Ashley Hullinger, UA

The Arizona Water Factsheet series was undertaken by the UA Water Resources Research Center (WRRC) as a new initiative to help address the local nature of water challenges and solutions in the state. While it is relatively easy to find information about supplies and demands in the state’s largest cities and Active Management Areas, finding water data at the county scale is much more difficult. Packaging concise information for a general audience, these snapshot resources are nested within the broader context of the state and address basic water supply and demand, regionally relevant challenges, and sustainability issues. The WRRC draws upon on a wide range of data for state, regional, and county-wide scales, which are narrowed based on the knowledge and expertise of local Technical Advisory Committees (TACs) including, but not limited to, Cooperative Extension staff. This process of pooling available data and then improving the product with local experts results in relevant and trustworthy factsheets for each county. The first factsheet for Maricopa County was released in December 2021; additional factsheets are well underway for Pima, Cochise, Graham, and Greenlee Counties. An important aspect of this work is acknowledging the distinct water resources situations, priorities, and values of each county, as defined by local stakeholders

Sarah Zurkee, NAU

The Four Forest Restoration Initiative (4FRI) is a project funded by the Forest Service that involves collaboration among multiple entities to restore 2.4 million acres of forest ecosystems in northern Arizona. Its primary goal is to improve the health and resiliency of the forest ecosystems. Few studies have analyzed the relationship between forest management and groundwater responses to forest management actions. In this 25-year study, the hydrologic response of  groundwater recharge and spring discharge, due to the watershed restoration treatments, was monitored at Hart Prairie Spring. Within Hart Prairie, water availability has been a concern for a rare high-elevation Bebb Willow community (Salix bebbiana), which depends on shallow groundwater. The approach to integrating both ecology and hydrogeology in the study was a favorable concept given the rare groundwater-dependent ecosystem (GDE) located in the Hart Prairie watershed. The analysis of the data involved both qualitative and quantitative methods. This included analyses of pre- and post-anthropogenic settlement and forest management treatments using annual hydrographs, seasonal precipitation data, and calculated annual runoff. Previous studies indicate that restoration efforts increased the number of flowing days for Hart Prairie Springs, possibly indicating an increase in groundwater recharge.

Hozhoo Emerson, ASU

English speakers have a plethora of Earth science teaching materials and resources for study. This is not necessarily true for other cultural communities, such as Indigenous nations, who are also disproportionately affected by Earth-science-related issues such as water quality and availability. The Navajo Nation, one of the largest Indigenous communities in the US, struggles with drought and lack of good water infrastructure. Our objective is to create tools that foster better education while preserving the Diné (Navajo) language, for teaching future generations to better protect water resources for their communities. In this place-based approach it is important to have people with cultural knowledge of their environment involved in decision-making. We are using ethnographic and literature-search research methods in ethnogeology and ethnohydrology to create cross-cultural, bilingual teaching materials and resources that will serve needs in Navajo country.

Zhaocheng Wang, ASU

Determining the streamflow regime of non-perennial rivers is important for regulatory purposes and resource management. Traditional methods for assessing the streamflow status in river reaches depend on field inspections and on-the-ground sensors that are usually labor-intensive and limited in coverage. To address these challenges, we developed a new approach using satellite data from a constellation of CubeSats (>200 in orbit), operated by Planet Labs. The method relies on the high spatial and temporal resolution (3 m, almost daily) of Planet imagery. Our algorithm detects robust differences in the surface reflectance of the near infrared band in areas within and outside of the river channel. We tested and calibrated the algorithm with streamflow gaging records in the Hassayampa River of central Arizona over three water years (2019-2021), finding good agreement in the annual number of flowing days (R² = 0.71, p < 0.0001). Subsequently, the number of flowing days was derived at 90 m intervals along the 186 km river, finding that 26% and 22% of the reaches in two ecoregions were classified as intermittent, with the remaining as ephemeral. Using a Hovmöller diagram, streamflow presence was visualized in unprecedented spatiotemporal detail, allowing estimates of daily flowing fractions and annual flowing days within reaches. In addition to determining the streamflow status, the new tool can provide insights into environmental transport and biogeochemical processes dependent on water presence in dryland rivers.

Katelyn LaPine, NAU

The influence of human activities of springs in the Coconino and Kaibab National Forests is an issue of growing concern and presents several problems not only for ecosystems, but for society as well. People rely on springs, not only for a direct water source, but for cultural significance, recreational use, ranching, and other non-market goods and services. Management action is essential to sustain the good and services of these complex ecosystems. We have developed nonmarket valuation outreach products to effectively communicate the value of non-market goods and services These outreach products will provide information to improve policy decisions. Nonmarket valuation is a methodology of economics used to estimate monetary values for goods and services that are not bought or sold in a traditional market. A GIS method was used to spatially analyze the estimated dollar amounts for attributes of spring ecosystems services. Spring Stewardship Institute’s (SSI) database of Spring ecosystem assessment protocol (SEAP) scores was incorporated for the creation and further analysis of spatial layers. SEAP scoring is a method of Spring ecosystem assessment, which uses 42 questions within six categories to rank the assessed spring condition. This protocol is used to define the criteria for each attribute layer and locate springs that will most likely respond to stewardship. Six map layers were created for each valued attribute and represent springs in the study area.

Abigail Kahler, UA

Water resources decisions are often made in the context of compromise among stakeholder groups with very different interests, and the extent of an aquifer is such that the impacts of present-day use may take decades to manifest, and equally long to mitigate. Initially small uncertainties can become magnified over time, proportionately increasing the environmental and monetary costs of a miscalculated decision. A stakeholder’s level of satisfaction with a compromise is defined by a utility function. A single outcome may have a low utility for one group and a high utility for another, according to the individual consequences. Hydrologic models help predict consequences but are limited by sparse data and uncertainty. This suggests a need for multiple models. It is worthwhile to pay special attention to less probable, still plausible models that predict consequential outcomes. These are called models of concern (MOCs). To achieve this, we propose a method of combining two ensembles. One is composed of the best-fitting calibrated models, and another entirely of MOCs. Combining these may represent stakeholder concerns more fully than a single ensemble, which only considers goodness-of-fit. This is an iterative process allowing the stakeholder to consider, and reconsider, their utility threshold according to the likelihood of negative outcomes. Preliminary results suggest the combined ensemble increases the identification of these outcomes.

Andrew Lewis, NAU

The Coconino and Kaibab National Forests have approximately 700 springs. 70% of the land within the forests is considered suitable for grazing. Many of the springs within the forests are ecologically degraded, mostly due to grazing. Springs and the ecosystems that they support are vital for plant biodiversity and wildlife habitat. Through a choice experiment we estimate a willingness to pay for attributes of springs. This project incorporates well-developed ecological research on springs to estimate non-market values. The outcome of this research is science- based knowledge used to inform policy decisions that will enhance environmental quality and improve the sustainability of land management practices. This research consists of three steps: focus groups, dissemination of a national survey, and analysis to determine the WTP. During the focus groups we determined the attributes of springs to be valued in the survey, municipal use, biological habitat, biodiversity, recreation use, cultural significance, ranching, flow, and cost. We plan to send an online survey to a national sample of potential respondents, with a target of 1,000 completed responses. Our results will provide relative values for attributes of springs included in the survey.

Zhaocheng Wang, ASU

Irrigation water use (IWU) associated with agricultural activities and urban green spaces provides substantial cooling effects and ameliorates heat. In central Arizona, IWU is responsible for nearly 80% of the water use and its future prediction is subject to large uncertainties due to land use and climate change. In this work, we simulated IWU using the Variable Infiltration Capacity (VIC) model at high spatiotemporal resolution (1-km, hourly) and improved the model through remotely-sensed vegetation and irrigation parameters. The model performance with respect to Land Surface Temperature was validated using ground observations and MODIS and GOES satellite products, finding overall good agreement. We then used a large set of scenario combinations (96 in total) to bracket plausible pathways of IWU change in the 21^st century under individualized and combined effects of land use and climate change. We found that land use change in the form of urban growth and intensification reduced IWU by -1 to -5% due to savings from cropland to urban conversion, while climate change effects led to increases in IWU by +3 to +8% due to the impact of warmer temperatures. When combined, total IWU changed from +2.5 to +4.4% in the intermediate future (2041-2071) and from -0.5 to 3.4% in the far future (2071-2100). These outcomes suggest that water savings from land use change will likely not be able to compensate for the increasing demand from urban irrigation when considering climate change, under current irrigation practices.

Morgan Ross, Environmental Defense Fund

The Colorado River water supply in Arizona is at risk due to climate change, overallocation, and water management policies.  This risk can be measured and interpreted through hydrologic models, however, this information is not easily accessible to water managers or decision makers.  This study produces an online platform that visually presents the existing hydrologic models and their associated inputs, outputs and assumptions, with the goal of enabling water managers and decision makers to understand the risk of climate change to the Colorado River water supply.

Dan Nunez, REGENESIS

There is a rapidly growing need to identify, vet, and deploy technically practicable and cost-effective remedies to treat per- and polyfluoroalkyl substances (PFAS) in groundwater and reduce the exposure risk to potential human and environmental receptors downgradient of PFAS-release sites. One remedial method that has gained interest from the groundwater remediation community is the in situ chemical sorption treatment of PFAS by colloidal activated carbon (CAC), with several Department of Defense-funded studies examining the treatment process now underway. There is also interest in the field performance observed over extended post-application timeframes for applications already in place.  To date, 17 in situ PFAS-contaminated groundwater remediation treatments using CAC have been installed. While most of these have occurred within the past one to two years, five sites have at least two years of performance data following CAC injection. This performance summary provides technical details on the design and application for PFAS treatment and summarizes the post-application groundwater results relative to baseline conditions at these five sites. These results will help inform groundwater remediation practitioners, project stakeholders, and regulators when considering remediation options for addressing PFAS in groundwater.

Eleonora Demaria, Pima County Regional Flood Control District

The Massingale retention basin in Pima County was built in the 80s to mitigate flooding issues from a 2.6-square-mile urban watershed. With a storage capacity of approximately 76 ac-ft, the basin’s flood attenuation is limited and flood spills over to Massingale Road during storm events equal to and greater than the 2-Year Return Period. Although Massingale Road is inverted, with an approximate capacity of 600 cfs, the 100-year storm event spill-over from Massingale Basin overwhelms the existing street capacity, flooding a downstream community. While  inspired by the success of the multi-purpose Kino Environmental Restoration Project (KERP) and considering the ongoing pressure in the region’s water resources, Pima County Regional Flood Control District (PCRFCD) examined the potential for a multipurpose benefit use of the basin that makes the surface runoff being stored in the basin available for turf irrigation for the nearby 5-acre Denny Dunn park. The result of this stormwater reuse concept could replace the current use of potable water to irrigate the park. The retrofit basin will result in flood mitigation for the downstream community. In this paper, the team evaluated the opportunities for multipurpose water reuse as well as flood mitigation opportunities at a reconnaissance level.

Nicholas Steverlynck, Hose Solutions

Most water wells are being designed and operated with the assumption that their performance stays fairly constant over years of operation. Drops in performance and rising maintenance costs are often overlooked, causing operational costs to skyrocket.
This poster focuses on pumping efficiencies and highlights how to save money while prolonging the life of our wells and pumping equipment — specifically, why costs increase over time, the long-term benefits of running a more efficient pumping operation, the benefits of FlexiRiser drop pipe over standard rigid drop/column pipe, and various installation and retrieval techniques.

Mark T. Murphy, NV5

With the recently (11/21) proposed draft rule defining Waters of the US (WOTUS) offered by the US Environmental Protection Agency and the US Army Corps of Engineers (the Agencies), the “new” test of Clean Water Act (CWA) applicability has returned to the “old,” science-based significant nexus analysis (SNA) that was used prior to 2015. No doubt, the Agencies will be offering guidance documents on how to complete SNAs; however, in 2015, the Agencies published an extensive review[1] (the Connectivity Report) on how streams under the jurisdiction of the CWA ecologically depend upon their watershed, including those streams that only flow during rain events (aka, ephemeral waters) and those that only flow because of treated effluent, agricultural return flows or other discharged water (effluent-dependent waters, EDWs). Given the exhaustive amount of research described in the Connectivity Report, and the many research projects over the last six years adding to the report’s conclusions, the Connectivity Report will almost certainly be the core of this future guidance.

Over the last two years, we have assisted clients in using the Connectivity Report to evaluate the health of two southern Arizona streams, an ephemeral stream (San Pedro River near Benson, Arizona) and an EDW (Santa Cruz River flowing through urban Tucson).  We used the flow pathway approach of the Connectivity Report to analyze the hydrological, hydrochemical, and hydrobiological, surface-water-mediated ecological connections, as individual and interactive transport mechanisms. We also examined “regional waters similarly situated,” as the SNA requires, focusing on ephemeral tributaries downstream of and within the studied reaches. Connections were defined by cause-and-effect couples that produced a potentially measurable individual or cumulative impact on the ecology of the studied reaches.

The exercise worked well, although both reaches have benefited from the subject of much peer-reviewed research and long USGS stream gage data collection. Applications in other watersheds may be limited where data is scarce. Nevertheless, the science and logic of ecological connectivity seems to clearly be the proper way to frame CWA applicability.

[1] Connectivity of Streams and Wetlands to Downstream Waters: A Review and Synthesis of the Scientific Evidence, https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=296