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• 1. [Article] Investigations into the Regional and Local Timescale Variations of Subglacial Drainage Networks

  Subglacial water plays an important role in the regulation of an ice sheet's mass balance. It may be the dominant control on the velocities of ice streams and outlet glaciers on scales of months to millennia. ...

  Citation × Citation Citation Abstract Copy Title: Investigations into the Regional and Local Timescale Variations of Subglacial Drainage Networks Author: Hiester, Justin Year: 2013 Subglacial water plays an important role in the regulation of an ice sheet's mass balance. It may be the dominant control on the velocities of ice streams and outlet glaciers on scales of months to millennia. Recent satellite observations of ice surface elevation changes have given researchers new insights into how subglacial water is stored and transported. Localized uplift and settling of the ice surface implies that lakes exist beneath the ice sheet that are being filled and drained on relatively short time scales. %At the base of an ice sheet water can be transported through a variety of drainage networks or stored in subglacial lakes. Here, a numerical investigation of the mechanisms of transport and storage of subglacial water and the associated time scales is presented. Experiments are carried out using a finite element model of coupled ice and water flow. The first experiment seeks to understand the relationship between the depth of a basal depression and the area over which the feature affects basal water flow. It is found that as the perturbation to a topographic depression's depth is increased, water is rerouted in response to the perturbation. Additionally it is found that the relationship between perturbation depth and the extent upstream to which its effects reach is nonlinear. The second experiment examines how the aspect ratio of bed features (prolate, oblate, or equidimensional) influences basal water flow. It is found that the systems that develop and their interactions are mediated by both the topography and the feedbacks taken into account by the coupling of the systems in the model. Features oriented parallel to ice and water flow are associated with distributed fan systems that develop branches which migrate laterally across the domain and interact with one another on monthly and yearly timescales. Laterally oriented features develop laterally extensive ponds. As the ratio of longitudinal to lateral dimension of the topography is increased, a combination of these two water distributions is seen. Title: Investigations into the Regional and Local Timescale Variations of Subglacial Drainage Networks Author: Hiester, Justin Year: 2013 Subglacial water plays an important role in the regulation of an ice sheet's mass balance. It may be the dominant control on the velocities of ice streams and outlet glaciers on scales of months to millennia. Recent satellite observations of ice surface elevation changes have given researchers new insights into how subglacial water is stored and transported. Localized uplift and settling of the ice surface implies that lakes exist beneath the ice sheet that are being filled and drained on relatively short time scales. %At the base of an ice sheet water can be transported through a variety of drainage networks or stored in subglacial lakes. Here, a numerical investigation of the mechanisms of transport and storage of subglacial water and the associated time scales is presented. Experiments are carried out using a finite element model of coupled ice and water flow. The first experiment seeks to understand the relationship between the depth of a basal depression and the area over which the feature affects basal water flow. It is found that as the perturbation to a topographic depression's depth is increased, water is rerouted in response to the perturbation. Additionally it is found that the relationship between perturbation depth and the extent upstream to which its effects reach is nonlinear. The second experiment examines how the aspect ratio of bed features (prolate, oblate, or equidimensional) influences basal water flow. It is found that the systems that develop and their interactions are mediated by both the topography and the feedbacks taken into account by the coupling of the systems in the model. Features oriented parallel to ice and water flow are associated with distributed fan systems that develop branches which migrate laterally across the domain and interact with one another on monthly and yearly timescales. Laterally oriented features develop laterally extensive ponds. As the ratio of longitudinal to lateral dimension of the topography is increased, a combination of these two water distributions is seen. Close

• 2. [Article] Examining the Effects of Climate Change and Urban Development on Water Demand: A Multi-Scale Analysis of Future Water Demand in Hillsboro, Oregon

  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 ...

  Citation × Citation Citation Abstract Copy Title: Examining the Effects of Climate Change and Urban Development on Water Demand: A Multi-Scale Analysis of Future Water Demand in Hillsboro, Oregon Author: House-Peters, Lily Year: 2010 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. Title: Examining the Effects of Climate Change and Urban Development on Water Demand: A Multi-Scale Analysis of Future Water Demand in Hillsboro, Oregon Author: House-Peters, Lily Year: 2010 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. Close

• 3. [Article] A Comparison of Five Models for Estimating Clear-Sky Solar Radiation

  Many agencies in the USA are developing management approaches to address water quality concerns and threatened and endangered species habitat requirements in water bodies. Many of these water bodies are ...

  Citation × Citation Citation Abstract Copy Title: A Comparison of Five Models for Estimating Clear-Sky Solar Radiation Author: Annear, Robert Leslie, Wells, Scott A. Year: 2007 Many agencies in the USA are developing management approaches to address water quality concerns and threatened and endangered species habitat requirements in water bodies. Many of these water bodies are water quality limited for temperature. Factors influencing stream temperature include: streamside vegetation, topographic shading, inflows and outflows, stream width, stream depth, light extinction and solar radiation. One of the key driving factors in estimating a water body heat budget is calculating the amount of solar radiation incident on the water surface. Even though it is preferable to measure clear-sky solar radiation, many temperature models rely on theoretical estimates of clear-sky solar radiation. The literature on estimating short-wave solar radiation by calculating the position of the sun and attenuating the radiation through the atmosphere was reviewed. As a first step in relating water temperature to solar radiation, several empirical solar radiation models were calibrated to data at seventeen sites around the United States for clear-sky days. Sensitivity analyses were conducted and differences between the models were examined. Results indicated that the more complex models for calculating solar radiation resulted in better estimates of clear-sky solar radiation once they were calibrated to data. When no data were available, models with one or no calibration parameters did reasonably well at estimating clear-sky solar radiation. Title: A Comparison of Five Models for Estimating Clear-Sky Solar Radiation Author: Annear, Robert Leslie, Wells, Scott A. Year: 2007 Many agencies in the USA are developing management approaches to address water quality concerns and threatened and endangered species habitat requirements in water bodies. Many of these water bodies are water quality limited for temperature. Factors influencing stream temperature include: streamside vegetation, topographic shading, inflows and outflows, stream width, stream depth, light extinction and solar radiation. One of the key driving factors in estimating a water body heat budget is calculating the amount of solar radiation incident on the water surface. Even though it is preferable to measure clear-sky solar radiation, many temperature models rely on theoretical estimates of clear-sky solar radiation. The literature on estimating short-wave solar radiation by calculating the position of the sun and attenuating the radiation through the atmosphere was reviewed. As a first step in relating water temperature to solar radiation, several empirical solar radiation models were calibrated to data at seventeen sites around the United States for clear-sky days. Sensitivity analyses were conducted and differences between the models were examined. Results indicated that the more complex models for calculating solar radiation resulted in better estimates of clear-sky solar radiation once they were calibrated to data. When no data were available, models with one or no calibration parameters did reasonably well at estimating clear-sky solar radiation. Close

• 4. [Article] Continuous Deflection Separation of Stormwater Particulates

  Capture of stormwater particulate matter is of concern to watershed managers trying to meet water quality guidelines by removing toxics associated with particulates from natural water bodies. A laboratory ...

  Citation × Citation Citation Abstract Copy Title: Continuous Deflection Separation of Stormwater Particulates Author: Schwarz, Tracy S., Wells, Scott A. Year: 1999 Capture of stormwater particulate matter is of concern to watershed managers trying to meet water quality guidelines by removing toxics associated with particulates from natural water bodies. A laboratory investigation into particle removal efficiency of a prototype Continuous Deflective Separation (CDS) device was made in the laboratory. Particle size distributions were obtained for roadway drainage surfaces. These distributions were used to assess the predicted performance of a CDS unit in the field. Flow rates in the laboratory tests ranged from 125 GPM (7.9 l/s) to 270 GPM (17.0 l/s). Screen sizes used for testing were 1200 m and 2400 m. Using four different sand types and the two screen sizes, particle capture rates were determined for the CDS unit. Internal velocities were measured at seventy-two measuring positions within the main chamber of the CDS unit. At 270 GPM capture rates based on particle size ranged from 12% to 100% with the 2400 m screen, and 22% to 100% with the 1200 m screen. Cumulative mass capture rates were 73% and 70% for the 1200 m and 2400 m screens, respectively, at 270 gpm and 84% at 125 gpm for the given particle distribution used. Title: Continuous Deflection Separation of Stormwater Particulates Author: Schwarz, Tracy S., Wells, Scott A. Year: 1999 Capture of stormwater particulate matter is of concern to watershed managers trying to meet water quality guidelines by removing toxics associated with particulates from natural water bodies. A laboratory investigation into particle removal efficiency of a prototype Continuous Deflective Separation (CDS) device was made in the laboratory. Particle size distributions were obtained for roadway drainage surfaces. These distributions were used to assess the predicted performance of a CDS unit in the field. Flow rates in the laboratory tests ranged from 125 GPM (7.9 l/s) to 270 GPM (17.0 l/s). Screen sizes used for testing were 1200 m and 2400 m. Using four different sand types and the two screen sizes, particle capture rates were determined for the CDS unit. Internal velocities were measured at seventy-two measuring positions within the main chamber of the CDS unit. At 270 GPM capture rates based on particle size ranged from 12% to 100% with the 2400 m screen, and 22% to 100% with the 1200 m screen. Cumulative mass capture rates were 73% and 70% for the 1200 m and 2400 m screens, respectively, at 270 gpm and 84% at 125 gpm for the given particle distribution used. Close

• 5. [Article] CE-QUAL-W2, Version 3

  CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified ...

  Citation × Citation Citation Abstract Copy Title: CE-QUAL-W2, Version 3 Author: Wells, Scott A., Cole, Thomas M. Year: 2000 CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity. This technical note documents the development of CE-QUAL-W2, Version 3, which incorporates sloping riverine sections. Version 3 has the capability of modeling entire river basins with rivers and interconnected lakes, reservoirs, and/or estuaries. Four example applications illustrate the use of Version 3. Title: CE-QUAL-W2, Version 3 Author: Wells, Scott A., Cole, Thomas M. Year: 2000 CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity. This technical note documents the development of CE-QUAL-W2, Version 3, which incorporates sloping riverine sections. Version 3 has the capability of modeling entire river basins with rivers and interconnected lakes, reservoirs, and/or estuaries. Four example applications illustrate the use of Version 3. Close

• 6. [Article] Validation of the CE-QUAL-W2 Version 3 River Basin Hydrodynamic and Water Quality Model

  CE-QUAL-W2 Version 3, a 2-D (longitudinal-vertical) hydrodynamic and water quality model for river basins combining both river and stratified river-estuary and lakereservoir flow, is a development product ...

  Citation × Citation Citation Abstract Copy Title: Validation of the CE-QUAL-W2 Version 3 River Basin Hydrodynamic and Water Quality Model Author: Wells, Scott A. Year: 2002 CE-QUAL-W2 Version 3, a 2-D (longitudinal-vertical) hydrodynamic and water quality model for river basins combining both river and stratified river-estuary and lakereservoir flow, is a development product of the Waterways Experiment Station in Vicksburg, MS, USA. With the development and release of any revised or reformulated model codes, significant model validation is required. This includes comparison of model results to simple analytical solutions for hydrodynamics and water quality transport, as well as comparison to laboratory and field data. In this paper, the model is compared to numerous analytical solutions for mass transport (1-D advective mass transport) and hydrodynamics (impulsive wind stress on water surface, seiching). Suggestions are presented for proper validation protocols for hydrodynamic and water quality models. Title: Validation of the CE-QUAL-W2 Version 3 River Basin Hydrodynamic and Water Quality Model Author: Wells, Scott A. Year: 2002 CE-QUAL-W2 Version 3, a 2-D (longitudinal-vertical) hydrodynamic and water quality model for river basins combining both river and stratified river-estuary and lakereservoir flow, is a development product of the Waterways Experiment Station in Vicksburg, MS, USA. With the development and release of any revised or reformulated model codes, significant model validation is required. This includes comparison of model results to simple analytical solutions for hydrodynamics and water quality transport, as well as comparison to laboratory and field data. In this paper, the model is compared to numerous analytical solutions for mass transport (1-D advective mass transport) and hydrodynamics (impulsive wind stress on water surface, seiching). Suggestions are presented for proper validation protocols for hydrodynamic and water quality models. Close

• 7. [Article] Automatic Calibration of Water Quality and Hydrodynamic Model (CE-QUAL-W2)

  One of the most important purposes of surface water resource management is to develop predictive models to assist in identifying and evaluating operational and structural measures for improving water quality. ...

  Citation × Citation Citation Abstract Copy Title: Automatic Calibration of Water Quality and Hydrodynamic Model (CE-QUAL-W2) Author: Shojaei, Nasim Year: 2014 One of the most important purposes of surface water resource management is to develop predictive models to assist in identifying and evaluating operational and structural measures for improving water quality. To better understand the effects of external and internal nutrient and organic loading and the effects of reservoir operation, a model is often developed, calibrated, and used for sensitivity and management simulations. The importance of modeling and simulation in the scientific community has drawn interest towards methods for automated calibration. This study addresses using an automatic technique to calibrate the water quality model CE-QUAL-W2 (Cole and Wells, 2013). CE-QUAL-W2 is a two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model for surface water bodies, modeling eutrophication processes such as temperature-nutrient-algae-dissolved oxygen-organic matter and sediment relationships. The numerical method used for calibration in this study is the particle swarm optimization method developed by Kennedy and Eberhart (1995) and inspired by the paradigm of birds flocking. The objective of this calibration procedure is to choose model parameters and coefficients affecting temperature, chlorophyll a, dissolved oxygen, and nutrients (such as NH4, NO3, and PO4). A case study is presented for the Karkheh Reservoir in Iran with a capacity of more than 5 billion cubic meters that is the largest dam in Iran with both agricultural and drinking water usages. This algorithm is shown to perform very well for determining model parameters for the reservoir water quality and hydrodynamic model. Implications of the use of this procedure for other water quality models are also shown. Title: Automatic Calibration of Water Quality and Hydrodynamic Model (CE-QUAL-W2) Author: Shojaei, Nasim Year: 2014 One of the most important purposes of surface water resource management is to develop predictive models to assist in identifying and evaluating operational and structural measures for improving water quality. To better understand the effects of external and internal nutrient and organic loading and the effects of reservoir operation, a model is often developed, calibrated, and used for sensitivity and management simulations. The importance of modeling and simulation in the scientific community has drawn interest towards methods for automated calibration. This study addresses using an automatic technique to calibrate the water quality model CE-QUAL-W2 (Cole and Wells, 2013). CE-QUAL-W2 is a two-dimensional (2D) longitudinal/vertical hydrodynamic and water quality model for surface water bodies, modeling eutrophication processes such as temperature-nutrient-algae-dissolved oxygen-organic matter and sediment relationships. The numerical method used for calibration in this study is the particle swarm optimization method developed by Kennedy and Eberhart (1995) and inspired by the paradigm of birds flocking. The objective of this calibration procedure is to choose model parameters and coefficients affecting temperature, chlorophyll a, dissolved oxygen, and nutrients (such as NH4, NO3, and PO4). A case study is presented for the Karkheh Reservoir in Iran with a capacity of more than 5 billion cubic meters that is the largest dam in Iran with both agricultural and drinking water usages. This algorithm is shown to perform very well for determining model parameters for the reservoir water quality and hydrodynamic model. Implications of the use of this procedure for other water quality models are also shown. Close

• 8. [Article] Accommodation Space in a High-Wave-Energy Inner-Shelf During the Holocene Marine Transgression: Correlation of Onshore and Offshore Inner-Shelf Deposits (0–12 ka) in the Columbia River Littoral Cell System, Washington and Oregon, USA

  The Columbia River Littoral Cell (CRLC), a high-wave-energy littoral system, extends 160 km alongshore, generally north of the large Columbia River, and 10–15 km in across-shelf distance from paleo-beach ...

  Citation × Citation Citation Abstract Copy Title: Accommodation Space in a High-Wave-Energy Inner-Shelf During the Holocene Marine Transgression: Correlation of Onshore and Offshore Inner-Shelf Deposits (0–12 ka) in the Columbia River Littoral Cell System, Washington and Oregon, USA Author: Peterson, Curt D., Twichell, Dave C., Roberts, Michael C., Vanderburgh, Sandy, Hostetler, Steven Year: 2016 The Columbia River Littoral Cell (CRLC), a high-wave-energy littoral system, extends 160 km alongshore, generally north of the large Columbia River, and 10–15 km in across-shelf distance from paleo-beach backshores to about 50 m present water depths. Onshore drill holes (19 in number and 5–35 m in subsurface depth) and offshore vibracores (33 in number and 1–5 m in subsurface depth) constrain inner-shelf sand grain sizes (sample means 0.13–0.25 mm) and heavy mineral source indicators (> 90% Holocene Columbia River sand) of the inner-shelf facies (≥ 90% fine sand). Stratigraphic correlation of the transgressive ravinement surface in onshore drill holes and in offshore seismic reflection profiles provide age constraints (0–12 ka) on post-ravinement inner-shelf deposits, using paleo-sea level curves and radiocarbon dates. Post-ravinement deposit thickness (1–50 m) and long-term sedimentation rates (0.4–4.4 m ka− 1) are positively correlated to the cross-shelf gradients (0.36–0.63%) of the transgressive ravinement surface. The total post-ravinement fill volume of fine littoral sand (2.48x1010m3) in the inner-shelf represents about 2.07x106 m3 yr− 1 fine sand accumulation rate during the last 12 ka, or about one third of the estimated middle- to late-Holocene Columbia River bedload or sand discharge (5–6x106 m3 yr− 1) to the littoral zone. The fine sand accumulation in the inner-shelf represents post-ravinement accommodation space resulting from 1) geometry and depth of the transgressive ravinement surface, 2) post-ravinement sea-level rise, and 3) fine sand dispersal in the inner-shelf by combined high-wave-energy and geostrophic flow/down-welling drift currents during major winter storms. Title: Accommodation Space in a High-Wave-Energy Inner-Shelf During the Holocene Marine Transgression: Correlation of Onshore and Offshore Inner-Shelf Deposits (0–12 ka) in the Columbia River Littoral Cell System, Washington and Oregon, USA Author: Peterson, Curt D., Twichell, Dave C., Roberts, Michael C., Vanderburgh, Sandy, Hostetler, Steven Year: 2016 The Columbia River Littoral Cell (CRLC), a high-wave-energy littoral system, extends 160 km alongshore, generally north of the large Columbia River, and 10–15 km in across-shelf distance from paleo-beach backshores to about 50 m present water depths. Onshore drill holes (19 in number and 5–35 m in subsurface depth) and offshore vibracores (33 in number and 1–5 m in subsurface depth) constrain inner-shelf sand grain sizes (sample means 0.13–0.25 mm) and heavy mineral source indicators (> 90% Holocene Columbia River sand) of the inner-shelf facies (≥ 90% fine sand). Stratigraphic correlation of the transgressive ravinement surface in onshore drill holes and in offshore seismic reflection profiles provide age constraints (0–12 ka) on post-ravinement inner-shelf deposits, using paleo-sea level curves and radiocarbon dates. Post-ravinement deposit thickness (1–50 m) and long-term sedimentation rates (0.4–4.4 m ka− 1) are positively correlated to the cross-shelf gradients (0.36–0.63%) of the transgressive ravinement surface. The total post-ravinement fill volume of fine littoral sand (2.48x1010m3) in the inner-shelf represents about 2.07x106 m3 yr− 1 fine sand accumulation rate during the last 12 ka, or about one third of the estimated middle- to late-Holocene Columbia River bedload or sand discharge (5–6x106 m3 yr− 1) to the littoral zone. The fine sand accumulation in the inner-shelf represents post-ravinement accommodation space resulting from 1) geometry and depth of the transgressive ravinement surface, 2) post-ravinement sea-level rise, and 3) fine sand dispersal in the inner-shelf by combined high-wave-energy and geostrophic flow/down-welling drift currents during major winter storms. Close

• 9. [Article] Convergent Surface Water Distributions in U.S. Cities

  Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However,the scope and consequences of surface ...

  Citation × Citation Citation Abstract Copy Title: Convergent Surface Water Distributions in U.S. Cities Author: Steele, Meredith K., Heffernan, James B., Bettez, Neil D., Cavender-Bares, Jeannine, Groffman, Peter M., Grove, J. Morgan, Hall, Sharon J., Hobbie, Sarah E., Larson, Kelli L., Morse, Jennifer L., Neill, Christopher, Nelson, Kristen C., O'Neil-Dunne, Jarlath, Ogden, Laura A., Pataki, Diane E., Polsky, Colin, Chowdhury, Rinku Roy Year: 2014 Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However,the scope and consequences of surface water redistribution at broad spatialscales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and distribution: in other words, cities will gain or lose water such that they become more similar to each other than are their surrounding natural landscapes. Using a database of more than 1 million water bodies and 1 million km of streams, we compared the surface water of 100 US cities with their surrounding undeveloped land. We evaluated differences in areal ( A) and numeric densities ( N) of water bodies (lakes, wetlands, and so on), the morphological characteristics of water bodies (size), and the density ( D) of surface flow channels (that is, streams and rivers). The variance of urban A, N, and D across the 100 MSAs decreased, by 89, 25, and 71%, respectively, compared to undeveloped land. These data show that many cities are surface water poor relative to undeveloped land; however, in drier landscapesurbanization increases the occurrence of surface water. This convergence pattern strengthened with development intensity, such that high intensityurban development had an areal water body density 98% less than undeveloped lands. Urbanization appears to drive the convergence of hydrological features across the US, such that surface water distributions of cities are more similar to each other than to their surrounding landscapes. Title: Convergent Surface Water Distributions in U.S. Cities Author: Steele, Meredith K., Heffernan, James B., Bettez, Neil D., Cavender-Bares, Jeannine, Groffman, Peter M., Grove, J. Morgan, Hall, Sharon J., Hobbie, Sarah E., Larson, Kelli L., Morse, Jennifer L., Neill, Christopher, Nelson, Kristen C., O'Neil-Dunne, Jarlath, Ogden, Laura A., Pataki, Diane E., Polsky, Colin, Chowdhury, Rinku Roy Year: 2014 Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However,the scope and consequences of surface water redistribution at broad spatialscales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and distribution: in other words, cities will gain or lose water such that they become more similar to each other than are their surrounding natural landscapes. Using a database of more than 1 million water bodies and 1 million km of streams, we compared the surface water of 100 US cities with their surrounding undeveloped land. We evaluated differences in areal ( A) and numeric densities ( N) of water bodies (lakes, wetlands, and so on), the morphological characteristics of water bodies (size), and the density ( D) of surface flow channels (that is, streams and rivers). The variance of urban A, N, and D across the 100 MSAs decreased, by 89, 25, and 71%, respectively, compared to undeveloped land. These data show that many cities are surface water poor relative to undeveloped land; however, in drier landscapesurbanization increases the occurrence of surface water. This convergence pattern strengthened with development intensity, such that high intensityurban development had an areal water body density 98% less than undeveloped lands. Urbanization appears to drive the convergence of hydrological features across the US, such that surface water distributions of cities are more similar to each other than to their surrounding landscapes. Close

• 10. [Article] Water track modification of soil ecosystems in the Lake Hoare basin, Taylor Valley, Antarctica

  Water tracks are zones of high soil moisture that route shallow groundwater down-slope, through the active layer and above the ice table. A water track in Taylor Valley, McMurdo Dry Valleys, was analysed ...

  Citation × Citation Citation Abstract Copy Title: Water track modification of soil ecosystems in the Lake Hoare basin, Taylor Valley, Antarctica Author: Levy, Joseph S., Fountain, Andrew G., Gooseff, Michael N., Barrett, John E., Vantreese, Robert, Welch, Kathleen A., Lyons, W. Berry, Nielsen, Uffe N., Wall, Diana H. Year: 2013 Water tracks are zones of high soil moisture that route shallow groundwater down-slope, through the active layer and above the ice table. A water track in Taylor Valley, McMurdo Dry Valleys, was analysed for surface hydrogeological, geochemical, and biological characteristics in order to test the hypothesis that water tracks provide spatial structure to Antarctic soil ecosystems by changing the physical conditions in the soil environment within the water tracks from those outside the water tracks. The presence of the water track significantly affected the distribution of biotic and abiotic ecosystem parameters: increasing soil moisture, soil salinity, and soil organic matter within the water track relative to soils outside the water track, and reducing soil phosphate, soil pH, and the population of nematodes and other invertebrates in water track soils relative to off track soils. These results suggest that water tracks are distinct and extreme ecological zones in Taylor Valley that provide long-range (kilometre to multikilometre) structure to Antarctic hillslope ecosystems through physical control on soil moisture and solute content. Contrary to expectations, these high soil-moisture sites are not hotspots for faunal biological activity because high soil salinity makes them suitable habitats for only the most halo-tolerant organisms Title: Water track modification of soil ecosystems in the Lake Hoare basin, Taylor Valley, Antarctica Author: Levy, Joseph S., Fountain, Andrew G., Gooseff, Michael N., Barrett, John E., Vantreese, Robert, Welch, Kathleen A., Lyons, W. Berry, Nielsen, Uffe N., Wall, Diana H. Year: 2013 Water tracks are zones of high soil moisture that route shallow groundwater down-slope, through the active layer and above the ice table. A water track in Taylor Valley, McMurdo Dry Valleys, was analysed for surface hydrogeological, geochemical, and biological characteristics in order to test the hypothesis that water tracks provide spatial structure to Antarctic soil ecosystems by changing the physical conditions in the soil environment within the water tracks from those outside the water tracks. The presence of the water track significantly affected the distribution of biotic and abiotic ecosystem parameters: increasing soil moisture, soil salinity, and soil organic matter within the water track relative to soils outside the water track, and reducing soil phosphate, soil pH, and the population of nematodes and other invertebrates in water track soils relative to off track soils. These results suggest that water tracks are distinct and extreme ecological zones in Taylor Valley that provide long-range (kilometre to multikilometre) structure to Antarctic hillslope ecosystems through physical control on soil moisture and solute content. Contrary to expectations, these high soil-moisture sites are not hotspots for faunal biological activity because high soil salinity makes them suitable habitats for only the most halo-tolerant organisms Close