

  • The authors state this as an assumption.

    The water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic.

    “(3) the water surface slope across the floodplain is smallest at HHW, making HHW the most useful water level statistic”

  • The authors state this as an assumption.

    Time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation.

    “(4) time lags in inundation and slopes across the floodplain are irrelevant for SWHA estimation”

  • The authors state this as an assumption.

    Once-daily inundation is sufficient to render a wetland functionally useful as habitat.

    “(5) once-daily inundation is sufficient to render a wetland functionally useful as habitat”

  • The authors state this as an assumption.

    Tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.

    “(6) tidal properties and water surface-slope vary slowly in space, so that the spatial interpolation of the coefficients is valid.”

  • The authors state this as an assumption.

    The historical floodplain was higher (subsidence scenarios) or lower (fill scenario) than the present floodplain described by the DTM.

    “The underlying assumption is that the historical floodplain was higher (the subsidence scenarios) or lower (the fill scenario) than the present floodplain described by the DTM.”

  • The authors state this as an assumption.

    The unaltered system has connected topography, no upstream irrigation diversion, no FCRPS, and no FNC (i.e., unaltered tides and mean water level).

    “For our purposes, the unaltered system assumes connected topography, no upstream irrigation diversion, no FCRPS, and no FNC (i.e., unaltered tides and mean water level); SWHA for the unaltered system is the unaltered SWHA.”

  • The authors state this as an assumption.

    Zero subsidence of wetlands behind levees is assumed for the attribution analysis.

    “The above estimates assume zero subsidence of wetlands behind levees.”
    “we assume zero subsidence for the attribution analysis (Fig. 10).”

  • The authors state this as an assumption.

    2 m of subsidence is an upper bound on average subsidence.

    “assuming that 2 m of subsidence is an upper bound on average subsidence.”

  • The authors state this as an assumption.

    Leveed areas are never SWHA, even when flooded.

    “We assume that leveed areas are never SWHA, even when flooded.”

  • The paper relies on this without support.

    The freshet season is the season when SWHA use by juvenile salmonids is greatest.

    “These freshet season losses are particularly important, because this is the season when SWHA use by juvenile salmonids is greatest.”
12 of 12

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Key takeaway reverses the stated effect of subsidence correction

    Major

    The key takeaway says that using modern elevations without a subsidence correction overestimates historical SWHA. Elsewhere, the paper says correcting for subsidence increases estimated historical SWHA, so omitting the correction would underestimate it.

  • Attribution-period dates disagree between the definition and Figure 7

    Minor

    The defined ATP1 ends in 1945 and ATP3 begins in 1975, whereas Figure 7 labels ATP1 as ending in 1946 and ATP3 as beginning in 1976. The definition also places 1975 in both ATP2 and ATP3.

  • ATP1 low-flow reach values do not add to the reported total

    Minor

    The six reach values sum to 36.9, not the reported 28.7 (in units of 103 ha). The Energy Minimum value of 11 is also inconsistent with the table's reported ATP3-ATP1 change of −0.6 for that reach.

    Reported 28.7 · recomputed 36.9

  • Table 7 labels irrigation perturbations as 10% rather than 50%

    Minor

    The methods specify a ±50% perturbation for irrigation withdrawals, but Table 7's heading describes its predictor-variable results as arising from ±10% perturbations.

4 of 4

Cited works that were retracted

Works this paper cites that were later retracted, from the retraction notices publishers deposit. Major when the notice came out before this paper was published.

  • Cites a retracted work: 10.2307/1352326

    Info

    The cited work was retracted; the date of the notice is not on record.

    Cited work 10.2307/1352326 · retraction date not known · this paper published 2023-09-26

1 of 1

Cites

1 retracted

Flagged first, then by citations

Research works printed but not linked: 3

  1. Borde, A.B.,H.L. Diefenderfer, S.A. Zimmerman, V.I. Cullinan, and R.M. Thom. 2020. Ecohydrology of wetland plant communities along an estuarine to tidal river gradient. Ecosphere 11(9). https://doi.org/10.1002/ecs2.v11.9 · DOI
  2. Hughes, R.M., J.N. Rinne, and B. Calamusso. 2005. Historical changes in large river fish assemblages of the Americas: A synthesis. American Fisheries Society Symposium. American Fisheries Society, Bethesda, MD 45: 603–612.
  3. Thomas, D.W. and  S.J. Bell. 1983. Changes in Columbia River estuary habitat types over the past century (Vol. 51). Astoria, Oregon: Columbia River Estuary Data Development Program.

Cited by

Sorted by citations

Related

Authors
Templeton, W. J., Jay, D. A., Diefenderfer, H. L., & Talke, S. A.
Affiliations
  • Portland State University (US)
  • Pacific Northwest National Laboratory (US)
  • California Polytechnic State University (US)
Corresponding author
Templeton, William J.
ORCID
Venue
Estuaries and Coasts
Publisher
Springer Science and Business Media LLC
Published
2023-09-26
Volume
47
Issue
1
Pages
91-116
ISSN
  • 1559-2723 (ISSN-L)
  • 1559-2731
DOI
10.1007/s12237-023-01229-3
OpenAlex
W4387048827
Cited by
5
References
68
Citations by year
2026: 2 · 2025: 1 · 2024: 2
FWCI
0.79
Type
journal article
Language
en
Open access
Licence
Locations
  • Estuaries and Coasts (publishedVersion, cc-by)
  • PDXScholar (Portland State University) (submittedVersion, cc-by)
  • OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (submittedVersion)
Funders
Bonneville Power Administration (2002-077-00)
Topics
  • Physical Sciences › Environmental Science › Ecology › Hydrology and Sediment Transport Processes
  • Physical Sciences › Environmental Science › Nature and Landscape Conservation › Fish Ecology and Management Studies
  • Physical Sciences › Environmental Science › Ecology › Ecology and biodiversity studies
Keywords
shallow-water habitats, habitat loss, levees, hydropower regulation, spring freshet, juvenile salmonids, tidal flooding, coastal subsidence, navigation impacts, irrigation, climate change

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-27.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-27.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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