Reagan Waskom

The Creation and Maintenance of Wetland Ecosystems from Irrigation Canal and Reservoir Seepage in a Semi-Arid Landscape

Irrigation has increased agricultural productivity in the arid American West, and has greatly altered the natural landscape. This study sought to identify the hydrologic processes linking irrigation canals and reservoirs to wetlands. We mapped wetlands within an irrigation company service area in northern Colorado, measured groundwater levels, and used stable oxygen isotopes to identify groundwater sources. We related vegetation composition in study wetlands to environmental variables to identify the types of wetlands supported by leakage from irrigation conveyance and storage structures. Ninety-two percent of wetlands were visually connected to the irrigation infrastructure. Wetland water tables varied with adjacent canal flow, and isotopic data indicated that wetlands within the study area were recharged solely by canal leakage. Wetland vegetation composition was related to both soil salinity and groundwater depth. Salt flats formed in areas with high salinity, marsh communities in areas with low salinity and higher standing water, and meadow communities in areas with low salinity and water tables near the ground surface. Though land conversion and water diversions have led to dramatic reductions in historic wetland area in some places, it is clear from our study that current agricultural landscapes create wetlands that rely on irrigation water.

Water acquisition and use during unconventional oil and gas development and the existing data challenges: Weld and Garfield counties, CO

Colorado has recently experienced a significant increase in unconventional oil and gas development, with the greatest concentration of activity occurring in Weld and Garfield counties. Water for oil and gas development has received much attention mainly because water resources are limited in these regions and development is taking place closer to populated areas than it did in the past. Publicly available datasets for the period 2011-2014 were used to identify water acquisition strategies and sources of water used for oil and gas. In addition, the annual average water used in these two counties was quantified and compared to their total water withdrawals. The analysis also quantified the water needed for different well types, along with the flowback water that is retrieved. Weld and Garfield counties are dissimilar in respect to development practices for water acquisition, preferred well type and the fate of flowback water. But at the same time, this difference displays how geological characteristics, water availability, and administration localities are the key elements along with economics in the decision making process within the oil and gas sector. This effort also revealed data challenges regarding accessibility and reliability of reported information, and the need for additional data. Improving the understanding of the unconventional oil and gas sectors water use will help identify possible effects and tradeoffs on the local/regional level, which could diminish the conflicting perspectives that shape the water-energy discussions. This would complement the ability to make informed water resources planning and management decisions that are environmentally and socially acceptable.

Correlating Denitrification Rates to Soil Texture using Hierarchical Cluster Analysis

Widespread pollution of ground and surface waters from nitrate (NO3-) contamination is of global concern to both public health and the environment. Quantifying the attenuation potential of nitrate in the sub-surface is thus very important. Denitrification rates have been found to vary significantly both spatially and temporally depending on different soil characteristics. Current knowledge of sub-surface denitrification is site specific; thus limiting its use for making NO3- removal predictions on a watershed scale. In the present work, attention has been focused on assessing the influence of soil textural classes on denitrification. Data were compiled and analyzed from the literature of relevant work, and the variability in denitrification rates was assessed. A multivariate statistical approach was used to determine if denitrification rates could be correlated to soil textural classes. In addition, cumulative frequency diagrams (CFD) proved useful for quantifying the variations in denitrification rates. The hierarchical cluster analysis (HCA) provided valuable information regarding the similarities between the different soil experiments by grouping them together into three distinct groups of experiments that were closely related to the grain size distribution. Although the HCA did not provide any information how the three different soil groups are related to denitrification rates, the CFD showed that the denitrification rates vary significantly with soil group. Clayey soils were found to have the highest denitrification rates, while sandy and silty soils have the lowest. This work will allow for more realistic assessments of denitrification on a watershed scale.

Water-Food-Energy: Nexus and Non-Nexus Approaches for Optimal Cropping Pattern

Given the water-food-energy interconnections, integrated planning, policy and management using the nexus approach are required for the food production system. In this study the nexus and non-nexus approaches are compared to propose an optimal cropping patternthat considers water, energy and economic parameters. Linear optimization was applied to compare i) the nexus approach utilizing an objective function to maximize a water-food-energy nexus index and 2) the non-nexus approach utilizing three objective functions for water use, energy use, and agricultural net return. The study showed that the nexus approach is the best. Applying it through a water-food-energy nexus index provides a holistic method for identifying an optimal cropping pattern that reduces water and energy consumption and increases the agricultural net return.

Irrigation canals are newly created streams of semi-arid agricultural regions

The natural hydrologic processes that create and maintain the diversity of aquatic and riparian habitats along the Worlds streams and rivers have been profoundly altered by humans. Diversion of surface water to support production agriculture in arid and semi-arid regions has degraded ecosystems but also created potential habitat along and in canals specifically designed to transport water. The prevalence of canals and the immense amount of water used for agriculture have created these new artificial stream systems. This study demonstrates the potential for irrigation canals to support riparian and aquatic communities similar to natural streams in urban/residential and agricultural landscapes. We examined the hydrological and ecological characteristics of streams and irrigation canals in urban and agricultural landscapes in northeastern Colorado, typical of regions dominated by irrigation-supported agriculture. Flow patterns in canals depended on their size and had a range of patterns with potential ecological consequences such as rapidly rising and falling water stage, intermittent dry periods, and delayed peak and base flows compared to natural streams. Despite these hydrologic differences, the taxonomic and functional composition of riparian plant and aquatic macroinvertebrate communities indicated that ecological similarities exist between streams and canals, but are dependent, in part, on their landscape setting with stronger similarities in agricultural areas. We also tested the influence of characterizing taxa by functional groups using physiology, ecology and life history traits to explore attributes of habitats including woody canopy structure and water quality. We used a Habitat Quality Index (HQI) that combined physical and biological measures into a single index. Streams scored higher on average within agriculture and urban/residential settings compared to canals; however, one third of urban canals scored above the average of agricultural streams. This multidisciplinary study shows that irrigation canals can be valuable riparian and aquatic habitat, especially in regions with severely degraded streams.

Accessing Flexibility: A Historical Institutional Analysis of Water Use for Oil and Gas Development in Colorado

ABSTRACT US Mountain West Water access and allocation institutions have a history of adapting policy and practice to increase flexibility for diverse water uses. We examine how flexible access has developed over time and space by operationalizing the historical institutional (HI) theoretical and methodological framework. We trace historical water access for oil and gas (OG) development in Colorado, working from contemporary water right data to examine historical critical events, policies, and political contexts. OG water use has iteratively shaped water governance institutions in the top OG producing regions of Colorado, Weld, and Garfield Counties. The analysis suggests that to more accurately capture institutional change and continuity in resource allocation systems, an analysis of informal institutions is an essential theoretical contribution to the HI framework. While increased flexibility makes multiple uses easier, policies favor the most economically lucrative beneficial uses and generate issues of transparency, an important consideration for the public’s resource. Future practices of flexibility are contingent on market structures and institutional access mechanisms shaped during previous government policy processes, illuminating the value of the HI framework to inform future water policy.

Comment on “Developing and Implementing an Effective Public Outreach Program”

We commend and thank J. A. Harrison et al. for the feature article “Developing and implementing an effective public outreach program” (see Eos, 90(38), 333–334, 22 September 2009), which brought attention to a critical component of knowledge development, namely, effective outreach. We strongly support their recommendations. Here we offer additional suggestions and sources of programming resources that may assist young scientists interested in involving stakeholders in research and extension-outreach programs. Since 2001 the U.S. Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA), in partnership with land grant universities, has developed and implemented a national network of regionally integrated water quality research and outreach programs through the National Integrated Water Quality Program (NIWQP). Engaging young, research-oriented faculty into these outreach programs has been a challenge and a priority of NIFA programs. Through its regional network, the NIWQP has developed standing teams of extension-outreach professionals and researchers who can provide logistical support and leveraging funds for young faculty to identify and connect with stakeholders. Standing teams assist young investigators in planning/assessment methods to ensure that outreach activities address stakeholder needs and progress toward a set of defined outcomes or impacts.