The process of river avulsion builds floodplains and fills alluvial basins. We report on a new style of river avulsion identified in the Landsat satellite record. We found 69 examples of retrogradational avulsions on rivers of densely forested fluvial fans in the Andean and New Guinean alluvial basins. Retrogradational avulsions are initiated by a channel blockage, e.g., a logjam, that fills the channel with sediment and forces water overbank (dechannelization), which creates a chevron-shaped flooding pattern. Dechannelization waves travel upstream at a median rate of 387 m/yr and last on average for 13 yr; many rivers show multiple dechannelizing events on the same reach. Dechannelization ends and the avulsion is complete when the river finds a new flow path. We simulate upstreammigrating dechannelization with a one-dimensional morphodynamic model for open channel flow. Observations are consistent with model results and show that channel blockages can cause dechannelization on steep (10–2 to 10–3), low-discharge (~101 m3 s–1) rivers. This illustrates a new style of floodplain sedimentation that is unaccounted for in ecologic and stratigraphic models.

We investigated interfacial processes affecting metal mobility by wood ash under laboratory-controlled conditions using aqueous chemistry, microscopy, and spectroscopy. The Valles Caldera National Preserve in New Mexico experiences catastrophic wildfires of devastating effects. Wood samples of Ponderosa Pine, Colorado Blue Spruce, and Quaking Aspen collected from this site were exposed to temperatures of 60, 350, and 550 °C. The 350 °C Pine ash had the highest content of Cu (4997 ± 262 mg kg), Cr (543 ± 124 mg kg), and labile dissolved organic carbon (DOC, 11.3 ± 0.28 mg L). Sorption experiments were conducted by reacting 350 °C Pine, Spruce, and Aspen ashes separately with 10 μM Cu(II) and Cr(VI) solutions. Up to a 94% decrease in Cu(II) concentration was observed in solution while Cr(VI) concentration showed a limited decrease (up to 13%) after 180 min of reaction. X-ray photoelectron spectroscopy (XPS) analyses detected increased association of Cu(II) on the near surface region of the reacted 350 °C Pine ash from the sorption experiments compared to the unreacted ash. The results suggest that dissolution and sorption processes should be considered to better understand the potential effects of metals transported by wood ash on water quality that have important implications for postfire recovery and response strategies.

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Supplemental InformationConcentrations of chemical constituents in water are given in milligrams per liter (mg/L).

For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment-visit https://www.usgs.gov or call 1-888-ASK-USGS.For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov.Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.Suggested citation: Blake, J.M., Miltenberger, Keely, Stewart, Anne, Ritchie, Andre, Montoya, Jennifer, Durr, Corey, McHugh, Amy, and Charles, Emmanuel, 2018, Assessment of water resources and the potential effects from oil and gas development in the Bureau of Land Management Tri-County planning area, Sierra, Doña Ana, and Otero Counties, New Mexico: U.S. Geological Survey Scientific Investigations Report 2017-5151, 87 p., https://doi.org/10.3133/sir20175151. ISSN 2328-0328 (online) iii AcknowledgmentsThis study was conducted in cooperation with the Bureau of Land Management. We would like to thank the following Bureau of Land Management employees for their assistance with this report: Dave Herrell and James Glover and the following U.S. Geological Survey employees for their assistance with this report: Jessica Hopple, Zach Shephard, Aurelia Mitchell, and Delbert Humberson. DatumVertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).Horizontal coordinate information is referenced to the North American Albers Datum of 1983 (NADAlbers 83).Horizontal coordinate information for cross sections is referenced to the North American Datum of 1983 (NAD 83).Altitude, as used in this report, refers to distance above the vertical datum. Supplemental InformationConcentrations of chemical constituents in water are given in milligrams per liter (mg/L). Abbreviations AbstractThe U.S.

No abstract