Natural lake-watershed ecosystems in Oregon compose a diverse and valuable assemblage of land and water resources. With an increasing demand on lakes for recreation, water supplies, and aesthetic values and an increase in available data on Oregon lake systems, there is a need for applicable and timely scientific water management information about lake conditions statewide. This thesis is an attempt to summarize some of the data collected on natural Oregon lake-watershed ecosystems. The purpose of the thesis is to identify the most typical natural systems out of an initial data base of twenty-four variables, measured over ninety-eight lake-watershed ecosystems. The selected variables are reduced to five common factors using principal components factor analysis. K-means cluster analysis is used to create similar groups of lake systems. These groups are compared to ecoregions in Oregon and a typical, representative lake ecosystem is identified for each group. Results show that several lake systems of the state are unique.

The foraminiferal population of Yaquina Bay was investigated to attempt a correlation of seasonal changes in the hydrography with observed changes in the faunal distribution patterns. The results are based on data from two spatial surveys conducted in July 1966, and late February and March, 1967. The hydrography of Yaquina Bay undergoes seasonal changes closely paralleling the seasonal precipitation pattern. Except for short-term variations, the estuarine system is partly-mixed during the period of maximum river discharge (November to May) and wellmixed from June through October. Coastal upwelling (high salinity, low temperature) has a marked influence on the hydrography of the lower bay during the summer; maximum salinities and temperatures prevail in the upper reaches of the estuary during late summer and fall. Species associations were determined by the Fager-McConnaughey correlation coefficient method; similar assemblages were found for both summer and winter surveys. A marine biofacies fauna, dominated by Elphidium microgranulosum and E. frigidum, occupies the main estuary channel for about five miles upstream. The distributional patterns of the living fauna show evidence of a stronger marine influence during the summer, corresponding to a similar pattern in the hydrography. In the lower bay, the Elphidium fauna is displaced laterally by an assemblage characterized by Trochammina charlottensis and Elphidium incertum in the middle intertidal zone. This assemblages in turn gives way to an Ammobaculites exiguus -Miliammina fusca fauna in the upper intertidal area. The Elphidium assemblage gives way to a Miliammina fauna in the upstream direction. Trochammina inflata, T. macrescens, Miliammina fusca, Jadamminina polystoma, Haplophragmoides sp., H. hancocki and Siphotrochammina lobata are the principal species found in the marine marsh. Zones of environmental similarity were defined by the index of affinity association analysis. Living and total faunas of both winter and summer surveys were considered separately; several sample groups were defined in each case. Index of affinity data can also be used to provide an index of the marine influence on the foraminiferal population of the estuary. Species diversity or the average number of species/sample, ranges from 22 in the marine biofacies zone to six on the lower bay tideflats. An intermediate value (l0/sample)was found for the marine marsh. Highest standing crops were found in the marshes (summer) and on the tideflats adjacent to the lower bay channel, averaging 40 and 42/cm² respectively. Lowest values (1 to 2 cm²) were found in the middle to upper intertidal areas of the lower bay during the summer. The distribution of the total fauna is quite similar to that of the living population. Highest average values (175/cm³) are again found in the marine marsh and in the marine biofacies zone (70 to 80/cm³). Lowest values occur on the lower bay intertidal areas (3 to 9/cm³). In general, the percentage representation of agglutinated species in the total fauna increases with distance upstream in the channel and with distance laterally from the channel axis. Faunas of some marsh stations are composed entirely of agglutinated species. The percentage of calcareous hyaline species shows an inverse relation to that of the agglutinated fauna, increasing in importance with approach to marine conditions. Porcelaneous and planktonic species are generally minor constituents in the total fauna and are restricted to the marine biofacies as it is developed in the estuary. Foraminifer-ostracod ratios are extremely variable in the environments sampled in Yaquina Bay. Smooth-valved species are characteristic of the marine marsh and inner bay environments; valve ornamentation tends to increase with approach to marine conditions. Thecamoebians are present in low numbers throughout the estuary. In general however, the number of species and population size increases in the upstream direction. / Graduation date: 1968

Recent research has indicated that dissolved organic matter (DOM) may plan an important role in the ability of natural waters to complex metals. This research was conducted because the quantitative nature of this role is uncertain. Gas-liquid chromatography was used to study the hydrolyzable amino acids at twelve sampling sites on the Williamson River at monthly intervals for two years. The relative abundances showed little spacial or temporal variation. The two-year averages for total amino acids ranged from about 0.5 (mu)M to about 8 (mu)M. A separation technique was used to show that (GREATERTHEQ) 96% of the dissolved amino acids were associated with aquatic humus. Since it was found that amino acids contributed less than 1% to humic carbon and since a published report found that carbohydrates contributed less than 2% to humic carbon, this research provided the necessary data to conclude that DOM in the Williamson River is essentially aquatic humus. Humus complexation capacity is often operationally defined as amount of metal bound per unit weight of humus. This research has shown that the titrimetric methods commonly used to obtain this parameter underestimate its magnitude. However, it was shown that these methods can be combined with acidic functional group analyses to determine upper and lower limit for this parameter. For Williamson River humus, the range was 7.2 - 15.4 (mu)mols copper per mg humic carbon. Titrations of humus into a copper-oxalate metal-ion buffer enabled the determination of the copper-humus binding "constant" at humas : copper ratios found in the Williamson River, (LESSTHEQ) 4300. The binding "constant" was a variable and a function of pH. At a humus: copper ratio of 4300, the values of the function at pH 5.0, 5.5, 6.0, and 6.5 were: 3.0 x 10('6), 8.9 x 10('6), 3.0 x 10('7), and 1.7 x 10('8). Current models of metal-humus complexation, were shown to be inappropriate via rigorous mathematical examination and via application to computer-simulated titrations. A model, in which it is assumed that the concentrations of binding sites in humus are normally distributed with respect to the log of the metal binding constant for each site, is proposed. Application of this model to simulated titrations and to experimental data proved it to be superior to other current models.

Current research indicates that the expansion of western juniper can inhibit soil water retention, storage and prolonged releases from watersheds. This phenomenon is of great importance in eastern Oregon, as western juniper is encroaching into sagebrush/grass communities with a correlated reduction in herbaceous ground cover, resulting in reduced infiltration rates and increased soil loss. A paired watershed study for the purpose of monitoring water quality/quantity as affected by western juniper in the Camp Creek drainage, a tributary to the Crooked River, was established in 1994. Monitoring methods consisted of annual and semiannual measurements of hillslope soil movement, channel morphology, including total cross-sectional area, scour and deposition, channel discharge, depth to groundwater, and precipitation. Channel discharge was established using a 3,0 H-flume with a pressure transducer and stilling well and data logger. Changes in channel morphology were determined using 25 permanent, channel cross-section plots per watershed. Hillslope erosion processes were determined using 12 transects of 3 sediment stakes per watershed, located within gullies of subwatersheds. Data showed the two study areas to be well correlated with regards to soil movement, both within the main channels and in the subwatersheds (hillslopes). Some of the geomorphometric properties are similar (not statistically different) and differences in other parameters can be explained. Channel discharge appears to be significantly different in intensity, frequency, and duration of flow. These differences in surface discharge may be explained as further data collection of subsurface flow analysis in conjunction with sampling of springs located in each watershed are conducted. / Graduation date: 2005

This study assessed how logging-access roads may have contributed to observed historical increases in peak discharges associated with small and large logged basins in the western Cascades of Oregon. The study was conducted on the Lookout Creek (62km��) and the upper Blue River (118km��) basins. Potential road effects on hydrology were examined using a combination of field surveys and spatial modeling with a geographic information system (GIS). Road networks were similar in both basins with respect to hillslope position, orientation, and stream crossings, but roads in Blue River were constructed one or two decades later than roads in Lookout Creek. A total of 20% (62 km) of the road length was sampled to assess routing of surface flow, using 31 2-km transects stratified by decade of construction and hillslope position. Along each transect, ditches and culvert outlets were examined and this information used to predict the probable routing of water to (1) existing stream channels, (2) newly eroded gullies downslope of culvert outlets, or (3) subsurface flow. Nearly 60% of the surveyed road length appeared to route water directly to stream channels or into gullies. Over time, the length of road connected to stream crossings has decreased, while the length of road discharging runoff that reinfiltrates to subsurface flow has increased, as roads have progressed up hillslopes and onto ridges in Lookout Creek and Blue River. The relatively constant proportion of the road network draining to gullies over time suggests that roads have the potential to become integrated into stream networks, even when constructed on unchannelled hillslope positions. An extended stream network, assumed to exist under storm conditions, was simulated for the basins using a digital elevation model. Although gullies and ditches differ from natural channels, extrapolation of field surveys using the GIS suggested that roads might extend the stream network by as much as 40% during storm events. It is hypothesized that such an effect could decrease the time of concentration of stormflow and contribute to higher peak discharges observed after clearcutting and road construction in these basins. Differences in the magnitude of road effects on peak flow generation may occur among road systems according to hillslope position of roads, road age, soil saturation, geologic substrate, and climate. These differences may explain the range of observed results from paired-basin studies examining road effects on hydrologic response. / Graduation date: 1994

Climate changes brought on by global warming are expected to have a significant affect on the Pacific Northwest hydrology during the 21st Century. Current research anticipates higher mean annual temperatures and an intensification of the hydrological cycle. This is of particular concern for highly urbanized basins, which are considered more vulnerable to changes in climate. Because the majority of previous studies have addressed the influences of either climate or urban land cover changes on runoff, there is a lack of research investigating the combined effect of these factors. The Rock Creek basin (RCB), located in the Portland, OR, metropolitan area, has been experiencing rapid urban growth throughout the last 30 years, making it an ideal study area for assessing the affect of climate and land cover changes on runoff. Methods for this assessment include using a combination of climate change and land cover change scenarios for 2040 with the semi distributed AVSWAT-X (Arc View Soil and Water Assessment Tool) hydrological model to determine changes in mean runoff depths at the monthly, seasonal, and annual scales. Statistically downscaled climate change results from the ECHAM5 general circulation model (GCM) found that the region would experience an increase of 1.2°C in the average annual temperature and a 6% increase in average annual precipitation between 2030 and 2059. The model results revealed an amplification of runoff from either climate or urbanization. Projected climate change plus low-density, sprawled urban development for 2040 produced the greatest change to mean annual runoff depth (+5.5%), while climate change plus higher-density urban development for 2040 resulted in the smallest change (+5.3%), when compared to the climate and land cover of 2001. The results of this study support the hypothesis that the combination of both climate change and urbanization would amplify the runoff from the RCB during the 21st Century. This has significant implications for water resource managers attempting to implement adaptive water resource policies to future changes resulting from climate and urbanization.

Transitional areas between upland and aquatic habitats, commonly known as wetland, were once viewed as unproductive areas and were drained for farming or pasture. Wetlands are now accepted as significant ecological resources, and their protection is a mandate of federal, state, and local land managers. Due to the diversity of wetland areas, the appropriate assessment of wetland resources cannot be accomplished without long term monitoring of wetland functions. Knowledge of the duration of saturation and associated anaerobic conditions of soils in wetlands is critical to correctly classify and assess wetland areas. Soil, hydrological, and biogeochemical characteristics of the soils of the Jackson-Frazier wetland were observed from October 1992 through March 1994. Weekly observations of water levels and redox potential at depths of 25, 50, and 100 cm were made in order to characterize the degree and duration of saturation and the anaerobic conditions in the soil over time. Permanently installed piezometers measured free water in the soil and indicated the presence of two separated water tables from the onset of the rainy season in October until February when the entire soil profile became saturated with free water. Platinum electrodes measured redox potential in the soil and indicated anaerobic conditions for ten months during the first season of observation and through March of the second season. Anaerobic conditions were considered to be achieved when Fe����� was reduced to Fe����� at a potential of 200 millivolts. The highly reducing conditions correspond to periods of soil saturation indicated by piezometers. Concentrations of iron and manganese observed in soil profiles correspond to conditions of prolonged saturation and reduction confirmed by monitoring. A soil stratigraphic study done with auger holes revealed a recent alluvial deposit of montmorrillonitic clay overlying lacustrine silts identified as the Irish Bend Member of the Willamette Formation. The clay deposit overlying the surface of the wetland acts as an aquitard and creates extensive surface ponding, which maintains the saturated habitat required for wetland vegetation. The subsurface hydrology is controlled by water flowing through the Irish Bend silts which results in saturation of the soils from below. Biogeochemical transformations of iron and manganese due to suboxic and anaerobic conditions are controlled by this type of soil saturation in the Jackson-Frazier wetland. / Graduation date: 1995

This dissertation integrates a process-based hydrological investigation with an ongoing paired-catchment study to better understand how forest harvest impacts catchment function at multiple scales. We do this by addressing fundamental questions related to the stocks, flows and transit times of water. Isotope tracers are used within a top-down catchment intercomparison framework to investigate the role of geology in controlling streamwater mean transit time and their scaling relationships with the surrounding landscape. We found that streams draining catchments with permeable bedrock geology at the Drift Creek watershed in the Oregon Coast Range had longer mean transit times than catchments with poorly permeable bedrock at the HJ Andrews Experimental Forest in the Oregon Cascades. We also found that differences in permeability contrasts within the subsurface controlled whether mean transit time scaled with indices of catchment topography (for the poorly permeable bedrock) or with catchment area (for the permeable bedrock). We then investigated the process-reasons for the observed differences in mean transit time ranges and scaling behavior using a detailed, bottom-up approach to characterize subsurface water stores and fluxes. We found that the mean transit times in catchments underlain by permeable bedrock were influenced by multiple subsurface storage pools with different groundwater ages, whereas storage in the poorly permeable catchments was limited to the soil profile and that resulted in quick routing of excess water to the stream at the soil bedrock interface, leading to mean transit times that were closely related to flowpath lengths and gradients. Finally, we examined how and where forest trees interacted with subsurface storage during the growing season using a forest manipulation experiment, where we tested the null hypothesis that near-stream trees alone influenced daily fluctuations in streamflow. We felled trees within this zone for two 2.5 ha basins and combined this with isotopic tracing of tree xylem water to test if water sources utilized by trees actively contributed to summer streamflow. We rejected our null hypotheses and found that diel fluctuations in streamflow were not generated exclusively in the near-stream zone. We were unable to link, isotopically, the water sources trees were utilizing to water that was contributing to streamflow. Our results provide new process-insights to how water is stored, extracted, and discharged from our forested catchments in Western Oregon that will help better explain how forest removal influences streamflow across multiple scales and geological conditions. / Graduation date: 2012

This study compared two remote sensing water indices: the Normalized Difference Water Index (NDWI) and the Modified NDWI (MNDWI). Both indices were calculated using publically-available data from the Landsat 8 Operational Land Imager (OLI). The research goal was to determine whether the indices are effective in locating open water and measuring surface soil moisture. To demonstrate the application of water indices, analysis was conducted for freshwater wetlands in the Tualatin River Basin in northwestern Oregon to estimate hydrologic connectivity and hydrological permanence between these wetlands and nearby water bodies. Remote sensing techniques have been used to study wetlands in recent decades; however, scientific studies have rarely addressed hydrologic connectivity and hydrologic permanence, in spite of the documented importance of these properties. Research steps were designed to be straightforward for easy repeatability: 1) locate sample sites, 2) predict wetness with water indices, 3) estimate wetness with soil samples from the field, 4) validate the index predictions against the soil samples from the field, and 5) in the demonstration step, estimate hydrologic connectivity and hydrological permanence. Results indicate that both indices predicted the presence of large, open water features with clarity; that dry conditions were predicted by MNDWI with more subtle differentiation; and that NDWI results seem more sensitive to sites with vegetation. Use of this low-cost method to discover patterns of surface moisture in the landscape could directly improve the ability to manage wetland environments.

In the Portland, Oregon, metropolitan area, suburban cities such as Hillsboro are projected to grow as people seek affordable housing near a rapidly growing metropolis. This thesis examines the combined impact of'c1imate change and urban development on both neighborhood and municipal scale residential water demand in Hillsboro, Oregon. I use two models, a surface energy balance model, Local-scale Urban Meteorological Parameterization Scheme (LUMPS), and a system dynamics model, CCDomestic, to investigate changes in residential water demand in the 2040s at two distinct spatial scales, the neighborhood and the municipality. I calibrate and validate each model to the reference period and then simulate the future (2030-2059) under three statistically downscaled global climate models and two urban development scenarios. The findings of this study indicate that climate change and urban development will not evenly affect water consumption in neighborhoods across a city. Instead, the current land cover and residential density of a neighborhood exert an important influence on the response. Heavily vegetated neighborhoods exhibit large increases in water demand under urban sprawl and warming scenarios, while neighborhoods dominated by impervious surfaces decrease water consumption under sprawl scenarios and show little change in water consumption under combined sprawl and warming scenarios. At the municipal scale findings suggest that water demand is highly sensitive to urban design and management and that the combination of urban densification and water conservation regulations could mitigate increases in water consumption from population growth and climate change.