Abstract

Improving Access to High-Elevation Snowpack Data for Regional Water Resource Management

Sarah Rogers — Wed, 02 Apr 2025 14:13:52 +0000

Improving Access to High-Elevation Snowpack Data for Regional Water Resource Management Sarah Rogers Wed, 04/02/2025 - 08:13 Emelina Catterson , Eric Gosnell , Samuel Plunkett , Isabelle Sease

High elevation snowpack plays an important role in providing regional water resource management, however there is no current practice that efficiently summarizes data at high elevation sites. This gap in accessible information highlights the need for efficient data compilation methods and collaboration between researchers and resource managers. There is potential to consolidate high elevation snowpack data so it is better suited for use by Boulder鈥檚 water resource managers. As snow hydrology interns with Niwot Ridge LTER, we collect SWE from snow depth, snow temperature, grain type/size, and snow density. Data is collected on a weekly basis, with the source alternating between a subalpine forest site and an alpine tundra site. SWE varies drastically throughout the Boulder Creek Watershed, and can prove difficult to accurately estimate from data collected at the subalpine SNOTEL sites alone. The high elevation data is especially useful for resource managers obtaining an accurate representation of regional snowpack and water resources.

Our goal with this project is to compile the data we have collected throughout the 2025 season and standardize it in a usable format for resource managers. We intend to create a graphical representation that resembles a similar format to SNOTEL data, which is typically used by water resource managers in the City of Boulder. This will serve as a more accurate representation of snowpack close to our watershed and enable resource managers to see high-elevation snowpack from the alpine site, which they do not currently have easy access to, promoting collaboration between research institutions and water resource managers. There is potential for this data sharing framework to continue being used throughout the future snow seasons.

Emelina Catterson, Eric Gosnell, Samuel Plunkett, Isabelle Sease 路 GEOG 路 BA Students

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A Statistical Forecasting System for the Water Balance of a Large Terminal Lake in the Great Basin

Sarah Rogers — Wed, 02 Apr 2025 14:08:42 +0000

A Statistical Forecasting System for the Water Balance of a Large Terminal Lake in the Great Basin Sarah Rogers Wed, 04/02/2025 - 08:08 Manish Venumuddula

The rising anthropogenic demand for water and increased variability of water levels is a challenge for lakes across North America. Many terminal lakes in the Great Basin struggle in the face of anthropogenic demand and climate change.

Mono Lake is a terminal lake in eastern California that supplies freshwater to a small fraction of Los Angeles residents. Chronic water level decline has been an issue at Mono Lake for the past century due to a combination of long-term diversions and drought. This has caused ecological and hydrologic damage in the basin, and despite previous conservation efforts and legislation, it still jeopardizes the future of Mono Lake. Mono Lake鈥檚 continuing struggle and the subsequent push for new water management legislation underscores the importance of hydrologic modeling of the past, present, and future to understand how water balance components interact and provide more information for policymakers in California.

In this research, we present a two-step statistical approach to tackle the modeling challenges implicit to Mono Lake. More specifically, we use a modeling framework (the Large Lake Statistical Water Balance Model (L2SWBM)) to close the historical water balance, quantify uncertainty, and provide a probabilistic basis for simulating water levels under different climate and water management conditions. Using results from the L2SWBM, we apply a regular vine copula to capture relationships between water balance components and allow for unlimited sampling and range.

The goal of this research is to create a probabilistic forecasting system of the Mono Lake water balance and equip decision makers/community members with an understanding of the impacts of both climate and human activities on Mono Lake. The forecasting system developed in the study area creates a tool to resimulate historical and future water levels under various diversion and climate scenarios. This allows for a deep analysis of the impacts of each climate and diversion scenario on Mono Lake water levels.

Manish Venumuddula 路 NSF NCAR 路 Researcher

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Modeling formative floods in gravel-bedded rivers with bedfast ice

Sarah Rogers — Tue, 01 Apr 2025 19:59:04 +0000

Modeling formative floods in gravel-bedded rivers with bedfast ice Sarah Rogers Tue, 04/01/2025 - 13:59 Josie Arcuri

Gravel-bedded rivers are shaped during floods. Over time, certain floods do the most 鈥済eomorphic work鈥� on river beds and banks by maximizing the product of sediment transport magnitude and frequency. The flood that does the most geomorphic work is known as the 鈥渇ormative flood鈥� - it may not be the peak, but it reoccurs more often. However, it is unclear if this concept applies to freshet-dominated rivers in the Arctic. Gravel-bedded rivers in the Arctic continuous permafrost zone are occupied by river ice for 7-9 months each year. Freshet-dominated rivers in this region, like the Canning River, AK, receive a peak flood following snow melt while river ice can resist breakup for weeks, extending flood duration and magnitude. Still, the spring freshet occurs when hydraulic cross-sections are restricted by bedfast ice, limiting bed and bank exposure, but maximizing stage height. In contrast, summer floods generated by storm runoff occur when ice is absent, multiple times per year. Still, river bank and bed gravel is coarse and difficult to transport under low flows. We aim to investigate which flood maintains the Canning River鈥檚 hydraulic geometry, and more generally the hydraulic geometry of all ice-impacted, gravel-bedded rivers.
We explore if there is a formative flood for rivers that develop bedfast river ice with Basement V4. We focus on a 20 km long reach of the Canning River in Arctic Alaska, where we monitored break-up period from 2021 through 2024. We use USGS data for realistic peak discharges and ArcticDEM for surface topography, and field measurements of river ice thickness as primary model inputs. We assess geomorphic significance with metrics for potential sediment transport. To quantify the geomorphic significance, we compare bed and bank shear stresses produced by floods to thresholds for sediment entrainment and bank widening.
Initial results suggest that no realistic discharge can fill the bankfull channel or erode river banks when the channel is free of ice. Conversely, we find that these floods can sediment transport and bank erosion when bedfast ice persists. For the Canning River, the spring freshet is likely the formative flood. Our findings also show that the bedfast river ice can enhance bank erosion and might lead to wider rivers. The significance of river ice in this setting emphasizes that the stability of Arctic Rivers depends on river ice.

Josie Arcuri 路 GEOL 路 PhD Student

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Effects of Air Temperature Warming on Groundwater Flow in an Alpine, Glacierized Watershed

Sarah Rogers — Tue, 01 Apr 2025 19:54:46 +0000

Effects of Air Temperature Warming on Groundwater Flow in an Alpine, Glacierized Watershed Sarah Rogers Tue, 04/01/2025 - 13:54 Corrine Liu

Glacial mass loss due to climate change has been well documented for decades and is projected to continue as air temperatures rise. Baseflow, known as a proxy for groundwater discharge to streams, can be derived from subglacial melt recharge. The groundwater regime thus acts as a hydrologic buffer and connector between glacial melt recharge and streamflow, particularly during periods of low precipitation or overland flow. Understanding the temporal and spatial relationship between glacial melt, baseflow, and subsequent streamflow is necessary to assess the sustainability of current and future streamflow conditions. To evaluate how groundwater flow connects glacial meltwater to downstream hydrology both temporally and spatially, a 2D coupled heat transfer and groundwater flow model with seasonal freeze-thaw was developed using USGS Saturated-Unsaturated Transport modeling software (SUTRA).
Arikaree glacier is an alpine glacier located in Green Lakes Valley in the upper Boulder Creek watershed in Boulder, 欧美口爆视频. Melting of Arikaree has potentially notable impacts on streamflow. Because of Arikaree鈥檚 small size, changes in mass balance occur on human timescales, which can be feasibly observed and underscore the importance of understanding flow dynamics in this region. Using 3 different air temperature warming scenarios, based on the Intergovernmental Panel on Climate Change (IPCC) projections or observed warming trends within the Green Lakes Valley watershed, the subsurface temperature and groundwater flow field underneath Arikaree glacier is simulated. Groundwater flow and heat transport in alpine regions is defined by phase transitions between solid ice and liquid water as subsurface temperature fluctuates seasonally. With future warming the spatial extent of seasonal freeze-thaw may expand, impacting glacial melt-groundwater-surface water dynamics. We elucidate groundwater discharge rates, and how these rates vary seasonally and throughout decades into the future. Furthermore, we aim to quantify how the addition of a frozen soil routine, in which changes to subsurface permeability due to the presence of ice are considered, impacts the magnitude and location of groundwater discharge under projected air temperature warming scenarios.

Corrine Celupica-Liu 路 GEOL 路 MS

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Using Photogrammetry to Monitor Hydrologic and Geomorphic Changes in West Stroh Gulch

Sarah Rogers — Tue, 01 Apr 2025 19:47:56 +0000

Using Photogrammetry to Monitor Hydrologic and Geomorphic Changes in West Stroh Gulch Sarah Rogers Tue, 04/01/2025 - 13:47 Eric Balderrama Sanchez

Urban development can have a large impact on streams, and tracking these changes over time is important for future urban planning. This project focuses on West Stroh Gulch, a non-perennial stream in Parker, 欧美口爆视频, where new housing development is underway. To monitor how the landscape and stream morphology change, we are using drone-based photogrammetry to create high-resolution Digital Elevation Models (DEMs) and orthomosaic maps. By flying a drone every few months and processing aerial imagery, we can generate a visual timeline of how urbanization affects the stream channel and surrounding area. These models will be compared over time to highlight topographic changes and help improve our understanding of development-driven hydrologic shifts.

Eric Balderrama Sanchez 路 CVEN 路 BS Student

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Laboratory Experiments to Understand Post-Wildfire Soil Sealing Processes in Complex Terrain

Sarah Rogers — Tue, 01 Apr 2025 19:44:10 +0000

Laboratory Experiments to Understand Post-Wildfire Soil Sealing Processes in Complex Terrain Sarah Rogers Tue, 04/01/2025 - 13:44 Nana Afua Gyau Frimpong

The effects of wildfire ash on soil properties, particularly its role in soil sealing, have far-reaching consequences for hydrological processes. The western United States faces an increasing frequency and intensity of 欧美口爆视频, which has implications for post-fire soil behavior. Here, we aim to advance the understanding of soil sealing and hydrological fluxes following 欧美口爆视频, focusing on the impacts of ash on the ground surface after the first rainstorms following a wildfire. Using controlled laboratory experiments, we assessed changes in hydraulic conductivity at the soil-ash interface, utilizing the mini-disk infiltrometer, KSAT, and HYPROP instruments. Soils treated with ash demonstrated an increase in water retention and unsaturated hydraulic conductivity but a decrease in field-saturated hydraulic conductivity. At the soil interface there was an increase in hydraulic conductivity. The (Kfs) for the experiment flumes rose from 48.5 cm/day to 112.97 cm/day post-burn (p-value = 0.00015) and declined from 112.97 cm/day to 51.58 cm/day post-rainfall (p-value = 0.000015). The impact of slope angle on ash erosion was minimal. 欧美口爆视频 80% of the ash applied to the surfaces is retained after rainfall across different slope areas. Ash affects soil hydraulic properties in the short term, but its impacts can vary depending on environmental factors such as rainfall intensity and suction conditions.

Nana Afua Gyau Frimpong 路 University of Wyoming Civil Engineering 路 MS Student

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Comparison of Landscape Types on the Urban Heat Island Effect

Sarah Rogers — Tue, 01 Apr 2025 19:36:24 +0000

Comparison of Landscape Types on the Urban Heat Island Effect Sarah Rogers Tue, 04/01/2025 - 13:36 Nicholas Guthro

The urban heat island effect (UHI) is the studied effect that urbanized areas experience higher temperatures than non-urbanized areas due to the increase in buildings, roads, and other infrastructure. UHI has been seen to affect people living in areas classified as socially vulnerable disproportionately. Newer metrics, like Wet Bulb Globe Temperature (WBGT), are being used instead of air temperature to more accurately capture UHI's effects on individuals as it captures air temperature along with other metrics like humidity, cloud cover, and wind speed. This study looks at initial field data that captured WBGT over five different landscapes over three days in a park in Denver, 欧美口爆视频. Initial results show that turfgrass alternatives such as native grass and squeegee planting beds have similar cooling effects as conventional turfgrass. Upcoming work, such as remote sensing of large-scale replacement projects and further location of fieldwork, will be discussed.

Nick Guthro CVEN PhD Student

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Evapotranspiration and soil water content estimation of four urban landscape vegetations using UAV-based multispectral and thermal imagery

Sarah Rogers — Tue, 01 Apr 2025 18:17:44 +0000

Evapotranspiration and soil water content estimation of four urban landscape vegetations using UAV-based multispectral and thermal imagery Sarah Rogers Tue, 04/01/2025 - 12:17 Zahra Amiri

Accurate assessment of evapotranspiration along with soil water content (SWC) dynamics in a heterogeneous urban landscape is fundamental for developing effective water management practices. The unmanned aerial vehicle (UAV) remote sensing with high spatial and temporal resolution offers a promising method for monitoring SWC and spatial mapping of ET. In this study, UAV-based multispectral and thermal data were acquired in an experimental field with four landscape groundcover species over two years (May-October 2022 and 2023). Two regression models, including multiple linear regression (MLR) and random forest regression (RFR), were used to predict soil moisture at depths of 10 and 30 cm. The results indicated that both regression models, MLR and FRF, exhibited a relatively good SWC prediction accuracy with Pearson鈥檚 r ranging 0.62-0.68, root mean square error (RMSE) ranging 0.034-0.048 cm3cm-3, and mean absolute error (MAE) ranging 0.034-0.038 cm3cm-3. Additionally, two energy balance models, a modified version of SSEBop and pySEBAL, were used to estimate ET for four groundcover species. The performances of models were evaluated against measured ET using the soil water balance approach. Model comparisons indicated that ET estimates for both models correlated well with ET measurements, with Pearson鈥檚 r ranging from 0.798-0.928 for the modified SSEBop and 0.843-0.961 for the pySEBAL model. However, the pySEBAL model had lower RMSE values (0.660-1.155 mm day-1) compared to the SSEBop model (0.870-1.270 mm day-1). This study shows that high-resolution UAV imagery combined with energy balance models can be used to estimate ET accurately for different urban vegetation types.

Zahra Amiri 路 CVEN 路 Postdoctoral Associate

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Geomorphic Response to Low-Head Dam Removal in Steep Mountain Streams

Sarah Rogers — Tue, 01 Apr 2025 18:12:36 +0000

Geomorphic Response to Low-Head Dam Removal in Steep Mountain Streams Sarah Rogers Tue, 04/01/2025 - 12:12 Virgil Alfred

Dams disrupt sediment and hydrologic connectivity, fragmenting river ecosystems and altering geomorphic and ecological processes. In response, dam removals have increased to restore longitudinal stream connectivity and ecosystem function. However, we still lack a comprehensive understanding of the geomorphic responses to dam removal, particularly for low-head dams in high-gradient environments. This study examines the geomorphic and ecological effects following the removal of the Lake George diversion structure, a small diversion dam on the South Fork of the South Platte River, CO, in 2023. During removal, reservoir sediment was removed and the channel was re-shaped. Using a Before-After-Control-Impact design, we are monitoring three control cross-sections far enough upstream of the former dam to be unaffected by the removal, three cross-sections in the former impoundment immediately upstream of the dam, and three cross-sections immediately downstream of the structure location, collecting pre- and post-removal data.

At each cross-section, we are conducting RTK-GPS surveys to assess morphologic change caused by, and in the years following, dam removal. We are also collecting bed and subsurface sediment samples for grain size analysis to evaluate textural changes in response to the removal and restoration work. We are collecting benthic macroinvertebrates to provide insight into the early ecological responses to the removal. Preliminary results indicate that although the dam removal and restoration work dramatically reshaped the channel (width and depth changes of several meters), only minor natural geomorphic change has occurred in the year since removal (maximum width and depth changes of a few decimeters). Ongoing and future work will include developing models to predict geomorphic responses to dam removals and channel restoration in steep mountain streams. This research enhances our understanding of how rivers adjust to human-driven disturbances, both in the short term and over longer timescales, following dam removal and restoration.

Virgil Alfred 路 GEOG 路 MA Student

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Patterns and hydroclimatic controls on stream temperature change in US national parks

Sarah Rogers — Tue, 01 Apr 2025 18:10:51 +0000

Patterns and hydroclimatic controls on stream temperature change in US national parks Sarah Rogers Tue, 04/01/2025 - 12:10 Theo Kuhn

Water temperature is an important physical variable that affects most aquatic ecosystem functions, including biogeochemical reaction rates, phenology, and species fitness. We analyzed >60 water temperature records from US national parks in the Western US and Appalachian Mountains to identify trends in stream temperatures from 2008-2023, characterize the seasonality of stream temperature change, and assess the contribution of several hydroclimatic variables (e.g., air temperature and discharge) to observed stream temperature patterns. A series of site-specific generalized additive models (GAMs) were used for trend analysis and quantifying the effect of covariates. Several case studies in representative and notable records are highlighted. Estimates of historical stream temperature change will provide park researchers and resource managers with physical data to understand observed ecological changes, while identification of important covariates will inform planned projections of stream temperature across the NPS system.

Theo Kuhn 路 GEOG 路 MA Student

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