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• 51. [Article] Digital Watersheds: One Library's Approach to Expanding Access to Water Resources Information

  Published in the Proceedings of the Geoscience Information Society, volume 39, 2008.

  Citation × Citation Citation Abstract Copy Title: Digital Watersheds: One Library's Approach to Expanding Access to Water Resources Information Author: Wirth, Andrea A. Published in the Proceedings of the Geoscience Information Society, volume 39, 2008. Title: Digital Watersheds: One Library's Approach to Expanding Access to Water Resources Information Author: Wirth, Andrea A. Published in the Proceedings of the Geoscience Information Society, volume 39, 2008. Close

• 52. [Article] Do vigorous young forests reduce streamflow? Results from up to 54 years of streamflow records in eight paired-watershed experiments in the H. J. Andrews and South Umpqua Experimental Forests

  This study quantified the magnitude and timing of summer streamflow deficits in paired-watershed experiments in the Cascade Range of Oregon where mature and old-growth conifer forests were subjected to ...

  Citation × Citation Citation Abstract Copy Title: Do vigorous young forests reduce streamflow? Results from up to 54 years of streamflow records in eight paired-watershed experiments in the H. J. Andrews and South Umpqua Experimental Forests Author: Perry, Timothy D. This study quantified the magnitude and timing of summer streamflow deficits in paired-watershed experiments in the Cascade Range of Oregon where mature and old-growth conifer forests were subjected to clearcutting, patch cutting, and overstory thinning treatments in the 1960s and 1970s. Hydrologic effects of clearcutting, small-patch cutting, and overstory thinning in the mixed conifer/brush zone were studied (1 watershed (WS) each) in the Coyote Creek WS of the South Umpqua Experimental Forest at 42° 1' 15"N and 122° 43' 30"W. Hydrologic effects of clear cutting (3 WS), shelterwood cutting (1 WS), patch cutting (1 WS), and young forest thinning (1 WS) were examined in the Tsuga heterophylla zone at the H. J. Andrews experimental forest at 44° 14' 0"N and 122° 11' 0" W. Climate of both sites is marine west coast with winter precipitation and dry summers, producing minimum streamflows in August and September. Changes in flow frequency distributions were detected by counting days below streamflow thresholds where the thresholds were established using percentiles from pre-cutting streamflow records. Changes in relative streamflow were established by the station pair method. Summer streamflow deficits were largest and most persistent in 35 to 50-year-old forest plantations created from clearcutting and shelterwood cutting in the 1960s and 1970s. Summer streamflow deficits were smallest and most ephemeral in a stand that experienced 50% overstory thinning in 1971. Summer streamflow deficits of intermediate size and persistence developed in watersheds in which 25 to 30% of the area had been patchcut in the 1960s or 1970s. A sparse (12%) precommercial thin of a 27-year-old stand exhibiting summer streamflow deficits had comparatively little effect on streamflow deficits. Streamflow deficits emerged as early as March or April and persisted into October and November in the warmer, drier site in southern Oregon (Coyote Creek), whereas summer streamflow deficits were restricted to July through September in the cooler, wetter Andrews Forest. These findings are consistent with previous studies demonstrating (1) increases in water use in certain conifer species relative to others (e.g. Douglas-fir versus pine); (2) higher water use in young (i.e., 10 to 50-yr-old) compared to old (100 to 250-yr-old) stands of many tree species; and (3) decreased interception capacity of young relative to old forest stands associated with loss of canopy epiphytes. Results appear to be robust, despite gaps in data availability, uncertainties associated with changes in stream gauging, streamflow trends over time in control watersheds, and multi-decadal fluctuations in regional climate over the study period. These findings support the notion that variable-intensity logging prescriptions over small areas to approximate natural forest structure may have the least effect on summer streamflows. However, more research, preferably new paired watershed experiments, is needed to quantify the magnitude and duration of summer streamflow effects from various levels of overstory and understory thinning treatments. Title: Do vigorous young forests reduce streamflow? Results from up to 54 years of streamflow records in eight paired-watershed experiments in the H. J. Andrews and South Umpqua Experimental Forests Author: Perry, Timothy D. This study quantified the magnitude and timing of summer streamflow deficits in paired-watershed experiments in the Cascade Range of Oregon where mature and old-growth conifer forests were subjected to clearcutting, patch cutting, and overstory thinning treatments in the 1960s and 1970s. Hydrologic effects of clearcutting, small-patch cutting, and overstory thinning in the mixed conifer/brush zone were studied (1 watershed (WS) each) in the Coyote Creek WS of the South Umpqua Experimental Forest at 42° 1' 15"N and 122° 43' 30"W. Hydrologic effects of clear cutting (3 WS), shelterwood cutting (1 WS), patch cutting (1 WS), and young forest thinning (1 WS) were examined in the Tsuga heterophylla zone at the H. J. Andrews experimental forest at 44° 14' 0"N and 122° 11' 0" W. Climate of both sites is marine west coast with winter precipitation and dry summers, producing minimum streamflows in August and September. Changes in flow frequency distributions were detected by counting days below streamflow thresholds where the thresholds were established using percentiles from pre-cutting streamflow records. Changes in relative streamflow were established by the station pair method. Summer streamflow deficits were largest and most persistent in 35 to 50-year-old forest plantations created from clearcutting and shelterwood cutting in the 1960s and 1970s. Summer streamflow deficits were smallest and most ephemeral in a stand that experienced 50% overstory thinning in 1971. Summer streamflow deficits of intermediate size and persistence developed in watersheds in which 25 to 30% of the area had been patchcut in the 1960s or 1970s. A sparse (12%) precommercial thin of a 27-year-old stand exhibiting summer streamflow deficits had comparatively little effect on streamflow deficits. Streamflow deficits emerged as early as March or April and persisted into October and November in the warmer, drier site in southern Oregon (Coyote Creek), whereas summer streamflow deficits were restricted to July through September in the cooler, wetter Andrews Forest. These findings are consistent with previous studies demonstrating (1) increases in water use in certain conifer species relative to others (e.g. Douglas-fir versus pine); (2) higher water use in young (i.e., 10 to 50-yr-old) compared to old (100 to 250-yr-old) stands of many tree species; and (3) decreased interception capacity of young relative to old forest stands associated with loss of canopy epiphytes. Results appear to be robust, despite gaps in data availability, uncertainties associated with changes in stream gauging, streamflow trends over time in control watersheds, and multi-decadal fluctuations in regional climate over the study period. These findings support the notion that variable-intensity logging prescriptions over small areas to approximate natural forest structure may have the least effect on summer streamflows. However, more research, preferably new paired watershed experiments, is needed to quantify the magnitude and duration of summer streamflow effects from various levels of overstory and understory thinning treatments. Close

• 53. [Article] An inventory of filled lands in the Umpqua River Estuary

  Master files scanned at 600 dpi (256 Grayscale) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 dpi (256 B&W) using Capture Perfect 3.0 and OmniPage Professional ...

  Citation × Citation Citation Abstract Copy Title: An inventory of filled lands in the Umpqua River Estuary Author: Hamilton, Stanley F., Advisory Committee to the State Land Board Master files scanned at 600 dpi (256 Grayscale) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 dpi (256 B&W) using Capture Perfect 3.0 and OmniPage Professional 15.0 for textual OCR on a Canon DR-9080C. Title: An inventory of filled lands in the Umpqua River Estuary Author: Hamilton, Stanley F., Advisory Committee to the State Land Board Master files scanned at 600 dpi (256 Grayscale) using Capture Perfect 3.0 on a Canon DR-9080C in TIF format. PDF derivative scanned at 300 dpi (256 B&W) using Capture Perfect 3.0 and OmniPage Professional 15.0 for textual OCR on a Canon DR-9080C. Close

• 54. [Article] Thirty-five years of forest succession in southwest Oregon : vegetation response to three distinct logging treatments

  This study examined patterns and controls on 35-years of forest succession following logging in the 236 ha South Umpqua Experimental Forest within the Umpqua National Forest in southwestern Oregon. Prior ...

  Citation × Citation Citation Abstract Copy Title: Thirty-five years of forest succession in southwest Oregon : vegetation response to three distinct logging treatments Author: Arthur, Aaron Stone This study examined patterns and controls on 35-years of forest succession following logging in the 236 ha South Umpqua Experimental Forest within the Umpqua National Forest in southwestern Oregon. Prior to logging, the overstory in all three watersheds (~50% cover) was composed of Douglas-fir (30-40% cover), grand fir (2 to 10% cover), incense cedar (2-4% cover), western hemlock (1-2 % cover), sugar pine (1-2% cover), ponderosa pine (0-1% cover), and madrone (0-1% cover). The sapling cover in all three watersheds (30-35% cover) was dominated by grand fir (15-20%), western hemlock (6-8% cover) incense cedar (3-5% cover), and Douglas-fir (3-5% cover), with <1% cover by the other tree species. In 1971, the overstory of the four watersheds received: WS-1 (69.2 ha) a 50% basal area removal (shelterwood); WS-2 (68.4 ha) 30% in 20 small clearcuts; WS-3 (49.8 ha) 100% clearcut; WS-4 (48.6 ha) uncut control. Prior to treatment, tree, shrub, and herb cover in WS 1-3 (n = 50 plots) was visually estimated using the reconnaissance survey method, but only WS 2-3 annually through 1981 (n = 39 plots). In 2006, plots were relocated and new plots added, and resurveyed (n = 77 plots). Plots were classified by environmental (aspect, slope, soil series, vegetation community) and disturbance factors (treatment, logging method, in-watershed location, and soil disturbance). Vegetation was classed into three groups: (1) vegetation structures; (2) overstory species; and (3) residual and invader understory species. Total vegetation cover decreased slightly over the 35-year period, with a slight decrease in shrubs, saplings, and herbs, and an increase in overstory tree cover in 2006 compared to 1971. Few statistically significant differences were observed in vegetation cover change according to environmental variables. However heavily disturbed sites were characterized by low shrub cover and high overstory cover, compared to lightly disturbed sites. These differences were still apparent 35 years after logging. Between 1971 and 2006 in WS-2 and WS-3, Douglas fir, incense cedar and ponderosa pine cover significantly increased, while other overstory species declined. In contrast, over the same period in WS-1, there was a significant change in grand fir and western hemlock cover. Sapling cover of all species stayed constant or declined in all watersheds, except Douglas-fir and western hemlock, which increased in WS-1 only. In the post-logging period, cover of ponderosa pine and Douglas fir cover was significantly higher on moderately and heavily disturbed plots compared to lightly disturbed plots. Before logging, residual species cover was significantly higher than invader species cover. Disturbance appeared to have the greatest effect upon the residual-invader species relationship. Residual species maintained higher cover on lightly disturbed plots, compared to invader species cover, which was highest on moderately and heavily disturbed plots. All species declined in WS-2 and WS-3 following stem exclusion. Overall patterns of tree, shrub, and herb cover succession over the 35-year post-logging period were consistent with the expected effects of clearcutting versus thinning on light levels and their interactions with known shade tolerances of tree species. Additionally, results were consistent with previously documented site disturbance effects on regeneration of residual and invader species, and shrub-tree competition and regeneration. These results permit prediction of the likely consequences for these 35-yr-old forest stands, and the thinned mature forest, of future, planned thinning treatments. Title: Thirty-five years of forest succession in southwest Oregon : vegetation response to three distinct logging treatments Author: Arthur, Aaron Stone This study examined patterns and controls on 35-years of forest succession following logging in the 236 ha South Umpqua Experimental Forest within the Umpqua National Forest in southwestern Oregon. Prior to logging, the overstory in all three watersheds (~50% cover) was composed of Douglas-fir (30-40% cover), grand fir (2 to 10% cover), incense cedar (2-4% cover), western hemlock (1-2 % cover), sugar pine (1-2% cover), ponderosa pine (0-1% cover), and madrone (0-1% cover). The sapling cover in all three watersheds (30-35% cover) was dominated by grand fir (15-20%), western hemlock (6-8% cover) incense cedar (3-5% cover), and Douglas-fir (3-5% cover), with <1% cover by the other tree species. In 1971, the overstory of the four watersheds received: WS-1 (69.2 ha) a 50% basal area removal (shelterwood); WS-2 (68.4 ha) 30% in 20 small clearcuts; WS-3 (49.8 ha) 100% clearcut; WS-4 (48.6 ha) uncut control. Prior to treatment, tree, shrub, and herb cover in WS 1-3 (n = 50 plots) was visually estimated using the reconnaissance survey method, but only WS 2-3 annually through 1981 (n = 39 plots). In 2006, plots were relocated and new plots added, and resurveyed (n = 77 plots). Plots were classified by environmental (aspect, slope, soil series, vegetation community) and disturbance factors (treatment, logging method, in-watershed location, and soil disturbance). Vegetation was classed into three groups: (1) vegetation structures; (2) overstory species; and (3) residual and invader understory species. Total vegetation cover decreased slightly over the 35-year period, with a slight decrease in shrubs, saplings, and herbs, and an increase in overstory tree cover in 2006 compared to 1971. Few statistically significant differences were observed in vegetation cover change according to environmental variables. However heavily disturbed sites were characterized by low shrub cover and high overstory cover, compared to lightly disturbed sites. These differences were still apparent 35 years after logging. Between 1971 and 2006 in WS-2 and WS-3, Douglas fir, incense cedar and ponderosa pine cover significantly increased, while other overstory species declined. In contrast, over the same period in WS-1, there was a significant change in grand fir and western hemlock cover. Sapling cover of all species stayed constant or declined in all watersheds, except Douglas-fir and western hemlock, which increased in WS-1 only. In the post-logging period, cover of ponderosa pine and Douglas fir cover was significantly higher on moderately and heavily disturbed plots compared to lightly disturbed plots. Before logging, residual species cover was significantly higher than invader species cover. Disturbance appeared to have the greatest effect upon the residual-invader species relationship. Residual species maintained higher cover on lightly disturbed plots, compared to invader species cover, which was highest on moderately and heavily disturbed plots. All species declined in WS-2 and WS-3 following stem exclusion. Overall patterns of tree, shrub, and herb cover succession over the 35-year post-logging period were consistent with the expected effects of clearcutting versus thinning on light levels and their interactions with known shade tolerances of tree species. Additionally, results were consistent with previously documented site disturbance effects on regeneration of residual and invader species, and shrub-tree competition and regeneration. These results permit prediction of the likely consequences for these 35-yr-old forest stands, and the thinned mature forest, of future, planned thinning treatments. Close

• 55. [Article] Prediction of peak flows for culvert design on small watersheds in Oregon

  Forest engineers must frequently make flood frequency estimates for very small watersheds when designing culvert installations. Empirical formulae and simplified rainfall runoff models, the most commonly ...

  Citation × Citation Citation Abstract Copy Title: Prediction of peak flows for culvert design on small watersheds in Oregon Author: Campbell, Alan J. Forest engineers must frequently make flood frequency estimates for very small watersheds when designing culvert installations. Empirical formulae and simplified rainfall runoff models, the most commonly used techniques to predict floods from very small watersheds, require considerable engineering judgement to give reasonable results. As an alternative to such methods, this study presents equations to predict peak flows on small watersheds in Oregon. The equations were developed from 80 watersheds ranging in size from 0.21 to 10.60 square miles. Oregon was divided into six physiographic regions based on previous flood frequency studies. In each region, annual peak flow data from gaging stations with more than 20 years of record were analyzed using four flood frequency distributions (Gumbel, two-parameter log-normal, three-parameter log-normal, log Pearson type III). The log Pearson type III distribution was found to be suitable for use in all regions of the state, based on the chi-square goodness of fit test. Flood magnitudes having recurrence intervals of 10, 25, 50, and 100 years were related to physical and climatic indices of drainage basins by multiple regression analysis. Drainage basin area (A) was the most important variable in explaining the variation of flood peaks in all regions. Mean basin elevation (E) and mean annual precipitation (P) were also significantly related to flood peaks in two regions in western Oregon. The following equations to predict the 25-year flood were developed for each physiographic region in Oregon: (1) Willamette region Q₂₅ = 156A·⁸⁰ (2) Coast region Q₂₅ = 6.31A¹⁰¹E·⁵¹ (3) Cascade region Q₂₅ = .O32A⁴⁴P¹·⁹⁷ (4) Rogue-Umpqua region Q₂₅ = l63A·⁷⁷ (5) Blue-Wallowa region Q₂₅ = 67.6A·⁴⁷ Title: Prediction of peak flows for culvert design on small watersheds in Oregon Author: Campbell, Alan J. Forest engineers must frequently make flood frequency estimates for very small watersheds when designing culvert installations. Empirical formulae and simplified rainfall runoff models, the most commonly used techniques to predict floods from very small watersheds, require considerable engineering judgement to give reasonable results. As an alternative to such methods, this study presents equations to predict peak flows on small watersheds in Oregon. The equations were developed from 80 watersheds ranging in size from 0.21 to 10.60 square miles. Oregon was divided into six physiographic regions based on previous flood frequency studies. In each region, annual peak flow data from gaging stations with more than 20 years of record were analyzed using four flood frequency distributions (Gumbel, two-parameter log-normal, three-parameter log-normal, log Pearson type III). The log Pearson type III distribution was found to be suitable for use in all regions of the state, based on the chi-square goodness of fit test. Flood magnitudes having recurrence intervals of 10, 25, 50, and 100 years were related to physical and climatic indices of drainage basins by multiple regression analysis. Drainage basin area (A) was the most important variable in explaining the variation of flood peaks in all regions. Mean basin elevation (E) and mean annual precipitation (P) were also significantly related to flood peaks in two regions in western Oregon. The following equations to predict the 25-year flood were developed for each physiographic region in Oregon: (1) Willamette region Q₂₅ = 156A·⁸⁰ (2) Coast region Q₂₅ = 6.31A¹⁰¹E·⁵¹ (3) Cascade region Q₂₅ = .O32A⁴⁴P¹·⁹⁷ (4) Rogue-Umpqua region Q₂₅ = l63A·⁷⁷ (5) Blue-Wallowa region Q₂₅ = 67.6A·⁴⁷ Close

• 56. [Article] Particulate organic matter export by two contrasting small mountainous rivers from the Pacific Northwest, U.S.A.

  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/jgr/.

  Citation × Citation Citation Abstract Copy Title: Particulate organic matter export by two contrasting small mountainous rivers from the Pacific Northwest, U.S.A. Author: Hatten, Jeff A., Goni, Miguel A., Borgeld, Jeffry C., Wheatcroft, Robert A. 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/jgr/. Title: Particulate organic matter export by two contrasting small mountainous rivers from the Pacific Northwest, U.S.A. Author: Hatten, Jeff A., Goni, Miguel A., Borgeld, Jeffry C., Wheatcroft, Robert A. 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/jgr/. Close

• 57. [Article] The ecological legacy of Indian burning practices in southwestern Oregon

  Two research questions are posed: (1) How have ecosystem conditions changed through time in southwestern Oregon? (2) How have culture-driven and climate-driven processes contributed to ecosystem change ...

  Citation × Citation Citation Abstract Copy Title: The ecological legacy of Indian burning practices in southwestern Oregon Author: Carloni, Kenneth R. Two research questions are posed: (1) How have ecosystem conditions changed through time in southwestern Oregon? (2) How have culture-driven and climate-driven processes contributed to ecosystem change in southwestern Oregon? A brief introduction to the Little River study area is followed by a cultural and ecological history of the watershed. Historical, ecological and archaeological data are used to describe shifts in landscape structure, stand structure and fire behavior. Changes in corridor/patch/matrix relationships, increases in stand densities, and changes in stand age and species structure are documented, and changes in fire dynamics from frequent to infrequent, and small to large are corroborated with descriptive statistics from the nearby 2002 Umpqua Fires. Hypotheses are then proposed to test the relative influence of humans vs. climate on landscape change during Aboriginal (<1820) vs. Euroagrarian (1850-1950) cultural phases. While precipitation shows no correlation with fire frequency or tree recruitment before 1820, significant associations are observed from 1850 to 1950. Moreover, a significant correlation exists between fire frequency and subsequent tree recruitment after 1850, but is not observed during aboriginal times. This suggests that indigenous management fires may have obscured precipitation influences that become apparent only after 1850. In order to test spatial hypotheses concerning the associations between indigenous humans and the landscape, archaeological sites were digitized into a GIS, and ergonomic pathways were modeled between them. These maps are then compared to historically fire-maintained upland meadows interpreted from 1946 aerial photos. A significant spatial correlation was found between archaeological sites and historic meadows, and a highly significant spatial correlation was found between modeled travel networks and historic meadows. The close spatial association between cultural features and fire-maintained habitats again suggests active landscape management by local Indians. These associations are corroborated with historical records. After summarizing the shifts in ecological conditions and describing current conditions, I argue that while restoring the landscape to aboriginal conditions is no longer possible, emulating those conditions within the framework of the Little River Adaptive Management Area Plan can improve the resilience and productivity of the Little River watershed. Title: The ecological legacy of Indian burning practices in southwestern Oregon Author: Carloni, Kenneth R. Two research questions are posed: (1) How have ecosystem conditions changed through time in southwestern Oregon? (2) How have culture-driven and climate-driven processes contributed to ecosystem change in southwestern Oregon? A brief introduction to the Little River study area is followed by a cultural and ecological history of the watershed. Historical, ecological and archaeological data are used to describe shifts in landscape structure, stand structure and fire behavior. Changes in corridor/patch/matrix relationships, increases in stand densities, and changes in stand age and species structure are documented, and changes in fire dynamics from frequent to infrequent, and small to large are corroborated with descriptive statistics from the nearby 2002 Umpqua Fires. Hypotheses are then proposed to test the relative influence of humans vs. climate on landscape change during Aboriginal (<1820) vs. Euroagrarian (1850-1950) cultural phases. While precipitation shows no correlation with fire frequency or tree recruitment before 1820, significant associations are observed from 1850 to 1950. Moreover, a significant correlation exists between fire frequency and subsequent tree recruitment after 1850, but is not observed during aboriginal times. This suggests that indigenous management fires may have obscured precipitation influences that become apparent only after 1850. In order to test spatial hypotheses concerning the associations between indigenous humans and the landscape, archaeological sites were digitized into a GIS, and ergonomic pathways were modeled between them. These maps are then compared to historically fire-maintained upland meadows interpreted from 1946 aerial photos. A significant spatial correlation was found between archaeological sites and historic meadows, and a highly significant spatial correlation was found between modeled travel networks and historic meadows. The close spatial association between cultural features and fire-maintained habitats again suggests active landscape management by local Indians. These associations are corroborated with historical records. After summarizing the shifts in ecological conditions and describing current conditions, I argue that while restoring the landscape to aboriginal conditions is no longer possible, emulating those conditions within the framework of the Little River Adaptive Management Area Plan can improve the resilience and productivity of the Little River watershed. Close

• 58. [Article] Wolf Creek Monitoring

  Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR.

  Citation × Citation Citation Abstract Copy Title: Wolf Creek Monitoring Author: Dammann, Daniel Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR. Title: Wolf Creek Monitoring Author: Dammann, Daniel Presented at The Oregon Water Conference, May 24-25, 2011, Corvallis, OR. Close

• 59. [Article] Summertime water temperature trends in Steamboat Creek Basin, Umpqua National Forest

  The Steamboat Creek basin drains 227 mi² (588 km²) of steep forested terrain into the North Umpqua River of Southwest Oregon, 39 mi (63 km) northeast of Roseburg. Summer base flows for Steamboat Creek ...

  Citation × Citation Citation Abstract Copy Title: Summertime water temperature trends in Steamboat Creek Basin, Umpqua National Forest Author: Holaday, Steven A. The Steamboat Creek basin drains 227 mi² (588 km²) of steep forested terrain into the North Umpqua River of Southwest Oregon, 39 mi (63 km) northeast of Roseburg. Summer base flows for Steamboat Creek average 83 cfs (2.35 m³/sec). Steamboat Creek and its tributaries are considered important to the production of summer-run steelhead; the basin has been closed to angling since 1932. Harvesting has occurred in every subdrainage of the Steamboat Creek basin. Trees were routinely removed from riparian areas when harvesting in the basin began in 1955. Since the mid-1970s to early-1980s, however, buffer strips were left adjacent to streams. In addition, the floods of 1964-65 caused significant damage to riparian vegetation in the basin. This study was undertaken to: (1) determine long-term trends over the period 1969-90 of summertime water temperatures in the mainstem of Steamboat Creek, selected tributaries, and in Boulder Creek, an unharvested control stream in an adjacent watershed and (2) evaluate spacial patterns of maximum water temperatures in the Steamboat Creek basin during the summer of 1990. Significant (P≤0.10) trends of decreasing maximum daily summertime stream temperatures on Steamboat Creek and tributaries occurred from 1969-90. In contrast, an unharvested control stream showed a small, but nonsignificant, increasing trend in stream temperatures. The largest decrease in maximum stream temperatures (7 to 11°F, 3.9 to 6.1°C) occurred on small streams with summer base flows less than 6 cfs (0.17 m³/sec). These streams also had the highest proportion of stream length adjacent to harvesting activities before 1974. The smallest decrease in maximum stream temperatures (0 to 3°F, 0 to 1.7°C) occurred on streams with little or no history of timber harvest activity along riparian areas, or at locations where summer base flows were greater than 15 cfs (0.42 m³/sec). Since no trends in either air temperature or streamflow were apparent over the 1969-90 period, regrowth of riparian vegetation that was previously removed by flooding, debris torrents, or streamside harvesting, appears to be the major cause of trends in decreasing maximum summer stream temperature. Regrowth of riparian vegetation provides shade over small streams, decreasing energy input to the stream from solar radiation. Maximum daily stream temperatures in lower Steamboat Creek did not change significantly during the 1969-90 study period and stream temperature data in 1960 indicates that maximum stream temperatures in lower Steamboat Creek have historically been high. Any cooling effects by groundwater or tributaries are largely negated by the large volume of water in the main channel. Also, the large stream width renders riparian vegetation relatively ineffective in protecting the stream from solar radiation. Minimum stream temperatures decreased during the 1969-90 study period for all of the long-term stations in the Steamboat Creek basin while the control stream showed a slight increasing trend. Similarly, diurnal stream temperature fluctuations decreased for several tributaries. Title: Summertime water temperature trends in Steamboat Creek Basin, Umpqua National Forest Author: Holaday, Steven A. The Steamboat Creek basin drains 227 mi² (588 km²) of steep forested terrain into the North Umpqua River of Southwest Oregon, 39 mi (63 km) northeast of Roseburg. Summer base flows for Steamboat Creek average 83 cfs (2.35 m³/sec). Steamboat Creek and its tributaries are considered important to the production of summer-run steelhead; the basin has been closed to angling since 1932. Harvesting has occurred in every subdrainage of the Steamboat Creek basin. Trees were routinely removed from riparian areas when harvesting in the basin began in 1955. Since the mid-1970s to early-1980s, however, buffer strips were left adjacent to streams. In addition, the floods of 1964-65 caused significant damage to riparian vegetation in the basin. This study was undertaken to: (1) determine long-term trends over the period 1969-90 of summertime water temperatures in the mainstem of Steamboat Creek, selected tributaries, and in Boulder Creek, an unharvested control stream in an adjacent watershed and (2) evaluate spacial patterns of maximum water temperatures in the Steamboat Creek basin during the summer of 1990. Significant (P≤0.10) trends of decreasing maximum daily summertime stream temperatures on Steamboat Creek and tributaries occurred from 1969-90. In contrast, an unharvested control stream showed a small, but nonsignificant, increasing trend in stream temperatures. The largest decrease in maximum stream temperatures (7 to 11°F, 3.9 to 6.1°C) occurred on small streams with summer base flows less than 6 cfs (0.17 m³/sec). These streams also had the highest proportion of stream length adjacent to harvesting activities before 1974. The smallest decrease in maximum stream temperatures (0 to 3°F, 0 to 1.7°C) occurred on streams with little or no history of timber harvest activity along riparian areas, or at locations where summer base flows were greater than 15 cfs (0.42 m³/sec). Since no trends in either air temperature or streamflow were apparent over the 1969-90 period, regrowth of riparian vegetation that was previously removed by flooding, debris torrents, or streamside harvesting, appears to be the major cause of trends in decreasing maximum summer stream temperature. Regrowth of riparian vegetation provides shade over small streams, decreasing energy input to the stream from solar radiation. Maximum daily stream temperatures in lower Steamboat Creek did not change significantly during the 1969-90 study period and stream temperature data in 1960 indicates that maximum stream temperatures in lower Steamboat Creek have historically been high. Any cooling effects by groundwater or tributaries are largely negated by the large volume of water in the main channel. Also, the large stream width renders riparian vegetation relatively ineffective in protecting the stream from solar radiation. Minimum stream temperatures decreased during the 1969-90 study period for all of the long-term stations in the Steamboat Creek basin while the control stream showed a slight increasing trend. Similarly, diurnal stream temperature fluctuations decreased for several tributaries. Close

• 60. [Article] Trees, snow and flooding: an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest

  Concerns about the extent to which major Pacific Northwest floods over the last decade might have been exacerbated by logging have heightened the need for a better scientific understanding of the role ...

  Citation × Citation Citation Abstract Copy Title: Trees, snow and flooding: an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest Author: Storck, Pascal Concerns about the extent to which major Pacific Northwest floods over the last decade might have been exacerbated by logging have heightened the need for a better scientific understanding of the role of forest maturity on snow accumulation and melt. To address this need, a multi-scale field and modeling study of the effects of forest canopies on snow accumulation and melt was conducted. Over a three year period, weighing lysimeters and cut-tree experiments were used to measure the process controlling snow interception and its fate at a site in the Umpqua National Forest, OR (elevation 1200 m). Continuous observations of below-canopy snowpack evolution were made over the same period. Over the study period, approximately 60 percent of annual snowfall was intercepted by the canopy (up to a maximum of 40 mm water equivalent). Approximately 72 percent and 28 percent of the intercepted snow was removed as meltwater drip and large snow masses, respectively. Apparent average sublimation rates from the intercepted snow were less than 1 mm per day and totaled approximately 100 mm per winter season. Title: Trees, snow and flooding: an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest Author: Storck, Pascal Concerns about the extent to which major Pacific Northwest floods over the last decade might have been exacerbated by logging have heightened the need for a better scientific understanding of the role of forest maturity on snow accumulation and melt. To address this need, a multi-scale field and modeling study of the effects of forest canopies on snow accumulation and melt was conducted. Over a three year period, weighing lysimeters and cut-tree experiments were used to measure the process controlling snow interception and its fate at a site in the Umpqua National Forest, OR (elevation 1200 m). Continuous observations of below-canopy snowpack evolution were made over the same period. Over the study period, approximately 60 percent of annual snowfall was intercepted by the canopy (up to a maximum of 40 mm water equivalent). Approximately 72 percent and 28 percent of the intercepted snow was removed as meltwater drip and large snow masses, respectively. Apparent average sublimation rates from the intercepted snow were less than 1 mm per day and totaled approximately 100 mm per winter season. Close