Transboundary aquuifers and binantional ground water database for the city of El Paso / Ciudad Juarez area

This document integrates official ground-water data from the United States and Mexico into one data base. These data were exchanged during a series of official meetings held in the offices of the Comisión Internacional de Limites y Aguas and the International Boundary and Water Commission, respectively in Ciudad Juárez, Chihuahua and El Paso, Texas. In addition to the international ground-water data base, this document includes a general report that summarizes and integrates the data graphically, and prepares other hydrogeologic maps and figures from the published literature. The graphics and maps in the report are mostly limited to the data in the attendant ground-water data base. However, additional surface water and ground-water data that were derived from previously published sources are presented in a few figures. The earlier data have been officially approved and archived by the U.S. Geological Survey, the International Boundary and Water Commission, and the Comisión Nacional del Agua. By international agreement the format of this general report provides limited processing of ground-water data, but no discussion of the significance or ramifications of the data or figures. The reader is at liberty to derive independent conclusions from these data that do not reflect the official opinions, either expressed or implied, of the principal participants in the study

Improving the efficiency and accuracy of evaluating aridland riparian habitat restoration using unmanned aerial vehicles

Unmanned Aerial Vehicles (UAVs) offer new opportunities for accurate, repeatable vegetation assessments, which are needed to adaptively manage restored habitat. We used UAVs, ground surveys, and satellite imagery to evaluate vegetation metrics for three riparian restoration sites along the Colorado River in Mexico and we compared the data accuracy and efficiency (cost and time requirements) between the three methods. We used an off-the-shelf UAV coupled with a multispectral sensor to determine Normalized Difference Vegetation Index (NDVI) and vegetation cover. We were unable to accurately classify vegetation by individual species, but by grouping riparian species of interest (cottonwood-willow, mesquite, shrubs), we achieved high overall model accuracies of 87–96% across sites (Kappa = 0.82–0.95). Producer’s and user’s accuracies were moderate to high for target vegetation classes (69–100%). UAV and ground-survey vegetation percent cover differed due to differences in methodologies (UAVs measure aerial cover; ground surveys measure foliar cover) and sources of error for each method. Correlations between UAV and ground survey vegetation cover were moderate (rs(90) = 0.24–0.58, p < 0.05). UAV NDVI (0.50–0.61) was significantly higher than Landsat NDVI (0.40–0.45) for all sites (p < 0.0001), likely due to presence of shadows with high NDVI values in UAV imagery. UAV NDVI, Landsat NDVI and UAV total vegetation cover were strongly correlated (rs(90) = 0.72–0.85, p < 0.05). UAV surveys were more labor- and cost- intensive than ground surveys in the first year, but were slightly less so in the second year. We conclude that UAVs can provide efficient, accurate assessments of riparian vegetation, which can be used in restoration site management. Due to UAV limitations to assess vegetation in a multi-layered canopy and inability to classify individual riparian species with similar spectral signals, we recommend a combined approach of UAV and ground surveys.Our Enterprise Rent-A-Car FoundationOpen access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Tracking cultural ecosystem services: water chasing the Colorado River restoration pulse flow

The release of environmental flows for ecological restoration is a challenge for water policymakers and managers as it involves complex trade-offs between productive and ecosystem uses of water. While it is crucial to demonstrate that such environmental flows produce the desired hydro-ecological results, allocation of environmental water is also influenced by perceived social values of this water. This research draws on the sub-field of socio-hydrology to track two-way feedbacks between humans and environmental flows and shows why and how social responses to river restoration can be monitored. Media coverage, posted comments and in-person interviews were used to track the responses of stakeholders who ‘chased’ the progress of the 2014 “pulse flow” down the Colorado River. These data framed in the cultural ecosystem systems typology revealed the temporal patterns and dynamics of dramatic shifts in socio-hydrologic processes and highlight the value of understanding the human wellbeing benefits and complex social values that are affected by freshwater restoration. This experimental and mixed evidence approach is useful for contexts where multiple stakeholders shape water resource management and we suggest it can be used by water decision-makers in their efforts to understand and appropriately respond to the social-ecological dynamics of a changing river system