Anne J. Jefferson

The increasing frequency and intensity of hydrometeorological events such as floods driven by climate change necessitates reliable, spatially explicit decision support tools like Flood Inundation Maps (FIMs). Developing effective FIMs is challenging, as varying data complexities need to be managed whilst effectively communicating forecasts and uncertainties to diverse audiences. Visualisation literature offers some empirical evidence for designing effective user‐controlled decision support tools such as FIMs. Still, research and operational gaps persist, particularly with respect to whether FIMs are appropriately designed, communicated, translated, and interpreted to support effective near‐term flood response decisions. Our study draws from research in visualisation and user‐centred design literature to conduct a structured diagnostic assessment of eight (inter)national FIM forecast visualisations using independent task‐based usability questionnaires and guided workshops. We identified challenges such as unclear key messages, inconsistent colour schemes, ambiguous symbols, unclear legends, and inefficient interface layouts, likely reducing the usability and decision support value of these eight FIMs. We recommend identifying product key messages; designing user interfaces around those key messages; ensuring that visual features such as colours aid heuristic decision‐making and cognitive processing; and incorporating dynamic, user‐controlled features to enhance usability and decision‐making for technical and non‐technical audiences. Finally, we provide evidence‐informed design considerations that will improve the accessibility, interpretability, and effectiveness of FIMs as decision support tools, ultimately improving the process and outcomes of flood response decisions.

Suspended sediment is a critical water quality parameter and an indicator of geomorphic processes, but suspended sediment dynamics in urban streams may not conform to the first-flush model widely used for other pollutants. We analyzed discharge and turbidity data for 367 events from three urban watersheds (impervious cover 16–45%) in Cleveland, Ohio (USA). Less intensely urbanized watersheds exhibit higher turbidity compared to that of the most highly urbanized watershed. Proportionally, more counterclockwise hysteresis is observed in the two less urbanized watersheds, and more clockwise hysteresis occurs in the highly urbanized watershed. However, hysteresis patterns are driven by different mechanisms in each watershed, and geomorphic analysis was critical to identifying the underlying mechanisms. In the least urbanized watershed, spatial rainfall variability controls sediment hysteresis. In the intermediate watershed, the erosion of upstream weathered shale banks during dry periods plays a significant role in the sediment supply and shaping hysteresis. In the most urbanized watershed, high eroding banks in downstream reaches lead to more frequent clockwise hysteresis. Overall, we suggest that as the impervious surfaces increase, the availability of instream sediments (bed and banks) plays an increased role in suspended sediment dynamics, and geomorphology remains essential for guiding management decisions.

The CUAHSI Virtual University is an interinstitutional graduate training framework that was developed to increase access to specialized hydrology courses for graduate students from participating US institutions. The program was designed to capitalize on the benefits of collaborative teaching, allowing students to differentiate their learning and access subject matter experts at multiple institutions, while enrolled in a single course at their home institution, through a framework of reciprocity. Although the CUAHSI Virtual University was developed prior to the COVID-19 pandemic, the resilience of its online education model to such disruptions to classroom teaching increases the urgency of understanding how effective such an approach is at achieving its goals and what challenges multi-institutional graduate training faces for sustainability and expansion within the water sciences or in other disciplines. To gain faculty perspectives on the program, we surveyed (1) water science graduate program faculty who had served as instructors in the program, (2) water science graduate program faculty who were aware of the program, but had not participated, and (3) departmental chairs of participating instructors. Our data show widespread agreement across respondent types that the program is positive for students, diversifying their educational opportunities and increasing access to subject matter experts. Concerns and factors limiting faculty involvement revolved around faculty workload and administrative barriers, including low enrollment at individual institutions. If these barriers can be surmounted, the CUAHSI Virtual University has the potential for wider participation within hydrology and adoption in other STEM disciplines.

The paper examines relationships between stormwater control measure (SCM) priorities and environmental value orientations among stormwater managers in Cleveland, Ohio and Denver, Colorado, metro regions with contrasting environmental conditions and policy contexts. While studies show that governance explains differences in broad SCM priorities, less is known about what motivates individual “street level bureaucrats” who influence decisions at the project level. Drawing from cognitive social science perspectives, this study surveyed stormwater professionals (n = 185) about primary and co‐benefit SCM priorities and environmental value orientation. Results revealed different primary SCM priorities by region: Cleveland and Denver respondents prioritized quantity and quality goals, respectively, reflecting regional context. Co‐benefit priorities correlated to two environmental value orientation clusters — “Traditional Technocrats” with relatively anthropocentric orientations and “Champions” with relatively ecocentric orientations — who were equally abundant in both regions. Findings suggest that environmental value orientation influences co‐benefit priorities, which may have implications for project level articulation of policy.

Faculty Perspectives on a Collaborative, Multi-Institutional Online Hydrology Graduate Student Training Program

In semi‐arid cities, urbanization can lead to elevated baseflow during summer months. One potential source for additional water is lawn irrigation. We sought to quantify lawn irrigation contributions to summertime baseflow in Denver, Colorado, USA using water‐stable isotope (δ¹⁸O and δ²H) analysis of surface water, tap water, and precipitation. If lawn irrigation contributed significantly to baseflow, we predicted the isotopic composition of Denver's urban streams would more closely resemble local tap water than precipitation or streamflow from nearby grassland watersheds. We expected tap water to be distinctive due to local water providers importing source water from high elevations. Thirteen urban streams and two grassland streams were selected for sampling. None of the streams had high‐elevation headwaters or wastewater effluent, and the grassland streams did not receive irrigation. Tap water was sampled from five water service areas. The grassland streams flowed for 60% of summer 2019 while urban streams flowed for 90%–100% of the summer. An isotope mixing analysis using tap and precipitation end‐members over a two week antecedent period estimated that tap water contributed 65% ± 10%–93% ± 3% with a mean of 80% of urban baseflow on specific days in late summer. After taking contributions from infrastructure leakage into account, we estimated that lawn irrigation return flows made up 32% ± 10%–82% ± 21% of analyzed baseflow. Quantifying lawn irrigation contributions to urban baseflow provides a basis for understanding how changes to lawn irrigation efficiency would affect water yield in the Denver metropolitan area.