From Domination of the Environment to Stewardship: A Historical Look at Denver Water's Public Communication 1933–2018

When most people think about the water coming from their kitchen faucets, they seldom consider where the water originates and how transporting it to their homes has environmental impacts. Utilities that supply water know the complexity of their systems, but from their position as a “utility,” they view their job as supplying safe water to their customers, not necessarily stewarding the environment. Consequently, when building large projects like dams, canals, and tunnels, utilities regard environmental disruption as a necessary byproduct of serving growing cities with water. Representations of these projects often replicate the “man conquering nature” frame, praising these engineering marvels for their defiance of nature. Denver Water, the utility that serves almost 1.5 million people on the arid eastern slope of the Colorado Rockies, has produced films describing its complex system since the early 20th century, and these films reveal an evolution of values from dominating nature to actively stewarding the environment. This paper reports on a grounded theory analysis of films produced by Denver Water between 1933 and 2018 examining how the films frame human relationships to the natural environment. The results reveal that the films increasingly express stewardship ideals over those of domination, with recent public communication actively advocating for environmental causes. The paper concludes by suggesting that we can learn important lessons from Denver Water about ethical organizational action for environmental stewardship.

Area Not Geographic Isolation Mediates Biodiversity Responses of Alpine Refugia to Climate Change

Climate refugia, where local populations of species can persist through periods of unfavorable regional climate, play a key role in the maintenance of regional biodiversity during times of environmental change. However, the ability of refugia to buffer biodiversity change may be mediated by the landscape context of refugial habitats. Here, we examined how plant communities restricted to refugial sky islands of alpine tundra in the Colorado Rockies are changing in response to rapid climate change in the region (increased temperature, declining snowpack, and earlier snow melt-out) and if these biodiversity changes are mediated by the area or geographic isolation of the sky island. We resampled plant communities in 153 plots at seven sky islands distributed across the Colorado Rockies at two time points separated by 12 years (2007/2008–2019/2020) and found changes in taxonomic, phylogenetic, and functional diversity over time. Specifically, we found an increase in species richness, a trend toward increased phylogenetic diversity, a shift toward leaf traits associated with the stress-tolerant end of leaf economics spectrum (e.g., lower specific leaf area, higher leaf dry matter content), and a decrease in the functional dispersion of specific leaf area. Importantly, these changes were partially mediated by refugial area but not by geographic isolation, suggesting that dispersal from nearby areas of tundra does not play a strong role in mediating these changes, while site characteristics associated with a larger area (e.g., environmental heterogeneity, larger community size) may be relatively more important. Taken together, these results suggest that considering the landscape context (area and geographic isolation) of refugia may be critical for prioritizing the conservation of specific refugial sites that provide the most conservation value.

A Rare Ice Storm in the Colorado Rockies

During the early morning hours of 9 January 2017, freezing rain developed across several valley locations in western Colorado. The resultant ice accumulation led to extremely treacherous travel conditions with hundreds of vehicle accidents reported in the vicinity of Grand Junction, Colorado and near Durango, Colorado. Additionally, widespread power outages were reported in Durango and near Steamboat Springs, Colorado. First responders were overwhelmed by the volume increase of emergency calls, and secondary services were requested from nearby municipalities to help with the increased workload. The emergency operations center in Mesa County, Colorado (Grand Junction) was activated as a result of the numerous accidents and injuries across the region. An ice storm of this magnitude has not been experienced in Grand Junction’s period of record, which dates back to 1893. A detailed investigation explores the physical processes responsible for this ice storm over the complex terrain of the Intermountain West.

Assessment of Radiative Forcing by Light-Absorbing Particles in Snow from In Situ Observations with Radiative Transfer Modeling

It is well established that episodic deposition of dust on mountain snow reduces snow albedo and impacts snow hydrology in the western United States, particularly in the Colorado Rockies, which are headwaters for the Colorado River. Until recently the snow observations needed to physically quantify radiative forcing (RF) by dust on snow were lacking, and analysis of impacts used a semiempirical relationship between snow optical properties and observed surface reflectance. Here, we present a physically based daily time series of RF by dust and black carbon (BC) in snow at Senator Beck Basin Study Area, Colorado. Over the 2013 ablation season (March–May), a snow–aerosol radiative transfer model was forced with near daily measured snow property inputs (density, effective grain size, and dust/BC concentrations) and validated with coincidentally measured spectral albedo. Over the measurement period, instantaneous RF by dust and BC in snow ranged from 0.25 to 525 W m−2, with daily averages ranging from 0 to 347 W m−2. Dust dominated particulate mass, accounting for more than 90% of RF. The semiempirical RF values, which constitute the continuous long-term record, compared well to the physically based RF values; over the full time series, daily reported semiempirical RF values were 8 W m−2 higher on average, with a root-mean-square difference of 16 W m−2.