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• 1. [Article] Moving beyond heterogeneity and process complexity: A new vision for watershed hydrology

  This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/wr/.

  Citation × Citation Citation Abstract Copy Title: Moving beyond heterogeneity and process complexity: A new vision for watershed hydrology Author: Vache, K., Kirchner, J., Dunn, S., Hinz, C., Roderick, M. L., Sivapalan, M., Weiler, M., Haggerty, R., Grant, G., Selker, J., McDonnell, J. J., Hooper, R. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/wr/. Title: Moving beyond heterogeneity and process complexity: A new vision for watershed hydrology Author: Vache, K., Kirchner, J., Dunn, S., Hinz, C., Roderick, M. L., Sivapalan, M., Weiler, M., Haggerty, R., Grant, G., Selker, J., McDonnell, J. J., Hooper, R. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/wr/. Close

• 2. [Article] Simulation of melt pond evolution on level ice

  A melt pond model is presented that predicts pond size and depth changes, given an initial ice thickness field and representative surface fluxes. The model is based on the assumption that as sea ice melts, ...

  Citation × Citation Citation Abstract Copy Title: Simulation of melt pond evolution on level ice Author: Skyllingstad, Eric D., Paulson, Clayton A., Perovich, Donald K. A melt pond model is presented that predicts pond size and depth changes, given an initial ice thickness field and representative surface fluxes. The model is based on the assumption that as sea ice melts, fresh water builds up in the ice pore space and eventually saturates the ice. Under these conditions, a water table is defined equal to the draft of the ice or sea level, and ponds are produced in ice surface depressions, much like lakes in a watershed. Pond evolution is forced by applying fluxes of heat at the pond surface and a radiative transfer model for solar radiation that penetrates the pond. Results from the model using forcing data from the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment and representative pond parameters indicate that the model accurately simulates pond depth and fractional area over the summer melt season, with fractional area increasing linearly. Overall, ice albedo is affected primarily by the increase in pond coverage. Decrease in pond albedo from pond deepening has a much lower influence on the total albedo. Cases with predominately sunny conditions are shown to produce more rapid pond expansion than overcast cases. In both sunny and cloudy cases the fractional area increases linearly. Title: Simulation of melt pond evolution on level ice Author: Skyllingstad, Eric D., Paulson, Clayton A., Perovich, Donald K. A melt pond model is presented that predicts pond size and depth changes, given an initial ice thickness field and representative surface fluxes. The model is based on the assumption that as sea ice melts, fresh water builds up in the ice pore space and eventually saturates the ice. Under these conditions, a water table is defined equal to the draft of the ice or sea level, and ponds are produced in ice surface depressions, much like lakes in a watershed. Pond evolution is forced by applying fluxes of heat at the pond surface and a radiative transfer model for solar radiation that penetrates the pond. Results from the model using forcing data from the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment and representative pond parameters indicate that the model accurately simulates pond depth and fractional area over the summer melt season, with fractional area increasing linearly. Overall, ice albedo is affected primarily by the increase in pond coverage. Decrease in pond albedo from pond deepening has a much lower influence on the total albedo. Cases with predominately sunny conditions are shown to produce more rapid pond expansion than overcast cases. In both sunny and cloudy cases the fractional area increases linearly. Close

• 3. [Article] Representation of a subsurface storm flow and a more responsive water table in a TOPMODEL-based hydrology model

  This study presents two new modeling strategies. First, a methodology for representing the physical process of subsurface storm flow within a TOPMODEL framework is developed. In using this approach, discharge ...

  Citation × Citation Citation Abstract Copy Title: Representation of a subsurface storm flow and a more responsive water table in a TOPMODEL-based hydrology model Author: Stieglitz, Marc, Engel, Victor, Shaman, Jeffrey, Koster, Randal This study presents two new modeling strategies. First, a methodology for representing the physical process of subsurface storm flow within a TOPMODEL framework is developed. In using this approach, discharge at quick flow timescales is simulated, and a fuller depiction of hydrologic activity is brought about. Discharge of water from the vadose zone is permitted in a physically realistic manner without a priori assumption of the level within the soil column at which subsurface storm flow saturation can take place. Determination of the subsurface storm flow contribution to discharge is made using the equation for groundwater flow. No new parameters are needed. Instead, regions in excess of field capacity that develop during storm events, producing vertical recharge, are also allowed to contribute to soil zone discharge. These subsurface storm flow contributions to river runoff, as for groundwater flow contributions, are a function of catchment topography and hydraulic conductivity at the depth at which such regions in excess of field capacity occur. The second approach improves groundwater flow response through a reduction of porosity and field capacity with depth in the soil column. Large storm events are better captured and a more dynamic water table develops with application of this modified soil column profile (MSCP). The MSCP predominantly reflects soil depth differences in upland and lowland regions of a watershed. Combined, these two approaches, subsurface storm flow and the MSCP, provide a more accurate representation of the timescales at which discharge responds and a more complete depiction of hydrologic activity. Storm events large and small are better simulated, and some of the biases previously evident in TOPMODEL simulations are reduced. Title: Representation of a subsurface storm flow and a more responsive water table in a TOPMODEL-based hydrology model Author: Stieglitz, Marc, Engel, Victor, Shaman, Jeffrey, Koster, Randal This study presents two new modeling strategies. First, a methodology for representing the physical process of subsurface storm flow within a TOPMODEL framework is developed. In using this approach, discharge at quick flow timescales is simulated, and a fuller depiction of hydrologic activity is brought about. Discharge of water from the vadose zone is permitted in a physically realistic manner without a priori assumption of the level within the soil column at which subsurface storm flow saturation can take place. Determination of the subsurface storm flow contribution to discharge is made using the equation for groundwater flow. No new parameters are needed. Instead, regions in excess of field capacity that develop during storm events, producing vertical recharge, are also allowed to contribute to soil zone discharge. These subsurface storm flow contributions to river runoff, as for groundwater flow contributions, are a function of catchment topography and hydraulic conductivity at the depth at which such regions in excess of field capacity occur. The second approach improves groundwater flow response through a reduction of porosity and field capacity with depth in the soil column. Large storm events are better captured and a more dynamic water table develops with application of this modified soil column profile (MSCP). The MSCP predominantly reflects soil depth differences in upland and lowland regions of a watershed. Combined, these two approaches, subsurface storm flow and the MSCP, provide a more accurate representation of the timescales at which discharge responds and a more complete depiction of hydrologic activity. Storm events large and small are better simulated, and some of the biases previously evident in TOPMODEL simulations are reduced. Close

• 4. [Article] Vegetation and stem mapping of watershed 10, H. J. Andrews Experimental Forest

  Stem mapping of all trees greater than 15 cm dbh has been completed on the 10.24 hectare watershed (No. 10) at H. J. Andrews intensive study site. Using a 25 m grid system, mapping of vegetation into 7 ...

  Citation × Citation Citation Abstract Copy Title: Vegetation and stem mapping of watershed 10, H. J. Andrews Experimental Forest Author: Hawk, Glenn M., U.S. International Biological Program. Coniferous Forest Biome, University of Washington Stem mapping of all trees greater than 15 cm dbh has been completed on the 10.24 hectare watershed (No. 10) at H. J. Andrews intensive study site. Using a 25 m grid system, mapping of vegetation into 7 plant communities and then into 4 habitat types has also been completed. Descriptions of these communities based on field notes and extrapolation from reference stands located in the Andrews Experimental Forest are included along with structural characteristics of the communities and habitat types. Size class distributions of living trees greater than 15 cm dbh are also included for the whole watershed, for communities, and for habitat types. INTRODUCTION: Watershed 10 has been selected for current modeling efforts of the IBP Coniferous Forest Biome project at the Oregon intensive study site, H. J. Andrews Experimental Forest. This report supplies a necessary input for calculating standing crop of vegetation in all strata from trees to mosses. A community description approach has been used with tables and appendices furnishing data concerning trees, shrubs, herbs and mosses occurring within the watershed. Watershed 10 contains representatives of communities common to the lower elevation regions of the Tsuga hetero h lla Zone of Franklin and Dyrness (1969). Within watershed communities are identified, which are discussed below. Major emphasis of this report is placed on description of the vegetation. Some comparisons of communities with each other and with other portions of the Tsuga heterophylla Zone near the H. J. Andrews Experimental Forest are also included. Watershed 10 is a 10.24 hectare watershed that drains to the west. It is located near to but outside of the southwestern boundary of the Experimental Forest. The elevation of the watershed ranges from 1425 feet (435 m) to 2,275 feet (695 m). The entire watershed lies within the Tsuga heterophylla.Zone of Franklin and Dyrness. METHODS: Preliminary surveying of watershed 10 with staff compass, chains and Abney levels was completed in 1970. During this surveying three base lines running north and south were established at equal intervals within the watershed. These base lines served as reference points during the establishment of a 25 m grid system in 1971-1972. Using staff compass, chains, and Abney levels, the 25 m grid system was established with correction for slope over the entire watershed (figure 1). During spring, 1972, aluminum corner stakes were installed and labeled to mark the 25 meter grid corners. Grid sections were numbered, for referencing positions in the watershed. Title: Vegetation and stem mapping of watershed 10, H. J. Andrews Experimental Forest Author: Hawk, Glenn M., U.S. International Biological Program. Coniferous Forest Biome, University of Washington Stem mapping of all trees greater than 15 cm dbh has been completed on the 10.24 hectare watershed (No. 10) at H. J. Andrews intensive study site. Using a 25 m grid system, mapping of vegetation into 7 plant communities and then into 4 habitat types has also been completed. Descriptions of these communities based on field notes and extrapolation from reference stands located in the Andrews Experimental Forest are included along with structural characteristics of the communities and habitat types. Size class distributions of living trees greater than 15 cm dbh are also included for the whole watershed, for communities, and for habitat types. INTRODUCTION: Watershed 10 has been selected for current modeling efforts of the IBP Coniferous Forest Biome project at the Oregon intensive study site, H. J. Andrews Experimental Forest. This report supplies a necessary input for calculating standing crop of vegetation in all strata from trees to mosses. A community description approach has been used with tables and appendices furnishing data concerning trees, shrubs, herbs and mosses occurring within the watershed. Watershed 10 contains representatives of communities common to the lower elevation regions of the Tsuga hetero h lla Zone of Franklin and Dyrness (1969). Within watershed communities are identified, which are discussed below. Major emphasis of this report is placed on description of the vegetation. Some comparisons of communities with each other and with other portions of the Tsuga heterophylla Zone near the H. J. Andrews Experimental Forest are also included. Watershed 10 is a 10.24 hectare watershed that drains to the west. It is located near to but outside of the southwestern boundary of the Experimental Forest. The elevation of the watershed ranges from 1425 feet (435 m) to 2,275 feet (695 m). The entire watershed lies within the Tsuga heterophylla.Zone of Franklin and Dyrness. METHODS: Preliminary surveying of watershed 10 with staff compass, chains and Abney levels was completed in 1970. During this surveying three base lines running north and south were established at equal intervals within the watershed. These base lines served as reference points during the establishment of a 25 m grid system in 1971-1972. Using staff compass, chains, and Abney levels, the 25 m grid system was established with correction for slope over the entire watershed (figure 1). During spring, 1972, aluminum corner stakes were installed and labeled to mark the 25 meter grid corners. Grid sections were numbered, for referencing positions in the watershed. 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• 5. [Article] Report of the aquatic modeling group : round one

  The aquatic modeling group, consisting of Davis, Donaldson, Hall, Higley, Lyford, McIntire, Mullooly, Overton, Strand, Waring, and Warren, met in four 2-hour sessions from July 7 to July 26. The charge ...

  Citation × Citation Citation Abstract Copy Title: Report of the aquatic modeling group : round one Author: Hall, James D., Higley, Duane Lee, McIntire, C. David, University of Washington, U.S. International Biological Program. Coniferous Forest Biome The aquatic modeling group, consisting of Davis, Donaldson, Hall, Higley, Lyford, McIntire, Mullooly, Overton, Strand, Waring, and Warren, met in four 2-hour sessions from July 7 to July 26. The charge to the group was: 1. Define an appropriate internal structure for the aquatic subsystem; 2. Define significant couplings between the aquatic and terrestrial systems; and 3. Begin to evaluate the present program with the above as background. In general, the discussion centered around stream systems, and specifically around the Lookout Creek drainage on the H. J. Andrews Forest, site of most of the Oregon field research. Much consideration. was given to the best means of incorporating data from earlier studies on Berry Creek, the Drift Creek streams (Alsea Watershed Study), and the Oak Creek Experimental Streams into present modeling efforts. Higley is charged with the responsibility of bringing together a listing of the pertinent publications and theses that might be most applicable to this effort. A tentative listing is included with this report. Title: Report of the aquatic modeling group : round one Author: Hall, James D., Higley, Duane Lee, McIntire, C. David, University of Washington, U.S. International Biological Program. Coniferous Forest Biome The aquatic modeling group, consisting of Davis, Donaldson, Hall, Higley, Lyford, McIntire, Mullooly, Overton, Strand, Waring, and Warren, met in four 2-hour sessions from July 7 to July 26. The charge to the group was: 1. Define an appropriate internal structure for the aquatic subsystem; 2. Define significant couplings between the aquatic and terrestrial systems; and 3. Begin to evaluate the present program with the above as background. In general, the discussion centered around stream systems, and specifically around the Lookout Creek drainage on the H. J. Andrews Forest, site of most of the Oregon field research. Much consideration. was given to the best means of incorporating data from earlier studies on Berry Creek, the Drift Creek streams (Alsea Watershed Study), and the Oak Creek Experimental Streams into present modeling efforts. Higley is charged with the responsibility of bringing together a listing of the pertinent publications and theses that might be most applicable to this effort. A tentative listing is included with this report. Close

• 6. [Article] Movement of water through forested soils in steep topography

  Field and laboratory studies are being conducted to describe the hydrologic properties of soil and to determine the timing pathway of precipitation and snowmelt water as it moved through forested soil ...

  Citation × Citation Citation Abstract Copy Title: Movement of water through forested soils in steep topography Author: U.S. International Biological Program. Coniferous Forest Biome, Harr, R. Dennis (Robert Dennis), 1941-, Ranken, Darren W., University of Washington Field and laboratory studies are being conducted to describe the hydrologic properties of soil and to determine the timing pathway of precipitation and snowmelt water as it moved through forested soil on a steep slope. Hydrologic properties include hydraulic conductivity, porosity, pore-size distribution, moisture characteristics, stone content, and soil depth. Laboratory analyses indicated an abrupt change in hydrologic properties within the top 1.5 m of soil. Water input and movement through the soil are being monitored during winter storm events. Title: Movement of water through forested soils in steep topography Author: U.S. International Biological Program. Coniferous Forest Biome, Harr, R. Dennis (Robert Dennis), 1941-, Ranken, Darren W., University of Washington Field and laboratory studies are being conducted to describe the hydrologic properties of soil and to determine the timing pathway of precipitation and snowmelt water as it moved through forested soil on a steep slope. Hydrologic properties include hydraulic conductivity, porosity, pore-size distribution, moisture characteristics, stone content, and soil depth. Laboratory analyses indicated an abrupt change in hydrologic properties within the top 1.5 m of soil. Water input and movement through the soil are being monitored during winter storm events. Close

• 7. [Article] Airborne Light Detection and Ranging (LiDAR) for Individual Tree Stem Location, Height, and Biomass Measurements

  This is the publisher’s final pdf. The published article is copyrighted by MDPI and can be found at: http://www.mdpi.com/journal/remotesensing.

  Citation × Citation Citation Abstract Copy Title: Airborne Light Detection and Ranging (LiDAR) for Individual Tree Stem Location, Height, and Biomass Measurements Author: Edson, Curtis, Wing, Michael G. This is the publisher’s final pdf. The published article is copyrighted by MDPI and can be found at: http://www.mdpi.com/journal/remotesensing. Title: Airborne Light Detection and Ranging (LiDAR) for Individual Tree Stem Location, Height, and Biomass Measurements Author: Edson, Curtis, Wing, Michael G. This is the publisher’s final pdf. The published article is copyrighted by MDPI and can be found at: http://www.mdpi.com/journal/remotesensing. Close

• 8. [Article] Variability in expression of anadromy by female Oncorhynchus mykiss within a river network

  We described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss in the John Day River watershed, Oregon. We collected 149 juvenile O. mykiss across 72 sites and ...

  Citation × Citation Citation Abstract Copy Title: Variability in expression of anadromy by female Oncorhynchus mykiss within a river network Author: Zimmerman, Christian E., Jordan, Chris E., McMillan, John R., Mills, Justin S., Dunham, Jason B., Reeves, Gordon H. We described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss in the John Day River watershed, Oregon. We collected 149 juvenile O. mykiss across 72 sites and identified locations used by anadromous females by assigning maternal origin (anadromous versus non-anadromous) to each juvenile. These assignments used comparisons of strontium to calcium ratios in otolith primordia and freshwater growth regions to indicate maternal origin. We used logistic regression to predict probability of anadromy in relation to mean annual stream runoff using data from a subset of individuals. This model correctly predicted anadromy in a second sample of individuals with a moderate level of accuracy (e.g., 68% correctly predicted with a 0.5 classification threshold). Residuals from the models were not spatially autocorrelated, suggesting that remaining variability in the expression of anadromy was due to localized influences, as opposed to broad-scale gradients unrelated to mean annual stream runoff. These results are important for the management of O. mykiss because anadromous individuals (steelhead) within the John Day River watershed are listed as a threatened species, and it is difficult to discern juvenile steelhead from non-anadromous individuals (rainbow trout) in the field. Our results provide a broad-scale description and prediction of locations supporting anadromy, and new insight for habitat restoration, monitoring, and research to better manage and understand the expression of anadromy in O. mykiss. Title: Variability in expression of anadromy by female Oncorhynchus mykiss within a river network Author: Zimmerman, Christian E., Jordan, Chris E., McMillan, John R., Mills, Justin S., Dunham, Jason B., Reeves, Gordon H. We described and predicted spatial variation in marine migration (anadromy) of female Oncorhynchus mykiss in the John Day River watershed, Oregon. We collected 149 juvenile O. mykiss across 72 sites and identified locations used by anadromous females by assigning maternal origin (anadromous versus non-anadromous) to each juvenile. These assignments used comparisons of strontium to calcium ratios in otolith primordia and freshwater growth regions to indicate maternal origin. We used logistic regression to predict probability of anadromy in relation to mean annual stream runoff using data from a subset of individuals. This model correctly predicted anadromy in a second sample of individuals with a moderate level of accuracy (e.g., 68% correctly predicted with a 0.5 classification threshold). Residuals from the models were not spatially autocorrelated, suggesting that remaining variability in the expression of anadromy was due to localized influences, as opposed to broad-scale gradients unrelated to mean annual stream runoff. These results are important for the management of O. mykiss because anadromous individuals (steelhead) within the John Day River watershed are listed as a threatened species, and it is difficult to discern juvenile steelhead from non-anadromous individuals (rainbow trout) in the field. Our results provide a broad-scale description and prediction of locations supporting anadromy, and new insight for habitat restoration, monitoring, and research to better manage and understand the expression of anadromy in O. mykiss. Close

• 9. [Article] An a priori process for selecting candidate reference lakes for a national survey

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The Society ...

  Citation × Citation Citation Abstract Copy Title: An a priori process for selecting candidate reference lakes for a national survey Author: Sullivan, Timothy J., Sobota, Janel Banks, Herlihy, Alan T., McDonnell, Todd C., Tarquinio, Ellen, Lehmann, Sarah To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The Society for Freshwater Science and can be found at: http://www.freshwater-science.org/. Title: An a priori process for selecting candidate reference lakes for a national survey Author: Sullivan, Timothy J., Sobota, Janel Banks, Herlihy, Alan T., McDonnell, Todd C., Tarquinio, Ellen, Lehmann, Sarah To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by The Society for Freshwater Science and can be found at: http://www.freshwater-science.org/. Close

• 10. [Article] Historical change in channel form and riparian vegetation of the McKenzie River, Oregon

  This study examined channel structure and position and riparian vegetation and land use on the upper 70 km of the McKenzie River, Oregon in the 1940s, compared the 1940s conditions to present conditions, ...

  Citation × Citation Citation Abstract Copy Title: Historical change in channel form and riparian vegetation of the McKenzie River, Oregon Author: Minear, Paula J. This study examined channel structure and position and riparian vegetation and land use on the upper 70 km of the McKenzie River, Oregon in the 1940s, compared the 1940s conditions to present conditions, and explored the processes driving change in this system and the implications for aquatic habitat. The hydrologic record was analyzed, and field surveys were conducted and compared to historical habitat surveys. Riparian characteristics and channel features were digitized from aerial photographs from 1945/49 and 1986 and imported into Arcinfo GIS for analysis. Types of data digitized from the aerial photos included locations and length or area of wetted channel, active channel, tributaries, side channels, large woody debris, exposed gravel bars, roads, and dominant vegetation or land use within 200 m of the active channel. Construction of dams on the mainstem Mckenzie River and two major tributaries, Blue River and South Fork, in the 1960s has altered the flow regime and sediment supply to the mainstem Mckenzie, decreasing the frequency, mean and variation of peak flows, reducing the competence of flows to move existing bedload, and cutting off sediment from over half of the drainage area. Mean peak flows decreased 44% and competence of peak flows with a 2-yr recurrence interval declined approximately 29% after dams were constructed upriver. Adjustments to reduced sediment supply and flow alteration by dams in this system included 57% decrease in exposed gravel bars, 40% decrease in side channel length, and possible substrate coarsening (as compared to historical estimates). Channel straightening occurred in each of three instances of channel change during the study period, and sinuosity decreased one half of the amount needed to produce a straight channel in the most susceptible, unconstrained reach. Human actions prior to high flow events played a role in the direction of channel change in each case. Over the entire study area, 7% of the main channel changed position by 30 m or more and little or no change in channel position was noted in reaches constrained by valley floors. Additional channel constraint has been produced by road construction near the channel and riprapping for roads, bridges, and residences. Less large woody debris was observed in the 1986 channel than in the 1949 channel, indicating a reduction in pool-forming agents and channel roughness elements. Frequency of large pools ([greater than or equal to] 2 m depth and >40 m² area) decreased 19% over the study area. The greatest loss in pools (73%) was noted in the unconstrained reach that exhibited two areas of channel change and an increase in exposed gravel bars. Increased human use of the riparian area for roads and residential purposes has led to an increased fragmentation of the riparian landscape. Density of residential or developed patches within the riparian area has increased 215% as more and smaller areas are converted from natural vegetation to human use. Riparian area devoted to roads and residential uses has nearly doubled since the 1940s. Mean vegetation or land-use patch size has decreased from 2.2 ha to 1.6 ha as larger patches have been sub-divided, and patch and edge densities have increased. Agriculture and clearcuts for timber removal have decreased within the riparian area while continuing upslope. Riparian area in mature conifers has decreased 44% from levels in the 1940s while hardwoods have increased 45% in the riparian area. Future wood loading to the channel is reduced by a decline in mature riparian vegetation, especially mature conifers. Channel and riparian changes noted in this study have implications for fish populations. Channel straightening, reduction in side channels, and loss of pool-forming agents reduce habitat heterogeneity and off-channel refugia. Ecosystem management of watersheds requires evaluation of conditions across scales of time and space. The use of GIS in this study made it possible to detect changes in channel form and riparian conditions during four decades, along a 70-m channel and 90-m riparian area and to analyze the large data sets relevant to understanding functions and change in channels and riparian areas. Title: Historical change in channel form and riparian vegetation of the McKenzie River, Oregon Author: Minear, Paula J. This study examined channel structure and position and riparian vegetation and land use on the upper 70 km of the McKenzie River, Oregon in the 1940s, compared the 1940s conditions to present conditions, and explored the processes driving change in this system and the implications for aquatic habitat. The hydrologic record was analyzed, and field surveys were conducted and compared to historical habitat surveys. Riparian characteristics and channel features were digitized from aerial photographs from 1945/49 and 1986 and imported into Arcinfo GIS for analysis. Types of data digitized from the aerial photos included locations and length or area of wetted channel, active channel, tributaries, side channels, large woody debris, exposed gravel bars, roads, and dominant vegetation or land use within 200 m of the active channel. Construction of dams on the mainstem Mckenzie River and two major tributaries, Blue River and South Fork, in the 1960s has altered the flow regime and sediment supply to the mainstem Mckenzie, decreasing the frequency, mean and variation of peak flows, reducing the competence of flows to move existing bedload, and cutting off sediment from over half of the drainage area. Mean peak flows decreased 44% and competence of peak flows with a 2-yr recurrence interval declined approximately 29% after dams were constructed upriver. Adjustments to reduced sediment supply and flow alteration by dams in this system included 57% decrease in exposed gravel bars, 40% decrease in side channel length, and possible substrate coarsening (as compared to historical estimates). Channel straightening occurred in each of three instances of channel change during the study period, and sinuosity decreased one half of the amount needed to produce a straight channel in the most susceptible, unconstrained reach. Human actions prior to high flow events played a role in the direction of channel change in each case. Over the entire study area, 7% of the main channel changed position by 30 m or more and little or no change in channel position was noted in reaches constrained by valley floors. Additional channel constraint has been produced by road construction near the channel and riprapping for roads, bridges, and residences. Less large woody debris was observed in the 1986 channel than in the 1949 channel, indicating a reduction in pool-forming agents and channel roughness elements. Frequency of large pools ([greater than or equal to] 2 m depth and >40 m² area) decreased 19% over the study area. The greatest loss in pools (73%) was noted in the unconstrained reach that exhibited two areas of channel change and an increase in exposed gravel bars. Increased human use of the riparian area for roads and residential purposes has led to an increased fragmentation of the riparian landscape. Density of residential or developed patches within the riparian area has increased 215% as more and smaller areas are converted from natural vegetation to human use. Riparian area devoted to roads and residential uses has nearly doubled since the 1940s. Mean vegetation or land-use patch size has decreased from 2.2 ha to 1.6 ha as larger patches have been sub-divided, and patch and edge densities have increased. Agriculture and clearcuts for timber removal have decreased within the riparian area while continuing upslope. Riparian area in mature conifers has decreased 44% from levels in the 1940s while hardwoods have increased 45% in the riparian area. Future wood loading to the channel is reduced by a decline in mature riparian vegetation, especially mature conifers. Channel and riparian changes noted in this study have implications for fish populations. Channel straightening, reduction in side channels, and loss of pool-forming agents reduce habitat heterogeneity and off-channel refugia. Ecosystem management of watersheds requires evaluation of conditions across scales of time and space. The use of GIS in this study made it possible to detect changes in channel form and riparian conditions during four decades, along a 70-m channel and 90-m riparian area and to analyze the large data sets relevant to understanding functions and change in channels and riparian areas. Close