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Filter Total Items: 2,153
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Year Published: 2017

Understanding the past to interpret the future: Comparison of simulated groundwater recharge in the upper Colorado River basin (USA) using observed and general-circulation-model historical climate data

In evaluating potential impacts of climate change on water resources, water managers seek to understand how future conditions may differ from the recent past. Studies of climate impacts on groundwater recharge often compare simulated recharge from future and historical time periods on an average monthly or overall average annual basis, or compare...

Tillman, Fred D.; Gangopadhyay, Subhrendu; Pruitt, Tom

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Year Published: 2017

Bed texture mapping in large rivers using recreational-grade sidescan sonar

The size-distribution and spatial organization of bed sediment, or bed ‘texture’, is a fundamental attribute of natural channels and is one important component of the physical habitat of aquatic ecosystems. ‘Recreational-grade’ sidescan sonar systems now offer the possibility of imaging, and subsequently quantifying bed texture at high resolution...

Hamill, Daniel; Wheaton, Joseph M.; Buscombe, Daniel D.; Grams, Paul E.; Melis, Theodore S.
Hamill, D., Wheaton, J.M., Buscombe, D., and Melis, T.S., 2016, Bed texture mapping in large rivers using recreational-grade sidescan sonar, in Constantinescu, G., Garcia, M., and Hanes, D., eds., River Flow 2016--Eighth International Conference on Fluvial Hydraulics, St. Louis, Mo., July 12-15, 2016: Boca Raton, Fla., Taylor and Francis Group, CRC Press, doi: 10.1201/9781315644479-51, p. 306-312, http://www.crcnetbase.com/doi/10.1201/9781315644479-51.

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Year Published: 2017

Effects of varying obliquity on Martian sublimation thermokarst landforms

Scalloped depressions in the Martian mid-latitudes are likely formed by sublimation of ice-rich ground. The stability of subsurface ice changes with the planetary obliquity, generally becoming less stable at lower axial tilt. As a result, the relative rates of sublimation and creep change over time. A landscape evolution model shows that these...

Dundas, Colin M.

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Year Published: 2017

Cryptic invasion of Northern Leopard Frogs (Rana pipiens) across phylogeographic boundaries and a dilemma for conservation of a declining amphibian

Anthropogenic introduction of species is a major contributor to loss of biodiversity. Translocations within the range of a species are less frequently recognized, but have the potential for negative effects as well. Genetic mixing may lead to loss of local adaptations or further decline through outbreeding depression. These cryptic invasions may...

O'Donnell, Ryan P.; Drost, Charles A.; Mock, Karen E.
O’Donnell, R.P., Drost, C.A., and Mock, K.E., 2017, Cryptic Invasion of Northern Leopard Frogs (Rana pipiens) across Phylogeographic Boundaries and a Dilemma for Conservation of a Declining Amphibian: Biological Invasions, v. (online), http://link.springer.com/article/10.1007/s10530-016-1320-1 and http://dx.doi.org/10.1007/s10530-016-1320-1.

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Year Published: 2017

Groundwater response to the 2014 pulse flow in the Colorado River Delta

During the March-May 2014 Colorado River Delta pulse flow, approximately 102 × 106 m3 (82,000 acre-feet) of water was released into the channel at Morelos Dam, with additional releases further downstream. The majority of pulse flow water infiltrated and recharged the regional aquifer. Using groundwater-level and microgravity data we...

Kennedy, Jeffrey; Rodriguez-Burgueno, Eliana; Ramirez-Hernandez, Jorge
Kennedy, J., et al., Groundwater response to the 2014 pulse flow in the Colorado River Delta. Ecol. Eng. (2016), http://dx.doi.org/10.1016/j.ecoleng.2016.10.072

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Year Published: 2017

A history of the 2014 Minute 319 environmental pulse flow asdocumented by field measurements and satellite imagery

As provided in Minute 319 of the U.S.-Mexico Water Treaty of 1944, a pulse flow of approximately 132 million cubic meters (mcm) was released to the riparian corridor of the Colorado River Delta over an eight-week period that began March 23, 2014 and ended May 18, 2014. Peak flows were released in the early part of the pulse to simulate a spring...

Nelson, Steven M.; Ramirez-Hernandez, Jorge; Rodriguez-Burgeueno, J. Eliana; Milliken, Jeff; Kennedy, Jeffrey R.; Zamora-Arroyo, Francisco; Schlatter, Karen; Santiago-Serrano, Edith; Carrera-Villa, Edgar
: Nelson, S.M., et al., A history of the 2014 Minute 319 environmental pulse flow as documented by field measurements and satellite imagery. Ecol. Eng. (2016), http://dx.doi.org/10.1016/j.ecoleng.2016.10.040

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Year Published: 2017

Analysis of local slopes at the InSight landing site on Mars

To evaluate the topography of the surface within the InSight candidate landing ellipses, we generated Digital Terrain Models (DTMs) at lander scales and those appropriate for entry, descent, and landing simulations, along with orthoimages of both images in each stereopair, and adirectional slope images. These products were used to assess the...

Fergason, Robin L.; Kirk, Randolph L.; Cushing, Glen E.; Galuszka, Donna M.; Golombek, Matthew P.; Hare, Trent M.; Howington-Kraus, Elpitha; Kipp, Devin M; Redding, Bonnie L.

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Year Published: 2017

Incorporating temporal heterogeneity in environmental conditions into a somatic growth model

Evaluating environmental effects on fish growth can be challenging because environmental conditions may vary at relatively fine temporal scales compared to sampling occasions. Here we develop a Bayesian state-space growth model to evaluate effects of monthly environmental data on growth of fish that are observed less frequently (e.g., from mark-...

Dzul, Maria C.; Yackulic, Charles B.; Korman, Josh; Yard, Michael D.; Muehlbauer, Jeffrey D.
Dzul, M.C., Yackulic, C.B., Korman, J., Yard, M.D., and Muehlbauer, J.D., 2016 Incorporating temporal heterogeneity in environmental conditions into a somatic growth model: Canadian Journal of Fisheries and Aquatic Sciences, 10.1139/cjfas-2016-0056

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Year Published: 2017

Geomorphic change and sediment transport during a small artificial flood in a transformed post-dam delta: The Colorado River delta, United States and Mexico

The Colorado River delta is a dramatically transformed landscape. Major changes to river hydrology and morpho-dynamics began following completion of Hoover Dam in 1936. Today, the Colorado River has an intermittent and/or ephemeral channel in much of its former delta. Initial incision of the river channel in the upstream ∼50 km of the delta...

Mueller, Erich R.; Schmidt, John C.; Topping, David J.; Shafroth, Patrick B.; Rodríguez-Burgueño, Jesús Eliana ; Ramírez-Hernández, Jorge; Grams, Paul E.
Mueller, E.R., Schmidt, J.C., Topping, D.J., Shafroth, P.B., Rodríguez-Burgueñod, J.E., Ramírez-Hernández, J., and Grams, P.E., 2016, Geomorphic change and sediment transport during a small artificial flood in a transformed post-dam delta: The Colorado River delta, United States and Mexico: Ecology Engineering, online version, http://dx.doi.org/10.1016/j.ecoleng.2016.08.009

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Year Published: 2017

Low-cost grass restoration using erosion barriers in a degraded African rangeland

Rangeland degradation, typified by extensive bare ground and soil erosion, is a serious problem around the world. In sub-Saharan Africa, rangeland degradation threatens the food security of millions of people who depend on livestock and the region's large mammalian wildlife diversity. We tested the ability of five simple, low-cost erosion barriers...

Kimiti, David W; Riginos, Corinna; Belnap, Jayne
Kimiti, D. W., Riginos, C., and Belnap, J., 2017, Low-cost grass restoration using erosion barriers in a degraded African rangeland: Restor Ecolology, v. 25, p. 376-384. http://dx.doi.org/10.1111/rec.12426.

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Year Published: 2017

Prestoration: Using species in restoration that will persist now and into the future

Climate change presents new challenges for selecting species for restoration. If migration fails to keep pace with climate change, as models predict, the most suitable sources for restoration may not occur locally at all. To address this issue we propose a strategy of “prestoration”: utilizing species in restoration for which a site...

Butterfield, B.J.; Copeland, Stella M.; Munson, Seth M.; Roybal, C.M.; Wood, Troy E.
Butterfield, B.J., Copeland, S.M., Munson, S.M., Roybal, C.M., and Wood, T.E., 2016, Prestoration: using species in restoration that will persist now and into the future: Restoration Ecology, v. (online), http://onlinelibrary.wiley.com/doi/10.1111/rec.12381/abstract and http://dx.doi.org/10.1111/rec.12381.

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Year Published: 2017

Interannual to multidecadal climate forcings on groundwater resources of the U.S. West Coast

Study regionThe U.S. West Coast, including the Pacific Northwest and California Coastal Basins aquifer systems.Study focusGroundwater response to interannual to multidecadal climate variability has important implications for security within the water–energy–food nexus. Here we use Singular Spectrum Analysis to quantify the teleconnections between...

Velasco, Elzie M.; Gurdak, Jason J.; Dickinson, Jesse E.; Ferré, T.P.A.; Corona, Claudia

Nine USGS Science Centers are administered by the Pacific Regional office, which is headquartered in Sacramento, California.