David F Hill

• PhD
• Professor at Oregon State University

This work introduces a novel snow metric, snow water storage (SwS), defined as the integrated area under the snow water equivalent (SWE) curve (units: length-time, e.g., m d). Unlike other widely used snow metrics that capture snow variables at a single point in time (e.g., maximum SWE) or describe temporal snow characteristics (e.g., length of sno...

This work defines a new snow metric, snow water storage (SwS), which is the integrated area under the snow water equivalent (SWE) curve. Other widely-used snow metrics capture snow variables at a single point in time (e.g. maximum SWE) or describe temporal snow qualities (e.g. length of snow season), SwS can be applied at numerous spatial and tempo...

In late spring of 1992, Christopher McCandless crossed the Teklanika River, west of Healy, Alaska (United States). His summer has been well documented both in the book and the movie ‘Into the Wild.’ In early summer of 1992, he attempted to cross back over the river, but was stopped by high waters and he died later that summer. This paper investigat...

Feedback between flow transformation by submerged aquatic vegetation (SAV) and bed morphodynamics influences the long-term survivability of SAV habitats and the engineering services that SAV provides. We conducted a full-scale wave flume experiment to investigate the mechanisms through which finite patches of mimic SAV produce shoreward depositiona...

Bottom friction is an important process in coastal and estuarine environments because it can reduce wave heights and moderate tidal currents. When modeling large systems with spatially varying hydraulic properties, bottom friction values are commonly derived from land use classification products. However, estimation of bottom friction for vegetated...

A physically based snowpack evolution and redistribution model was used to test the effectiveness of assimilating crowd-sourced snow depth measurements collected by citizen scientists. The Community Snow Observations (CSO; https://communitysnowobs.org/, last access: 11 August 2021) project gathers, stores, and distributes measurements of snow depth...

In this study, we examine the effectiveness of incorporating citizen science snow depth measurements into the seasonal snow model chain through data assimilation. We also introduce the Community Snow Observations dataset, a citizen science based snow depth measuring campaign. Improvements to model performance are characterized and evaluated using r...

We demonstrate a linking of moderately high resolution (1 km) terrestrial hydrological models to a 3‐D ocean circulation model having similar resolution in the northern Gulf of Alaska, where a distributed line source of freshwater runoff exerts strong influence over the shelf's hydrographic structure and flow dynamics. The model interfacing is acco...

The coastal ecosystem of the Gulf of Alaska (GOA) is especially vulnerable to the effects of ocean acidification and climate change. Detection of these long-term trends requires a good understanding of the system’s natural state. The GOA is a highly dynamic system that exhibits large inorganic carbon variability on subseasonal to interannual timesc...

Scientists and engineers have observed for some time that tidal amplitudes at many locations are shifting considerably due to nonastronomical factors. Here we review comprehensively these important changes in tidal properties, many of which remain poorly understood. Over long geological time scales, tectonic processes drive variations in basin size...

Abstract. The coastal ecosystem of the Gulf of Alaska (GOA) is especially vulnerable to the effects of ocean acidification and climate change that can only be understood within the context of the natural variability of physical and chemical conditions. Controlled by its complex bathymetry, iron enriched freshwater discharge, and wind and solar radi...

Climate change impacts on extreme water levels (WLs) at two United States Pacific Northwest estuaries are investigated using a multicomponent process-based modeling framework. The integrated impact of climate change on estuarine forcing is considered using a series of sub-models that track changes to oceanic, atmospheric, and hydrologic controls on...

Extreme water levels generating flooding in estuarine and coastal environments are often driven by compound events, where many individual processes such as waves, storm surge, streamflow, and tides coincide. Despite this, extreme water levels are typically modeled in isolated open-coast or estuarine environments, potentially mischaracterizing the t...

We present a simple method that allows snow depth measurements to be converted to snow water equivalent (SWE) estimates. These estimates are useful to individuals interested in water resources, ecological function, and avalanche forecasting. They can also be assimilated into models to help improve predictions of total water volumes over large regio...

A high spatial resolution (250 m), distributed snow evolution and ablation model, SnowModel, is used to estimate current and future scenario freshwater runoff into Glacier Bay, Alaska, a fjord estuary that makes up part of Glacier Bay National Park and Preserve. The watersheds of Glacier Bay contain significant glacier cover (tidewater and land-ter...

A high spatial resolution (250 m), distributed snow evolution and ablation model, SnowModel, is used to estimate current and future freshwater runoff into Glacier Bay, Alaska; a fjord estuary that makes up part of Glacier Bay National Park and Preserve (GBNPP). The watershed of Glacier Bay contains significant glacier cover (tidewater and land-term...

We present a simple method that allows snow depth measurements to be converted to snow water equivalent (SWE) estimates. These estimates are useful to individuals interested in water resources, ecological function, and avalanche forecasting. They can also be assimilated into models to help improve predictions of total water volumes over large regio...

Extreme water levels driving flooding in estuarine and coastal environments are often compound events, generated by many individual processes like waves, storm surge, streamflow, and tides. Despite this, extreme water levels are typically modeled in isolated open coast or estuarine environments, potentially mischaracterizing the true risk to floodi...

Climate change impacts to extreme water levels (WLs) at two United States Pacific Northwest estuaries are investigated using a multi-component process-based modeling framework. The integrated impact of climate change on estuarine forcing is considered using a series of sub-models that track changes to oceanic, atmospheric, and hydrologic controls o...

Combined tidal and wave events are simulated over an idealized marsh environment to quantifiably characterize the cross-shore attenuation of wave height as a function of bottom roughness and submergence depth. Dissipation calculated by the numerical model is compared with existing analytically derived parametric wave height decay models. We propose...

A new project harnesses the power of the winter backcountry recreation community to gather data that are vital to understanding snow, from winter hazards to water resources.

Approximately 14% of the world's population-1.1 billion people-live without access to electricity, and countless more lack access to reliable electricity. This article looks at electrification opportunities via small hydropower strategically placed within rural communities. We approach the challenge through a unique blend of technical feasibility a...

This is an errata for our 2007 paper. The Journal could not find a reviewer so I have put it up here for future researcher to use it and it also gives ideas for future work.

High-resolution regional-scale hydrologic models were used to quantify the response of late 21st century runoff from the Gulf of Alaska (GOA) watershed to changes in regional climate and glacier extent. NCEP Climate Forecast System Reanalysis data were combined with five Coupled Model Intercomparison Project Phase 5 General Circulation Models (GCM)...

While global climate models (GCMs) are useful for simulating climatic responses to perturbations in the Earth's climate system, there are many instances where higher spatial resolution information is necessary. In all instances, interpretation of interpolated or downscaled GCMs must be done cautiously because each method has its own set of assumpti...

Sea-level rise is a global problem, yet to forecast future changes, we must understand how and why relative sea level (RSL) varied in the past, on local to global scales. In East and Southeast Asia, details of Holocene RSL are poorly understood. Here we present two independent high-resolution RSL proxy records from Belitung Island on the Sunda Shel...

Supplementary Figures, Supplementary Tables, Supplementary Note and Supplementary References

Models that seek to predict environmental variables invariably demonstrate bias when compared to observations. Bias correction (BC) techniques are common in the climate and hydrological modeling communities, but have seen fewer applications to the field of wave modeling. In particular there has been no investigation as to which BC methodology perfo...

In support of efforts to reconstruct relative sea level (RSL), we investigated the utility of foraminifera, diatoms and bulk-sediment geochemistry (δ13C, C:N and parameters measured by Rock-Eval pyrolysis) as sea-level indicators in Eurasian sub-Arctic salt marshes. At three salt marshes (<15 km apart) in Dvina Bay (White Sea, Russia), we collected...

We present a Holocene relative sea-level (RSL) database for the Caribbean region (5°N to 25°N and 55°W to 90°W) that consists of 499 sea-level index points and 238 limiting dates. The database was compiled from multiple sea-level indicators (mangrove peat, microbial mats, beach rock and acroporid and massive corals). We subdivided the database into...

Tidal range is one factor in determining the vertical location of local mean sea level, and it is also a contributor to total water levels and coastal flooding. It is therefore important to understand both the spatial distribution of tidal range and the temporal variation in tidal range, over a wide range of scales. Knowledge of historic tidal rang...

Small-scale hydropower systems are popular both in the United States and much of the developing world due to the emphasis on renewable energy and the general cost-competitiveness of hydroelectric power generation. We present a novel modeling package, referred to as the Hydropower Potential Assessment Tool (HPAT), to assess historic and projected fu...

Making meaningful projections of the impacts that possible future climates would have on water resources in mountain regions requires understanding how cryosphere hydrology model performance changes under altered climate conditions and when the model is applied to ungaged catchments. Further, if we are to develop better models, we must understand w...

Analysis of Gravity Recovery Data to determine the trends of terrestrial water mass in Indus Watershed over 10 years of time

A comprehensive study of the Gulf of Alaska (GOA) drainage basin was carried out to improve understanding of the coastal freshwater discharge (FWD) and glacier volume loss (GVL). Hydrologic processes during the period 1980-2014 were modeled using a suite of physically based, spatially distributed weather, energy-balance snow/ice melt, soil water ba...

Robustly understanding connections between the climate, cryosphere, and streamflow is necessary to make informed decisions regarding water resources in mountainous regions. Conceptual models, for instance variations on simple degree-index (SDI) or enhanced temperature index (ETI) formulations of cryosphere heat transfer and melt, are often applied...

The December 2007 storm, otherwise known as the Great Coastal Gale of 2007, was a series of extratropical cyclones that brought highly unprecedented wind speeds and precipitation to the Oregon and Washington coasts of the United States. A storm hindcast using the coupled Advanced Circulation (ADCIRC) and Simulating Waves Nearshore (SWAN) models was...

Numerical tidal models are used to gain information about tides in the present, past, and future. However, modeling strategies are highly dependent on the spatial extent and type of information sought. Physical and numerical issues related to both global and regional tidal modeling are reviewed, including fundamental dynamics, forcing and damping,...

This chapter presents a protocol for synthesizing sea-level data by means of a comprehensive database. A rigorous, objective error assessment assures that all conceivable sources of uncertainty are accounted for, thereby allowing direct comparison of data from different regions and environments. New developments in the methodology presented here in...

A study of the freshwater discharge into the Gulf of Alaska (GOA) has been carried out. Using available streamgage data, regression equations were developed for monthly flows. These equations express discharge as a function of basin physical characteristics such as area, mean elevation, and land cover, and of basin meteorological characteristics su...

Total water levels (TWLs) within estuaries are influenced by tides, wind, offshore waves and streamflow, all of which are uniquely affected by climate change. The magnitude of TWL associated with various return periods is relevant to understanding how the hydrodynamics of a bay or estuary may evolve under distinct climate scenarios. A methodology f...

Monthly total precipitation and mean temperature climate surfaces, gridded to 30-arcseconds (≈1 km at the equator) and available for all global land areas, are presented. These datasets are generated with a Delta downscaling method, using the 30-arcsecond WorldClim climatologies to scale monthly anomaly grids. For monthly mean temperature, the anom...

To better understand the effects of river flow and tidal stage on the propagation of realistic tsunami waves up large rivers, simulations of the Columbia River (United States) were carried out. The two-dimensional depth-averaged version of the advanced circulation model was used. The model was forced with open boundary tides, tidal potential, and r...

A simple theoretical model is presented in order to predict the recirculation velocity in river embayments, also commonly referred to as eddies, gyres, cavities, and dead zones. This velocity is important as it sets the fundamental timescale of the motion in these ecologically important regions. Using only an equilibrium torque balance, basic geome...

We present a high-resolution Gravity Recovery and Climate Experiment (GRACE) mascon solution for Gulf of Alaska (GOA) glaciers and compare this with in situ glaciological, climate and other remote-sensing observations. Our GRACE solution yields a GOA glacier mass balance of –65 AE AE 11 Gt a –1 for the period December 2003 to December 2010, with su...

Areas with high species richness have become focal points in the establishment of marine protected areas, but an understanding of the factors that support this diversity is still incomplete. In coastal areas, tidal currents—modulated by bathymetry and manifested in variable speeds—are a dominant physical feature of the environment. However, difficu...

We investigated the effect of tidal‐range change and sediment compaction on reconstructions of Holocene relative sea level (RSL) in New Jersey, USA. We updated a published sea‐level database to generate 50 sea‐level index points and ten limiting dates that define continuously rising RSL in New Jersey during the Holocene. There is scatter among the...

Tides in the Delaware Bay (USA) have been modeled from 7000 years before present (7 ka) to the present day and for selected future sea-level rise scenarios (100 years, 300 years). Historic bathymetries were constructed through use of glacial isostatic adjustment models and a very high spatial resolution (< 100 m) was used at the shoreline. Future b...

A hydrologic model for basins draining through Pakistan is developed with the specific intent of identifying microhydro sites and assessing their quality. The model outputs runoff which is used to estimate flow rate through each geographic cell. These flow rates are scaled by topographic slope using a relationship for potential power to approximate...

Alaska is vast geographically, is located at high latitudes, is surrounded on three sides by oceans and has complex topography, encompassing several climate regions. While climate zones exist, there has not been an objective analysis to identify regions of homogeneous climate. In this study we use cluster analysis on a robust set of weather observa...

Tidal constituents and datums are computed on a high resolution grid of the northwestern Atlantic Ocean, including the Gulf of Mexico and the Caribbean Sea. A global model is used to determine tidal parameters on a grid with a nominal resolution of 800 × 800. The global model includes self-attraction and loading, drag in shallow marginal seas, and...

Mass variations of glaciers in Alaska/northwestern Canada must be quantified in order to assess impacts on ecosystems, human infrastructure, and global sea level. Here we combine Gravity Recovery and Climate Experiment (GRACE) observations with a wide range of satellite and field data to investigate drivers of these recent changes, with a focus on...

The interpretation of present-day sea-level change, as well as the prediction of future relative sea-level (RSL) rise and its spatial variability, depend increasingly on the ability of glacial isostatic adjustment (GIA) models to reveal non-eustatic components of RSL change. GIA results from the redistribution of mass due to the growth and decay of...

This paper develops an analytical two-part covariance kernel from velocity correlations across a two-dimensional (vertical and flow directions) Particle Image Velocimetry (PIV) flow field. This will form the basis of a model of wave action in flood water that includes the underlying turbulence velocity field using Karhunen–Loéve (KL) expansion. The...

The physical and structural characteristics of instream wood were examined within five streams that represented 200years of stream development following glacial recession within Glacier Bay National Park, Alaska. Wood characteristics altered with watershed age as terrestrial succession progressed and wood was recruited into the riverine environment...

The measurement of water wave characteristics, such as wavelength and wave height, in the surf zone is important for monitoring, prediction of erosion, and numerical model calibration. Traditional methods of measuring wave heights have either been limited to a small number of points or have required contact with the water. An experimental study of...

In order to design marine protected areas that are ecologically meaningful, it would be useful to improve our understanding of headland wake foraging systems, which are commonly exploited by baleen whales and other mobile marine predators. We used humpback whale Megaptera novaeangliae sighting data from 1997 to 2008 in combination with tidal predic...

Changes in species assemblages of intertidal foraminifera can be used to estimate the amount of earthquake-related subsidence during plate-boundary earthquakes at the Cascadia subduction zone. The accuracy and precision of foraminiferal methods in paleoenvironmental reconstruction is underpinned by the relations between contemporary taxa and their...

The natural accumulation of logs, branches and other woody vegetation into the stream environment (coarse woody debris (CWD) accumulations) from adjacent stream banks plays an important role in altering the physical and ecological behaviour of rivers. CWD is often used as a tool in restoration projects to create or enhance instream habitat for biot...

This article describes a video uploaded to the APS DFD Annual Meeting 2009 Gallery of Fluid Motion. The video contains both animations and still images from a three-dimensional volumetric velocimetry measurement set acquired in the flow around a Rushton turbine. Comment: Description of a fluid dynamics video uploaded for the APS DFD Annual Meeting...

Traditional methods of measuring the profile of a scour hole or bed form have poor temporal resolution and may require the temporary cessation of the flow in order to be executed. These are undesirable characteristics since many hydraulic flows have unsteady water-sediment interfaces that can display considerable differences between their "dynamic"...

A simple procedure for predicting the time evolution and equilibrium size of the two dimensional bedform created by a turbulent wall jet is presented. The model applies to a planar jet discharging flush with and parallel to an initially horizontal bed of cohesionless sediment. Additionally, the water is assumed to be deep relative to the initial je...

a b s t r a c t Freshwater discharge is one of the most critical parameters driving water properties within fjord estu-arine environments. To date, however, little attention has been paid to the issue of freshwater runoff into Glacier Bay, a recently deglaciated fjord in southeastern Alaska. Estimates of discharge into Glacier Bay and the outlying...

Volumetric three-component velocimetry measurements have been taken of the flow field near a Rushton turbine in a stirred tank reactor. This particular flow field is highly unsteady and three-dimensional, and is characterized by a strong radial jet, large tank-scale ring vortices, and small-scale blade tip vortices. The experimental technique uses...

This paper summarizes a field campaign designed to investigate the application of stereo photogrammetry to measure water surface elevations. The goal of the field test was to show that, using this technique, wave transformations in near shore waters can be measured with high spatial and temporal resolutions in a large spatial domain (O(10⁴ m²)). Th...

Experiments have been performed to assess the efficiency of mechanical mixers in destratifying water bodies. The effects of Reynolds number, physical scale, and Richardson number were all considered. The results demonstrated that the variation of mixing efficiency with Richardson number was well described by two different power-law regimes. At low...

Volumetric 3-component velocimetry (V3V) measurements have been made of the flow field near a Rushton turbine in a stirred tank reactor. This particular flow field is highly unsteady and three-dimensional, and is characterized by a strong radial jet, large tank-scale ring vortices, and small-scale blade tip vortices. V3V uses a single camera head w...

Alaska, U.S.A, is one of the few remaining locations in the world that has fjords that contain temperate idewater glaciers. Studying such estuarine systems provides vital information on how deglaciation affects oceanographic onditions of fjords and surrounding coastal waters. The oceanographic system of Glacier Bay, Alaska, is of particular interes...

There is an urgent need for a re-assessment of the quality of Holocene relative sea-level (RSL) observations from the Atlantic and Gulf coasts of the United States. Holocene RSL data provide an essential benchmark to compare against other records of RSL change in the last 100-150 years. Only high quality sea-level data reveal spatial and temporal v...

Measurements of the mean and turbulent flow fields in undular and hydraulic jumps have been acquired with single-camera particle image velocimetry PIV. Three Froude numbers, ranging from 1.4 to 3.0, were studied, and in each case data were collected at numerous streamwise locations. The data from these streamwise locations were subsequently compile...

Two sets of experiments related to the scour of cohesionless sediment by planar turbulent jets are presented and discussed. The first set of experiments measures the growth of the scour hole and downstream dune as a function of time. Measurements reveal a bedform that is nearly self-similar and whose growth in time is governed by a power-law relati...

The problem of water waves generated in a horizontally oscillating basin is considered, with specific emphasis on the transient evolution of the wave amplitude. A third-order amplitude evolution equation is solved analytically in terms of Jacobian elliptic functions. The solution explicitly determines the maximum amplitude and nonlinear beating per...

We consider scaling of flow within a stirred tank with increasing Reynolds number. Experimental results obtained from two different tanks of diameter 152.5 and 292.1 mm, with a Rushton turbine operating at a wide range of rotational speeds stirring the fluid, are considered. The Reynolds number ranges from 4000 to about 78,000. Phase-locked stereos...

We consider the question of scaling of flow within a stirred tank with increasing Reynolds number. Experimental results obtained from two different tanks of diameter 15.25 and 29.21 cm with a Rushton turbine operating at a wide range of rotational speed is considered for the scaling analysis. The resulting Reynolds number of the flow ranges from 40...

A set of third-order equations describing the interactions between surface waves and interfacial waves is presented. The specific interaction studied is that of exact subharmonic resonance of two interfacial waves by a single surface wave. The coupled amplitude evolution equations are solved analytically in terms of Jacobian elliptic functions. Upo...

A weakly-nonlinear analysis of the transient evolution of two-dimensional, standing waves in a rectangular basin is presented. The waves are resonated by periodic oscillation along an axis aligned with the wavenumber vector. The amplitude of oscillation is assumed to be small with respect to the basin dimensions. The effects of detuning, viscous da...

An experimental and theoretical study of the hydrodynamic impacts of recreational watercraft in shallow water bodies is presented. Of particular interest is the ability of turbulent prop or jet wash to resuspend bottom sediments. Intuition suggests, and the experiments confirm, that this ability is a strong function of boat speed and water depth.Th...

Non-intrusive velocity measurements in turbulent, stratified flows are hampered by index of refraction fluctuations. These fluctuations can reduce the data rate and quality in laser Doppler velocimetry by displacing the beams. In an experiment with particle image velocimetry (PIV), the displacement of light reflected from particles can produce spur...

Field measurements of the near-bed disturbances induced by planing recreational watercraft are presented. A wide variety of boats and operating conditions were considered. Of particular interest was how the velocity and turbidity at the lake / river bed would vary with water depth, boat speed, and boat power. The results indicate that boats travell...

A weakly nonlinear analysis of two-dimensional, standing waves in a rectangular basin of arbitrary depth is presented. The waves are resonated by periodic oscillation along an axis aligned with the wavenumber vector. First, linear analysis is pursued in order to determine the growth rate of the resonated wave as a function of the basin dimensions,...

 An experimental technique for the creation of any statically stable density profile is presented. This technique is essentially a generalized, unsteady version of the “two-tank” method that is well known to the stratified flow community. It involves specifying the desired density profile and then solving an inverse problem in order to determine th...

The Faraday resonance of interfacial waves in a two-layer, weakly-viscous system in a rectangular domain is presented. A perturbation analysis is pursued and, at the second-order, the scaling of the viscosity results in boundary layer corrections at the solid walls and at the interface. Special attention is paid to the damping in the meniscus regio...

The stirred tank reactor is one of the most commonly used devices in industry for achieving mixing and reaction. We consider a combined experimental/computational approach for the simulation of flow inside a stirred tank. Two sets of experiments are performed to measure the velocity field in the neighborhood of the impeller. The first set of PIV me...

Here we report on results obtained from large eddy simulations of flow inside a stirred tank stirred with a six blade Rushton turbine performed using a spectral multi-domain technique. The computations were driven by specifying the impeller-induced flow at the blade tip radius, which was obtained from Stereoscopic PIV measurements made in the immed...