Poster Sessions at the 2023 Symposium
Posters will be displayed in Fremont. Information about poster setup, take-down, and judging »
An overview of groundwater well siting using geophysical methods
Austin Bergerson, hydroGEOPHYSICS Inc
Discovering new groundwater sources is integral to mines. However, many traditional methods for subsurface investigation require invasive techniques, such as drilling to obtain data at point locations to infer what is happening on a broader scale. Geophysical methods — in this case, electrical resistivity — can provide a rapid, nonintrusive view of the subsurface up to the regional scale. This case study details a recent electrical resistivity survey that we conducted to characterize potential well locations for a mine site in Arizona. A model highlighted a number of fault and fracture zones, which are good potential well sites since they tend to increase the porosity and transmissivity. It was unclear which fault zones would produce good yields, a condition that depends on the occurrence of clay-rich fault gouge that can reduce the porosity and transmissivity of these structures. The resistivity results were able to identify potentially productive fault zones. The use of the high-resolution, spatially continuous geophysical information, paired with tectonic and hydrology information, can help site productive wells.
Identifying critical headwaters in the San Juan River basin: Characteristics and strategies for downstream water security in the arid southwestern U.S.
Eric Sjöstedt, NAU
Mountainous headwaters have been shown to disproportionately generate runoff flows compared to their downstream areas. Major Western metropolitan areas such as Phoenix, Tucson, Denver, Salt Lake City, Las Vegas, Los Angeles, and San Diego depend on the mountainous Colorado River basin for all or some of their water. Prior studies identifying critical runoff generation areas have lacked the fine-scale spatial resolution for adequate systems-level decision-making. As a significant tributary of the Colorado River, the San Juan River basin (SJRB) is an essential water source for the arid southwestern U.S., particularly for Arizona. The goal of this study was to identify the critical runoff generation areas in the SJRB using the relative water yield (RWY) equation developed by Viviroli et al. (2007) and subsequent adaptations. We used high-resolution runoff, land cover, and topographic data to investigate the contributions of each component. We also examined changes in the variability of runoff generation and land cover composition over time to identify controls..
Tailoring hydrologic modeling for improved water resources decision support: A mixed ensemble approach
Abigail Kahler, UA
One of the challenges of hydrologic modeling is quantifying uncertainty; initially small uncertainties magnify over time, increasing the costs of miscalculated decisions. Hydrologic models help predict consequences but are limited by sparse data and uncertainty. This suggests a need for multiple models, and it is worthwhile to pay special attention to less probable, still plausible models that predict consequential outcomes. We call these models of concern (MOCs). We propose a method of combining two ensembles: one comprising the best-fitting calibrated models, and another entirely of MOCs. The usefulness of each model’s prediction to the stakeholder is defined through a utility function: utility may be low or high, depending on the associated consequences, and its threshold can be set based on risk tolerance. The mixed ensemble involves an iterative process that allows the stakeholder to reconsider their willingness to accept risk according to the likelihood of a consequential outcome. This process represents stakeholder concerns more fully than a single ensemble, which only considers goodness-of-fit.
The Arizona Streamgage Catalog (AZStreamCAT): A comprehensive compilation of locations and metadata for streamgages throughout Arizona
Martha Whitaker, UA
Throughout Arizona, streamgages are used for various purposes by different entities. However, a lack of collaboration among the entities means it is difficult to identify the locations and other information about these gages. This drastically reduces the efficiency and accuracy of gathering information for streamflow data. The Arizona Streamgage Catalog (AZStreamCAT) was initiated in February 2023 to develop an online, publicly available catalog that provides an overview of the quantity and location of non-USGS streamgages. By coalescing pre-existing data, the catalog can inform stakeholders, improve resource management, and help establish protocols for future data collection. Data for AZStreamCAT were collected by direct communication with operators and via online surveys. Respondents were asked to provide latitude, longitude, and elevation coordinates for each gage location. The resulting map includes layers showing county boundaries, watershed boundaries, and rivers. It will aggregate virtually every streamgage in Arizona and will ultimately be published on ArcGIS Online as a hosted feature layer for public use.
Preliminary watershed water budget analysis for forest restoration sites in Coconino National Forest, northern Arizona
Cole Denver, NAU
Climate change and European settlement have altered the natural structures of large portions of the Coconino National Forest in northern Arizona. The increased occurrence of high-severity wildfires due to these changes has led to the establishment of various restoration programs to protect the region’s forests and their watersheds. Several studies have looked at the impact of forest restoration on watershed hydrology; however, information on how these project affect the large-scale hydrology of the forests is still minimal. To better assess these effects, a study was initiated to compare the impacts of differing levels of restoration in six subwatersheds within the Upper Lake Mary watershed. Its goal is to accurately describe pretreatment hydrologic conditions to provide a baseline for assessing the efficacy of future restoration projects. This study synthesizes legacy precipitation, discharge, groundwater recharge, soil moisture, and runoff data — combined with novel evapotranspiration (ET) data — to create a holistic water balance for each subwatershed, uncover pretreatment hydrologic trends that correlate with climate, and devise a reliable method for calculating ET. The results will provide crucial information for policy and decision-making as the region plans for future water availability.
Spatially distributed base-flow index analysis of Arizona streams
Caelum Mroczek, NAU
Base flow is important for identifying the groundwater contribution to streams, especially in arid environments. One metric, the base-flow index (BFI) — the ratio of groundwater-derived flow to total flow — provides a normalized measure of groundwater dependence. Historically, variable BFI values can indicate watersheds that may be enhanced by future managed aquifer recharge. This study examines BFI throughout Arizona, based on data from instrumented streams in federal, state, and city managed lands, at a range of elevations. It involved using runoff data to estimate the natural recharge volume, runoff values, and base-flow contribution and then using BFI and geophysical watershed properties with a random forest regression analysis to estimate the base-flow of ungauged rivers. Since many natural channels in Arizona are intermittent or ephemeral, we focused our BFI characterization on non-perennial streams.
Arizona’s abandoned mines: Remediation efforts to improve watershed health
Adam Stratman, ADEQ
Arizona has numerous abandoned mines, with estimates ranging from 1,300 to 200,000. These mines threaten human health and the environment by causing safety risks, degrading streams, and decreasing biodiversity. Through collaborative partnerships, ADEQ’s Watershed Improvement Unit has been remediating abandoned mines since 2018. This poster highlights some of the remediated mines and details the process used to identify and prioritize sites for future remediation.
Investigating the seasonal variability of metals concentrations and their transport mechanisms in intermittent streams
Justin Headley, UA
In the 1960s, anomalously high metal concentrations in southeastern Arizona streams led to the discovery of large porphyry deposits of copper and molybdenum in upstream drainage areas of the Santa Rita Mountains. No large-scale mining operation has yet to occur in the Santa Ritas; however, tailings at one proposed mine site would have the potential to negatively impact downstream water quality in Lower Cienega Creek and Davidson Canyon — one of Arizona’s “outstanding waters.” Water infiltrating through tailings can decrease pH through sulfide oxidation, the hydrolysis of iron (III) minerals, and other mechanisms. Additionally, the chemical weathering of ore brought to the surface can mobilize toxic metals that were previously sequestered underground. Assessing any future mine-related contamination requires characterizing the baseline levels and seasonal variability of metals in the surface waters of Davidson Canyon and Lower Cienega Creek. We hypothesize that these metals concentrations follow a seasonal cycle, with see higher concentrations in groundwater-fed baseflow during the dry seasons (spring and fall) and lower concentrations during winter and summer, when recent precipitation makes up a larger component of surface flow. To test this hypothesis, we collected samples in Davidson Canyon and Lower Cienega Creek under both base flow and high flow conditions; we also analyzed major ion and isotope chemistry.
Using GIS mobile applications to streamline field data collection and data management
Tristan Dicke, Montgomery & Associates
Collecting surface water data in the field is a time-consuming process, with large amounts of metadata that can take a tedious amount of time to digitize. The use of map- and form-based mobile applications — ESRI’s Survey123, ArcGIS Field Maps, and VuSitu — can streamline and automate data collection and reduce the amount of time required to manually entering data. These applications integrate QA/QC and help reduce paper-to-digital data entry errors. Field data can be compiled and uploaded to a viewable data management system within hours of collection. These applications also can give users the tools they need to visualize the data distribution and can minimize the risk of injury to field personnel in remote locations.