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• 21. [Article] Effects of Selective Logging and Roads on Instream Fine Sediments and Macroinvertebrate Assemblages in the Clackamas Basin, Oregon

  Logging and associated skid trails, haul routes, and roads can have significant impacts on the magnitude and timing of sediments in streams in forested watersheds. Loss of vegetation, soil compaction, ...

  Citation × Citation Citation Abstract Copy Title: Effects of Selective Logging and Roads on Instream Fine Sediments and Macroinvertebrate Assemblages in the Clackamas Basin, Oregon Author: Hood, Paula Elizabeth Year: 2015 Logging and associated skid trails, haul routes, and roads can have significant impacts on the magnitude and timing of sediments in streams in forested watersheds. Loss of vegetation, soil compaction, use of heavy logging equipment, and alteration of natural hydrologic patterns within the watershed can increase landslide rates, create erosion, and generate fine sediments. Selective logging, also called thinning, is a logging practice that leaves some trees within sale units unharvested. The ecological impacts of thinning on stream ecosystems are not fully understood and need further study. My hypothesis was that macroinvertebrate assemblages would be different in streams in non-reference areas that contain recent selective logging compared to streams in reference areas, and in downstream vs. upstream of selective logging units. I also hypothesized that selective logging and high road densities would be associated with increased instream fine sediments. I sampled water quality parameters and macroinvertebrates in three managed and three reference streams in the Clackamas River Basin during the field season of 2013. Turbidity, temperature, dissolved oxygen, conductivity, total dissolved solids (TDS), suspended sediment concentrations (SSC), and flow were sampled at each stream on four occasions during spring through early fall. Macroinvertebrates were sampled once in late summer or early fall. EPA rapid habitat assessments, canopy cover, pebble counts, embeddedness, and slope were also determined. Water quality parameters and macroinvertebrate indices in reference and non-reference sites were compared using t-tests, Welch's tests, or rank based equivalents. Macroinvertebrate assemblage patterns and associated environmental variables were characterized using non-metric multidimensional scaling (NMDS) ordination plots and envfit overlays. Macroinvertebrates had higher abundance and taxa richness in non-reference streams, and indices suggested poorer water quality in non-reference streams. Non-reference streams had a lower percentage of shredders and a higher portion of gatherer-collectors. Associations between land use, fine sediments, and changes in macroinvertebrate metrics and community assemblages were apparent at the reference vs. non-reference scale. It is likely that macroinvertebrates are responding, at least in part, to past logging and high road densities in non-reference streams. Fewer indications were found that recent logging may be affecting water quality and macroinvertebrates. Pearson's correlation coefficients show that the percent of recent logging upstream of study sites was correlated with several measures of fine sediments, suggesting that recent land use may be affecting sediment levels at the subwatershed scale. Stream temperatures increased from upstream to downstream in non-reference sites. Though no continual stream temperature data were collected in this study, the history of continuing temperature standard exceedances in the area suggest that further investigation of how selective logging may be affecting stream temperature and other water quality parameters in the Clackamas Basin is warranted. No other differences in water quality parameters were found from upstream to downstream, possibly because water quality was sufficiently protected, or because signals from land use impacts may be obscured by a several factors, including upstream confounding factors such as roads and past logging, and natural variability. Title: Effects of Selective Logging and Roads on Instream Fine Sediments and Macroinvertebrate Assemblages in the Clackamas Basin, Oregon Author: Hood, Paula Elizabeth Year: 2015 Logging and associated skid trails, haul routes, and roads can have significant impacts on the magnitude and timing of sediments in streams in forested watersheds. Loss of vegetation, soil compaction, use of heavy logging equipment, and alteration of natural hydrologic patterns within the watershed can increase landslide rates, create erosion, and generate fine sediments. Selective logging, also called thinning, is a logging practice that leaves some trees within sale units unharvested. The ecological impacts of thinning on stream ecosystems are not fully understood and need further study. My hypothesis was that macroinvertebrate assemblages would be different in streams in non-reference areas that contain recent selective logging compared to streams in reference areas, and in downstream vs. upstream of selective logging units. I also hypothesized that selective logging and high road densities would be associated with increased instream fine sediments. I sampled water quality parameters and macroinvertebrates in three managed and three reference streams in the Clackamas River Basin during the field season of 2013. Turbidity, temperature, dissolved oxygen, conductivity, total dissolved solids (TDS), suspended sediment concentrations (SSC), and flow were sampled at each stream on four occasions during spring through early fall. Macroinvertebrates were sampled once in late summer or early fall. EPA rapid habitat assessments, canopy cover, pebble counts, embeddedness, and slope were also determined. Water quality parameters and macroinvertebrate indices in reference and non-reference sites were compared using t-tests, Welch's tests, or rank based equivalents. Macroinvertebrate assemblage patterns and associated environmental variables were characterized using non-metric multidimensional scaling (NMDS) ordination plots and envfit overlays. Macroinvertebrates had higher abundance and taxa richness in non-reference streams, and indices suggested poorer water quality in non-reference streams. Non-reference streams had a lower percentage of shredders and a higher portion of gatherer-collectors. Associations between land use, fine sediments, and changes in macroinvertebrate metrics and community assemblages were apparent at the reference vs. non-reference scale. It is likely that macroinvertebrates are responding, at least in part, to past logging and high road densities in non-reference streams. Fewer indications were found that recent logging may be affecting water quality and macroinvertebrates. Pearson's correlation coefficients show that the percent of recent logging upstream of study sites was correlated with several measures of fine sediments, suggesting that recent land use may be affecting sediment levels at the subwatershed scale. Stream temperatures increased from upstream to downstream in non-reference sites. Though no continual stream temperature data were collected in this study, the history of continuing temperature standard exceedances in the area suggest that further investigation of how selective logging may be affecting stream temperature and other water quality parameters in the Clackamas Basin is warranted. No other differences in water quality parameters were found from upstream to downstream, possibly because water quality was sufficiently protected, or because signals from land use impacts may be obscured by a several factors, including upstream confounding factors such as roads and past logging, and natural variability. Close

• 22. [Article] Oxygen Demand Trends, Land Cover Change, and Water Quality Management for an Urbanizing Oregon Watershed

  In-stream aquatic habitat depends on adequate levels of dissolved oxygen. Human alteration of the landscape has an extensive influence on the biogeochemical processes that drive oxygen cycling in streams. ...

  Citation × Citation Citation Abstract Copy Title: Oxygen Demand Trends, Land Cover Change, and Water Quality Management for an Urbanizing Oregon Watershed Author: Boeder, Michael Karl Year: 2006 In-stream aquatic habitat depends on adequate levels of dissolved oxygen. Human alteration of the landscape has an extensive influence on the biogeochemical processes that drive oxygen cycling in streams. Historic datasets allow researchers to track trends in chemical parameters concomitant with urbanization, while land cover change analysis allows researchers to identify linkages between water quality trends and landscape change. Using the Seasonal Kendall's test, I examined water quality trends in oxygen demand variables during the mid-1990s to 2003, for twelve sites in the Rock Creek sub-watershed of the Tualatin River, northwest Oregon. Significant trends occurred in each parameter. Dissolved oxygen (DO (%sat)) increased at five sites. Chemical oxygen demand (COD) decreased at seven sites. Total Kjeldahl nitrogen (TKN) decreased at five sites and increased at one site. Ammonium (NH3-N) decreased at one site and increased at one site. Multiple linear regression indicates that nitrogenous oxygen demand accounts for a significant amount of variance in COD at ten of the twelve sites (adjusted R2values from 0.14 to 0.73). Aerial photo interpretation revealed significant land cover change in agricultural land cover (-8% for the entire basin area) and residential land cover (+10% for the entire basin area). Correlation results between seasonal oxygen demand data and land cover values at multiple scales indicated that: (I) forest cover negatively influences COD at the full sub-basin scale and positively influences NH3-N at local scales, (2) residential land cover positively influences DO (%sat) values at local scales, (3) agricultural land cover does not influence oxygen demand at any land cover assessment scale, ( 4) local topography negatively influences TKN and NH3-N, and (5) urban runoff management infrastructure correlates positively with COD. Study results indicate that, with the exception of forested land, local scale land cover and landscape variables dominate influence on oxygen demand in the Rock Creek basin. Since DO conditions have improved in these streams, watershed management efforts should emphasize local influences in order to continue to maintain stream health. Title: Oxygen Demand Trends, Land Cover Change, and Water Quality Management for an Urbanizing Oregon Watershed Author: Boeder, Michael Karl Year: 2006 In-stream aquatic habitat depends on adequate levels of dissolved oxygen. Human alteration of the landscape has an extensive influence on the biogeochemical processes that drive oxygen cycling in streams. Historic datasets allow researchers to track trends in chemical parameters concomitant with urbanization, while land cover change analysis allows researchers to identify linkages between water quality trends and landscape change. Using the Seasonal Kendall's test, I examined water quality trends in oxygen demand variables during the mid-1990s to 2003, for twelve sites in the Rock Creek sub-watershed of the Tualatin River, northwest Oregon. Significant trends occurred in each parameter. Dissolved oxygen (DO (%sat)) increased at five sites. Chemical oxygen demand (COD) decreased at seven sites. Total Kjeldahl nitrogen (TKN) decreased at five sites and increased at one site. Ammonium (NH3-N) decreased at one site and increased at one site. Multiple linear regression indicates that nitrogenous oxygen demand accounts for a significant amount of variance in COD at ten of the twelve sites (adjusted R2values from 0.14 to 0.73). Aerial photo interpretation revealed significant land cover change in agricultural land cover (-8% for the entire basin area) and residential land cover (+10% for the entire basin area). Correlation results between seasonal oxygen demand data and land cover values at multiple scales indicated that: (I) forest cover negatively influences COD at the full sub-basin scale and positively influences NH3-N at local scales, (2) residential land cover positively influences DO (%sat) values at local scales, (3) agricultural land cover does not influence oxygen demand at any land cover assessment scale, ( 4) local topography negatively influences TKN and NH3-N, and (5) urban runoff management infrastructure correlates positively with COD. Study results indicate that, with the exception of forested land, local scale land cover and landscape variables dominate influence on oxygen demand in the Rock Creek basin. Since DO conditions have improved in these streams, watershed management efforts should emphasize local influences in order to continue to maintain stream health. Close

• 23. [Article] Groundwater-Surface Water Interactions near Mosier, Oregon

  The town of Mosier, Oregon, is located near the east, dry end of the Columbia River Gorge, and the local area is known for cherry orchards that rely heavily on groundwater for irrigation. The CRBG groundwater ...

  Citation × Citation Citation Abstract Copy Title: Groundwater-Surface Water Interactions near Mosier, Oregon Author: Jones, Cullen Brandon Year: 2016 The town of Mosier, Oregon, is located near the east, dry end of the Columbia River Gorge, and the local area is known for cherry orchards that rely heavily on groundwater for irrigation. The CRBG groundwater system in Mosier has experienced groundwater declines of up to 60 meters due to over-pumping and or commingling. Declining groundwater levels have led to concerns over the sustainability of the resource, as it is the principle water source for irrigation and domestic use. Despite numerous previous studies of groundwater flow in CRBG aquifers here and elsewhere in the Columbia River basin, an aspect that has received relatively little attention is the interaction between groundwater and surface waters at locations where interflow zones are intersected by the surface waters. The objective of my research is to investigate how CRBG interflow zone exposures in Mosier Creek may be controlling groundwater elevations in the area. The methods used include: (1) geochemical analysis of well cuttings and detailed geologic mapping along area streams to identify interflow zones of individual CRBG flows, (2) analysis of stream discharge data and groundwater elevation data to confirm exchange of groundwater and surface waters, and (3) collection and analyses of 31 water samples from area wells, streams, and springs, to determine if waters from individual CRBG aquifers can be hydrochemically identified and to further constrain understanding of surface and groundwater interactions. My study confirms that the general elevation of the Pomona Member and Basalt of Lolo interflow zone creek exposure is coincident with the elevation where a change in slope of the decline trend in 2004 is seen in Mosier area well hydrographs. Furthermore, the results of stream discharge data indicated a close connection between drawdown from groundwater pumping during irrigation season and groundwater- surface water interaction. At the time of drawdown in the upper-most CRBG aquifer (Pomona), the stream transitions from gaining to losing water into the groundwater system. Elemental chemistry data indicates the Frenchman Springs Sentinel Gap aquifer waters are the most evolved waters in this study. Stable isotopic data reinforced this determination as the Sentinel Gap waters are the lightest, or most negative, with regard to δD and δ18O. Sentinel Gap samples were more depleted than other aquifer samples by 4.38 to 6.89 0/100 for δD and 0.39 to 0.59 0/100 for δ18O. The results of the general chemistry and isotope data reveal a more evolved chemical signature in lower watershed groundwater versus a less evolved signature for waters from wells located higher up on the Columbia Hills anticline. This was interpreted to be the result of the major structural features in the area providing for a more regional pathway of recharge in lower watershed groundwaters, versus a more local source of recharge for upper watershed groundwaters. There was also a pronounced commingled signature in the elemental ratios of lower watershed aquifer waters. The suspected mechanism of recharge to lower watershed wells is through younger Cascadian deposits upslope from the local watershed. The findings of this study reveal the importance of a detailed understanding of CRBG stratigraphy and its relation to surface waters, especially for other areas within the Yakima Fold Belt or Oregon and Washington. Studies that do not consider the influence that individual CRBG flows can have on groundwater-surface water interactions, and the groundwater system as a whole, run the risk of improperly assessing the groundwater resource for a region. Title: Groundwater-Surface Water Interactions near Mosier, Oregon Author: Jones, Cullen Brandon Year: 2016 The town of Mosier, Oregon, is located near the east, dry end of the Columbia River Gorge, and the local area is known for cherry orchards that rely heavily on groundwater for irrigation. The CRBG groundwater system in Mosier has experienced groundwater declines of up to 60 meters due to over-pumping and or commingling. Declining groundwater levels have led to concerns over the sustainability of the resource, as it is the principle water source for irrigation and domestic use. Despite numerous previous studies of groundwater flow in CRBG aquifers here and elsewhere in the Columbia River basin, an aspect that has received relatively little attention is the interaction between groundwater and surface waters at locations where interflow zones are intersected by the surface waters. The objective of my research is to investigate how CRBG interflow zone exposures in Mosier Creek may be controlling groundwater elevations in the area. The methods used include: (1) geochemical analysis of well cuttings and detailed geologic mapping along area streams to identify interflow zones of individual CRBG flows, (2) analysis of stream discharge data and groundwater elevation data to confirm exchange of groundwater and surface waters, and (3) collection and analyses of 31 water samples from area wells, streams, and springs, to determine if waters from individual CRBG aquifers can be hydrochemically identified and to further constrain understanding of surface and groundwater interactions. My study confirms that the general elevation of the Pomona Member and Basalt of Lolo interflow zone creek exposure is coincident with the elevation where a change in slope of the decline trend in 2004 is seen in Mosier area well hydrographs. Furthermore, the results of stream discharge data indicated a close connection between drawdown from groundwater pumping during irrigation season and groundwater- surface water interaction. At the time of drawdown in the upper-most CRBG aquifer (Pomona), the stream transitions from gaining to losing water into the groundwater system. Elemental chemistry data indicates the Frenchman Springs Sentinel Gap aquifer waters are the most evolved waters in this study. Stable isotopic data reinforced this determination as the Sentinel Gap waters are the lightest, or most negative, with regard to δD and δ18O. Sentinel Gap samples were more depleted than other aquifer samples by 4.38 to 6.89 0/100 for δD and 0.39 to 0.59 0/100 for δ18O. The results of the general chemistry and isotope data reveal a more evolved chemical signature in lower watershed groundwater versus a less evolved signature for waters from wells located higher up on the Columbia Hills anticline. This was interpreted to be the result of the major structural features in the area providing for a more regional pathway of recharge in lower watershed groundwaters, versus a more local source of recharge for upper watershed groundwaters. There was also a pronounced commingled signature in the elemental ratios of lower watershed aquifer waters. The suspected mechanism of recharge to lower watershed wells is through younger Cascadian deposits upslope from the local watershed. The findings of this study reveal the importance of a detailed understanding of CRBG stratigraphy and its relation to surface waters, especially for other areas within the Yakima Fold Belt or Oregon and Washington. Studies that do not consider the influence that individual CRBG flows can have on groundwater-surface water interactions, and the groundwater system as a whole, run the risk of improperly assessing the groundwater resource for a region. Close

• 24. [Article] Riparian Shade Assessment and Restoration Priorities Analysis in the Damascus Urban Growth Boundary Expansion Area

  An important component of progressive urban planning is the protection and restoration of riparian environments, particularly in the Pacific Northwest where increasing stream temperatures threaten the ...

  Citation × Citation Citation Abstract Copy Title: Riparian Shade Assessment and Restoration Priorities Analysis in the Damascus Urban Growth Boundary Expansion Area Author: Leferink, Robin K. Year: 2007 An important component of progressive urban planning is the protection and restoration of riparian environments, particularly in the Pacific Northwest where increasing stream temperatures threaten the survival of endangered salmonids and other cold-water biota. Restoration projects are often led by watershed councils or other grassroots organizations with limited resources, and it is essential that these groups have an efficient and effective approach to determine priority areas where their efforts can be directed to achieve the greatest ecological benefit. The purpose of this project was to quantify existing riparian shade levels and identify priority reaches for shade restoration on Clackamas River basin streams in the Damascus area expansion of the Portland, Oregon urban growth boundary. Additionally, potential errors in the Metro Regional Land Information System (RLIS) Lite geographic information system (GIS) coverage of the area’s streams were identified and corrected where possible. Riparian shade levels were quantified through interpretation of digital aerial photographs using GIS. At the start of the shade analysis six 50 m reaches in the study area were surveyed using a spherical densiometer to calibrate the aerial photo interpretation. Following the analysis, the method accuracy was assessed by comparing GIS-derived shade classes with field data from 25 sites in the study area that were surveyed in 2003. Stream reaches were identified and prioritized for restoration based on riparian shade level, presence or absence of late-summer flow (as determined through field investigations), and GISevaluated stream aspect (i.e. the direction of stream flow). Generally, the headwaters were found to have less shade than the downstream areas and many of the headwater reaches were identified as the highest restoration priority. Of the 60.5 km of streams assessed in the riparian shade analysis, 24.7 km were identified as potential restoration reaches based on shade levels and late-summer flow conditions. These 24.7 km were further broken into five priority ranks, with 4.1 km of stream reaches assigned to the highest shade restoration priority class. Potential errors in the GIS stream coverage were identified in conjunction with the riparian shade assessment. Where possible, these errors were corrected based on the aerial photographs. Although in many cases access was limited, a total of 18 site visits were made to verify stream locations. The results of this watershed-scale restoration priorities analysis are being used by Clackamas River Basin Council and others to guide restoration planning in the new urban area. While focusing on the high priority stream reaches identified, restoration managers will also need to consider reach-scale factors including land use plans, riparian continuity, parcel size, and landowner cooperation in the final selection of restoration sites. The GIS stream layer corrections were provided to Metro and to the City of Damascus for use in their 2007 natural resource inventory. Title: Riparian Shade Assessment and Restoration Priorities Analysis in the Damascus Urban Growth Boundary Expansion Area Author: Leferink, Robin K. Year: 2007 An important component of progressive urban planning is the protection and restoration of riparian environments, particularly in the Pacific Northwest where increasing stream temperatures threaten the survival of endangered salmonids and other cold-water biota. Restoration projects are often led by watershed councils or other grassroots organizations with limited resources, and it is essential that these groups have an efficient and effective approach to determine priority areas where their efforts can be directed to achieve the greatest ecological benefit. The purpose of this project was to quantify existing riparian shade levels and identify priority reaches for shade restoration on Clackamas River basin streams in the Damascus area expansion of the Portland, Oregon urban growth boundary. Additionally, potential errors in the Metro Regional Land Information System (RLIS) Lite geographic information system (GIS) coverage of the area’s streams were identified and corrected where possible. Riparian shade levels were quantified through interpretation of digital aerial photographs using GIS. At the start of the shade analysis six 50 m reaches in the study area were surveyed using a spherical densiometer to calibrate the aerial photo interpretation. Following the analysis, the method accuracy was assessed by comparing GIS-derived shade classes with field data from 25 sites in the study area that were surveyed in 2003. Stream reaches were identified and prioritized for restoration based on riparian shade level, presence or absence of late-summer flow (as determined through field investigations), and GISevaluated stream aspect (i.e. the direction of stream flow). Generally, the headwaters were found to have less shade than the downstream areas and many of the headwater reaches were identified as the highest restoration priority. Of the 60.5 km of streams assessed in the riparian shade analysis, 24.7 km were identified as potential restoration reaches based on shade levels and late-summer flow conditions. These 24.7 km were further broken into five priority ranks, with 4.1 km of stream reaches assigned to the highest shade restoration priority class. Potential errors in the GIS stream coverage were identified in conjunction with the riparian shade assessment. Where possible, these errors were corrected based on the aerial photographs. Although in many cases access was limited, a total of 18 site visits were made to verify stream locations. The results of this watershed-scale restoration priorities analysis are being used by Clackamas River Basin Council and others to guide restoration planning in the new urban area. While focusing on the high priority stream reaches identified, restoration managers will also need to consider reach-scale factors including land use plans, riparian continuity, parcel size, and landowner cooperation in the final selection of restoration sites. The GIS stream layer corrections were provided to Metro and to the City of Damascus for use in their 2007 natural resource inventory. Close

• 25. [Article] The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models

  The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving ...

  Citation × Citation Citation Abstract Copy Title: The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models Author: Mtundu, Nangantani Davies Godfrey Year: 1987 The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving such models is the dependence of hydrologic response on initial soil moisture. The dependence affects the distributions and moments of the hydrological processes being investigated. A stochastic model of soil moisture dynamics is developed in the form of a pair of stochastic differential equations (SDE's) of the Ito type. The sources of stochasticity are linked to the random inputs of rainfall and evapotranspiration (ET). One of the SDE's describes the "surplus" case, in which sufficient infiltration always occurs to allow for moisture depletion by the processes of drainage through and ET out of the root zone. The other SDE represents the "deficit" case, in which lack of adequate moisture leads only to an ET-controlled depletion process. Sample functions and moments of moisture evolution are obtained from the SDE's. From the general model of soil moisture, a specific model of initial soil moisture (the moisture at the beginning of a rainstorm event) is developed and its moments are derived. Furthermore, the probability distribution of initial moisture is postulated to permit the assessment of how initial moisture affects the estimation of hydrologic response. The moisture dynamics model reveals that the stochastic properties of moisture ae sensitive to initial conditions in the watershed only for less permeable soils under the "surplus" state but are practically insensitive to such conditions for more permeable soils. The stochastic properties are also less sensitive to initial conditions for all soil types whenever under the "deficit" state. These results suggest that hydrologic processes, such as precipitation excess and infiltration, depend on initial moisture only in regions where the soils are generally less permeable and where the climate tends to sustain a "wet" environment, whereas in arid or semi-arid regions, such processes would not depend on initial moisture. These conclusions imply that, in arid regions, an effective value of initial moisture such as the mean can be used to estimate the properties of the hydrologic processes, whereas in "wet" environments, more accurate values of the properties must be "weighted" based on the probability distribution of initial soil moisture. Title: The Stochastic Behavior of Soil Moisture and Its Role in Catchment Response Models Author: Mtundu, Nangantani Davies Godfrey Year: 1987 The object of current efforts at investigating catchment response is to derive a physically based stochastic model of the watershed. Recent studies have, however, indicated that a limiting factor in deriving such models is the dependence of hydrologic response on initial soil moisture. The dependence affects the distributions and moments of the hydrological processes being investigated. A stochastic model of soil moisture dynamics is developed in the form of a pair of stochastic differential equations (SDE's) of the Ito type. The sources of stochasticity are linked to the random inputs of rainfall and evapotranspiration (ET). One of the SDE's describes the "surplus" case, in which sufficient infiltration always occurs to allow for moisture depletion by the processes of drainage through and ET out of the root zone. The other SDE represents the "deficit" case, in which lack of adequate moisture leads only to an ET-controlled depletion process. Sample functions and moments of moisture evolution are obtained from the SDE's. From the general model of soil moisture, a specific model of initial soil moisture (the moisture at the beginning of a rainstorm event) is developed and its moments are derived. Furthermore, the probability distribution of initial moisture is postulated to permit the assessment of how initial moisture affects the estimation of hydrologic response. The moisture dynamics model reveals that the stochastic properties of moisture ae sensitive to initial conditions in the watershed only for less permeable soils under the "surplus" state but are practically insensitive to such conditions for more permeable soils. The stochastic properties are also less sensitive to initial conditions for all soil types whenever under the "deficit" state. These results suggest that hydrologic processes, such as precipitation excess and infiltration, depend on initial moisture only in regions where the soils are generally less permeable and where the climate tends to sustain a "wet" environment, whereas in arid or semi-arid regions, such processes would not depend on initial moisture. These conclusions imply that, in arid regions, an effective value of initial moisture such as the mean can be used to estimate the properties of the hydrologic processes, whereas in "wet" environments, more accurate values of the properties must be "weighted" based on the probability distribution of initial soil moisture. Close

• 26. [Article] Landforms along the Lower Columbia River and the Influence of Humans

  River systems, such as the Columbia River in the Pacific Northwest, USA have been influenced by human activities, resulting in changes to the physical processes that drive landform evolution. This work ...

  Citation × Citation Citation Abstract Copy Title: Landforms along the Lower Columbia River and the Influence of Humans Author: Cannon, Charles Matthew Year: 2015 River systems, such as the Columbia River in the Pacific Northwest, USA have been influenced by human activities, resulting in changes to the physical processes that drive landform evolution. This work describes an inventory of landforms along the Columbia River estuary between the Pacific Ocean and Bonneville Dam in Oregon and Washington. Groupings of landforms are assigned to formative process regimes that are used to assess historical changes to floodplain features. The estuary was historically a complex system of channels with a floodplain dominated by extensive tidal wetlands in the lower reaches and backswamp lakes and wetlands in upper reaches. Natural levees flank most channels in the upper reaches, locally including areas of ridge and swale topography and crevasse splays that intrude into backswamps. Other Holocene process regimes affecting floodplain morphology have included volcanogenic deltas, tributary fans, dunes, and landslides. Pre-Holocene landforms are locally prominent and include ancient fluvial deposits and bedrock. Historical changes to streamflow regimes, floodplain isolation by flood-control systems, and direct anthropogenic disturbance have resulted in channel narrowing and limited the amount of floodplain that can be shaped by flowing water. Floodplain isolation has caused relative subsidence of tidal floodplains along much of the lower estuary. Most extant landforms are on trajectories controlled by humans and new landforms are mostly created by humans. Title: Landforms along the Lower Columbia River and the Influence of Humans Author: Cannon, Charles Matthew Year: 2015 River systems, such as the Columbia River in the Pacific Northwest, USA have been influenced by human activities, resulting in changes to the physical processes that drive landform evolution. This work describes an inventory of landforms along the Columbia River estuary between the Pacific Ocean and Bonneville Dam in Oregon and Washington. Groupings of landforms are assigned to formative process regimes that are used to assess historical changes to floodplain features. The estuary was historically a complex system of channels with a floodplain dominated by extensive tidal wetlands in the lower reaches and backswamp lakes and wetlands in upper reaches. Natural levees flank most channels in the upper reaches, locally including areas of ridge and swale topography and crevasse splays that intrude into backswamps. Other Holocene process regimes affecting floodplain morphology have included volcanogenic deltas, tributary fans, dunes, and landslides. Pre-Holocene landforms are locally prominent and include ancient fluvial deposits and bedrock. Historical changes to streamflow regimes, floodplain isolation by flood-control systems, and direct anthropogenic disturbance have resulted in channel narrowing and limited the amount of floodplain that can be shaped by flowing water. Floodplain isolation has caused relative subsidence of tidal floodplains along much of the lower estuary. Most extant landforms are on trajectories controlled by humans and new landforms are mostly created by humans. Close

• 27. [Article] Effects of Tide Gate Replacement on Water Temperature ina Freshwater Slough in the Columbia River Estuary

  Dramatic declines in salmon populations in the Pacific Northwest have brought new attention to the importance of estuarine rearing habitats. Levees and tide gates used to convert estuarine wetlands into ...

  Citation × Citation Citation Abstract Copy Title: Effects of Tide Gate Replacement on Water Temperature ina Freshwater Slough in the Columbia River Estuary Author: Ennis, Sara Year: 2009 Dramatic declines in salmon populations in the Pacific Northwest have brought new attention to the importance of estuarine rearing habitats. Levees and tide gates used to convert estuarine wetlands into farmland have reduced available habitat by more than half of historical levels. Recent efforts to restore estuarine habitats include tide gate replacement, though this method has been poorly studied. As a key indicator of salmon habitat suitability, temperature was used to evaluate the effects of tide gate replacement in a tidally influenced freshwater slough in the Lower Columbia River estuary. Three tide gates in the largest slough on Tenasillahe Island were replaced in 2007 with side-hinged aluminum gates. As managed during the data collection periods, the new tide gates did not allow tidal inflow into the slough. The study employed a Before-After, Control-Impact (BACI) approach, collecting data seasonally two years before and after replacement at the impact site and at the control site, a relatively unaltered slough on nearby Welch Island. Randomized Intervention Analysis and Monte Carlo tests revealed no significant difference in slough water temperatures after tide gate replacement, although minimum temperatures dropped up and downstream of the tide gates. Although the new tide gates did not have a significant effect on water temperature, the lower minimum temperatures may have been caused by a slight increase in tidal circulation. This result suggests that slough temperatures would decrease if the tide gates were managed to increase tidal inflow, and thus improve the quality of salmon rearing habitat. Title: Effects of Tide Gate Replacement on Water Temperature ina Freshwater Slough in the Columbia River Estuary Author: Ennis, Sara Year: 2009 Dramatic declines in salmon populations in the Pacific Northwest have brought new attention to the importance of estuarine rearing habitats. Levees and tide gates used to convert estuarine wetlands into farmland have reduced available habitat by more than half of historical levels. Recent efforts to restore estuarine habitats include tide gate replacement, though this method has been poorly studied. As a key indicator of salmon habitat suitability, temperature was used to evaluate the effects of tide gate replacement in a tidally influenced freshwater slough in the Lower Columbia River estuary. Three tide gates in the largest slough on Tenasillahe Island were replaced in 2007 with side-hinged aluminum gates. As managed during the data collection periods, the new tide gates did not allow tidal inflow into the slough. The study employed a Before-After, Control-Impact (BACI) approach, collecting data seasonally two years before and after replacement at the impact site and at the control site, a relatively unaltered slough on nearby Welch Island. Randomized Intervention Analysis and Monte Carlo tests revealed no significant difference in slough water temperatures after tide gate replacement, although minimum temperatures dropped up and downstream of the tide gates. Although the new tide gates did not have a significant effect on water temperature, the lower minimum temperatures may have been caused by a slight increase in tidal circulation. This result suggests that slough temperatures would decrease if the tide gates were managed to increase tidal inflow, and thus improve the quality of salmon rearing habitat. Close

• 28. [Article] Combined Assimilation of Streamflow and Satellite Soil Moisture with the Particle Filter and Geostatistical Modeling

  Assimilation of satellite soil moisture and streamflow data into a distributed hydrologic model has received increasing attention over the past few years. This study provides a detailed analysis of the ...

  Citation × Citation Citation Abstract Copy Title: Combined Assimilation of Streamflow and Satellite Soil Moisture with the Particle Filter and Geostatistical Modeling Author: Yan, Hongxiang, Moradkhani, Hamid Year: 2016 Assimilation of satellite soil moisture and streamflow data into a distributed hydrologic model has received increasing attention over the past few years. This study provides a detailed analysis of the joint and separate assimilation of streamflow and Advanced Scatterometer (ASCAT) surface soil moisture into a distributed Sacramento Soil Moisture Accounting (SAC-SMA) model, with the use of recently developed particle filter-Markov chain Monte Carlo (PF-MCMC) method. Performance is assessed over the Salt River Watershed in Arizona, which is one of the watersheds without anthropogenic effects in Model Parameter Estimation Experiment (MOPEX). A total of five data assimilation (DA) scenarios are designed and the effects of the locations of streamflow gauges and the ASCAT soil moisture on the predictions of soil moisture and streamflow are assessed. In addition, a geostatistical model is introduced to overcome the significantly biased satellite soil moisture and also discontinuity issue. The results indicate that: (1) solely assimilating outlet streamflow can lead to biased soil moisture estimation; (2) when the study area can only be partially covered by the satellite data, the geostatistical approach can estimate the soil moisture for those uncovered grid cells; (3) joint assimilation of streamflow and soil moisture from geostatistical modeling can further improve the surface soil moisture prediction. This study recommends that the geostatistical model is a helpful tool to aid the remote sensing technique and the hydrologic DA study. Title: Combined Assimilation of Streamflow and Satellite Soil Moisture with the Particle Filter and Geostatistical Modeling Author: Yan, Hongxiang, Moradkhani, Hamid Year: 2016 Assimilation of satellite soil moisture and streamflow data into a distributed hydrologic model has received increasing attention over the past few years. This study provides a detailed analysis of the joint and separate assimilation of streamflow and Advanced Scatterometer (ASCAT) surface soil moisture into a distributed Sacramento Soil Moisture Accounting (SAC-SMA) model, with the use of recently developed particle filter-Markov chain Monte Carlo (PF-MCMC) method. Performance is assessed over the Salt River Watershed in Arizona, which is one of the watersheds without anthropogenic effects in Model Parameter Estimation Experiment (MOPEX). A total of five data assimilation (DA) scenarios are designed and the effects of the locations of streamflow gauges and the ASCAT soil moisture on the predictions of soil moisture and streamflow are assessed. In addition, a geostatistical model is introduced to overcome the significantly biased satellite soil moisture and also discontinuity issue. The results indicate that: (1) solely assimilating outlet streamflow can lead to biased soil moisture estimation; (2) when the study area can only be partially covered by the satellite data, the geostatistical approach can estimate the soil moisture for those uncovered grid cells; (3) joint assimilation of streamflow and soil moisture from geostatistical modeling can further improve the surface soil moisture prediction. This study recommends that the geostatistical model is a helpful tool to aid the remote sensing technique and the hydrologic DA study. Close

• 29. [Article] Implementation of a Sediment Transport Model for CE-QUAL-W2

  The CE-QUAL-W2 model, developed by Portland State University, simulates water quality and flow. Recommendations to expand on this model and have it include sediment transport are implemented in this report. ...

  Citation × Citation Citation Abstract Copy Title: Implementation of a Sediment Transport Model for CE-QUAL-W2 Author: Hanna, Rachel Year: 2014 The CE-QUAL-W2 model, developed by Portland State University, simulates water quality and flow. Recommendations to expand on this model and have it include sediment transport are implemented in this report. Existing one-, two-, and three-dimensional models are reviewed and assessed for their sediment transport methodology. A laterally (width) averaged sediment concentration model is developed as an Upwind Center Space Scheme using CE-QUAL-W2 data. The scheme includes a method to calculate scour for sediment concentration and results of the model are shown for a simulated branch of the Spokane River. Title: Implementation of a Sediment Transport Model for CE-QUAL-W2 Author: Hanna, Rachel Year: 2014 The CE-QUAL-W2 model, developed by Portland State University, simulates water quality and flow. Recommendations to expand on this model and have it include sediment transport are implemented in this report. Existing one-, two-, and three-dimensional models are reviewed and assessed for their sediment transport methodology. A laterally (width) averaged sediment concentration model is developed as an Upwind Center Space Scheme using CE-QUAL-W2 data. The scheme includes a method to calculate scour for sediment concentration and results of the model are shown for a simulated branch of the Spokane River. Close

• 30. [Article] Stream Temperature Management in the Tualatin Watershed: Is it Improving Salmonid Habitat?

  The purpose of this paper is to examine the literature from scientific and governmental entities that describes the problems with elevated stream temperatures in the Tualatin basin, the actions being taken ...

  Citation × Citation Citation Abstract Copy Title: Stream Temperature Management in the Tualatin Watershed: Is it Improving Salmonid Habitat? Author: Hennings, Raymond Banks Year: 2014 The purpose of this paper is to examine the literature from scientific and governmental entities that describes the problems with elevated stream temperatures in the Tualatin basin, the actions being taken to resolve those problems, and to assess whether these actions are meeting the goal of improving salmonid habitat in the basin. Elevated stream temperatures are considered a pollutant under the US Clean Water Act (Clean Water Act 1972, as amended) because increased stream temperatures can be harmful to native aquatic biota, particularly salmonid fish species that have evolved to use cold water (IMST 2004). Title: Stream Temperature Management in the Tualatin Watershed: Is it Improving Salmonid Habitat? Author: Hennings, Raymond Banks Year: 2014 The purpose of this paper is to examine the literature from scientific and governmental entities that describes the problems with elevated stream temperatures in the Tualatin basin, the actions being taken to resolve those problems, and to assess whether these actions are meeting the goal of improving salmonid habitat in the basin. Elevated stream temperatures are considered a pollutant under the US Clean Water Act (Clean Water Act 1972, as amended) because increased stream temperatures can be harmful to native aquatic biota, particularly salmonid fish species that have evolved to use cold water (IMST 2004). Close