Lightning Talk

Variability of Residence Time in Arctic Back-Barrier Estuaries

Anonymous — Wed, 12 Apr 2023 04:53:05 +0000

Variability of Residence Time in Arctic Back-Barrier Estuaries Anonymous (not verified) Tue, 04/11/2023 - 22:53 Tina Geller

Along a quarter of the Beaufort Sea coast, back-barrier estuaries modulate the transport and transformation of nitrogen and carbon, impacting food webs and carbon budgets. It is unclear what effect rapid Arctic change will have on coastal biogeochemistry, partly because present-day spatial and temporal variability of residence time in Arctic back-barrier estuaries is unknown, which complicates efforts to predict future change. This study investigates the residence time of water in Arey, Kaktovik, and Jago Lagoons, three back-barrier estuaries along the Beaufort Sea coast of northern Alaska. Estimates of residence time based on the volume of the lagoon and river input suggest that residence time in the model domain range from less than one month to several months, depending on the river discharge. These preliminary results assume the estuary is not frozen and is in steady state. Ongoing work to investigate the spatial and temporal variability in residence time of water in these estuaries includes implementing a hydrodynamic numerical model, the Regional Ocean Modeling System (ROMS). The model accounts for processes including local winds, rivers, and larger scale circulation in 2019, and future work includes accounting for sea ice and waves, as well as validating the model. Analysis will focus on spatial and temporal variations in residence time and other circulation dynamics. Results will inform efforts to predict future coastal Arctic changes to circulation and carbon cycles.

Graduate student Atmospheric and Oceanic Sciences, CU Boulder

Tina Geller

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Using Citizen-Reported Data to Determine Spatiotemporal Trends in Pluvial Flooding in Denver, babyֱ��app

Anonymous — Wed, 12 Apr 2023 04:51:10 +0000

Using Citizen-Reported Data to Determine Spatiotemporal Trends in Pluvial Flooding in Denver, babyֱ��app Anonymous (not verified) Tue, 04/11/2023 - 22:51 Stacie DeSousa

Urban flooding is an increasing threat to city and resident well-being. Flooding in babyֱ��app can be categorized as pluvial or fluvial. Fluvial flooding occurs when stream water overflows the stream bank, whereas pluvial flooding is the result of a precipitation event’s intensity exceeding capacity of the drainage system. The Federal Emergency Management Agency (FEMA) typically reports losses attributed to fluvial flooding, discounting impacts of pluvial flooding. This study will use municipal service requests reporting on street flooding in Denver, babyֱ��app from 2000-2019 in coordination with Mile High Flood District rain gage data to develop a spatiotemporal database of street flooding occurrence. Connecting the rain gage closest to a municipal service request will inform storm characteristics which lead to street flooding. This database can help direct flood mitigation efforts and stormwater management in the city. Additionally, this work can contribute to longer term studies on drivers of urban flooding.

Graduate student CU Boulder

Stacie DeSousa

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The Well Geochemistry Logger (WGL): An open-source platform for continuous, in-situ groundwater chemistry measurement

Anonymous — Wed, 12 Apr 2023 04:39:13 +0000

The Well Geochemistry Logger (WGL): An open-source platform for continuous, in-situ groundwater chemistry measurement Anonymous (not verified) Tue, 04/11/2023 - 22:39 Harry Brodsky , Tristan Caro

High-frequency hydrogeochemical monitoring has revolutionized our understanding of surface water in the past decade by providing a detailed record of hydrologic system response to cyclical forcings (e.g. days, seasons) and instantaneous perturbations (storms, anthropogenic contaminations or mitigations), but the high-frequency dynamics of groundwater chemistry remain enigmatic because of practical and technological hurdles such as high pressure in deep aquifers or the inaccessibility of field sites. Prior attempts to collect high-frequency groundwater chemistry measurements have utilized surface-based sensor suites that rely on pumps for sample delivery to the sensors. However, this continuous pumping approach perturbs groundwater systems in unknown ways, and the machinery can introduce a variety of contaminants including organic lubricants, which frustrate geochemical studies. Furthermore, these invasive and mechanically complex systems have not been proven at depths greater than 100 m and cannot be deployed at inaccessible field sites. The Well Geochemistry Logger (WGL) is a small data-logging sensor suite enclosed in a pressure-rated aluminum capsule. The WGL has two operational modes: depth profiling and continuous measurement at static depth. In its current stage of development, the WGL can measure electrical conductivity, temperature, and depth (CTD) of well fluids as deep as 400 m; future iterations will include pH/ORP sensors. Upon recovery, the WGL can connect to a laptop to transfer data. The WGL was successfully field-tested in January 2023 at the Samail Ophiolite, Oman, where it was used to profile the electrical conductivity of extremely basic well waters to depths exceeding 250 m. The WGL recorded conductivities over 6000 µS/cm and helped identify two distinct fluid layers based on their conductivities. These real-time observations informed sampling strategies and validated other measurements obtained from fluid samples. The WGL is made from affordable, commercially available components and based on Arduino, an open-source electronics framework. We propose the WGL as a solution to challenges that currently impede the study of groundwater chemistry dynamics.

Graduate student Geology, CU Boulder

Harry Brodsky

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Tardigrade Abundance and Grazing Habits in the Freshwater Streams of the Dry Valleys.

Anonymous — Wed, 12 Apr 2023 04:36:27 +0000

Tardigrade Abundance and Grazing Habits in the Freshwater Streams of the Dry Valleys. Anonymous (not verified) Tue, 04/11/2023 - 22:36 Natalie Aranda

The microbial mats in the Antarctic Dry Valley freshwater streams host a myriad of cyanobacteria, algae, and microscopic animals whose ecosystem-level interactions are not fully understood. Previous research investigating this ecosystem’s food web has not considered the role of tardigrades as grazers. In the present study, we sampled four types of microbial mats– red, orange, black and green– across eight separate streams in Taylor Valley. All animals were extracted from each mat and their relative abundance per sample were counted. A single morphospecies of tardigrade was identified and individuals were isolated and externally sterilized to perform a metagenomic analysis of their gut contents. This data is compared to the relative abundances and is used in a discussion to reevaluate the role of tardigrades in stream ecosystems where their influence as top-down controllers has not been previously considered.

Graduate student Civil, Environmental, and Architectural Engineering, CU Boulder

Natalie Aranda

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Non-Perennial Stream Monitoring in a Semi-Arid Rangeland Slated for Development

Anonymous — Wed, 12 Apr 2023 04:33:24 +0000

Non-Perennial Stream Monitoring in a Semi-Arid Rangeland Slated for Development Anonymous (not verified) Tue, 04/11/2023 - 22:33 Dixie Poteet

Despite the recognizable impacts urbanization has on stream morphology and flow patterns, there are many challenges when it comes to accurately predicting and quantifying these impacts. This is especially true for non-perennial streams in semi-arid rangelands. Non-perennial streams tend to lack complete records for streamflow presence and absence. Quantifying how stream channels change in developing landscapes can be problematic without a historical pre-development baseline to compare to. This project focuses on a non-perennial stream channel in West Stroh Gulch, located in Parker, babyֱ��app, an area south of Denver, U.S.A. West Stroh Gulch is a semi-arid rangeland slated to undergo housing development within the next few years. Stream presence and absence is recorded at multiple locations along the stream network with time-lapse photography. Recorded precipitation events and corresponding photos are reviewed to quantify what storm intensities and cumulative depths do, or do not, trigger a flow response. Additional visual observations including soil moisture, standing water, and snow cover are recorded. After more than two years of field camera monitoring, one precipitation event with a total depth of 92-mm and maximum 60-minute intensity of 50-mm per hour triggered streamflow in the channel. In comparison, there were 79 other rain events with depths ranging from 1-mm to 44-mm and intensities from 1-mm per hour to 34-mm per hour that did not lead to flow. Time-lapse observations will continue through the stages of development to capture future stream channel responses to precipitation events and a changing landscape. In addition to continuing time-lapse photography observations, a hydraulic model of the watershed will be built. Topographic pre-development data collected with drone flyovers is used to construct a DEM (Digital Elevation Model) surface of the watershed. This pre-development DEM surface will be combined with SWMM generated post-development flows in the hydraulic model to predict post-development changes to the channel morphology. Model predictions can be compared with actual channel changes over time. Combining model predictions with ongoing observations will create a valuable case study of predicting pre to post development changes in a semi-arid rangeland’s non-perennial stream.

Graduate student Civil Engineering, babyֱ��app State University

Dixie Poteet

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Niwot Ridge Snow Hydrology Intern Research

Anonymous — Wed, 12 Apr 2023 04:23:35 +0000

Niwot Ridge Snow Hydrology Intern Research Anonymous (not verified) Tue, 04/11/2023 - 22:23 Leo Zook , Nastia Werner , RJ MEthven , Alexandre Collin , Julia Johansson , Ryan Hondorp

Snow Hydrology Research at the Mountain Research Station on Niwot Ridge

This internship consists of a group of 6 undergraduate students, the guidance of 2 graduate students, 2 CU professors, Dr. Noah Molotch and Dr. Keith Musslemen, and MRS scientist Jen Morse. The group goes on weekly trips to the Mountain Research Station on Niwot Ridge to collect data at two sites, but, due to poor weather this year, we have spent the majority of our time at a lower altitude site called C1. There have been few opportunities to go up to the Tundra site on top of Niwot Ridge. There have been decades of data taken at these locations, so while in-person data collection is difficult and can have inaccuracies, the long-lasting history of the data continues to be relevant and important. Our group hikes from the MRS up to the C1 site, we then dig down through the snow to the soil, making sure the pit is large enough to fit a person and allow them to collect data without disturbing the area of interest. The first few field days, we dug snowpits to fit one person, then we decided to create larger pits so multiple measurements could be taken at once. Using our shovels to shave off any unwanted protruding snow, we create a flat surface inside the pit to collect our data. This includes snow density, temperature, snowpack structure, grain size, grain shape, snow water equivalent, and more. While collecting our data, we cautiously make sure our instruments are performing at their best, avoid picking up impurities like soil and vegetation, create efficient working conditions, and diligently record our data. To collect the aforementioned data, our group utilizes a variety of equipment. For example, hand lenses are used to view snow crystals and better understand the snowpack structure, and density sampling equipment is used to calculate the snow water equivalent and density of individual snowpack segments. These measurements can then be compared to decades of previous historical data to make inferences and understand changes that are occurring at and around Niwot Ridge. This information impacts our understanding of babyֱ��app’s historical snowpack changes, especially on the front range. Overall, the internship acts as a great tool to introduce field snow hydrology research to new students and maintain historical and scientific databases.

Undergraduate students Geography, CU Boulder

Leo Zook, Julia Johansson and Ryan Hondorp

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Investigation of Barium as a Temperature Proxy in Corals

Anonymous — Wed, 12 Apr 2023 04:20:24 +0000

Investigation of Barium as a Temperature Proxy in Corals Anonymous (not verified) Tue, 04/11/2023 - 22:20 Christina Rorres

Trace element concentrations in the aragonite skeletons of massive coral colonies can be measured to reconstruct seasonal- to centennial-scale variability in sea surface temperature (SST). Coral strontium-calcium (Sr/Ca) ratios are commonly used as a proxy for SST. However, barium-calcium (Ba/Ca) ratios, while especially sensitive to temperature in laboratory precipitation experiments, have not been explored as a coral SST proxy because seasonal Ba input from rivers overwhelms the SST signal in the coral skeleton. In this study, we investigated the Ba/Ca-SST relationship in corals from the Red Sea (Figure 1) where Ba from river runoff is absent. Ba/Ca and Sr/Ca were measured in three Porites lutea coral cores, showing distinct seasonal cycles primarily influenced by SST, with infrequent spikes in Ba/Ca due to Ba deposition during dust storms (Figure 2). After removing the Ba/Ca peaks from dust storms, the resulting Ba/Ca time series show strong and significant correlations to SST, similar to Sr/Ca (Figure 3). Comparing Ba/Ca directly to Sr/Ca for each coral results in strong correlations that agree closely with experimental data. Our findings reveal the quantitative Ba/Ca-SST relationships in corals, and suggest that coral Ba/Ca can be used as a reliable temperature proxy in areas without river runoff.

Undergraduate student, Geography and Communications with a minor in Art University of Denver

Christina Rorres

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Incorporating Programming Into an Undergraduate Hydrology Course: Lessons Learned

Anonymous — Wed, 12 Apr 2023 04:16:42 +0000

Incorporating Programming Into an Undergraduate Hydrology Course: Lessons Learned Anonymous (not verified) Tue, 04/11/2023 - 22:16 Jacob Kravits

The importance of programming is ever-increasing for modern hydrologists and water resources analysts. As the complexity of water problems rapidly grows, so too does the complexity of required solutions. As industry and academic workflows become increasingly automated, coupled, and rapidly developed, software with advanced graphical user interfaces may not be feasible. This talk presents a short synopsis of efforts to prepare undergraduate hydrology students for such cases – focusing on how programming and related concepts were incorporated into an undergraduate hydrology course. Specifically, this talk presents examples of hydrologic concepts that were effectively taught using programming. This presentation also includes some practical recommendations on software platforms for reducing the friction of incorporating programming into undergraduate classes.

Graduate student Civil Engineering, CU Boulder

Jacob Kravits

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Grain Size Distribution Analysis of Coastal Deltaic Sediments in Wake of Hurricane Ida

Anonymous — Wed, 12 Apr 2023 04:09:46 +0000

Grain Size Distribution Analysis of Coastal Deltaic Sediments in Wake of Hurricane Ida Anonymous (not verified) Tue, 04/11/2023 - 22:09 Joshua Ferry

As climate change continues to alter weather patterns and amplify the intensity of extreme storm events, the unique and wide-ranging effects on coastal deltaic ecosystems must not be overlooked. This study explores the effects of Hurricane Ida, a category four cyclone that made landfall at Port Fourchon on August 26th, 2021, and its effects on sediment distribution and nutrient cycling in Mississippi Delta topset sediment. Nearshore multi-core sediment samples (0 to 65 centimeters depth) from the top of the seabed were collected at several offshore locations from the proximal coast zone 11 days before the hurricane impacted the region. The locations were again sampled in December 2021, March 2022, June 2022, and August 2022, providing an invaluable opportunity to study the disturbance and recovery of the seabed and its impacts on the local biogeochemical cycles. This study focused on grain size analysis, where distributions of particle sizes could be compared across locations and dates. Change in sediment composition in the year following the hurricane can be used to gain insight on the disturbance to nutrient cycling as a result of Hurricane Ida. Significant recycling of organic and inorganic nutrients occurs between the seabed and the water column, becoming available for use by diatoms and detritivores that help regulate nutrient cycles. Sediment distributions of 170 samples were analyzed using a Mastersizer-3000, a device capable of measuring particles as small as ten nanometers in diameter. Sediment was broken down into individual particles and suspended, after organic material and plastics were carefully removed. Smaller particles including clay and fine silt decreased all the cores following Hurricane Ida, while larger particles such as sand appeared to be more varied at different depths in the seabed. A small increase in finer particle buildup in March and June at one particular location suggested steady deposition following the storm. Between June and August of 2022, there was a spike in smaller particles whereas the sand distribution matched the pre-hurricane distribution more closely. A possible explanation is rapid sediment deposition from the Mississippi River. With the fishing industry in this region generating over half a trillion dollars annually, it is increasingly important for high resolution sampling campaigns to be conducted, as the impacts of climate change continue to develop.

Undergraduate student Geosciences, CU Boulder

Joshua Ferry

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Examining Outdoor Residential Water Use in the Urban Areas of the babyֱ��app River Basin

Anonymous — Wed, 12 Apr 2023 04:06:06 +0000

Examining Outdoor Residential Water Use in the Urban Areas of the babyֱ��app River Basin Anonymous (not verified) Tue, 04/11/2023 - 22:06 Nicholas Guthro

The babyֱ��app River Basin services the residential water use needs of nearly 40 million people. Residential use is the largest component of water use in urban areas, with outdoor water use representing a significant portion of a household’s water budget. The outdoor portion of residential use is often not reported due to most residences tracking all usage combined. This lack of data can be challenging when trying to regulate or pass policy that attempts to reduce outdoor usage. In this study the water use data of twenty-two urban areas in the babyֱ��app River Basin Service area between 2005 and 2017 was retrieved from Hydroshare. These data were used to create Python functions that can estimate the per capita monthly outdoor water usage and display monthly and yearly water usage data. The outdoor water usage was calculated by finding the month of each year with the lowest water usage and then subtracting that value from the rest of the months in that water year. This estimation was done by assuming that the lowest monthly value is the average monthly indoor usage as it is used across each season. Results show a large variability in outdoor water usage between different population sizes and city locations. Cities that started implementing watering restrictions before 2017, such as Las Vegas, saw a steady decrease in water usage over the study period. Our future work will include examining a longer time frame of data from more cities in the river basin and seeing how various explanatory variables (population, region, climate, and policy) can help predict the outdoor water use in a city. This work can help quantify the amount of outdoor water usage for municipalities within the babyֱ��app River Basin usage area and allow for urban areas to see the effects of water use reduction efforts.

Graduate student Civil Engineering, CU Boulder

Nicholas Guthro

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